/* Albert Official · shared palette and page frame */
:root {color-scheme:light;--page:#f0f3f7;--surface:#fff;--surface-alt:#eaf0f6;--ink:#233247;--muted:#596b81;--subtle:#62738a;--line:#dce3eb;--line-strong:#bccbd9;--blue:#386bc4;--accent:#386bc4;--accent-contrast:#fff;--accent-soft:#e7effc;--mint:#dceee8;--teal:#217c78;--green:#337c63;--copper:#ac7238;--red:#b34e52;--topbar:#f0f3f7;--shadow:0 5px 18px #22344f05;--sans:"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;--serif:Georgia,"Songti SC",serif;--mono:Consolas,"SFMono-Regular",monospace;--art-ink:#426d97;--art-secondary:#629489;--art-accent:#c28a54;--art-faint:#b3c8d8;--art-paper:#e8f0f7;font-family:var(--sans)}
:root[data-theme=dark] {color-scheme:dark;--page:#142133;--surface:#1d2d42;--surface-alt:#25374e;--ink:#e4ebf3;--muted:#afbed0;--subtle:#a3b2c4;--line:#354559;--line-strong:#51677e;--blue:#9bbfff;--accent:#9bbfff;--accent-contrast:#142133;--accent-soft:#283e5b;--mint:#294b44;--teal:#87c9c0;--green:#96cba9;--copper:#e0b084;--red:#f09194;--topbar:#142133;--shadow:none;--art-ink:#9cbfe0;--art-secondary:#8ebeb0;--art-accent:#e0b084;--art-faint:#4a657b;--art-paper:#263c52}
*{box-sizing:border-box}html{font-size:16px;scroll-padding-top:100px}body{margin:0;background:var(--page);color:var(--ink);font-family:var(--sans);line-height:1.7}a{color:inherit}button,input,select{font:inherit}button,a,input,select{-webkit-tap-highlight-color:transparent}a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible{outline:3px solid var(--blue);outline-offset:4px}button{cursor:pointer}
.ao-header{position:relative;z-index:20;display:flex;align-items:center;gap:30px;width:min(1200px,calc(100% - 80px));min-height:84px;margin:auto;font-size:14px;line-height:1.5}
.ao-brand{display:flex;align-items:center;gap:11px;text-decoration:none;white-space:nowrap;font-size:19px;font-weight:650;letter-spacing:-.4px}.ao-mark{display:grid;place-items:center;width:31px;height:31px;border-radius:9px;background:#2e557d;color:white;font:23px Georgia,serif}.ao-header nav{display:flex;gap:25px;margin-left:auto}.ao-header nav a{color:var(--muted);text-decoration:none}.ao-header nav a:hover{color:var(--blue)}.ao-theme{display:flex;gap:2px;border:1px solid var(--line);border-radius:24px;padding:3px;background:var(--surface)}.ao-theme button{border:0;background:none;color:var(--muted);padding:6px 12px;border-radius:20px;font-size:12px}.ao-theme button[aria-pressed=true]{background:var(--accent-soft);color:var(--ink)}
.site-shell{width:min(1200px,calc(100% - 80px));margin-inline:auto}.tool-hero,.simulator-page .tool-hero{display:grid;grid-template-columns:minmax(0,1fr) 260px;align-items:center;gap:30px;padding:26px 32px;margin-top:8px;border:1px solid var(--line);border-radius:16px;background:var(--surface);min-height:194px}.tool-intro{min-width:0}.tool-hero .eyebrow{font-size:11px;letter-spacing:.12em;margin-bottom:8px;color:var(--muted)}.tool-hero h1{font-family:var(--sans);font-size:32px;letter-spacing:-.7px;margin:0 0 10px;line-height:1.35}.tool-hero .title-en{display:none}.tool-hero .lead{font-size:14px;line-height:1.9;margin:0;max-width:760px;color:var(--muted)}.tool-art{background:var(--surface-alt);border-radius:12px;padding:14px;display:grid;place-items:center;min-height:150px}.tool-art svg{width:100%;height:140px}.tool-layout{gap:22px;margin-top:24px;margin-bottom:60px;grid-template-columns:minmax(280px,330px) minmax(0,1fr)}.tool-layout.wide-controls{grid-template-columns:minmax(310px,360px) minmax(0,1fr)}.tool-layout>aside.panel{top:20px}.panel{border:1px solid var(--line);border-radius:14px;background:var(--surface);box-shadow:var(--shadow)}.panel-header{padding:17px 20px;min-height:62px}.panel-header h2,.panel-header h3{font-size:17px}.panel-body{padding:22px 20px}.label-line{font-size:14px}.value-pill{border-radius:7px;font-size:13px}.button,.button-ghost,.button-primary{border-radius:8px;min-height:38px}.metric{padding:17px 20px}.metric-value{font-size:26px;font-variant-numeric:tabular-nums}.metric-label{font-size:12px;color:var(--muted)}.metric-label .heading-en{display:none}.legend{font-size:12px;gap:10px 18px;line-height:1.65;flex-wrap:wrap}.canvas-wrap{padding:18px 18px 20px}.canvas-wrap canvas{display:block;width:100%}.subchart-head h3{font-size:14px}.adrc-page .adrc-chart-stack{grid-template-columns:1fr}.adrc-page .adrc-chart-stack>.subchart:nth-child(3){border-left:0}.adrc-page .subchart{padding:18px}.subchart-head{flex-wrap:wrap}.math-section{padding-bottom:65px}.section-head h2{font-size:25px}.math-card{border:1px solid var(--line);border-radius:14px;background:var(--surface);padding:25px;margin-bottom:18px}.math-card h3{font-family:var(--sans);font-size:19px}.math-card p,.math-card li{font-size:15px;line-height:1.9}.math-block{background:var(--surface-alt);border:1px solid var(--line);border-radius:8px;padding:20px 16px;overflow-x:auto;overflow-y:hidden;max-width:100%;font-size:16px}.katex-display{margin:0;overflow:visible}.math-block .katex-display>.katex{white-space:nowrap;text-align:left}.learning-grid{gap:18px}.note-card{border:1px solid var(--line);border-radius:12px;background:var(--surface-alt);padding:20px}.note-card h4{font-size:15px}.note-card p{font-size:14px}.formula-scroll-note{font-size:12px;color:var(--muted)}.result-tile{min-height:110px;padding:15px 16px}.result-tile strong{font-size:21px}.result-tile span,.result-tile small{font-size:11px}.footer{font-size:12px;line-height:1.8;margin-top:0;padding-bottom:30px}
.line-illustration{fill:none;stroke:var(--art-ink);stroke-width:1.65;stroke-linecap:round;stroke-linejoin:round}.line-illustration :is(path,circle,ellipse,rect){vector-effect:non-scaling-stroke}.line-illustration .construction{stroke:var(--art-faint);stroke-width:1;fill:none}.line-illustration .detail{stroke-width:1.05}.line-illustration .curve{stroke-width:2.35}.line-illustration .accent{stroke:var(--art-accent)}.line-illustration .secondary{stroke:var(--art-secondary)}.line-illustration .paper{fill:var(--art-paper)}.line-illustration .under-stroke{stroke:var(--art-paper);stroke-width:7}.line-illustration .figure-text{fill:var(--art-ink);stroke:none;font:10px var(--sans)}
@media(max-width:1000px){.ao-header,.site-shell{width:calc(100% - 48px)}.tool-hero,.simulator-page .tool-hero{grid-template-columns:1fr 200px;padding:24px}.tool-hero h1{font-size:29px}.tool-layout,.tool-layout.wide-controls{grid-template-columns:290px minmax(0,1fr)}}
@media(max-width:800px){.ao-header,.site-shell{width:calc(100% - 36px)}.ao-header{flex-wrap:wrap;gap:12px 16px;padding:18px 0;min-height:80px}.ao-brand{font-size:17px}.ao-header nav{order:3;width:100%;margin:0;padding-left:40px;gap:24px;font-size:12px}.ao-theme{margin-left:auto}.ao-theme button{padding:5px 9px}.tool-hero,.simulator-page .tool-hero{grid-template-columns:1fr 125px;gap:15px;padding:22px}.tool-art{padding:8px;min-height:115px}.tool-art svg{height:100px}.tool-hero h1{font-size:26px}.tool-layout,.tool-layout.wide-controls{grid-template-columns:1fr}.tool-layout>aside.panel{position:static}.learning-grid{grid-template-columns:1fr}.metric-value{font-size:24px}}
@media(max-width:500px){.tool-hero,.simulator-page .tool-hero{grid-template-columns:1fr;padding:22px;gap:17px}.tool-art{min-height:100px}.tool-art svg{height:110px}.tool-hero h1{font-size:26px}.tool-hero .lead{font-size:13px}.tool-hero .eyebrow{font-size:10px}.tool-layout{margin-top:18px}.panel-body{padding:20px 18px}.canvas-wrap{padding:16px 8px}.adrc-page .subchart{padding:16px 8px}.metrics{grid-template-columns:repeat(2,minmax(0,1fr))}.metric{padding:15px 18px}.math-card{padding:20px 17px}.math-block{padding:18px 14px;font-size:15px}.math-card h3{font-size:18px}.math-card p,.math-card li{font-size:14px}.results-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.heading-en{display:none}.field-row{grid-template-columns:minmax(0,1fr) minmax(85px,110px)}.formula-scroll-note{font-size:11px}}
.tool-hero,.tool-layout,.math-section{width:min(1200px,calc(100% - 80px))}main.site-shell>:where(.tool-hero,.tool-layout,.math-section){width:100%}
@media(max-width:1000px){.tool-hero,.tool-layout,.math-section{width:calc(100% - 48px)}}
@media(max-width:800px){.tool-hero,.tool-layout,.math-section{width:calc(100% - 36px)}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*::before,*::after{animation:none!important;transition:none!important}}
.math-section>.section-head{display:block;margin-bottom:25px;padding-bottom:22px}
.math-section>.section-head h2{font-size:25px;line-height:1.5;letter-spacing:-.4px;margin:0 0 10px}
.math-section>.section-head h2 .heading-en{display:none}
.math-section>.section-head>p{max-width:850px;font-size:14px;line-height:1.9;margin:0}
.learning-note{border-radius:10px;background:var(--surface-alt);border:1px solid var(--line);padding:20px}
.math-block:focus-visible{outline:2px solid var(--blue);outline-offset:3px}
html{scroll-behavior:auto}
@media(max-width:500px){.subchart-head .inline-en{display:none}.field-row{grid-template-columns:minmax(0,1fr) 90px 32px;column-gap:7px}.field-row .unit{font-size:10px}.field-row label{font-size:13px}}
.math-block .katex{position:relative}.math-card .formula-scroll-note,.reading-page .formula-scroll-note{font-size:11px;line-height:1.5;color:var(--muted);margin-top:-8px;margin-bottom:18px}