:root{color-scheme:light;--ink:#212a25;--muted:#596357;--paper:#fffdf7;--sand:#f3f0e5;--green:#355f4c;--line:#d5d9cb;font-family:system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:var(--ink);background:var(--sand)}
*{box-sizing:border-box}body{margin:0}a{color:var(--green);text-underline-offset:4px}button,input,select,textarea{font:inherit}button,a,input,select,textarea{touch-action:manipulation}button{cursor:pointer;border:1px solid var(--line);border-radius:10px;min-height:44px;padding:10px 14px;background:var(--paper);color:var(--ink);font-weight:650}button:hover{border-color:var(--green);background:#eaf0e3}button[aria-pressed=true],.panel-list button[aria-current=true]{background:var(--green);border-color:var(--green);color:#fff}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible,summary:focus-visible{outline:3px solid 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#27322308}.book-picker{display:flex;background:#e6eadc;padding:12px;gap:12px}.book-picker button{flex:1;text-align:left;font-size:1.1rem;padding:16px}.book-picker button span{font-size:.75rem;margin-right:16px}.book-toolbar{display:flex;align-items:center;flex-wrap:wrap;gap:18px;padding:24px 28px;border-bottom:1px solid var(--line)}.book-toolbar h2{margin:0 auto 0 0}.toggles{display:flex;gap:6px}.book-layout{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);align-items:start}.sheet-map{padding:28px;background:#eeece1}.sheet-paper{position:relative;box-shadow:0 7px 25px #252e241a;background:white;container-type:inline-size}.sheet-paper img{width:100%;height:auto;display:block}.sheet-overlays{position:absolute;inset:0}.sheet-hotspot{position:absolute;min-height:0;padding:0;border:2px solid transparent;border-radius:8px;background:color-mix(in srgb,var(--shade) 28%,transparent);mix-blend-mode:multiply}.sheet-hotspot:hover{background:color-mix(in srgb,var(--shade) 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14px;background:#e8f0e0;font-size:.92rem}.error{color:#943b20;font-size:.85rem;min-height:0}.error:empty{display:none}.step-explanation{background:#fff;border:1px solid var(--line);border-radius:10px;padding:16px}.step-explanation p:last-child{margin-bottom:0}.equation{display:flex;align-items:center;justify-content:center;gap:8px;flex-wrap:wrap;font-size:1.2rem;padding:20px 0;overflow-wrap:anywhere}.fraction{display:inline-flex;flex-direction:column;text-align:center;line-height:1.5}.fraction>span:first-child{border-bottom:2px solid var(--ink)}.cancelled{text-decoration:line-through;text-decoration-color:#a34534;text-decoration-thickness:2px}.prefix-table{display:flex;flex-wrap:wrap;gap:6px;margin-top:14px}.prefix-table>span{display:flex;flex-direction:column;background:#fff;border:1px solid var(--line);border-radius:7px;padding:9px;font-size:.8rem;flex:1;min-width:65px}.reference{border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:10px 0;margin:20px 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@media(max-width:540px){main{padding:0 12px}.book-header{padding:18px 16px}.brand{display:none}.book-intro{padding:24px 8px}.book-picker{gap:6px;padding:8px}.book-picker button{font-size:.9rem;padding:12px}.book-picker button span{display:block;margin:0 0 4px}.book-toolbar{gap:12px;padding:18px 14px}.book-toolbar h2{width:100%}.toggles{flex-wrap:wrap}.toggles button{font-size:.85rem;padding:10px}.sheet-map{padding:16px 12px}.explore-panel{padding:24px 14px}.model-card{padding:15px 12px}.number-row{grid-template-columns:1fr 1fr}.number-row>label:first-child{grid-column:1/-1}.unit-buttons{gap:5px}.unit-buttons button{min-width:40px}.library-grid{grid-template-columns:1fr}.save-bar{padding:22px 16px}.library-grid article{padding:20px}.equation{font-size:1rem}.sheet-hotspot span{font-size:9px}}
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@media print{.book-header,.book-intro,#measurement-book,footer{display:none}.paper-library{padding:0}.library-grid{display:block}.library-grid article{break-inside:avoid;margin-bottom:20px}.paper-library a{color:#000}}