/* ai-frontier-v1 — dark theme with yellow accent.
 *
 * This stylesheet is self-contained on purpose: the templates that share
 * style.css and the mechanical business.css must not gain a single byte, so
 * every rule the dark template needs lives here.
 *
 * Palette is taken from the reference design: near-black and charcoal bands,
 * hairline borders instead of shadows, one saturated yellow reserved for
 * buttons, geometric marks and small accents, near-white headings and grey
 * body copy.
 */

.ai-frontier-v1 {
  --ai-black: #050505;
  --ai-ink: #080808;
  --ai-panel: #0c0c0c;
  --ai-card: #131313;
  --ai-card-2: #171717;
  --ai-line: rgba(255, 255, 255, .09);
  --ai-line-strong: rgba(255, 255, 255, .16);
  --ai-accent: #ffd500;
  --ai-accent-dim: rgba(255, 213, 0, .14);
  --ai-heading: #f4f4f4;
  --ai-body: #8d8d8d;
  --ai-muted: #6e6e6e;
  background: var(--ai-black);
  color: var(--ai-body);
  font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 15px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.ai-frontier-v1 *, .ai-frontier-v1 *::before, .ai-frontier-v1 *::after { box-sizing: border-box; }
.ai-frontier-v1 img { max-width: 100%; display: block; }
.ai-frontier-v1 h1, .ai-frontier-v1 h2, .ai-frontier-v1 h3, .ai-frontier-v1 h4 {
  color: var(--ai-heading);
  font-weight: 600;
  letter-spacing: -.01em;
  margin: 0;
}
.ai-frontier-v1 p { margin: 0; }
.ai-frontier-v1 ul, .ai-frontier-v1 ol { list-style: none; margin: 0; padding: 0; }
.ai-frontier-v1 a { color: inherit; text-decoration: none; }
.ai-frontier-v1 strong { font-weight: 600; }

.ai-container { width: 100%; max-width: 1400px; margin: 0 auto; padding: 0 40px; }
.ai-sr { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0; }

/* Marks are drawn in code; they inherit the accent colour and never shrink. */
.ai-mark { width: 34px; height: 34px; flex: none; fill: var(--ai-accent); }
.ai-frontier-v1 .ai-mark [fill] { fill: var(--ai-card); }

.ai-preview { background: var(--ai-accent); color: #000; font-size: 13px; font-weight: 600; padding: 7px 20px; text-align: center; letter-spacing: .04em; }

/* ---------------------------------------------------------- announcement bar */
.ai-announce { background: var(--ai-ink); border-bottom: 1px solid var(--ai-line); }
.ai-announce p { text-align: center; font-size: 12px; color: var(--ai-muted); letter-spacing: .06em; line-height: 2.1; }
.ai-announce a { transition: color .18s ease; }
.ai-announce a:hover { color: var(--ai-heading); }
.ai-announce-arrow { color: var(--ai-accent); font-weight: 700; }

/* ---------------------------------------------------------- header */
.ai-header { background: #000; border-bottom: 1px solid var(--ai-line); position: sticky; top: 0; z-index: 40; }
.ai-nav { display: flex; align-items: center; gap: 28px; min-height: 66px; }
.ai-brand { display: inline-flex; align-items: center; gap: 11px; color: var(--ai-heading); font-size: 17px; font-weight: 600; letter-spacing: .01em; }
.ai-brand .ai-mark { width: 27px; height: 27px; }
.ai-brand-logo { max-height: 34px; width: auto; }
.ai-nav-links { display: flex; align-items: center; gap: 4px; margin: 0 auto; }
.ai-nav-links a { padding: 7px 15px; font-size: 14px; color: var(--ai-body); border: 1px solid transparent; border-radius: 4px; transition: color .18s ease, border-color .18s ease; white-space: nowrap; }
.ai-nav-links a:hover { color: var(--ai-heading); }
.ai-nav-links a[aria-current="page"] { color: var(--ai-heading); border-color: var(--ai-line-strong); background: rgba(255, 255, 255, .04); }

/* ---------------------------------------------------------- buttons */
.ai-btn { display: inline-flex; align-items: center; justify-content: center; gap: 7px; padding: 11px 20px; font-size: 13.5px; font-weight: 500; border-radius: 5px; border: 1px solid transparent; transition: background .18s ease, border-color .18s ease, color .18s ease; white-space: nowrap; }
.ai-btn-solid { background: var(--ai-accent); color: #000; font-weight: 600; }
.ai-btn-solid:hover { background: #ffe14d; }
.ai-btn-ghost { border-color: var(--ai-line-strong); color: var(--ai-heading); }
.ai-btn-ghost:hover { border-color: rgba(255, 255, 255, .34); background: rgba(255, 255, 255, .04); }
.ai-textlink { display: inline-flex; align-items: center; gap: 6px; font-size: 13.5px; color: var(--ai-accent); transition: gap .18s ease; }
.ai-textlink:hover { gap: 10px; }
.ai-arrow { width: 40px; height: 40px; border-radius: 50%; background: var(--ai-accent); color: #000; display: inline-flex; align-items: center; justify-content: center; font-size: 15px; font-weight: 700; flex: none; transition: transform .2s ease, background .18s ease; }
.ai-arrow:hover { transform: translate(2px, -2px); background: #ffe14d; }

.ai-eyebrow { color: var(--ai-muted); font-size: 13px; letter-spacing: .04em; margin-bottom: 18px; }
.ai-eyebrow-pill { display: inline-block; background: rgba(255, 255, 255, .07); color: #9a9a9a; padding: 5px 12px; border-radius: 3px; font-size: 12.5px; margin-bottom: 22px; }
.ai-muted { color: var(--ai-muted); font-size: 14px; margin-top: 18px; }
.ai-tag { display: inline-block; font-size: 12px; color: var(--ai-muted); border: 1px solid var(--ai-line); border-radius: 999px; padding: 3px 12px; align-self: flex-start; transition: color .18s ease, border-color .18s ease; }
a.ai-tag:hover { color: var(--ai-accent); border-color: rgba(255, 213, 0, .4); }

.ai-section-head { display: flex; align-items: flex-end; justify-content: space-between; gap: 32px; margin-bottom: 46px; }
.ai-section-head h2 { font-size: clamp(26px, 3vw, 38px); line-height: 1.25; font-weight: 500; }

/* ---------------------------------------------------------- hero */
.ai-hero { background: var(--ai-ink); border-bottom: 1px solid var(--ai-line); }
.ai-hero-grid { display: grid; grid-template-columns: minmax(0, .95fr) minmax(0, 1.05fr); gap: 68px; padding: 84px 0 88px; align-items: start; }
.ai-hero-copy h1 { font-size: clamp(32px, 3.9vw, 52px); line-height: 1.16; font-weight: 500; letter-spacing: -.02em; }
.ai-hero-desc { margin-top: 24px; color: var(--ai-body); font-size: 15px; max-width: 46ch; }

.ai-stats { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); border-top: 1px solid var(--ai-line); margin-top: 52px; }
.ai-stats li { padding: 26px 22px 0 0; display: flex; flex-direction: column; gap: 4px; border-right: 1px solid var(--ai-line); }
.ai-stats li:last-child { border-right: 0; }
.ai-stats li:not(:first-child) { padding-left: 22px; }
.ai-stats strong { color: var(--ai-heading); font-size: 30px; line-height: 1.2; font-weight: 500; letter-spacing: -.02em; }
.ai-stats span { font-size: 13.5px; color: #b9b9b9; }
.ai-stats em { font-style: normal; font-size: 12px; color: var(--ai-muted); }

.ai-hero-art { position: relative; min-height: 540px; display: flex; align-items: flex-end; overflow: hidden; }
.ai-burst { position: absolute; inset: 0; width: 100%; height: 100%; }
.ai-hero-card { position: relative; width: min(430px, 92%); background: rgba(10, 10, 10, .92); border: 1px solid var(--ai-line); border-radius: 6px; overflow: hidden; backdrop-filter: blur(3px); transition: border-color .2s ease, transform .2s ease; }
.ai-hero-card:hover { border-color: rgba(255, 213, 0, .38); transform: translateY(-3px); }
.ai-hero-card > img { width: 100%; height: 190px; object-fit: cover; }
.ai-hero-card-body { padding: 22px 24px 24px; display: flex; flex-direction: column; gap: 10px; align-items: flex-start; }
.ai-hero-card-body h2 { font-size: 18px; font-weight: 600; line-height: 1.45; }
.ai-hero-card-body p { font-size: 13.5px; color: var(--ai-body); }

/* ---------------------------------------------------------- three entrances */
.ai-entries { background: #000; border-bottom: 1px solid var(--ai-line); }
.ai-entries ul { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); }
.ai-entries li { padding: 46px 40px 50px; border-right: 1px solid var(--ai-line); display: flex; flex-direction: column; gap: 20px; }
.ai-entries li:first-child { padding-left: 0; }
.ai-entries li:last-child { border-right: 0; padding-right: 0; }
.ai-entry-head { display: flex; align-items: center; gap: 15px; }
.ai-entry-head h2 { font-size: 19px; font-weight: 600; }
.ai-entry-sub { font-size: 12.5px; color: var(--ai-muted); }
.ai-entry-head .ai-arrow { margin-left: auto; }
.ai-entry-desc { font-size: 13.5px; color: var(--ai-body); }

/* ---------------------------------------------------------- feature blocks */
.ai-features { background: var(--ai-ink); border-bottom: 1px solid var(--ai-line); padding: 84px 0 0; }
.ai-feature-row { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.25fr); border: 1px solid var(--ai-line); border-bottom: 0; }
.ai-feature-row:last-child { border-bottom: 1px solid var(--ai-line); }
.ai-feature-lead { background: var(--ai-panel); padding: 54px 44px; display: flex; flex-direction: column; justify-content: center; gap: 20px; border-right: 1px solid var(--ai-line); }
.ai-feature-lead .ai-mark { width: 46px; height: 46px; }
.ai-feature-lead h3 { font-size: 26px; font-weight: 500; }
.ai-feature-lead p { font-size: 13.5px; color: var(--ai-body); max-width: 34ch; }
.ai-feature-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px; padding: 30px; }
.ai-feature-grid li { background: var(--ai-card); border: 1px solid var(--ai-line); border-radius: 5px; padding: 24px 26px 26px; display: flex; flex-direction: column; gap: 9px; align-items: flex-start; }
.ai-feature-grid h4 { font-size: 16px; font-weight: 600; }
.ai-feature-grid p { font-size: 13px; color: var(--ai-body); }
.ai-feature-grid .ai-textlink { margin-top: 4px; }

/* ---------------------------------------------------------- articles */
.ai-articles { background: #000; border-bottom: 1px solid var(--ai-line); padding: 88px 0 92px; }
.ai-tabstrip { display: flex; flex-wrap: wrap; gap: 12px; padding: 22px 0; margin: 34px 0 0; border-top: 1px solid var(--ai-line); border-bottom: 1px solid var(--ai-line); }
.ai-tab { padding: 10px 24px; border: 1px solid var(--ai-line); border-radius: 4px; font-size: 13.5px; color: var(--ai-body); transition: color .18s ease, border-color .18s ease, background .18s ease; }
.ai-tab:hover { color: var(--ai-heading); border-color: var(--ai-line-strong); }
.ai-tab.is-active { color: #000; background: var(--ai-accent); border-color: var(--ai-accent); font-weight: 600; }

.ai-rows { margin-top: 8px; }
.ai-row { display: flex; align-items: center; gap: 32px; padding: 34px 0; border-bottom: 1px solid var(--ai-line); }
.ai-row:last-child { border-bottom: 0; }
.ai-row-serial { width: 46px; height: 46px; flex: none; display: inline-flex; align-items: center; justify-content: center; border: 1px solid rgba(255, 213, 0, .34); border-radius: 4px; color: var(--ai-accent); font-size: 14px; font-weight: 600; letter-spacing: .04em; }
.ai-row-body { display: flex; flex-direction: column; gap: 9px; align-items: flex-start; min-width: 0; }
.ai-row-body h3 { font-size: 21px; font-weight: 600; line-height: 1.4; }
.ai-row-body h3 a:hover { color: var(--ai-accent); }
.ai-row-body p { font-size: 13.5px; color: var(--ai-body); max-width: 68ch; }
.ai-row-cta { margin-left: auto; flex: none; }

/* ---------------------------------------------------------- resources */
.ai-resources { background: var(--ai-ink); border-bottom: 1px solid var(--ai-line); padding: 88px 0 92px; }
/* Five channels each contribute one card, so the grid fits the width
   instead of leaving an orphan in a fixed four-column track. */
.ai-resource-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(232px, 1fr)); gap: 22px; }
.ai-resource-grid li { display: flex; flex-direction: column; gap: 11px; align-items: flex-start; }
.ai-resource-photo { display: block; width: 100%; aspect-ratio: 16 / 10; background: var(--ai-card); border: 1px solid var(--ai-line); border-radius: 5px; overflow: hidden; }
.ai-resource-photo img { width: 100%; height: 100%; object-fit: cover; transition: transform .35s ease; }
.ai-resource-grid li:hover .ai-resource-photo img { transform: scale(1.04); }
.ai-resource-grid h3 { font-size: 16.5px; font-weight: 600; line-height: 1.45; }
.ai-resource-grid h3 a:hover { color: var(--ai-accent); }
.ai-resource-grid p { font-size: 13px; color: var(--ai-body); }

/* ---------------------------------------------------------- about */
.ai-about { background: #000; padding: 84px 0 88px; }
.ai-about-text { max-width: 78ch; display: flex; flex-direction: column; gap: 16px; }
.ai-about-text p { font-size: 15px; color: var(--ai-body); }

/* ---------------------------------------------------------- archive & article */
.ai-page { padding: 62px 0 92px; }
.ai-breadcrumb { display: flex; align-items: center; gap: 9px; flex-wrap: wrap; font-size: 12.5px; color: var(--ai-muted); padding-bottom: 34px; border-bottom: 1px solid var(--ai-line); }
.ai-breadcrumb a:hover { color: var(--ai-heading); }
.ai-page-head { padding: 46px 0 42px; }
.ai-page-head h1 { font-size: clamp(28px, 3.4vw, 44px); font-weight: 500; line-height: 1.2; }
.ai-page-head p { margin-top: 18px; color: var(--ai-body); max-width: 62ch; }

.ai-index { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 22px; padding: 44px 0 10px; }
.ai-index li { border: 1px solid var(--ai-line); border-radius: 5px; overflow: hidden; background: var(--ai-card); transition: border-color .2s ease; }
.ai-index li:hover { border-color: rgba(255, 213, 0, .32); }
.ai-index a { display: flex; flex-direction: column; height: 100%; }
.ai-index-photo { display: block; width: 100%; aspect-ratio: 16 / 9; background: var(--ai-card-2); }
.ai-index-photo img { width: 100%; height: 100%; object-fit: cover; }
.ai-index-body { padding: 22px 24px 24px; display: flex; flex-direction: column; gap: 9px; align-items: flex-start; }
.ai-index-title { color: var(--ai-heading); font-size: 17px; font-weight: 600; line-height: 1.45; }
.ai-index-summary { color: var(--ai-body); font-size: 13.5px; }

.ai-article { max-width: 1000px; padding: 46px 0 0; }
.ai-article h1 { font-size: clamp(28px, 3.6vw, 44px); font-weight: 500; line-height: 1.2; }
.ai-article-summary { margin-top: 20px; font-size: 16px; color: var(--ai-body); max-width: 70ch; }
.ai-figure { margin: 42px 0 0; }
.ai-figure img { width: 100%; border-radius: 6px; border: 1px solid var(--ai-line); }
.ai-figure figcaption { margin-top: 12px; font-size: 12.5px; color: var(--ai-muted); }
.ai-prose { margin-top: 44px; max-width: 74ch; }
.ai-prose p { font-size: 15.5px; line-height: 1.9; color: #b4b4b4; margin-bottom: 20px; }
.ai-prose h2 { font-size: 21px; font-weight: 600; margin: 42px 0 18px; padding-left: 14px; border-left: 2px solid var(--ai-accent); }
.ai-chips { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 48px; padding-top: 30px; border-top: 1px solid var(--ai-line); }
.ai-chip { border: 1px solid var(--ai-line); border-radius: 999px; padding: 7px 17px; font-size: 13px; color: var(--ai-body); transition: color .18s ease, border-color .18s ease; }
.ai-chip:hover { color: var(--ai-heading); border-color: var(--ai-line-strong); }

.ai-related { margin-top: 64px; padding-top: 40px; border-top: 1px solid var(--ai-line); }
.ai-related h2 { font-size: 22px; font-weight: 500; }
.ai-related ul { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px; margin-top: 26px; }
.ai-related li { border: 1px solid var(--ai-line); border-radius: 5px; padding: 20px 22px; background: var(--ai-card); }
.ai-related a { color: var(--ai-heading); font-size: 15.5px; font-weight: 600; line-height: 1.45; }
.ai-related a:hover { color: var(--ai-accent); }
.ai-related p { margin-top: 8px; font-size: 13px; color: var(--ai-body); }
.ai-empty { color: var(--ai-muted); padding: 46px 0; }

/* ---------------------------------------------------------- footer */
.ai-footer { background: #000; border-top: 1px solid var(--ai-line); padding: 66px 0 34px; }
.ai-footer-grid { display: grid; grid-template-columns: minmax(0, 1.35fr) repeat(2, minmax(0, .65fr)) minmax(0, 1.4fr); gap: 40px; }
.ai-footer-brand { display: flex; flex-direction: column; gap: 14px; align-items: flex-start; }
.ai-footer-brand .ai-mark { width: 30px; height: 30px; }
.ai-footer-brand strong { color: var(--ai-heading); font-size: 16px; font-weight: 600; }
.ai-footer-brand p { font-size: 13px; color: var(--ai-muted); max-width: 34ch; }
.ai-footer-col h2 { font-size: 13px; font-weight: 600; letter-spacing: .08em; color: #b9b9b9; text-transform: uppercase; margin-bottom: 18px; }
.ai-footer-col li { margin-bottom: 9px; font-size: 13.5px; }
.ai-footer-col a:hover { color: var(--ai-accent); }
.ai-footer-col p { font-size: 12.5px; color: var(--ai-muted); margin-bottom: 14px; }
.ai-footer-links ul { display: flex; flex-wrap: wrap; gap: 7px 16px; }
.ai-footer-links li { font-size: 12.5px; margin: 0; }
.ai-link-placeholder { color: var(--ai-muted); font-size: 12.5px; }
.ai-footer-bottom { display: flex; align-items: center; justify-content: space-between; gap: 20px; flex-wrap: wrap; margin-top: 54px; padding-top: 26px; border-top: 1px solid var(--ai-line); font-size: 12.5px; color: var(--ai-muted); }
.ai-footer-bottom a:hover { color: var(--ai-accent); }

/* ---------------------------------------------------------- responsive */
@media (max-width: 1180px) {
  .ai-hero-grid { grid-template-columns: minmax(0, 1fr); gap: 48px; }
  .ai-hero-art { min-height: 420px; }
  .ai-resource-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .ai-feature-row { grid-template-columns: minmax(0, 1fr); }
  .ai-feature-lead { border-right: 0; border-bottom: 1px solid var(--ai-line); }
  .ai-footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .ai-nav-links { flex-wrap: wrap; justify-content: center; }
}

@media (max-width: 860px) {
  .ai-container { padding: 0 24px; }
  .ai-nav { flex-wrap: wrap; padding: 14px 0; gap: 14px; }
  .ai-nav-links { order: 3; width: 100%; margin: 0; justify-content: flex-start; overflow-x: auto; flex-wrap: nowrap; padding-bottom: 4px; scrollbar-width: none; }
  .ai-nav-links::-webkit-scrollbar { display: none; }
  .ai-nav > .ai-btn { margin-left: auto; }
  .ai-entries ul { grid-template-columns: minmax(0, 1fr); }
  .ai-entries li, .ai-entries li:first-child, .ai-entries li:last-child { border-right: 0; border-bottom: 1px solid var(--ai-line); padding: 34px 0; }
  .ai-entries li:last-child { border-bottom: 0; }
  .ai-section-head { flex-direction: column; align-items: flex-start; gap: 20px; }
  .ai-index, .ai-related ul { grid-template-columns: minmax(0, 1fr); }
  .ai-feature-grid { grid-template-columns: minmax(0, 1fr); padding: 20px; }
  .ai-feature-lead { padding: 38px 28px; }
}

@media (max-width: 560px) {
  .ai-container { padding: 0 18px; }
  .ai-announce p { font-size: 11px; letter-spacing: .03em; }
  .ai-brand { font-size: 15px; gap: 9px; }
  .ai-brand .ai-mark { width: 23px; height: 23px; }
  .ai-nav > .ai-btn { padding: 9px 14px; font-size: 12.5px; }
  .ai-hero-grid { padding: 52px 0 60px; gap: 40px; }
  .ai-hero-art { min-height: 320px; }
  .ai-hero-card > img { height: 150px; }
  .ai-stats { grid-template-columns: minmax(0, 1fr); gap: 0; }
  .ai-stats li, .ai-stats li:not(:first-child) { border-right: 0; border-bottom: 1px solid var(--ai-line); padding: 20px 0; }
  .ai-stats li:last-child { border-bottom: 0; }
  .ai-stats strong { font-size: 26px; }
  .ai-feature-lead h3 { font-size: 22px; }
  .ai-row { flex-direction: column; align-items: flex-start; gap: 16px; padding: 26px 0; }
  .ai-row-serial { width: 38px; height: 38px; font-size: 13px; }
  .ai-row-body h3 { font-size: 18px; }
  .ai-row-cta { margin-left: 0; }
  .ai-resource-grid { grid-template-columns: minmax(0, 1fr); }
  .ai-footer-grid { grid-template-columns: minmax(0, 1fr); gap: 32px; }
  .ai-page { padding: 40px 0 70px; }
  .ai-prose p { font-size: 15px; }
}