:root {
  --slate: #2c3338;
  --slate-d: #1e2428;
  --sky: #4a90c8;
  --sky-d: #2f6f9e;
  --line: #d5dde3;
  --bg: #eef2f5;
  --ink: #243038;
  --mute: #5d6b75;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  background: var(--bg);
  color: var(--ink);
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 15px;
  line-height: 1.7;
}

a { color: var(--sky-d); text-decoration: none; }
a:hover { text-decoration: underline; }

.sticky {
  position: sticky;
  top: 0;
  z-index: 20;
  background: var(--slate-d);
  color: #d7e0e6;
  border-bottom: 2px solid var(--sky);
}

.sticky .row {
  width: min(1200px, calc(100% - 28px));
  margin: 0 auto;
  min-height: 52px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 8px;
  color: #fff;
  font-size: 16px;
  font-weight: 700;
  letter-spacing: 0.04em;
}

.brand svg { width: 20px; height: 20px; }

.nav { display: flex; gap: 18px; }

.nav a {
  color: #c5d0d7;
  font-size: 13px;
  text-transform: none;
  padding-bottom: 2px;
  border-bottom: 2px solid transparent;
}

.nav a.is-current { color: #fff; border-bottom-color: var(--sky); }

.canvas { width: min(1200px, calc(100% - 28px)); margin: 20px auto 48px; }

.hero-panel {
  background: #fff;
  border: 1px solid var(--line);
  padding: 28px 28px 22px;
  display: grid;
  grid-template-columns: 1.4fr 0.8fr;
  gap: 24px;
}

h1 { font-size: 28px; line-height: 1.35; margin-bottom: 12px; }

.lead { color: var(--mute); margin-bottom: 16px; }

.cta-row { display: flex; flex-wrap: wrap; gap: 8px; }

.btn {
  display: inline-block;
  padding: 10px 16px;
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
}

.btn-main { background: var(--sky); color: #fff; }
.btn-main:hover { background: var(--sky-d); color: #fff; text-decoration: none; }
.btn-sub { background: var(--slate); color: #fff; }

.side-note {
  background: var(--slate);
  color: #d7e0e6;
  padding: 16px;
  font-size: 13px;
}

.side-note strong { color: #fff; display: block; margin-bottom: 8px; }

.chooser {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin: 16px 0;
}

.chooser a, .chooser .tile {
  background: #fff;
  border: 1px solid var(--line);
  padding: 16px;
  display: block;
  color: inherit;
}

.chooser h3 { font-size: 16px; color: var(--sky-d); margin-bottom: 6px; }

.mod {
  background: #fff;
  border: 1px solid var(--line);
  border-top: 4px solid var(--slate);
  padding: 22px 22px 14px;
  margin: 16px 0;
}

.mod h2 {
  font-size: 18px;
  color: var(--slate);
  margin-bottom: 10px;
  padding-bottom: 8px;
  border-bottom: 1px dashed var(--line);
}

.mod p { margin-bottom: 12px; }

table {
  width: 100%;
  border-collapse: collapse;
  margin: 10px 0 14px;
  font-size: 14px;
}

th, td { border: 1px solid var(--line); padding: 8px 10px; text-align: left; }
th { background: var(--slate); color: #fff; }

.faq-item { margin: 14px 0; padding-left: 12px; border-left: 3px solid var(--sky); }
.faq-item h3 { font-size: 15px; margin-bottom: 4px; }

.dl-strip { display: flex; flex-wrap: wrap; gap: 8px; margin: 10px 0; }

.site-foot {
  background: var(--slate-d);
  color: #9aabB6;
  padding: 20px 0 24px;
  font-size: 12px;
}

.site-foot .row { width: min(1200px, calc(100% - 28px)); margin: 0 auto; }
.site-foot a { color: #d7e0e6; }
.site-foot .safe { color: #8ec3e6; margin: 8px 0; }

@media (max-width: 840px) {
  .hero-panel, .chooser { grid-template-columns: 1fr; }
  h1 { font-size: 22px; }
  .sticky .row { flex-wrap: wrap; padding: 8px 0; }
}