/* ============================================
   UI Components
   ============================================ */

/* --- Back to Top --- */
.back-to-top {
  position: fixed;
  right: 24px;
  bottom: 32px;
  width: 44px;
  height: 44px;
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: var(--shadow-card);
  transition: all var(--transition-normal);
  opacity: 0;
  visibility: hidden;
  z-index: 100;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-card-hover);
  border-color: var(--accent-fire);
}

.back-to-top svg {
  width: 20px;
  height: 20px;
  fill: var(--text-secondary);
  transition: fill var(--transition-fast);
}

.back-to-top:hover svg {
  fill: var(--accent-fire);
}

/* --- Mobile Sidebar Toggle --- */
.sidebar-toggle {
  display: none;
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 200;
  width: 40px;
  height: 40px;
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  cursor: pointer;
  box-shadow: var(--shadow-card);
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

.sidebar-toggle:hover {
  border-color: var(--accent-fire);
}

.sidebar-toggle svg {
  width: 20px;
  height: 20px;
  fill: var(--text-primary);
}

.sidebar-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.3);
  z-index: 150;
}

/* --- Loading --- */
.loading {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 80px 0;
  flex-direction: column;
  gap: 16px;
}

.loading-spinner {
  width: 36px;
  height: 36px;
  border: 3px solid var(--border-light);
  border-top-color: var(--accent-fire);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* --- Search Box --- */
.sidebar-search {
  padding: 0 16px 12px;
  border-bottom: 1px solid var(--border-light);
  margin-bottom: 8px;
}

.sidebar-search input {
  width: 100%;
  padding: 8px 12px;
  border: 1px solid var(--border-light);
  border-radius: 20px;
  font-size: 13px;
  outline: none;
  background: var(--bg-page);
  color: var(--text-primary);
  transition: border-color var(--transition-fast), background var(--transition-fast);
}

.sidebar-search input::placeholder {
  color: var(--text-secondary);
}

.sidebar-search input:focus {
  border-color: var(--accent-fire);
}

.toc-item.hidden {
  display: none;
}

/* --- 搜索无结果提示 --- */
.toc-no-results {
  padding: 16px;
  text-align: center;
  color: var(--text-secondary);
  font-size: 13px;
  display: none;
}

.toc-no-results.visible {
  display: block;
}

/* --- 版本更新摘要 --- */
.update-summary {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 10px;
  margin: 16px 0 18px;
}

.update-summary-item {
  padding: 12px 14px;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  background: var(--bg-page);
}

.update-summary-item h4 {
  margin: 0 0 6px;
  color: var(--text-primary);
  font-size: 15px;
  line-height: 1.4;
}

.update-summary-item p {
  margin: 0;
  color: var(--text-primary);
  font-size: 13.5px;
  line-height: 1.65;
}

.update-summary-item span {
  display: block;
  margin-top: 8px;
  color: var(--accent-gold);
  font-size: 12.5px;
  font-weight: 600;
}

/* --- 35重劫运单条查询器 --- */
.jieyun-lookup {
  margin: 18px 0 24px;
  padding: 18px;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  background: var(--bg-page);
}

.jieyun-lookup-controls {
  display: grid;
  gap: 10px;
}

.jieyun-lookup-label {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-primary);
}

.jieyun-lookup-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 10px;
}

.jieyun-lookup-input {
  width: 100%;
  min-width: 0;
  padding: 10px 12px;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  background: var(--bg-card);
  color: var(--text-primary);
  font: inherit;
  font-size: 14px;
  outline: none;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.jieyun-lookup-input:focus {
  border-color: var(--accent-fire);
  box-shadow: 0 0 0 3px rgba(var(--accent-fire-rgb), 0.12);
}

.jieyun-lookup-button {
  padding: 10px 18px;
  border: 1px solid var(--accent-fire);
  border-radius: var(--radius-sm);
  background: var(--accent-fire);
  color: #fff;
  font: inherit;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition-fast), border-color var(--transition-fast);
}

.jieyun-lookup-button:hover {
  background: var(--accent-fire-hover);
  border-color: var(--accent-fire-hover);
}

.jieyun-lookup-result {
  margin-top: 14px;
}

.jieyun-lookup-empty {
  margin: 0;
  color: var(--text-secondary);
  font-size: 14px;
}

.jieyun-card {
  padding: 14px 16px;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  background: var(--bg-card);
}

.jieyun-card-kicker {
  color: var(--accent-gold);
  font-size: 13px;
  font-weight: 600;
}

.jieyun-card h2 {
  margin: 6px 0 10px;
  padding: 0;
  border: 0;
  font-size: 20px;
}

.jieyun-card blockquote {
  margin: 10px 0;
}

.jieyun-card p {
  margin-bottom: 0;
}

.jieyun-lookup-index {
  display: none;
}

/* --- 阅读进度条 --- */
.read-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 0%;
  height: 3px;
  background: linear-gradient(90deg, var(--accent-fire), var(--accent-gold));
  z-index: 9999;
  transition: width 0.1s linear;
}

/* --- 代码复制按钮 --- */
.copy-btn {
  position: absolute;
  top: 8px;
  right: 8px;
  padding: 4px 10px;
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-sm);
  color: #abb2bf;
  font-size: 12px;
  cursor: pointer;
  opacity: 0;
  transition: opacity var(--transition-fast), background var(--transition-fast), color var(--transition-fast);
  font-family: inherit;
  line-height: 1.5;
}

.md-body pre:hover .copy-btn,
.copy-btn:focus {
  opacity: 1;
}

.copy-btn:hover {
  background: rgba(255, 255, 255, 0.2);
  color: #fff;
}

.copy-btn.copied {
  color: #98c379;
  border-color: rgba(152, 195, 121, 0.4);
}

/* --- 主题切换按钮 --- */
.theme-toggle {
  position: fixed;
  top: 12px;
  right: 12px;
  z-index: 200;
  width: 40px;
  height: 40px;
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: 50%;
  cursor: pointer;
  box-shadow: var(--shadow-card);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
  color: var(--text-primary);
}

.theme-toggle:hover {
  border-color: var(--accent-fire);
  transform: scale(1.05);
}

.theme-toggle svg {
  width: 20px;
  height: 20px;
  fill: currentColor;
}

/* 移动端适配主题按钮位置 */
@media (max-width: 768px) {
  .theme-toggle {
    top: 12px;
    right: 12px;
  }
}