:root {
  --bg: #0b1220;
  --card: #111c36;
  --border: rgba(255,255,255,.08);
  --text: #ffffff;
  --muted: rgba(255,255,255,.7);
  --primary: #4fd0e9;
  --radius: 16px;
  --shadow: 0 12px 30px rgba(0,0,0,.35);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  background: linear-gradient(180deg, #0b1220 0%, #0e1630 100%);
  color: var(--text);
}

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

/* HEADER --------------------------------------------------- */
.header {
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(10px);
  background: rgba(11,18,32,.85);
  border-bottom: 1px solid var(--border);
}

.header__inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.header__brand {
  font-weight: 700;
  letter-spacing: .3px;
}

.header__nav a {
  margin-left: 1rem;
  font-weight: 500;
  color: var(--muted);
}
.header__nav a:hover { color: var(--text); }

/* HERO ----------------------------------------------------- */
.hero {
  padding: 5rem 1rem 3rem;
  text-align: center;
}

.hero h1 {
  max-width: 720px;
  margin: 0 auto 1rem;
  font-size: 2.2rem;
}

.hero p {
  max-width: 640px;
  margin: 0 auto;
  color: var(--muted);
}

/* CARDS ---------------------------------------------------- */
.cards {
  max-width: 1000px;
  margin: 0 auto;
  padding: 2rem 1rem 4rem;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px,1fr));
  gap: 1.5rem;
}

.card {
  background: var(--card);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
}

.card h3 { margin-top: 0; }

/* DOC ------------------------------------------------------ */
.doc {
  max-width: 820px;
  margin: 0 auto;
  padding: 3rem 1rem 5rem;
}

.doc h1 { margin-top: 0; }
.doc h2 {
  margin-top: 2.5rem;
  color: var(--primary);
}

.doc p, .doc li {
  line-height: 1.7;
  color: var(--muted);
}

.doc ul { padding-left: 1.2rem; }

/* FOOTER --------------------------------------------------- */
.footer {
  text-align: center;
  padding: 3rem 1rem 4rem;
  color: var(--muted);
  border-top: 1px solid var(--border);
  font-size: .95rem;
}