:root {
  --bg: #0b0f19;
  --card: #11182a;
  --text: #e7eefc;
  --muted: rgba(231, 238, 252, 0.75);
  --border: rgba(231, 238, 252, 0.12);
  --link: #8ab4ff;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  font-family:
    ui-sans-serif,
    system-ui,
    -apple-system,
    Segoe UI,
    Roboto,
    Arial,
    "Noto Sans",
    "Helvetica Neue",
    sans-serif;
  background:
    radial-gradient(
      1200px 600px at 10% 0%,
      rgba(138, 180, 255, 0.18),
      transparent 60%
    ),
    radial-gradient(
      900px 500px at 90% 10%,
      rgba(111, 247, 199, 0.12),
      transparent 55%
    ),
    var(--bg);
  color: var(--text);
  line-height: 1.6;
}

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

.container {
  width: min(980px, calc(100% - 32px));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(10px);
  background: rgba(11, 15, 25, 0.65);
  border-bottom: 1px solid var(--border);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 0;
  gap: 16px;
}

.brand {
  font-weight: 700;
  letter-spacing: 0.2px;
  color: var(--text);
}

.nav {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

.nav a {
  padding: 6px 10px;
  border-radius: 10px;
  border: 1px solid transparent;
  color: var(--muted);
}

.nav a.active {
  color: var(--text);
  border-color: var(--border);
  background: rgba(255, 255, 255, 0.03);
}

.card {
  margin: 28px 0 22px;
  padding: 28px;
  background: rgba(17, 24, 42, 0.72);
  border: 1px solid var(--border);
  border-radius: 18px;
  box-shadow: var(--shadow);
}

h1 {
  margin: 0 0 10px;
  font-size: clamp(26px, 3vw, 34px);
  line-height: 1.2;
}

h2 {
  margin-top: 24px;
  margin-bottom: 8px;
  font-size: 18px;
}

h3 {
  margin-top: 18px;
  margin-bottom: 8px;
  font-size: 15px;
  color: var(--text);
}

p {
  margin: 10px 0;
}

ul {
  margin: 10px 0 10px 20px;
  padding: 0;
}

li {
  margin: 6px 0;
}

.muted {
  color: var(--muted);
}

.note {
  margin-top: 14px;
  padding: 12px 14px;
  border: 1px dashed rgba(231, 238, 252, 0.18);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.03);
}

.footer {
  padding: 18px 0 40px;
  border-top: 1px solid var(--border);
  margin-top: 20px;
}