:root {
  --dark: #0f172a;
  --fog: #e2e8f0;
  --ice: #f8fafc;
  --line: #94a3b8;
  --slate: #1e293b;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font: 16px/1.7 "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--fog);
  color: #0f172a;
}
.site-header {
  display: grid;
  grid-template-columns: 1fr 1fr;
  align-items: center;
  padding: 0;
  position: sticky;
  top: 0;
  z-index: 5;
}
.site-header .brand {
  background: var(--dark);
  color: #e2e8f0;
  padding: 14px 22px;
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  height: 100%;
}
.site-header nav {
  background: var(--ice);
  padding: 14px 22px;
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  justify-content: flex-end;
}
nav a {
  color: #334155;
  text-decoration: none;
  font-size: 13px;
}
nav a:hover {
  color: #0f172a;
  text-decoration: underline;
}
.hero-duo,
.half {
  display: grid;
  grid-template-columns: 1fr 1fr;
}
.pane { padding: 28px 24px; }
.pane.watch {
  background: var(--dark);
  color: #e2e8f0;
}
.pane.watch h2,
.pane.watch h3,
.pane.watch p { color: #e2e8f0; }
.pane.webp {
  background: var(--ice);
  color: #0f172a;
}
.kicker {
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 8px;
  opacity: 0.8;
}
.hero-duo h1 {
  font-size: 28px;
  line-height: 1.35;
  margin: 8px 0 12px;
}
.card {
  margin-top: 14px;
  padding: 14px;
  border-radius: 0;
}
.watch .card { background: var(--slate); }
.webp .card {
  background: #fff;
  border: 1px solid #cbd5e1;
}
.card svg { display: block; margin-bottom: 6px; }
.watch .card svg { color: #94a3b8; }
.webp .card svg { color: #334155; }
.watch .card:hover { background: #334155; }
.webp .card:hover { border-color: #0f172a; }
.band {
  padding: 28px 24px;
  background: #cbd5e1;
}
.band h2 { margin-bottom: 10px; }
.band p { max-width: 900px; margin-bottom: 10px; }
.steps {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  margin-top: 14px;
}
.steps li {
  background: #fff;
  padding: 12px;
  display: flex;
  gap: 10px;
}
.steps span {
  width: 28px;
  height: 28px;
  background: var(--dark);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  flex: 0 0 28px;
}
table {
  width: 100%;
  border-collapse: collapse;
  background: #fff;
  margin-top: 12px;
  font-size: 14px;
}
th, td {
  border: 1px solid var(--line);
  padding: 10px;
  vertical-align: top;
}
th {
  background: var(--dark);
  color: #e2e8f0;
}
td:nth-child(2) { background: #0f172a; color: #e2e8f0; }
td:nth-child(3) { background: #f8fafc; }
.faq { padding: 28px 24px; background: var(--ice); }
.faq details {
  background: #fff;
  margin: 8px 0;
  padding: 12px 14px;
  border: 1px solid #cbd5e1;
}
.faq summary { cursor: pointer; font-weight: 600; }
.faq details p { margin-top: 8px; }
.site-footer {
  padding: 24px;
  background: var(--dark);
  color: #cbd5e1;
  font-size: 13px;
}
.site-footer p { margin: 6px 0; }
@media (max-width: 860px) {
  .site-header,
  .hero-duo,
  .half,
  .steps { grid-template-columns: 1fr; }
  .site-header nav { justify-content: flex-start; }
  .hero-duo h1 { font-size: 22px; }
  td:nth-child(2) { background: #1e293b; }
}