/* 灵驭物理 v6.3 — one page, one visual language. */
:root {
  --blue:#2458f5; --blue-dark:#1946d4; --ink:#192b48; --muted:#63728a;
  --paper:#f6f8fd; --line:#e2e8f2; --warm:#ffad66; --soft-blue:#edf3ff;
  --soft-warm:#fff5e9; --header-height:80px; --display-font:"DengXian","Microsoft YaHei","PingFang SC",sans-serif;
  font-family:"Microsoft YaHei","PingFang SC",sans-serif; color:var(--ink); background:#fff; font-synthesis:none;
}
* { box-sizing:border-box; }
html { scroll-behavior:smooth; scroll-padding-top:calc(var(--header-height) + 24px); }
body,figure,h1,h2,h3,h4,h5,p { margin:0; }
body { min-width:min(320px,100%); }
p,h1,h2,h3,h4,h5 { text-wrap:pretty; }
a { color:inherit; text-decoration:none; }
button,a,summary { -webkit-tap-highlight-color:transparent; touch-action:manipulation; }
button { font:inherit; color:inherit; border:0; cursor:pointer; }
button:disabled { cursor:default; opacity:.35; }
img { display:block; width:100%; height:auto; }
em { font-style:normal; }
[hidden] { display:none!important; }
a:focus-visible,button:focus-visible,summary:focus-visible { outline:3px solid #b96c29; outline-offset:4px; }
.sr-only { position:absolute; width:1px; height:1px; padding:0; margin:-1px; overflow:hidden; clip-path:inset(50%); white-space:nowrap; border:0; }
.skip-link { position:fixed; z-index:100; left:16px; top:-80px; padding:16px 20px; color:#fff; background:var(--ink); }
.skip-link:focus { top:12px; }
.section-wrap { width:calc(100% - 96px); max-width:1200px; margin-inline:auto; }
.site-header { position:sticky; z-index:30; top:0; background:#fffffff0; backdrop-filter:blur(18px); border-bottom:1px solid #192b480c; }
.header-inner { max-width:1520px; margin:auto; min-height:80px; padding:14px 32px; display:flex; align-items:center; gap:26px; }
.wordmark { display:flex; align-items:center; gap:9px; white-space:nowrap; }
.brand-symbol { width:36px; height:36px; flex:none; }
.brand-type strong { display:block; font-size:23px; letter-spacing:.01em; line-height:1.15; }
.brand-type small { display:block; color:var(--muted); font-size:9px; letter-spacing:.08em; margin-top:5px; }
.content-nav,.quick-nav { display:flex; align-items:center; white-space:nowrap; }
.content-nav { gap:24px; font-size:13px; margin-left:auto; }
.content-nav a { display:inline-flex; align-items:center; min-height:44px; }
.content-nav a:hover,.quick-link:hover,.account-entry:hover { color:var(--blue); }
.quick-nav { gap:20px; }
.quick-link { display:flex; align-items:center; gap:7px; min-height:44px; padding:10px 0; background:transparent; color:var(--muted); font-size:12px; }
.quick-link>span:last-child { font-size:16px; }
.nav-category { position:relative; }
.category-trigger { color:var(--ink); font-size:13px; }
.category-trigger .nav-chevron { display:inline-flex; align-items:center; justify-content:center; width:14px; height:14px; flex:none; }
.nav-chevron svg { display:block; width:14px; height:14px; }
.category-trigger[aria-expanded="true"] { color:var(--blue); }
.category-trigger[aria-expanded="true"] .nav-chevron { transform:rotate(180deg); }
.category-panel { position:absolute; z-index:40; top:100%; right:0; width:290px; max-height:calc(100svh - var(--header-height) - 20px); overflow-y:auto; overscroll-behavior:contain; padding:8px; background:#fff; border:1px solid var(--line); border-radius:12px; box-shadow:0 16px 40px #192b4820; white-space:normal; }
.category-panel a { display:flex; justify-content:space-between; align-items:center; gap:16px; min-height:64px; padding:11px 14px; border-radius:7px; }
.category-panel a:hover,.category-panel a:focus-visible { color:var(--blue-dark); background:var(--soft-blue); }
.category-panel a>span:first-child { display:grid; gap:6px; }
.category-panel strong { font-size:14px; font-weight:500; line-height:1.5; }
.category-panel small { color:var(--muted); font-size:11px; line-height:1.6; }
.category-panel a>span:last-child { color:var(--blue); font-size:16px; }
.ai-link { color:var(--blue); }
.account-entry { display:inline-flex; align-items:center; gap:12px; min-height:44px; padding-left:24px; border-left:1px solid var(--line); font-size:13px; white-space:nowrap; }
.primary-action,.secondary-action { display:inline-flex; align-items:center; justify-content:space-between; gap:26px; min-height:52px; padding:14px 23px; border:1px solid transparent; border-radius:8px; font-size:15px; }
.primary-action { background:var(--blue); color:#fff; box-shadow:0 5px 12px #2458f51a; }
.primary-action:hover { background:var(--blue-dark); }
.secondary-action { background:#fff; border-color:#cad6ef; }
.secondary-action:hover { border-color:var(--blue); color:var(--blue); }
.primary-action>span,.secondary-action>span { font-size:22px; line-height:1; }
.plain-link,.quiet-link { display:inline-flex; align-items:center; gap:12px; min-height:44px; padding:8px 0; background:transparent; font-size:14px; }
.plain-link { color:var(--blue-dark); }
.quiet-link { color:var(--muted); font-size:13px; }
.plain-link:hover,.quiet-link:hover { color:var(--blue); text-decoration:underline; text-underline-offset:5px; }
.eyebrow { color:var(--blue-dark); font-size:13px; font-weight:500; letter-spacing:.04em; }
h2,h3 { font-family:var(--display-font); }
h2 { font-size:clamp(34px,3.5vw,48px); letter-spacing:-.045em; font-weight:700; line-height:1.45; }
.section-heading { margin-bottom:52px; }
.section-heading .eyebrow { margin-bottom:19px; }
.phone-break { display:none; }

/* The hero has three text roles: category, promise, concrete use. */
.launch-hero { padding:38px 24px 0; overflow:clip; background:radial-gradient(ellipse at 73% 76%,#eaf1ff 0%,transparent 55%),radial-gradient(ellipse at 16% 78%,#fff4e8 0%,transparent 37%),linear-gradient(#fff 10%,#f9fbff 85%,#fff); text-align:center; }
.launch-copy { position:relative; z-index:2; }
.launch-eyebrow { display:flex; align-items:center; justify-content:center; gap:10px; color:var(--muted); font-size:13px; letter-spacing:.05em; }
.launch-eyebrow>span { width:6px; height:6px; background:var(--warm); border-radius:50%; box-shadow:0 0 0 5px #ffad6618; }
.launch-copy h1 { font-family:var(--display-font); font-size:clamp(54px,5.7vw,84px); line-height:1.2; letter-spacing:-.055em; margin:17px 0 16px; font-weight:700; }
.launch-copy h1 em { color:var(--blue); }
.launch-description { font-size:18px; line-height:1.8; color:var(--muted); }
.launch-actions { display:flex; align-items:center; justify-content:center; gap:15px; margin-top:23px; }
.launch-trial-note { color:#718096; font-size:11px; margin-top:11px; line-height:1.8; }
.launch-gallery { position:relative; width:min(960px,100%); height:336px; margin:24px auto 0; }
.gallery-orbit { position:absolute; width:900px; height:200px; left:4%; top:75px; border:1px solid #2458f50c; border-radius:50%; transform:rotate(-11deg); }
.gallery-orbit::after { position:absolute; content:""; width:8px; height:8px; border-radius:50%; background:var(--warm); right:100px; bottom:4px; }
.hero-ohm,.hero-lever { position:absolute; overflow:hidden; background:#fff; border:1px solid #d9e3f4; border-radius:14px; box-shadow:0 24px 54px #192b4812,0 3px 8px #192b4806; text-align:left; }
.hero-ohm { width:46%; left:15%; top:3px; transform:rotate(-3deg); }
.launch-gallery figcaption { display:flex; align-items:center; justify-content:space-between; gap:10px; height:35px; padding:0 15px; font-size:10px; color:var(--muted); border-bottom:1px solid #edf1f7; }
.hero-ohm figcaption>span:last-child { color:var(--blue); font-size:16px; }
.window-dots { display:flex; gap:4px; }
.window-dots i { width:4px; height:4px; border-radius:50%; background:#cad5e8; }
.window-dots i:first-child { background:var(--warm); }
.hero-ohm-canvas { position:relative; aspect-ratio:1.5; overflow:hidden; background:#fbfcff; }
.hero-ohm-canvas img { position:absolute; width:153.191%; max-width:none; left:-13.8298%; top:-27.1429%; }
.hero-lever { width:43%; right:4%; top:100px; transform:rotate(3deg); }
.hero-lever img { aspect-ratio:2.25; object-fit:cover; object-position:center; }
.hero-next { display:inline-flex; align-items:center; gap:22px; min-height:44px; padding:8px 0 22px; color:var(--muted); font-size:12px; }
.hero-next>span { color:var(--blue); font-size:18px; }
.hero-next:hover { color:var(--blue); }

/* Two categories. Product claims stay close to the actual task and image. */
.tools-section { padding-top:100px; padding-bottom:94px; }
.assignment-product { display:grid; grid-template-columns:.85fr 1.15fr; gap:64px; align-items:center; padding-bottom:75px; }
.product-category { display:flex; align-items:center; gap:12px; color:var(--blue-dark); font-size:12px; letter-spacing:.04em; margin-bottom:22px; }
.product-category>span { color:#94a6c3; font-size:11px; }
.assignment-copy h3,.experiment-heading h3 { font-size:clamp(28px,2.8vw,36px); line-height:1.5; letter-spacing:-.04em; }
.product-description { max-width:410px; color:var(--muted); margin-top:22px; font-size:15px; line-height:2; }
.benefit-list { list-style:none; padding:0; margin:22px 0 25px; font-size:13px; line-height:2.2; }
.benefit-list li::before { content:"✓"; color:var(--blue); margin-right:11px; }
.product-actions { display:flex; flex-wrap:wrap; align-items:center; gap:20px; }
.product-actions .primary-action { font-size:14px; }
.assignment-figure { background:var(--paper); border:1px solid var(--line); border-radius:16px; padding:24px 24px 0; overflow:hidden; }
.electric-crop { position:relative; aspect-ratio:1.97; overflow:hidden; background:#fcfdf8; }
.electric-crop img { position:absolute; width:177.778%; max-width:none; left:-33.333%; top:-68.493%; height:auto; }
.assignment-figure .electric-crop { border-radius:9px; border:1px solid #dbe3ef; }
.assignment-figure figcaption { display:flex; justify-content:space-between; gap:15px; padding:17px 0; font-size:11px; color:var(--muted); }
.assignment-figure figcaption>span:first-child { color:var(--ink); }
.experiments-group { border-top:1px solid var(--line); padding-top:55px; }
.experiment-heading { display:flex; align-items:flex-end; justify-content:space-between; gap:40px; margin-bottom:34px; }
.experiment-heading-aside>p { color:var(--muted); font-size:15px; line-height:1.95; }
.more-experiments { margin-top:10px; min-height:44px; font-size:14px; }
.category-panel .all-experiments { border-top:1px solid var(--line); margin-top:5px; color:var(--blue-dark); }
.experiment-grid { display:grid; grid-template-columns:repeat(3,minmax(0,1fr)); gap:24px; }
.experiment-product { position:relative; isolation:isolate; min-width:0; border:1px solid var(--line); border-radius:14px; overflow:hidden; background:#fff; }
.experiment-entry::after { content:""; position:absolute; inset:0; z-index:1; border-radius:14px; cursor:pointer; }
.experiment-entry:focus-visible { outline:none; }
.experiment-entry:focus-visible::after { outline:3px solid #b96c29; outline-offset:-4px; }
.experiment-product:has(.experiment-entry:is(:hover,:focus-visible)) { border-color:#b9cbfa; }
.experiment-image { display:block; overflow:hidden; position:relative; aspect-ratio:1.38; background:#fbfcff; border-bottom:1px solid var(--line); }
.experiment-image img { position:absolute; max-width:none; }
.lever-image img { width:141%; left:-20%; top:12%; }
.ohm-image img { width:153.191%; left:-13.8298%; top:-27.1429%; }
.resistance-meter-image img { width:411.429%; left:-205.714%; top:-75%; }
.experiment-image-caption { position:absolute; bottom:12px; left:14px; padding:6px 10px; border:1px solid #dce5f2; border-radius:5px; background:#fffffff0; color:var(--ink); font-size:11px; }
.experiment-copy { padding:25px 25px 10px; }
.experiment-copy h4 { font-family:var(--display-font); font-weight:700; font-size:23px; line-height:1.5; letter-spacing:-.03em; }
.experiment-copy>p { min-height:3.8em; margin-top:11px; font-size:14px; color:var(--muted); line-height:1.9; }
.experiment-actions { display:flex; justify-content:space-between; align-items:center; margin-top:17px; gap:10px; }
.experiment-try { display:inline-flex; align-items:center; gap:12px; min-height:44px; color:var(--blue-dark); font-size:13px; }
.experiment-product:has(.experiment-entry:is(:hover,:focus-visible)) .experiment-try { text-decoration:underline; text-underline-offset:5px; }
.experiment-actions .quiet-link { position:relative; z-index:2; font-size:12px; }
.experiment-footnote { display:flex; justify-content:center; flex-wrap:wrap; align-items:center; gap:8px 15px; padding-top:19px; color:var(--muted); font-size:12px; line-height:1.9; }
.experiment-footnote a { display:inline-flex; align-items:center; gap:8px; min-height:44px; color:var(--blue-dark); }

/* One question, one illustrated result. Natural scrolling is never captured. */
.ai-section { padding:88px 0 45px; background:#f4f7fc; border-block:1px solid #e9eef8; }
.ai-heading { text-align:center; margin-bottom:42px; }
.ai-heading h2 { font-size:clamp(40px,4.5vw,60px); margin:15px 0 16px; line-height:1.3; }
.ai-heading h2 em { color:var(--blue); }
.ai-intro { font-size:18px; line-height:1.9; color:var(--muted); }
.ai-connection-flow { display:flex; align-items:center; justify-content:center; gap:0; padding:0; margin:31px auto 18px; max-width:790px; list-style:none; text-align:left; }
.ai-connection-flow li { position:relative; display:flex; align-items:center; gap:13px; flex:1; min-width:0; padding-right:36px; }
.ai-connection-flow li:last-child { flex:.93; padding-right:0; }
.ai-connection-flow li:not(:last-child)::after { content:"→"; position:absolute; right:16px; top:50%; transform:translateY(-50%); color:#9baecd; font-size:21px; }
.ai-connection-flow li>span { display:grid; place-items:center; flex:none; width:32px; height:32px; border:1px solid #d7e2f5; border-radius:50%; background:#fff; color:var(--blue-dark); font-size:11px; }
.ai-connection-flow strong { font-size:14px; line-height:1.85; font-weight:400; }
.ai-scope-note { color:var(--muted); font-size:12px; line-height:1.9; }
.story-runway { position:relative; }
.story-sticky { position:relative; }
.story-topline { display:flex; align-items:center; justify-content:space-between; gap:20px; margin-bottom:17px; }
.story-scene { color:var(--blue-dark); font-size:14px; font-weight:500; white-space:nowrap; }
.story-tabs { display:flex; gap:8px; }
.story-tabs button { border:1px solid transparent; background:transparent; padding:11px 20px; min-height:44px; border-radius:7px; color:var(--muted); font-size:13px; white-space:nowrap; }
.story-tabs button:hover { background:#e9effc; }
.story-tabs button[aria-selected="true"] { color:var(--blue); background:#fff; border-color:#dae4f8; box-shadow:0 3px 8px #192b4805; }
.story-counter { color:#91a0b8; font-size:12px; letter-spacing:.08em; }
.story-counter b { color:var(--ink); font-weight:500; }
.story-deck { overflow:clip; border-radius:16px; background:var(--soft-blue); border:1px solid #d9e3f4; box-shadow:0 14px 40px #192b4807; }
.story-case { display:grid; grid-template-columns:.88fr 1.35fr; min-height:468px; }
.story-question { padding:37px 35px 28px; display:flex; flex-direction:column; align-items:flex-start; }
.question-label { color:var(--blue-dark); font-size:14px; line-height:1.8; }
.story-question h3 { margin-top:20px; font-size:clamp(25px,2.5vw,34px); font-weight:700; line-height:1.6; letter-spacing:-.045em; }
.story-question>p { margin-top:17px; color:var(--muted); font-size:15px; line-height:1.9; }
.copy-question { display:inline-flex; align-items:center; gap:25px; min-height:44px; color:var(--blue-dark); background:transparent; margin-top:18px; padding:8px 0; font-size:13px; }
.copy-question:hover { text-decoration:underline; text-underline-offset:5px; }
.story-tip { margin-top:auto; padding-top:26px; }
.story-tip>span { color:#697b99; font-size:10px; letter-spacing:.03em; }
.story-tip p { color:var(--muted); font-size:12px; line-height:1.8; margin-top:7px; }
.story-result { min-width:0; padding:28px 32px 18px; background:#fff; display:flex; flex-direction:column; }
.result-topline { display:flex; justify-content:space-between; gap:12px; align-items:center; font-size:10px; color:var(--muted); }
.demo-label { color:var(--blue-dark); background:var(--soft-blue); border-radius:4px; padding:4px 7px; white-space:nowrap; font-size:10px; }
.story-result h4 { font-family:var(--display-font); font-size:26px; line-height:1.5; letter-spacing:-.03em; margin-top:23px; }
.result-intro { margin-top:10px; color:var(--muted); font-size:13px; line-height:1.8; }
.lesson-visual { display:grid; grid-template-columns:1fr 1fr; align-items:center; gap:23px; margin:22px 0 14px; flex:1; }
.circuit-reference img { max-width:280px; margin:auto; }
.circuit-reference>span { display:block; text-align:center; color:var(--muted); font-size:10px; line-height:1.8; margin-top:9px; }
.lesson-plan { margin:0; padding:0; list-style:none; }
.lesson-plan li { display:flex; align-items:center; gap:13px; padding:13px 0; border-top:1px solid var(--line); }
.lesson-plan li:first-child { border:0; }
.lesson-plan b { color:var(--blue); font-size:26px; font-weight:500; line-height:1; }
.lesson-plan b span { display:block; color:var(--muted); font-size:9px; font-weight:400; margin-top:7px; }
.lesson-plan strong { font-size:13px; font-weight:500; }
.lesson-plan p { font-size:11px; color:var(--muted); line-height:1.8; margin-top:4px; }
.result-evidence { display:flex; align-items:center; justify-content:space-between; gap:20px; min-height:44px; padding:12px 0; background:transparent; border-top:1px solid var(--line); color:var(--blue-dark); text-align:left; font-size:12px; margin-top:auto; }
.result-evidence:hover { color:var(--blue); }
.practice-comparison { display:grid; grid-template-columns:1fr 1fr; gap:14px; margin:25px 0 23px; }
.practice-person { padding:18px 17px 15px; border:1px solid var(--line); border-radius:9px; }
.student-initial { display:inline-flex; justify-content:center; align-items:center; width:32px; height:32px; border-radius:50%; background:var(--soft-blue); color:var(--blue-dark); font-size:13px; flex:none; }
.warm-initial { color:#a55f28; background:var(--soft-warm); }
.practice-topic { color:var(--muted); font-size:10px; margin-left:8px; }
.practice-person h5 { font-size:14px; font-weight:500; line-height:1.8; margin-top:14px; }
.practice-person>p { color:var(--muted); font-size:12px; line-height:1.85; margin-top:7px; }
.next-check { margin-top:17px; padding-top:12px; border-top:1px solid var(--line); }
.next-check>span { color:var(--blue-dark); font-size:10px; }
.next-check p { margin-top:5px; color:var(--muted); font-size:11px; line-height:1.8; }
.submission-visual { display:flex; align-items:center; gap:27px; margin:35px 0 25px; flex:1; }
.completion-ring { width:160px; aspect-ratio:1; flex:none; display:grid; place-items:center; background:conic-gradient(var(--blue) 0 66.6667%,var(--warm) 66.6667% 83.3333%,#e5ebf5 83.3333%); border-radius:50%; }
.completion-ring>div { display:flex; flex-direction:column; align-items:center; justify-content:center; width:136px; height:136px; border-radius:50%; background:#fff; }
.completion-ring strong { font-size:40px; font-weight:500; letter-spacing:-.05em; }
.completion-ring strong span { font-size:22px; color:#92a1b8; margin-left:5px; }
.completion-ring>div>span { color:var(--muted); font-size:12px; margin-top:9px; }
.pending-students { min-width:0; flex:1; }
.pending-students>div { display:flex; align-items:center; gap:10px; padding:21px 0; border-bottom:1px solid var(--line); }
.pending-students>div:last-child { border:0; }
.pending-students strong { font-size:13px; font-weight:500; }
.pending-students small { display:block; margin-top:6px; font-size:10px; color:var(--muted); line-height:1.8; }
.pending-students b { margin-left:auto; color:var(--muted); font-size:10px; font-weight:400; white-space:nowrap; }
.pending-students b.status-working { color:#a55f28; }
.submission-legend { display:flex; justify-content:center; gap:23px; margin-bottom:27px; color:var(--muted); font-size:11px; }
.submission-legend span { display:flex; align-items:center; gap:7px; }
.submission-legend i { width:6px; height:6px; border-radius:50%; background:var(--blue); }
.submission-legend span:nth-child(2) i { background:var(--warm); }
.submission-legend span:nth-child(3) i { background:#d8e1f0; }
.draft-preview { border:1px solid var(--line); border-radius:9px; padding:15px 18px; margin-top:20px; }
.draft-preview-heading { display:flex; justify-content:space-between; font-size:10px; color:var(--muted); }
.draft-preview-heading span:last-child { color:#a55f28; }
.draft-preview h5 { margin-top:12px; font-size:14px; font-weight:500; line-height:1.8; }
.draft-circuit { max-width:350px; margin:8px auto; }
.draft-checks { display:flex; flex-wrap:wrap; gap:8px; font-size:10px; color:var(--muted); margin-top:11px; }
.draft-checks span { border:1px solid var(--line); border-radius:4px; padding:5px 7px; }
.draft-note { font-size:11px; color:var(--muted); line-height:1.8; margin-top:12px; }
.story-bottomline { display:flex; align-items:center; justify-content:space-between; gap:18px; padding:14px 0 0; }
.story-bottomline>p { color:#718097; font-size:10px; line-height:1.8; }
.story-arrows { display:flex; gap:9px; }
.story-arrows button { width:44px; height:44px; border:1px solid #d7e1f3; background:#fff; border-radius:50%; font-size:20px; color:var(--blue-dark); }
.story-arrows button:enabled:hover { background:var(--soft-blue); }
.ai-exit { display:flex; justify-content:center; align-items:center; flex-wrap:wrap; gap:12px 25px; padding-top:36px; }
.ai-exit>span { font-size:14px; color:var(--muted); }

/* FAQ remains a place to scan and read, with no rotating content. */
.faq-section { display:grid; grid-template-columns:.7fr 1.3fr; gap:90px; padding-top:100px; padding-bottom:95px; }
.faq-intro .eyebrow { margin-bottom:18px; }
.faq-intro h2 { font-size:36px; }
.faq-intro .plain-link { margin-top:24px; }
.faq-list { border-top:1px solid var(--line); }
.faq-list details { border-bottom:1px solid var(--line); }
.faq-list summary { position:relative; padding:24px 30px 24px 0; min-height:70px; list-style:none; font-size:15px; line-height:1.8; cursor:pointer; }
.faq-list summary::-webkit-details-marker { display:none; }
.faq-list summary::after { content:"+"; position:absolute; right:2px; top:24px; color:var(--blue); font-size:20px; font-weight:400; line-height:1.25; }
.faq-list details[open]>summary { color:var(--blue-dark); }
.faq-list details[open]>summary::after { content:"−"; }
.faq-answer { padding:0 26px 23px 0; }
.faq-answer p { font-size:14px; color:var(--muted); line-height:2; }
.faq-answer .plain-link { font-size:12px; margin-top:10px; }
.more-faq>summary { color:var(--blue-dark); font-size:13px; }
.more-faq>summary>span { font-size:11px; color:var(--muted); margin-left:12px; }
.extra-questions { padding:0 20px 20px; background:var(--paper); border-radius:9px; margin-bottom:20px; }
.extra-questions details:last-child { border:0; }
.extra-questions summary { font-size:13px; }
.closing-section { background:var(--soft-blue); padding:65px 0; }
.closing-inner { display:flex; justify-content:space-between; align-items:center; gap:45px; }
.closing-inner h2 { margin-top:17px; font-size:clamp(31px,3.3vw,44px); }
.closing-action { display:flex; flex-direction:column; align-items:flex-start; gap:15px; }
.closing-action .quiet-link { font-size:12px; }
.site-footer { background:#fff; padding:36px 0 21px; }
.footer-top { display:flex; justify-content:space-between; align-items:center; gap:25px; }
.footer-brand { display:flex; align-items:center; gap:8px; }
.footer-brand img { width:30px; height:30px; }
.footer-brand strong { font-size:19px; }
.footer-top nav { display:flex; align-items:center; flex-wrap:wrap; gap:24px; }
.footer-top nav a,.footer-top nav button { display:inline-flex; align-items:center; min-height:44px; padding:0; background:transparent; font-size:12px; color:var(--muted); }
.footer-top nav a:hover,.footer-top nav button:hover { color:var(--blue); }
.footer-legal { display:flex; flex-wrap:wrap; justify-content:center; align-items:center; gap:6px 27px; border-top:1px solid var(--line); margin-top:22px; padding-top:17px; color:#748198; font-size:11px; line-height:1.8; }
.footer-legal a { display:inline-flex; align-items:center; min-height:44px; }
.footer-legal a:hover { color:var(--blue); }

/* Shared information dialogs and compact supporting pages. */
dialog { position:fixed; width:min(650px,calc(100% - 32px)); max-height:86svh; padding:42px 36px 30px; border:0; border-radius:16px; overflow:auto; color:var(--ink); background:#fff; box-shadow:0 20px 80px #10244f33; }
dialog::backdrop { background:#10203977; backdrop-filter:blur(3px); }
.dialog-close { position:absolute; right:10px; top:10px; width:44px; height:44px; border-radius:50%; background:var(--paper); color:var(--muted); font-size:25px; }
.dialog-close:hover { color:var(--blue); }
.dialog-eyebrow { color:var(--blue-dark); font-size:11px; letter-spacing:.04em; }
dialog h2 { margin:12px 0 18px; font-size:29px; }
#dialog-title:focus { outline:none; }
dialog p { color:var(--muted); font-size:14px; line-height:1.95; }
.dialog-steps { margin:23px 0; padding-left:21px; }
.dialog-steps li { padding-left:5px; margin-bottom:19px; font-size:14px; line-height:1.85; }
.dialog-steps strong { display:block; font-weight:500; }
.dialog-steps span { display:block; margin-top:6px; color:var(--muted); font-size:13px; }
.endpoint { display:flex; align-items:center; gap:14px; padding:14px 16px; background:var(--paper); border:1px solid var(--line); border-radius:8px; margin-top:22px; }
.endpoint code { font-size:11px; line-height:1.8; overflow-wrap:anywhere; flex:1; }
.endpoint button { min-height:44px; background:transparent; color:var(--blue-dark); font-size:12px; white-space:nowrap; }
.dialog-actions { display:flex; flex-wrap:wrap; align-items:center; gap:18px; margin-top:22px; }
.dialog-actions .primary-action { font-size:13px; }
dialog[data-view="ai"] { width:min(520px,calc(100% - 32px)); padding:39px 30px 25px; }
dialog[data-view="ai"] h2 { margin-bottom:12px; }
.series-connection-field { margin-top:22px; }
.series-connection-field textarea { display:block; width:100%; min-height:96px; resize:none; padding:12px 14px; border:1px solid var(--line); border-radius:8px; color:var(--ink); background:var(--paper); font:13px/1.8 "Microsoft YaHei",sans-serif; }
.series-connection-field textarea:focus-visible { outline:2px solid var(--blue); outline-offset:2px; }
.connection-copy-row { display:flex; align-items:center; gap:20px; margin-top:16px; }
.connection-copy-primary { flex:none; font-size:14px; padding-inline:17px; gap:18px; }
.connection-copy-row .assistant-copy-hint { font-size:13px; line-height:1.8; }
@media(max-width:540px) {
  dialog[data-view="ai"] { max-height:calc(100svh - 32px); padding:30px 22px 20px; }
  .series-connection-field { margin-top:16px; }
  .series-connection-field textarea { min-height:128px; font-size:12px; line-height:1.7; }
  .connection-copy-row { flex-direction:column; align-items:stretch; gap:9px; }
  .connection-copy-row .assistant-copy-hint br { display:none; }
}
.series-help-links { display:flex; flex-wrap:wrap; gap:0 22px; margin-top:15px; }
.series-help-links a { display:inline-flex; align-items:center; gap:7px; min-height:44px; color:var(--muted); font-size:12px; }
.series-help-links a:hover { color:var(--blue); }
.help-question { display:inline-flex; align-items:center; justify-content:center; width:15px; height:15px; border:1px solid currentColor; border-radius:50%; font-size:10px; }
dialog .dialog-note { margin-top:22px; border-top:1px solid var(--line); padding-top:17px; font-size:12px; line-height:1.9; }
.topic-preview-list { padding-left:20px; margin:20px 0; color:var(--muted); font-size:14px; line-height:2.2; }
.feedback-template { padding:17px 20px; background:var(--paper); border-radius:8px; }
.feedback-template>span { font-size:12px; }
.feedback-template pre { font:12px/2 "Microsoft YaHei",sans-serif; color:var(--muted); white-space:pre-wrap; }
.feedback-template button { font-size:12px; }
.prompt-text { display:block; width:100%; min-height:230px; margin-top:23px; padding:17px 18px; border:1px solid var(--line); border-radius:8px; background:var(--paper); color:var(--ink); font:14px/2 "Microsoft YaHei",sans-serif; resize:vertical; }
.prompt-text:focus-visible { outline:3px solid #b96c29; outline-offset:3px; }
.package-list { display:grid; gap:12px; margin:23px 0; }
.package-list a { display:flex; justify-content:space-between; align-items:center; gap:20px; padding:17px 20px; min-height:72px; border:1px solid var(--line); border-radius:8px; }
.package-list strong { display:block; font-size:14px; font-weight:500; }
.package-list small { display:block; font-size:11px; line-height:1.8; color:var(--muted); margin-top:5px; }
.package-list a>span:last-child { color:var(--blue); font-size:24px; }
.package-list a:hover { border-color:var(--blue); background:var(--paper); }
.evidence-table { width:100%; border-collapse:collapse; font-size:12px; text-align:left; margin:23px 0; }
.evidence-table th,.evidence-table td { padding:10px 9px; border-bottom:1px solid var(--line); line-height:1.8; }
.evidence-table th { color:var(--muted); font-weight:400; font-size:11px; }
.evidence-table td { color:var(--muted); }
.evidence-table .needs-review { color:#a55f28; }
.toast { position:fixed; bottom:22px; left:50%; transform:translateX(-50%); z-index:70; width:max-content; max-width:calc(100% - 32px); border-radius:9px; background:var(--ink); color:#fff; padding:13px 20px; font-size:13px; line-height:1.8; box-shadow:0 8px 28px #192b4826; }
.document-header { border-bottom:1px solid var(--line); }
.document-header .header-inner { justify-content:space-between; }
.document-header .plain-link { font-size:13px; }
.document-main { width:calc(100% - 48px); max-width:820px; margin:60px auto 90px; }
.document-main h1 { font-family:var(--display-font); font-size:42px; line-height:1.5; margin:12px 0 18px; letter-spacing:-.04em; }
.document-main .document-lead { color:var(--muted); font-size:16px; line-height:1.95; }
.document-main section { margin-top:38px; padding-top:29px; border-top:1px solid var(--line); }
.document-main h2 { font-size:24px; margin-bottom:13px; }
.document-main p,.document-main li { font-size:15px; line-height:2; color:var(--muted); }
.document-main p+p { margin-top:14px; }
.document-main ul,.document-main ol { padding-left:22px; margin:14px 0; }
.document-main .plain-link { font-size:14px; }
.draft-notice { padding:19px 23px; background:var(--soft-warm); border-radius:9px; margin:25px 0; font-size:13px!important; }
.document-tool-links { display:flex; flex-wrap:wrap; gap:12px; margin-top:23px; }
.document-tool-links a { padding:13px 17px; border:1px solid var(--line); border-radius:8px; font-size:13px; min-height:46px; }
.document-tool-links a:hover { color:var(--blue); border-color:var(--blue); }

@media(min-width:1600px) {
  .launch-hero { padding-top:56px; }
  .launch-gallery { width:1080px; height:380px; margin-top:30px; }
  .hero-lever { top:120px; }
}
@media(max-width:1150px) {
  .header-inner { gap:20px; padding-inline:25px; }
  .content-nav { gap:17px; font-size:12px; }
  .quick-nav { gap:15px; }
  .quick-link { font-size:11px; }
  .account-entry { font-size:12px; padding-left:18px; }
  .assignment-product { gap:40px; }
  .experiment-copy { padding-inline:20px; }
  .experiment-copy h4 { font-size:21px; }
  .story-question { padding:31px 28px; }
  .story-result { padding:26px 25px 17px; }
  .lesson-visual { gap:18px; }
  .practice-person { padding:15px 13px; }
  .submission-visual { gap:19px; }
  .completion-ring { width:135px; }
  .completion-ring>div { width:113px; height:113px; }
  .faq-section { gap:60px; }
}
@media(max-width:1050px) {
  .content-nav { display:none; }
  .quick-nav { margin-left:auto; }
}
@media(min-width:1000px) and (min-height:700px) and (prefers-reduced-motion:no-preference) {
  .story-runway.is-scroll-story { height:calc(min(620px,100svh - var(--header-height) - 36px) + 210vh); }
  .is-scroll-story .story-sticky { position:sticky; top:calc(var(--header-height) + 18px); height:min(620px,calc(100svh - var(--header-height) - 36px)); display:flex; flex-direction:column; }
  .is-scroll-story .story-deck { flex:1; min-height:0; }
  .is-scroll-story .story-case { height:100%; min-height:0; }
  .is-scroll-story .story-question { padding-top:29px; padding-bottom:23px; }
  .is-scroll-story .story-question h3 { margin-top:15px; }
  .is-scroll-story .story-result { padding-top:23px; }
  .is-scroll-story .story-result h4 { margin-top:18px; }
  .is-scroll-story .lesson-visual { margin-top:13px; margin-bottom:9px; }
  .is-scroll-story .practice-comparison { margin-top:19px; margin-bottom:18px; }
  .is-scroll-story .submission-visual { margin-top:25px; margin-bottom:15px; }
  .is-scroll-story .submission-legend { margin-bottom:20px; }
  .is-scroll-story .draft-preview { margin-top:13px; }
  .is-scroll-story .draft-circuit { max-width:285px; }
  .story-case.is-entering { animation:case-push .38s cubic-bezier(.2,.7,.2,1) both; }
}
@media(max-width:950px) {
  .section-wrap { width:calc(100% - 64px); }
  .header-inner { gap:17px; }
  .quick-link { font-size:11px; }
  .account-entry { font-size:11px; }
  .brand-type strong { font-size:21px; }
  .launch-copy h1 { font-size:60px; }
  .launch-gallery { height:315px; }
  .hero-ohm { width:52%; left:5%; }
  .hero-lever { width:48%; right:0; top:115px; }
  .assignment-product { grid-template-columns:1fr 1.1fr; gap:30px; }
  .assignment-copy h3,.experiment-heading h3 { font-size:30px; }
  .assignment-figure { padding:16px 16px 0; }
  .product-description { font-size:14px; }
  .benefit-list { font-size:12px; }
  .product-actions { gap:13px; }
  .product-actions .primary-action { padding-inline:17px; font-size:12px; gap:15px; }
  .product-actions .plain-link { font-size:12px; }
  .experiment-grid { gap:16px; }
  .experiment-copy { padding:20px 18px 9px; }
  .experiment-copy h4 { font-size:19px; }
  .experiment-copy>p { font-size:12px; }
  .experiment-copy>p br { display:none; }
  .experiment-actions { flex-wrap:wrap; gap:0 12px; margin-top:11px; }
  .ai-connection-flow { max-width:680px; }
  .ai-connection-flow strong { font-size:13px; }
  .ai-connection-flow li { gap:10px; padding-right:31px; }
  .ai-connection-flow li:not(:last-child)::after { right:11px; }
  .story-topline { gap:12px; }
  .story-scene { font-size:12px; }
  .story-tabs { gap:3px; }
  .story-tabs button { padding-inline:13px; font-size:12px; }
  .story-case { grid-template-columns:.85fr 1.25fr; }
  .story-question { padding:28px 23px; }
  .story-question h3 { font-size:27px; }
  .story-question>p { font-size:14px; }
  .story-result { padding:24px 23px 15px; }
  .story-result h4 { font-size:23px; }
  .lesson-visual { grid-template-columns:1fr; gap:0; margin-top:9px; }
  .circuit-reference img { max-width:230px; }
  .lesson-plan { display:flex; gap:14px; margin-top:16px; }
  .lesson-plan li { flex:1; flex-direction:column; align-items:flex-start; gap:9px; border:0; padding:0; }
  .lesson-plan b { display:flex; align-items:baseline; gap:4px; font-size:22px; }
  .lesson-plan b span { display:inline; margin:0; }
  .lesson-plan p { font-size:10px; }
  .result-evidence { margin-top:22px; }
  .practice-comparison { grid-template-columns:1fr; }
  .practice-person { display:grid; grid-template-columns:32px 1fr; gap:0 10px; }
  .practice-topic { margin:5px 0; }
  .practice-person h5,.practice-person>p,.next-check { grid-column:2; }
  .practice-person h5 { margin-top:3px; }
  .next-check { margin-top:10px; padding-top:9px; }
  .submission-visual { flex-direction:column; gap:13px; margin-top:25px; }
  .pending-students { width:100%; }
  .pending-students>div { padding:16px 0; }
  .submission-legend { gap:12px; font-size:10px; }
  .faq-section { grid-template-columns:.8fr 1.2fr; gap:35px; }
  .faq-intro h2 { font-size:31px; }
  .faq-list summary { font-size:14px; }
}
@media(max-width:640px) {
  :root { --header-height:110px; }
  .header-inner { flex-wrap:wrap; gap:8px 16px; min-height:0; padding:11px 20px 0; }
  .brand-symbol { width:31px; height:31px; }
  .brand-type strong { font-size:21px; }
  .brand-type small { font-size:8px; letter-spacing:.03em; margin-top:4px; }
  .account-entry { margin-left:auto; min-height:44px; border:0; padding:0; font-size:12px; gap:8px; }
  .quick-nav { position:relative; order:2; width:100%; border-top:1px solid #edf1f7; justify-content:space-between; gap:0; margin:0; }
  .quick-link { font-size:11px; padding:8px 0; }
  .quick-link>span:last-child { font-size:13px; }
  .nav-category { position:static; }
  .category-panel { left:0; right:0; width:auto; }
  .section-wrap { width:calc(100% - 40px); }
  .launch-hero { padding:31px 20px 0; }
  .launch-eyebrow { font-size:11px; gap:8px; }
  .launch-copy h1 { font-size:clamp(41px,11.8vw,60px); margin:20px 0 17px; line-height:1.32; }
  .launch-copy h1 em { display:block; }
  .launch-description { font-size:14px; line-height:1.9; }
  .phone-break { display:block; }
  .launch-actions { margin-top:23px; gap:11px; }
  .launch-actions .primary-action,.launch-actions .secondary-action { min-height:50px; padding:12px 15px; font-size:12px; gap:17px; }
  .launch-trial-note { margin-top:10px; font-size:10px; }
  .launch-gallery { height:265px; margin-top:27px; }
  .hero-ohm { width:64%; left:0; top:0; border-radius:10px; }
  .hero-lever { width:59%; right:-1%; top:122px; border-radius:10px; }
  .launch-gallery figcaption { height:30px; padding:0 10px; font-size:8px; gap:6px; }
  .hero-lever img { aspect-ratio:1.85; }
  .gallery-orbit { width:540px; height:150px; left:-90px; top:65px; }
  .window-dots { display:none; }
  .hero-next { padding-bottom:17px; font-size:10px; gap:20px; }
  .tools-section { padding-top:58px; padding-bottom:49px; }
  h2 { font-size:32px; }
  .eyebrow { font-size:11px; }
  .section-heading { margin-bottom:34px; }
  .section-heading .eyebrow { margin-bottom:15px; }
  .assignment-product { grid-template-columns:1fr; gap:27px; padding-bottom:44px; }
  .product-category { font-size:11px; margin-bottom:16px; }
  .assignment-copy h3,.experiment-heading h3 { font-size:29px; }
  .product-description { font-size:14px; margin-top:17px; max-width:none; }
  .benefit-list { margin-top:18px; margin-bottom:19px; font-size:12px; }
  .product-actions { gap:21px; }
  .product-actions .primary-action { font-size:13px; }
  .assignment-figure { border-radius:12px; padding:16px 16px 0; }
  .assignment-figure figcaption { font-size:9px; padding:13px 0; }
  .experiments-group { padding-top:35px; }
  .experiment-heading { display:block; margin-bottom:27px; }
  .experiment-heading-aside>p { font-size:13px; margin-top:15px; }
  .experiment-grid { grid-template-columns:1fr; gap:21px; }
  .experiment-image { aspect-ratio:1.65; }
  .resistance-meter-image img { width:360%; left:-177.5%; top:-80%; }
  .experiment-copy { padding:23px 24px 11px; }
  .experiment-copy h4 { font-size:23px; }
  .experiment-copy>p { font-size:14px; line-height:1.85; }
  .experiment-copy>p br { display:block; }
  .experiment-actions { margin-top:16px; }
  .experiment-actions .quiet-link { font-size:12px; }
  .experiment-footnote { font-size:10px; padding-top:16px; gap:0 10px; }
  .ai-section { padding-top:53px; padding-bottom:32px; }
  .ai-heading { text-align:left; margin-bottom:29px; }
  .ai-heading h2 { font-size:clamp(33px,8.9vw,40px); margin-top:14px; margin-bottom:15px; }
  .ai-intro { font-size:14px; max-width:23em; }
  .ai-connection-flow { display:block; margin:23px 0 16px; }
  .ai-connection-flow li,.ai-connection-flow li:last-child { padding:0 0 21px; gap:12px; }
  .ai-connection-flow li:last-child { padding-bottom:0; }
  .ai-connection-flow li:not(:last-child)::after { content:""; left:15px; top:34px; width:1px; height:17px; transform:none; background:#d7e2f5; }
  .ai-connection-flow strong { font-size:13px; }
  .ai-connection-flow br { display:none; }
  .ai-connection-flow li>span { width:31px; height:31px; font-size:10px; }
  .ai-scope-note { font-size:11px; max-width:27em; }
  .story-topline { display:grid; grid-template-columns:1fr; gap:12px; margin-bottom:12px; }
  .story-scene { font-size:13px; }
  .story-tabs { flex:1; display:grid; grid-template-columns:repeat(4,minmax(0,1fr)); gap:3px; }
  .story-tabs button { font-size:10px; padding:10px 5px; min-height:44px; }
  .story-counter { display:none; }
  .story-deck { border-radius:12px; }
  .story-case { display:block; min-height:0; }
  .story-question { padding:25px 23px 23px; display:block; }
  .question-label { font-size:13px; }
  .story-question h3 { margin-top:12px; font-size:26px; line-height:1.5; }
  .story-question>p { margin-top:11px; font-size:13px; }
  .story-question>p br { display:none; }
  .copy-question { font-size:11px; margin-top:11px; }
  .story-tip { padding-top:16px; margin-top:7px; border-top:1px solid #d8e2f6; }
  .story-tip>span { font-size:9px; }
  .story-tip p { font-size:11px; margin-top:4px; }
  .story-result { padding:23px 22px 13px; }
  .result-topline { font-size:9px; gap:8px; }
  .demo-label { font-size:9px; }
  .story-result h4 { font-size:23px; margin-top:18px; }
  .result-intro { font-size:12px; margin-top:9px; }
  .lesson-visual { display:block; margin:15px 0 20px; }
  .circuit-reference img { max-width:260px; }
  .circuit-reference>span { font-size:9px; margin-top:5px; }
  .lesson-plan { display:block; margin-top:19px; }
  .lesson-plan li { display:flex; flex-direction:row; align-items:center; padding:12px 0; border-top:1px solid var(--line); gap:14px; }
  .lesson-plan li:first-child { border-top:1px solid var(--line); }
  .lesson-plan b { font-size:25px; width:34px; display:block; }
  .lesson-plan b span { display:block; margin-top:5px; font-size:9px; }
  .lesson-plan strong { font-size:13px; }
  .lesson-plan p { font-size:11px; }
  .result-evidence { font-size:11px; margin-top:0; }
  .practice-comparison { margin-top:20px; margin-bottom:22px; gap:12px; }
  .practice-person { padding:17px 15px; }
  .practice-person>p br { display:none; }
  .practice-person h5 { font-size:14px; }
  .practice-person>p { font-size:12px; }
  .submission-visual { display:block; margin:24px 0 14px; }
  .completion-ring { width:150px; margin:auto auto 10px; }
  .completion-ring>div { width:126px; height:126px; }
  .submission-legend { font-size:9px; margin-bottom:20px; gap:17px; }
  .draft-preview { padding:14px; }
  .draft-preview h5 { font-size:13px; }
  .draft-note { margin-bottom:8px; }
  .story-bottomline { padding-top:11px; gap:10px; }
  .story-bottomline>p { font-size:9px; max-width:190px; }
  .story-arrows { gap:7px; }
  .ai-exit { justify-content:flex-start; gap:0 12px; padding-top:25px; }
  .ai-exit>span { font-size:12px; }
  .ai-exit .plain-link { font-size:12px; }
  .faq-section { display:block; padding-top:55px; padding-bottom:52px; }
  .faq-intro h2 { font-size:31px; }
  .faq-intro .plain-link { font-size:12px; margin-top:12px; margin-bottom:20px; }
  .faq-list summary { font-size:13px; padding-top:21px; padding-bottom:21px; min-height:64px; }
  .faq-list summary::after { top:21px; }
  .faq-answer { padding-right:10px; padding-bottom:21px; }
  .faq-answer p { font-size:13px; }
  .more-faq>summary { font-size:12px; }
  .more-faq>summary>span { font-size:10px; margin-left:8px; }
  .extra-questions { padding-inline:15px; }
  .extra-questions summary { font-size:12px; }
  .closing-section { padding:43px 0 37px; }
  .closing-inner { display:block; }
  .closing-inner h2 { font-size:29px; margin-top:15px; }
  .closing-action { gap:10px; margin-top:24px; }
  .closing-action .primary-action { font-size:13px; }
  .closing-action .quiet-link { font-size:11px; }
  .site-footer { padding-top:27px; padding-bottom:13px; }
  .footer-top { display:block; }
  .footer-brand strong { font-size:19px; }
  .footer-top nav { gap:0 23px; margin-top:16px; }
  .footer-top nav a,.footer-top nav button { font-size:11px; }
  .footer-legal { flex-direction:column; gap:0; margin-top:16px; padding-top:19px; font-size:10px; }
  dialog { padding:39px 24px 25px; }
  dialog h2 { font-size:25px; }
  dialog p { font-size:13px; }
  .dialog-steps { font-size:13px; }
  .dialog-steps span { font-size:12px; }
  .endpoint { display:block; padding:13px 16px 7px; }
  .endpoint code { display:block; font-size:10px; }
  .endpoint button { font-size:11px; }
  .evidence-table { font-size:10px; }
  .evidence-table th,.evidence-table td { padding:9px 5px; }
  .document-header .header-inner { flex-wrap:nowrap; padding-bottom:11px; }
  .document-header .plain-link { font-size:11px; }
  .document-main { margin-top:33px; margin-bottom:55px; }
  .document-main h1 { font-size:31px; }
  .document-main .document-lead { font-size:14px; }
  .document-main h2 { font-size:22px; }
  .document-main p,.document-main li { font-size:13px; }
  .draft-notice { padding:16px 18px; font-size:12px!important; }
}
@media(prefers-reduced-motion:no-preference) {
  .nav-chevron { transition:transform .18s ease; }
  .launch-copy { animation:hero-enter .55s ease-out both; }
  .launch-gallery { animation:hero-enter .7s .05s ease-out both; }
  .primary-action,.secondary-action,.experiment-product { transition:transform .2s ease,box-shadow .2s ease,background-color .18s ease; }
  .primary-action:hover,.secondary-action:hover { transform:translateY(-2px); }
  .experiment-product:has(.experiment-entry:is(:hover,:focus-visible)) { transform:translateY(-3px); box-shadow:0 14px 30px #192b4809; }
}
@media(prefers-reduced-motion:reduce) { html { scroll-behavior:auto; } }
@keyframes hero-enter { from { opacity:0; transform:translateY(10px); } to { opacity:1; transform:translateY(0); } }
@keyframes case-push { from { opacity:0; transform:translateX(26px) scale(.985); } to { opacity:1; transform:translateX(0) scale(1); } }