:root{--navy:#071625;--navy2:#0c2236;--panel:#0a1d30;--paper:#f3f5f6;--white:#fff;--ink:#0a1a29;--muted:#687989;--line:#cbd4dc;--line-dark:#263d52;--orange:#ff5838;--cyan:#49b8e8;--green:#4bd3a4;--yellow:#f7c66a;--serif:Georgia,"Noto Serif SC","Songti SC",serif;--sans:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;--mono:"SFMono-Regular",Consolas,"Liberation Mono",Menlo,monospace}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--sans);font-size:16px;-webkit-font-smoothing:antialiased}button,input,select{font:inherit}button,a{-webkit-tap-highlight-color:transparent}a{color:inherit}button{cursor:pointer}
.site-header{height:78px;display:flex;align-items:center;justify-content:space-between;padding:0 clamp(20px,3.5vw,64px);border-bottom:1px solid var(--ink);background:rgba(243,245,246,.96);position:sticky;top:0;z-index:50;backdrop-filter:blur(12px)}.brand{display:flex;align-items:center;text-decoration:none;gap:18px}.brand-main{font-weight:900;letter-spacing:.11em;font-size:21px}.brand-divider{width:1px;height:28px;background:var(--line)}.brand-section{font-weight:700;font-size:15px}.head-actions{display:flex;align-items:center;gap:28px}.head-actions>a{text-decoration:none;font-size:14px}.head-actions>a:hover{color:var(--orange)}.language{display:flex;border:1px solid var(--ink)}.lang-btn{width:46px;height:34px;border:0;background:transparent;font:700 11px var(--mono);color:var(--muted)}.lang-btn.active{background:var(--ink);color:#fff}
.lesson-heading{padding:clamp(40px,6vw,88px) clamp(22px,5vw,86px);border-bottom:1px solid var(--ink)}.heading-meta{display:flex;justify-content:space-between;font:700 11px/1.4 var(--mono);letter-spacing:.14em;color:#1469a6;text-transform:uppercase}.heading-grid{display:grid;grid-template-columns:minmax(520px,1.1fr) minmax(320px,.9fr);gap:clamp(40px,7vw,130px);align-items:end;margin-top:36px}.heading-grid h1{font:500 clamp(52px,6.5vw,104px)/.99 var(--serif);letter-spacing:-.055em;margin:0}.heading-intro p{font-size:clamp(17px,1.35vw,22px);line-height:1.9;color:#526474;margin:0}.learning-goal{margin-top:28px;border-left:3px solid var(--orange);padding:3px 0 3px 18px;display:flex;gap:10px;flex-direction:column}.learning-goal strong{font:700 11px var(--mono);letter-spacing:.12em;color:var(--orange)}.learning-goal span{font-size:14px;line-height:1.7;color:var(--ink)}
.lab{display:grid;grid-template-columns:minmax(0,1.65fr) minmax(360px,.72fr);min-height:760px;background:var(--navy);color:#e9f4fc;border-bottom:1px solid #000}.viewport-panel{min-width:0;display:grid;grid-template-rows:auto 1fr auto;border-right:1px solid var(--line-dark)}.viewport-toolbar{height:62px;display:flex;align-items:center;justify-content:space-between;padding:0 24px;border-bottom:1px solid var(--line-dark)}.status{display:flex;align-items:center;gap:10px;font:700 11px var(--mono);letter-spacing:.08em;color:#aebdca}.live-dot{width:8px;height:8px;border-radius:50%;background:var(--green);box-shadow:0 0 12px rgba(75,211,164,.75)}.view-buttons{display:flex}.view-btn{background:transparent;border:0;border-left:1px solid var(--line-dark);color:#8fa4b6;padding:8px 13px;font-size:12px}.view-btn:first-child{border-left:0}.view-btn:hover,.view-btn.active{color:#fff}.view-btn.active{background:#142d42}.canvas-wrap{position:relative;min-height:610px;overflow:hidden;background:radial-gradient(circle at 50% 48%,#112d43 0,#081a2b 46%,#05111d 100%);touch-action:none}.canvas-wrap:before{content:"";position:absolute;inset:0;background-image:radial-gradient(circle,rgba(166,204,231,.36) 0 1px,transparent 1.2px);background-size:64px 64px;opacity:.13;pointer-events:none}.canvas-wrap canvas{position:absolute;inset:0;width:100%;height:100%;display:block}.canvas-key{position:absolute;left:24px;top:22px;display:flex;gap:18px;flex-wrap:wrap}.canvas-key span{display:flex;align-items:center;gap:7px;color:#8fa3b4;font:600 10px var(--mono);letter-spacing:.06em}.canvas-key i{width:18px;height:3px;background:var(--cyan)}.canvas-key .key-earth{height:8px;width:8px;border-radius:50%;background:#4b95be}.canvas-key .key-sat{height:8px;width:8px;border-radius:50%;background:var(--orange)}.drag-hint,.scale-note{position:absolute;right:22px;color:#71879a;font:600 10px var(--mono);letter-spacing:.05em}.drag-hint{top:22px}.scale-note{bottom:17px}.playbar{height:68px;display:flex;align-items:center;gap:20px;padding:0 24px;border-top:1px solid var(--line-dark);background:#081727}.play-btn{display:flex;align-items:center;gap:9px;background:var(--orange);border:0;color:#fff;padding:10px 16px;font-size:13px;font-weight:700}.play-icon{font-size:10px}.playbar label{display:flex;align-items:center;gap:8px;color:#91a4b5;font-size:11px}.playbar select{background:#0d2235;color:#fff;border:1px solid var(--line-dark);padding:6px 22px 6px 7px}.progress-track{height:2px;background:#263d52;flex:1}.progress-track span{display:block;background:var(--orange);width:5%;height:100%}.elapsed{font:700 12px var(--mono);min-width:75px;text-align:right;color:#d8e6f0}
.control-panel{background:#f8fafb;color:var(--ink);padding:28px clamp(20px,2.2vw,34px);overflow:auto;max-height:840px}.control-head{display:flex;align-items:start;justify-content:space-between;padding-bottom:20px;border-bottom:1px solid var(--line)}.panel-kicker{font:700 10px var(--mono);letter-spacing:.14em;color:#1570ad}.control-head h2{margin:7px 0 0;font:500 27px var(--serif)}.reset-btn{border:1px solid var(--line);background:#fff;color:var(--muted);padding:7px 11px;font-size:12px}.reset-btn:hover{border-color:var(--orange);color:var(--orange)}.presets{padding:20px 0;border-bottom:1px solid var(--line)}.presets>span{display:block;color:var(--muted);font-size:12px;margin-bottom:10px}.preset-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:7px}.preset-grid button{min-height:34px;border:1px solid var(--line);background:#fff;color:var(--ink);font-size:11px;padding:6px}.preset-grid button:hover,.preset-grid button.active{border-color:var(--orange);background:#fff3ef;color:#c9341b}.slider-row{padding:17px 0;border-bottom:1px solid #dbe2e7}.slider-row.active{background:linear-gradient(90deg,rgba(73,184,232,.08),transparent);margin:0 -10px;padding-left:10px;padding-right:10px}.slider-label{display:grid;grid-template-columns:32px 1fr auto;align-items:center;gap:9px;margin-bottom:11px}.symbol{font:500 23px var(--serif);color:#156da8}.slider-label strong{display:block;font-size:13px}.slider-label small{display:block;font-size:9px;line-height:1.35;color:#7a8995;margin-top:3px}.slider-label output{font:700 12px var(--mono);color:#263d52}input[type=range]{width:100%;height:4px;appearance:none;background:#d2dbe2;border-radius:0;outline:none}input[type=range]::-webkit-slider-thumb{appearance:none;width:15px;height:15px;border-radius:50%;background:var(--orange);border:3px solid #fff;box-shadow:0 0 0 1px var(--orange)}input[type=range]::-moz-range-thumb{width:11px;height:11px;border-radius:50%;background:var(--orange);border:2px solid #fff;box-shadow:0 0 0 1px var(--orange)}.j2-toggle{display:grid;grid-template-columns:42px 1fr;align-items:center;gap:12px;padding-top:20px;cursor:pointer}.j2-toggle input{position:absolute;opacity:0}.toggle-ui{width:40px;height:22px;border-radius:20px;background:#c8d2da;position:relative;transition:.2s}.toggle-ui:before{content:"";position:absolute;width:16px;height:16px;border-radius:50%;background:#fff;top:3px;left:3px;transition:.2s;box-shadow:0 1px 4px rgba(0,0,0,.25)}.j2-toggle input:checked+.toggle-ui{background:#1570ad}.j2-toggle input:checked+.toggle-ui:before{transform:translateX(18px)}.j2-toggle strong{display:block;font-size:12px}.j2-toggle small{display:block;color:var(--muted);font-size:10px;line-height:1.4;margin-top:4px}
.readouts{background:#fff;border-bottom:1px solid var(--ink);padding:clamp(50px,6vw,90px) clamp(22px,5vw,86px)}.section-label{display:grid;grid-template-columns:190px minmax(280px,.7fr) minmax(340px,1fr);align-items:end;gap:30px;margin-bottom:42px}.section-label>span,.learn-intro>span,.method-section>div:first-child>span,.source-section>div:first-child>span{font:700 11px var(--mono);letter-spacing:.15em;color:#1570ad}.section-label h2,.learn-intro h2,.method-section h2,.source-section h2{font:500 clamp(35px,4.5vw,65px)/1.06 var(--serif);letter-spacing:-.04em;margin:10px 0 0}.section-label p{margin:0;color:var(--muted);line-height:1.7}.metric-grid{display:grid;grid-template-columns:repeat(3,1fr);border-top:1px solid var(--ink);border-left:1px solid var(--ink)}.metric-grid article{min-height:175px;padding:24px;border-right:1px solid var(--ink);border-bottom:1px solid var(--ink);display:flex;flex-direction:column}.metric-grid article>span{font-size:13px;color:var(--muted)}.metric-grid strong{font:500 clamp(30px,3vw,52px)/1 var(--serif);margin:auto 0 7px}.metric-grid small{font:600 9px var(--mono);letter-spacing:.08em;color:#8a98a4}.vector-row{display:grid;grid-template-columns:1fr 1fr;border:1px solid var(--ink);border-top:0}.vector-row>div{padding:20px 24px}.vector-row>div+div{border-left:1px solid var(--ink)}.vector-row span{display:block;font:700 9px var(--mono);letter-spacing:.12em;color:#7a8996;margin-bottom:9px}.vector-row strong{font:600 clamp(12px,1.4vw,18px) var(--mono)}.warning{margin-top:18px;background:#fff0ec;border-left:4px solid var(--orange);padding:16px 20px;display:flex;gap:15px}.warning[hidden]{display:none}.warning strong{color:#c43620}.warning span{color:#6f514b}
.learn-section{padding:clamp(60px,8vw,120px) clamp(22px,5vw,86px);background:var(--paper);border-bottom:1px solid var(--ink)}.learn-intro{display:grid;grid-template-columns:190px .75fr 1fr;align-items:start;gap:30px;margin-bottom:50px}.learn-intro h2{margin-top:8px}.learn-intro p{color:var(--muted);font-size:17px;line-height:1.8;margin:6px 0 0}.concept-grid{display:grid;grid-template-columns:repeat(3,1fr);border-top:1px solid var(--ink);border-left:1px solid var(--ink)}.concept-grid article{min-height:290px;padding:28px;border-right:1px solid var(--ink);border-bottom:1px solid var(--ink);position:relative;background:rgba(255,255,255,.45)}.concept-symbol{position:absolute;right:22px;top:17px;font:500 54px var(--serif);color:#c8d4dc}.concept-grid h3{font:600 21px var(--serif);margin:42px 0 5px}.concept-grid small{font:600 9px/1.4 var(--mono);letter-spacing:.06em;color:#1570ad}.concept-grid p{font-size:14px;line-height:1.8;color:var(--muted);margin:28px 0 0}.method-section,.source-section{display:grid;grid-template-columns:minmax(290px,.7fr) minmax(430px,1.3fr);gap:clamp(40px,8vw,160px);padding:clamp(55px,7vw,105px) clamp(22px,5vw,86px);border-bottom:1px solid var(--ink)}.method-section{background:var(--navy);color:#e9f4fc}.method-copy p,.source-section p{font-size:17px;line-height:1.9;margin:0 0 24px;color:#9eb0bf}.method-copy dl{display:grid;grid-template-columns:1fr 1fr;margin-top:38px;border-top:1px solid var(--line-dark);border-left:1px solid var(--line-dark)}.method-copy dl div{padding:18px;border-right:1px solid var(--line-dark);border-bottom:1px solid var(--line-dark)}.method-copy dt{font:700 11px var(--mono);color:var(--cyan);margin-bottom:8px}.method-copy dd{font:600 13px var(--mono);margin:0}.source-section{background:#fff}.source-section p{color:var(--muted)}.source-section a{display:inline-block;text-decoration:none;border-bottom:1px solid var(--ink);padding-bottom:4px;font-weight:700}.source-section a:hover{color:var(--orange);border-color:var(--orange)}
.site-footer{min-height:90px;display:flex;align-items:center;justify-content:space-between;padding:20px clamp(22px,5vw,86px);background:#fff;color:var(--muted);font-size:12px}.site-footer a{text-decoration:none;font-weight:900;letter-spacing:.1em;color:var(--ink)}
@media(max-width:1100px){.heading-grid{grid-template-columns:1fr}.lab{grid-template-columns:1fr}.viewport-panel{border-right:0}.control-panel{max-height:none}.section-label,.learn-intro{grid-template-columns:150px 1fr}.section-label p,.learn-intro p{grid-column:2}.metric-grid,.concept-grid{grid-template-columns:repeat(2,1fr)}.method-section,.source-section{grid-template-columns:1fr;gap:35px}.canvas-wrap{min-height:560px}}
@media(max-width:700px){body{font-size:15px}.site-header{height:64px;padding:0 16px}.brand{gap:10px}.brand-main{font-size:16px}.brand-divider{height:22px}.brand-section{font-size:13px}.head-actions{gap:10px}.head-actions>a{display:none}.lang-btn{width:40px;height:31px}.lesson-heading{padding:40px 20px}.heading-meta span:last-child{display:none}.heading-grid{margin-top:25px}.heading-grid h1{font-size:clamp(45px,14vw,70px)}.heading-intro p{font-size:16px}.lab{min-height:0}.viewport-toolbar{height:auto;padding:12px 14px;align-items:flex-start;gap:12px}.status{padding-top:8px;font-size:9px}.view-buttons{display:grid;grid-template-columns:1fr 1fr}.view-btn{padding:7px 10px;border:1px solid var(--line-dark);margin:-1px 0 0 -1px}.canvas-wrap{min-height:430px}.canvas-key{left:14px;top:14px;gap:10px}.canvas-key span{font-size:8px}.drag-hint{display:none}.scale-note{left:14px;right:auto;font-size:8px}.playbar{padding:0 14px;gap:10px}.playbar label>span{display:none}.play-btn{padding:9px 12px}.elapsed{min-width:64px}.control-panel{padding:24px 18px}.preset-grid{grid-template-columns:repeat(3,1fr)}.readouts,.learn-section,.method-section,.source-section{padding:48px 20px}.section-label,.learn-intro{display:block}.section-label>span,.learn-intro>span{display:block;margin-bottom:15px}.section-label p,.learn-intro p{margin-top:20px}.metric-grid,.concept-grid{grid-template-columns:1fr}.metric-grid article{min-height:132px}.concept-grid article{min-height:230px}.vector-row{grid-template-columns:1fr}.vector-row>div+div{border-left:0;border-top:1px solid var(--ink)}.method-copy dl{grid-template-columns:1fr}.site-footer{align-items:flex-start;flex-direction:column;gap:9px;padding:26px 20px}.site-footer span:nth-child(2){line-height:1.5}.warning{flex-direction:column;gap:5px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important}}
.heading-grid h1{white-space:pre-line}