:root {
  --indigo: #313c9e;
  --indigo-dark: #1a1f4b;
  --blue: #2563eb;
  --ink: #0f172a;
  --muted: #5b6478;
  --line: #e6e8ef;
  --bg: #f7f8fc;
  --card: #ffffff;
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

.wrap { max-width: 720px; margin: 0 auto; padding: 0 20px; }

/* Header / hero */
.hero {
  /* Light band so the dark, colorful app icon stands out (a dark banner sat too close
     to the icon's near-black background). */
  background: linear-gradient(180deg, #f1f4fb 0%, #e3e8f6 100%);
  border-bottom: 1px solid var(--line);
  color: var(--ink);
  text-align: center;
  padding: 64px 20px 56px;
}
.hero img.icon {
  width: 120px; height: 120px;
  border-radius: 27%;
  box-shadow: 0 12px 30px rgba(26, 31, 75, .28);
}
.hero h1 { font-size: 2.4rem; margin: 20px 0 6px; letter-spacing: -.02em; }
.hero p.tagline { font-size: 1.15rem; margin: 0; color: var(--muted); }

/* Buttons */
.buttons { margin-top: 28px; display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }
.btn {
  display: inline-block;
  padding: 12px 22px;
  border-radius: 12px;
  font-weight: 600;
  font-size: .98rem;
}
.btn-primary { background: var(--indigo); color: #fff; }
.btn-primary:hover { background: var(--indigo-dark); text-decoration: none; }
.btn-ghost { background: #fff; color: var(--ink); border: 1px solid #cdd3e4; }
.btn-ghost:hover { background: #fbfcff; text-decoration: none; }

/* Content */
main { padding: 48px 0 24px; }
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 28px 28px 8px;
  margin-bottom: 24px;
}
h2 { font-size: 1.35rem; margin: 28px 0 10px; letter-spacing: -.01em; }
h3 { font-size: 1.05rem; margin: 22px 0 6px; }
.lead { font-size: 1.1rem; color: var(--ink); }
.muted { color: var(--muted); }
ul { padding-left: 1.2em; }
li { margin: 6px 0; }
code { background: #f0f2f8; padding: 2px 6px; border-radius: 6px; font-size: .9em; }

/* Page title (subpages) */
.page-head { padding: 40px 0 8px; }
.page-head h1 { margin: 0 0 4px; font-size: 1.9rem; letter-spacing: -.02em; }
.page-head .back { font-size: .95rem; }

/* Footer */
footer {
  border-top: 1px solid var(--line);
  padding: 28px 0 48px;
  color: var(--muted);
  font-size: .9rem;
  text-align: center;
}
footer a { color: var(--muted); text-decoration: underline; }
footer .row { margin: 4px 0; }