:root {
  --bg: #ffffff;
  --text: #1a1a1c;
  --muted: #5d5d63;
  --accent: #284EEA;
  --accent-soft: rgba(40, 78, 234, 0.08);
  --card: #f5f6f8;
  --border: #e6e7eb;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0c0d10;
    --text: #ececef;
    --muted: #9a9aa3;
    --accent: #8aa1ff;
    --accent-soft: rgba(138, 161, 255, 0.10);
    --card: #17181c;
    --border: #25262c;
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  margin: 0;
  padding: 0;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 720px;
  margin: 0 auto;
  padding: 56px 24px 80px;
}

header {
  text-align: center;
  margin-bottom: 40px;
}

.back-link {
  display: inline-block;
  margin-bottom: 16px;
  color: var(--accent);
  text-decoration: none;
  font-size: 0.95rem;
}

.back-link:hover { text-decoration: underline; }

.icon-mark {
  width: 96px;
  height: 96px;
  border-radius: 22px;
  background: linear-gradient(135deg, #3a5cd9 0%, #6c8aff 100%);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  box-shadow: 0 8px 24px rgba(40, 78, 234, 0.25);
}

.icon-mark svg { width: 52px; height: 52px; }

h1 {
  font-size: 2.2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0 0 6px;
}

h2 {
  font-size: 1.3rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin: 36px 0 10px;
}

h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin: 24px 0 6px;
}

.tagline {
  color: var(--muted);
  font-size: 1.05rem;
  margin: 0;
}

.effective {
  color: var(--muted);
  font-size: 0.9rem;
  margin: 0;
}

p, ul { margin: 10px 0; }

ul { padding-left: 22px; }

li { margin: 4px 0; }

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover { text-decoration: underline; }

.lead {
  font-size: 1.08rem;
  color: var(--text);
}

.callout {
  background: var(--accent-soft);
  border-left: 3px solid var(--accent);
  padding: 14px 18px;
  border-radius: 8px;
  margin: 20px 0;
}

.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 14px;
  margin: 28px 0 0;
}

.feature {
  background: var(--card);
  padding: 20px;
  border-radius: 12px;
  border: 1px solid var(--border);
}

.feature h3 {
  margin: 0 0 6px;
  font-size: 1rem;
}

.feature p {
  margin: 0;
  color: var(--muted);
  font-size: 0.93rem;
}

nav.page-nav {
  text-align: center;
  margin: 52px 0 0;
  padding-top: 28px;
  border-top: 1px solid var(--border);
}

nav.page-nav a {
  margin: 0 14px;
  font-weight: 500;
}

footer {
  margin-top: 36px;
  text-align: center;
  color: var(--muted);
  font-size: 0.82rem;
}

footer p { margin: 6px 0; }

.disclaimer { font-size: 0.78rem; }