/* ==================== Reset & Base ==================== */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --bg: #faf9f8;
  --bg-alt: #f0efed;
  --text: #1a1a2e;
  --text-secondary: #6b7280;
  --border: #e5e3e0;
  --accent: #4f6ef7;
  --accent-soft: #eef1ff;
  --card-bg: #ffffff;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-hover: 0 10px 25px rgba(0,0,0,0.08), 0 4px 10px rgba(0,0,0,0.04);
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --container: 960px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans SC", "PingFang SC", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", "SF Mono", "Fira Code", monospace;
}

html { scroll-behavior: smooth; }
body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; height: auto; display: block; }
.container { max-width: var(--container); margin: 0 auto; padding: 0 24px; }

/* ==================== Header ==================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(250, 249, 248, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.site-header .container {
  display: flex;
  align-items: center;
  height: 56px;
  gap: 32px;
}
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}
.logo-img {
  height: 40px;
  width: auto;
}
.logo-text {
  font-size: 0.9rem;
  letter-spacing: -0.01em;
}
.nav-links { display: flex; gap: 24px; margin-right: auto; }
.nav-link {
  font-size: 0.9rem;
  color: var(--text-secondary);
  transition: color var(--transition);
  position: relative;
}
.nav-link::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: width var(--transition);
}
.nav-link:hover { color: var(--text); }
.nav-link:hover::after { width: 100%; }

/* ==================== Hero ==================== */
.hero {
  position: relative;
  padding: 80px 0 64px;
  overflow: hidden;
}
.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 600px 400px at 20% 50%, rgba(79, 110, 247, 0.08) 0%, transparent 70%),
    radial-gradient(ellipse 500px 300px at 80% 30%, rgba(16, 185, 129, 0.06) 0%, transparent 70%);
  pointer-events: none;
}
.hero-content {
  position: relative;
  text-align: center;
  z-index: 1;
}
.hero-badge {
  display: inline-block;
  padding: 4px 14px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--accent);
  background: var(--accent-soft);
  border-radius: 100px;
  margin-bottom: 16px;
}
.hero-title {
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 12px;
}
.hero-subtitle {
  font-size: 1.15rem;
  color: var(--text-secondary);
  font-weight: 500;
  margin-bottom: 8px;
}
.hero-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
  max-width: 520px;
  margin: 0 auto;
}

/* ==================== Video Grid ==================== */
.video-grid {
  padding: 40px 0;
}
.video-grid .container {
  max-width: 1440px;
}
.videos {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 16px;
}
.videos video {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border-radius: var(--radius-sm);
  background: #000;
}

/* ==================== Categories ==================== */
.categories {
  padding: 0 0 64px;
}
.categories .container {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.category-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px 24px;
  text-align: center;
  transition: all var(--transition);
  cursor: pointer;
}
.category-card:hover {
  border-color: var(--card-accent);
  box-shadow: var(--shadow-hover);
  transform: translateY(-2px);
}
.category-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 64px;
  height: 64px;
  border-radius: 16px;
  background: color-mix(in srgb, var(--card-accent) 10%, transparent);
  color: var(--card-accent);
  margin-bottom: 16px;
}
.category-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 4px;
}
.category-card p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 12px;
}
.category-count {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--card-accent);
  background: color-mix(in srgb, var(--card-accent) 10%, transparent);
  padding: 2px 12px;
  border-radius: 100px;
}

/* ==================== Sections ==================== */
.section { padding: 64px 0; }
.section-alt { background: var(--bg-alt); }
.section-header { margin-bottom: 32px; }
.section-header h2 {
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 4px;
}
.section-desc { font-size: 0.9rem; color: var(--text-secondary); }

/* ==================== Category Tabs ==================== */
.cat-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}
.cat-tab {
  padding: 6px 16px;
  font-size: 0.85rem;
  font-weight: 500;
  border: 1px solid var(--border);
  border-radius: 100px;
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition);
  font-family: inherit;
}
.cat-tab:hover {
  border-color: var(--accent);
  color: var(--accent);
}
.cat-tab.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

/* 二级标签 */
.cat-sub-tabs {
  margin-top: -12px;
  margin-bottom: 20px;
  padding-left: 4px;
}
.cat-sub-tabs .cat-tab {
  font-size: 0.8rem;
  padding: 4px 12px;
  background: transparent;
  border-color: transparent;
  color: var(--text-secondary);
}
.cat-sub-tabs .cat-tab:hover {
  color: var(--accent);
  background: var(--accent-soft);
  border-color: var(--accent-soft);
}
.cat-sub-tabs .cat-tab.active {
  background: var(--accent-soft);
  border-color: var(--accent-soft);
  color: var(--accent);
  font-weight: 600;
}

/* ==================== File List ==================== */
.file-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.file-item {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 12px 20px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  transition: all var(--transition);
}
.file-item:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow-hover);
}
.file-info-link {
  display: flex;
  align-items: center;
  gap: 16px;
  flex: 1;
  min-width: 0;
  color: inherit;
  text-decoration: none;
  cursor: pointer;
}
.file-icon {
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 10px;
  font-size: 1.2rem;
}
.file-info { flex: 1; min-width: 0; }
.file-name {
  font-weight: 600;
  font-size: 0.95rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.file-meta {
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-top: 2px;
}
.file-size {
  flex-shrink: 0;
  font-size: 0.8rem;
  font-family: var(--font-mono);
  color: var(--text-secondary);
}
.file-actions {
  display: flex;
  gap: 8px;
  flex-shrink: 0;
}
.file-btn {
  padding: 6px 14px;
  font-size: 0.85rem;
  font-weight: 600;
  font-family: inherit;
  border-radius: 100px;
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  border: none;
}
.read-btn {
  color: var(--accent);
  background: var(--accent-soft);
}
.read-btn:hover {
  background: var(--accent);
  color: #fff;
}
.download-btn {
  color: var(--text-secondary);
  background: transparent;
  border: 1px solid var(--border);
}
.download-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-soft);
}
.file-item:hover .download-btn {
  border-color: var(--accent);
}

/* ==================== Image Grid ==================== */
.image-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 16px;
}
.image-card {
  position: relative;
  aspect-ratio: 4 / 3;
  border-radius: var(--radius-sm);
  overflow: hidden;
  background: var(--card-bg);
  border: 1px solid var(--border);
  cursor: pointer;
  transition: all var(--transition);
}
.image-card:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow-hover);
  transform: translateY(-2px);
}
.image-card img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.image-card .image-overlay {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 12px;
  background: linear-gradient(transparent, rgba(0,0,0,0.65));
  color: #fff;
  font-size: 0.85rem;
  font-weight: 500;
  opacity: 0;
  transition: opacity var(--transition);
}
.image-card:hover .image-overlay { opacity: 1; }

/* ==================== Lightbox ==================== */
.lightbox {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 999;
  background: rgba(0,0,0,0.85);
  backdrop-filter: blur(8px);
  align-items: center;
  justify-content: center;
  padding: 40px;
}
.lightbox.active { display: flex; }
.lightbox img {
  max-width: 90vw;
  max-height: 85vh;
  object-fit: contain;
  border-radius: var(--radius-sm);
}
.lightbox-close {
  position: absolute;
  top: 20px;
  right: 24px;
  font-size: 2rem;
  color: #fff;
  cursor: pointer;
  opacity: 0.7;
  transition: opacity var(--transition);
  background: none;
  border: none;
}
.lightbox-close:hover { opacity: 1; }

/* ==================== Empty State ==================== */
.empty-state {
  text-align: center;
  padding: 48px 24px;
  color: var(--text-secondary);
  font-size: 0.95rem;
  background: var(--card-bg);
  border: 2px dashed var(--border);
  border-radius: var(--radius);
}

/* ==================== Footer ==================== */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 32px 0;
  text-align: center;
}
.site-footer p {
  font-size: 0.9rem;
  color: var(--text-secondary);
}
.footer-meta {
  font-size: 0.8rem;
  margin-top: 4px;
}

/* ==================== Modal ==================== */
.modal-overlay {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 999;
  background: rgba(0,0,0,0.5);
  backdrop-filter: blur(4px);
  align-items: center;
  justify-content: center;
  padding: 24px;
}
.modal-overlay.active { display: flex; }
.modal {
  background: var(--card-bg);
  border-radius: var(--radius);
  max-width: 640px;
  width: 100%;
  max-height: 80vh;
  overflow-y: auto;
  padding: 32px;
  position: relative;
}
.modal-close {
  position: absolute;
  top: 16px;
  right: 20px;
  font-size: 1.5rem;
  color: var(--text-secondary);
  cursor: pointer;
  background: none;
  border: none;
  transition: color var(--transition);
}
.modal-close:hover { color: var(--text); }
.modal-body h1, .modal-body h2, .modal-body h3 { margin-top: 1.5em; margin-bottom: 0.5em; }
.modal-body h1 { font-size: 1.4rem; }
.modal-body h2 { font-size: 1.2rem; }
.modal-body h3 { font-size: 1.05rem; }
.modal-body p { margin-bottom: 1em; color: var(--text-secondary); }
.modal-body ul, .modal-body ol { padding-left: 1.5em; margin-bottom: 1em; }
.modal-body li { margin-bottom: 0.3em; color: var(--text-secondary); }
.modal-body code {
  font-family: var(--font-mono);
  font-size: 0.85em;
  background: var(--bg-alt);
  padding: 2px 6px;
  border-radius: 4px;
}
.modal-body pre {
  background: #1a1a2e;
  color: #e5e3e0;
  padding: 16px;
  border-radius: var(--radius-sm);
  overflow-x: auto;
  margin-bottom: 1em;
}
.modal-body pre code { background: none; padding: 0; color: inherit; }
.modal-body a { color: var(--accent); text-decoration: underline; }
.modal-body blockquote {
  border-left: 3px solid var(--accent);
  padding-left: 16px;
  color: var(--text-secondary);
  margin-bottom: 1em;
}
.modal-body img { margin: 1em 0; border-radius: var(--radius-sm); }

/* ==================== Search ==================== */
.search-box {
  position: relative;
  margin: 0 16px;
}
.search-input {
  width: 180px;
  padding: 6px 14px;
  font-size: 0.85rem;
  font-family: inherit;
  border: 1px solid var(--border);
  border-radius: 100px;
  background: var(--card-bg);
  color: var(--text);
  outline: none;
  transition: all var(--transition);
}
.search-input:focus {
  width: 240px;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(79, 110, 247, 0.1);
}
.search-input::placeholder { color: var(--text-secondary); }
.search-results {
  display: none;
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  width: 360px;
  max-height: 400px;
  overflow-y: auto;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-hover);
  z-index: 200;
}
.search-results.active { display: block; }
.search-result-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 16px;
  cursor: pointer;
  transition: background var(--transition);
  border-bottom: 1px solid var(--border);
}
.search-result-item:last-child { border-bottom: none; }
.search-result-item:hover { background: var(--accent-soft); }
.search-result-icon { font-size: 1rem; flex-shrink: 0; }
.search-result-info { flex: 1; min-width: 0; }
.search-result-name {
  font-size: 0.9rem;
  font-weight: 600;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.search-result-meta {
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-top: 2px;
}
.search-empty {
  padding: 24px;
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.85rem;
}

/* ==================== Account ==================== */
.header-right {
  display: flex;
  align-items: center;
  margin-left: auto;
}
.account-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border-radius: 100px;
  cursor: pointer;
  transition: all var(--transition);
  border: 1px solid transparent;
  user-select: none;
}
.account-btn:hover {
  background: var(--accent-soft);
  border-color: var(--border);
}
.account-icon { font-size: 1.1rem; line-height: 1; }
.account-name {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
}
.account-btn:hover .account-name { color: var(--accent); }

.account-modal {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 999;
  background: rgba(0,0,0,0.4);
  backdrop-filter: blur(4px);
  align-items: center;
  justify-content: center;
  padding: 24px;
}
.account-modal.active { display: flex; }
.account-modal-content {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 32px;
  max-width: 360px;
  width: 100%;
  position: relative;
  text-align: center;
}
.account-modal-close {
  position: absolute;
  top: 12px;
  right: 16px;
  font-size: 1.5rem;
  color: var(--text-secondary);
  cursor: pointer;
  background: none;
  border: none;
  transition: color var(--transition);
}
.account-modal-close:hover { color: var(--text); }
.account-modal-content h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 4px;
}
.account-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 20px;
}
.account-input {
  width: 100%;
  padding: 10px 16px;
  font-size: 0.95rem;
  font-family: inherit;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  outline: none;
  transition: border-color var(--transition);
  margin-bottom: 12px;
  text-align: center;
}
.account-input:focus { border-color: var(--accent); }
.account-error {
  font-size: 0.8rem;
  color: #ef4444;
  margin-bottom: 10px;
  min-height: 1.2em;
}
.account-submit {
  width: 100%;
  padding: 10px 16px;
  font-size: 0.95rem;
  font-weight: 600;
  font-family: inherit;
  border: none;
  border-radius: var(--radius-sm);
  background: var(--accent);
  color: #fff;
  cursor: pointer;
  transition: background var(--transition);
}
.account-submit:hover { background: #3d5bd9; }
.account-logout {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-secondary);
}
.account-logout:hover { border-color: #ef4444; color: #ef4444; background: #fef2f2; }
.profile-avatar {
  font-size: 2.5rem;
  margin-bottom: 8px;
}

/* ==================== Search Highlight ==================== */
.file-item.search-highlight,
.image-card.search-highlight {
  background: var(--accent-soft) !important;
  border-color: var(--accent) !important;
  box-shadow: 0 0 0 3px var(--accent-soft), var(--shadow-hover) !important;
}

/* ==================== Responsive ==================== */
@media (max-width: 768px) {
  .categories .container { grid-template-columns: 1fr; }
  .hero { padding: 48px 0 40px; }
  .section { padding: 40px 0; }
  .image-grid { grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); }
  .file-item { flex-wrap: wrap; }
  .file-size { display: none; }
  .lightbox { padding: 16px; }
  .modal { padding: 24px; }
  .search-box { margin: 0 8px; }
  .search-input { width: 120px; }
  .search-input:focus { width: 160px; }
  .search-results { width: 300px; right: -60px; }
}