:root {
  --bg-top: #e2eeff;
  --bg-bottom: #f8fbff;
  --card: #ffffff;
  --text: #17233d;
  --muted: #68758a;
  --brand: #3478f6;
  --brand-deep: #2161d1;
  --info: #e8f2ff;
  --border: #e9edf3;
  --shadow: 0 12px 32px rgba(23, 35, 61, 0.06);
}

* { box-sizing: border-box; }

html { color-scheme: light; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  line-height: 1.6;
  color: var(--text);
  background: linear-gradient(180deg, var(--bg-top) 0, var(--bg-bottom) 280px);
}

a { color: var(--brand-deep); }

header {
  position: sticky;
  top: 0;
  z-index: 2;
  background: rgba(255, 255, 255, 0.92);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(12px);
}

header .wrap,
footer .wrap {
  max-width: 880px;
  margin: 0 auto;
  padding: 16px 24px;
}

header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  font-weight: 700;
  font-size: 1.05rem;
  text-decoration: none;
}

.mark {
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: var(--brand);
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.25);
  position: relative;
}

.mark::before,
.mark::after {
  content: "";
  position: absolute;
  background: #fff;
  border-radius: 2px;
}

.mark::before {
  width: 10px;
  height: 2px;
  left: 9px;
  top: 13px;
}

.mark::after {
  width: 2px;
  height: 10px;
  left: 13px;
  top: 9px;
}

nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

nav a {
  color: var(--brand-deep);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.92rem;
  padding: 6px 10px;
  border-radius: 999px;
  background: var(--info);
}

nav a[aria-current="page"] {
  background: var(--brand);
  color: #fff;
}

main {
  max-width: 880px;
  margin: 20px auto 40px;
  padding: 28px 28px 36px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 20px;
  box-shadow: var(--shadow);
}

h1 {
  font-size: 2rem;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin: 0 0 8px;
}

h2 {
  font-size: 1.2rem;
  margin: 32px 0 10px;
}

h3 {
  font-size: 1.02rem;
  margin: 20px 0 8px;
}

p, li { color: var(--text); }

.lede, .meta, footer { color: var(--muted); }

.meta { margin: 0 0 8px; }

.callout {
  margin: 20px 0 8px;
  padding: 14px 16px;
  border-radius: 14px;
  background: var(--info);
  color: var(--brand-deep);
}

.grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 8px;
}

.card {
  margin: 0;
  padding: 16px;
  border: 1px solid var(--border);
  border-radius: 16px;
  background: #fff;
}

.card h3 { margin-top: 0; }

.card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.actions { margin-top: 8px; }

.cta {
  display: inline-block;
  margin: 8px 8px 0 0;
  padding: 10px 14px;
  border-radius: 12px;
  background: var(--brand);
  color: #fff;
  text-decoration: none;
  font-weight: 650;
}

.cta.secondary {
  background: var(--info);
  color: var(--brand-deep);
}

ul { padding-left: 1.2rem; }

footer {
  font-size: 0.92rem;
  padding-bottom: 28px;
}

@media (max-width: 680px) {
  header .wrap { align-items: flex-start; flex-direction: column; }
  main { margin: 12px; padding: 22px 18px 28px; }
  .grid { grid-template-columns: 1fr; }
  h1 { font-size: 1.7rem; }
}