:root {
  --accent-color: #4a9eff;
  --accent-soft: rgba(74, 158, 255, 0.1);
  --accent-medium: rgba(74, 158, 255, 0.18);
  --text-primary: #1a1a2e;
  --text-secondary: #555;
  --text-muted: #999;
  --glass-bg: rgba(255, 255, 255, 0.55);
  --glass-border: rgba(255, 255, 255, 0.6);
  --glass-shadow: 0 2px 16px rgba(0, 0, 0, 0.04);
  --header-bg: rgba(245, 247, 252, 0.88);
  --header-border: rgba(180, 195, 220, 0.35);
  --footer-bg: rgba(242, 244, 248, 0.88);
  --footer-border: rgba(180, 195, 220, 0.3);
  --divider-color: rgba(0, 0, 0, 0.06);
  --editor-bg: rgba(255, 255, 255, 0.72);
  --editor-font: 'Cascadia Code', 'Fira Code', 'Consolas', 'Monaco', monospace;
  --editor-text: #2c2c2c;
  --preview-bg: rgba(248, 250, 252, 0.6);
  --toolbar-bg: rgba(255, 255, 255, 0.65);
  --toolbar-shadow: 0 4px 24px rgba(0, 0, 0, 0.06);
  --btn-bg: rgba(255, 255, 255, 0.7);
  --scrollbar-thumb: rgba(0, 0, 0, 0.1);
  --scrollbar-thumb-hover: rgba(0, 0, 0, 0.2);
  --splitter-handle: rgba(0, 0, 0, 0.12);
  --sidebar-bg: rgba(250, 250, 253, 0.85);
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --radius: 10px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  height: 100vh;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  overflow: hidden;
  color: var(--text-primary);
  background: linear-gradient(135deg, #e8f0fe 0%, #f5f7fa 30%, #fef6f0 70%, #f0f4ff 100%);
  background-attachment: fixed;
}

/* ── Header ── */

header {
  background: var(--header-bg);
  color: var(--text-primary);
  padding: 0 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 52px;
  flex-shrink: 0;
  box-shadow: 0 1px 8px rgba(0, 0, 0, 0.06);
  z-index: 100;
  position: relative;
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid var(--header-border);
}

header h1 {
  margin: 0;
  font-size: 17px;
  font-weight: 600;
  letter-spacing: 0.3px;
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text-primary);
}

header h1::before {
  content: '';
  display: inline-block;
  width: 20px;
  height: 20px;
  background: var(--accent-color);
  border-radius: 5px;
  -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20'%3E%3Cpath d='M2 4h6v2H4v10h4v2H2V4zm10 0h6v14h-6v-2h4V6h-4V4z' fill='black'/%3E%3C/svg%3E") center / contain no-repeat;
  mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20'%3E%3Cpath d='M2 4h6v2H4v10h4v2H2V4zm10 0h6v14h-6v-2h4V6h-4V4z' fill='black'/%3E%3C/svg%3E") center / contain no-repeat;
}

header .toolbar {
  display: flex;
  gap: 6px;
}

.header-left {
  display: flex;
  align-items: center;
  gap: 10px;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 6px;
}

/* 移动端菜单按钮：仅移动端显示 */
#mobile-menu-btn {
  display: none;
}

.icon-btn {
  background-color: var(--btn-bg);
  color: var(--text-secondary);
  border: 1px solid var(--header-border);
  padding: 6px;
  border-radius: 8px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

.icon-btn:hover {
  background-color: var(--accent-soft);
  border-color: var(--accent-color);
  color: var(--accent-color);
  transform: translateY(-1px);
}

.icon-btn svg {
  fill: currentColor;
}

header .toolbar button,
#mode-toggle {
  background-color: var(--btn-bg);
  color: var(--text-secondary);
  border: 1px solid var(--header-border);
  padding: 6px 16px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 13px;
  font-weight: 500;
  transition: all var(--transition);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

header .toolbar button:hover,
#mode-toggle:hover {
  background-color: var(--accent-soft);
  border-color: var(--accent-color);
  color: var(--accent-color);
  transform: translateY(-1px);
  box-shadow: 0 2px 8px rgba(74, 158, 255, 0.15);
}

header .toolbar button:active,
#mode-toggle:active {
  background-color: var(--accent-medium);
  transform: translateY(0);
}

/* ── Layout ── */

#app {
  display: flex;
  flex-direction: column;
  height: 100%;
}

main {
  display: flex;
  flex: 1;
  overflow: hidden;
  min-height: 0;
}

/* ── Editor ── */

#editor-container {
  width: 40%;
  flex-shrink: 0;
  height: 100%;
  background: var(--editor-bg);
  position: relative;
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
}

#editor {
  width: 100%;
  height: 100%;
  resize: none;
  padding: 16px 20px;
  border: none;
  background: transparent;
  font-family: var(--editor-font);
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--editor-text);
  outline: none;
  tab-size: 2;
}

#editor::placeholder {
  color: var(--text-muted);
  line-height: 1.8;
}

#editor::-webkit-scrollbar {
  width: 6px;
}

#editor::-webkit-scrollbar-track {
  background: transparent;
}

#editor::-webkit-scrollbar-thumb {
  background: var(--scrollbar-thumb);
  border-radius: 3px;
}

#editor::-webkit-scrollbar-thumb:hover {
  background: var(--scrollbar-thumb-hover);
}

/* ── Sidebar ── */

#sidebar {
  width: 220px;
  flex-shrink: 0;
  height: 100%;
  background: var(--sidebar-bg);
  border-right: 1px solid var(--divider-color);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  transition: width 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
}

#sidebar.collapsed {
  width: 0;
  border-right: none;
}

#sidebar.no-anim {
  transition: none;
}

.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 14px;
  border-bottom: 1px solid var(--divider-color);
  font-size: 13px;
  font-weight: 600;
  color: var(--text-secondary);
  flex-shrink: 0;
}

.sidebar-header button {
  background: var(--btn-bg);
  border: 1px solid var(--header-border);
  border-radius: 6px;
  cursor: pointer;
  font-size: 16px;
  color: var(--text-secondary);
  width: 26px;
  height: 26px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s;
  line-height: 1;
}

.sidebar-header button:hover {
  background: var(--accent-soft);
  color: var(--accent-color);
  border-color: var(--accent-color);
}

.sidebar-docs {
  flex: 1;
  overflow-y: auto;
  padding: 6px;
}

.sidebar-docs::-webkit-scrollbar {
  width: 4px;
}

.sidebar-docs::-webkit-scrollbar-thumb {
  background: var(--scrollbar-thumb);
  border-radius: 2px;
}

.sidebar-empty {
  text-align: center;
  color: var(--text-muted);
  font-size: 12px;
  padding: 20px 10px;
}

.doc-item {
  padding: 8px 10px;
  border-radius: 6px;
  cursor: pointer;
  transition: background 0.2s;
  position: relative;
  margin-bottom: 2px;
}

.doc-item:hover {
  background: var(--accent-soft);
}

.doc-item.active {
  background: var(--accent-medium);
}

.doc-item-title {
  font-size: 13px;
  color: var(--text-primary);
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  padding-right: 20px;
}

.doc-item-time {
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 2px;
}

.doc-item-delete {
  position: absolute;
  top: 50%;
  right: 6px;
  transform: translateY(-50%);
  width: 20px;
  height: 20px;
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  border-radius: 4px;
  display: none;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  line-height: 1;
}

.doc-item:hover .doc-item-delete {
  display: flex;
}

.doc-item-delete:hover {
  background: rgba(255, 99, 71, 0.15);
  color: #ff6347;
}

/* ── Splitter ── */

#splitter {
  width: 5px;
  flex-shrink: 0;
  cursor: col-resize;
  background: var(--divider-color);
  position: relative;
  z-index: 10;
  transition: background 0.2s;
  touch-action: none;
}

#splitter::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 3px;
  height: 32px;
  border-radius: 2px;
  background: var(--splitter-handle);
  transition: background 0.2s;
}

#splitter:hover::after,
#splitter.dragging::after {
  background: var(--accent-color);
}

#splitter:hover,
#splitter.dragging {
  background: rgba(74, 158, 255, 0.1);
}

/* ── Theme Selector ── */

.theme-selector {
  position: relative;
}

.theme-dropdown {
  display: none;
  position: absolute;
  top: calc(100% + 6px);
  right: 0;
  background: var(--header-bg);
  border: 1px solid var(--header-border);
  border-radius: 8px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.1);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  backdrop-filter: blur(20px) saturate(180%);
  padding: 4px;
  min-width: 100px;
  z-index: 200;
}

.theme-dropdown.show {
  display: flex;
  flex-direction: column;
}

.theme-dropdown button {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  padding: 6px 14px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 13px;
  text-align: left;
  transition: all 0.2s;
  white-space: nowrap;
}

.theme-dropdown button:hover {
  background: var(--accent-soft);
  color: var(--accent-color);
}

.theme-dropdown button.active {
  background: var(--accent-medium);
  color: var(--accent-color);
  font-weight: 500;
}

/* ── 夜间模式 ── */

body.night-mode {
  --text-primary: #e0e0e0;
  --text-secondary: #aaa;
  --text-muted: #777;
  --glass-bg: rgba(30, 30, 45, 0.55);
  --glass-border: rgba(60, 60, 80, 0.4);
  --header-bg: rgba(20, 20, 35, 0.88);
  --header-border: rgba(60, 60, 80, 0.35);
  --footer-bg: rgba(20, 20, 35, 0.88);
  --footer-border: rgba(60, 60, 80, 0.3);
  --divider-color: rgba(255, 255, 255, 0.06);
  --editor-bg: rgba(30, 30, 45, 0.72);
  --editor-text: #e0e0e0;
  --preview-bg: rgba(25, 25, 40, 0.6);
  --toolbar-bg: rgba(30, 30, 45, 0.65);
  --btn-bg: rgba(255, 255, 255, 0.08);
  --scrollbar-thumb: rgba(255, 255, 255, 0.15);
  --scrollbar-thumb-hover: rgba(255, 255, 255, 0.25);
  --splitter-handle: rgba(255, 255, 255, 0.15);
  --sidebar-bg: rgba(20, 20, 35, 0.85);
  background: linear-gradient(135deg, #0d1117 0%, #161b22 30%, #1a1a2e 70%, #0d1117 100%);
  background-attachment: fixed;
}

body.night-mode .markmap-node text {
  fill: #e0e0e0;
}

body.night-mode .markmap-link {
  stroke: rgba(255, 255, 255, 0.15);
}

/* ── 思维导图节点内图片尺寸 ── */

.markmap-node img {
  max-width: 200px;
  max-height: 150px;
  border-radius: 4px;
  object-fit: contain;
}

/* ── Preview ── */

#markmap-container {
  flex: 1;
  height: 100%;
  position: relative;
  background: var(--preview-bg);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
}

#markmap {
  width: 100%;
  height: 100%;
  -webkit-user-select: none;
  -moz-user-select: none;
  user-select: none;
}

/* ── Footer ── */

footer {
  background: var(--footer-bg);
  color: var(--text-muted);
  text-align: center;
  padding: 6px 0;
  font-size: 11.5px;
  flex-shrink: 0;
  letter-spacing: 0.3px;
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  backdrop-filter: blur(20px) saturate(180%);
  border-top: 1px solid var(--footer-border);
  box-shadow: 0 -1px 6px rgba(0, 0, 0, 0.04);
}

/* ── Floating Toolbar ── */

.markmap-toolbar {
  position: absolute;
  bottom: 16px;
  right: 16px;
  display: flex;
  gap: 4px;
  z-index: 10000;
  background: var(--toolbar-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  padding: 6px;
  box-shadow: var(--toolbar-shadow);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  backdrop-filter: blur(20px) saturate(180%);
}

.markmap-btn {
  width: 32px;
  height: 32px;
  padding: 5px;
  background: transparent;
  border: none;
  border-radius: 7px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition);
  color: var(--text-secondary);
  position: relative;
}

.markmap-btn::after {
  content: attr(data-tooltip);
  position: absolute;
  bottom: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%) translateY(4px);
  background: rgba(40, 42, 60, 0.92);
  color: #fff;
  padding: 4px 10px;
  border-radius: 6px;
  font-size: 12px;
  font-weight: 500;
  white-space: nowrap;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.2s ease, transform 0.2s ease;
  z-index: 10001;
}

.markmap-btn::before {
  content: '';
  position: absolute;
  bottom: calc(100% + 3px);
  left: 50%;
  transform: translateX(-50%);
  border: 5px solid transparent;
  border-top-color: rgba(40, 42, 60, 0.92);
  opacity: 0;
  transition: opacity 0.2s ease;
  pointer-events: none;
}

.markmap-btn:hover::after {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

.markmap-btn:hover::before {
  opacity: 1;
}

.markmap-btn:hover {
  background: var(--accent-soft);
  color: var(--accent-color);
  transform: translateY(-1px);
}

.markmap-btn:active {
  transform: translateY(0);
  background: var(--accent-medium);
}

.markmap-btn svg {
  width: 18px;
  height: 18px;
  fill: currentColor;
}

/* 自动适应窗口激活状态 */
.markmap-btn.autofit-active {
  background: var(--accent-soft);
  color: var(--accent-color);
}

.markmap-btn.autofit-active::after {
  background: var(--accent-color);
}

.markmap-btn.autofit-active::before {
  border-top-color: var(--accent-color);
}

/* 激活状态脉冲指示点 */
.markmap-btn.autofit-active svg {
  animation: autofit-pulse 2s ease-in-out infinite;
}

@keyframes autofit-pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

/* ── PDF 方向选择弹出菜单 ── */

.pdf-orientation-menu {
  background: var(--toolbar-bg);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  backdrop-filter: blur(20px) saturate(180%);
  border: 1px solid var(--header-border);
  border-radius: 10px;
  box-shadow: var(--toolbar-shadow);
  padding: 4px;
  z-index: 10000;
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 140px;
  animation: pdfMenuFadeIn 0.15s ease-out;
}

@keyframes pdfMenuFadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: translateY(0); }
}

.pdf-orientation-item {
  background: transparent;
  border: none;
  padding: 8px 12px;
  border-radius: 6px;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  gap: 2px;
  text-align: left;
  transition: all 0.15s;
}

.pdf-orientation-item:hover {
  background: var(--accent-soft);
}

.pdf-orientation-label {
  font-size: 13px;
  font-weight: 500;
  color: var(--text-primary);
}

.pdf-orientation-desc {
  font-size: 11px;
  color: var(--text-muted);
}

/* ── Fullscreen ── */

body.fullscreen header,
body.fullscreen footer,
body.fullscreen #editor-container,
body.fullscreen #splitter,
body.fullscreen #sidebar {
  display: none !important;
}

body.fullscreen #markmap-container {
  position: fixed !important;
  top: 0 !important;
  left: 0 !important;
  right: 0 !important;
  bottom: 0 !important;
  width: 100vw !important;
  height: 100vh !important;
  z-index: 9999 !important;
  border: none !important;
}

body.fullscreen .markmap-toolbar {
  bottom: 24px;
  right: 24px;
}

/* ── 移动端响应式布局 ── */
/* 窄屏设备：编辑区在上，渲染区在下，纵向排列 */

@media (max-width: 768px) {
  /* Header：紧凑高度 */
  header {
    height: 48px;
    padding: 0 10px;
  }

  header h1 {
    font-size: 15px;
  }

  .header-left {
    gap: 6px;
  }

  /* 日间/夜间按钮：常驻显示，缩小尺寸 */
  #mode-toggle {
    padding: 5px 10px;
    font-size: 12px;
  }

  /* 工具栏：改为下拉浮层（用 header 前缀提升特异性，覆盖桌面端 header .toolbar） */
  header .toolbar {
    display: none;
    position: absolute;
    top: 48px;
    right: 8px;
    flex-direction: column;
    background: var(--header-bg);
    border: 1px solid var(--header-border);
    border-radius: 10px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.12);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    backdrop-filter: blur(20px) saturate(180%);
    padding: 6px;
    gap: 2px;
    z-index: 200;
    min-width: 140px;
  }

  header .toolbar.show {
    display: flex;
  }

  header .toolbar button {
    width: 100%;
    text-align: left;
    padding: 10px 14px;
    font-size: 13px;
    border: none;
    background: transparent;
    border-radius: 8px;
    justify-content: flex-start;
  }

  header .toolbar button:hover {
    transform: none;
    box-shadow: none;
  }

  /* 主题选择器：下拉内联展开 */
  .theme-selector .theme-dropdown {
    position: static;
    box-shadow: none;
    border: none;
    background: transparent;
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
    padding: 0 0 0 12px;
    min-width: 0;
  }

  .theme-selector .theme-dropdown.show {
    display: flex;
    flex-direction: column;
  }

  .theme-dropdown button {
    padding: 8px 12px;
    font-size: 12px;
  }

  /* 显示移动端菜单按钮 */
  #mobile-menu-btn {
    display: flex;
    padding: 6px;
  }

  /* 菜单打开时按钮激活态 */
  #mobile-menu-btn.menu-active {
    background-color: var(--accent-soft);
    border-color: var(--accent-color);
    color: var(--accent-color);
  }

  .icon-btn {
    padding: 6px;
  }

  /* 移动端禁用 :hover 粘连，改用 JS 控制 active 状态 */
  .icon-btn:hover,
  header .toolbar button:hover,
  #mode-toggle:hover {
    background-color: var(--btn-bg);
    border-color: var(--header-border);
    color: var(--text-secondary);
    transform: none;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
  }

  /* main 改为纵向排列 */
  main {
    flex-direction: column;
  }

  /* 编辑区：上方，固定比例高度 */
  #editor-container {
    width: 100% !important;
    height: 40%;
    flex-shrink: 0;
  }

  /* iOS 防止聚焦缩放：font-size 需 >= 16px */
  #editor {
    font-size: 16px;
    padding: 12px 14px;
  }

  /* 分割线：改为水平方向 */
  #splitter {
    width: 100%;
    height: 5px;
    cursor: row-resize;
  }

  #splitter::after {
    width: 32px;
    height: 3px;
  }

  /* 渲染区：下方，自动填充剩余空间 */
  #markmap-container {
    flex: 1;
    min-height: 0;
  }

  /* 侧边栏：改为浮层覆盖 */
  #sidebar {
    position: fixed;
    top: 48px;
    left: 0;
    bottom: 0;
    width: 240px;
    z-index: 500;
    box-shadow: 4px 0 16px rgba(0, 0, 0, 0.15);
  }

  #sidebar.collapsed {
    width: 0;
    border-right: none;
    box-shadow: none;
  }

  /* 底部浮动工具栏调整 */
  .markmap-toolbar {
    bottom: 12px;
    right: 12px;
  }

  /* footer 隐藏，节省空间 */
  footer {
    display: none;
  }
}