/* Chirpy-inspired Theme with Dark/Light Mode Support */
:root {
  --bg-color: #ffffff;
  --text-color: #333333;
  --heading-color: #1a1a1a;
  --link-color: #2a5a8a;
  --link-hover: #1a3a5a;
  --border-color: #e0e0e0;
  --code-bg: #f6f8fa;
  --primary-color: #4a90a4;
  --accent-color: #6a9fb5;
  --card-bg: #ffffff;
  --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

/* Dark Mode Variables */
[data-mode="dark"] {
  --bg-color: #1a1a2e;
  --text-color: #c9c9c9;
  --heading-color: #e0e0e0;
  --link-color: #64b5f6;
  --link-hover: #90caf9;
  --border-color: #3a3a5a;
  --code-bg: #2d2d44;
  --card-bg: #252540;
  --shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

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

body {
  font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  font-size: 16px;
  line-height: 1.8;
  color: var(--text-color);
  background: var(--bg-color);
  transition: background-color 0.3s, color 0.3s;
}

a { color: var(--link-color); text-decoration: none; transition: color 0.3s; }
a:hover { color: var(--link-hover); text-decoration: underline; }
img { max-width: 100%; height: auto; }

/* Header */
.header {
  background: var(--bg-color);
  border-bottom: 1px solid var(--border-color);
  padding: 16px 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow);
  transition: background-color 0.3s, border-color 0.3s;
}

.header__container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.header__brand a {
  font-size: 22px;
  font-weight: 700;
  color: var(--heading-color);
  text-decoration: none;
}

.header__nav {
  display: flex;
  gap: 24px;
  align-items: center;
}

.header__nav a {
  color: var(--text-color);
  font-weight: 500;
  padding: 8px 12px;
  border-radius: 6px;
  transition: all 0.3s;
}

.header__nav a:hover, .header__nav a.active {
  color: var(--primary-color);
  background: rgba(74, 144, 164, 0.1);
  text-decoration: none;
}

/* Dark/Light Toggle Button */
.theme-toggle {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 50%;
  width: 40px;
  height: 40px;
  cursor: pointer;
  font-size: 18px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s;
}

.theme-toggle:hover {
  background: var(--primary-color);
  color: white;
}

/* Main Content */
.main {
  min-height: calc(100vh - 200px);
  padding: 40px 0;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Page Layout */
.page {
  max-width: 900px;
  margin: 0 auto;
}

.page__header {
  text-align: center;
  margin-bottom: 48px;
  padding-bottom: 32px;
  border-bottom: 2px solid var(--primary-color);
}

.page__title {
  font-size: 36px;
  color: var(--heading-color);
  margin-bottom: 16px;
  transition: color 0.3s;
}

.page__desc {
  font-size: 18px;
  color: var(--text-color);
  opacity: 0.8;
}

.page__content h1 { font-size: 28px; margin: 40px 0 20px; color: var(--heading-color); }
.page__content h2 { font-size: 24px; margin: 32px 0 16px; color: var(--heading-color); border-left: 4px solid var(--primary-color); padding-left: 16px; }
.page__content h3 { font-size: 20px; margin: 24px 0 12px; color: var(--heading-color); }
.page__content p { margin-bottom: 16px; }
.page__content ul, .page__content ol { margin: 16px 0; padding-left: 24px; }
.page__content li { margin-bottom: 8px; }
.page__content blockquote {
  border-left: 4px solid var(--primary-color);
  padding: 12px 20px;
  margin: 20px 0;
  background: var(--code-bg);
  font-style: italic;
  border-radius: 0 8px 8px 0;
}
.page__content pre {
  background: var(--code-bg);
  padding: 16px;
  border-radius: 8px;
  overflow-x: auto;
  margin: 20px 0;
  border: 1px solid var(--border-color);
}
.page__content code {
  font-family: 'JetBrains Mono', 'Fira Code', monospace;
  font-size: 14px;
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 4px;
}
.page__content pre code { background: none; padding: 0; }
.page__content table { width: 100%; border-collapse: collapse; margin: 20px 0; }
.page__content th, .page__content td { border: 1px solid var(--border-color); padding: 10px 16px; text-align: left; }
.page__content th { background: var(--code-bg); font-weight: 600; }
.page__content img { border-radius: 8px; margin: 16px 0; box-shadow: var(--shadow); }

/* Home Layout */
.home {
  max-width: 900px;
  margin: 0 auto;
}

.home__header {
  text-align: center;
  padding: 60px 0;
  background: linear-gradient(135deg, var(--primary-color) 0%, var(--accent-color) 100%);
  color: white;
  border-radius: 16px;
  margin-bottom: 48px;
  box-shadow: var(--shadow);
}

.home__title {
  font-size: 42px;
  margin-bottom: 16px;
  color: white;
}

.home__desc {
  font-size: 20px;
  opacity: 0.95;
}

.home__content h2 {
  font-size: 26px;
  margin: 40px 0 20px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--primary-color);
  color: var(--heading-color);
}

.home__content ul {
  list-style: none;
  padding: 0;
}

.home__content li {
  padding: 12px 0;
  border-bottom: 1px solid var(--border-color);
}

.home__content a {
  font-weight: 500;
  font-size: 18px;
}

/* Feature Cards */
.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
  margin: 32px 0;
}

.feature-card {
  padding: 24px;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  background: var(--card-bg);
  transition: transform 0.3s, box-shadow 0.3s, background-color 0.3s;
  box-shadow: var(--shadow);
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.15);
}

.feature-card h3 {
  color: var(--primary-color);
  margin-bottom: 12px;
}

.feature-card p {
  color: var(--text-color);
  font-size: 14px;
  opacity: 0.8;
}

/* Footer */
.footer {
  border-top: 1px solid var(--border-color);
  padding: 40px 0;
  text-align: center;
  color: var(--text-color);
  font-size: 14px;
  margin-top: 60px;
  opacity: 0.7;
  transition: all 0.3s;
}

.footer__container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.footer a { color: var(--primary-color); }

/* Responsive */
@media (max-width: 768px) {
  .header__container { flex-direction: column; gap: 16px; }
  .header__nav { flex-wrap: wrap; justify-content: center; gap: 16px; }
  .home__header { padding: 40px 20px; }
  .home__title { font-size: 28px; }
  .page__title { font-size: 28px; }
  .features { grid-template-columns: 1fr; }
}