/* ============================================
   clkcb.com - 技术博客样式
   移动优先响应式设计
   ============================================ */

/* --- CSS 变量 --- */
:root {
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: #dbeafe;
  --bg: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-code: #1e293b;
  --text: #1e293b;
  --text-secondary: #64748b;
  --text-light: #94a3b8;
  --border: #e2e8f0;
  --card-shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
  --card-shadow-hover: 0 10px 25px rgba(0,0,0,0.1);
  --radius: 12px;
  --radius-sm: 8px;
  --max-width: 800px;
  --header-height: 60px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Fira Mono", "Source Code Pro", Consolas, "Liberation Mono", Menlo, monospace;
}

/* --- Reset --- */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  min-height: 100vh;
}
a { color: var(--primary); text-decoration: none; }
a:hover { color: var(--primary-hover); text-decoration: underline; }
img { max-width: 100%; height: auto; display: block; }

/* --- Header --- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  height: var(--header-height);
}
.header-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 20px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.logo {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 8px;
}
.logo:hover { text-decoration: none; color: var(--primary); }
.logo .logo-dot { color: var(--primary); font-size: 1.6rem; line-height: 1; }
.nav-links {
  display: flex;
  align-items: center;
  gap: 24px;
  list-style: none;
}
.nav-links a {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 6px 0;
  border-bottom: 2px solid transparent;
  transition: color 0.2s, border-color 0.2s;
}
.nav-links a:hover, .nav-links a.active {
  color: var(--primary);
  text-decoration: none;
  border-bottom-color: var(--primary);
}
.menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text);
  padding: 4px;
}

/* --- Main --- */
main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 32px 20px 60px;
  min-height: calc(100vh - var(--header-height));
}
.page-title { font-size: 2rem; font-weight: 800; margin-bottom: 8px; line-height: 1.3; }
.page-subtitle { color: var(--text-secondary); font-size: 1.05rem; margin-bottom: 40px; }
.section-title {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 8px;
}

/* --- Cards --- */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 20px;
  margin-bottom: 48px;
}
.card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--card-shadow);
  transition: box-shadow 0.25s, transform 0.25s;
}
.card:hover {
  box-shadow: var(--card-shadow-hover);
  transform: translateY(-2px);
}
.card-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 2px 10px;
  border-radius: 20px;
  margin-bottom: 12px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.card-tag.article { background: var(--primary-light); color: var(--primary); }
.card-tag.video { background: #fef3c7; color: #d97706; }
.card-title { font-size: 1.15rem; font-weight: 700; line-height: 1.4; margin-bottom: 8px; }
.card-title a { color: var(--text); }
.card-title a:hover { color: var(--primary); text-decoration: none; }
.card-meta { font-size: 0.85rem; color: var(--text-light); margin-bottom: 10px; }
.card-summary {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.6;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.card-video-preview {
  width: 100%;
  aspect-ratio: 16 / 9;
  background: var(--bg-code);
  border-radius: var(--radius-sm);
  margin-bottom: 14px;
  overflow: hidden;
  position: relative;
}
.card-video-preview iframe, .card-video-preview img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.card-video-preview .play-icon {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3rem;
  color: white;
  background: rgba(0,0,0,0.3);
  transition: background 0.2s;
}
.card-video-preview:hover .play-icon { background: rgba(0,0,0,0.5); }

/* --- Article --- */
.article-content { max-width: var(--max-width); margin: 0 auto; }
.article-header { margin-bottom: 32px; padding-bottom: 24px; border-bottom: 1px solid var(--border); }
.article-header .card-tag { margin-bottom: 16px; }
.article-header h1 { font-size: 2.2rem; font-weight: 800; line-height: 1.3; margin-bottom: 12px; }
.article-meta { display: flex; flex-wrap: wrap; gap: 16px; font-size: 0.88rem; color: var(--text-secondary); }
.article-body { font-size: 1.05rem; line-height: 1.85; }
.article-body h2 { font-size: 1.6rem; font-weight: 700; margin: 36px 0 16px; padding-bottom: 8px; border-bottom: 1px solid var(--border); }
.article-body h3 { font-size: 1.25rem; font-weight: 600; margin: 28px 0 12px; }
.article-body p { margin-bottom: 20px; }
.article-body ul, .article-body ol { margin: 0 0 20px 24px; }
.article-body li { margin-bottom: 8px; }
.article-body code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--bg-secondary);
  padding: 2px 8px;
  border-radius: 4px;
  border: 1px solid var(--border);
}
.article-body pre {
  background: var(--bg-code);
  color: #e2e8f0;
  padding: 20px;
  border-radius: var(--radius-sm);
  overflow-x: auto;
  margin: 24px 0;
  font-size: 0.92rem;
  line-height: 1.6;
}
.article-body pre code { background: none; border: none; padding: 0; color: inherit; }
.article-body blockquote {
  border-left: 4px solid var(--primary);
  padding: 12px 20px;
  margin: 24px 0;
  background: var(--bg-secondary);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--text-secondary);
}
.article-body blockquote p:last-child { margin-bottom: 0; }
.article-body a { word-break: break-all; }

/* --- Video --- */
.video-container { max-width: var(--max-width); margin: 0 auto; }
.video-player-wrapper {
  width: 100%;
  aspect-ratio: 16 / 9;
  background: #000;
  border-radius: var(--radius);
  overflow: hidden;
  margin-bottom: 24px;
}
.video-player-wrapper iframe { width: 100%; height: 100%; border: none; }
.video-header h1 { font-size: 1.6rem; font-weight: 800; margin-bottom: 8px; }

/* --- Search --- */
.search-box { position: relative; margin-bottom: 32px; }
.search-box input {
  width: 100%;
  padding: 14px 20px 14px 48px;
  font-size: 1.05rem;
  border: 2px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg);
  color: var(--text);
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
  font-family: var(--font-sans);
}
.search-box input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-light);
}
.search-box .search-icon {
  position: absolute;
  left: 16px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.2rem;
  color: var(--text-light);
  pointer-events: none;
}
.search-stats { font-size: 0.88rem; color: var(--text-secondary); margin-bottom: 20px; }
.search-results .card { margin-bottom: 16px; }
.search-empty {
  text-align: center;
  padding: 60px 20px;
  color: var(--text-light);
}
.search-empty .empty-icon { font-size: 3rem; margin-bottom: 16px; }
.search-empty p { font-size: 1.1rem; }
.search-highlight { background: #fef08a; padding: 0 2px; border-radius: 2px; }

/* --- About --- */
.about-page { max-width: var(--max-width); margin: 0 auto; }
.about-page .avatar {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  background: var(--primary-light);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
  color: var(--primary);
  margin-bottom: 24px;
}
.about-page h1 { font-size: 2rem; font-weight: 800; margin-bottom: 8px; }
.about-page .bio { color: var(--text-secondary); font-size: 1.05rem; line-height: 1.8; margin-bottom: 32px; }
.about-section { margin-bottom: 32px; }
.about-section h2 { font-size: 1.2rem; font-weight: 700; margin-bottom: 12px; }
.about-section ul { list-style: none; }
.about-section li {
  padding: 8px 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.95rem;
  color: var(--text-secondary);
}
.about-section li:last-child { border-bottom: none; }
.about-section li strong { color: var(--text); }

/* --- Footer --- */
.site-footer {
  text-align: center;
  padding: 32px 20px;
  font-size: 0.85rem;
  color: var(--text-light);
  border-top: 1px solid var(--border);
}

/* --- Back to Top --- */
.back-top {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--primary);
  color: white;
  border: none;
  font-size: 1.2rem;
  cursor: pointer;
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.3s, transform 0.3s;
  z-index: 90;
}
.back-top.visible { opacity: 1; transform: translateY(0); }
.back-top:hover { background: var(--primary-hover); }

/* ============================================
   响应式 - 平板
   ============================================ */
@media (max-width: 768px) {
  .header-inner { padding: 0 16px; }
  .nav-links {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--bg);
    flex-direction: column;
    padding: 16px;
    gap: 4px;
    border-bottom: 1px solid var(--border);
    box-shadow: var(--card-shadow);
  }
  .nav-links.open { display: flex; }
  .nav-links a {
    display: block;
    padding: 12px 16px;
    border-radius: var(--radius-sm);
    border-bottom: none;
    font-size: 1rem;
  }
  .nav-links a:hover, .nav-links a.active { background: var(--bg-secondary); border-bottom: none; }
  .menu-toggle { display: block; }
  main { padding: 24px 16px 40px; }
  .page-title { font-size: 1.6rem; }
  .page-subtitle { font-size: 0.95rem; margin-bottom: 28px; }
  .card-grid { grid-template-columns: 1fr; gap: 16px; }
  .article-header h1 { font-size: 1.5rem; }
  .article-body { font-size: 1rem; }
  .article-body h2 { font-size: 1.3rem; }
  .article-body h3 { font-size: 1.1rem; }
  .article-body pre { padding: 14px; font-size: 0.85rem; }
  .video-header h1 { font-size: 1.3rem; }
  .about-page h1 { font-size: 1.6rem; }
}

/* ============================================
   响应式 - 手机小屏
   ============================================ */
@media (max-width: 480px) {
  .card { padding: 18px; }
  .card-grid { gap: 12px; }
  .card-title { font-size: 1.05rem; }
  .article-header h1 { font-size: 1.3rem; }
  .article-body h2 { font-size: 1.15rem; }
  .search-box input { padding: 12px 16px 12px 42px; font-size: 1rem; }
}