* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --bg: #fff;
  --text: #222;
  --text-secondary: #666;
  --border: #ddd;
  --heading: #000;
}

[data-theme="dark"] {
  --bg: #000;
  --text: #e5e5e5;
  --text-secondary: #888;
  --border: #333;
  --heading: #fff;
}

body {
  background-color: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.7;
  min-height: 100vh;
  padding: 40px 20px;
}

.container {
  max-width: 1240px;
  margin: 0 auto;
  padding: 48px 40px;
}

nav {
  display: flex;
  align-items: center;
  gap: 24px;
  margin-bottom: 32px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
  flex-wrap: nowrap;
}

.brand {
  font-size: 15px;
  font-weight: 700;
  color: var(--heading);
  margin-right: 8px;
  white-space: nowrap;
}

nav a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: color 0.2s;
  white-space: nowrap;
}


nav a:hover,
nav a.active {
  color: var(--heading);
}

.theme-toggle {
  margin-left: auto;
  background: none;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 4px 8px;
  cursor: pointer;
  font-size: 16px;
  line-height: 1;
  color: var(--heading);
  transition: border-color 0.2s, color 0.2s;
}

.theme-toggle:hover {
  border-color: var(--text-secondary);
}

h1 {
  font-size: 28px;
  font-weight: 700;
  color: var(--heading);
  margin-bottom: 8px;
}

.updated {
  color: var(--text-secondary);
  font-size: 14px;
  margin-bottom: 32px;
}

h2 {
  font-size: 18px;
  font-weight: 600;
  color: var(--heading);
  margin-top: 32px;
  margin-bottom: 12px;
}

h3 {
  font-size: 15px;
  font-weight: 600;
  color: var(--heading);
  margin-top: 24px;
  margin-bottom: 6px;
}

p {
  color: var(--text);
  font-size: 15px;
  margin-bottom: 12px;
}

ul {
  padding-left: 20px;
  margin-bottom: 12px;
}

li {
  color: var(--text);
  font-size: 15px;
  margin-bottom: 6px;
}

li::marker {
  color: var(--text-secondary);
}

a {
  color: var(--heading);
  text-decoration: underline;
  text-underline-offset: 2px;
}

a:hover {
  color: var(--text-secondary);
}

@media (max-width: 600px) {
  body {
    padding: 20px 12px;
  }

  .container {
    padding: 28px 20px;
  }

  nav {
    gap: 12px;
  }

  .brand {
    font-size: 14px;
    margin-right: 4px;
  }

  nav a {
    font-size: 13px;
  }

  h1 {
    font-size: 24px;
  }
}