/* Set 6 — app: dark storefront, stacked device cards */
:root {
  --bg: #12141a;
  --panel: #1c1f2a;
  --ink: #e8ebf4;
  --dim: #9aa3b8;
  --line: #2c3142;
  --blue: #5b8cff;
  --blue-d: #3a66d4;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  line-height: 1.7;
  font-size: 15.5px;
}
a { color: var(--blue); }
.appbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 22px;
  background: #0e1016;
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  z-index: 5;
}
.brand {
  color: #fff;
  text-decoration: none;
  font-weight: 800;
  font-size: 20px;
}
.nav a {
  color: var(--dim);
  text-decoration: none;
  margin-left: 14px;
  font-size: 14px;
}
.nav a.is-current { color: #fff; background: var(--panel); padding: 6px 10px; border-radius: 8px; }
.hero-app {
  width: min(980px, calc(100% - 28px));
  margin: 28px auto 20px;
  background: radial-gradient(circle at 20% 20%, #243056, var(--panel));
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 32px 28px;
}
h1 { font-size: clamp(24px, 3vw, 32px); margin: 0 0 12px; }
.lead { color: var(--dim); }
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--blue);
  color: #fff;
  text-decoration: none;
  padding: 12px 18px;
  border-radius: 10px;
  font-weight: 700;
  margin-top: 16px;
}
.btn:hover { background: var(--blue-d); color: #fff; }
.shelf {
  width: min(980px, calc(100% - 28px));
  margin: 0 auto 22px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}
.shelf article {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 14px;
  font-size: 14px;
}
.panel-stack {
  width: min(980px, calc(100% - 28px));
  margin: 0 auto 18px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 22px 22px 8px;
}
h2 { font-size: 19px; margin: 0 0 10px; color: #fff; }
.mono {
  font-family: Consolas, "Courier New", monospace;
  font-size: 12px;
  color: var(--blue);
  letter-spacing: 0.08em;
}
.icon { width: 16px; height: 16px; fill: currentColor; }
.faq-list { width: min(980px, calc(100% - 28px)); margin: 0 auto 28px; }
.faq-item { background: var(--panel); border: 1px solid var(--line); border-radius: 10px; padding: 14px 16px; margin: 8px 0; }
.faq-item h3 { margin: 0 0 6px; font-size: 15px; color: #fff; }
.site-footer {
  width: min(980px, calc(100% - 28px));
  margin: 10px auto 40px;
  color: var(--dim);
  font-size: 13px;
  border-top: 1px solid var(--line);
  padding-top: 18px;
}
.site-footer nav { display: flex; gap: 14px; margin: 8px 0 12px; }
.req-table { width: 100%; border-collapse: collapse; }
.req-table th, .req-table td { border: 1px solid var(--line); padding: 8px; }
.req-table th { background: #161924; }
@media (max-width: 800px) {
  .shelf { grid-template-columns: 1fr 1fr; }
  .appbar { flex-wrap: wrap; gap: 8px; }
}