/* 第5套 web：深色工具站 + 顶栏固定下载条 */
:root {
  --s5-bg: #12141a;
  --s5-panel: #1b1f29;
  --s5-ink: #e8edf5;
  --s5-mute: #9aa6b8;
  --s5-line: #2c3342;
  --s5-cyan: #3ee0c5;
  --s5-cyan-d: #20b89f;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: auto; }
body {
  margin: 0;
  background: var(--s5-bg);
  color: var(--s5-ink);
  font-family: "Segoe UI", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.75;
  padding-top: 58px;
}
img, svg { max-width: 100%; vertical-align: middle; }
a { color: var(--s5-cyan); }
a:hover { color: #7ff0dc; }

.s5-fixed {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 20;
  background: #0e1016;
  border-bottom: 1px solid var(--s5-line);
}
.s5-fixed-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 8px 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  min-height: 58px;
}
.s5-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 0;
  font-size: 18px;
  font-weight: 700;
  color: #fff;
}
.s5-nav a {
  color: var(--s5-mute);
  text-decoration: none;
  margin-left: 12px;
}
.s5-nav a.is-current { color: var(--s5-cyan); }
.s5-mini {
  background: var(--s5-cyan);
  color: #10231f;
  text-decoration: none;
  padding: 8px 12px;
  border-radius: 6px;
  font-weight: 800;
  white-space: nowrap;
}
.s5-mini:hover { background: var(--s5-cyan-d); color: #10231f; }

.s5-wrap { max-width: 1100px; margin: 0 auto; padding: 24px 16px 48px; }
.s5-hero {
  background: var(--s5-panel);
  border: 1px solid var(--s5-line);
  padding: 28px;
  border-radius: 10px;
}
.s5-hero h1 { margin: 0 0 12px; font-size: 28px; }
.s5-sec { margin-top: 26px; }
.s5-sec h2 { font-size: 21px; margin: 0 0 10px; }
.s5-split { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.s5-box {
  background: var(--s5-panel);
  border: 1px solid var(--s5-line);
  padding: 16px;
  border-radius: 8px;
}
.s5-btn {
  display: inline-block;
  background: var(--s5-cyan);
  color: #10231f;
  text-decoration: none;
  padding: 10px 16px;
  border-radius: 6px;
  font-weight: 800;
}
.s5-btn:hover { background: var(--s5-cyan-d); color: #10231f; }
.s5-btn-ghost {
  display: inline-block;
  border: 1px solid var(--s5-line);
  color: var(--s5-ink);
  text-decoration: none;
  padding: 9px 14px;
  border-radius: 6px;
}
.s5-faq dt { font-weight: 700; margin-top: 14px; }
.s5-faq dd { margin: 6px 0 0; color: var(--s5-mute); }
.s5-foot {
  border-top: 1px solid var(--s5-line);
  color: var(--s5-mute);
  font-size: 13px;
  padding: 18px 16px 32px;
  max-width: 1100px;
  margin: 0 auto;
}

@media (max-width: 800px) {
  .s5-split { grid-template-columns: 1fr; }
  .s5-fixed-inner { flex-wrap: wrap; }
  .s5-nav { width: 100%; }
}