:root{color-scheme:dark;--bg:#070d18;--panel:#0b1421;--line:#223043;--ink:#eaf1f6;--muted:#9aabbf;--cyan:#65d8ed;--gold:#efbd76;--serif:Georgia,"Times New Roman",serif}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);color:var(--ink);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;line-height:1.6}button,input{font:inherit}button,a,input{ -webkit-tap-highlight-color:transparent}button{cursor:pointer}button:focus-visible,a:focus-visible,input:focus-visible,canvas:focus-visible,summary:focus-visible{outline:2px solid var(--cyan);outline-offset:4px}a{color:inherit}button{color:var(--ink);border:1px solid var(--line);background:#111f30;border-radius:7px;min-height:40px;transition:background .15s,border-color .15s}button:hover{background:#1c3044;border-color:#4b6882}button:active{background:#254257}.page{max-width:1512px;margin:auto;padding:0 5vw}.masthead{height:96px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);gap:20px}.wordmark{text-decoration:none;font-size:13px;font-weight:700;letter-spacing:2px;display:flex;align-items:center;gap:12px}.logo{font-size:30px;font-weight:400;color:var(--gold)}.edition{font-size:10px;letter-spacing:1.8px;color:var(--muted);display:flex;align-items:center;gap:12px}.status-dot{height:5px;width:5px;border-radius:50%;background:var(--cyan)}.intro{position:relative;padding:57px 0 43px;display:grid;grid-template-columns:1.05fr 1fr;align-items:end;column-gap:10%}.intro .eyebrow{grid-column:1/-1;margin-bottom:17px}.eyebrow{font-size:10px;line-height:1.4;letter-spacing:2px;font-weight:650;color:var(--cyan);margin:0 0 12px}h1{font:400 clamp(39px,4.5vw,67px)/1.08 var(--serif);letter-spacing:-2px;margin:0}em{font-weight:400;color:var(--gold)}.lede{font-size:15px;color:var(--muted);max-width:480px;margin:0 0 3px;line-height:1.8}.explorer{display:grid;grid-template-columns:minmax(0,1fr) 342px;border:1px solid var(--line);border-radius:14px;overflow:hidden;background:var(--panel);box-shadow:0 20px 60px #0003}.visual-panel{min-width:0;background:radial-gradient(ellipse at 50% 40%,#15283a 0,#0b1524 56%,#09121f 100%);display:flex;flex-direction:column}.scene-header{display:flex;align-items:center;justify-content:space-between;padding:20px 25px;border-bottom:1px solid #22304399;gap:12px}.view-tabs{display:flex;gap:3px;background:#07101c;padding:4px;border:1px solid var(--line);border-radius:9px}.view-tabs button{min-height:36px;font-size:12px;background:transparent;border-color:transparent;padding:0 14px;color:var(--muted)}.view-tabs button.active{background:#1b3042;color:var(--ink);border-color:#334d61}.scene-tag{font-size:9px;letter-spacing:1.6px;color:var(--muted);white-space:nowrap}.viewport{min-height:535px;flex:1;position:relative;isolation:isolate;overflow:hidden}.viewport canvas{display:block;width:100%;height:100%;position:absolute;inset:0;cursor:grab;touch-action:none}.viewport canvas:active{cursor:grabbing}.scene-heading{position:absolute;left:27px;top:24px;pointer-events:none}.scene-heading>span,.dimension-tag{font-size:9px;letter-spacing:1.7px;color:#a9bfcd}.scene-heading h2{font:400 clamp(19px,1.9vw,27px)/1.4 var(--serif);margin:7px 0;color:#d8e5ef}.dimension-tag{position:absolute;right:25px;top:33px;font-size:8px;max-width:125px;text-align:right;line-height:1.7}.legend{position:absolute;left:27px;bottom:80px;display:flex;gap:22px;font-size:10px;color:#abc2d1;pointer-events:none}.legend>span{display:flex;align-items:center;gap:7px}.legend i{display:block;width:12px;height:2px}.cyan{background:var(--cyan)}.gold{background:var(--gold)}.scene-bottom{position:absolute;left:25px;right:25px;bottom:20px;display:flex;align-items:center;justify-content:space-between;gap:12px}.gesture-hint{font-size:10px;color:#a2b6c7}.camera-buttons{display:flex;gap:5px}.camera-buttons button{font-size:17px;min-width:36px;min-height:36px;background:#0b1825df}.camera-buttons button:last-child{font-size:11px;padding:0 11px}.scene-note{padding:17px 25px;font-size:11px;line-height:1.8;color:#a2b5c5;border-top:1px solid #22304399;min-height:72px;background:#091320b3}.control-panel{padding:25px 24px;border-left:1px solid var(--line);background:#0e1826}.panel-top{display:flex;align-items:center;justify-content:space-between;margin-bottom:21px;gap:8px}.panel-top .eyebrow{font-size:9px;margin:0}.reset{border:0;background:transparent;min-height:30px;font-size:11px;color:var(--muted);padding:0 6px}.control-label{font-size:12px;display:flex;justify-content:space-between}.control-label>span{font-family:var(--serif);font-style:italic;color:var(--gold)}.mass-entry{display:flex;align-items:baseline;gap:12px;margin-top:8px}.mass-entry input{width:185px;max-width:80%;border:0;border-bottom:1px solid #33475e;border-radius:0;padding:1px 0;background:none;color:var(--ink);font-size:43px;letter-spacing:-1.5px;font-weight:300;line-height:1.2}.mass-entry>span{font-size:19px;color:var(--gold);font-family:var(--serif)}.muted{color:var(--muted);font-size:11px}.mass-range{width:100%;height:25px;margin:9px 0 0;accent-color:var(--cyan);cursor:pointer}.range-ends{display:flex;justify-content:space-between;color:var(--muted);font-size:10px}.presets{display:flex;gap:8px;margin:17px 0 22px}.presets button{flex:1;min-height:34px;font-size:11px;color:var(--muted)}.presets .selected{border-color:#437c88;background:#163341;color:var(--cyan)}.scale-field{border:0;margin:0;padding:0}.scale-field legend{font-size:12px;margin-bottom:10px}.scale-options{display:flex;flex-direction:column;gap:6px}.scale-options label{font-size:11px;display:flex;align-items:center;gap:8px;cursor:pointer;min-height:24px}.scale-options input{accent-color:var(--cyan);margin:0;width:14px;height:14px}.scale-explainer{font-size:10px;line-height:1.7;color:var(--muted);margin:8px 0 19px;min-height:34px}.readouts{border-top:1px solid var(--line)}.readout{display:flex;align-items:center;justify-content:space-between;gap:10px;padding:15px 0;border-bottom:1px solid var(--line)}.readout>span{font-size:10px;line-height:1.5}.readout>span small{display:block;color:var(--muted);font-size:9px;margin-top:3px}.readout strong{font-weight:450;font-size:19px;letter-spacing:-.6px;white-space:nowrap}.readout strong small{font-size:10px;letter-spacing:0;color:var(--muted)}.bound-card{border:1px solid #6c563552;background:linear-gradient(130deg,#30251766,#17233088);border-radius:8px;padding:18px;margin-top:22px}.bound-card .eyebrow{color:var(--gold);font-size:9px;letter-spacing:1.5px}.bound-formula{font:400 18px/1.4 var(--serif);white-space:nowrap;color:#e8d4b7;display:flex;align-items:center;gap:4px}.fraction{display:inline-flex;flex-direction:column;font-size:14px;text-align:center;line-height:1.2;margin:0 4px}.fraction span:first-child{border-bottom:1px solid #ad997a;padding:0 3px 2px}.fraction span:last-child{padding-top:2px}.radicand{border-top:1px solid #b19d80;padding:1px 3px}.bound-value{font-size:32px;font-weight:300;margin:11px 0 6px;line-height:1.2;letter-spacing:-.7px}.bound-value>span{font:400 16px var(--serif);color:var(--gold);letter-spacing:0}.equality{font-size:10px;margin:0;color:#e3bc85}.equality>span{border:1px solid #907142;border-radius:50%;display:inline-flex;align-items:center;justify-content:center;width:16px;height:16px;margin-right:3px}.bound-note{font-size:9px;line-height:1.8;color:#b4aa9c;margin:10px 0 0}
.example-check{margin-top:28px;border:1px solid var(--line);border-radius:12px;padding:25px 28px;display:grid;grid-template-columns:250px 1fr;gap:24px;background:#0c1623}.example-check h2{font:400 25px/1.25 var(--serif);margin:8px 0}.example-check .check-type{font-size:10px;color:var(--gold);display:inline-block;border:1px solid #735c3977;padding:3px 8px;border-radius:4px;margin-top:3px}.equation-steps{display:grid;grid-template-columns:1fr 1fr;gap:13px 24px}.equation-step p{margin:0;font-size:11px;color:var(--muted)}.equation-step code{display:block;color:#d6e5ef;font:12px/1.8 ui-monospace,SFMono-Regular,Consolas,monospace;margin-top:6px;overflow-wrap:anywhere}.example-context{grid-column:1/-1;border-top:1px solid var(--line);padding-top:15px;margin:0;font-size:11px;color:var(--muted)}.example-context a{color:var(--cyan);text-underline-offset:3px}.explanation{padding:67px 0 38px}.explanation-heading{display:flex;justify-content:space-between;align-items:start}.explanation-heading h2{font:400 36px/1.2 var(--serif);margin:0;text-align:right}.explanation-grid{margin-top:39px;display:grid;grid-template-columns:repeat(3,1fr);gap:33px}.explanation-grid article{border-top:1px solid var(--line);padding-top:21px}.article-number{font-size:9px;letter-spacing:1.8px;color:var(--cyan)}h3{font-weight:500;font-size:16px;line-height:1.5;margin:13px 0}.explanation-grid p{font-size:12px;line-height:1.85;color:#b4c3d1}.explanation-grid p.muted{color:var(--muted);font-size:11px}.math-block{font:15px/2 var(--serif);color:#e4c997;border-left:2px solid #705b3f;padding-left:15px;margin:20px 0}.scope-note{display:flex;gap:17px;padding:24px 26px;background:#0d1724;border:1px solid var(--line);border-radius:9px;align-items:start}.scope-icon{flex-shrink:0;border:1px solid #567386;color:#a5c5d7;border-radius:50%;width:22px;height:22px;display:flex;align-items:center;justify-content:center;font-family:var(--serif);margin-top:3px}.scope-note h3{margin:0 0 6px;font-size:13px}.scope-note p{margin:0;font-size:11px;color:var(--muted);line-height:1.9}footer{display:flex;justify-content:space-between;gap:30px;padding:36px 0 32px;border-top:1px solid var(--line);margin-top:45px}.source-links{display:flex;flex-wrap:wrap;gap:10px 22px}.source-links a{font-size:10px;text-decoration:none;color:#aebed0}.source-links a:hover{color:var(--cyan);text-decoration:underline}.source-links a span{color:var(--cyan);margin-left:3px}.footer-note{font-size:9px;line-height:1.8;color:var(--muted);margin:0;text-align:right}.error{color:#f7bc9f;font-size:11px}.error[hidden]{display:none}sub{font-size:.7em}button:disabled{opacity:.45;cursor:default}
@media(min-width:1450px){.viewport{min-height:640px}}
@media(max-width:1080px){.page{padding:0 4vw}.explorer{grid-template-columns:minmax(0,1fr) 310px}.control-panel{padding:22px 20px}.scene-tag{display:none}.dimension-tag{display:none}.scene-bottom{flex-direction:column;align-items:start}.legend{bottom:112px}.scene-note{font-size:10px}.equation-steps{grid-template-columns:1fr}.example-check{grid-template-columns:210px 1fr}}
@media(max-width:780px){.masthead{height:77px}.edition{display:none}.intro{padding:37px 0 31px;grid-template-columns:1fr;gap:18px}.intro .eyebrow{margin:0}.lede{max-width:560px;font-size:13px}.intro h1{font-size:48px}.explorer{grid-template-columns:1fr}.viewport{min-height:450px}.scene-bottom{flex-direction:row;align-items:center}.legend{bottom:78px}.control-panel{border-left:0;border-top:1px solid var(--line);padding:25px;display:grid;grid-template-columns:1fr 1fr;gap:0 25px}.panel-top{grid-column:1/-1}.control-label,.mass-entry,.control-panel>.muted,.mass-range,.range-ends,.presets,.scale-field,.scale-explainer,.error{grid-column:1}.readouts{grid-column:2;grid-row:2/8;align-self:start}.bound-card{grid-column:2;grid-row:8/12;margin:0;align-self:start}.scale-explainer{margin-bottom:0}.readout{flex-direction:column;align-items:start;gap:6px}.example-check{grid-template-columns:1fr;gap:18px}.equation-steps{grid-template-columns:1fr 1fr}.explanation-heading h2{font-size:30px}.explanation-grid{gap:24px;grid-template-columns:1fr}.explanation-grid article{display:grid;grid-template-columns:1fr 1fr;gap:0 25px}.article-number,.explanation-grid h3{grid-column:1/-1}.explanation-grid p{margin-top:5px}.explanation-grid p.muted{grid-column:1/-1}.math-block{margin:6px 0 15px}.source-links{flex-direction:column}}
@media(max-width:600px){.page{padding:0 16px}.wordmark{font-size:11px;letter-spacing:1.6px}.masthead{height:70px}.intro h1{font-size:42px;letter-spacing:-1.4px}.intro{gap:17px}.viewport{min-height:395px}.scene-header{padding:13px 15px}.view-tabs button{padding:0 11px;font-size:11px}.scene-heading{left:19px;top:20px}.scene-heading>span{font-size:8px}.scene-heading h2{font-size:21px}.scene-bottom{left:16px;right:16px;bottom:15px;align-items:start;flex-direction:column;gap:10px}.gesture-hint{font-size:9px}.camera-buttons{align-self:flex-end}.camera-buttons button{min-width:40px;min-height:40px}.legend{left:19px;bottom:110px;font-size:9px;gap:13px}.scene-note{padding:14px 18px}.control-panel{padding:24px 20px;display:block}.mass-entry input{width:180px}.scale-options{flex-direction:row;gap:15px;flex-wrap:wrap}.scale-explainer{margin-bottom:21px}.readout{flex-direction:row;align-items:center}.readout strong{font-size:23px}.readout>span{font-size:11px}.readout>span small{font-size:10px}.bound-card{margin-top:20px;padding:20px}.bound-formula{font-size:22px}.bound-note{font-size:10px}.equality{font-size:11px}.example-check{padding:22px 20px;margin-top:19px}.equation-steps{grid-template-columns:1fr;gap:18px}.example-check h2{font-size:27px}.explanation{padding-top:40px}.explanation-heading{flex-direction:column;gap:10px}.explanation-heading h2{text-align:left;font-size:31px}.explanation-grid{margin-top:26px}.explanation-grid article{display:block}.explanation-grid p{font-size:12px}.math-block{margin:17px 0}.scope-note{padding:19px 17px;gap:12px}.scope-note p{font-size:10px}footer{flex-direction:column;margin-top:30px;padding-top:27px}.footer-note{text-align:left}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}button{transition:none}}