:root {
  color-scheme: light dark;
  --bg: #eceff5;
  --surface: #ffffff;
  --text: #171a2c;
  --muted: #5d6275;
  --accent: #4b5cf6;
  --line: #dde1ec;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121520;
    --surface: #1b1f2e;
    --text: #eef0f7;
    --muted: #a3a8bb;
    --accent: #8b96ff;
    --line: #2a2f42;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding-block: 32px 64px;
  padding-inline: 16px;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.6 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

main {
  max-width: 720px;
  margin: 0 auto;
  background: var(--surface);
  border-radius: 20px;
  padding: 28px 24px 36px;
  box-shadow: 0 10px 30px rgba(23, 26, 44, 0.06);
}

header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 8px;
}

.brand {
  font-weight: 800;
  font-size: 18px;
  letter-spacing: -0.02em;
  color: var(--accent);
  text-decoration: none;
}

nav a {
  color: var(--muted);
  font-size: 14px;
  margin-left: 14px;
  text-decoration: none;
}

nav a:hover {
  color: var(--accent);
}

h1 {
  font-size: 30px;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin: 16px 0 4px;
}

.date {
  color: var(--muted);
  font-size: 14px;
  margin: 0 0 24px;
}

h2 {
  font-size: 19px;
  margin: 32px 0 8px;
  letter-spacing: -0.01em;
}

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

ul {
  padding-left: 20px;
}

li + li {
  margin-top: 6px;
}

.summary {
  background: var(--bg);
  border-radius: 14px;
  padding: 14px 18px;
  margin: 8px 0 8px;
}

.summary ul {
  margin: 0;
}

a {
  color: var(--accent);
}

footer {
  max-width: 720px;
  margin: 20px auto 0;
  color: var(--muted);
  font-size: 13px;
  text-align: center;
}