:root {
  color-scheme: light;
  --night: #071b26;
  --night-raised: #0b2633;
  --paper: #f3f8fa;
  --white: #fff;
  --ink: #092733;
  --muted: #47626d;
  --line: #cadde1;
  --teal: #00665e;
  --mint: #8cebd7;
  --blue: #96cfff;
  --light-muted: #bfd5dd;
  --wrap: 1184px;
  --font: 'Instrument Sans', 'Avenir Next', -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Microsoft YaHei', sans-serif;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 16px/1.65 var(--font); }
a { color: inherit; }
img { display: block; max-width: 100%; height: auto; }
figure, h1, h2, h3, p { margin: 0; }
h1, h2, h3 { line-height: 1.12; }
h1, h2 { letter-spacing: -.047em; }
:lang(zh-Hans) h1, :lang(zh-Hans) h2 { letter-spacing: -.045em; }
:focus-visible { outline: 3px solid #158ad1; outline-offset: 5px; }
.night :focus-visible { outline-color: var(--blue); }
[id] { scroll-margin-top: 1.5rem; }
.wrap { width: min(calc(100% - 80px), var(--wrap)); margin-inline: auto; }
.night { background: var(--night); color: #f3fcff; }
.skip { position: absolute; left: 1rem; top: 1rem; z-index: 3; padding: .55rem 1rem; background: var(--white); color: var(--ink); transform: translateY(-180%); }
.skip:focus { transform: translateY(0); }
.header { border-bottom: 1px solid #28414d; }
.header-inner { display: flex; min-height: 74px; align-items: center; justify-content: space-between; gap: 20px; }
.brand { display: inline-flex; width: fit-content; align-items: center; gap: 11px; font-size: 1.22rem; font-weight: 750; text-decoration: none; white-space: nowrap; }
.brand img { width: 37px; border-radius: 10px; }
.nav { display: flex; align-items: center; gap: clamp(15px, 2.8vw, 39px); }
.nav a, .language { color: var(--light-muted); font-size: .89rem; font-weight: 650; text-decoration: none; white-space: nowrap; }
.nav a:hover, .nav a[aria-current], .language:hover { color: var(--mint); }
.language { display: inline-flex; align-items: center; justify-content: center; border: 1px solid #415d67; padding: 7px 13px; border-radius: 8px; }
.hero { overflow: hidden; }
.hero-grid { display: grid; grid-template-columns: 1fr 1fr; align-items: center; min-height: 650px; gap: clamp(26px, 5vw, 76px); padding-block: 57px 48px; }
.hero-text { position: relative; z-index: 1; }
.hero-label { color: var(--mint); font-size: .95rem; font-weight: 650; margin-bottom: 20px; }
.hero h1 { font-size: clamp(3.1rem, 5.85vw, 5.35rem); font-weight: 760; line-height: 1.02; }
:lang(en) .hero h1 { font-size: clamp(2.55rem, 5vw, 4.5rem); }
.hero h1 span { display: block; }
.hero h1 span + span { color: var(--mint); margin-top: .075em; }
.hero-copy { color: var(--light-muted); font-size: clamp(1rem, 1.55vw, 1.21rem); line-height: 1.65; max-width: 41ch; margin-top: 23px; }
.actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 27px; }
.button { display: inline-flex; justify-content: center; align-items: center; gap: 13px; min-height: 47px; padding: 9px 19px; border: 1px solid transparent; border-radius: 9px; background: var(--mint); color: var(--night); font-size: .92rem; font-weight: 750; text-decoration: none; }
.button:hover { background: #b0f5e7; }
.button.secondary { border-color: #466570; background: #0e2b38; color: #effafd; }
.button.secondary:hover { border-color: #91c6cd; background: #163b48; }
.button.on-light { color: #fff; background: var(--teal); }
.button.on-light:hover { background: #075049; }
.hero-meta { color: #a5c4cf; font-size: .82rem; margin-top: 17px; }
.hero-meta span + span::before { content: '·'; padding-inline: .55em; }
.stage { position: relative; isolation: isolate; margin: 0; min-width: 0; }
.stage-art { position: relative; min-height: 550px; }
.stage-art::before { content: ''; position: absolute; z-index: -2; inset: 1% -15% 2% -8%; background: radial-gradient(ellipse at 54% 45%, #1a5662, #0c2e3e 49%, transparent 73%); }
.stage-art::after { content: ''; position: absolute; z-index: -1; inset: 0; background-image: radial-gradient(#87c8d35e .9px, transparent .9px); background-size: 20px 20px; mask-image: radial-gradient(ellipse, #000 25%, transparent 73%); }
.phone { overflow: hidden; background: #f2f3f7; border: 6px solid #061721; border-radius: 29px; box-shadow: 0 0 0 1px #4b6974, 0 20px 39px #030f1a80; }
.stage .phone { position: absolute; width: min(43%, 215px); }
.stage .phone-front { left: 15%; top: 2%; transform: rotate(-8deg); }
.stage .phone-back { right: 3%; top: 10%; transform: rotate(9deg); border-color: #132e3a; }
.stage figcaption { color: #abc9d3; font-size: .76rem; text-align: center; margin-top: 13px; }
.section { padding-block: clamp(60px, 8vw, 111px); }
.section-head { margin-bottom: 33px; }
.section-head h2, .formula h2, .end-panel h2 { font-size: clamp(2.05rem, 4vw, 3.7rem); font-weight: 750; text-wrap: balance; }
.section-head p { max-width: 65ch; margin-top: 12px; color: var(--muted); }
.feature-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.feature { padding: clamp(23px, 4vw, 43px) clamp(14px, 4.2vw, 54px); }
.feature:nth-child(odd) { padding-left: 0; border-right: 1px solid var(--line); }
.feature:nth-child(even) { padding-right: 0; }
.feature:nth-child(n+3) { border-top: 1px solid var(--line); }
.feature-mark { display: grid; width: 46px; height: 37px; place-items: center; border-radius: 8px; background: #dceff0; color: #075a57; font-weight: 800; line-height: 1; font-size: .8rem; margin-bottom: 19px; }
.feature h3 { font-size: clamp(1.24rem, 2vw, 1.64rem); margin-bottom: 9px; }
.feature p { max-width: 54ch; color: var(--muted); }
.formula { display: grid; grid-template-columns: .95fr 1.05fr; align-items: center; gap: clamp(22px, 5.5vw, 78px); padding: clamp(26px, 5.1vw, 71px); border-radius: 24px; background: var(--night-raised); color: #f3fcff; }
.formula p { color: var(--light-muted); margin-top: 16px; }
.formula small { display: block; color: var(--light-muted); font-size: .82rem; margin-top: 15px; }
.formula-values { display: grid; grid-template-columns: 1fr 1fr; gap: 12px 21px; }
.formula-values div { min-width: 0; }
.formula-values strong { display: block; font-size: clamp(1.7rem, 4.1vw, 3.6rem); line-height: 1.18; letter-spacing: -.055em; font-variant-numeric: tabular-nums; }
.formula-values span { color: var(--light-muted); font-size: .86rem; }
.formula-values .equivalent strong { color: var(--mint); }
.formula-values .distance-track { display: block; height: 8px; margin-top: 9px; border-radius: 5px; background: #2c4651; }
.distance-track::before { content: ''; display: block; width: 83.333%; height: 100%; border-radius: inherit; background: #87bdf0; }
.equivalent .distance-track::before { width: 100%; background: var(--mint); }
.formula-equation { grid-column: 1 / -1; font-size: .87rem; color: var(--light-muted); }
.gallery { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: clamp(16px, 2.5vw, 32px); }
.gallery figure { min-width: 0; }
.gallery-image { display: grid; place-items: center; padding: clamp(15px, 2.65vw, 35px); border: 1px solid #cce1e4; border-radius: 17px; background: #dfedf1; }
.gallery figure:nth-child(2) .gallery-image { background: #e1ecf6; }
.gallery figure:nth-child(3) .gallery-image { background: #dceeea; }
.gallery-image:hover { border-color: #35908f; }
.gallery-image img { width: 100%; max-width: 226px; border: 1px solid #8eacb4; border-radius: 17px; box-shadow: 0 10px 18px #09273320; }
.gallery h3 { font-size: 1.18rem; margin-block: 15px 6px; }
.gallery p { color: var(--muted); font-size: .92rem; }
.end-panel { display: grid; grid-template-columns: 1fr auto; align-items: center; gap: 24px; margin-bottom: 76px; padding: clamp(24px, 5vw, 53px); border-radius: 18px; background: #dcefeb; }
.end-panel h2 { font-size: clamp(1.65rem, 3.2vw, 2.75rem); }
.end-panel p { margin-top: 10px; color: var(--muted); max-width: 63ch; }
.footer { padding-block: 42px 21px; }
.footer-main { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 24px; padding-bottom: 28px; }
.footer-main p, .footer-bottom { color: var(--light-muted); font-size: .88rem; }
.footer-main p { margin-top: 9px; }
.footer-links { display: flex; align-items: center; flex-wrap: wrap; gap: 12px 25px; }
.footer-links a { color: var(--light-muted); font-size: .88rem; }
.footer-links a:hover { color: var(--mint); }
.footer-bottom { border-top: 1px solid #28414d; padding-top: 18px; }
.page-head { padding-block: clamp(53px, 7.5vw, 94px); background: radial-gradient(ellipse at 90% 30%, #113b49, var(--night) 58%); }
.page-head h1 { font-size: clamp(2.7rem, 6.4vw, 5rem); }
.page-head p { max-width: 65ch; margin-top: 15px; color: var(--light-muted); }
.page-head time { display: inline-block; margin-top: 14px; color: var(--mint); font-size: .9rem; }
.document { display: grid; grid-template-columns: minmax(155px, 220px) minmax(0, 750px); gap: clamp(25px, 6vw, 80px); align-items: start; }
.toc { position: sticky; top: 25px; border-left: 2px solid #9fcbc6; padding-left: 16px; }
.toc strong { display: block; margin-bottom: 9px; }
.toc ul { list-style: none; padding: 0; margin: 0; }
.toc a { display: block; width: fit-content; padding-block: 4px; color: var(--teal); font-size: .91rem; }
.document-content > section + section { border-top: 1px solid var(--line); margin-top: 28px; padding-top: 27px; }
.document-content h2, .support-layout h2, .faq h2 { font-size: clamp(1.36rem, 2.6vw, 2rem); margin-bottom: 12px; }
.document-content p, .document-content li, .support-layout p, .support-layout li, .faq p { color: var(--muted); }
.document-content p + p { margin-top: 12px; }
.document-content ul { padding-left: 1.2em; }
.document-content li + li { margin-top: 9px; }
.document-content a, .support-layout a { color: var(--teal); overflow-wrap: anywhere; }
.support-layout { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-bottom: 56px; }
.support-layout > section { background: var(--white); border: 1px solid var(--line); border-radius: 16px; padding: clamp(21px, 3.4vw, 37px); }
.support-layout p + p { margin-top: 12px; }
.support-layout ol { padding-left: 1.2em; margin-bottom: 0; }
.support-layout li + li { margin-top: 8px; }
.faq { max-width: 800px; }
.faq details { border-block-start: 1px solid var(--line); }
.faq details:last-child { border-block-end: 1px solid var(--line); }
.faq summary { list-style: none; display: flex; align-items: center; justify-content: space-between; gap: 12px; cursor: pointer; padding-block: 16px; font-weight: 680; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: '+'; color: var(--teal); font-size: 1.35rem; line-height: 1; }
.faq details[open] summary::after { content: '−'; }
.faq details p { padding: 0 23px 18px 0; }
.missing { max-width: 690px; }
.missing h1 { font-size: clamp(2rem, 5vw, 4rem); }
.missing p { margin-block: 14px 22px; color: var(--muted); }
@media (max-width: 1000px) {
  .hero-grid { min-height: 525px; }
  .stage-art { min-height: 0; aspect-ratio: .91; }
  .hero h1 { font-size: clamp(2.45rem, 6.1vw, 4.65rem); }
}
@media (max-width: 740px) {
  .wrap { width: calc(100% - 44px); }
  .hero-grid { grid-template-columns: 1fr; padding-block: 44px 30px; gap: 20px; }
  .hero h1 { font-size: clamp(2.65rem, 8.6vw, 4.2rem); }
  :lang(en) .hero h1 { font-size: clamp(2.45rem, 8vw, 4.2rem); }
  .hero-copy { margin-top: 16px; }
  .stage { width: min(100%, 480px); margin-inline: auto; }
  .stage-art { aspect-ratio: .91; }
  .stage .phone { width: 43%; }
  .stage .phone-front { left: 13%; }
  .stage .phone-back { right: 9%; }
  .formula { grid-template-columns: 1fr; }
  .end-panel { grid-template-columns: 1fr; margin-bottom: 51px; }
  .end-panel .button { justify-self: start; }
  .document { grid-template-columns: 1fr; }
  .toc { position: static; }
  .toc ul { display: flex; flex-wrap: wrap; gap: 3px 18px; }
}
@media (max-width: 530px) {
  .wrap { width: calc(100% - 34px); }
  .header-inner { display: grid; grid-template-columns: 1fr auto; min-height: 0; gap: 10px; padding-block: 12px 11px; }
  .brand { font-size: 1.12rem; }
  .brand img { width: 33px; }
  .nav { grid-row: 2; grid-column: 1 / -1; flex-wrap: wrap; gap: 4px 20px; }
  .nav a { padding-block: 4px; font-size: .84rem; }
  .language { grid-column: 2; grid-row: 1; font-size: .82rem; }
  .hero-grid { padding-top: 37px; }
  .hero-label { margin-bottom: 14px; }
  .hero h1 { font-size: clamp(2.31rem, 9vw, 3.45rem); }
  :lang(en) .hero h1 { font-size: clamp(2.15rem, 8.7vw, 3.25rem); }
  .phone { border-width: 4px; border-radius: 20px; }
  .gallery, .feature-grid, .support-layout { grid-template-columns: 1fr; }
  .gallery { gap: 27px; }
  .feature, .feature:nth-child(odd), .feature:nth-child(even) { padding: 23px 0; border-right: 0; }
  .feature + .feature { border-top: 1px solid var(--line); }
  .feature-mark { margin-bottom: 12px; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }