:root {
  --bg: #030816;
  --bg-2: #061033;
  --bg-card: rgba(10, 22, 58, 0.82);
  --line: rgba(120, 160, 255, 0.28);
  --text: #f0f5ff;
  --muted: #8fa3d0;
  --brand: #2554e8;
  --brand-2: #4d7cff;
  --cyan: #7ec8ff;
  --hot: #ffb457;
  --ok: #5b9bff;
  --wrap: 1200px;
  --radius: 14px;
  --font: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  background:
    radial-gradient(ellipse 80% 40% at 85% 0%, rgba(56, 120, 255, 0.28), transparent 55%),
    radial-gradient(ellipse 60% 30% at 10% 8%, rgba(14, 80, 200, 0.22), transparent 50%),
    linear-gradient(180deg, #061033 0%, #050d28 35%, #040a1f 70%, #030816 100%);
  color: var(--text);
  line-height: 1.65;
  min-height: 100vh;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--cyan); text-decoration: none; }
a:hover { text-decoration: underline; }
.wrap {
  width: min(var(--wrap), calc(100% - 40px));
  margin: 0 auto;
}
.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(14px);
  background: rgba(3, 8, 22, 0.78);
  border-bottom: 1px solid rgba(120, 160, 255, 0.16);
}
.site-header .inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 0;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: #fff;
  text-decoration: none;
}
.brand:hover { text-decoration: none; }
.brand img {
  width: 40px;
  height: 40px;
  border-radius: 11px;
  box-shadow: 0 0 18px rgba(77, 124, 255, 0.45);
}
.brand strong {
  display: block;
  font-size: 18px;
  letter-spacing: 2px;
}
.brand small {
  display: block;
  font-size: 12px;
  color: #8fb0ff;
  font-weight: 500;
  letter-spacing: 0.5px;
}
.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  align-items: center;
}
.nav a {
  color: #c5d6ff;
  font-size: 14px;
  font-weight: 600;
}
.nav a:hover,
.nav a.active { color: #fff; text-decoration: none; }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 18px;
  border-radius: 10px;
  font-size: 14px;
  font-weight: 700;
  border: 1px solid transparent;
  text-decoration: none;
  cursor: pointer;
  transition: 0.15s ease;
}
.btn:hover { text-decoration: none; }
.btn-primary {
  background: linear-gradient(90deg, #1b4fe0, #3a78ff);
  color: #fff;
  box-shadow: 0 8px 24px rgba(37, 84, 232, 0.35);
}
.btn-primary:hover { filter: brightness(1.06); }
.btn-ghost {
  background: rgba(15, 30, 80, 0.65);
  border-color: rgba(120, 170, 255, 0.3);
  color: #c5d6ff;
}
.btn-ghost:hover {
  border-color: rgba(126, 200, 255, 0.55);
  color: #fff;
}
.btn-hot {
  background: linear-gradient(90deg, #e8872a, #ffb457);
  color: #1a1208;
}
.site-footer {
  margin-top: 64px;
  border-top: 1px solid rgba(120, 160, 255, 0.16);
  padding: 28px 0 40px;
  color: var(--muted);
  font-size: 13px;
}
.site-footer .inner {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 24px;
  justify-content: space-between;
}
.section { padding: 56px 0 8px; }
.section h2 {
  font-size: 28px;
  font-weight: 900;
  letter-spacing: 1px;
  margin-bottom: 10px;
}
.section .lead {
  color: var(--muted);
  max-width: 720px;
  margin-bottom: 28px;
}
.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}
.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}
.card {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px 18px;
}
.card h3 {
  font-size: 17px;
  margin-bottom: 8px;
}
.card p,
.card li { color: #a8bbe8; font-size: 14px; }
.card ol,
.card ul { padding-left: 18px; }
.card li { margin: 6px 0; }
.tag {
  display: inline-block;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 1px;
  color: var(--cyan);
  margin-bottom: 8px;
}
@media (max-width: 960px) {
  .grid-3,
  .grid-4 { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 640px) {
  .grid-3,
  .grid-4 { grid-template-columns: 1fr; }
  .brand small { display: none; }
  .section h2 { font-size: 22px; }
}