:root{font-family:Inter,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;color:#253c35;background:#f3f5f1;font-synthesis:none;--green:#235d4e;--muted:#64776e;--line:#dfe6df;--soft:#eaf1e9;--white:#fff;--radius:16px}
*{box-sizing:border-box}body{margin:0}button,a{-webkit-tap-highlight-color:transparent}button{font:inherit;color:inherit;cursor:pointer;touch-action:manipulation}button:disabled{cursor:default;opacity:.42}button:focus-visible,a:focus-visible,summary:focus-visible,canvas:focus-visible{outline:3px solid #ba892d;outline-offset:3px}button{min-height:44px;border:1px solid var(--line);background:#fff;border-radius:9px}button:hover{background:#f0f5ef}button[aria-pressed=true]{background:var(--soft);border-color:#b2cbb9;color:var(--green)}[hidden]{display:none!important}a{color:var(--green)}
.app-shell{display:grid;grid-template-columns:214px minmax(0,1fr);height:100vh;height:100dvh;min-height:640px;padding:env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left)}
.sidebar{padding:32px 20px 22px;border-right:1px solid var(--line);display:flex;flex-direction:column;background:#f9faf6;overflow:auto}.brand{text-decoration:none;display:flex;align-items:center;gap:10px;font-size:19px;font-weight:750;white-space:nowrap}.brand-mark{width:34px;height:38px;border-radius:10px;background:var(--green);color:white;display:grid;place-items:center;font-size:32px;font-weight:400}.brand small{font-size:8px;display:block;letter-spacing:1.6px;margin-top:6px;font-weight:600;color:#75867d}.menu-heading{display:flex;justify-content:space-between;font-size:12px;color:var(--muted);margin:48px 8px 17px}.menu-heading span{font-size:10px;letter-spacing:1px}#crystal-menu{display:flex;flex-direction:column;gap:10px}.crystal-option{display:grid;grid-template-columns:1fr auto;text-align:left;padding:17px 16px;border:1px solid transparent;background:transparent;position:relative;min-height:80px}.crystal-option .formula{font-size:23px;font-weight:680;line-height:1.2}.crystal-option .crystal-description{font-size:12px;color:var(--muted);display:block;margin-top:7px}.crystal-option .menu-number{font-size:10px;color:#86968d;align-self:center}.crystal-option[aria-current=true]{background:var(--soft);border-color:#ccddce;color:var(--green)}.crystal-option[aria-current=true]:before{content:"";position:absolute;left:-1px;top:22px;bottom:22px;width:3px;background:var(--green);border-radius:3px}.sidebar-foot{margin-top:auto;padding:30px 8px 0}.edition{font-size:11px;letter-spacing:1px;color:#7b8b81}.sidebar-foot p{line-height:1.9;font-size:15px;color:#536c5e;margin:15px 0 24px}.help-button{display:flex;justify-content:space-between;width:100%;background:none;border:0;padding:0;font-size:12px;border-top:1px solid var(--line);border-radius:0}.offline-status{font-size:10px;display:block;color:#627b69;line-height:1.6;margin-top:5px}
.workspace{min-width:0;min-height:0;display:flex;flex-direction:column;padding:0 30px 12px;overflow:auto}.topbar{min-height:66px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);color:var(--muted);font-size:12px}.slash{margin:0 13px;color:#a1ada5}.version{display:flex;align-items:center;gap:8px;font-size:11px}.version i,.live-dot{height:6px;width:6px;border-radius:50%;background:#69896b;display:inline-block}.lesson-head{display:flex;align-items:center;justify-content:space-between;padding:25px 0 22px;gap:15px}.eyebrow{font-size:10px;color:#809080;letter-spacing:3px;margin-bottom:9px}h1{font-size:34px;margin:0;font-weight:650;line-height:1.15;letter-spacing:-.8px}#crystal-subtitle{font-size:16px;color:var(--muted);font-weight:450;letter-spacing:0;margin-left:16px}.structure-badge{font-size:11px;border:1px solid #d4ded1;padding:9px 12px;border-radius:5px;white-space:nowrap}
.scene-layout{display:grid;grid-template-columns:minmax(0,1fr) 252px;gap:20px;min-height:310px;flex:1}.scene-column{min-width:0;display:flex;flex-direction:column;min-height:0}.viewer-shell{border:1px solid var(--line);border-radius:var(--radius);background:#f7f9f7;position:relative;display:flex;flex-direction:column;flex:1;min-height:290px;overflow:hidden}.scene-caption{display:flex;align-items:center;gap:8px;padding:18px 20px 0;font-size:11px;z-index:1}.coordinate-note{margin-left:auto;font-family:Consolas,monospace;font-size:10px;color:#7b8a82}.viewer{position:relative;flex:1;min-height:210px;overflow:hidden;isolation:isolate}.viewer canvas{display:block;width:100%;height:100%;touch-action:none;cursor:grab;position:absolute;inset:0}.viewer canvas:active{cursor:grabbing}.label-layer{position:absolute;inset:0;pointer-events:none;overflow:hidden}.atom-label,.axis-label{position:absolute;top:0;left:0;will-change:transform;font-size:12px;font-weight:700;white-space:nowrap;background:#fffffff0;padding:3px 6px;border-radius:5px;box-shadow:0 1px 4px #1e3a2420;color:#30493e}.axis-label{font-size:13px;background:transparent;box-shadow:none;padding:0}.scene-footer{display:flex;align-items:center;justify-content:space-between;padding:2px 16px 10px;gap:8px;font-size:10px;color:#7d8b83}.compact-button{font-size:11px;padding:0 13px;min-height:44px;border-radius:7px}.legend-bar{display:flex;align-items:center;gap:12px;padding:10px 2px 0;flex-wrap:wrap;min-height:57px}.legend-title{font-size:11px;color:var(--muted)}.legend{display:flex;gap:8px;flex-wrap:wrap}.legend button{min-height:44px;padding:0 11px;border-color:transparent;background:transparent;font-size:13px;display:flex;align-items:center;gap:8px}.legend button[aria-pressed=false]{opacity:.5;text-decoration:line-through}.element-dot{display:inline-block;width:12px;height:12px;border-radius:50%;background:var(--element-color);border:1px solid #0000000d;flex-shrink:0}.legend-hint{font-size:10px;color:#819085;margin-left:auto}.info-rail{display:flex;flex-direction:column;gap:13px;overflow:auto;min-height:0;padding-bottom:2px}.card{padding:20px;background:#fff;border:1px solid var(--line);border-radius:var(--radius)}.card-kicker{color:#7c8d80;font-size:10px;letter-spacing:1.4px;margin-bottom:10px}.card h2{font-size:17px;margin:0 0 13px;font-weight:650}.card p{font-size:12px;color:var(--muted);line-height:1.85;margin:0}.atom-card{position:relative;min-height:160px;background:#eef3eb}.atom-card p{max-width:180px}.tap-hint{position:absolute;right:16px;bottom:10px;font-size:42px;font-weight:300;color:#c0d0bd}.atom-properties{display:grid;grid-template-columns:auto 1fr;gap:8px 12px;font-size:12px;margin:0}.atom-properties dt{color:var(--muted)}.atom-properties dd{margin:0;text-align:right;font-weight:550}.atom-properties .coordinate-value{font-family:Consolas,monospace;font-size:12px}.clear-selection{position:absolute;top:7px;right:7px;border:0;background:transparent;min-width:44px;font-size:21px;color:var(--muted)}.summary-card{margin-top:auto}.element-summary-row{padding:13px 0;border-top:1px solid #e8ece5}.element-summary-name{display:flex;align-items:center;gap:8px;font-size:15px;font-weight:650}.element-summary-name strong{margin-left:auto;font-size:20px}.element-summary-name strong small{font-size:10px;color:var(--muted);font-weight:400;margin-left:4px}.element-summary-row p{margin-top:5px;font-size:11px}.structure-note{border-top:1px solid #e8ece5;padding-top:12px!important}.source-details{font-size:10px;color:#78897c;margin-top:12px}.source-details summary{cursor:pointer;min-height:30px;display:list-item}.source-details a{display:block;font-size:11px;margin:5px 0}.source-details p{font-size:10px;margin-top:8px}
.teaching-toolbar{display:flex;align-items:center;justify-content:space-around;padding:8px;background:#fff;border:1px solid var(--line);border-radius:12px;gap:5px;flex-shrink:0;margin-top:18px}.teaching-toolbar button{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:6px;flex:1;min-height:65px;border-color:transparent;white-space:nowrap;font-size:11px;padding:7px 8px}.control-icon{font-size:24px;line-height:26px;font-weight:400}.text-icon{font-size:20px}.toolbar-divider{height:32px;width:1px;background:var(--line);margin:0 5px}.workspace-note{font-size:9px;color:#7c8d7e;padding-top:10px;flex-shrink:0}.workspace-note>span:not(.note-right){margin:0 8px}.note-right{float:right}
.count-panel{background:#f9fbf7;border:1px solid #cbdcc9;border-radius:12px;padding:14px 18px;margin-top:10px;flex-shrink:0}.count-heading{display:flex;align-items:center;justify-content:space-between;gap:12px}.count-heading strong{font-size:14px}.count-heading span{font-size:10px;color:var(--muted);margin-left:12px}.site-filters{display:flex;gap:5px;flex-wrap:wrap}.site-filters button{font-size:11px;padding:0 12px}.count-results{display:flex;gap:12px;margin-top:12px;flex-wrap:wrap}.count-result{background:white;border:1px solid var(--line);border-radius:8px;padding:10px 14px;flex:1;min-width:160px}.count-result header{display:flex;align-items:center;gap:8px;font-size:13px;font-weight:650;margin-bottom:6px}.count-equation{font-size:14px;line-height:1.8;font-variant-numeric:tabular-nums}.count-equation small{font-size:10px;color:var(--muted);margin-right:10px}.count-total{font-size:12px;font-weight:650;color:var(--green);margin-top:4px}.count-note{font-size:10px;color:var(--muted);line-height:1.6;margin:9px 0 0}.loading,.viewer-error{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;z-index:10;color:var(--muted);background:#f7f9f7;font-size:13px;padding:24px;text-align:center}.viewer-error{color:#963c32;background:#fff6f0;z-index:12}.toast{position:fixed;bottom:calc(24px + env(safe-area-inset-bottom));left:50%;transform:translateX(-50%);max-width:min(90vw,580px);border-radius:10px;padding:14px 20px;z-index:100;background:#253e34;color:white;box-shadow:0 4px 20px #1b342326;font-size:13px;line-height:1.7}
dialog{border:1px solid var(--line);border-radius:18px;max-width:580px;width:calc(100% - 32px);max-height:85vh;padding:0;color:inherit;background:#fcfdf9;box-shadow:0 18px 90px #1a332d30}dialog::backdrop{background:#1b302a55}.dialog-head{display:flex;align-items:center;justify-content:space-between;padding:18px 24px;border-bottom:1px solid var(--line);position:sticky;top:0;background:#fcfdf9}.dialog-head h2{font-size:20px;margin:0}.dialog-head button{border:0;background:none;min-width:44px;font-size:25px}.help-content{padding:0 24px 22px}.help-content h3{font-size:15px;margin:24px 0 10px}.help-content p{font-size:13px;line-height:1.9;color:var(--muted)}.presentation .sidebar,.presentation .topbar,.presentation .workspace-note{display:none}.app-shell.presentation{grid-template-columns:1fr}
@media(min-width:1500px){.workspace{padding-left:46px;padding-right:46px}.scene-layout{grid-template-columns:minmax(0,1fr) 285px;gap:28px}.lesson-head{padding:30px 0}.card{padding:24px}.card p{font-size:13px}.teaching-toolbar button{font-size:13px}}
@media(max-width:1150px){.app-shell{grid-template-columns:180px minmax(0,1fr)}.sidebar{padding:25px 12px 16px}.brand{font-size:16px;gap:7px}.brand small{font-size:7px;letter-spacing:1.2px}.brand-mark{width:29px;height:34px}.workspace{padding:0 20px 10px}.scene-layout{grid-template-columns:minmax(0,1fr) 215px;gap:14px}.card{padding:16px}.legend-hint{display:none}.count-heading{align-items:flex-start;flex-direction:column}.count-heading span{margin-left:10px}}
@media(max-width:900px){.app-shell{grid-template-columns:150px minmax(0,1fr)}.brand-mark{display:none}.menu-heading{margin-top:30px}.crystal-option{padding:15px 11px}.workspace{padding:0 14px 10px}.scene-layout{grid-template-columns:minmax(0,1fr) 185px;gap:10px}.card{padding:13px}.card h2{font-size:15px}.card p{font-size:11px}.lesson-head{padding:18px 0}h1{font-size:29px}#crystal-subtitle{font-size:13px;margin-left:9px}.structure-badge{font-size:10px;padding:7px}.teaching-toolbar button{font-size:10px;padding:6px 3px}.toolbar-divider{margin:0 2px}.coordinate-note{display:none}.scene-caption{padding:13px 12px 0}.scene-footer{padding:0 8px 8px}.scene-footer>span{font-size:9px}.legend-bar{gap:5px}.atom-properties{grid-template-columns:1fr;gap:4px}.atom-properties dd{text-align:left;margin-bottom:3px}}
@media(max-width:700px) and (orientation:portrait){.app-shell{display:flex;flex-direction:column;height:auto;min-height:100dvh}.sidebar{padding:15px 16px 10px;border-right:0;border-bottom:1px solid var(--line);overflow:visible}.brand-mark{display:grid;width:27px;height:29px;font-size:25px}.brand small{display:none}.brand{font-size:16px}.menu-heading,.sidebar-foot{display:none}#crystal-menu{flex-direction:row;gap:5px;margin-top:12px}.crystal-option{flex:1;min-height:56px;padding:8px;text-align:center;display:block;background:#f3f5ef}.crystal-option .formula{font-size:17px}.crystal-option .crystal-description{font-size:9px;margin-top:5px}.menu-number{display:none}.crystal-option[aria-current=true]:before{display:none}.workspace{overflow:visible;padding:0 13px 13px}.topbar{min-height:42px;font-size:10px}.version{font-size:9px}.lesson-head{padding:17px 0}.eyebrow{font-size:8px}h1{font-size:28px}#crystal-subtitle{font-size:12px}.structure-badge{font-size:9px;white-space:normal;max-width:110px;line-height:1.6}.scene-layout{display:flex;flex-direction:column;gap:12px}.viewer-shell{height:360px;flex:none;min-height:0}.viewer{min-height:0}.info-rail{display:grid;grid-template-columns:1fr 1fr;align-items:start;overflow:visible;gap:10px}.summary-card{margin-top:0}.atom-card{min-height:175px}.card{border-radius:12px}.card h2{font-size:14px}.legend-bar{padding-top:5px;min-height:50px}.scene-caption .coordinate-note{display:block}.teaching-toolbar{position:sticky;bottom:env(safe-area-inset-bottom);z-index:20;box-shadow:0 4px 15px #253c3514;margin-top:12px;padding:5px 3px;gap:0}.teaching-toolbar button{font-size:9px;min-height:60px;padding:4px 1px;gap:4px}.control-icon{font-size:21px}.text-icon{font-size:17px}.toolbar-divider{display:none}.note-right{display:none}.count-panel{padding:12px}.site-filters{gap:4px}.site-filters button{padding:0 9px;font-size:10px}.count-results{gap:8px}.count-result{min-width:130px;padding:9px}.count-equation{font-size:13px}.count-heading span{font-size:9px}.workspace-note{font-size:8px}}
@media(max-height:600px) and (orientation:landscape){.app-shell{min-height:100dvh;height:auto}.sidebar{padding-top:16px;position:sticky;top:0;max-height:100dvh}.brand small,.sidebar-foot p,.edition{display:none}.menu-heading{margin-top:20px;margin-bottom:8px}.crystal-option{min-height:59px;padding:10px}.crystal-option .formula{font-size:20px}.sidebar-foot{padding-top:12px}.topbar{min-height:38px}.lesson-head{padding:11px 0}.eyebrow{display:none}.scene-layout{min-height:290px}.viewer-shell{min-height:290px}.info-rail{max-height:340px}.teaching-toolbar{margin-top:10px;position:sticky;bottom:0;z-index:20}.teaching-toolbar button{min-height:51px;gap:2px}.workspace-note{display:none}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto}}
/* Classroom projection: keep the main teaching labels legible at tablet widths. */
.crystal-option .crystal-description{font-size:13px}.menu-heading,.topbar{font-size:13px}.version{font-size:12px;min-height:44px;cursor:pointer}.scene-caption{font-size:12px}.structure-badge{font-size:12px}.scene-footer{font-size:12px}.compact-button{font-size:12px}.legend-title{font-size:12px}.legend button{font-size:14px}.card p{font-size:14px}.card-kicker{font-size:12px}.atom-properties{font-size:14px}.atom-properties .coordinate-value{font-size:13px}.element-summary-row p{font-size:13px}.teaching-toolbar button{font-size:14px}.count-heading strong{font-size:16px}.count-heading span{font-size:12px}.site-filters button{font-size:13px}.count-result header{font-size:15px}.count-equation{font-size:17px}.count-equation small{font-size:12px}.count-total{font-size:14px}.count-note{font-size:12px}.source-details{font-size:12px}.source-details a,.source-details p{font-size:12px}.help-button{font-size:12px}.offline-status{font-size:11px}
@media(max-width:1150px){.card p{font-size:13px}.teaching-toolbar button{font-size:12px}.element-summary-row p{font-size:12px}.atom-properties{font-size:13px}}
@media(max-width:900px){.card p{font-size:12px}.structure-badge{font-size:11px}.teaching-toolbar button{font-size:11px}.crystal-option .crystal-description{font-size:12px}.scene-footer>span{font-size:11px}.source-details,.source-details a,.source-details p{font-size:11px}}
@media(max-width:700px) and (orientation:portrait){.teaching-toolbar button{font-size:11px}.crystal-option .crystal-description{font-size:11px}.structure-badge{font-size:10px}.topbar,.version{font-size:11px}.scene-footer{font-size:11px}.count-equation{font-size:15px}.count-heading span{font-size:11px}.site-filters button{font-size:12px}.count-total{font-size:13px}.card p{font-size:13px}.element-summary-row p{font-size:12px}}
.scene-layout{min-height:370px}.legend-bar{flex-shrink:0}.teaching-toolbar{position:sticky;bottom:0;z-index:20}
@media(min-width:701px){.is-counting .topbar{min-height:44px}.is-counting .lesson-head{padding:12px 0}.is-counting .scene-layout{min-height:320px}.is-counting .viewer-shell{min-height:255px}.is-counting .viewer{min-height:160px}}
.coordination-hud{position:absolute;left:50%;top:10px;transform:translateX(-50%);z-index:8;pointer-events:none;display:flex;flex-direction:column;align-items:center;gap:3px;min-width:250px;max-width:calc(100% - 30px);padding:9px 15px;border:1px solid #d6a447;background:#fffaf0ed;color:#5b421a;border-radius:9px;box-shadow:0 3px 12px #5740161a;text-align:center}.coordination-hud strong{font-size:14px}.coordination-hud span{font-size:11px;color:#775f39}.coordination-value{font-size:22px;color:#9b6818!important}.is-coordination .coordinate-note{opacity:.55}.is-coordination .viewer canvas{cursor:crosshair}.is-coordination .legend button:disabled{opacity:.65;text-decoration:none}
.info-rail .card{flex-shrink:0}
@media(max-width:900px){.coordination-hud{top:5px;padding:6px 10px;min-width:220px}.coordination-hud strong{font-size:12px}.coordination-hud span{font-size:10px}}
@media(max-width:700px) and (orientation:portrait){.sidebar{overflow:hidden}#crystal-menu{overflow-x:auto;overscroll-behavior-inline:contain;padding-bottom:5px}.crystal-option{flex:0 0 112px}}