/**
 * 51｜耐力赛维修卡视觉系统。
 * 沥青黑、计时纸白、荧光黄绿与安全橙；非对称维修区看板，不使用通用圆角卡片。
 */
:root {
  --asphalt: #09110f;
  --asphalt-2: #101b18;
  --asphalt-3: #182622;
  --paper: #ece9df;
  --paper-deep: #ddd8c9;
  --ink: #14201d;
  --muted: #8d9994;
  --lime: #d9ff43;
  --orange: #ff6240;
  --steel: #6f7d78;
  --line-dark: rgba(236, 233, 223, .18);
  --line-light: rgba(20, 32, 29, .18);
  --shadow: 0 26px 80px rgba(0, 0, 0, .24);
  --display: "Noto Serif SC", "Songti SC", STSong, serif;
  --body: "Noto Sans CJK SC", "Microsoft YaHei", sans-serif;
  --mono: "IBM Plex Mono", "SFMono-Regular", Consolas, monospace;
  --ease-out: cubic-bezier(.23, 1, .32, 1);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--asphalt); color: var(--paper); font-family: var(--body); line-height: 1.72; text-rendering: optimizeLegibility; }
body::before { content: ""; position: fixed; inset: 0; z-index: -1; pointer-events: none; opacity: .17; background-image: radial-gradient(rgba(255,255,255,.15) .55px, transparent .55px); background-size: 5px 5px; }
img, video { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button, input { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
button { cursor: pointer; }
button:active, .button:active { transform: translateY(1px) scale(.98); }
:focus-visible { outline: 3px solid var(--lime); outline-offset: 4px; }
.skip-link { position: fixed; left: 1rem; top: -5rem; z-index: 9999999; padding: .7rem 1rem; color: var(--ink); background: var(--lime); transition: top 160ms var(--ease-out); }
.skip-link:focus { top: 1rem; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }
.frame { width: min(1440px, calc(100% - 3rem)); margin: 0 auto; }
.site-header { background: color-mix(in srgb, var(--asphalt) 96%, transparent); border-bottom: 1px solid var(--line-dark); }
.header-rail { min-height: 86px; padding: 0 max(1.5rem, calc((100vw - 1440px)/2)); display: grid; grid-template-columns: 330px 1fr auto; align-items: center; gap: 2rem; }
.brand-lockup { display: flex; align-items: center; gap: .9rem; min-width: 0; }
.brand-lockup img { width: 52px; height: 52px; object-fit: contain; }
.brand-lockup span { display: grid; line-height: 1.08; }
.brand-lockup strong { font-family: var(--display); font-size: 1.55rem; letter-spacing: .08em; }
.brand-lockup small { margin-top: .42rem; color: var(--muted); font-size: .7rem; letter-spacing: .1em; }
.main-nav { display: flex; justify-content: flex-end; align-items: center; gap: clamp(.8rem, 1.4vw, 1.7rem); font-size: .86rem; }
.main-nav a { color: #bfc7c3; position: relative; white-space: nowrap; transition: color 180ms var(--ease-out); }
.main-nav a::after { content: ""; position: absolute; left: 0; right: 100%; bottom: -.65rem; height: 2px; background: var(--lime); transition: right 180ms var(--ease-out); }
.main-nav a:hover { color: var(--paper); }
.main-nav a:hover::after { right: 0; }
.nav-toggle { display: none; border: 1px solid var(--line-dark); background: transparent; color: var(--paper); padding: .55rem .8rem; }
.mobile-nav { display: none; }
.search-rail { min-height: 72px; padding: 0 max(1.5rem, calc((100vw - 1440px)/2)); display: grid; grid-template-columns: minmax(300px, 720px) 1fr; gap: 3rem; align-items: center; border-top: 1px solid var(--line-dark); }
.search-demo { display: grid; grid-template-columns: 1fr auto; border-bottom: 1px solid rgba(236, 233, 223, .34); }
.search-demo input { min-width: 0; border: 0; background: transparent; color: var(--paper); padding: .85rem 0; outline: 0; }
.search-demo input::placeholder { color: var(--muted); }
.search-demo button { border: 0; background: transparent; color: var(--lime); padding: .85rem 0 .85rem 1.2rem; font-family: var(--mono); font-size: .76rem; text-transform: uppercase; }
.update-status { justify-self: end; display: flex; align-items: center; gap: .5rem; color: #bac3bf; font-size: .78rem; }
.update-status > span { width: 8px; height: 8px; background: var(--orange); box-shadow: 0 0 0 4px rgba(255, 98, 64, .12); }
.trust-rail { min-height: 34px; padding: .4rem max(1.5rem, calc((100vw - 1440px)/2)); display: grid; grid-template-columns: 1fr auto auto; gap: 2rem; align-items: center; color: #a7b1ad; background: #12231e; font-size: .68rem; }
.trust-rail a { color: var(--orange); font-weight: 700; }
.hero { min-height: 760px; position: relative; overflow: hidden; border-bottom: 1px solid var(--line-dark); }
.hero-grid { width: min(1440px, calc(100% - 3rem)); margin: 0 auto; min-height: 760px; display: grid; grid-template-columns: .88fr 1.12fr 90px; align-items: center; gap: 2.5rem; }
.hero-copy { position: relative; z-index: 3; padding: 6rem 0; }
.hero-index { display: flex; align-items: center; gap: .8rem; color: var(--orange); font-family: var(--mono); font-size: .72rem; letter-spacing: .15em; text-transform: uppercase; }
.hero-index::before { content: ""; width: 26px; height: 2px; background: var(--orange); }
.hero h1 { max-width: 780px; margin: 1.6rem 0 1.5rem; font-family: var(--display); font-size: clamp(4.2rem, 8vw, 8.8rem); font-weight: 700; line-height: .92; letter-spacing: -.06em; }
.hero h1 em { display: block; color: var(--lime); font-style: normal; }
.hero-lead { max-width: 560px; color: #c8cfcc; font-size: 1.05rem; }
.hero-actions { display: flex; flex-wrap: wrap; gap: .8rem; margin-top: 2.2rem; }
.button { display: inline-flex; align-items: center; gap: .6rem; min-height: 48px; padding: .75rem 1.1rem; border: 1px solid var(--lime); background: var(--lime); color: var(--ink); font-weight: 800; clip-path: polygon(0 0, calc(100% - 12px) 0, 100% 12px, 100% 100%, 0 100%); transition: transform 160ms var(--ease-out), background 160ms var(--ease-out); }
.button:hover { background: #e8ff8a; }
.button.secondary { background: transparent; color: var(--paper); border-color: var(--line-dark); }
.hero-visual { position: relative; height: 590px; margin-right: -9rem; }
.hero-visual img { width: 100%; height: 100%; object-fit: cover; filter: saturate(.82) contrast(1.05); }
.hero-visual::before { content: ""; position: absolute; inset: 0; z-index: 1; background: linear-gradient(90deg, var(--asphalt) 0%, transparent 38%, transparent 80%, rgba(9,17,15,.25) 100%); }
.hero-visual::after { content: "TRACK / 65EP4"; position: absolute; left: 1.3rem; bottom: 1.1rem; z-index: 2; color: var(--lime); font-family: var(--mono); font-size: .72rem; letter-spacing: .18em; }
.hero-number { align-self: end; padding-bottom: 7rem; color: var(--orange); font-family: var(--display); font-size: 5rem; border-left: 1px solid var(--orange); padding-left: 1rem; line-height: 1; }
.telemetry { border-bottom: 1px solid var(--line-dark); }
.telemetry-grid { display: grid; grid-template-columns: repeat(4, 1fr); }
.telemetry-item { min-height: 126px; padding: 1.4rem; border-right: 1px solid var(--line-dark); display: grid; align-content: space-between; }
.telemetry-item:last-child { border-right: 0; }
.telemetry-item span { color: var(--muted); font-family: var(--mono); font-size: .67rem; letter-spacing: .12em; }
.telemetry-item strong { font-family: var(--display); font-size: 1.45rem; font-weight: 600; }
.section { padding: clamp(5rem, 8vw, 8rem) 0; }
.section-paper { background: var(--paper); color: var(--ink); }
.section-ink { background: var(--asphalt); color: var(--paper); }
.section-steel { background: #cfd4cd; color: var(--ink); }
.section-head { display: grid; grid-template-columns: minmax(0, 1.2fr) minmax(260px, .55fr); gap: 4rem; align-items: end; margin-bottom: 3.5rem; }
.kicker { color: var(--orange); font-family: var(--mono); font-size: .68rem; letter-spacing: .14em; text-transform: uppercase; }
.title-xl { margin: .8rem 0 0; font-family: var(--display); font-size: clamp(2.8rem, 5.4vw, 6.2rem); line-height: 1.02; letter-spacing: -.045em; }
.title-lg { margin: .6rem 0 0; font-family: var(--display); font-size: clamp(2.25rem, 4vw, 4.7rem); line-height: 1.08; letter-spacing: -.035em; }
.title-md { margin: .5rem 0; font-family: var(--display); font-size: clamp(1.55rem, 2.3vw, 2.5rem); line-height: 1.2; }
.section-intro { color: color-mix(in srgb, currentColor 68%, transparent); max-width: 620px; }
.video-grid { display: grid; grid-template-columns: repeat(12, 1fr); gap: 2rem; }
.video-card { grid-column: span 6; border-top: 2px solid currentColor; }
.video-card:nth-child(3n+1) { grid-column: span 7; }
.video-card:nth-child(3n+2) { grid-column: span 5; margin-top: 5rem; }
.video-poster { position: relative; display: block; aspect-ratio: 16 / 10; overflow: hidden; background: var(--asphalt-2); }
.video-poster img { width: 100%; height: 100%; object-fit: cover; transition: transform 240ms var(--ease-out), filter 240ms var(--ease-out); }
.video-shade { position: absolute; inset: 0; background: linear-gradient(180deg, transparent 45%, rgba(0,0,0,.68)); }
.play-control { position: absolute; inset: 0; display: grid; place-items: center; opacity: 0; transform: translateY(8px); transition: opacity 180ms var(--ease-out), transform 180ms var(--ease-out); }
.play-control span { width: 74px; height: 74px; display: grid; place-items: center; padding-left: 4px; color: var(--ink); background: var(--lime); clip-path: polygon(0 0, 78% 0, 100% 22%, 100% 100%, 0 100%); }
.video-duration { position: absolute; right: 1rem; bottom: 1rem; z-index: 2; padding: .35rem .52rem; color: var(--paper); background: var(--asphalt); font-family: var(--mono); font-size: .7rem; }
.video-poster:hover img { transform: scale(1.025); filter: saturate(1.06); }
.video-poster:hover .play-control { opacity: 1; transform: none; }
.video-copy { padding: 1.3rem 0 2.5rem; }
.video-copy h3 { margin: .55rem 0 .7rem; font-family: var(--display); font-size: clamp(1.5rem, 2.1vw, 2.2rem); line-height: 1.18; }
.video-copy p { color: color-mix(in srgb, currentColor 70%, transparent); }
.tag-row { display: flex; flex-wrap: wrap; gap: .45rem; margin-top: 1rem; }
.tag-row span { padding: .28rem .48rem; border: 1px solid currentColor; font-size: .66rem; }
.card-meta { margin-top: 1.1rem; display: flex; justify-content: space-between; gap: 1rem; color: color-mix(in srgb, currentColor 55%, transparent); font-family: var(--mono); font-size: .66rem; }
.split-media { display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(320px, .65fr); gap: 4rem; align-items: center; }
.split-media.reverse { grid-template-columns: minmax(320px, .65fr) minmax(0, 1.15fr); }
.split-media figure { margin: 0; position: relative; }
.split-media figure img { width: 100%; min-height: 530px; object-fit: cover; }
.media-note { position: absolute; right: -2rem; bottom: 2rem; width: 240px; padding: 1.2rem; color: var(--ink); background: var(--lime); box-shadow: var(--shadow); font-family: var(--mono); font-size: .72rem; }
.feature-list { display: grid; gap: 0; margin-top: 2rem; border-top: 1px solid currentColor; }
.feature-line { display: grid; grid-template-columns: 48px 1fr; gap: 1rem; padding: 1.15rem 0; border-bottom: 1px solid currentColor; }
.feature-line > span { color: var(--orange); font-family: var(--mono); }
.feature-line strong { display: block; margin-bottom: .25rem; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.5rem; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1.3rem; }
.tech-card { min-height: 300px; padding: 1.5rem; border: 1px solid currentColor; display: flex; flex-direction: column; justify-content: space-between; clip-path: polygon(0 0, calc(100% - 18px) 0, 100% 18px, 100% 100%, 0 100%); }
.tech-card .card-number { color: var(--orange); font-family: var(--mono); font-size: .72rem; }
.tech-card h3 { font-family: var(--display); font-size: 1.7rem; margin: 4rem 0 .7rem; }
.tech-card p { color: color-mix(in srgb, currentColor 70%, transparent); }
.trust-table { width: 100%; border-collapse: collapse; }
.trust-table th, .trust-table td { padding: 1.15rem 0; border-bottom: 1px solid currentColor; text-align: left; vertical-align: top; }
.trust-table th { width: 26%; color: var(--orange); font-family: var(--mono); font-size: .73rem; }
.faq-layout { display: grid; grid-template-columns: .55fr 1fr; gap: 5rem; align-items: start; }
.faq-list { border-top: 2px solid currentColor; }
.faq-item { border-bottom: 1px solid currentColor; }
.faq-item summary { list-style: none; cursor: pointer; padding: 1.35rem 2.3rem 1.35rem 0; position: relative; font-weight: 800; }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: "+"; position: absolute; right: 0; color: var(--orange); font-family: var(--mono); font-size: 1.4rem; }
.faq-item[open] summary::after { content: "−"; }
.faq-item p { margin: 0; padding: 0 3rem 1.5rem 0; color: color-mix(in srgb, currentColor 68%, transparent); }
.empty-state { padding: 2rem; border: 1px solid currentColor; background: color-mix(in srgb, currentColor 6%, transparent); }
.empty-state strong { display: block; font-family: var(--display); font-size: 1.8rem; }
.detail-hero { padding: 5.5rem 0 4rem; border-bottom: 1px solid var(--line-dark); }
.breadcrumb { color: var(--muted); font-size: .76rem; margin-bottom: 2rem; }
.breadcrumb a { color: var(--lime); }
.detail-grid { display: grid; grid-template-columns: 1.1fr .55fr; gap: 5rem; align-items: end; }
.detail-meta { border-top: 2px solid var(--orange); }
.detail-meta > div { display: grid; grid-template-columns: 110px 1fr; gap: 1rem; padding: .9rem 0; border-bottom: 1px solid var(--line-dark); }
.detail-meta span { color: var(--muted); font-family: var(--mono); font-size: .68rem; }
.player-shell { background: #000; border: 1px solid var(--line-dark); }
.player-shell video { width: 100%; aspect-ratio: 16/9; background: #000; object-fit: cover; }
.article-layout { display: grid; grid-template-columns: minmax(0, 1fr) 300px; gap: 5rem; align-items: start; }
.article-body { font-size: 1.05rem; }
.article-body h2, .article-body h3 { font-family: var(--display); line-height: 1.2; }
.article-body h2 { font-size: 2.3rem; margin: 3.5rem 0 1rem; }
.article-body h3 { font-size: 1.55rem; margin: 2.3rem 0 .8rem; }
.article-body p { color: #c4ccc8; }
.article-aside { position: sticky; top: 1.5rem; border-top: 2px solid var(--lime); }
.article-aside > div { padding: 1rem 0; border-bottom: 1px solid var(--line-dark); }
.article-aside span { display: block; color: var(--muted); font-family: var(--mono); font-size: .68rem; }
.article-aside strong { display: block; margin-top: .35rem; }
.site-footer { padding: 5rem max(1.5rem, calc((100vw - 1440px)/2)) 0; color: var(--paper); background: #050a09; border-top: 1px solid var(--line-dark); }
.footer-grid { display: grid; grid-template-columns: 1.15fr .65fr .9fr .9fr; gap: 3rem; }
.footer-brand { display: flex; align-items: flex-start; gap: 1rem; }
.footer-brand img { width: 68px; height: 68px; object-fit: contain; }
.footer-brand strong { font-family: var(--display); font-size: 2rem; }
.footer-brand p { color: var(--muted); margin: .3rem 0; }
.footer-links, .footer-contact { display: grid; align-content: start; gap: .45rem; }
.footer-links h2, .footer-contact h2 { margin: 0 0 .7rem; font-family: var(--mono); font-size: .78rem; color: var(--lime); }
.footer-links a, .footer-contact p { margin: 0; color: #aeb8b3; font-size: .82rem; }
.footer-contact small { margin-top: .6rem; color: #68736e; }
.qr-pair { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
.qr-pair figure { margin: 0; }
.qr-pair img { width: 100%; max-width: 132px; background: var(--paper); }
.qr-pair figcaption { color: var(--muted); font-size: .68rem; margin-top: .5rem; }
.share-rail { display: flex; align-items: center; gap: .6rem; margin-top: 3rem; padding: 1.25rem 0; border-top: 1px solid var(--line-dark); border-bottom: 1px solid var(--line-dark); }
.share-rail span { color: var(--muted); font-size: .75rem; margin-right: .5rem; }
.share-rail button { border: 1px solid var(--line-dark); color: var(--paper); background: transparent; padding: .45rem .7rem; }
.footer-bottom { display: flex; justify-content: space-between; gap: 1rem; padding: 1.2rem 0; color: #707a76; font-family: var(--mono); font-size: .68rem; }
.toast { position: fixed; left: 50%; bottom: 1.5rem; z-index: 9999998; max-width: min(90vw, 560px); transform: translate(-50%, 20px); opacity: 0; pointer-events: none; padding: .85rem 1rem; color: var(--ink); background: var(--lime); box-shadow: var(--shadow); transition: opacity 180ms var(--ease-out), transform 180ms var(--ease-out); }
.toast.is-visible { opacity: 1; transform: translate(-50%, 0); }
@media (max-width: 1120px) {
  .header-rail { grid-template-columns: 1fr auto; }
  .main-nav { display: none; }
  .nav-toggle { display: block; }
  .mobile-nav.is-open { display: grid; padding: 0 1.5rem 1rem; }
  .mobile-nav a { padding: .75rem 0; border-bottom: 1px solid var(--line-dark); }
  .hero-grid { grid-template-columns: .85fr 1.15fr 70px; }
  .hero-visual { margin-right: -4rem; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 820px) {
  .frame, .hero-grid { width: min(100% - 2rem, 720px); }
  .search-rail { grid-template-columns: 1fr; gap: .8rem; padding-top: .7rem; padding-bottom: .7rem; }
  .update-status { justify-self: start; }
  .trust-rail { grid-template-columns: 1fr auto; gap: 1rem; }
  .trust-rail a:last-child { display: none; }
  .hero { min-height: auto; }
  .hero-grid { min-height: auto; grid-template-columns: 1fr; gap: 0; padding-bottom: 4rem; }
  .hero-copy { padding: 4.5rem 0 2rem; }
  .hero h1 { font-size: clamp(3.7rem, 17vw, 7rem); }
  .hero-visual { height: 420px; margin: 0; }
  .hero-number { display: none; }
  .telemetry-grid { grid-template-columns: 1fr 1fr; }
  .telemetry-item:nth-child(2) { border-right: 0; }
  .section-head, .split-media, .split-media.reverse, .faq-layout, .detail-grid, .article-layout { grid-template-columns: 1fr; gap: 2.5rem; }
  .video-card, .video-card:nth-child(3n+1), .video-card:nth-child(3n+2) { grid-column: span 12; margin-top: 0; }
  .grid-4 { grid-template-columns: 1fr 1fr; }
  .grid-3 { grid-template-columns: 1fr; }
  .split-media figure img { min-height: 380px; }
  .media-note { right: .8rem; bottom: .8rem; }
  .article-aside { position: static; }
}
@media (max-width: 560px) {
  .header-rail { min-height: 72px; padding: 0 1rem; }
  .brand-lockup img { width: 44px; height: 44px; }
  .brand-lockup strong { font-size: 1.3rem; }
  .brand-lockup small { font-size: .62rem; }
  .search-rail, .trust-rail { padding-left: 1rem; padding-right: 1rem; }
  .trust-rail { grid-template-columns: 1fr; }
  .trust-rail a { display: none; }
  .hero h1 { font-size: clamp(3.2rem, 18vw, 5.4rem); }
  .hero-visual { height: 300px; }
  .hero-actions { display: grid; }
  .button { justify-content: center; }
  .telemetry-grid, .grid-4, .footer-grid, .qr-pair { grid-template-columns: 1fr; }
  .telemetry-item { border-right: 0; }
  .section { padding: 4.5rem 0; }
  .title-xl { font-size: 2.75rem; }
  .card-meta, .footer-bottom { flex-direction: column; }
  .share-rail { flex-wrap: wrap; }
  .qr-pair img { max-width: 116px; }
}
@media (prefers-reduced-motion: no-preference) {
  .hero-copy > * { animation: rail-in 620ms var(--ease-out) both; }
  .hero-copy > *:nth-child(2) { animation-delay: 50ms; }
  .hero-copy > *:nth-child(3) { animation-delay: 100ms; }
  .hero-copy > *:nth-child(4) { animation-delay: 150ms; }
  @keyframes rail-in { from { opacity: 0; transform: translateX(-8px); } to { opacity: 1; transform: none; } }
}