:root {
  --bg:        #f8fafc;
  --bg-card:   #ffffff;
  --bg-hover:  #f1f5f9;
  --border:    #e2e8f0;
  --text:      #0f172a;
  --text-dim:  #64748b;
  --primary:   #2563eb;
  --primary-h: #1d4ed8;
  --danger:    #ef4444;
  --success:   #10b981;
  --warning:   #f59e0b;
  --radius:    10px;
  --shadow:    0 2px 10px rgba(0, 0, 0, 0.04), 0 1px 3px rgba(0, 0, 0, 0.06);
  --shadow-hover: 0 10px 24px -4px rgba(0, 0, 0, 0.08), 0 4px 12px -2px rgba(0, 0, 0, 0.04);
}

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

body {
  background-color: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a {
  color: inherit;
  text-decoration: none;
}

button, input, select, textarea {
  font-family: inherit;
  color: inherit;
}

/* 顶部导航 */
.site-header {
  background-color: var(--bg-card);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.02);
}

.header-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.logo-area {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.02em;
}

.logo-area img {
  display: block;
}

.search-box {
  flex: 1;
  max-width: 520px;
  position: relative;
}

.search-box form {
  display: flex;
  align-items: center;
  background-color: #f1f5f9;
  border: 1px solid transparent;
  border-radius: var(--radius);
  overflow: hidden;
  transition: all 0.2s ease;
}

.search-box form:focus-within {
  background-color: #ffffff;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.search-input {
  flex: 1;
  background: transparent;
  border: none;
  padding: 10px 14px;
  color: var(--text);
  font-size: 0.92rem;
  outline: none;
}

.search-input::placeholder {
  color: #94a3b8;
}

.search-btn {
  background: transparent;
  border: none;
  padding: 10px 16px;
  color: var(--text-dim);
  cursor: pointer;
  transition: color 0.2s ease;
}

.search-btn:hover {
  color: var(--primary);
}

/* 主容器 */
.main-container {
  max-width: 1280px;
  width: 100%;
  margin: 0 auto;
  padding: 28px 20px;
  flex: 1;
}

/* 面包屑导航栏 */
.breadcrumb-bar {
  margin-bottom: 20px;
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px 20px;
  box-shadow: var(--shadow);
}

.breadcrumb-inner {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
  font-size: 0.95rem;
}

.breadcrumb-icon {
  font-size: 1.1rem;
}

.breadcrumb-separator {
  color: #cbd5e1;
}

.breadcrumb-link {
  color: var(--primary);
  font-weight: 500;
  transition: color 0.2s;
}

.breadcrumb-link:hover {
  color: var(--primary-h);
  text-decoration: underline;
}

.breadcrumb-current {
  color: var(--text);
  font-weight: 600;
}

/* 目录卡片展示区 */
.folder-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 16px;
  margin-bottom: 24px;
}

.folder-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 18px;
  display: flex;
  align-items: center;
  gap: 12px;
  box-shadow: var(--shadow);
  transition: all 0.2s ease;
}

.folder-card:hover {
  transform: translateY(-2px);
  border-color: var(--primary);
  box-shadow: var(--shadow-hover);
  background-color: #f8fafc;
}

.folder-card-icon {
  font-size: 2rem;
  line-height: 1;
}

.folder-card-info {
  display: flex;
  flex-direction: column;
  flex: 1;
  overflow: hidden;
}

.folder-card-name {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.folder-card:hover .folder-card-name {
  color: var(--primary);
}

.folder-card-meta {
  font-size: 0.78rem;
  color: var(--text-dim);
}

.folder-card-arrow {
  color: #cbd5e1;
  font-size: 1.1rem;
  transition: transform 0.2s, color 0.2s;
}

.folder-card:hover .folder-card-arrow {
  transform: translateX(3px);
  color: var(--primary);
}

/* 过滤栏与工具条 */
.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 24px;
  padding: 14px 20px;
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.filters {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.filter-group {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.9rem;
  color: var(--text-dim);
}

.custom-select {
  background-color: #f8fafc;
  border: 1px solid var(--border);
  color: var(--text);
  padding: 6px 14px;
  border-radius: 6px;
  font-size: 0.9rem;
  cursor: pointer;
  outline: none;
  transition: border-color 0.2s;
}

.custom-select:focus {
  border-color: var(--primary);
  background-color: #ffffff;
}

.total-count {
  font-size: 0.9rem;
  color: var(--text-dim);
  font-weight: 500;
}

/* 文件网格卡片 */
.file-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 20px;
  margin-bottom: 32px;
}

.file-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: all 0.25s ease;
  position: relative;
  box-shadow: var(--shadow);
}

.file-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
  border-color: #cbd5e1;
}

/* 卡片预览区域 */
.card-preview {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  background-color: #f1f5f9;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}

.card-preview img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  transition: transform 0.3s ease;
}

.file-card:hover .card-preview img {
  transform: scale(1.03);
}

/* 通用文件专属大图标预览块 */
.file-icon-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, #f8fafc 0%, #edf2f7 100%);
  user-select: none;
}

.file-icon-symbol {
  font-size: 3rem;
  line-height: 1;
}

.file-ext-tag {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 2px 10px;
  border-radius: 4px;
}

.duration-badge {
  position: absolute;
  bottom: 8px;
  right: 8px;
  background-color: rgba(15, 23, 42, 0.75);
  color: #fff;
  font-size: 0.75rem;
  padding: 2px 6px;
  border-radius: 4px;
  font-weight: 500;
}

.category-badge {
  position: absolute;
  top: 8px;
  left: 8px;
  background-color: rgba(37, 99, 235, 0.9);
  color: #fff;
  font-size: 0.75rem;
  padding: 2px 8px;
  border-radius: 4px;
  font-weight: 500;
}

.card-body {
  padding: 16px;
  display: flex;
  flex-direction: column;
  flex: 1;
}

.card-title {
  font-size: 0.95rem;
  font-weight: 600;
  line-height: 1.45;
  margin-bottom: 12px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  color: var(--text);
  word-break: break-all;
}

.file-card:hover .card-title {
  color: var(--primary);
}

.card-meta {
  margin-top: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.82rem;
  color: var(--text-dim);
}

.meta-stats {
  display: flex;
  align-items: center;
  gap: 10px;
}

/* 分页 */
.pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  margin-top: 36px;
  flex-wrap: wrap;
}

.page-item {
  padding: 8px 14px;
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  font-size: 0.9rem;
  transition: all 0.2s ease;
  min-width: 38px;
  text-align: center;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.03);
}

.page-item:hover:not(.disabled):not(.active) {
  background-color: var(--bg-hover);
  border-color: var(--primary);
  color: var(--primary);
}

.page-item.active {
  background-color: var(--primary);
  border-color: var(--primary);
  color: #fff;
  font-weight: 600;
}

.page-item.disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

/* 空状态 */
.empty-state {
  text-align: center;
  padding: 80px 20px;
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 24px;
  box-shadow: var(--shadow);
}

.empty-icon {
  font-size: 3.5rem;
  color: var(--text-dim);
  margin-bottom: 16px;
}

.empty-state h3 {
  font-size: 1.25rem;
  margin-bottom: 8px;
  font-weight: 600;
}

.empty-state p {
  color: var(--text-dim);
  font-size: 0.95rem;
}

/* 文件详情页 */
.detail-layout {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.preview-wrapper {
  width: 100%;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  background-color: #0f172a;
}

.preview-wrapper.media-box {
  aspect-ratio: 16 / 9;
  max-height: 700px;
}

.preview-wrapper video {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
}

.preview-wrapper.image-box {
  background-color: #f1f5f9;
  padding: 24px;
  display: flex;
  justify-content: center;
}

.preview-wrapper.image-box img {
  max-width: 100%;
  max-height: 700px;
  object-fit: contain;
  border-radius: 6px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.preview-wrapper.audio-box {
  background: linear-gradient(135deg, #1e293b, #0f172a);
  padding: 40px 24px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
}

.preview-wrapper.audio-box audio {
  width: 100%;
  max-width: 600px;
}

.file-hero-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 40px 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 16px;
  box-shadow: var(--shadow);
  text-align: center;
}

.file-hero-icon {
  font-size: 4.5rem;
  line-height: 1;
}

.file-hero-name {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text);
  word-break: break-all;
  max-width: 800px;
}

.detail-info {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow);
}

.detail-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 20px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 20px;
}

.detail-title {
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1.35;
  flex: 1;
  min-width: 280px;
  word-break: break-all;
  color: var(--text);
}

.btn-download {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background-color: var(--primary);
  color: #fff;
  padding: 12px 24px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.95rem;
  transition: all 0.2s ease;
  border: none;
  cursor: pointer;
  white-space: nowrap;
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.25);
}

.btn-download:hover {
  background-color: var(--primary-h);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.35);
}

.detail-meta-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 20px;
  color: var(--text-dim);
  font-size: 0.9rem;
  margin-bottom: 20px;
}

.detail-desc {
  color: var(--text);
  font-size: 0.95rem;
  line-height: 1.7;
  white-space: pre-wrap;
  word-break: break-all;
  margin-bottom: 20px;
  padding: 16px;
  background-color: #f8fafc;
  border-radius: 8px;
  border: 1px solid var(--border);
}

.detail-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag-item {
  background-color: #f1f5f9;
  border: 1px solid var(--border);
  color: var(--primary);
  padding: 4px 12px;
  border-radius: 14px;
  font-size: 0.85rem;
  font-weight: 500;
}

.tag-item:hover {
  background-color: #e2e8f0;
}

/* 底部 */
.site-footer {
  background-color: var(--bg-card);
  border-top: 1px solid var(--border);
  margin-top: auto;
  text-align: center;
  padding: 24px 20px;
  font-size: 0.85rem;
  color: var(--text-dim);
}

.footer-inner {
  max-width: 1280px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

/* 错误页面 */
.error-box {
  text-align: center;
  padding: 100px 20px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.error-code {
  font-size: 5rem;
  font-weight: 800;
  color: var(--primary);
  line-height: 1;
  margin-bottom: 16px;
}

.error-msg {
  font-size: 1.25rem;
  color: var(--text-dim);
  margin-bottom: 24px;
}

.btn-primary {
  display: inline-block;
  background-color: var(--primary);
  color: #fff;
  padding: 10px 24px;
  border-radius: 6px;
  font-size: 0.95rem;
  font-weight: 600;
  transition: background-color 0.2s;
}

.btn-primary:hover {
  background-color: var(--primary-h);
}

/* 响应式断点 */
@media (max-width: 768px) {
  .header-inner {
    flex-wrap: wrap;
  }
  .search-box {
    max-width: 100%;
    width: 100%;
  }
  .toolbar {
    flex-direction: column;
    align-items: stretch;
  }
  .filters {
    justify-content: space-between;
  }
  .file-grid {
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 14px;
  }
}

@media (max-width: 480px) {
  .file-grid {
    grid-template-columns: 1fr;
  }
  .detail-title {
    font-size: 1.25rem;
  }
  .btn-download {
    width: 100%;
    justify-content: center;
  }
}