/* ============================================================
   AI 会计助手 · 设计系统
   桌面端专业数据工具：单色、克制、细线边框
   左侧功能栏 + 全宽聊天区（内容列居中限宽）
   浅色 / 深色双主题（跟随系统，可手动切换）
   ============================================================ */

:root {
  /* 中性色（浅色：以白为主，描边带冷调） */
  --bg: #ffffff;
  --card: #ffffff;
  --side-bg: #fbfcfe;
  --line: #e9edf4;
  --line-strong: #d9e0ec;
  --text: #171717;
  --text-secondary: #404040;
  --muted: #6b7280;
  --faint: #9aa3b2;

  /* 主色：明快蓝（按钮、强调、选中态） */
  --primary: #2f6bff;
  --primary-dark: #1f56e0;
  --primary-soft: #eef3ff;
  --primary-softer: #f7faff;
  --on-primary: #ffffff;
  --btn-disabled: #dbe3f0;

  /* 语义色 */
  --error: #dc2626;
  --error-soft: #fef2f2;
  --error-line: #fecaca;
  --ok: #16a34a;
  --ok-soft: #f0fdf4;

  /* 圆角 */
  --r-sm: 6px;
  --r-md: 8px;
  --r-lg: 10px;
  --r-xl: 12px;

  /* 阴影（克制使用） */
  --shadow-xs: 0 1px 2px rgba(0, 0, 0, .04);
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, .05);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, .06);
  --shadow-lg: 0 12px 40px rgba(0, 0, 0, .14);

  /* 焦点环 */
  --focus-ring: 0 0 0 3px rgba(47, 107, 255, .14);

  /* 其他主题相关 */
  --scrollbar: #d4dcea;
  --scrollbar-hover: #b8c5da;
  --backdrop: rgba(15, 23, 42, .4);
  --selection: rgba(47, 107, 255, .16);
  --hover-overlay: rgba(47, 107, 255, .05);

  /* 聊天内容列宽 */
  --content-w: 880px;

  /* 动效 */
  --ease-out: cubic-bezier(.22, 1, .36, 1);
  --t-fast: .15s;
  --t-med: .25s;
}

/* ---------------- 深色主题 ---------------- */
:root[data-theme="dark"] {
  --bg: #0e0e0e;
  --card: #161616;
  --side-bg: #121212;
  --line: #262626;
  --line-strong: #474747;
  --text: #ececec;
  --text-secondary: #c4c4c4;
  --muted: #8a8a8a;
  --faint: #5c5c5c;

  --primary: #ececec;
  --primary-dark: #ffffff;
  --primary-soft: #262626;
  --primary-softer: #1b1b1b;
  --on-primary: #171717;
  --btn-disabled: #333333;

  --error: #f87171;
  --error-soft: #2b1616;
  --error-line: #4d2323;
  --ok: #4ade80;
  --ok-soft: #12261a;

  --shadow-xs: 0 1px 2px rgba(0, 0, 0, .3);
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, .35);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, .4);
  --shadow-lg: 0 12px 40px rgba(0, 0, 0, .55);

  --focus-ring: 0 0 0 3px rgba(255, 255, 255, .12);

  --scrollbar: #3a3a3a;
  --scrollbar-hover: #4d4d4d;
  --backdrop: rgba(0, 0, 0, .6);
  --selection: rgba(255, 255, 255, .18);
  --hover-overlay: rgba(255, 255, 255, .08);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0e0e0e;
    --card: #161616;
    --side-bg: #121212;
    --line: #262626;
    --line-strong: #474747;
    --text: #ececec;
    --text-secondary: #c4c4c4;
    --muted: #8a8a8a;
    --faint: #5c5c5c;

    --primary: #ececec;
    --primary-dark: #ffffff;
    --primary-soft: #262626;
    --primary-softer: #1b1b1b;
    --on-primary: #171717;
    --btn-disabled: #333333;

    --error: #f87171;
    --error-soft: #2b1616;
    --error-line: #4d2323;
    --ok: #4ade80;
    --ok-soft: #12261a;

    --shadow-xs: 0 1px 2px rgba(0, 0, 0, .3);
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, .35);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, .4);
    --shadow-lg: 0 12px 40px rgba(0, 0, 0, .55);

    --focus-ring: 0 0 0 3px rgba(255, 255, 255, .12);

    --scrollbar: #3a3a3a;
    --scrollbar-hover: #4d4d4d;
    --backdrop: rgba(0, 0, 0, .6);
    --selection: rgba(255, 255, 255, .18);
    --hover-overlay: rgba(255, 255, 255, .08);
  }
}

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

html { -webkit-text-size-adjust: 100%; }

body {
  font-family: "PingFang SC", "Microsoft YaHei", "Segoe UI", system-ui, -apple-system, sans-serif;
  font-size: 14px;
  line-height: 1.6;
  color: var(--text);
  /* 页面高度锁死在视口内：消息变多时在 .messages 内部滚动，整页不再被撑长 */
  height: 100vh;
  height: 100dvh; /* 移动端动态视口高度，避免被浏览器工具栏遮挡 */
  overflow: hidden;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition: background var(--t-med), color var(--t-med);
}

::selection { background: var(--selection); }

/* SVG 图标默认尺寸（线条图标统一风格） */
.skill-chip svg, .mic-btn svg, .send-btn svg, .theme-btn svg,
.chat-action svg, .skill-action svg, .group-action svg,
.file-item .del-btn svg, .file-item .move-btn svg {
  width: 15px; height: 15px;
  flex-shrink: 0;
  display: block;
}
.chat-action svg, .skill-action svg, .group-action svg,
.file-item .del-btn svg, .file-item .move-btn svg, .file-item .preview-btn svg {
  width: 14px; height: 14px;
}

/* 加载转圈 */
.spinner {
  display: inline-block;
  width: 14px; height: 14px;
  border: 2px solid var(--line-strong);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin .7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------------- 滚动条（全局统一：所有面板/横向滚动同一细条样式） ---------------- */
* {
  scrollbar-width: thin;
  scrollbar-color: var(--scrollbar) transparent;
}
::-webkit-scrollbar {
  width: 8px;
  height: 8px; /* 横向滚动条（代码块、宽表格）与纵向同宽 */
}
::-webkit-scrollbar-thumb {
  background: var(--scrollbar);
  border-radius: 999px;
  border: 2px solid transparent;
  background-clip: content-box;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--scrollbar-hover);
  background-clip: content-box;
  border: 2px solid transparent;
}
::-webkit-scrollbar-track, ::-webkit-scrollbar-corner { background: transparent; }

/* ---------------- 整体布局 ---------------- */
.layout {
  flex: 1;
  display: flex;
  min-height: 0;
  --side-w: 280px;
  --preview-w: 520px;
}
.layout.resizing { user-select: none; cursor: col-resize; }
.layout.resizing .sidebar { transition: none; }

/* ---------------- 左侧功能栏 ---------------- */
.sidebar {
  position: relative;
  width: var(--side-w);
  flex-shrink: 0;
  min-width: 0;
  background: var(--side-bg);
  border-right: 1px solid var(--line);
  overflow: hidden;
  transition: width .3s var(--ease-out), border-color .3s var(--ease-out);
}
.sidebar-inner {
  width: var(--side-w);
  height: 100%;
  display: flex;
  flex-direction: column;
  padding: 14px 14px 10px;
  transition: width .3s var(--ease-out);
}
.layout.resizing .sidebar-inner { transition: none; }

/* 收起状态 */
.layout.sidebar-collapsed .sidebar {
  width: 0;
  border-right-color: transparent;
}

/* 收起 / 展开按钮 */
.sidebar-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 26px; height: 26px;
  margin-left: auto;
  background: none;
  border: none;
  border-radius: var(--r-sm);
  color: var(--faint);
  cursor: pointer;
  transition: color var(--t-fast), background var(--t-fast);
}
.sidebar-toggle svg { width: 15px; height: 15px; display: block; }
.sidebar-toggle:hover { color: var(--text); background: var(--primary-soft); }

.sidebar-expand {
  position: absolute;
  top: 14px; left: 14px;
  z-index: 20;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px; height: 30px;
  background: var(--card);
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  color: var(--text-secondary);
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  opacity: 0;
  pointer-events: none;
  transform: translateX(-8px);
  transition: opacity .25s var(--ease-out), transform .25s var(--ease-out),
              border-color var(--t-fast), color var(--t-fast);
}
.sidebar-expand svg { width: 15px; height: 15px; display: block; }
.sidebar-expand:hover { border-color: var(--primary); color: var(--primary); }
.layout.sidebar-collapsed .sidebar-expand {
  opacity: 1;
  pointer-events: auto;
  transform: translateX(0);
  transition-delay: .12s;
}

/* 拖拽调宽手柄 */
.sidebar-resizer {
  position: absolute;
  top: 0; right: 0;
  width: 6px; height: 100%;
  cursor: col-resize;
  z-index: 15;
  transition: background var(--t-fast);
}
.sidebar-resizer:hover, .layout.resizing .sidebar-resizer {
  background: var(--line-strong);
}

.side-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 2px 6px 14px;
}
.side-brand h1 {
  font-size: 15px;
  font-weight: 600;
  letter-spacing: .01em;
}
/* 品牌区右侧的「返回官网」小按钮 */
.home-btn {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  margin-left: 2px;
  padding: 3px 9px;
  font-size: 12px;
  color: var(--faint);
  text-decoration: none;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  white-space: nowrap;
  transition: color var(--t-fast), border-color var(--t-fast);
}
.home-btn svg { width: 12px; height: 12px; display: block; }
.home-btn:hover { color: var(--primary); border-color: var(--primary); }

/* 设置菜单：齿轮按钮 + 上弹菜单（API 控制台 / API 文档 / 主题切换） */
.settings-wrap { position: relative; }
.settings-menu {
  position: absolute;
  bottom: 38px;
  right: 0;
  min-width: 148px;
  background: var(--card);
  border: 1px solid var(--line-strong);
  border-radius: var(--r-md);
  box-shadow: var(--shadow-md);
  padding: 4px;
  z-index: 30;
  animation: fade-in var(--t-fast) var(--ease-out);
}
.settings-item {
  display: flex;
  align-items: center;
  gap: 8px;
  width: 100%;
  padding: 7px 10px;
  font-size: 13px;
  font-family: inherit;
  color: var(--text-secondary);
  text-decoration: none;
  text-align: left;
  background: none;
  border: none;
  border-radius: var(--r-sm);
  cursor: pointer;
  transition: background var(--t-fast), color var(--t-fast);
}
.settings-item svg { width: 14px; height: 14px; flex-shrink: 0; display: block; }
.settings-item:hover { background: var(--primary-soft); color: var(--text); }
.logo {
  width: 28px; height: 28px;
  border-radius: var(--r-md);
  background: var(--primary);
  display: block;
  object-fit: cover;
  flex-shrink: 0;
}

/* 功能区：无边框分节，用细分隔线区分 */
.sidebar .card {
  background: transparent;
  border: none;
  border-radius: 0;
  border-bottom: 1px solid var(--line);
  padding: 10px 6px 14px;
}

.card h2 {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .05em;
  color: var(--muted);
  margin-bottom: 10px;
}

.card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 10px;
}
.card-head h2 { margin-bottom: 0; }
.h2-hint {
  font-size: 11px;
  color: var(--faint);
  font-weight: 400;
  margin-left: 6px;
  letter-spacing: 0;
  text-transform: none;
}
.card-head-actions { display: flex; align-items: center; gap: 2px; flex-shrink: 0; }

/* 数据卡片：可收起 */
.card-toggle {
  display: flex;
  flex: 1;
  align-items: center;
  justify-content: space-between;
  gap: 6px;
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
  color: inherit;
  min-width: 0;
}
.card-toggle-title {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .05em;
  color: var(--muted);
  transition: color var(--t-fast);
  text-align: left;
}
.card-toggle:hover .card-toggle-title { color: var(--text-secondary); }
/* 收起指示箭头：展开朝下，收起朝右 */
.card-toggle .fold-icon {
  width: 13px; height: 13px;
  color: var(--faint);
  flex-shrink: 0;
  margin-right: 2px;
  transition: color var(--t-fast), transform var(--t-med) var(--ease-out);
}
.card-toggle:hover .fold-icon { color: var(--text-secondary); }
.files-card.collapsed .card-toggle .fold-icon { transform: rotate(-90deg); }
.files-card.collapsed .card-head { margin-bottom: 0; }

.files-card .card-body {
  display: grid;
  grid-template-rows: 1fr;
  transition: grid-template-rows var(--t-med) var(--ease-out);
}
.files-card .card-body-inner { overflow: hidden; min-height: 0; }
.files-card.collapsed .card-body { grid-template-rows: 0fr; }

/* 会话区分节：拉伸填充剩余空间 */
.chats-card {
  flex: 1;
  min-height: 140px;
  display: flex;
  flex-direction: column;
}
.chats-card .chat-list { flex: 1; max-height: none; }

/* 侧栏底部控制区 */
.sidebar-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 10px 6px 0;
}
.sidebar-footer-actions { display: flex; align-items: center; gap: 6px; }

/* 试用/会员额度徽标：访客显示今日剩余次数，正式用户显示身份 */
.allowance-badge {
  font-size: 12px;
  color: var(--text-secondary);
  background: var(--card);
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  padding: 3px 10px;
  cursor: pointer;
  white-space: nowrap;
  transition: all var(--t-fast);
}
.allowance-badge:hover { border-color: var(--primary); color: var(--primary); }
.allowance-badge.member { color: var(--ok); border-color: var(--ok); }
.allowance-badge.low { color: var(--error); border-color: var(--error); }

.theme-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px; height: 30px;
  background: var(--card);
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--t-fast);
}
.theme-btn:hover { border-color: var(--primary); color: var(--primary); }

/* 设置齿轮按钮：32/16 尺寸组合在 100%/125%/150% 缩放比下都落整像素，
   避免齿轮因半像素栅格化看起来不居中（须晚于 .theme-btn 与全局 svg 15px 规则） */
.settings-btn { width: 32px; height: 32px; }
.settings-btn svg { width: 16px; height: 16px; }

/* ---------------- 上传区 ---------------- */
/* “+”图标按钮（卡片头部） */
.icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 24px; height: 24px;
  background: none;
  border: none;
  border-radius: var(--r-sm);
  color: var(--muted);
  cursor: pointer;
  transition: background var(--t-fast), color var(--t-fast);
}
.icon-btn svg { width: 15px; height: 15px; }
.icon-btn:hover { background: var(--primary-soft); color: var(--text); }

/* 拖拽上传指示层：拖文件进入数据卡片时显示 */
.files-card { position: relative; }
.drop-overlay {
  position: absolute;
  inset: 0;
  z-index: 6;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 10px;
  background: color-mix(in srgb, var(--side-bg) 82%, transparent);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--t-med) var(--ease-out);
}
.files-card.dragover .drop-overlay { opacity: 1; }
.drop-overlay-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  width: 100%;
  height: 100%;
  min-height: 110px;
  justify-content: center;
  border: 1.5px dashed var(--line-strong);
  border-radius: var(--r-md);
  color: var(--text-secondary);
  font-size: 13px;
  background: var(--card);
}
.files-card.dragover .drop-overlay-box { animation: drop-pulse 1.2s var(--ease-out) infinite; }
.drop-overlay-box svg { width: 22px; height: 22px; color: var(--muted); }
.drop-overlay-hint { font-size: 11.5px; color: var(--faint); }
@keyframes drop-pulse {
  0%, 100% { border-color: var(--line-strong); transform: scale(1); }
  50% { border-color: var(--primary); transform: scale(1.015); }
}

.upload-status {
  margin-top: 10px;
  font-size: 12.5px;
  padding: 7px 11px;
  border-radius: var(--r-sm);
  animation: fade-in var(--t-med) var(--ease-out);
  transition: opacity .4s;
}
.upload-status.fading { opacity: 0; }
.upload-status.ok { color: var(--ok); background: var(--ok-soft); }
.upload-status.error { color: var(--error); background: var(--error-soft); }

.hidden { display: none !important; }

/* ---------------- 文件列表 ---------------- */
.file-list { list-style: none; max-height: min(420px, 45vh); overflow-y: auto; margin: 0 -4px; padding: 0 4px; }
.file-list .empty { color: var(--faint); font-size: 13px; padding: 10px 4px; }
/* 文件名搜索框：放大镜内嵌 + 胶囊形（与侧栏 skill-chip 同族），有内容时显示一键清空 */
.file-search-box {
  position: relative;
  display: flex;
  align-items: center;
  margin-bottom: 8px;
}
.file-search-icon {
  position: absolute;
  left: 11px;
  width: 13px; height: 13px;
  color: var(--faint);
  pointer-events: none;
  transition: color var(--t-fast);
}
.file-search {
  width: 100%;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  padding: 6px 30px 6px 31px;
  font-size: 12.5px;
  font-family: inherit;
  color: var(--text);
  background: var(--card);
  outline: none;
  transition: border-color var(--t-fast), box-shadow var(--t-fast);
}
.file-search:focus { border-color: var(--primary); box-shadow: var(--focus-ring); }
.file-search:focus ~ .file-search-icon,
.file-search-box:focus-within .file-search-icon { color: var(--primary); }
.file-search::placeholder { color: var(--faint); }
.file-search-clear {
  position: absolute;
  right: 5px;
  display: none;
  align-items: center;
  justify-content: center;
  width: 20px; height: 20px;
  background: none;
  border: none;
  border-radius: 999px;
  color: var(--faint);
  cursor: pointer;
  transition: color var(--t-fast), background var(--t-fast);
}
.file-search-clear svg { width: 11px; height: 11px; display: block; }
.file-search-clear:hover { color: var(--text); background: var(--primary-soft); }
.file-search-box.has-text .file-search-clear { display: inline-flex; }
.file-item {
  display: flex; align-items: center; gap: 9px;
  padding: 7px 8px;
  border-radius: var(--r-sm);
  font-size: 13px;
  transition: background var(--t-fast);
}
.file-item + .file-item { margin-top: 1px; }
/* 整行可点击勾选（管理模式与非管理模式一致） */
.file-list .file-item { cursor: pointer; user-select: none; }
/* 添加文件到分组弹窗的勾选框 */
.move-list input[type="checkbox"] {
  width: 15px; height: 15px;
  accent-color: var(--primary);
  flex-shrink: 0;
  cursor: pointer;
}
.file-item:hover { background: var(--hover-overlay); }
.file-item input[type="checkbox"] {
  width: 15px; height: 15px;
  accent-color: var(--primary);
  flex-shrink: 0;
  cursor: pointer;
}
.file-item .name { flex: 1; word-break: break-all; line-height: 1.45; }
.file-item .meta { color: var(--faint); font-size: 11.5px; }
.file-item .badge {
  font-size: 11px;
  background: var(--primary-soft);
  color: var(--text-secondary);
  border-radius: 5px;
  padding: 1.5px 7px;
  flex-shrink: 0;
}
.file-item .del-btn, .file-item .move-btn {
  display: inline-flex; align-items: center; justify-content: center;
  background: none; border: none; cursor: pointer;
  color: var(--faint);
  padding: 5px; border-radius: var(--r-sm); flex-shrink: 0;
  transition: color var(--t-fast), background var(--t-fast);
}
.file-item .del-btn:hover { color: var(--error); background: var(--error-soft); }
.file-item .move-btn:hover { color: var(--text); background: var(--primary-soft); }
.file-item .preview-btn {
  display: inline-flex; align-items: center; justify-content: center;
  background: none; border: none; cursor: pointer;
  color: var(--faint);
  padding: 5px; border-radius: var(--r-sm); flex-shrink: 0;
  transition: color var(--t-fast), background var(--t-fast);
}
.file-item .preview-btn:hover { color: var(--primary); background: var(--primary-soft); }
/* 置顶按钮：未置顶时与预览/删除按钮同款；置顶后主色常显，一眼可辨 */
.file-item .pin-btn {
  display: inline-flex; align-items: center; justify-content: center;
  background: none; border: none; cursor: pointer;
  color: var(--faint);
  padding: 5px; border-radius: var(--r-sm); flex-shrink: 0;
  transition: color var(--t-fast), background var(--t-fast);
}
.file-item .pin-btn:hover { color: var(--primary); background: var(--primary-soft); }
.file-item .pin-btn.pinned { color: var(--primary); }
.file-item .pin-btn svg { width: 14px; height: 14px; }

.manage-bar {
  display: flex; align-items: center; gap: 10px;
  margin-top: 10px; padding-top: 10px;
  border-top: 1px solid var(--line);
  font-size: 13px; color: var(--muted);
}
.manage-bar .manage-count { flex: 1; }

/* ---------------- 文件分组 ---------------- */
.group-block {
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  margin-bottom: 6px;
  overflow: hidden;
  background: var(--card);
}
.group-head {
  display: flex; align-items: center; gap: 8px;
  padding: 8px 10px;
  font-size: 13px;
  font-weight: 550;
  cursor: pointer;
  user-select: none;
  transition: background var(--t-fast);
}
.group-head:hover { background: var(--primary-softer); }
.group-head input[type="checkbox"] { width: 15px; height: 15px; accent-color: var(--primary); flex-shrink: 0; cursor: pointer; }
.group-dot { width: 9px; height: 9px; border-radius: 50%; flex-shrink: 0; }
.group-name { flex: 1; word-break: break-all; }
.group-count { color: var(--faint); font-size: 12px; flex-shrink: 0; font-weight: 400; }
.group-action {
  display: inline-flex; align-items: center; justify-content: center;
  background: none; border: none; cursor: pointer;
  color: var(--faint);
  padding: 5px; border-radius: var(--r-sm); flex-shrink: 0;
  transition: color var(--t-fast), background var(--t-fast);
}
.group-action:hover { color: var(--text); background: var(--primary-soft); }
.group-action.danger:hover { color: var(--error); background: var(--error-soft); }
.group-arrow {
  color: var(--faint); font-size: 10px; flex-shrink: 0;
  display: inline-block;
  transition: transform var(--t-med) var(--ease-out);
}
.group-body { list-style: none; border-top: 1px solid var(--line); background: var(--primary-softer); padding: 3px 0; }
.group-body .file-item { padding-left: 28px; border-radius: 0; }
.group-empty { color: var(--faint); font-size: 12px; padding: 9px 28px; }

.ungrouped-label {
  color: var(--faint);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .05em;
  padding: 8px 8px 3px;
}

/* ---------------- 会话列表 ---------------- */
.chat-list { list-style: none; max-height: 240px; overflow-y: auto; margin: 0 -4px; padding: 0 4px; }
.chat-list .empty { color: var(--faint); font-size: 13px; padding: 10px 4px; }
.chat-item {
  display: flex; align-items: center; gap: 4px;
  padding: 7px 9px;
  border-radius: var(--r-sm);
  cursor: pointer;
  font-size: 13px;
  transition: background var(--t-fast);
}
.chat-item + .chat-item { margin-top: 1px; }
.chat-item:hover { background: var(--hover-overlay); }
.chat-item.active { background: var(--primary-soft); }
.chat-item .chat-text { flex: 1; min-width: 0; }
.chat-item .chat-title {
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
  color: var(--text-secondary);
}
.chat-item.active .chat-title { font-weight: 600; color: var(--text); }
.chat-item .chat-time { font-size: 11px; color: var(--faint); margin-top: 1px; }
.chat-item .chat-action {
  display: inline-flex; align-items: center; justify-content: center;
  background: none; border: none; cursor: pointer;
  color: var(--faint);
  padding: 5px; border-radius: var(--r-sm); flex-shrink: 0;
  opacity: 0;
  transition: opacity var(--t-fast), color var(--t-fast), background var(--t-fast);
}
.chat-item:hover .chat-action, .chat-item.active .chat-action { opacity: 1; }
.chat-item .chat-action:hover { color: var(--text); background: var(--hover-overlay); }
.chat-item .chat-action.danger:hover { color: var(--error); background: var(--error-soft); }

/* ---------------- 聊天主区（全宽，内容列居中限宽） ---------------- */
.chat-area {
  position: relative;
  flex: 1;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  overflow: hidden;
  min-width: 0;
}

.messages {
  flex: 1;
  overflow-y: auto;
  padding: 28px max(24px, calc((100% - var(--content-w)) / 2)) 16px;
  display: flex;
  flex-direction: column;
  gap: 18px;
  scroll-behavior: smooth;
}

/* 欢迎页 */
.welcome {
  margin: auto;
  text-align: center;
  color: var(--muted);
  max-width: 560px;
  padding: 20px 0;
  animation: fade-up .4s var(--ease-out);
}
.welcome h2 {
  color: var(--text);
  font-size: 22px;
  font-weight: 600;
  letter-spacing: .01em;
  margin-bottom: 8px;
}
.welcome-sub { font-size: 13.5px; color: var(--muted); margin-bottom: 26px; }
.welcome-flow {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 14px;
  margin-bottom: 30px;
}
.welcome-flow span {
  font-size: 13px;
  color: var(--text-secondary);
  white-space: nowrap;
}
.welcome-flow i {
  width: 28px; height: 1px;
  background: var(--line-strong);
  flex-shrink: 0;
}
.welcome-examples { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; }
.welcome-example {
  background: var(--card);
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  padding: 6px 14px;
  font-size: 12.5px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--t-fast);
  font-family: inherit;
}
.welcome-example:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: var(--primary-softer);
}

/* 消息 */
.msg {
  max-width: 82%;
  font-size: 14px;
  line-height: 1.75;
  white-space: pre-wrap;
  word-break: break-word;
  animation: msg-in .25s var(--ease-out);
}
.msg.user {
  align-self: flex-end;
  background: var(--primary-soft);
  color: var(--text);
  border-radius: var(--r-xl);
  border-bottom-right-radius: 4px;
  padding: 9px 14px;
}
.msg.ai {
  align-self: flex-start;
  max-width: 92%;
  color: var(--text-secondary);
  padding: 2px 0;
}
.msg.error {
  align-self: flex-start;
  background: var(--error-soft);
  border: 1px solid var(--error-line);
  border-radius: var(--r-md);
  padding: 9px 14px;
  color: var(--error);
  font-size: 13px;
}
.msg .cursor {
  display: inline-block;
  width: 8px; height: 15px;
  background: var(--text);
  vertical-align: -2px;
  animation: blink 1s infinite;
  margin-left: 3px;
  border-radius: 1.5px;
}
@keyframes blink { 0%, 100% { opacity: 1; } 50% { opacity: 0; } }

/* Markdown 渲染（ai 消息完成态） */
.msg.ai.md { white-space: normal; }
.msg.md p { margin: 0 0 8px; }
.msg.md p:last-child { margin-bottom: 0; }
.msg.md ul, .msg.md ol { margin: 4px 0 10px; padding-left: 22px; }
.msg.md li { margin: 2px 0; }
.msg.md h1, .msg.md h2, .msg.md h3, .msg.md h4 {
  color: var(--text);
  margin: 12px 0 6px;
  line-height: 1.4;
}
.msg.md h1 { font-size: 16px; }
.msg.md h2 { font-size: 15px; }
.msg.md h3, .msg.md h4 { font-size: 14px; }
.msg.md h1:first-child, .msg.md h2:first-child, .msg.md h3:first-child,
.msg.md p:first-child, .msg.md ul:first-child, .msg.md ol:first-child { margin-top: 0; }
.msg.md strong { color: var(--text); }
.msg.md code {
  font-family: ui-monospace, Consolas, "Courier New", monospace;
  font-size: 12.5px;
  background: var(--primary-softer);
  border-radius: 4px;
  padding: 1px 5px;
}
.msg.md pre {
  background: var(--card);
  border: 1px solid var(--line-strong);
  border-radius: var(--r-md);
  padding: 10px 12px;
  overflow-x: auto;
  margin: 6px 0 10px;
}
.msg.md pre code { background: none; padding: 0; }
.msg.md table {
  display: block;
  border-collapse: collapse;
  margin: 8px 0 12px;
  font-size: 13px;
  max-width: 100%;
  overflow-x: auto;
}
.msg.md th, .msg.md td {
  border: 1px solid var(--line-strong);
  padding: 5px 10px;
  text-align: left;
  white-space: nowrap;
}
.msg.md th {
  background: var(--primary-softer);
  color: var(--text);
  font-weight: 600;
}

/* 结果附件（表文件）卡片 */
.file-card {
  align-self: flex-start;
  display: flex;
  align-items: center;
  flex-wrap: wrap; /* 极窄屏时下载按钮自动落到下一行，不再挤坏文件名 */
  gap: 10px;
  background: var(--card);
  border: 1px solid var(--line-strong);
  border-radius: var(--r-md);
  padding: 10px 14px;
  width: 100%;
  max-width: 340px; /* 宽屏下保持紧凑 */
  box-sizing: border-box;
  cursor: pointer;
  animation: msg-in .25s var(--ease-out);
  transition: border-color var(--t-fast);
}
.file-card:hover { border-color: var(--primary); }
.file-card-badge {
  flex-shrink: 0;
  font-size: 11px;
  font-weight: 700;
  color: var(--text);
  background: var(--primary-softer);
  border-radius: 6px;
  padding: 4px 7px;
}
.file-card-info { flex: 1; min-width: 110px; }
.file-card-name {
  font-size: 13.5px;
  color: var(--text);
  /* 文件名单行省略号截断：窄屏下不再逐字竖排 */
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.file-card-meta { font-size: 12px; color: var(--muted); margin-top: 1px; }
.file-card-download {
  flex-shrink: 0;
  font-size: 13px;
  color: var(--text);
  text-decoration: none;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  padding: 5px 14px;
  transition: all var(--t-fast);
}
.file-card-download:hover {
  background: var(--primary-softer);
  border-color: var(--primary);
}

/* 用户消息关联的数据源 chips（气泡下方，右对齐） */
.ds-chips {
  align-self: flex-end;
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 6px;
  max-width: 82%;
}
.ds-chip {
  font-size: 12px;
  color: var(--muted);
  background: var(--card);
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  padding: 3px 10px;
  word-break: break-all;
}
/* 带数据源 id 的 chip 可点击打开预览 */
.ds-chip.clickable {
  cursor: pointer;
  transition: border-color var(--t-fast), color var(--t-fast);
}
.ds-chip.clickable:hover {
  border-color: var(--primary);
  color: var(--text);
}
.ds-chip::before {
  content: "▦";
  margin-right: 5px;
  color: var(--text-secondary);
}

/* 状态行 */
.status-line {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px max(24px, calc((100% - var(--content-w)) / 2));
  font-size: 12.5px;
  color: var(--text-secondary);
  background: var(--primary-softer);
  border-top: 1px solid var(--line);
  animation: fade-in var(--t-med);
}
.status-line::before {
  content: "";
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--text);
  flex-shrink: 0;
  animation: status-pulse 1.1s infinite var(--ease-out);
}
@keyframes status-pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: .4; transform: scale(.75); }
}

/* ---------------- 输入区 ---------------- */
.composer-tools {
  display: flex; gap: 8px;
  padding: 12px max(16px, calc((100% - var(--content-w)) / 2)) 0;
  background: var(--bg);
}

.skill-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--card);
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  padding: 5px 13px;
  font-size: 12.5px;
  color: var(--text-secondary);
  cursor: pointer;
  font-family: inherit;
  transition: all var(--t-fast);
}
.skill-chip:hover { border-color: var(--primary); color: var(--primary); }
.skill-chip.active {
  background: var(--primary-soft);
  border-color: var(--primary);
  color: var(--primary);
  font-weight: 550;
}

.composer {
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin: 10px auto 6px;
  width: min(var(--content-w), calc(100% - 32px));
  padding: 7px;
  background: var(--card);
  border: 1px solid var(--line-strong);
  border-radius: var(--r-xl);
  transition: border-color var(--t-fast), box-shadow var(--t-fast);
}
.composer:focus-within {
  border-color: var(--primary);
}
.composer textarea {
  width: 100%;
  resize: none;
  border: none;
  background: transparent;
  border-radius: var(--r-sm);
  padding: 5px 9px;
  font-size: 14px;
  font-family: inherit;
  line-height: 1.6;
  color: var(--text);
  outline: none;
  min-height: 76px;
}
.composer textarea::placeholder { color: var(--faint); }

/* 输入框底部按钮条：左侧 + / 语音，右侧发送 */
.composer-bar {
  display: flex;
  align-items: center;
  gap: 2px;
}
.composer-bar .send-btn { margin-left: auto; }

.composer-hint {
  text-align: center;
  font-size: 11.5px;
  color: var(--faint);
  padding: 3px 0 10px;
}

/* 页脚：聊天区底部的一条细条，窄屏自动换行不挤压布局 */
.app-footer {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 3px 14px;
  padding: 0 12px 8px;
  font-size: 11px;
  color: var(--faint);
}
.app-footer a { color: var(--faint); text-decoration: none; }
.app-footer a:hover { color: var(--muted); text-decoration: underline; }

/* ---------------- 按钮体系 ---------------- */
.send-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  align-self: flex-end;
  background: var(--primary);
  color: var(--on-primary);
  border: none;
  border-radius: var(--r-md);
  padding: 10px 18px;
  font-size: 13px;
  font-weight: 550;
  font-family: inherit;
  cursor: pointer;
  transition: background var(--t-fast), transform var(--t-fast) var(--ease-out);
}
.send-btn svg { width: 14px; height: 14px; }
.send-btn:hover:not(:disabled) { background: var(--primary-dark); }
.send-btn:active:not(:disabled) { transform: scale(.97); }
.send-btn:disabled {
  background: var(--btn-disabled);
  color: var(--muted);
  cursor: not-allowed;
}
.send-btn:focus-visible, .plain-btn:focus-visible, .danger-btn:focus-visible,
.link-btn:focus-visible, .mic-btn:focus-visible, .skill-chip:focus-visible,
.welcome-example:focus-visible, .theme-btn:focus-visible {
  outline: none;
  box-shadow: var(--focus-ring);
}

.plain-btn {
  background: var(--card);
  color: var(--text-secondary);
  border: 1px solid var(--line-strong);
  border-radius: var(--r-sm);
  padding: 7px 15px;
  font-size: 13px;
  font-weight: 500;
  font-family: inherit;
  cursor: pointer;
  transition: all var(--t-fast);
}
.plain-btn:hover { border-color: var(--primary); color: var(--primary); }

.danger-btn {
  background: var(--card);
  color: var(--error);
  border: 1px solid var(--error-line);
  border-radius: var(--r-sm);
  padding: 7px 15px;
  font-size: 13px;
  font-weight: 550;
  font-family: inherit;
  cursor: pointer;
  transition: all var(--t-fast);
}
.danger-btn:hover { background: var(--error); border-color: var(--error); color: #fff; }

.link-btn {
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-secondary);
  font-size: 12.5px;
  font-weight: 550;
  font-family: inherit;
  padding: 4px 7px;
  border-radius: var(--r-sm);
  transition: background var(--t-fast), color var(--t-fast);
}
.link-btn:hover { background: var(--primary-soft); color: var(--text); }

/* 语音输入 / 附件上传：无边框幽灵图标按钮 */
.mic-btn, .attach-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  align-self: flex-end;
  background: none;
  color: var(--muted);
  border: none;
  border-radius: var(--r-md);
  padding: 9px;
  font-size: 12.5px;
  font-variant-numeric: tabular-nums;
  cursor: pointer;
  min-width: 40px;
  min-height: 40px;
  font-family: inherit;
  transition: all var(--t-fast);
}
.mic-btn:hover, .attach-btn:hover { background: var(--primary-soft); color: var(--text); }
.mic-btn:disabled { opacity: .55; cursor: not-allowed; }
.mic-btn.recording {
  background: var(--error-soft);
  color: var(--error);
}
.mic-btn.transcribing {
  background: var(--primary-softer);
  color: var(--text-secondary);
}
.attach-btn svg { width: 16px; height: 16px; }

/* ---------------- 弹窗 ---------------- */
.modal {
  position: fixed; inset: 0; z-index: 50;
  display: flex; align-items: center; justify-content: center;
  animation: fade-in var(--t-fast);
}
.modal-backdrop {
  position: absolute; inset: 0;
  background: var(--backdrop);
}
.modal-panel {
  position: relative;
  width: 460px;
  max-width: calc(100vw - 32px);
  max-height: 74vh;
  overflow-y: auto;
  background: var(--card);
  border-radius: var(--r-xl);
  border: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  padding: 20px;
  box-shadow: var(--shadow-lg);
  animation: modal-in .25s var(--ease-out);
}
.modal-head { display: flex; flex-direction: column; gap: 11px; margin-bottom: 11px; }
.modal-head h3 { font-size: 15px; font-weight: 600; letter-spacing: .01em; }

.skill-search, .group-name-input {
  border: 1px solid var(--line-strong);
  border-radius: var(--r-md);
  padding: 9px 12px;
  font-size: 13.5px;
  font-family: inherit;
  color: var(--text);
  background: var(--card);
  outline: none;
  transition: border-color var(--t-fast), box-shadow var(--t-fast);
}
.skill-search:focus, .group-name-input:focus {
  border-color: var(--primary);
  box-shadow: var(--focus-ring);
}
.skill-search::placeholder, .group-name-input::placeholder {
  color: var(--faint);
}

.skill-list { list-style: none; overflow-y: auto; flex: 1; min-height: 120px; }
.skill-list .empty { color: var(--faint); font-size: 13px; padding: 14px 4px; }
.skill-item {
  display: flex; align-items: flex-start; gap: 10px;
  padding: 9px 9px;
  border-radius: var(--r-md);
  cursor: pointer;
  transition: background var(--t-fast);
}
.skill-item + .skill-item { margin-top: 1px; }
.skill-item:hover { background: var(--primary-softer); }
.skill-item input[type="checkbox"] {
  width: 15px; height: 15px;
  margin-top: 3px;
  accent-color: var(--primary);
  flex-shrink: 0;
  cursor: pointer;
}
.skill-item .skill-text { flex: 1; min-width: 0; }
.skill-item .skill-name { font-size: 13.5px; font-weight: 550; display: flex; align-items: center; gap: 6px; flex-wrap: wrap; }
.skill-item .skill-desc {
  font-size: 12px;
  color: var(--muted);
  margin-top: 2px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.skill-section-label {
  color: var(--faint);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .05em;
  padding: 8px 9px 2px;
}
.skill-badge { font-size: 11px; border-radius: 5px; padding: 1px 6px; flex-shrink: 0; font-weight: 500; }
.skill-badge.user { background: var(--ok-soft); color: var(--ok); }
.skill-badge.builtin { background: var(--primary-soft); color: var(--text-secondary); }
.skill-action {
  display: inline-flex; align-items: center; justify-content: center;
  background: none; border: none; cursor: pointer;
  color: var(--faint);
  padding: 5px; border-radius: var(--r-sm); flex-shrink: 0;
  transition: color var(--t-fast), background var(--t-fast);
}
.skill-action:hover { color: var(--text); background: var(--primary-soft); }
.skill-action.danger:hover { color: var(--error); background: var(--error-soft); }

.modal-foot {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid var(--line);
}
.modal-foot-right { display: flex; align-items: center; gap: 8px; }
.modal-foot .send-btn { padding: 8px 18px; }

/* 知识包编辑 */
.skill-edit-panel { width: 580px; }
.skill-edit-content {
  resize: vertical;
  border: 1px solid var(--line-strong);
  border-radius: var(--r-md);
  padding: 9px 12px;
  font-size: 13px;
  font-family: inherit;
  outline: none;
  line-height: 1.65;
  color: var(--text);
  background: var(--card);
  transition: border-color var(--t-fast), box-shadow var(--t-fast);
}
.skill-edit-content:focus { border-color: var(--primary); box-shadow: var(--focus-ring); }
.skill-edit-content:disabled { background: var(--bg); color: var(--muted); }
.skill-edit-bar { display: flex; align-items: center; justify-content: space-between; }
.skill-edit-count { color: var(--faint); font-size: 12px; font-variant-numeric: tabular-nums; }

/* 分组色板 */
.group-color-list { display: flex; gap: 9px; flex-wrap: wrap; }
.swatch {
  width: 24px; height: 24px;
  border-radius: 50%;
  border: none;
  cursor: pointer;
  padding: 0;
  flex-shrink: 0;
  transition: transform var(--t-fast) var(--ease-out), box-shadow var(--t-fast);
}
.swatch:hover { transform: scale(1.1); }
.swatch.selected { box-shadow: 0 0 0 2px var(--card), 0 0 0 4px currentColor; }
.group-modal-error { color: var(--error); font-size: 12.5px; }

/* 移入分组 */
.move-file-name {
  font-size: 12.5px;
  color: var(--muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.move-list { list-style: none; overflow-y: auto; flex: 1; min-height: 100px; }
.move-item {
  display: flex; align-items: center; gap: 10px;
  padding: 9px 9px;
  border-radius: var(--r-md);
  cursor: pointer;
  font-size: 13px;
  transition: background var(--t-fast);
}
.move-item + .move-item { margin-top: 1px; }
.move-item:hover { background: var(--primary-softer); }
.move-item.disabled { cursor: default; color: var(--faint); }
.move-item.disabled:hover { background: none; }
.move-item .move-dot { width: 9px; height: 9px; border-radius: 50%; flex-shrink: 0; }
.move-item .move-name { flex: 1; word-break: break-all; }
.move-item .move-check { color: var(--text); font-size: 12px; flex-shrink: 0; font-weight: 600; }
.move-item .move-count { color: var(--faint); font-size: 12px; flex-shrink: 0; }

/* 上传前同意弹窗 */
.consent-desc { font-size: 13px; color: var(--muted); line-height: 1.65; }
.consent-desc a { color: var(--primary); text-decoration: none; }
.consent-desc a:hover { text-decoration: underline; }

/* ---------------- 动画 ---------------- */
@keyframes fade-in { from { opacity: 0; } to { opacity: 1; } }
@keyframes fade-up {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes msg-in {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes modal-in {
  from { opacity: 0; transform: translateY(10px) scale(.98); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
    scroll-behavior: auto !important;
  }
}

/* 移动端抽屉遮罩：抽屉化边栏伸出时盖在会话区上方（仅 ≤920px 由 JS 控制显隐） */
.drawer-backdrop {
  position: fixed;
  inset: 0;
  background: var(--backdrop);
  z-index: 44;
}

/* ---------------- 右侧文件预览边栏 ---------------- */
.preview-panel {
  position: relative;
  width: var(--preview-w);
  flex-shrink: 0;
  min-width: 0;
  /* 页面整体高度由 min-height:100vh 的 body 撑开，不设上限时长表格会把 .layout 顶高、
     把输入框挤出视口；这里把边栏高度钳制在视口内，内容在 .preview-body 内部滚动 */
  max-height: 100vh;
  background: var(--side-bg);
  border-left: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}
.preview-resizer {
  position: absolute;
  top: 0; left: 0;
  width: 6px; height: 100%;
  cursor: col-resize;
  z-index: 15;
  transition: background var(--t-fast);
}
.preview-resizer:hover, .layout.resizing .preview-resizer { background: var(--line-strong); }
.preview-head {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 14px 16px 10px;
  border-bottom: 1px solid var(--line);
}
.preview-head-text { flex: 1; min-width: 0; }
.preview-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  word-break: break-all;
}
.preview-sub { font-size: 12px; color: var(--muted); margin-top: 3px; }
.preview-body { flex: 1; overflow: auto; padding: 12px 14px 16px; }
.preview-loading, .preview-empty, .preview-error {
  font-size: 13px;
  color: var(--muted);
  text-align: center;
  padding: 24px 8px;
}
.preview-error { color: var(--error); }
/* 分块加载的底部提示（加载中…/加载失败） */
.preview-hint {
  font-size: 12px;
  color: var(--muted);
  text-align: center;
  padding: 10px 8px;
}
.preview-table { border-collapse: collapse; font-size: 12.5px; }
.preview-table th, .preview-table td {
  border: 1px solid var(--line-strong);
  padding: 5px 10px;
  text-align: left;
  white-space: nowrap;
  max-width: 240px;
  overflow: hidden;
  text-overflow: ellipsis;
}
.preview-table th {
  background: var(--primary-softer);
  color: var(--text);
  font-weight: 600;
  position: sticky;
  top: 0;
}

/* ---------------- 响应式 ---------------- */
@media (max-width: 1100px) {
  /* 窄屏下预览边栏改为右侧浮层，避免挤压聊天区 */
  .preview-panel {
    position: fixed;
    top: 0; right: 0; bottom: 0;
    width: min(var(--preview-w), 92vw);
    z-index: 46;
    box-shadow: var(--shadow-lg);
    animation: preview-in .25s var(--ease-out);
  }
  @keyframes preview-in {
    from { opacity: 0; transform: translateX(24px); }
    to { opacity: 1; transform: translateX(0); }
  }
  .preview-resizer { display: none; }
}
@media (max-width: 1080px) {
  .h2-hint { display: none; }
}

@media (max-width: 920px) {
  /* 手机布局：会话区占满主空间；左侧栏变为抽屉，点左上角按钮伸出、盖住部分会话区，
     点遮罩或抽屉内「收起」按钮关闭；右侧预览边栏沿用 ≤1100px 的浮层方案 */
  .sidebar {
    position: fixed;
    top: 0; left: 0; bottom: 0;
    width: min(86vw, 360px);
    z-index: 46;
    transform: translateX(-105%);
    border-right: 1px solid var(--line);
    box-shadow: var(--shadow-lg);
    transition: transform .3s var(--ease-out);
  }
  /* 覆盖桌面收起态 width:0：移动端收起 = 移出屏幕外 */
  .layout.sidebar-collapsed .sidebar { width: min(86vw, 360px); }
  .layout:not(.sidebar-collapsed) .sidebar { transform: translateX(0); }
  .sidebar-inner { width: 100%; padding: 12px 16px 8px; }
  .sidebar-resizer { display: none; }
  .chat-area { min-height: 0; max-height: 100vh; }
  .messages { padding: 18px 16px 12px; }
  .msg.user { max-width: 88%; }
  .composer { width: calc(100% - 20px); margin: 8px auto 4px; }
  .composer-tools { padding: 10px 12px 0; }
  .status-line { padding: 8px 16px; }
  .welcome-flow { gap: 10px; }
  .welcome-flow i { width: 16px; }
  .modal { align-items: flex-end; }
  .modal-panel {
    width: 100%;
    max-width: 100%;
    max-height: 82vh;
    border-radius: var(--r-xl) var(--r-xl) 0 0;
    animation: sheet-in .25s var(--ease-out);
  }
  @keyframes sheet-in {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
  }
}

@media (max-width: 560px) {
  .sidebar-inner { padding: 10px 12px 8px; }
  .composer { padding: 6px; gap: 6px; }
  .composer textarea { padding: 6px 8px; font-size: 13.5px; }
  .send-btn { padding: 9px 13px; }
  .mic-btn { min-width: 40px; padding: 8px 10px; }
  .welcome h2 { font-size: 18px; }
  .welcome-flow { flex-direction: column; gap: 6px; }
  .welcome-flow i { width: 1px; height: 14px; }
  .welcome-examples { gap: 6px; }
}