/**
 * Mobile Enhancement Styles
 * All rules scoped to mobile viewport (≤640px)
 * Prefix: .me- (mobile-enhance)
 *
 * Provides: BottomNav, header hiding, ActionSheet, SearchOverlay,
 * CategoryPanel, BackToTop, PullToRefresh, touch feedback, settings menu
 */

@media (max-width: 640px) {

  /* ==========================================================================
     1. Header / CategoryTabs Hiding & Space Reclaim
     ========================================================================== */

  .nav-card {
    display: none !important;
    margin: 0 !important;
    padding: 0 !important;
  }

  /* Override collapsed-header toggle — nav-card is always hidden */
  body.tr-mobile-top-collapsed .nav-card,
  body:not(.tr-mobile-top-collapsed) .nav-card {
    display: none !important;
  }

  /* 隐藏页脚信息（移动端不需要） */
  .tr-footer-info {
    display: none !important;
  }

  /* 登录弹窗移动端适配：确保内容可滚动 */
  .login-modal-overlay {
    padding: 16px !important;
    align-items: flex-start !important;
    padding-top: env(safe-area-inset-top, 24px) !important;
  }
  .login-modal-container {
    max-height: calc(100vh - 32px);
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    margin: auto 0;
  }

  /* ==========================================================================
     2. Body Padding & Background
     ========================================================================== */

  /* ==========================================================================
     3. Content Area Top Positioning
     ========================================================================== */

  .tab-content-area {
    padding: 0 !important;
    border-radius: 0 !important;
    box-shadow: none !important;
    background: #fff !important;
    margin: 0 !important;
  }

  .tab-pane {
    padding: 0 !important;
    margin: 0 !important;
  }

  /* 移动端容器和卡片间距压缩 */
  .main-container {
    width: 100% !important;
    max-width: 100% !important;
    padding: 0 !important;
    margin: 0 !important;
    gap: 0 !important;
    min-height: 100vh !important;
  }

  body {
    padding-top: 0 !important;
    padding-bottom: calc(50px + env(safe-area-inset-bottom)) !important;
    margin: 0 !important;
    background: #fff !important;
  }

  .platform-grid {
    gap: 0 !important;
    padding: 0 !important;
    margin: 0 !important;
    display: flex !important;
    flex-wrap: nowrap !important;
    overflow-x: auto !important;
    overflow-y: hidden !important;
    scroll-snap-type: x mandatory !important;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
  }

  .platform-grid::-webkit-scrollbar {
    display: none;
  }

  .tab-content-area .platform-grid > .platform-card,
  .platform-card {
    border-radius: 0 !important;
    margin: 0 !important;
    box-shadow: none !important;
    flex: 0 0 100% !important;
    width: 100% !important;
    min-width: 100% !important;
    scroll-snap-align: start !important;
    scroll-snap-stop: always !important;
    border: none !important;
    border-bottom: none !important;
    max-height: none !important;
    height: auto !important;
    overflow-y: visible !important;
    transform: none !important;
  }

  /* ==========================================================================
     4. BottomNav
     ========================================================================== */

  .me-bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 9999;
    display: flex;
    align-items: center;
    justify-content: space-around;
    height: 50px;
    background: #fff;
    border-top: 1px solid #e5e7eb;
    padding-bottom: env(safe-area-inset-bottom);
    box-sizing: content-box;
  }

  .me-nav-btn {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    height: 50px;
    padding: 0;
    border: none;
    background: transparent;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
    position: relative;
  }

  .me-nav-btn svg {
    width: 24px;
    height: 24px;
    color: #6b7280;
    transition: color 0.15s ease;
  }

  .me-nav-btn.active svg {
    color: var(--primary-color, #4f46e5);
  }

  /* Small dot indicator for bookmark cycle state */
  .me-nav-btn .me-dot {
    position: absolute;
    top: 8px;
    right: calc(50% - 16px);
    width: 5px;
    height: 5px;
    border-radius: 50%;
    background: var(--primary-color, #4f46e5);
    opacity: 0;
    transition: opacity 0.15s ease;
  }

  .me-nav-btn.active .me-dot {
    opacity: 1;
  }

  /* ==========================================================================
     5. Back-to-Top Button (placeholder — JS creates DOM later)
     ========================================================================== */

  .me-back-to-top {
    position: fixed;
    right: 16px;
    bottom: calc(50px + env(safe-area-inset-bottom) + 16px);
    z-index: 9998;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: #fff;
    border: 1px solid #e5e7eb;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    transform: scale(0.8);
    pointer-events: none;
    transition: opacity 0.2s ease, transform 0.2s ease;
    -webkit-tap-highlight-color: transparent;
  }

  .me-back-to-top.visible {
    opacity: 1;
    transform: scale(1);
    pointer-events: auto;
  }

  .me-back-to-top svg {
    width: 20px;
    height: 20px;
    color: #6b7280;
  }

  /* ==========================================================================
     6. Pull-to-Refresh Indicator (placeholder)
     ========================================================================== */

  .me-pull-indicator {
    position: fixed;
    top: 0;
    left: 50%;
    transform: translateX(-50%) translateY(-60px);
    z-index: 9997;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: #fff;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.12);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform 0.2s ease;
    pointer-events: none;
  }

  .me-pull-indicator svg {
    width: 20px;
    height: 20px;
    color: #6b7280;
    transition: transform 0.2s ease;
  }

  .me-pull-indicator.refreshing svg {
    animation: me-spin 0.8s linear infinite;
  }

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

  /* ==========================================================================
     7. ActionSheet (placeholder)
     ========================================================================== */

  .me-action-sheet-overlay {
    position: fixed;
    inset: 0;
    z-index: 10000;
    background: rgba(0, 0, 0, 0.4);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.25s ease, visibility 0.25s ease;
  }

  .me-action-sheet-overlay.open {
    opacity: 1;
    visibility: visible;
  }

  .me-action-sheet {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 10001;
    background: #fff;
    border-radius: 16px 16px 0 0;
    padding: 8px 0;
    padding-bottom: env(safe-area-inset-bottom);
    transform: translateY(100%);
    transition: transform 0.3s cubic-bezier(0.32, 0.72, 0, 1);
  }

  .me-action-sheet-overlay.open .me-action-sheet,
  .me-action-sheet.open {
    transform: translateY(0);
  }

  .me-action-sheet-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px 20px;
    font-size: 15px;
    color: #1f2937;
    border: none;
    background: transparent;
    width: 100%;
    text-align: left;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
  }

  .me-action-sheet-item:active {
    background: rgba(0, 0, 0, 0.04);
  }

  .me-action-sheet-item svg {
    width: 20px;
    height: 20px;
    color: #6b7280;
    flex-shrink: 0;
  }

  .me-action-sheet-divider {
    height: 1px;
    background: #f3f4f6;
    margin: 4px 20px;
  }

  .me-action-sheet-cancel {
    display: block;
    width: 100%;
    padding: 14px 20px;
    font-size: 15px;
    color: #6b7280;
    text-align: center;
    border: none;
    background: transparent;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
  }

  .me-action-sheet-cancel:active {
    background: rgba(0, 0, 0, 0.04);
  }

  /* ==========================================================================
     8. SearchOverlay (placeholder)
     ========================================================================== */

  .me-search-overlay {
    position: fixed;
    inset: 0;
    z-index: 10002;
    background: #fff;
    display: flex;
    flex-direction: column;
    padding-top: env(safe-area-inset-top, 0);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: opacity 0.2s ease, transform 0.2s ease, visibility 0.2s ease;
  }

  .me-search-overlay.open {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }

  .me-search-bar {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 12px;
    border-bottom: 1px solid #f3f4f6;
  }

  .me-search-input {
    flex: 1;
    height: 38px;
    padding: 0 12px;
    font-size: 15px;
    border: 1px solid #e5e7eb;
    border-radius: 8px;
    background: #f9fafb;
    outline: none;
    -webkit-appearance: none;
    appearance: none;
  }

  .me-search-input:focus {
    border-color: var(--primary-color, #4f46e5);
    background: #fff;
  }

  .me-search-cancel {
    flex-shrink: 0;
    padding: 6px 4px;
    font-size: 15px;
    color: var(--primary-color, #4f46e5);
    border: none;
    background: transparent;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
  }

  /* ==========================================================================
     9. CategoryDrawer (left-side tree navigation)
     ========================================================================== */

  .me-drawer-overlay {
    position: fixed;
    inset: 0;
    z-index: 10000;
    background: rgba(0, 0, 0, 0.4);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.25s ease, visibility 0.25s ease;
  }

  .me-drawer-overlay.open {
    opacity: 1;
    visibility: visible;
  }

  .me-drawer {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    z-index: 10001;
    width: 75vw;
    max-width: 300px;
    background: #fff;
    display: flex;
    flex-direction: column;
    transform: translateX(-100%);
    transition: transform 0.3s cubic-bezier(0.32, 0.72, 0, 1);
  }

  .me-drawer-overlay.open .me-drawer {
    transform: translateX(0);
  }

  .me-drawer-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 16px 10px;
    flex-shrink: 0;
  }

  .me-drawer-header-title {
    font-weight: 600;
    color: #1f2937;
    font-size: 16px;
  }

  .me-drawer-close {
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: none;
    background: #f3f4f6;
    border-radius: 50%;
    cursor: pointer;
    color: #6b7280;
    font-size: 14px;
    -webkit-tap-highlight-color: transparent;
  }

  .me-drawer-tabs {
    display: flex;
    gap: 0;
    padding: 0 16px 0;
    border-bottom: 1px solid #f3f4f6;
    flex-shrink: 0;
  }

  .me-drawer-tab {
    flex: 1;
    padding: 8px 0;
    font-size: 14px;
    font-weight: 500;
    color: #6b7280;
    background: transparent;
    border: none;
    border-bottom: 2px solid transparent;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
    transition: color 0.15s ease, border-color 0.15s ease;
  }

  .me-drawer-tab.active {
    color: var(--primary-color, #4f46e5);
    border-bottom-color: var(--primary-color, #4f46e5);
  }

  .me-drawer-tab:active {
    background: rgba(0, 0, 0, 0.03);
  }

  .me-drawer-tree {
    flex: 1;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    padding: 8px 0 calc(env(safe-area-inset-bottom) + 16px);
  }

  /* Tree item row */
  .me-tree-item {
    display: flex;
    align-items: center;
    padding: 10px 12px;
    font-size: 15px;
    color: #374151;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
    transition: background 0.1s ease;
    position: relative;
    user-select: none;
  }

  .me-tree-item:active {
    background: rgba(0, 0, 0, 0.04);
  }

  .me-tree-item.active {
    color: var(--primary-color, #4f46e5);
    background: rgba(79, 70, 229, 0.06);
  }

  .me-tree-item.active::before {
    content: '';
    position: absolute;
    left: 0;
    top: 4px;
    bottom: 4px;
    width: 3px;
    background: var(--primary-color, #4f46e5);
    border-radius: 0 2px 2px 0;
  }

  /* L1 */
  .me-tree-item[data-level="1"] {
    padding-left: 12px;
    font-size: 15px;
    font-weight: 600;
  }

  /* L2 */
  .me-tree-item[data-level="2"] {
    padding-left: 32px;
    font-size: 14px;
    font-weight: 500;
  }

  /* L3 */
  .me-tree-item[data-level="3"] {
    padding-left: 52px;
    font-size: 14px;
    font-weight: 400;
  }

  /* Arrow */
  .me-tree-arrow {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 18px;
    height: 18px;
    margin-right: 6px;
    font-size: 10px;
    color: #9ca3af;
    transition: transform 0.2s ease;
    flex-shrink: 0;
  }

  .me-tree-arrow.expanded {
    transform: rotate(90deg);
  }

  /* Spacer for leaf nodes (no arrow) to keep text aligned */
  .me-tree-spacer {
    width: 18px;
    height: 18px;
    margin-right: 6px;
    flex-shrink: 0;
  }

  .me-tree-label {
    flex: 1;
    min-width: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  /* Children container */
  .me-tree-children {
    overflow: hidden;
  }

  .me-tree-children.collapsed {
    display: none;
  }

  /* View mode toggle button */
  .me-tree-mode-btn {
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: none;
    background: transparent;
    border-radius: 6px;
    cursor: pointer;
    color: #9ca3af;
    font-size: 14px;
    flex-shrink: 0;
    margin-left: 4px;
    -webkit-tap-highlight-color: transparent;
    transition: color 0.15s ease, background 0.15s ease;
  }

  .me-tree-mode-btn:active {
    background: rgba(0, 0, 0, 0.06);
    color: var(--primary-color, #4f46e5);
  }

  /* New topic button */
  .me-drawer-new-topic {
    display: flex;
    align-items: center;
    gap: 4px;
    margin: 8px 12px;
    padding: 10px 14px;
    font-size: 14px;
    color: var(--primary-color, #4f46e5);
    background: transparent;
    border: 1px dashed var(--primary-color, #4f46e5);
    border-radius: 8px;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
  }

  .me-drawer-empty {
    padding: 20px 16px;
    font-size: 13px;
    color: #9ca3af;
    text-align: center;
  }

  /* ==========================================================================
     10. Touch Feedback
     ========================================================================== */

  .news-item {
    -webkit-tap-highlight-color: transparent;
    transition: background-color 0.1s ease;
  }

  .news-item .news-title {
    -webkit-tap-highlight-color: transparent;
    text-decoration: none !important;
  }

  .news-item .news-title:active {
    text-decoration: none !important;
    opacity: 0.6;
  }

  .news-item:active {
    background-color: rgba(0, 0, 0, 0.04);
  }

  /* 移动端：点击标题展开后显示操作按钮 */
  .news-item.expanded {
    background-color: rgba(0, 0, 0, 0.02);
    border-radius: 8px;
  }

  .news-item.expanded .news-summary-btn,
  .news-item.expanded .news-comment-btn {
    opacity: 1;
    pointer-events: auto;
  }

  .news-item.expanded .tr-news-date {
    opacity: 0;
  }

  /* 兼容 .preview class（news-link.js 原始逻辑） */
  .news-item.preview .news-summary-btn,
  .news-item.preview .news-comment-btn {
    opacity: 1;
    pointer-events: auto;
  }

  .news-item.preview .tr-news-date {
    opacity: 0;
  }

  /* ==========================================================================
     11. Settings Menu (reuses ActionSheet structure)
     ========================================================================== */

  .me-settings-menu {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 10001;
    background: #fff;
    border-radius: 16px 16px 0 0;
    padding: 8px 0;
    padding-bottom: env(safe-area-inset-bottom);
    transform: translateY(100%);
    transition: transform 0.3s cubic-bezier(0.32, 0.72, 0, 1);
  }

  .me-settings-menu.open {
    transform: translateY(0);
  }

  .me-settings-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 14px 20px;
    font-size: 15px;
    color: #1f2937;
    border: none;
    background: transparent;
    width: 100%;
    text-align: left;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
  }

  .me-settings-item:active {
    background: rgba(0, 0, 0, 0.04);
  }

  .me-settings-item-left {
    display: flex;
    align-items: center;
    gap: 12px;
  }

  .me-settings-item-left svg {
    width: 20px;
    height: 20px;
    color: #6b7280;
    flex-shrink: 0;
  }

  .me-settings-toggle {
    width: 44px;
    height: 24px;
    border-radius: 12px;
    background: #d1d5db;
    border: none;
    position: relative;
    cursor: pointer;
    transition: background 0.2s ease;
    -webkit-tap-highlight-color: transparent;
  }

  .me-settings-toggle.on {
    background: var(--primary-color, #4f46e5);
  }

  .me-settings-toggle::after {
    content: '';
    position: absolute;
    top: 2px;
    left: 2px;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: #fff;
    transition: transform 0.2s ease;
  }

  .me-settings-toggle.on::after {
    transform: translateX(20px);
  }

  .me-settings-divider {
    height: 1px;
    background: #f3f4f6;
    margin: 4px 20px;
  }

  .me-settings-links {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 24px;
    padding: 10px 20px;
  }

  .me-settings-links a {
    font-size: 13px;
    color: #6b7280;
    text-decoration: none;
  }

  .me-settings-links a:active {
    color: var(--primary-color, #4f46e5);
  }

  /* (drawer tab styles are in section 9 above) */

} /* end @media (max-width: 640px) */