:root {
  color-scheme: light dark;
  --canvas: #f5f7fa;
  --surface: #ffffff;
  --surface-strong: #101b2d;
  --ink: #111b2c;
  --muted: #5d6b7d;
  --line: #d9e0e8;
  --accent: #315b8c;
  --accent-deep: #23456e;
  --accent-soft: #e8eef6;
  --on-dark: #f7f9fc;
  --on-dark-muted: #bcc8d7;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-synthesis: none;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scrollbar-color: var(--accent) var(--canvas); scrollbar-width: thin; }
body { margin: 0; background: var(--canvas); color: var(--ink); font-size: 16px; line-height: 1.7; overflow-wrap: anywhere; }
a { color: inherit; text-underline-offset: .24em; }
img { display: block; max-width: 100%; }
::selection { background: var(--accent); color: #fff; }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 4px; }
.shell { width: min(100% - 48px, 1180px); margin-inline: auto; }
.skip-link { position: fixed; top: 10px; left: 10px; z-index: 10; min-height: 44px; display: inline-flex; align-items: center; padding: 8px 14px; background: var(--surface-strong); color: var(--on-dark); transform: translateY(-160%); }
.skip-link:focus { transform: translateY(0); }

.site-header { border-bottom: 1px solid var(--line); }
.masthead { min-height: 76px; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.wordmark { display: inline-flex; align-items: center; gap: 10px; font-weight: 820; letter-spacing: .04em; text-decoration: none; }
.wordmark-dot { width: 12px; height: 12px; border-radius: 50%; background: var(--accent); box-shadow: 0 0 0 7px var(--accent-soft); }
.top-nav { display: flex; gap: 24px; }
.top-nav a { min-height: 44px; display: inline-flex; align-items: center; color: var(--muted); text-decoration: none; }
.top-nav a:hover { color: var(--ink); }

.hero { min-height: 620px; display: grid; grid-template-columns: minmax(0, 1.2fr) minmax(330px, .8fr); align-items: center; gap: clamp(48px, 8vw, 120px); padding-block: clamp(72px, 10vw, 128px); }
.hero h1 { max-width: 14ch; margin: 0; font-size: clamp(3rem, 5.4vw, 4.9rem); font-weight: 680; letter-spacing: -.04em; line-height: 1.02; text-wrap: balance; }
.hero h1 span { display: block; white-space: nowrap; }
.hero-lead { max-width: 38rem; margin: 28px 0 0; color: var(--muted); font-size: clamp(1.05rem, 1.7vw, 1.24rem); }
.hero-downloads { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 24px; }
.hero-downloads a { min-height: 46px; display: inline-flex; align-items: center; padding: 9px 16px; border: 1px solid var(--line); border-radius: 10px; color: var(--accent); font-weight: 760; text-decoration: none; }
.hero-downloads a:first-child { border-color: var(--accent); background: var(--accent); color: #fff; }
.product-index { padding: 14px 24px; border-radius: 26px; background: var(--surface-strong); color: var(--on-dark); }
.product-index a { min-height: 118px; display: grid; grid-template-columns: 56px 1fr auto; align-items: center; gap: 18px; padding: 24px 0; text-decoration: none; }
.product-index a + a { border-top: 1px solid rgba(255,255,255,.15); }
.product-index img { border-radius: 15px; }
.product-index small { display: block; margin-bottom: 2px; color: var(--on-dark-muted); font-size: .76rem; letter-spacing: .06em; }
.product-index strong { font-size: 1.2rem; }
.product-index b { color: #70839c; font-size: .8rem; font-variant-numeric: tabular-nums; }
.product-index a:hover strong { color: #a9c9ee; }

.product-list { border-top: 1px solid var(--line); }
.product-row { display: grid; grid-template-columns: 76px minmax(260px, .85fr) minmax(0, 1.15fr); gap: clamp(24px, 4.5vw, 68px); padding: clamp(54px, 8vw, 96px) 0; border-bottom: 1px solid var(--line); }
.product-number { color: var(--muted); font-size: .78rem; font-variant-numeric: tabular-nums; }
.product-title { display: flex; align-items: flex-start; gap: 20px; }
.product-title img { border-radius: 20px; box-shadow: 0 14px 34px rgba(33,56,86,.14); }
.product-title h2 { margin: 0; font-size: clamp(2rem, 4vw, 3.5rem); font-weight: 680; letter-spacing: -.04em; line-height: 1.02; }
.product-detail > p:first-child { max-width: 58ch; margin: 0; color: var(--muted); font-size: 1.02rem; }
.actions { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; margin-top: 26px; }
.button { min-height: 48px; display: inline-flex; align-items: center; justify-content: center; padding: 10px 18px; border-radius: 10px; font-weight: 760; text-decoration: none; }
.button-primary { background: var(--accent); color: #fff; transition: background 160ms ease, transform 160ms ease; }
.button-primary:hover { background: var(--accent-deep); transform: translateY(-2px); }
.button-disabled { border: 1px solid var(--line); background: transparent; color: var(--muted); cursor: default; }
.text-link { min-height: 48px; display: inline-flex; align-items: center; padding-inline: 8px; color: var(--accent); font-weight: 720; }
.file-note { margin: 15px 0 0; color: var(--muted); font-family: ui-monospace, Consolas, monospace; font-size: .78rem; }

.trust-band { background: var(--surface-strong); color: var(--on-dark); }
.trust-grid { display: grid; grid-template-columns: minmax(240px, .8fr) minmax(0, 1.2fr); gap: clamp(40px, 8vw, 128px); padding-block: clamp(64px, 9vw, 110px); }
.trust-grid h2 { max-width: 10ch; margin: 0; font-size: clamp(2.2rem, 5vw, 4.5rem); font-weight: 650; letter-spacing: -.04em; line-height: 1.02; }
.trust-grid h2 span { display: block; white-space: nowrap; }
.trust-grid dl { margin: 0; }
.trust-grid dl div { display: grid; grid-template-columns: 120px 1fr; gap: 24px; padding: 22px 0; border-bottom: 1px solid rgba(255,255,255,.14); }
.trust-grid dl div:first-child { padding-top: 0; }
.trust-grid dt { font-weight: 760; }
.trust-grid dd { margin: 0; color: var(--on-dark-muted); }

.site-footer { background: var(--surface); }
.footer-grid { min-height: 150px; display: flex; justify-content: space-between; gap: 36px; padding-block: 36px; }
.footer-grid p { margin: 5px 0 0; color: var(--muted); font-size: .9rem; }
.footer-grid nav { display: flex; flex-wrap: wrap; align-content: flex-start; justify-content: flex-end; gap: 10px 22px; }
.footer-grid nav a { min-height: 44px; display: inline-flex; align-items: center; color: var(--muted); font-size: .9rem; }

@media (max-width: 820px) {
  .shell { width: min(100% - 30px, 720px); }
  .hero { min-height: auto; grid-template-columns: 1fr; gap: 42px; padding-block: 58px 72px; }
  .hero h1 { font-size: clamp(2.45rem, 10.4vw, 4rem); }
  .product-index { padding-inline: 20px; }
  .product-row { grid-template-columns: 42px 1fr; }
  .product-detail { grid-column: 2; }
  .trust-grid { grid-template-columns: 1fr; }
  .trust-grid h2 { max-width: 14ch; }
}

@media (max-width: 540px) {
  .masthead { min-height: 68px; }
  .top-nav { gap: 14px; }
  .hero { padding-top: 46px; }
  .hero-lead { margin-top: 20px; }
  .hero-downloads { display: grid; grid-template-columns: 1fr 1fr; }
  .hero-downloads a { justify-content: center; padding-inline: 10px; font-size: .9rem; }
  .product-index a { min-height: 100px; padding-block: 18px; }
  .product-row { grid-template-columns: 1fr; gap: 22px; }
  .product-number { display: none; }
  .product-detail { grid-column: auto; }
  .product-title { align-items: center; }
  .product-title img { width: 64px; height: 64px; }
  .actions { align-items: stretch; flex-direction: column; }
  .button, .text-link { width: 100%; }
  .trust-grid dl div { grid-template-columns: 1fr; gap: 5px; }
  .footer-grid { flex-direction: column; }
  .footer-grid nav { justify-content: flex-start; }
}

@media (prefers-color-scheme: dark) {
  :root {
    --canvas: #0b121d;
    --surface: #101a28;
    --surface-strong: #07101b;
    --ink: #f1f5fa;
    --muted: #a5b2c3;
    --line: #273549;
    --accent: #76a4d7;
    --accent-deep: #5e91c9;
    --accent-soft: #1a2d43;
  }
  .button-primary { color: #07101b; }
  .product-title img { box-shadow: 0 14px 34px rgba(0,0,0,.28); }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .button-primary { transition: none; }
  .button-primary:hover { transform: none; }
  .skip-link { transition: none; }
}