:root {
  --bg: #0f1115;
  --panel: #171a21;
  --panel-2: #1d2230;
  --text: #eef2ff;
  --muted: #aeb6cf;
  --line: #2c3346;
  --accent: #7aa2ff;
  --accent-2: #9f7aea;
  --success: #3ddc97;
  --warn: #ffcc66;
  --danger: #ff7a7a;
  --shadow: 0 16px 40px rgba(0, 0, 0, 0.28);
  --radius: 18px;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  background:
    radial-gradient(circle at top left, rgba(122, 162, 255, 0.14), transparent 28%),
    radial-gradient(circle at top right, rgba(159, 122, 234, 0.12), transparent 26%),
    var(--bg);
  color: var(--text);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.6;
}

.page {
  max-width: 900px;
  margin: 0 auto;
  padding: 40px 24px;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

header {
  background: linear-gradient(135deg, rgba(122, 162, 255, 0.16), rgba(159, 122, 234, 0.12));
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 30px;
  text-align: center;
}

h1 {
  margin: 0 0 10px;
  font-size: 32px;
  font-weight: 800;
  letter-spacing: 0.02em;
}

.subtitle {
  color: var(--muted);
  font-size: 16px;
}

.btn-back {
  display: inline-block;
  margin-top: 20px;
  text-decoration: none;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.08), rgba(255, 255, 255, 0.03));
  border: 1px solid rgba(255, 255, 255, 0.06);
  color: var(--muted);
  border-radius: 14px;
  font-size: 14px;
  font-weight: 600;
  padding: 10px 20px;
  transition: all 0.2s ease;
}

.btn-back:hover {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.12), rgba(255, 255, 255, 0.06));
  color: var(--text);
  transform: translateY(-1px);
}

section {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.015), rgba(255, 255, 255, 0));
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 32px;
}

h2 {
  margin: 0 0 16px;
  font-size: 24px;
  font-weight: 700;
  color: var(--accent);
  border-bottom: 1px solid var(--line);
  padding-bottom: 8px;
}

h3 {
  font-size: 18px;
  color: var(--accent-2);
  margin-top: 30px;
}

p {
  color: var(--muted);
  margin-bottom: 16px;
}

pre {
  background: #0a0d12;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 20px;
  overflow-x: auto;
  font-size: 14px;
  line-height: 1.5;
}

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, fallback;
  color: #c6d0f5;
}

.block-explain {
  background: rgba(255, 255, 255, 0.03);
  border-left: 4px solid var(--accent);
  padding: 16px 20px;
  margin-bottom: 16px;
  border-radius: 0 12px 12px 0;
}

.block-explain strong {
  display: block;
  color: var(--text);
  margin-bottom: 8px;
  font-size: 16px;
}