:root{--navy:#293e45;--coral:#df3d78;--cream:#FCFFE7;--blue:#a8e3df;--ink:#343957;--muted:#74788e;--line:#e8e9ed}*{box-sizing:border-box}body{margin:0;background:#f7f8fa;color:var(--ink);font-family:"Noto Sans Thai",Tahoma,system-ui,sans-serif;font-size:16px}button,input{font:inherit}button{cursor:pointer;transition:transform .15s,background .15s}button:active{transform:translateY(2px)}button:focus-visible,input:focus-visible,a:focus-visible{outline:3px solid #eb455f;outline-offset:4px}button:disabled{cursor:default;transform:none;opacity:.55}header{height:84px;background:white;display:flex;align-items:center;justify-content:space-between;padding:0 5%;border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:12px;font-size:22px;font-weight:850;color:var(--navy);letter-spacing:-.8px}.logo{display:grid;place-items:center;background:var(--coral);color:white;border-radius:13px;width:40px;height:40px;transform:rotate(-8deg);font-size:28px}.brand 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.progressbar i{background:linear-gradient(90deg,#21bdb7,#df3d78)}.navbutton.active{background:#e1f2ee;color:#215851}.primary{box-shadow:0 3px 0 #b33261}.node.open .nodebutton{border-color:#f4c5d6;box-shadow:0 5px 0 #af305d,0 0 0 7px #fff6}.brand small{letter-spacing:1px;font-size:9px;margin-top:2px}@media(max-width:600px){.brand{gap:9px}.brand img{width:62px!important;height:43px!important}.brand small{font-size:8px}}
/* Technology journey · additive upgrade, old progress IDs retained */
.eras{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-bottom:20px}.era{border:1px solid #dce7e4;border-radius:14px;padding:14px 16px;background:white}.era b,.era span{display:block}.era b{font-size:13px;color:#33534d}.era span{font-size:11px;color:#798782;margin-top:4px}.era.current{background:#e7f4ee;border-color:#99c6b9}.era.locked{background:#f1f2f4;color:#859091}.map{background:#f0e8d6;border-color:#e3d7bd}.choices{display:grid;grid-template-columns:1fr 1fr;gap:13px;max-width:510px;margin:0 auto}.choice{display:flex;align-items:center;gap:16px;text-align:center;background:white;border:2px solid #dce7e5;border-bottom-width:5px;border-radius:15px;padding:16px 18px;color:var(--navy);font-weight:750;min-height:72px;font-size:26px;overflow-wrap:anywhere}.choiceletter{display:grid;place-items:center;background:#eef2f2;font-size:13px;color:#6c817d;border-radius:8px;min-width:27px;height:27px}.choice.correct{background:#e6f5e8;border-color:#72ad83;opacity:1}.choice:disabled{opacity:.55}.techcard{background:white;border:1px solid #e0e5e4;border-radius:24px;overflow:hidden;margin-top:26px}.techhero{background:#eee5d2;display:flex;align-items:center;padding:28px;gap:25px}.techhero h2{font-size:25px;margin:8px 0}.wheelillustration{font-size:100px;color:#95734d;line-height:1.2}.techbody{padding:25px 32px;line-height:1.8;max-width:830px}.techbody h3{color:var(--navy);margin:22px 0 8px}.techbody p{margin:0 0 15px}.collectionbadge{font-size:12px;color:#77744f}.sources{padding-left:20px;font-size:13px}.sources a{color:#277e76;text-underline-offset:4px}.small{font-size:11px}.lockedtech{font-size:80px;color:#c8c8c2}.collectioneras{grid-template-columns:1fr 1fr;margin-top:25px}@media(max-width:600px){.eras{gap:7px}.era{padding:11px 9px;border-radius:11px}.era b{font-size:11px}.era span{font-size:9px}.choices{gap:10px}.choice{padding:13px 12px;font-size:25px;gap:10px;min-height:70px}.techhero{padding:20px;gap:13px}.techhero h2{font-size:20px}.wheelillustration{font-size:66px}.techbody{padding:20px}.navbutton{padding:7px 7px;font-size:9px}.heading h1{font-size:22px}.heading p{max-width:235px}.collectioneras{grid-template-columns:1fr}.collectionbadge{font-size:10px}}
.maptags{display:flex;align-items:center;flex-wrap:wrap;gap:9px;margin:-7px 0 19px}.maptag{display:inline-flex;padding:5px 12px;border:1px solid #b8d8cc;border-radius:30px;color:#337062;background:#ebf6ef;font-size:12px;font-weight:650}.maptags small{font-size:11px;color:#828b8c}@media(max-width:600px){.maptags{gap:7px;margin-top:-3px}.maptags small{font-size:9px}.maptag{font-size:11px;padding:4px 10px}}
.nodestatus{position:absolute;left:92px;top:-2px;display:grid;place-items:center;border-radius:50%;width:23px;height:23px;background:#e6f4e6;color:#456b45;border:2px solid white;font-size:12px}.nodestatus.locked{background:#e4e8df;font-size:10px}.node:not(.open):not(.done) .nodebutton{background:#e8ecdf;color:#8a9681}.lesson-dialog{border:1px solid #dce6e1;border-radius:23px;padding:32px;width:min(490px,calc(100% - 32px));color:var(--ink);box-shadow:0 24px 70px #1e303a33}.lesson-dialog::backdrop{background:#22393b77;backdrop-filter:blur(3px)}.dialog-close{position:absolute;right:15px;top:13px;font-size:18px}.detail-number{display:inline-grid;place-items:center;background:#e5f2ec;border-radius:17px;color:#34695c;width:57px;height:57px;font-size:26px;font-weight:800}.detail-status{font-size:12px;color:#69817a;margin-left:14px}.lesson-dialog h2{margin:24px 0 12px;font-size:24px}.lesson-dialog p{font-size:14px;color:#70807b}.lesson-dialog .actions{margin-top:24px}.lesson-dialog .detail-start{white-space:normal}@media(max-width:600px){.nodestatus{left:74px}.lesson-dialog{padding:26px 23px}.lesson-dialog h2{font-size:21px}.lesson-dialog .actions{flex-direction:column}.lesson-dialog button{min-height:44px}}
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/* Responsive, code-native technology infographic. Text stays selectable and accessible. */
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.stone-process figcaption span,.stone-uses figcaption span{font-size:12px;overflow-wrap:break-word}@media(max-width:600px){.stone-process figcaption b,.stone-uses figcaption b{font-size:13px}.stone-process figcaption span,.stone-uses figcaption span{font-size:12px}}
.mystery-collection{text-align:center;padding:35px 22px}.mystery-card{display:grid;place-items:center;width:105px;height:140px;margin:0 auto 22px;background:linear-gradient(140deg,#e4f0e6,#f6e3ec);border:3px solid white;outline:1px solid #dce3da;border-radius:16px;color:#638878;font-size:60px;font-weight:700;transform:rotate(-6deg)}.owned-card-list{display:flex;flex-wrap:wrap;gap:13px;margin:25px 0}.owned-card{border:1px solid #dce4d9;background:#fffdf7;border-radius:15px;padding:13px 17px;color:#345548;min-width:140px;max-width:200px;text-align:center}.owned-card.selected{border:2px solid #6a9a82;background:#edf5eb}.owned-card>span{display:block;width:80px;margin:auto}.owned-card b,.owned-card small{display:block;font-size:13px}.owned-card small{font-size:10px;color:#859481;margin-top:5px}@media(max-width:600px){.owned-card-list{gap:9px}.owned-card{min-width:125px;padding:10px 12px;flex:1}.owned-card>span{width:67px}.mystery-collection p{font-size:13px}}
.learn-concept{font-size:16px;color:#597369;background:#eaf3ed;padding:18px 22px;border-radius:15px}.learn-example,.learn-guided{border:1px solid #dce7df;background:white;border-radius:20px;padding:25px;margin-top:21px}.learn-example h2,.learn-guided h2{line-height:1.8;font-size:26px;margin:10px 0 19px;overflow-wrap:anywhere}.learning-visual{padding:19px;border-radius:15px;background:#f3f6ef}.counting-dots{display:grid;grid-template-columns:repeat(10,minmax(0,1fr));gap:8px;max-width:430px;margin:auto}.count-dot{aspect-ratio:1;border-radius:50%;background:#70a994;display:grid;place-items:center;color:#986672;max-width:34px;font-weight:800}.count-dot.added{background:#df9bb1}.count-dot.removed{background:#e7e7de;border:2px dashed #bcafb0;font-size:23px}.dot-legend{font-size:12px;text-align:center;color:#687e72;margin-top:14px}.learn-steps{padding-left:24px;margin:22px 0 0;color:#536b60;font-size:15px;line-height:1.9}.learn-steps li{padding-left:5px;margin-bottom:9px}.learn-start{width:100%;margin-top:4px}.reopen-learn{display:block;margin:0 0 15px auto;color:#48776b;font-size:12px}.learn-guided .choices{max-width:none}.learn-guided #learnhint{display:block;margin:17px auto 0}@media(max-width:600px){.learn-example,.learn-guided{padding:20px 16px}.learn-example h2,.learn-guided h2{font-size:23px}.learn-concept{font-size:14px;padding:16px}.learning-visual{padding:15px 10px}.counting-dots{gap:5px}.count-dot.removed{font-size:17px}.learn-steps{font-size:14px}.dot-legend{font-size:11px}.learn-view .lessonhead{gap:10px}.learn-view .lessonhead .secondary{font-size:11px;padding:10px 13px}}
/* Map-wide optional Learn: chapter navigation, no per-node interstitials. */
.learn-chapters{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px;margin:24px 0}.learn-chapters button{text-align:left;white-space:normal;min-width:0;font-size:14px}.learn-chapters .chapter-active{background:#d9f5ee;border-color:#238a80;color:#174e49}.learn-actions{display:flex;gap:12px;flex-wrap:wrap;align-items:center;margin-top:24px}.learn-actions .learn-start{margin:0}.journey-modes{flex-wrap:wrap}@media(max-width:420px){.learn-chapters{grid-template-columns:1fr}.learn-actions>*{width:100%}}
/* Fuelup isometric atlas: world → real math region → numbered practice nodes. */
:root{--ink:#303d41}body{background:#faf9f3}main{min-width:0}.world-heading{display:flex;align-items:center;justify-content:space-between;gap:20px;margin-bottom:26px}.world-heading h1{font-size:36px;margin:8px 0}.world-counter{white-space:nowrap;font-size:12px;border:1px solid #dde6de;border-radius:50px;padding:10px 14px;background:#fffdf7;color:#668278}.world-map{position:relative;isolation:isolate;aspect-ratio:1000/650;overflow:hidden;border:1px solid #d9e9e2;border-radius:28px;background:#eaf6f1;box-shadow:0 15px 40px #557d6412;animation:atlas-out .42s ease-out}.world-map>svg{position:absolute;inset:0;width:100%;height:100%;pointer-events:none}.world-pin{position:absolute;transform:translate(-50%,-50%);background:none;border:0;color:#314541;display:flex;align-items:center;flex-direction:column;cursor:pointer;max-width:90%;z-index:2;padding:8px}.pin-mark{display:grid;place-items:center;width:51px;height:51px;border-radius:50%;background:#e75284;border:5px solid #fff4ef;color:white;font-size:17px;font-weight:800;box-shadow:0 6px 0 #aa365c,0 13px 24px #304f4140}.pin-label{margin-top:16px;padding:11px 20px;display:flex;flex-direction:column;background:#fffef7f5;border-radius:15px;border:1px solid #ffffff;box-shadow:0 7px 22px #2d5b4b1c;white-space:nowrap}.pin-label b{font-size:16px}.pin-label small{font-size:11px;color:#558b7c;margin-top:4px}.world-pin:hover .pin-mark{background:#ce3e70}.world-pin:focus-visible{outline:3px solid #e75284;border-radius:20px;outline-offset:5px}.world-compass{position:absolute;top:24px;right:27px;display:flex;flex-direction:column;text-align:center;font-size:10px;color:#6e9286;gap:0}.world-compass span{font-size:42px;line-height:1}.world-map-caption{position:absolute;bottom:20px;left:24px;color:#578274;font-size:11px;letter-spacing:1px}.region-list{margin:24px 0 14px}.region-card{display:flex;align-items:center;gap:19px;border:1px solid #e0e6dd;border-radius:21px;background:#fffdf8;padding:22px 24px}.region-card-number{display:grid;place-items:center;flex:0 0 52px;height:52px;border-radius:16px;background:#e3f1e9;color:#378071;font-size:22px;font-weight:800}.region-card h2{font-size:21px;margin:5px 0}.region-card p{font-size:12px;color:#74867b;margin:4px 0}.region-card .primary{margin-left:auto;white-space:nowrap}.map-breadcrumb{display:flex;align-items:center;flex-wrap:wrap;gap:12px;font-size:12px;color:#72857c;margin-bottom:23px}.map-breadcrumb button{font-size:12px;min-height:44px;padding:0}.isometric-region{min-height:0;height:660px;background:#eaf4eb;border:1px solid #d5e4d9;animation:atlas-in .42s ease-out;box-shadow:0 15px 35px #53744f10}.isometric-region .maplabel{top:20px;left:24px;background:#fffcf1d9;padding:8px 14px;border:1px solid #ffffff;border-radius:12px}.isometric-region .maplabel b{font-size:14px}.isometric-region .mapbottom{background:#fffaf0c9;padding:5px 12px;border-radius:20px;bottom:12px}.isometric-region .node{width:76px}.isometric-region .nodebutton{width:55px;height:55px;border-width:4px;font-size:21px;box-shadow:0 6px 0 #839e91,0 12px 12px #304f3920}.isometric-region .node.done .nodebutton{background:#378679;border-color:#cbefe0;box-shadow:0 6px 0 #205a53}.isometric-region .node.open .nodebutton{background:#e75284;border-color:#ffe1e7;box-shadow:0 6px 0 #ac3b60,0 0 0 7px #ffffff6b}.isometric-region .nodestatus{left:53px;top:-7px}.explorer-marker{left:-18px!important;top:-16px!important;width:25px;height:35px;background:#3b7273;border:2px solid #fff5e5;border-radius:9px 9px 7px 7px;filter:drop-shadow(2px 4px 1px #42664e30)}.explorer-marker:before{content:'';position:absolute;background:#e2b795;border:2px solid #fff5e5;width:17px;height:17px;left:1px;top:-14px;border-radius:50%}.explorer-marker:after{content:'';position:absolute;background:#dfba7a;left:-6px;top:-17px;width:29px;height:8px;border-radius:5px;box-shadow:0 -5px 0 -1px #bc9360}.explorer-marker i{position:absolute;right:-5px;top:6px;width:10px;height:19px;background:#d68d89;border:2px solid #fff5e5;border-radius:5px}@keyframes atlas-in{from{opacity:.35;transform:scale(.97)}to{opacity:1;transform:scale(1)}}@keyframes atlas-out{from{opacity:.4;transform:scale(1.02)}to{opacity:1;transform:scale(1)}}@media(max-width:650px){.world-heading{display:block;margin-bottom:20px}.world-heading h1{font-size:29px}.world-counter{display:inline-block;margin-top:8px}.world-map{aspect-ratio:auto;height:420px;border-radius:22px}.world-compass{top:17px;right:18px}.pin-label{padding:10px 14px}.pin-label b{font-size:14px}.region-card{padding:19px 16px;display:grid;grid-template-columns:44px minmax(0,1fr);gap:13px}.region-card-number{height:44px;font-size:18px}.region-card h2{font-size:18px}.region-card .primary{grid-column:1/-1;margin:3px 0 0;min-height:46px;width:100%}.isometric-region{height:660px}.isometric-region .maplabel{left:13px;top:14px}.isometric-region .nodebutton{width:48px;height:48px;font-size:18px}.isometric-region .nodestatus{left:49px;top:-8px}.explorer-marker{left:-9px!important;transform:scale(.85)}.world-map-caption{font-size:10px;left:16px}.map-breadcrumb{gap:8px}.map-breadcrumb button{font-size:11px}}@media(prefers-reduced-motion:reduce){.world-map,.isometric-region{animation:none}.world-pin,.nodebutton{transition:none}}
@media(max-width:650px){.world-pin .pin-label{position:absolute;top:60px;padding:7px 9px;white-space:normal;width:125px;max-width:none;text-align:center}.world-pin .pin-label b{font-size:11px;line-height:1.5}.world-pin .pin-label small{display:none}.world-pin{padding:0}.pin-mark{width:48px;height:48px}.world-map{height:380px}}
.base10-visual{background:#f3f7ed;border:1px solid #e1e7d9;border-radius:15px;padding:15px;display:grid;gap:13px}.base10-group{background:#fffdf7;border:1px solid #e2e8db;border-radius:10px;padding:12px;min-width:0}.base10-group>b{display:block;font-size:13px;color:#42796e}.base10-pieces{display:flex;align-items:flex-end;gap:5px;flex-wrap:wrap;min-height:24px;padding:12px 0}.ten-rod{display:inline-block;width:13px;height:70px;border:1px solid #398477;border-radius:3px;background:repeating-linear-gradient(to bottom,#69b9a6 0px,#69b9a6 6px,#d5ece3 6px,#d5ece3 7px)}.one-block{width:13px;height:13px;display:inline-block;background:#e8a0b4;border:1px solid #c77991;border-radius:2px}.base10-group small{font-size:12px;color:#728277}.base10-exchange{background:#fbedea;border:1px solid #ecd4d3;border-radius:12px;padding:13px}.base10-exchange>b{font-size:14px;color:#a65372}.base10-exchange p{font-size:13px;line-height:1.7;color:#806c70}
/* A connected continent; numbered touch targets have a full accessible list below. */
.world-map{aspect-ratio:1/1;max-height:950px}.region-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:13px}.region-card{display:grid;grid-template-columns:44px minmax(0,1fr);padding:19px;gap:13px;min-width:0}.region-card .primary{grid-column:1/-1;margin:2px 0 0;width:100%;font-size:12px}.region-card h2{font-size:18px;line-height:1.6}.region-card-number{height:44px;flex-basis:44px;font-size:18px}.pin-label{max-width:210px;text-align:center;white-space:normal}.pin-label b{font-size:13px;line-height:1.5}.world-map-caption{background:#fffff4b8;border-radius:20px;padding:7px 12px}.world-pin{max-width:32%}@media(max-width:650px){.world-map{height:700px;aspect-ratio:auto}.world-pin .pin-label{display:none}.world-pin{max-width:none}.world-compass{top:12px;right:12px}.region-list{grid-template-columns:1fr}.world-map-caption{font-size:9px;bottom:13px}.world-heading h1{font-size:29px}}@media(max-width:380px){.world-map{height:650px}}
.concept-visual{padding:18px;background:#eef5ec;border:1px solid #dae5d9;border-radius:15px;overflow:hidden}.concept-visual h3{font-size:16px;color:#397a6b;margin:0 0 14px}.place-columns{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:7px}.place-column{background:#fffdf7;text-align:center;border-radius:10px;padding:12px 4px;border-bottom:4px solid #badccc}.place-column b{display:block;font-size:26px;color:#386b62}.place-column span{display:block;font-size:11px;margin-top:5px;color:#687c73}.array-grid{display:grid;gap:5px;width:max-content;max-width:100%;margin:auto}.array-dot{width:17px;height:17px;border-radius:5px;background:#76b4a0;border:1px solid #508f80}.visual-equation{text-align:center;font-size:19px;font-weight:700;color:#3d6b60;margin:17px 0 3px;overflow-wrap:anywhere}.product-parts{display:flex;flex-wrap:wrap;gap:8px;margin-top:12px}.product-part{padding:10px;background:#fff9f3;border:1px solid #e0d8c7;border-radius:8px;flex:1;text-align:center;font-size:13px}.division-groups{display:flex;flex-wrap:wrap;justify-content:center;gap:9px}.division-cup{min-width:48px;padding:10px;border:2px solid #76a995;background:#fffdf8;border-radius:10px;display:flex;flex-wrap:wrap;gap:4px;justify-content:center;max-width:95px}.division-token{width:9px;height:9px;background:#e899b0;border-radius:50%}.division-rest{border:2px dashed #cf7992;border-radius:10px;padding:12px;text-align:center;margin-top:12px;font-size:13px;background:#fff1f4}.expression-tree{display:flex;justify-content:center;align-items:center;gap:6px;flex-wrap:wrap}.expression-branch{display:flex;flex-wrap:wrap;gap:5px;align-items:center;justify-content:center;padding:10px 8px;border:1px solid #c3d9cb;background:#fffdf5;border-radius:10px}.expression-branch .expression-branch{background:#e8f2e7}.expression-number{font-size:17px;font-weight:700}.expression-op{display:grid;place-items:center;border-radius:50%;background:#e7a9ba;color:#fff;width:24px;height:24px;font-weight:800}.expression-total{width:100%;text-align:center;font-size:12px;color:#457465;border-top:1px solid #d7e2d5;padding-top:6px}.concept-caption{font-size:12px;line-height:1.7;color:#698072;margin:14px 0 0;text-align:center}@media(max-width:420px){.concept-visual{padding:13px}.array-dot{width:13px;height:13px}.array-grid{gap:4px}.place-column b{font-size:23px}.expression-number{font-size:15px}.expression-branch{padding:7px 5px;gap:4px}}
.secondary-columns{margin-top:9px}.secondary-columns .place-column{background:#fbeced;border-bottom-color:#e2b3c0}
/* Screenshot-driven repair: map pins contain numbers only at EVERY breakpoint. */
.world-map .world-pin{width:56px;height:56px;padding:0;max-width:none;display:grid;place-items:center;min-height:56px}.world-map .pin-mark{width:48px;height:48px;font-size:1rem;line-height:1;border-width:4px;margin:0;flex:none}.world-map .world-pin:focus-visible{outline-offset:3px}.world-map .pin-label{display:none!important}.timeline-section{margin:30px 0 18px;min-width:0}.timeline-heading h2{font-size:23px;margin:0 0 8px}.timeline-heading p{line-height:1.8;margin:0 0 24px}.region-timeline{list-style:none;padding:0;margin:0;position:relative}.region-timeline:before{content:'';position:absolute;top:28px;bottom:28px;left:25px;width:2px;background:#cbded2}.timeline-stop{position:relative;padding:0 0 12px;margin:0;min-width:0}.timeline-detail{border:0;background:transparent;min-width:0}.timeline-detail>summary{position:relative;display:grid;grid-template-columns:52px minmax(0,1fr) 24px;gap:15px;align-items:center;list-style:none;cursor:pointer;min-height:72px;padding:10px 14px 10px 0;border-radius:14px;user-select:none}.timeline-detail>summary::-webkit-details-marker{display:none}.timeline-detail>summary::marker{content:''}.timeline-detail>summary:hover{background:#edf4ed}.timeline-detail>summary:focus-visible{outline:3px solid #d95a87;outline-offset:3px}.timeline-number{position:relative;z-index:1;display:grid;place-items:center;width:50px;height:50px;box-sizing:border-box;border:5px solid #faf9f3;border-radius:50%;background:#deeee5;color:#347c6e;font-size:16px;font-weight:800}.timeline-summary{min-width:0}.timeline-summary strong{display:block;color:#354b48;font-size:17px;line-height:1.65;white-space:normal;overflow-wrap:anywhere;font-weight:700}.timeline-progress{display:block;color:#829084;font-size:12px;line-height:1.7;margin-top:3px;white-space:normal;overflow-wrap:anywhere}.timeline-chevron{font-size:22px;color:#638a7b;text-align:center;line-height:1}.timeline-detail[open] .timeline-chevron{transform:rotate(180deg)}.timeline-detail[open] .timeline-number{background:#e77ca1;color:white}.timeline-content{margin:0 0 12px 67px;padding:8px 0 20px;border-bottom:1px solid #dfe7db;min-width:0}.timeline-subtitle{font-size:15px;color:#537a6b;line-height:1.8;margin:3px 0 15px}.timeline-content .maptags{margin:0 0 12px}.timeline-actions{display:flex;flex-wrap:wrap;gap:10px;margin-top:17px}.timeline-actions button{white-space:normal;overflow-wrap:anywhere;min-height:44px;max-width:100%;font-size:13px;line-height:1.6}.timeline-content p{overflow-wrap:anywhere}.world-heading{flex-wrap:wrap}.world-counter{white-space:normal}.layout,main{min-width:0}@media(max-width:650px){.timeline-detail>summary{grid-template-columns:46px minmax(0,1fr) 20px;gap:10px;padding-right:4px}.timeline-number{width:44px;height:44px;border-width:4px;font-size:14px}.region-timeline:before{left:22px}.timeline-content{margin-left:56px}.timeline-summary strong{font-size:16px}.timeline-progress{font-size:12px}.timeline-heading h2{font-size:21px}.timeline-actions{flex-direction:column}.timeline-actions button{width:100%}.side{padding-bottom:env(safe-area-inset-bottom,0px)}main{padding-bottom:calc(100px + env(safe-area-inset-bottom,0px))}}@media(prefers-reduced-motion:reduce){.timeline-chevron{transition:none}}
.world-map{min-height:520px}.world-map .world-pin:active{transform:translate(-50%,-50%)}
/* Eight readable stops per continent: preserve the approved pin/timeline density. */
.district-switcher{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;margin:0 0 21px}.district-button{display:flex;flex-direction:column;gap:4px;text-align:left;border:1px solid #d6e3da;border-radius:15px;background:#fffdf6;padding:16px;color:#61796c;min-width:0;white-space:normal;line-height:1.6}.district-button b{font-size:14px;overflow-wrap:anywhere}.district-button span{font-size:11px}.district-button.selected{background:#e1f1e9;border:2px solid #6aa18e;color:#315f52}.rational-visual{background:#edf5ed;border:1px solid #d9e5d6;border-radius:16px;padding:18px;min-width:0}.rational-visual h3{font-size:16px;color:#3d796b;margin:0 0 15px}.fraction-figure{margin:13px 0;padding:13px;background:#fffdf7;border-radius:12px;border:1px solid #e1e8da}.fraction-figure figcaption{display:flex;flex-wrap:wrap;justify-content:space-between;gap:8px;line-height:1.6;font-size:13px;color:#536e61;margin-bottom:9px}.fraction-strip{display:flex;width:100%;height:34px;border:2px solid #639583;border-radius:5px;overflow:hidden;background:#f7fbf2}.fraction-cell{flex:1;border-right:1px solid #83a990;background:#f7fbf2}.fraction-cell:last-child{border-right:0}.fraction-cell.filled,.fraction-fill{background:#76b6a2}.fraction-figure small{display:block;font-size:11px;color:#728675;line-height:1.7;margin-top:7px}.whole-badge{display:inline-block;background:#e7c5d0;border-radius:6px;padding:4px 9px;color:#795466;font-size:12px;margin:0 0 8px}.decimal-table,.proportion-table{width:100%;border-collapse:collapse;background:#fffdf7;font-size:13px;table-layout:fixed}.decimal-table th,.decimal-table td,.proportion-table th,.proportion-table td{border:1px solid #dbe4d7;padding:10px 5px;text-align:center;overflow-wrap:anywhere;line-height:1.6}.decimal-table th,.proportion-table th{background:#e2eee2;color:#527462;font-size:11px}.decimal-table td{font-size:20px;color:#497363}.decimal-table th:nth-child(3),.decimal-table td:nth-child(3){width:17px;padding:3px}.decimal-table th:first-child{width:24%}.proportion-table td{color:#407260;font-weight:700}.percent-grid{display:grid;grid-template-columns:repeat(10,minmax(0,1fr));gap:3px;width:min(100%,260px);margin:10px auto}.percent-cell{aspect-ratio:1;background:#fcfff4;border:1px solid #8eaf95;border-radius:2px}.percent-cell.filled{background:#dc94ad;border-color:#c17691}.rational-visual .visual-equation{font-size:17px;line-height:1.7}@media(max-width:500px){.district-switcher{gap:8px}.district-button{padding:12px 10px}.district-button b{font-size:12px}.rational-visual{padding:13px}.decimal-table td{font-size:17px}.decimal-table th{font-size:10px}.fraction-figure{padding:10px}.fraction-strip{height:30px}}
/* Shared adaptive answer entry. Large touch targets, no automatic keyboard focus. */
.answer-form{max-width:440px;margin:24px auto 4px;text-align:left}.answer-help{font-size:14px;color:#59666b;line-height:1.7;margin:0 0 12px}.answer-label{display:block;font-weight:700;margin-bottom:8px}.answer-form input{font-family:inherit;font-weight:700;font-size:26px;line-height:1.4;min-height:58px;border:2px solid #a9c2c7;border-radius:14px;padding:10px 16px;background:#fff;color:#263342;min-width:0;box-sizing:border-box;outline-offset:3px}.answer-form input:focus-visible{outline:3px solid #20ada8;border-color:#176c6c}.answer-form input[aria-invalid="true"]{border-color:#b73f54}.answer-form input:disabled{color:#263342;opacity:1;background:#edf7f4;border-color:#add3c8}.number-answer{display:block;width:100%;text-align:center}.answer-submit{width:100%;min-height:54px;margin-top:12px;font-size:17px}.answer-error{color:#a72e46;font-size:14px;font-weight:600;line-height:1.6;margin:8px 0;min-height:0}.answer-error:empty{display:none}.fraction-answer{display:grid;grid-template-columns:64px minmax(100px,1fr);gap:5px 12px;align-items:center;max-width:280px;margin:0 auto}.fraction-answer label{font-weight:700;font-size:14px}.fraction-answer input{width:100%;text-align:center}.fraction-answer-line{grid-column:2;border-top:3px solid #46565e;margin:2px 4px}.fraction-answer-form .answer-help{text-align:center}@media(max-width:480px){.answer-form{margin-top:18px}.answer-form input{font-size:24px}.answer-submit{min-height:56px}}
/* Always-visible route back to either continent, including during practice. */
.overview-bar{position:sticky;top:0;z-index:45;display:flex;gap:8px;align-items:center;padding:10px 12px;margin:0 -12px 18px;background:rgba(250,253,249,.98);border-bottom:1px solid #dce8e4;box-shadow:0 4px 12px #253b3b08}.overview-bar button{min-height:44px;padding:9px 14px;border:1px solid #c4d8d4;border-radius:12px;font-family:inherit;font-size:14px;font-weight:700;background:#fff;color:#31464a;cursor:pointer;white-space:nowrap}.overview-bar .overview-home{border:0;background:transparent;padding-left:0}.overview-bar .overview-range.selected{background:#e0f5ee;border-color:#26958c;color:#155c58}.overview-bar button:focus-visible{outline:3px solid #ee7897;outline-offset:2px}@media(max-width:480px){.overview-bar{gap:5px;padding:8px 6px;margin-left:-6px;margin-right:-6px}.overview-bar button{padding:8px 9px;font-size:12px}.overview-bar .overview-home{margin-right:auto}}
.overview-bar{flex-wrap:wrap}.overview-bar button{max-width:100%;white-space:normal;line-height:1.5;overflow-wrap:anywhere}@media(max-width:380px){.overview-bar .overview-home{flex-basis:100%;text-align:left;margin-right:0}.overview-bar .overview-range{flex:1 1 110px}}
/* Signed number and powers teaching models, with bounded token counts. */
.sign-controls{display:flex;justify-content:center;margin-top:9px;gap:8px}.sign-controls button{border:1px solid #aacdc3;border-radius:10px;background:#edf7f1;color:#345d56;padding:9px 14px;min-height:44px;font-size:14px}.signed-visual{background:#edf5f3;border:1px solid #cfdedb;border-radius:16px;padding:20px;min-width:0}.signed-visual h3{font-size:17px;color:#366c67;margin:0 0 16px}.signed-visual svg{display:block;width:100%;height:auto;min-height:140px;overflow:visible}.signed-legend{display:flex;flex-wrap:wrap;gap:9px 20px;padding:0;list-style:none;font-size:13px;line-height:1.7}.signed-legend li{background:#fffaf4;padding:7px 10px;border-radius:8px}.chip-columns{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px}.chip-group{margin:0;padding:11px;background:#fffcf6;border-radius:10px;min-width:0}.chip-group figcaption{font-size:12px;line-height:1.6;margin-bottom:9px}.chip-group figcaption b{display:block;font-size:20px}.signed-chips{display:flex;flex-wrap:wrap;gap:4px;font-size:12px}.signed-chip{display:inline-grid;place-items:center;width:22px;height:22px;border-radius:50%;font-size:17px;font-weight:800;border:1px solid}.signed-chip.positive{background:#cdf0e0;color:#216957;border-color:#7fb8a1}.signed-chip.negative{background:#f4cadb;color:#96385e;border-color:#cb8ca7}.zero-pair{display:flex;gap:8px;align-items:center;justify-content:center;font-size:13px;margin:18px 0 5px}.sign-table{width:100%;border-collapse:collapse;text-align:center;background:#fffcf5}.sign-table td,.sign-table th{padding:10px;border:1px solid #cdddce;line-height:1.6}.sign-table th{font-size:13px;color:#527b6b}.power-heading{text-align:center;font-size:30px;font-weight:800;color:#537270}.power-factors{display:flex;flex-wrap:wrap;align-items:center;justify-content:center;gap:8px;margin:18px 0}.power-factors b{padding:8px 12px;background:#fffbf2;border:1px solid #d4dfd0;border-radius:8px}.square-model{display:grid;aspect-ratio:1;width:min(240px,100%);margin:10px auto;background:#f3e6cb;border:3px solid #609e8c;place-content:stretch}.square-model i{border:1px solid #9abb9e;background:#d5eacb}.square-model strong{align-self:center;justify-self:center;font-size:26px}.square-label{text-align:center;font-size:14px;color:#446d60}@media(max-width:420px){.signed-visual{padding:13px}.chip-columns{gap:5px}.chip-group{padding:8px}.signed-chip{width:19px;height:19px;font-size:14px}.sign-table td{font-size:14px}}
.root-bounds{text-align:center;line-height:1.8;font-weight:700;color:#547a74;overflow-wrap:anywhere}.overview-bar .overview-range{flex:1 1 112px}.overview-bar .overview-home{flex:0 1 auto}@media(max-width:520px){.overview-bar .overview-home{flex-basis:100%;text-align:left;min-height:32px;padding-top:2px;padding-bottom:2px}.overview-bar .overview-range{flex:1 1 80px;padding:8px 6px;font-size:12px}}
.pair-answer{display:grid;grid-template-columns:60px minmax(0,1fr);gap:12px;align-items:center}.pair-answer label{font-weight:750}.pair-answer input{width:100%;text-align:center}.algebra-visual{background:#edf4f1;border:1px solid #d1e1d8;border-radius:16px;padding:18px;margin:16px 0;min-width:0}.algebra-visual h3{font-size:17px;color:#3b7066;margin:0 0 16px}.balance-beam{display:block;width:min(360px,100%);height:auto;margin:auto}.balance-states{list-style:none;padding:0;margin:12px 0}.balance-states li{margin:12px 0}.equation-sides{display:grid;grid-template-columns:minmax(0,1fr) 28px minmax(0,1fr);gap:6px;align-items:center;text-align:center}.equation-sides span{background:#fffaf0;border:1px solid #c7dacc;border-radius:10px;padding:12px 8px;font-size:18px;font-weight:700;overflow-wrap:anywhere}.equation-sides b{font-size:25px;color:#50796b}.balance-action{margin:8px 0;text-align:center;font-size:14px;color:#8e4871;line-height:1.7}.equation-check{padding:12px;background:#dceee4;border-radius:10px;font-size:14px;line-height:1.7}.algebra-groups{display:grid;gap:10px}.algebra-groups figure{margin:0;padding:12px;background:#fffaf1;border-radius:10px}.algebra-groups figcaption{font-size:13px;line-height:1.7;color:#64746d;margin-bottom:9px}.term-chips{display:flex;flex-wrap:wrap;gap:8px;align-items:center}.term-chip{padding:9px 14px;border-radius:8px;border:1px solid;font-weight:700;font-size:18px}.variable-term{background:#d0e9df;border-color:#83b9a9;color:#315f55}.constant-term{background:#f2d2df;border-color:#dca8bd;color:#814b67}.algebra-visual svg{display:block;width:100%;height:auto}.coordinate-plot{max-width:480px;margin:auto}.graph-scale{text-align:center;color:#597567;font-size:12px;line-height:1.7}.graph-legend{list-style:none;padding:0;display:flex;flex-wrap:wrap;gap:12px;font-size:13px;line-height:1.7}.graph-legend li{display:flex;align-items:center;gap:8px}.graph-legend i{display:inline-block;width:22px;height:4px;flex:none}@media(max-width:520px){.overview-bar{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:5px}.overview-bar .overview-home{grid-column:1/-1;min-height:30px}.overview-bar .overview-range{width:100%;min-width:0}.algebra-visual{padding:12px}.equation-sides span{font-size:16px;padding:10px 5px}.term-chip{font-size:16px;padding:8px 10px}}@media(max-height:500px){.overview-bar{position:static}}
.choice span:last-child{min-width:0;overflow-wrap:anywhere;white-space:normal}.choices.long-choices{grid-template-columns:1fr}.long-choices .choice{font-size:16px;line-height:1.8;text-align:left;padding:15px}.long-choices .choiceletter{flex-shrink:0}
.roots-answer{display:grid;grid-template-columns:88px minmax(0,1fr);gap:12px;align-items:center}.roots-answer label{font-size:14px;font-weight:700}.roots-answer input{width:100%;text-align:center;font-size:22px}.quadratic-visual{background:#f0f4e9;border:1px solid #d7e0cc;border-radius:16px;padding:18px;margin:16px 0;min-width:0}.quadratic-visual h3{color:#526f57;font-size:17px;margin:0 0 16px}.quadratic-visual figure{margin:10px 0;padding:12px;background:#fffdf6;border-radius:12px}.quadratic-visual figcaption{font-size:13px;color:#61735e;line-height:1.7;margin-bottom:10px}.polynomial-term-groups{display:flex;flex-wrap:wrap;gap:15px}.polynomial-term{min-width:0;max-width:100%}.polynomial-term>b{display:block;font-size:16px;margin-bottom:7px}.signed-algebra-tiles{display:flex;flex-wrap:wrap;gap:4px;max-width:240px}.algebra-tile{display:inline-flex;align-items:center;justify-content:center;border:1px solid;border-radius:4px;padding:4px;font-size:11px;min-width:23px;min-height:23px}.algebra-tile.power-1{min-width:45px}.algebra-tile.power-2{min-width:39px;min-height:39px}.algebra-tile.power-3{min-width:40px;min-height:39px;border-style:dashed}.plus-tile{background:#cee7cb;border-color:#91b68d;color:#315d42}.minus-tile{background:#f1cbd8;border-color:#d092a8;color:#853c5c}.area-factors{text-align:center;font-size:14px;line-height:1.7}.polynomial-area{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:4px;border:2px solid #769d78;padding:4px;width:min(380px,100%);margin:auto}.area-cell{padding:20px 10px;text-align:center;border:1px solid;font-size:18px;line-height:1.6;overflow-wrap:anywhere}.signed-area{border-style:dashed}.factor-product{display:flex;align-items:center;justify-content:center;gap:10px;flex-wrap:wrap;font-size:19px}.factor-product b{background:#d5e7ca;border:1px solid #a8c29a;padding:10px 14px;border-radius:9px}.factor-product strong{background:#f4ddc0;border:1px solid #d4bb96;padding:10px 14px;border-radius:9px}.quadratic-visual svg{display:block;width:100%;height:auto}.parabola-plot{max-width:480px;margin:auto}.parabola-features{font-size:14px;line-height:1.8;text-align:center;color:#3e7062;overflow-wrap:anywhere}@media(max-width:520px){.quadratic-visual{padding:12px}.area-cell{font-size:15px;padding:15px 8px}.roots-answer{grid-template-columns:75px minmax(0,1fr)}.roots-answer input{font-size:20px}.overview-bar .overview-range:last-child:nth-child(even){grid-column:1/-1}}
@media(max-width:520px){.overview-bar.exercise-overview{position:static}} /* Keep the larger five-continent navigator from covering mobile questions; bottom overview action remains reachable. */

.factor-product{align-items:flex-start;flex-direction:column}.factor-explanation{font-size:.92rem;color:var(--muted);font-weight:400}
.factor-product b,.factor-explanation{max-width:100%;overflow-wrap:anywhere;line-height:1.7}
/* Shared math presentation is separate from canonical answers and saved drafts. */
.math-inline{font-family:"Cambria Math","STIX Two Math",Georgia,"Times New Roman",serif;font-size:1.06em;font-weight:500;line-height:1.65;white-space:normal;word-break:normal;overflow-wrap:normal}.math-var{font-style:italic}.math-op{padding:0 .17em;white-space:nowrap}.math-sup{font-size:.68em;line-height:0;vertical-align:super;margin-left:.025em;font-weight:500}.math-frac{display:inline-flex;flex-direction:column;align-items:center;justify-content:center;vertical-align:middle;text-align:center;line-height:1.15;margin:.15em .15em;white-space:nowrap;font-size:.95em}.math-num{display:block;border-bottom:1.4px solid currentColor;padding:0 .17em .12em;min-width:.7em}.math-den{display:block;padding:.12em .17em 0;min-width:.7em}.math-frac .math-frac{font-size:.88em}.math-sqrt{display:inline-flex;align-items:stretch;vertical-align:middle;white-space:nowrap;margin:.08em .06em}.math-radical-sign{font-size:1.18em;line-height:1.2}.math-radicand{border-top:1.4px solid currentColor;padding:.05em .12em 0;line-height:1.35}.math-group{white-space:nowrap}.question .math-inline,.learn-worked h2 .math-inline,.learn-guided h2 .math-inline{line-height:1.95}.choice .math-inline{font-size:1.16em}.choice>span:last-child{min-width:0;max-width:100%;overflow-wrap:anywhere}.learn-steps li,.feedback,.hint p,.visual-equation{line-height:2;overflow-wrap:anywhere}.math-inline [aria-hidden="true"]{white-space:inherit}@media(max-width:520px){.question .math-inline{font-size:1em}.choice .math-inline{font-size:1.1em}.math-frac{margin:.15em .08em}.math-op{padding:0 .12em}}
.math-power,.math-product,.math-unary{white-space:nowrap}.math-sup .math-frac{font-size:1em}.math-number{font-variant-numeric:lining-nums tabular-nums}
.math-radicand{padding-top:.18em;padding-bottom:.02em} /* Clearance for superscripts below the radical overbar. */
.geometry-visual{margin:18px 0;padding:14px;background:#edf4ed;border:1px solid #d2e3d5;border-radius:18px;min-width:0}.geometry-visual svg{display:block;width:100%;max-width:490px;height:auto;margin:auto}.geometry-visual figcaption,.geometry-caption{font-size:13px;line-height:1.8;color:#617866;margin:10px 3px 0}.geometry-label,.geometry-angle-label{font:17px Tahoma,system-ui,sans-serif;fill:#334f49;paint-order:stroke;stroke:#fbfcf4;stroke-width:5px;stroke-linejoin:round}.geometry-angle-label{fill:#a14e73;font-size:16px}.geometry-figures{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}.geometry-figures .geometry-visual{padding:2px;margin:0}.geometry-comparison h3{font-size:16px;color:#4b7666}.geometry-visual .visual-equation{margin-bottom:0}@media(max-width:600px){.geometry-visual{padding:7px}.geometry-figures{grid-template-columns:1fr}.geometry-label{font-size:19px}.geometry-angle-label{font-size:18px}}
.geometry-axis-label{font:12px Tahoma,system-ui,sans-serif;fill:#768d80;paint-order:stroke;stroke:#fbfcf4;stroke-width:3px}.geometry-givens{color:#355f55!important;font-weight:650;text-align:center}
/* A named disclosure keeps every continent reachable without a growing button wall. */
.overview-bar{align-items:flex-start}.continent-switch{flex:1;min-width:0}.continent-switch summary{cursor:pointer;list-style:none;background:#fff;border:1px solid #c9e0da;border-radius:12px;min-height:46px;padding:12px 16px;font-weight:750;color:#385e57;display:flex;justify-content:space-between;gap:12px}.continent-switch summary::-webkit-details-marker{display:none}.continent-switch summary:focus-visible{outline:3px solid #df3d78;outline-offset:3px}.continent-switch[open] summary{background:#e5f3ee}.overview-ranges{display:flex;flex-wrap:wrap;gap:7px;padding:10px 0 0}.overview-ranges .overview-range{flex:1 1 125px}.overview-bar .overview-home{min-height:46px}@media(max-width:520px){.continent-switch{grid-column:1/-1;width:100%}.overview-ranges{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:6px}.overview-ranges .overview-range:last-child:nth-child(odd){grid-column:1/-1}.continent-switch summary{font-size:14px}}
.trig-side-legend{display:flex;flex-wrap:wrap;gap:8px;align-items:center}.trig-side-legend>b{flex-basis:100%;color:#455f58}.trig-side-legend>span{padding:7px 10px;border-radius:9px;background:#fff}.trig-role-opposite{border-left:5px solid #cb6490}.trig-role-adjacent{border-left:5px solid #39a69c}.trig-role-hypotenuse{border-left:5px solid #536e91}.calculation-aid{margin:16px 0;padding:14px 16px;border:1px solid #bbd8cf;background:#f2f8f1;border-radius:12px;line-height:1.9}.calculation-aid strong{display:block;color:#476a5d}.approximation-note{font-size:13px;color:#6d687b;line-height:1.8}
.calculation-aid summary{cursor:pointer;font-weight:750;min-height:44px;padding:8px 0;color:#426d60}.calculation-aid p{font-size:13px;line-height:1.8}.calculation-aid form{display:grid;gap:10px}.calculation-aid label{font-size:13px;font-weight:650}.calculation-aid select,.calculation-aid input{min-height:46px;max-width:100%;width:100%;padding:10px;border:1px solid #b7d2c7;border-radius:9px;background:white;color:#344f49;font:inherit}.calculation-aid output{display:block;padding:12px;background:#e4efe4;border-radius:9px;overflow-wrap:anywhere;font-size:14px}.calculation-aid select:focus-visible{outline:3px solid #df3d78;outline-offset:2px}
.math-function-name{font-style:normal}.math-function-argument{margin-inline-start:.12em}.math-function{display:inline}.math-degree-sign{font-style:normal}
.advanced-trig-visual{margin:14px 0;padding:0;max-width:100%;min-width:0}.advanced-trig-visual svg{display:block;width:100%;max-width:600px;height:auto;margin:auto}.advanced-axis-label{font:16px "Noto Sans Thai",sans-serif;fill:#345a54;paint-order:stroke;stroke:#fbfcf4;stroke-width:3px;stroke-linejoin:round}.advanced-trig-visual figcaption{font-size:.93rem;line-height:1.65;color:#4c665f;padding:4px 10px;overflow-wrap:anywhere}.advanced-formula-panel{padding:14px 18px;background:#eef7ef;border-left:4px solid #51aa9d;border-radius:12px;overflow-wrap:anywhere}.advanced-formula-panel p{line-height:1.9;margin:8px 0}

/* Indexed real cube roots retain a clear radicand and accessible spoken label. */
.math-cbrt{position:relative;margin-left:.23em}.math-root-index{font-size:.48em;position:absolute;left:-.37em;top:-.02em;line-height:1}

.isometric-region{min-height:var(--region-height,735px)}

.data-table-scroll{max-width:100%;overflow-x:auto;margin:12px 0;-webkit-overflow-scrolling:touch}.data-table-scroll table{width:100%;border-collapse:collapse;font-size:.95rem;background:#fff}.data-table-scroll th,.data-table-scroll td{padding:9px 12px;border:1px solid #d9e5df;text-align:center}.data-table-scroll th{background:#edf7f3}.data-table-scroll caption{text-align:left;margin-bottom:8px;color:#526462}.lower-data-visual,.lower-geometry-visual,.lower-number-visual{max-width:100%;overflow-wrap:anywhere}.lower-data-visual svg,.lower-geometry-visual svg,.lower-number-visual svg{display:block;max-width:100%;height:auto;margin:auto}
.data-chart-candidates{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px;margin:18px 0}.data-chart-candidates>article{min-width:0;padding:12px;border:1px solid #d9e5df;border-radius:16px;background:#fff}.data-chart-candidates h4{margin:0 0 8px}.data-chart-candidates summary{min-height:44px;padding:10px 0;cursor:pointer}.data-chart-candidates figure{margin:0}@media(max-width:650px){.data-chart-candidates{grid-template-columns:minmax(0,1fr)}}
/* Topic-first navigator: one quiet row; the catalogue exists only on demand. */
.overview-bar.topic-overview{display:flex;flex-wrap:nowrap;align-items:stretch;gap:8px;padding:8px 0;margin:0 0 18px;position:static;background:transparent;border:0;box-shadow:none}.topic-overview .overview-home{flex:0 0 auto;grid-column:auto;flex-basis:auto;min-height:52px;padding:8px 10px;font-size:13px;margin:0}.topic-overview .topic-trigger{display:flex;align-items:center;gap:12px;flex:1;min-width:0;text-align:left;padding:9px 15px;background:#edf7f2;border:1px solid #c7e3d9;border-radius:15px}.topic-label{flex:1;min-width:0}.topic-label small{display:block;font-size:10px;font-weight:500;color:#627c76;line-height:1.4}.topic-label strong{display:block;font-size:15px;line-height:1.45;overflow-wrap:anywhere}.topic-progress{font-variant-numeric:tabular-nums;font-size:13px;flex:none;text-align:right;color:#38685f}.topic-progress small{display:block;font-size:9px;font-weight:500}.topic-chevron{font-size:18px;color:#66877e}
.cp-dialog{width:min(880px,calc(100% - 32px));max-width:none;max-height:min(88dvh,850px);padding:0;border:1px solid #d1e3da;border-radius:25px;background:#fcfef8;color:#31464a;box-shadow:0 26px 100px #18352c40;overflow:auto;overscroll-behavior:contain}.cp-dialog::backdrop{background:#203c365e;backdrop-filter:blur(5px)}.cp-panel{padding:25px;min-width:0}.cp-header{display:flex;align-items:flex-start;justify-content:space-between;gap:16px;margin-bottom:18px}.cp-header h2{font-size:25px;margin:0 0 6px;line-height:1.35}.cp-header p{font-size:13px;color:#6c8079;margin:0;line-height:1.6}.cp-header button{border:1px solid #d1e2d9;border-radius:50%;background:white;width:44px;height:44px;flex:none;color:inherit;font-size:22px;cursor:pointer}.cp-controls{margin-bottom:20px}.cp-search{display:block;width:100%;border:1px solid #c5dcd2;border-radius:13px;background:white;font:inherit;font-size:16px;padding:13px 15px;box-sizing:border-box}.cp-controls label{display:block;font-size:13px;font-weight:700;margin-bottom:8px}.cp-filters{display:flex;flex-wrap:wrap;gap:7px;margin-top:12px}.cp-filter{border:1px solid #d3e2dc;border-radius:20px;background:#fff;padding:9px 15px;font:inherit;font-size:13px;min-height:42px;cursor:pointer;color:#526d64}.cp-filter[aria-pressed=true]{background:#285d54;color:#fff;border-color:#285d54}.cp-results{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}.cp-card{display:flex;gap:12px;align-items:flex-start;text-align:left;width:100%;min-width:0;padding:17px 13px;border:1px solid #d9e7de;border-radius:18px;background:white;color:inherit;cursor:pointer;font:inherit;transition:background .15s,border-color .15s}.cp-card:hover{background:#f1faf5;border-color:#79b6a4}.cp-card.cp-current{border-color:#58a78e;background:#edf8f1}.cp-thumb{width:94px;flex:0 0 94px;align-self:center}.cp-thumb svg{display:block;width:100%;height:auto}.cp-card-body{flex:1;min-width:0;overflow-wrap:anywhere}.cp-card-body h3,.cp-card-body strong{font-size:16px;line-height:1.5;margin:0 0 5px;display:block}.cp-card-body p{font-size:12px;line-height:1.65;margin:4px 0;color:#6d8278}.cp-card-body small{font-size:11px;line-height:1.7;color:#657f72;display:block}.cp-progress{font-size:11px;margin-top:10px;color:#397562}.cp-empty{grid-column:1/-1;text-align:center;background:#f0f6ef;padding:35px 20px;border-radius:15px;color:#597367;line-height:1.8}.cp-dialog :focus-visible{outline:3px solid #df6a98;outline-offset:3px}.cp-match{color:#9a4970!important}.cp-count{font-size:12px;color:#6b7e73;margin:0 0 12px}.cp-progress progress{display:block;width:100%;height:5px;margin-top:6px;accent-color:#5ea28a}
@media(max-width:600px){.topic-overview .overview-home{font-size:11px;padding:6px 4px;max-width:68px;line-height:1.4}.topic-overview .topic-trigger{gap:7px;padding:8px 10px}.topic-label strong{font-size:13px}.topic-label small{font-size:9px}.topic-progress{font-size:11px}.topic-chevron{font-size:15px}.cp-dialog{width:100%;max-height:92dvh;margin:auto 0 0;border-radius:24px 24px 0 0;border-bottom:0}.cp-panel{padding:22px 16px calc(20px + env(safe-area-inset-bottom))}.cp-results{grid-template-columns:minmax(0,1fr)}.cp-header h2{font-size:23px}.cp-thumb{width:86px;flex-basis:86px}.cp-card{padding:14px 12px}.cp-filter{padding:8px 13px}.cp-card-body h3,.cp-card-body strong{font-size:16px}}
@media(max-height:500px){.cp-dialog{max-height:96dvh}.cp-panel{padding-top:14px}.cp-header{margin-bottom:10px}.cp-header h2{font-size:20px}}@media(prefers-reduced-motion:reduce){.cp-card{transition:none}}
.cp-dialog .cp-header{height:auto;min-height:0;padding:0;border:0;box-shadow:none;background:transparent;position:static;max-width:none}.cp-dialog label.cp-search{padding:0;border:0;background:none;border-radius:0;font-size:13px}.cp-search input{display:block;width:100%;box-sizing:border-box;margin-top:8px;padding:13px 15px;border:1px solid #c5dcd2;border-radius:13px;background:#fff;color:#31464a;font:inherit;font-size:16px}.cp-thumb{display:block;height:auto}.cp-subtitle,.cp-range,.cp-progress{display:block}.cp-subtitle{font-size:12px;line-height:1.65;color:#6d8278;margin:3px 0}.cp-range{font-size:10px;line-height:1.7;color:#7a8e84;margin-top:5px}.cp-progress{font-size:11px;line-height:1.6}
.cp-match{display:block;font-size:11px;line-height:1.6;margin-top:6px}
@media(max-width:360px){.topic-overview .overview-home{width:40px;max-width:40px;flex-basis:40px;font-size:20px}.topic-overview .overview-home span{display:none}.cp-thumb{width:68px;flex-basis:68px}.cp-card{gap:9px}}@media(max-width:280px){.cp-card{flex-direction:column}.cp-thumb{width:58px;flex-basis:auto;align-self:flex-start}.cp-panel{padding-left:12px;padding-right:12px}.topic-progress{display:none}.cp-header h2{font-size:19px}}

.cp-range{color:#5c7167}.cp-subtitle,.cp-count{color:#536e61}.topic-label small{color:#506a61}
.cp-filter-help{font-size:11px;line-height:1.6;color:#536e61;margin:8px 0 0}
/* Contextual review stays beside the question, distinct from hints. */
.question-review{display:flex;align-items:center;gap:12px;flex-wrap:wrap;margin:14px 0 20px;text-align:left}.question-review button{min-height:46px;padding:10px 18px;border:2px solid #23968b;background:#effbf7;color:#225c56;font-weight:800;white-space:nowrap}.question-review small{flex:1 1 190px;line-height:1.5;color:#536e61}.question-review button:disabled{border-color:#ccd6d3;color:#61716b;background:#f3f6f4;cursor:default}.question-review button:focus-visible{outline:3px solid #db467d;outline-offset:3px}
.correct-transition{position:fixed;z-index:90;left:50%;top:42%;transform:translate(-50%,-50%);width:min(330px,85vw);padding:22px 18px;border-radius:24px;background:#e6faf4;color:#16594e;border:2px solid #2fb9a6;box-shadow:0 10px 45px #233b3930;text-align:center;pointer-events:none;animation:answer-pop .3s ease-out}.correct-transition strong{display:block;font-size:clamp(30px,7vw,46px);line-height:1.2}.correct-transition span{display:block;margin-top:8px;font-size:14px}.answer-recap{margin:20px 0;text-align:left}.answer-recap summary{cursor:pointer;padding:14px;background:#f0f7f4;border-radius:12px;font-weight:700}.answer-recap article{padding:12px 0;border-bottom:1px solid #dfe8e3}.answer-recap h3{font-size:17px;line-height:1.6}@keyframes answer-pop{from{transform:translate(-50%,-50%) scale(.96)}to{transform:translate(-50%,-50%) scale(1)}}@media(prefers-reduced-motion:reduce){.correct-transition{animation:none}}
/* Fuelup feedback: warm cream, turquoise and pink; shape + text, not color alone. */
.correct-transition{top:auto;bottom:calc(82px + env(safe-area-inset-bottom));width:max-content;max-width:90vw;padding:12px 20px;border-radius:19px;transform:translateX(-50%);background:#fffdf3;color:#303438;border-color:#37b7ac;box-shadow:0 8px 26px #28363722}.correct-transition.perfect{border-color:#db71a0}.correct-transition strong{display:flex;align-items:center;justify-content:center;gap:10px;font-size:30px}.correct-transition strong svg{width:24px;height:24px;fill:none;stroke:#dc6898;stroke-width:2;stroke-linejoin:round;stroke-linecap:round}.correct-transition.good strong svg{stroke:#28a89d;stroke-width:3}.correct-transition span{font-size:12px;margin-top:4px;color:#53665f}@keyframes answer-pop{from{transform:translateX(-50%) scale(.96)}to{transform:translateX(-50%) scale(1)}}

/* Topic landmarks and numbered exercises use deliberately different shapes.
   Name labels live in normal grid flow, never overlapping absolute overlays. */
.world-map.station-world{height:auto;min-height:0;max-height:none;aspect-ratio:auto;overflow:hidden;isolation:isolate}
.topic-station-grid{position:relative;z-index:2;min-height:650px;padding:35px 4% 42px;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));grid-auto-rows:minmax(110px,1fr);column-gap:8%;row-gap:12px;align-items:center}
.topic-station{position:relative;display:flex;flex-direction:column;align-items:center;justify-content:center;justify-self:center;align-self:center;min-width:44px;min-height:44px;max-width:100%;width:100%;padding:6px 2px;border:0;border-radius:15px;background:transparent;color:var(--navy,#303438);font:inherit;cursor:pointer;transition:background .16s ease}
.topic-station:hover{background:#ffffff65}.topic-station:focus-visible{outline:3px solid #d85c94;outline-offset:3px;background:#fffdf4dd}.topic-station:active{background:#e8f8f2c9;transform:none}
.station-landmark{display:block;position:relative;width:90px;height:60px;flex:none}.station-landmark>svg{display:block;width:100%;height:100%;filter:drop-shadow(0 4px 3px #31463d18)}
.station-progress{position:absolute;right:-8px;bottom:1px;padding:1px 5px;border-radius:5px;border:1px solid #b9d6cd;background:#fcfff5;color:#345a50;font-size:10px;line-height:1.5;font-weight:700;font-variant-numeric:tabular-nums}
.station-name{display:flex;flex-direction:column;align-items:center;max-width:100%;margin-top:2px;padding:3px 7px;border-radius:9px;background:#fffef2e8;color:#303c3b;font-size:14px;font-weight:750;line-height:1.55;text-align:center;box-shadow:0 2px 7px #3b5a4510;overflow-wrap:anywhere;white-space:normal}
.station-name>span{display:block;max-width:100%}.map-level-key{display:flex;flex-wrap:wrap;gap:6px 14px;align-items:center;font-size:12px;line-height:1.7;color:#526b61;margin:6px 0 13px}.map-level-key b{color:#32635b}.lesson-context{font-size:12px;line-height:1.65;color:#536e61;text-align:left;overflow-wrap:anywhere;margin:0 0 14px}.lesson-context span{padding:0 5px;color:#9c637f}
@media(max-width:600px){.topic-station-grid{padding:30px 3% 35px;column-gap:6%;min-height:650px;row-gap:10px}.station-landmark{width:78px;height:52px}.station-name{font-size:13px;padding:3px 5px}.station-progress{right:-5px}.map-level-key{font-size:11px}.world-compass{opacity:.65}}
@media(max-width:280px){.topic-station-grid{column-gap:8px;padding-inline:5px}.station-name{font-size:13px;padding-inline:2px}.station-landmark{width:66px;height:44px}}
@media(prefers-reduced-motion:reduce){.topic-station{transition:none}}

.decimal-revision-notice{display:flex;align-items:center;gap:14px;padding:15px 17px;margin:0 0 20px;border:1px solid #9dcfc3;border-radius:16px;background:#edf9f3;color:#34584e}.decimal-revision-notice>div{flex:1;min-width:0}.decimal-revision-notice strong{font-size:14px;line-height:1.7}.decimal-revision-notice p{font-size:12px;line-height:1.7;margin:5px 0 0}.decimal-revision-notice button{min-height:44px;flex:none}@media(max-width:520px){.decimal-revision-notice{align-items:flex-start;flex-direction:column}.decimal-revision-notice button{align-self:flex-end}}

/* Power entry teaches notation: two labeled fields or one exponent in its position. */
.sr-only{position:absolute!important;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
.power-pair-answer{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px;width:100%;max-width:440px;margin:18px auto;text-align:left}.power-pair-answer label{font-size:14px;font-weight:750;color:#345b54;line-height:1.7}.power-pair-answer input{display:block;width:100%;min-width:0;min-height:54px;margin-top:6px;padding:12px;border:2px solid #b7d8ce;border-radius:12px;background:white;color:#303438;font:inherit;font-size:22px;text-align:center;box-sizing:border-box}.power-pair-answer input::placeholder{font-size:12px;color:#60786e}
.exponent-entry{display:flex;align-items:flex-end;justify-content:center;gap:5px;width:fit-content;max-width:100%;margin:16px auto 20px;padding:5px 18px 9px;border-radius:18px;background:#eff8f2}.exponent-base{font-family:Georgia,'Cambria Math',serif;font-size:48px;line-height:1.4;padding-top:28px}.exponent-entry .exponent-answer{align-self:flex-start;width:94px;min-width:64px;max-width:38vw;min-height:48px;margin:0;padding:8px;border:2px solid #3aa99b;border-radius:10px;background:#fffdf6;color:#303438;font:inherit;font-size:22px;text-align:center;box-sizing:border-box}
.power-pair-answer input:focus-visible,.exponent-answer:focus-visible{outline:3px solid #da6b9c;outline-offset:3px}.power-preview-row{display:flex;align-items:center;justify-content:center;gap:13px;flex-wrap:wrap;margin:15px 0 20px;color:#61776e;font-size:12px}.power-answer-preview{display:block;min-width:90px;padding:8px 15px;border:1px dashed #b3cec3;border-radius:12px;background:#fffdf3;color:#344f49;font-family:Georgia,'Cambria Math',serif;font-size:30px;line-height:1.8}.power-answer-preview sup{font-size:.65em;vertical-align:super;margin-left:2px;line-height:0}.power-pair-answer input:disabled,.exponent-answer:disabled{opacity:.8;background:#eef4ed}
@media(max-width:400px){.power-pair-answer{gap:10px}.power-pair-answer input{font-size:20px;padding:10px 5px}.exponent-base{font-size:42px}.exponent-entry .exponent-answer{width:80px;font-size:20px}.power-preview-row{gap:8px}}
/* Supportive local skill review: no punitive restart or forced navigation. */
.review-support{padding:16px 18px;margin:14px 0 20px;border:1px solid #9ed8ce;border-left:5px solid #2fb9a6;border-radius:15px;background:#effaf6;color:#2f514a;text-align:left;line-height:1.65}.review-support p{font-size:14px;margin:7px 0 0}.review-progress{background:#fff5e9;border-radius:12px;padding:12px 16px;margin:14px 0;color:#624d3e;font-size:14px;line-height:1.6}.review-progress small{font-size:12px}.skill-review-list summary{cursor:pointer;padding:14px 0;font-weight:700}.skill-review-list ul{list-style:none;padding:0;margin:0}.skill-review-list li{display:flex;gap:12px;justify-content:space-between;align-items:center;padding:16px 0;border-top:1px solid #dfece6}.skill-review-list li>div{min-width:0;overflow-wrap:anywhere}.skill-review-list small{display:block;margin:5px 0;color:#677b74}.skill-review-list button{flex-shrink:0;min-height:48px}.skill-review-status{display:inline-block;font-size:12px;padding:4px 9px;border-radius:8px;background:#f5eee2;color:#6a553c}.skill-review-status.needs_review{background:#fae8f1;color:#8a3e64}.skill-review-status.improving{background:#dff4ed;color:#235e51}@media(max-width:400px){.skill-review-list li{align-items:flex-start;flex-direction:column}.review-support{padding:13px}.skill-review-list button{align-self:flex-end}}
/* Structured set answers: diagrams and equivalent touch/keyboard controls. */
.sets-visual{margin:14px 0;min-width:0}.sets-visual svg{display:block;width:100%;max-width:100%;height:auto}.sets-visual table{width:100%;border-collapse:collapse;font-size:.9rem}.sets-visual td,.sets-visual th{padding:7px;border-bottom:1px solid var(--line,#d7e6e2);text-align:left}.set-selection{border:0;padding:0;margin:12px 0;min-width:0}.set-selection legend{font-weight:750;margin-bottom:10px;line-height:1.6}.set-options{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(135px,100%),1fr));gap:9px}.set-option{display:flex;align-items:center;gap:7px;min-height:48px;padding:12px;border:2px solid #d6e8e3;border-radius:12px;background:#fff;color:var(--ink,#293f3b);text-align:left;line-height:1.6;overflow-wrap:anywhere}.set-option[aria-pressed=true],.set-empty[aria-pressed=true]{border-color:var(--teal,#2bb4aa);background:#e8f8f3}.set-option-check{opacity:0;flex:none;color:#157b73;font-weight:900}.set-option[aria-pressed=true] .set-option-check{opacity:1}.set-option:focus-visible,.set-empty:focus-visible,[data-set-region]:focus-visible{outline:3px solid #de7391;outline-offset:3px}.set-empty{width:100%;margin-top:8px;min-height:48px}.set-selection-summary{font-size:.9rem;line-height:1.7;color:#41645b}.set-answer-form [type=hidden]{display:none}.sets-visual [data-set-region]{cursor:pointer}.sets-visual [data-set-region]:focus{outline:2px solid #dd7292}.set-answer-form .answer-submit{width:100%;min-height:50px}.sets-visual .sets-alt{overflow-wrap:anywhere}

/* v30: modes have explicit names/icons and scoped surfaces, never sticky overlays. */
.lesson.learn-view,.lesson.practice-view,.lesson.assessment-view{min-width:0;box-sizing:border-box}
.lesson .mode-banner{display:flex;align-items:center;gap:12px;padding:14px 16px;margin:0 0 18px;border:1px solid;border-left-width:5px;border-radius:16px;text-align:left;min-width:0;position:static}
.lesson .mode-banner>div{min-width:0;flex:1;overflow-wrap:anywhere}
.lesson .mode-banner strong{display:block;font-size:20px;line-height:1.45;font-weight:800;letter-spacing:0}
.lesson .mode-banner span{display:block;margin-top:2px;font-size:14px;line-height:1.65}
.lesson .mode-icon{display:block;flex:0 0 38px;width:38px;height:38px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
.lesson .mode-learn{background:#e8f5ed;border-color:#80b9a8;color:#245b4d}
.lesson .mode-practice{background:#fff0f5;border-color:#cc7d9e;color:#79334f}
.lesson .mode-assessment{background:#edf0f7;border-color:#929fbb;color:#344563}
.lesson.learn-view{padding:22px;background:#fffdf3;border:1px solid #dedfc9;border-radius:23px;box-shadow:0 4px 18px #37544708}
.learn-view .learn-topic{font-size:28px;line-height:1.5;margin:16px 0 8px;letter-spacing:0;color:#254a42;overflow-wrap:anywhere}
.learn-view .learn-intro{font-size:15px;line-height:1.8;color:#435f54;margin:0 0 18px}
.learn-view .learn-outline{border:1px solid #c2d9c7;background:#f4f8ee;border-radius:13px;margin:16px 0 23px;min-width:0}
.learn-view .learn-outline>summary{min-height:48px;padding:12px 15px;box-sizing:border-box;cursor:pointer;font-size:15px;line-height:1.65;font-weight:750;color:#345a4c;overflow-wrap:anywhere}
.learn-view .learn-outline>summary::marker{color:#287769}
.learn-view .learn-outline>summary:focus-visible{outline:3px solid #b94e82;outline-offset:3px;border-radius:12px}
.learn-view .learn-outline .learn-chapters{margin:0;padding:0 12px 12px;gap:8px;min-width:0}
.learn-view .learn-outline .learn-chapters button{min-height:46px;line-height:1.65;color:#31594e;background:#fffdf6;border-color:#b6ccbc}
.learn-view .learn-outline .learn-chapters .chapter-active{color:#174c40;background:#d9eee0;border-color:#267c67}
.learn-view .learn-section-title{font-size:23px;line-height:1.55;color:#254a42;margin:24px 0 12px;overflow-wrap:anywhere}
.learn-view .learn-concept-heading{font-size:16px;line-height:1.6;font-weight:800;color:#28594a;margin:0 0 7px}
.learn-view .learn-concept{background:#edf6eb;border:1px solid #c6deca;border-left:4px solid #478d72;color:#34574a;font-size:15px;line-height:1.85;padding:18px;border-radius:4px 15px 15px 4px}
.learn-view .learn-concept p{margin:6px 0;overflow-wrap:anywhere}
.learn-view .learn-example{background:#fffef9;border-color:#d4d7bd;box-shadow:0 3px 0 #e9e7d6}
.learn-view .learn-guided{background:#f2faf5;border-color:#9fc9b4}
.learn-view .learn-example,.learn-view .learn-guided{min-width:0}
.learn-view .learn-steps{color:#385a4c}
.learn-view .learn-actions{padding-top:17px;border-top:1px solid #c9d8c8}
.learn-view .primary{background:#23786a;border-color:#23786a;color:#fff}
.learn-view .primary:hover{background:#1b6256;border-color:#1b6256}
.practice-view .lesson-context,.assessment-view .lesson-context{color:#445d56;line-height:1.75}
.practice-view .lessonhead,.assessment-view .lessonhead{gap:10px;flex-wrap:wrap;line-height:1.65}
.practice-view .lessonhead>span,.assessment-view .lessonhead>span{color:#3b554c;overflow-wrap:anywhere}
.practice-view .progressbar{background:#e9dedf;height:8px}
.practice-view .progressbar i{background:#b64a7b}
.practice-view .questioncard{border:1px solid #ddbfcd;border-top:4px solid #bc5984;background:#fff;box-shadow:0 5px 18px #663c4d08;min-height:0;margin-top:18px}
.practice-view .questionbadge{background:#fcecf2;color:#7c3554;border-color:#e1b2c6}
.practice-view .primary{background:#9f3865;border-color:#9f3865;color:#fff}
.practice-view .primary:hover{background:#822c53;border-color:#822c53}
.practice-view .question-review{padding-bottom:12px;border-bottom:1px dashed #d6dfd8}
.assessment-view .questioncard{border-color:#bbc5d6;border-top:4px solid #7284a5;background:#fff;min-height:0;margin-top:18px}
.assessment-view .primary{background:#445a7e;border-color:#445a7e;color:#fff}
.assessment-view .primary:hover{background:#344765;border-color:#344765}
@media(max-width:520px){.lesson.learn-view{padding:16px 13px;border-radius:18px}.lesson .mode-banner{padding:12px;gap:10px;margin-bottom:15px;border-radius:13px}.lesson .mode-banner strong{font-size:18px}.lesson .mode-banner span{font-size:13px}.lesson .mode-icon{flex-basis:32px;width:32px;height:32px}.learn-view .learn-topic{font-size:24px}.learn-view .learn-section-title{font-size:21px}.learn-view .learn-intro{font-size:14px}.learn-view .learn-concept{padding:14px;font-size:14px}.learn-view .learn-example,.learn-view .learn-guided{padding:17px 13px}.learn-view .learn-outline .learn-chapters{grid-template-columns:minmax(0,1fr)}.practice-view .questioncard,.assessment-view .questioncard{padding:23px 16px}}
@media(max-height:480px) and (orientation:landscape){.lesson .mode-banner{padding:9px 12px;margin-bottom:12px}.lesson .mode-icon{width:30px;height:30px;flex-basis:30px}}

/* New-question choices stay neutral even under a stationary pointer; keyboard focus remains visible. */
.choice:active{transform:none}
/* Practice identification stays compact above the question; text may wrap at larger text sizes. */
.practice-view .mode-banner.mode-practice{padding:9px 12px;gap:10px}
.practice-view .mode-practice .mode-icon{width:32px;height:32px;flex-basis:32px}
.practice-view .mode-practice>div{display:flex;align-items:baseline;flex-wrap:wrap;gap:2px 10px}
.practice-view .mode-practice strong{font-size:18px;line-height:1.5}
.practice-view .mode-practice span{margin:0;font-size:13px;line-height:1.65}
/* Answer feedback is explicit; suppress the browser's touch-only tap paint, not keyboard focus. */
.choice{-webkit-tap-highlight-color:transparent}

/* Structured givens → rule → task. Only prompt presentation changes; short sums stay large. */
.question.word{margin:20px 0 16px}
.question:has(.question-structured),.question:has(.question-prose){margin:18px 0 14px}
.question-layout.question-structured,.question-layout.question-prose{display:block;min-width:0;max-width:100%;font-size:20px;font-weight:500;line-height:1.75;text-align:left;color:#304c46;letter-spacing:0;white-space:normal;overflow-wrap:anywhere;word-break:normal}
.question-layout.question-structured{display:grid;gap:14px}
.question-layout .question-block{min-width:0;max-width:100%}
.question-layout .question-label{font-size:13px;font-weight:750;line-height:1.6;color:#4a665c;margin:0 0 4px}
.question-layout .question-given{font-size:1em;line-height:1.75;font-weight:500}
.question-layout .question-rule{padding:11px 13px;background:#f3f8f2;border:1px solid #d3e2d6;border-radius:12px;font-size:1em;font-weight:500;line-height:1.8;white-space:normal;overflow-wrap:anywhere;word-break:normal}
.question-layout .question-task{font-size:1em;font-weight:750;line-height:1.65;color:#2b4941;padding-top:1px}
.question-layout .question-roster{white-space:normal;word-break:normal;overflow-wrap:anywhere}
.question-layout .question-item,.question-layout .question-token{display:inline-block;white-space:nowrap;max-width:100%;vertical-align:baseline}
.question-layout.question-prose .math-inline,.question-layout.question-structured .math-inline{font-size:1em;line-height:inherit;white-space:normal}
.question-layout .question-token .math-inline{white-space:nowrap}
.questioncard:has(.question-structured) .question-review,.questioncard:has(.question-prose) .question-review{margin-top:12px;margin-bottom:13px}
.questioncard:has(.question-structured) .answer-form .answer-help{margin-top:10px;margin-bottom:12px}
.learn-question{margin:12px 0 16px;min-width:0;max-width:100%;font-size:26px;line-height:1.8;overflow-wrap:anywhere;color:#304c46}
.learn-question .question-layout.question-prose,.learn-question .question-layout.question-structured{font-size:19px;line-height:1.8}
.learn-question .question-expression{font-size:inherit;text-align:left}
@media(max-width:520px){.question-layout.question-structured,.question-layout.question-prose{font-size:18px;line-height:1.75}.question-layout.question-structured{gap:12px}.question-layout .question-rule{padding:10px 11px}.question-layout .question-label{font-size:12px}.learn-question{font-size:24px}.learn-question .question-layout.question-prose,.learn-question .question-layout.question-structured{font-size:18px}.question.word{margin:18px 0 14px}}

/* Every lesson is selectable. Progress labels are descriptive, never locks. */
.node-progress-summary{margin:8px 0 18px;color:var(--navy);font-size:14px;line-height:1.6}.node-progress-summary small{display:block;color:#60706d;font-size:12px}.node-progress-label{position:absolute;top:64px;left:50%;transform:translateX(-50%);width:max-content;max-width:100px;white-space:normal;overflow-wrap:anywhere;padding:3px 9px;border:1px solid #dce5df;border-radius:12px;background:#fffef8;color:#52605c;font-size:11px;font-weight:700;line-height:1.4}.isometric-region .node.not_started .nodebutton{background:#fffdf6;color:#344d48;border-color:#d6e5db;box-shadow:0 6px 0 #9bb8a9,0 0 0 5px #ffffff55}.isometric-region .node.in_progress .nodebutton{background:#e75284;color:white;border-color:#ffe1e7}.node.in_progress .node-progress-label{background:#fff0f6;border-color:#edb6cb;color:#96294f}.node.completed .node-progress-label{background:#e6f5ee;color:#245e53}.detail-free-choice{padding:10px 12px;background:#f0f8f4;border-radius:10px}.isometric-region .node.completed .nodebutton{background:#378679;border-color:#cbefe0;box-shadow:0 6px 0 #205a53}@media(max-width:600px){.node-progress-label{top:57px;font-size:10px;padding:3px 7px}.node-progress-summary{font-size:13px}}

.legacy-pending{padding:16px;border:1px solid #d9e7df;border-radius:14px;background:#fffef8;margin:12px 0}.legacy-pending .actions{flex-wrap:wrap}.legacy-pending button{white-space:normal;min-height:44px}

/* The end-of-set destination is chosen explicitly, never automatically. */
.set-completion-nav{margin:22px 0 16px;padding:18px;border:1px solid #cde5dc;border-radius:18px;background:#f0f8f3;text-align:left}.set-completion-nav h2{margin:0 0 5px;font-size:19px;color:var(--navy)}.set-completion-nav p{margin:6px 0 13px;font-size:13px;line-height:1.6;color:#526961}.completion-destinations{display:grid;grid-template-columns:minmax(0,1.5fr) minmax(0,1fr);gap:10px}.completion-destinations button{min-height:56px;white-space:normal;line-height:1.5;overflow-wrap:anywhere}.completion-next{text-align:left;display:flex;flex-direction:column;gap:3px}.completion-next strong{font-size:16px}.completion-next>span{font-size:13px;font-weight:500}.set-completion-nav .final-map-note{padding:8px 10px;background:#fffdf4;border-radius:10px}.summary-secondary{justify-content:center;flex-wrap:wrap;margin-top:12px}.summary-secondary button{white-space:normal;min-height:44px}@media(max-width:600px){.set-completion-nav{padding:14px}.completion-destinations{grid-template-columns:minmax(0,1fr)}.completion-next strong{font-size:15px}.summary-secondary{gap:8px}}

.completion-destinations .primary{background:#b33261;box-shadow:0 3px 0 #8d2a50}

/* v36: exercise focus is a real compact shell, not hidden duplicate navigation. */
.focus-shell{max-width:900px;margin:0 auto;padding:12px 24px max(28px,env(safe-area-inset-bottom));min-width:0}.focus-toolbar{display:flex;align-items:center;justify-content:space-between;gap:12px;margin:0 0 12px}.focus-toolbar button{min-height:44px;padding:8px 12px}.focus-toolbar>span{font-size:12px;color:#4b635e}.focus-shell .lesson{margin:0 auto;max-width:780px}.focus-shell .lesson-context{margin:8px 0}.focus-shell .lessonhead{margin:10px 0;gap:8px}.focus-shell .questioncard{min-height:0;padding:24px;margin-top:14px}.focus-shell .question.word{margin-top:10px}.focus-shell .learn-view{padding-top:0}.focus-shell .focus-save-warning{margin:8px 0}.numeric-tools{display:flex;flex-wrap:wrap;gap:8px;align-items:center;margin:10px 0}.numeric-field-tools{display:flex;flex-wrap:wrap;gap:6px}.numeric-field-tools:empty{display:none}.numeric-tools button{min-height:44px;padding:8px 12px;border:1px solid #9bb9b0;border-radius:10px;background:#fff;color:#263d38;font-size:15px;font-weight:650}.numeric-tools button:focus-visible{outline:3px solid #176f61;outline-offset:2px}.focus-shell input{scroll-margin-block:20px}.focus-shell .answer-form{min-width:0}.focus-shell .answer-form input{max-width:100%}
@media(max-width:600px){.focus-shell{padding:8px 12px max(24px,env(safe-area-inset-bottom))}.focus-toolbar{margin-bottom:8px}.focus-toolbar>span{display:none}.focus-shell .questioncard{padding:18px 14px;margin-top:10px}.focus-shell .mode-banner{margin-top:0}.focus-shell .lesson-context{font-size:12px}.focus-shell .questionbadge{font-size:12px}.numeric-tools{gap:6px}.numeric-tools button{font-size:14px;padding:7px 10px}.focus-shell .answer-form input{font-size:max(20px,1em)}}
@media(max-height:500px){.focus-toolbar{margin-bottom:4px}.focus-shell{padding-top:4px}.focus-shell .mode-banner{margin-bottom:6px}.focus-shell .questioncard{margin-top:8px;padding-top:14px}}
.focus-shell .decimal-revision-notice{margin:8px 0 12px;padding:10px 12px;gap:10px;font-size:13px;line-height:1.55}.focus-shell .decimal-revision-notice p{margin:4px 0 0}.focus-shell .decimal-revision-notice button{min-height:44px;white-space:normal}

/* v38: predictable primary navigation, optional secondary destinations. */
.compact-main-nav{gap:8px}.compact-main-nav .navbutton{min-height:48px}.compact-main-nav .nav-resume{background:#e5f5ed;color:#155c4d}.more-nav{position:relative;margin-top:4px}.more-nav summary{list-style:none;cursor:pointer;user-select:none}.more-nav summary::-webkit-details-marker{display:none}.more-nav summary:focus-visible{outline:3px solid #df3d78;outline-offset:3px}.more-nav[open] summary{background:#e6f4ee}.more-menu{position:absolute;z-index:70;top:calc(100% + 6px);left:0;width:220px;max-width:calc(100vw - 24px);padding:8px;border:1px solid #b7cdc3;border-radius:14px;background:#fff;box-shadow:0 12px 30px #24463a26}.more-menu .navbutton{width:100%;text-align:left;margin:2px 0}.more-menu .navbutton span:last-child{font-size:14px}.more-menu .navbutton.active{font-weight:750;text-decoration:underline;text-underline-offset:4px}
@media(max-width:600px){.compact-main-nav{display:grid!important;grid-template-columns:repeat(4,minmax(0,1fr));align-items:stretch;gap:3px;padding:7px 8px max(7px,env(safe-area-inset-bottom))}.compact-main-nav>.navbutton,.compact-main-nav>.more-nav{min-width:0;margin:0}.compact-main-nav>.navbutton,.more-nav>summary{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:3px;padding:5px 2px;min-height:52px}.compact-main-nav>.navbutton>span:last-child,.more-nav>summary>span:last-child{font-size:11px;line-height:1.4;white-space:normal}.more-menu{top:auto;bottom:calc(100% + 12px);left:auto;right:0;width:228px}.more-menu .navbutton{display:flex;flex-direction:row;align-items:center;gap:12px;padding:10px 12px}.more-menu .navbutton span:first-child{font-size:20px}.more-menu .navbutton span:last-child{font-size:14px}.more-nav>summary{height:100%}}

/* v39: secondary navigation contains only personal learning data. */
.more-menu .navbutton:only-child{margin:0}.summary-secondary{justify-content:center}.set-completion-nav{margin-top:24px}.topright:empty{display:none}

/* Exact logarithm bases and indexed roots; presentation only. */
.math-logarithm{display:inline-flex;align-items:baseline;white-space:nowrap;gap:.06em}.math-log-base{font-size:.68em;line-height:1;position:relative;bottom:-.27em;margin-right:.12em}.math-log-base .math-frac{font-size:.9em}.math-nthroot .math-root-index{font-size:.6em;min-width:.65em}.math-nthroot{padding-left:.1em}
/* Focused Learn: instructional content, two exit actions, no application chrome. */
.learn-focus-shell{max-width:880px}.learn-focus-shell .learn-view{padding:22px 26px}.learn-navigation{display:flex;align-items:center;justify-content:space-between;gap:12px;margin:0 0 22px;flex-wrap:wrap}.learn-navigation button{min-height:46px;white-space:normal;text-align:center;font-size:16px;line-height:1.5}.learn-navigation .plain{color:#24666b;border:1px solid #b6d9d5;border-radius:12px;padding:10px 14px;background:#fff}.learn-reading-title{font-size:clamp(23px,3vw,30px);line-height:1.55;color:#293e45;margin:12px 0 20px;overflow-wrap:anywhere;letter-spacing:0}.learn-focus-shell .learn-outline{margin:0 0 22px}.learn-focus-shell .learn-concept-heading{font-size:19px;line-height:1.6;margin:18px 0 10px;color:#293e45}.learn-focus-shell .learn-concept{font-size:17px;line-height:1.8}.learn-focus-shell .learn-example,.learn-focus-shell .learn-guided{margin-top:18px}.learn-focus-shell .learn-guided{margin-bottom:0}.learn-focus-shell .focus-save-warning{font-size:14px;margin:8px 0}@media(max-width:520px){.learn-focus-shell .learn-view{padding:16px 13px}.learn-navigation{gap:8px;margin-bottom:18px}.learn-navigation button{font-size:15px;padding:9px 11px}.learn-reading-title{font-size:24px}.learn-focus-shell .learn-concept{font-size:16px}}@media(max-width:320px){.learn-navigation{align-items:stretch}.learn-navigation button{flex:1 1 130px}}

.learn-reading-mode{display:flex;align-items:center;gap:7px;margin:0 0 4px;color:#24666b;font-size:14px;font-weight:650;line-height:1.5}.learn-reading-mode+.learn-reading-title{margin-top:4px}

.chapter-review-links{margin:12px 0;padding:12px 14px;background:#f3f8f4;border:1px solid #d2e5df;border-radius:14px}.chapter-review-links summary{cursor:pointer;font-weight:650}.chapter-review-links p{font-size:.9rem;line-height:1.6;margin:10px 0}.chapter-review-actions{display:flex;flex-wrap:wrap;gap:8px}.chapter-review-actions button{white-space:normal;text-align:left;min-height:44px}

.triple-answer{display:grid;grid-template-columns:auto minmax(0,1fr);align-items:center;gap:10px 12px;max-width:520px;margin:14px auto}.triple-answer label{font-size:.95rem;font-weight:600}.triple-answer input{min-width:0;width:100%;min-height:48px;font:inherit;padding:10px;border:2px solid #bad7d4;border-radius:12px;background:#fff;color:#293438}.triple-answer input:focus-visible{outline:3px solid #e0a5c3;outline-offset:2px}

.math-vector{position:relative;display:inline-flex;padding-top:.35em;min-width:.55em;margin:0 .05em}.math-vector-arrow{position:absolute;top:-.2em;left:0;width:100%;font-size:.78em;line-height:1;text-align:center;font-style:normal}.math-norm{display:inline-flex;align-items:baseline;gap:.08em}

.math-indexed{display:inline-flex;align-items:baseline}.math-sub{font-size:.72em;position:relative;top:.22em;line-height:1}

.math-conjugate{display:inline-flex;border-top:1px solid currentColor;padding-top:.08em;margin-top:.08em;align-items:baseline}

.math-summation{display:inline-flex;align-items:center;gap:.16em;max-width:100%;vertical-align:middle}.math-sigma-stack{display:inline-flex;flex-direction:column;align-items:center;flex:none;line-height:1.1;padding:.1em}.math-sigma-symbol{font-size:1.6em;line-height:1}.math-sigma-upper,.math-sigma-lower{font-size:.65em;white-space:nowrap}.math-sigma-body{display:inline-flex;align-items:baseline;min-width:0}

/* Bounded presentation-only counting notation. */
.math-factorial{display:inline-flex;align-items:baseline;white-space:nowrap}.math-binomial{display:inline-flex;align-items:center;vertical-align:middle;gap:.08em}.math-binomial-stack{display:inline-flex;flex-direction:column;align-items:center;line-height:1.15;gap:.14em;padding:.08em}.math-binomial-paren{font-size:2.15em;font-weight:300;line-height:1}

.math-probability{display:inline-flex;align-items:baseline;flex-wrap:wrap;gap:.06em}.math-probability>.math-function-name{font-style:normal}

/* Calculus notation: bounded AST output, no symbolic evaluation. */
.math-limit,.math-integral{display:inline-flex;align-items:center;gap:.18em;max-width:100%;vertical-align:middle}.math-limit-stack,.math-integral-stack{display:inline-flex;flex-direction:column;align-items:center;flex-shrink:0;line-height:1.05}.math-limit-target{display:inline-flex;align-items:baseline;gap:.08em;font-size:.68em;white-space:nowrap}.math-limit-target sup{font-size:.8em}.math-limit-body,.math-integral-body{display:inline-flex;align-items:center;flex-wrap:wrap;min-width:0}.math-integral-symbol{font-family:Georgia,serif;font-size:1.85em;line-height:1}.math-integral-upper,.math-integral-lower{font-size:.65em;line-height:1.1}.math-differential{display:inline-flex;gap:.03em;white-space:nowrap;margin-left:.08em}.math-prime{display:inline-flex;align-items:baseline}

.math-overline{display:inline-flex;align-items:baseline;border-top:.065em solid currentColor;padding-top:.05em;line-height:1.15}

/* Keep the optional Learn-to-practice route visible after title focus/scroll. */
.learn-practice-entry{display:flex;align-items:center;gap:12px 18px;flex-wrap:wrap;margin:0 0 22px}.learn-practice-entry .primary{min-height:46px;font-size:16px;line-height:1.5;white-space:normal}.learn-practice-note{flex:1 1 260px;margin:0;color:#435f54;font-size:14px;line-height:1.7;overflow-wrap:anywhere}@media(max-width:520px){.learn-practice-entry{gap:8px}.learn-practice-entry .primary{width:100%}.learn-practice-note{font-size:13px}}

/* Read-only Learn: a scrollable visual lesson, separate from all answer controls. */
.learn-focus-shell{max-width:980px}.learn-focus-shell .learn-reading-view{max-width:880px;padding:28px 34px 34px;background:#fff;border:1px solid #dae6e1;border-radius:24px}.learn-reading-header{display:block;height:auto;min-height:0;position:static;border:0;background:transparent;padding:8px 0 6px}.learn-reading-header .learn-reading-title{font-size:clamp(27px,4vw,38px);line-height:1.5;letter-spacing:-.025em;margin:8px 0 14px;color:#183f3b}.learn-reading-intro{margin:0 0 22px;font-size:16px;line-height:1.9;color:#526a65}.learn-reading-view .learn-reading-mode{font-size:13px;letter-spacing:.02em;color:#356c65}.learn-reading-path{display:flex;align-items:center;justify-content:space-between;gap:9px;flex-wrap:wrap;border-block:1px solid #dbe9e3;padding:18px 0;margin:0 0 32px;color:#46675e;font-size:13px;line-height:1.7}.learn-reading-path span{display:flex;align-items:center;gap:7px}.learn-reading-path b{background:#e6f3ee;color:#286456;display:grid;place-items:center;min-width:27px;height:27px;border-radius:50%;font-size:13px}.learn-small-label{display:block;color:#52796f;font-size:12px;font-weight:750;letter-spacing:.035em;line-height:1.8;margin:0 0 7px}.learn-concept-block{margin:0 0 32px;border-left:4px solid #70aa97;padding:3px 0 3px 22px}.learn-reading-view .learn-concept-heading{font-size:23px;color:#234d42;margin:0 0 10px;line-height:1.6}.learn-reading-view .learn-concept{background:none;padding:0;margin:0;border-radius:0;color:#35584d;font-size:18px;line-height:2}.learn-reading-view .learn-example{margin:0 0 32px;padding:26px;border-radius:19px;border:1px solid #d4e3dc;background:#fcfefc;box-shadow:none;min-width:0}.learn-reading-view .learn-second-example{background:#fffefd;border-color:#e5dfd0}.learn-section-heading{display:flex;align-items:flex-start;gap:14px;margin-bottom:22px}.learn-section-number{font-family:Georgia,serif;font-size:30px;line-height:1.2;color:#559080;background:#e8f3ed;border-radius:13px;padding:10px;flex:0 0 auto}.learn-second-example .learn-section-number{color:#9b7a45;background:#f4efe2}.learn-reading-view .learn-section-heading h2{font-size:23px;line-height:1.6;color:#244c41;margin:2px 0 0}.learn-reading-view .panel-step{margin:0;font-size:12px;color:#5b7e70;line-height:1.7}.learn-example-given{min-width:0;max-width:100%;overflow-x:auto;padding:17px 19px;background:#fff;border:1px solid #e1e9e3;border-radius:13px;margin:0 0 18px}.learn-reading-view .learn-question{margin:3px 0;font-size:27px;line-height:1.9;color:#263f39}.learn-reading-view .learn-question .question-prose,.learn-reading-view .learn-question .question-structured{font-size:18px;line-height:1.9}.learn-diagram{min-width:0;max-width:100%;margin:20px 0;overflow-x:auto;overscroll-behavior-x:contain;border-radius:14px}.learn-diagram>figure,.learn-diagram>div{margin-inline:0}.learn-diagram svg{max-width:100%;height:auto}.learn-diagram .learning-visual{padding:25px 20px}.learn-reading-view .counting-dots{max-width:500px;gap:10px}.learn-reading-view .count-dot{max-width:38px}.learn-visual-guide{border-left:3px solid #7bb7a6;background:#eff7f3;border-radius:0 12px 12px 0;padding:15px 18px;margin:20px 0 26px;color:#325c4f}.learn-reading-view h3{font-size:16px;line-height:1.8;margin:0 0 8px;color:#32594c}.learn-visual-guide ul{margin:0;padding-left:20px;font-size:15px;line-height:1.9}.learn-visual-guide li+li{margin-top:6px}.learn-reading-view .learn-reasoning-heading{margin:26px 0 12px;font-size:17px}.learn-reading-view .learn-reasoning-flow{list-style:none;counter-reset:reason;margin:0;padding:0;color:#344f46;font-size:16px;line-height:1.95}.learn-reading-view .learn-reasoning-flow>li{counter-increment:reason;position:relative;padding:0 0 19px 43px;margin:0;min-width:0}.learn-reasoning-flow>li::before{content:counter(reason);position:absolute;left:0;top:10px;display:grid;place-items:center;width:29px;height:29px;border:1px solid #a9c9bb;border-radius:50%;color:#3d6d5c;background:#fff;font-size:13px;font-weight:700;z-index:1}.learn-reasoning-flow>li:not(:last-child)::after{content:'↓';position:absolute;left:7px;top:42px;bottom:0;color:#8eb5a6;font-size:17px;line-height:1.5}.learn-reasoning-flow>li>div{padding:13px 16px;background:#fff;border:1px solid #dfebe4;border-radius:12px;min-width:0;overflow-wrap:anywhere;overflow-x:auto}.learn-example-answer{margin:8px 0 0;padding:14px 19px;background:#e6f2eb;border:1px solid #c6dfd0;border-radius:13px;display:flex;align-items:center;gap:12px 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