/* ==========================================================================
   汇赢国际官网 — style.css
   跨境电商AI / 智能选品 / Listing优化 / 海外市场分析
   ========================================================================== */

/* -------------------- 1. Reset -------------------- */
*, *::before, *::after { box-sizing: border-box; }
html, body, h1, h2, h3, h4, p, ul, ol, li, figure, figcaption { margin: 0; padding: 0; }
img, svg { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; }
button, input, select, textarea { font: inherit; color: inherit; }
button { cursor: pointer; background: none; border: none; }
table { border-collapse: collapse; width: 100%; }

/* -------------------- 2. Design tokens -------------------- */
:root {
  --c-warm: #FAF7F1;
  --c-warm-2: #F3EEE4;
  --c-navy: #13294B;
  --c-navy-2: #1D3A66;
  --c-cyan: #0EA5B7;
  --c-cyan-soft: #E3F4F6;
  --c-graphite: #4B4F58;
  --c-green: #2E9E63;
  --c-green-soft: #E6F5EC;
  --c-orange: #E2822E;
  --c-orange-soft: #FCEEE0;
  --c-line: #D8D2C4;
  --c-white: #FFFFFF;
  --c-text: #202634;
  --c-text-soft: #5B6270;

  --font-base: "PingFang SC", "Microsoft YaHei", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --container: 1180px;
  --radius-s: 8px;
  --radius-m: 14px;
  --radius-l: 22px;
  --shadow-card: 0 6px 24px rgba(19, 41, 75, 0.08);
  --shadow-soft: 0 2px 10px rgba(19, 41, 75, 0.06);
}

/* -------------------- 3. Base -------------------- */
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-base);
  background: var(--c-warm);
  color: var(--c-text);
  line-height: 1.75;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}
h1, h2, h3, h4 { font-weight: 700; color: var(--c-navy); line-height: 1.4; }
h1 { font-size: 2rem; }
h2 { font-size: 1.6rem; }
h3 { font-size: 1.25rem; }
h4 { font-size: 1.05rem; }
p { color: var(--c-text); }
p + p { margin-top: 0.9em; }

.section { padding: 64px 0; }
.section--tight { padding: 40px 0; }
.section--alt { background: var(--c-warm-2); }
.section-head { max-width: 760px; margin: 0 0 36px; }
.section-eyebrow {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--c-cyan);
  letter-spacing: 0.06em;
  background: var(--c-cyan-soft);
  padding: 4px 12px;
  border-radius: 999px;
  margin-bottom: 12px;
}
.section-desc { color: var(--c-text-soft); margin-top: 10px; font-size: 0.98rem; }

.skip-link {
  position: absolute; left: -999px; top: 0; background: var(--c-navy); color: #fff;
  padding: 10px 16px; z-index: 999; border-radius: 0 0 8px 0;
}
.skip-link:focus { left: 0; }

/* -------------------- 4. Header & Nav -------------------- */
.site-header {
  position: sticky; top: 0; z-index: 200;
  background: rgba(250, 247, 241, 0.94);
  backdrop-filter: saturate(160%) blur(8px);
  border-bottom: 1px solid var(--c-line);
}
.site-header__bar {
  display: flex; align-items: center; justify-content: space-between;
  height: 72px;
}
.brand { display: flex; align-items: center; gap: 10px; }
.brand__mark { width: 36px; height: 36px; flex: none; }
.brand__name { font-weight: 700; color: var(--c-navy); font-size: 1.08rem; line-height: 1.2; }
.brand__sub { display: block; font-size: 0.68rem; color: var(--c-text-soft); font-weight: 400; letter-spacing: 0.03em; }

.main-nav { display: flex; align-items: center; gap: 4px; }
.main-nav a {
  display: inline-block; padding: 10px 16px; border-radius: 999px;
  font-size: 0.95rem; font-weight: 500; color: var(--c-navy);
  transition: background 0.15s ease, color 0.15s ease;
}
.main-nav a:hover, .main-nav a[aria-current="page"] {
  background: var(--c-navy); color: var(--c-white);
}

.nav-toggle {
  display: none; width: 42px; height: 42px; border-radius: 10px;
  align-items: center; justify-content: center; flex: none;
  border: 1px solid var(--c-line);
}
.nav-toggle span, .nav-toggle::before, .nav-toggle::after {
  content: ""; display: block; width: 20px; height: 2px; background: var(--c-navy);
  position: relative;
}
.nav-toggle::before { transform: translateY(-6px); }
.nav-toggle::after { transform: translateY(4px); }
.nav-toggle span { position: absolute; }

/* -------------------- 5. Buttons / tags -------------------- */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 22px; border-radius: 999px; font-weight: 600; font-size: 0.95rem;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}
.btn--primary { background: var(--c-navy); color: var(--c-white); }
.btn--primary:hover { transform: translateY(-1px); box-shadow: var(--shadow-card); }
.btn--ghost { background: var(--c-white); color: var(--c-navy); border: 1px solid var(--c-line); }
.btn--ghost:hover { border-color: var(--c-navy); }
.btn--cyan { background: var(--c-cyan); color: var(--c-white); }
.btn-row { display: flex; gap: 14px; flex-wrap: wrap; }

.tag {
  display: inline-block; font-size: 0.76rem; font-weight: 600;
  padding: 3px 11px; border-radius: 999px; background: var(--c-warm-2); color: var(--c-graphite);
}
.tag--cyan { background: var(--c-cyan-soft); color: #0B7C89; }
.tag--green { background: var(--c-green-soft); color: #1F7A4B; }
.tag--orange { background: var(--c-orange-soft); color: #A85A1B; }
.tag--navy { background: rgba(19,41,75,0.08); color: var(--c-navy); }

.link-arrow { color: var(--c-cyan); font-weight: 600; font-size: 0.92rem; white-space: nowrap; }
.link-arrow::after { content: "→"; margin-left: 4px; transition: margin 0.15s ease; display: inline-block; }
.link-arrow:hover::after { margin-left: 8px; }

/* -------------------- 6. Hero -------------------- */
.hero {
  padding: 56px 0 48px;
  background:
    radial-gradient(600px 300px at 85% -10%, rgba(14,165,183,0.10), transparent 60%),
    var(--c-warm);
}
.hero__grid { display: grid; grid-template-columns: 1.05fr 0.95fr; gap: 48px; align-items: center; }
.breadcrumb { font-size: 0.82rem; color: var(--c-text-soft); margin-bottom: 18px; }
.breadcrumb a { color: var(--c-text-soft); }
.breadcrumb a:hover { color: var(--c-cyan); }
.hero h1 { font-size: 2.3rem; margin-bottom: 18px; }
.hero__lede { font-size: 1.04rem; color: var(--c-text-soft); }
.hero__figure { border-radius: var(--radius-l); overflow: hidden; background: var(--c-white); box-shadow: var(--shadow-card); padding: 18px; }
.hero__tagrow { display: flex; gap: 10px; flex-wrap: wrap; margin: 22px 0; }

/* -------------------- 7. Data chain strip -------------------- */
.chain-strip {
  display: flex; flex-wrap: wrap; gap: 8px; align-items: center;
  padding: 18px; background: var(--c-white); border: 1px solid var(--c-line); border-radius: var(--radius-m);
}
.chain-strip__node {
  font-size: 0.82rem; font-weight: 600; color: var(--c-navy);
  background: var(--c-warm-2); padding: 7px 12px; border-radius: 999px;
}
.chain-strip__arrow { color: var(--c-line); font-weight: 700; }

/* -------------------- 8. Figures -------------------- */
figure.diagram {
  background: var(--c-white); border: 1px solid var(--c-line); border-radius: var(--radius-m);
  padding: 20px; margin: 0;
}
figure.diagram img { border-radius: 6px; }
figure.diagram figcaption {
  margin-top: 12px; font-size: 0.86rem; color: var(--c-text-soft); text-align: center;
}
.figure-2col { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }

/* -------------------- 9. Flagship articles (homepage) -------------------- */
.flagship {
  background: var(--c-white); border: 1px solid var(--c-line); border-radius: var(--radius-l);
  padding: 34px; margin-bottom: 30px; box-shadow: var(--shadow-soft);
  scroll-margin-top: 90px;
}
.flagship__meta { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; font-size: 0.82rem; color: var(--c-text-soft); margin-bottom: 14px; }
.flagship__index {
  display: inline-flex; align-items: center; justify-content: center;
  width: 30px; height: 30px; border-radius: 50%; background: var(--c-navy); color: var(--c-white);
  font-weight: 700; font-size: 0.85rem; flex: none;
}
.flagship__title { font-size: 1.4rem; margin: 6px 0 16px; }
.flagship__layout { display: grid; grid-template-columns: 1fr 300px; gap: 28px; }
.flagship__abstract { font-size: 1rem; color: var(--c-text); }
.flagship__abstract p { color: var(--c-text); }
.flagship__preview { color: var(--c-text-soft); }
.flagship__full { display: none; margin-top: 10px; padding-top: 10px; border-top: 1px dashed var(--c-line); }
.flagship__full.is-open { display: block; }
.flagship__full p { color: var(--c-text); }
.flagship__toggle {
  margin-top: 16px; font-weight: 700; color: var(--c-cyan); font-size: 0.94rem;
  display: inline-flex; align-items: center; gap: 6px;
}
.flagship__toggle::after { content: "展开全文 ▾"; }
.flagship__toggle.is-open::after { content: "收起全文 ▴"; }
.flagship__side { display: flex; flex-direction: column; gap: 14px; }
.flagship__side figure.diagram { padding: 14px; }
.flagship__takeaway {
  background: var(--c-warm-2); border-radius: var(--radius-s); padding: 14px 16px;
  font-size: 0.88rem; color: var(--c-navy); font-weight: 500; border-left: 3px solid var(--c-cyan);
}

/* -------------------- 10. Observation pieces -------------------- */
.observe-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.observe-card {
  background: var(--c-white); border: 1px solid var(--c-line); border-radius: var(--radius-m);
  padding: 24px;
}
.observe-card__date { font-size: 0.8rem; color: var(--c-text-soft); margin-bottom: 8px; }
.observe-card h3 { font-size: 1.08rem; margin-bottom: 10px; }
.observe-card p { font-size: 0.92rem; color: var(--c-text-soft); }

/* -------------------- 11. Article summary cards (flow-back to home) -------------------- */
.article-list { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.article-card {
  background: var(--c-white); border: 1px solid var(--c-line); border-radius: var(--radius-m);
  padding: 22px; display: flex; flex-direction: column; gap: 10px; height: 100%;
}
.article-card__meta { display: flex; gap: 8px; font-size: 0.78rem; color: var(--c-text-soft); }
.article-card h4 { font-size: 1.02rem; line-height: 1.5; }
.article-card p { font-size: 0.9rem; color: var(--c-text-soft); flex: 1; }
.hub-block { margin-bottom: 46px; }
.hub-block__head { display: flex; align-items: baseline; justify-content: space-between; gap: 12px; margin-bottom: 18px; flex-wrap: wrap; }
.hub-block__head h3 { font-size: 1.2rem; }

/* -------------------- 12. Full long-form article (subpages) -------------------- */
.article-full {
  background: var(--c-white); border: 1px solid var(--c-line); border-radius: var(--radius-l);
  padding: 34px; margin-bottom: 26px;
}
.article-full__meta { display: flex; gap: 10px; font-size: 0.82rem; color: var(--c-text-soft); margin-bottom: 10px; flex-wrap: wrap; }
.article-full h2 { font-size: 1.35rem; margin-bottom: 16px; }
.article-full h4 { margin: 18px 0 8px; font-size: 1rem; color: var(--c-navy); }
.article-full .lede { font-size: 1.02rem; color: var(--c-navy); font-weight: 500; margin-bottom: 14px; }
.article-full__back { margin-top: 18px; display: inline-block; }
.callout {
  background: var(--c-warm-2); border-left: 3px solid var(--c-orange); border-radius: var(--radius-s);
  padding: 14px 18px; margin: 16px 0; font-size: 0.94rem;
}
.callout--green { border-left-color: var(--c-green); }
.callout--cyan { border-left-color: var(--c-cyan); }

/* mini data tables inside articles */
.mini-table { font-size: 0.9rem; margin: 14px 0; border: 1px solid var(--c-line); border-radius: var(--radius-s); overflow: hidden; }
.mini-table th, .mini-table td { padding: 9px 12px; border-bottom: 1px solid var(--c-line); text-align: left; }
.mini-table th { background: var(--c-warm-2); color: var(--c-navy); font-weight: 600; }
.mini-table tr:last-child td { border-bottom: none; }
.table-scroll { overflow-x: auto; -webkit-overflow-scrolling: touch; margin: 14px 0; }
.table-scroll .mini-table { margin: 0; min-width: 480px; }

/* -------------------- 13. FAQ -------------------- */
.faq-list { display: flex; flex-direction: column; gap: 10px; }
.faq-item { background: var(--c-white); border: 1px solid var(--c-line); border-radius: var(--radius-s); overflow: hidden; }
.faq-q {
  width: 100%; display: flex; justify-content: space-between; align-items: center; gap: 12px;
  padding: 16px 20px; font-weight: 600; font-size: 0.96rem; text-align: left; color: var(--c-navy);
}
.faq-q::after { content: "+"; font-size: 1.3rem; color: var(--c-cyan); flex: none; transition: transform 0.15s ease; }
.faq-item.is-open .faq-q::after { transform: rotate(45deg); }
.faq-a { max-height: 0; overflow: hidden; transition: max-height 0.22s ease; }
.faq-a p { padding: 0 20px 18px; font-size: 0.92rem; color: var(--c-text-soft); }
.faq-columns { columns: 2; column-gap: 20px; }
.faq-columns .faq-item { break-inside: avoid; margin-bottom: 10px; }

/* -------------------- 14. Tabs (market countries / listing languages) -------------------- */
.tabbar { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 20px; }
.tabbar button {
  padding: 9px 18px; border-radius: 999px; border: 1px solid var(--c-line); font-weight: 600; font-size: 0.9rem;
  background: var(--c-white); color: var(--c-graphite);
}
.tabbar button[aria-selected="true"] { background: var(--c-navy); color: var(--c-white); border-color: var(--c-navy); }
.tabpanel { display: none; }
.tabpanel.is-active { display: block; }

/* -------------------- 15. Matrix / heatmap table -------------------- */
.matrix-table td, .matrix-table th { text-align: center; padding: 12px; }
.matrix-table th { color: var(--c-text-soft); font-weight: 600; font-size: 0.85rem; }
.matrix-table td:first-child, .matrix-table th:first-child { text-align: left; color: var(--c-navy); font-weight: 600; }
.cell { display: inline-block; width: 100%; padding: 8px 0; border-radius: 6px; font-size: 0.82rem; font-weight: 600; }
.cell--l1 { background: rgba(14,165,183,0.12); color: #0B7C89; }
.cell--l2 { background: rgba(14,165,183,0.28); color: #0B7C89; }
.cell--l3 { background: rgba(14,165,183,0.5); color: #06333a; }
.cell--o1 { background: rgba(226,130,46,0.12); color: #a85a1b; }
.cell--o2 { background: rgba(226,130,46,0.30); color: #a85a1b; }
.cell--o3 { background: rgba(226,130,46,0.55); color: #5c3510; }
.cell--g1 { background: rgba(46,158,99,0.12); color: #1f7a4b; }
.cell--g2 { background: rgba(46,158,99,0.30); color: #1f7a4b; }
.cell--g3 { background: rgba(46,158,99,0.55); color: #12492c; }

/* -------------------- 16. Interactive demo panels -------------------- */
.demo-panel {
  background: var(--c-white); border: 1px solid var(--c-line); border-radius: var(--radius-m); padding: 24px;
}
.demo-panel__row { display: flex; gap: 20px; flex-wrap: wrap; }
.filter-controls { display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 18px; }
.filter-controls button {
  padding: 8px 16px; border-radius: 999px; border: 1px solid var(--c-line); font-size: 0.86rem; font-weight: 600;
  background: var(--c-warm-2); color: var(--c-graphite);
}
.filter-controls button.is-active { background: var(--c-green); color: var(--c-white); border-color: var(--c-green); }
.demo-cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.demo-card { border: 1px solid var(--c-line); border-radius: var(--radius-s); padding: 14px; background: var(--c-warm); }
.demo-card[hidden] { display: none; }
.demo-card__score { height: 6px; border-radius: 3px; background: var(--c-line); margin: 8px 0; overflow: hidden; }
.demo-card__score i { display: block; height: 100%; background: var(--c-cyan); }
.demo-card__flag { font-size: 0.78rem; color: var(--c-orange); font-weight: 600; }

.price-chart { position: relative; height: 220px; }
.price-chart svg { width: 100%; height: 100%; }
.price-chart-toggle { display: flex; gap: 8px; margin-bottom: 14px; }

.review-tabs .demo-card { cursor: default; }
.chat-demo { display: flex; flex-direction: column; gap: 12px; max-width: 560px; }
.chat-bubble { padding: 12px 16px; border-radius: var(--radius-m); font-size: 0.92rem; max-width: 82%; }
.chat-bubble--q { align-self: flex-start; background: var(--c-warm-2); color: var(--c-text); border-bottom-left-radius: 4px; }
.chat-bubble--a { align-self: flex-end; background: var(--c-navy); color: var(--c-white); border-bottom-right-radius: 4px; }
.chat-bubble--a .evidence { display: flex; gap: 6px; margin-top: 8px; flex-wrap: wrap; }
.chat-bubble--a .evidence span { font-size: 0.72rem; background: rgba(255,255,255,0.14); padding: 2px 8px; border-radius: 999px; }
.chat-quick { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 14px; }
.chat-quick button { border: 1px solid var(--c-line); border-radius: 999px; padding: 7px 14px; font-size: 0.84rem; background: var(--c-white); }
.chat-quick button:hover { border-color: var(--c-cyan); color: var(--c-cyan); }

/* -------------------- 17. App feature grid & download -------------------- */
.app-feature-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.app-feature {
  background: var(--c-white); border: 1px solid var(--c-line); border-radius: var(--radius-m); padding: 20px;
  text-align: center;
}
.app-feature img { width: 56px; height: 56px; margin: 0 auto 12px; }
.app-feature h4 { font-size: 0.98rem; }
.app-feature p { font-size: 0.84rem; color: var(--c-text-soft); }

.download-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.download-card {
  background: var(--c-white); border: 1px solid var(--c-line); border-radius: var(--radius-m); padding: 26px;
  text-align: center;
}
.download-card img { width: 96px; height: 96px; margin: 0 auto 14px; }
.download-card h4 { margin-bottom: 6px; }
.download-card p { font-size: 0.86rem; color: var(--c-text-soft); margin-bottom: 14px; }
.download-note {
  margin-top: 22px; font-size: 0.86rem; color: var(--c-text-soft); background: var(--c-warm-2);
  padding: 14px 18px; border-radius: var(--radius-s);
}

/* -------------------- 18. Company / disclaimer -------------------- */
.company-block { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; align-items: center; }
.company-facts { list-style: none; margin-top: 16px; display: flex; flex-direction: column; gap: 8px; font-size: 0.92rem; }
.company-facts b { color: var(--c-navy); display: inline-block; width: 96px; }
.disclaimer {
  font-size: 0.82rem; color: var(--c-text-soft); background: var(--c-warm-2); padding: 18px 20px;
  border-radius: var(--radius-s); margin-top: 22px;
}

/* -------------------- 19. Footer -------------------- */
.site-footer { background: var(--c-navy); color: rgba(255,255,255,0.82); padding: 48px 0 26px; margin-top: 40px; }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 32px; }
.footer-brand { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; }
.footer-brand img { width: 32px; height: 32px; }
.footer-brand span { color: #fff; font-weight: 700; }
.site-footer p { font-size: 0.85rem; color: rgba(255,255,255,0.62); }
.footer-col h5 { color: #fff; font-size: 0.92rem; margin-bottom: 14px; }
.footer-col a { display: block; font-size: 0.86rem; color: rgba(255,255,255,0.72); margin-bottom: 10px; }
.footer-col a:hover { color: #fff; }
.footer-bottom {
  margin-top: 34px; padding-top: 22px; border-top: 1px solid rgba(255,255,255,0.14);
  font-size: 0.78rem; color: rgba(255,255,255,0.55); display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px;
}

/* -------------------- 20. Back to top -------------------- */
.back-to-top {
  position: fixed; right: 22px; bottom: 26px; width: 46px; height: 46px; border-radius: 50%;
  background: var(--c-navy); color: #fff; display: flex; align-items: center; justify-content: center;
  box-shadow: var(--shadow-card); opacity: 0; pointer-events: none; transition: opacity 0.2s ease, transform 0.2s ease;
  z-index: 150; font-size: 1.1rem;
}
.back-to-top.is-visible { opacity: 1; pointer-events: auto; }
.back-to-top:hover { transform: translateY(-3px); }

/* -------------------- 21. Signal chain / process list -------------------- */
.process-steps { display: flex; flex-direction: column; gap: 0; }
.process-step { display: flex; gap: 16px; padding: 14px 0; border-bottom: 1px dashed var(--c-line); }
.process-step:last-child { border-bottom: none; }
.process-step__num {
  width: 30px; height: 30px; border-radius: 50%; background: var(--c-warm-2); color: var(--c-navy);
  display: flex; align-items: center; justify-content: center; font-weight: 700; font-size: 0.85rem; flex: none;
}
.process-step h4 { font-size: 0.98rem; margin-bottom: 4px; }
.process-step p { font-size: 0.88rem; color: var(--c-text-soft); }

/* -------------------- 22. Grid helpers -------------------- */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.align-center { align-items: center; }

/* -------------------- 23. Utility -------------------- */
.text-soft { color: var(--c-text-soft); }
.mt-0 { margin-top: 0; }
.mt-24 { margin-top: 24px; }
.small { font-size: 0.86rem; }
.center { text-align: center; }

/* ==========================================================================
   Responsive
   ========================================================================== */
@media (max-width: 1024px) {
  .hero__grid { grid-template-columns: 1fr; }
  .hero__figure { order: -1; }
  .flagship__layout { grid-template-columns: 1fr; }
  .observe-grid { grid-template-columns: 1fr 1fr; }
  .article-list { grid-template-columns: 1fr 1fr; }
  .app-feature-grid { grid-template-columns: repeat(2, 1fr); }
  .download-grid { grid-template-columns: 1fr 1fr 1fr; gap: 14px; }
  .company-block { grid-template-columns: 1fr; }
  .grid-2 { grid-template-columns: 1fr; }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 26px; }
}

@media (max-width: 768px) {
  .main-nav { display: none; position: absolute; top: 72px; left: 0; right: 0; background: var(--c-warm);
    flex-direction: column; align-items: stretch; padding: 10px 20px 20px; border-bottom: 1px solid var(--c-line);
    box-shadow: var(--shadow-card); }
  .main-nav.is-open { display: flex; }
  .main-nav a { padding: 13px 14px; border-radius: 10px; }
  .nav-toggle { display: flex; }
  .hero h1 { font-size: 1.7rem; }
  .observe-grid { grid-template-columns: 1fr; }
  .article-list { grid-template-columns: 1fr; }
  .demo-cards { grid-template-columns: 1fr; }
  .figure-2col { grid-template-columns: 1fr; }
  .faq-columns { columns: 1; }
  .download-grid { grid-template-columns: 1fr; }
  .app-feature-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  section.section { padding: 44px 0; }
}

@media (max-width: 480px) {
  .container { padding: 0 16px; }
  .hero { padding: 36px 0 32px; }
  .hero h1 { font-size: 1.42rem; }
  h2 { font-size: 1.32rem; }
  .flagship { padding: 20px; }
  .flagship__title { font-size: 1.18rem; }
  .article-full { padding: 22px; }
  .grid-4, .grid-3 { grid-template-columns: 1fr 1fr; }
  .app-feature-grid { grid-template-columns: 1fr 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 24px; }
  .footer-bottom { flex-direction: column; }
  .chain-strip { padding: 12px; }
  .back-to-top { right: 14px; bottom: 16px; width: 40px; height: 40px; }
}