/* ==================== Legacy Mode Styles ==================== */
/* body.legacy 时生效，还原旧版简洁 UI */

/* ===== 隐藏新版登录页（用 html.legacy 防止 FOUC） ===== */
html.legacy #login-page,
body.legacy #login-page {
    display: none !important;
}

/* ==================== 旧版登录页 ==================== */
#legacy-login-page {
    display: none;
}

html.legacy #legacy-login-page,
body.legacy #legacy-login-page {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: 20px;
}

.legacy-login-card {
    background: white;
    border-radius: var(--radius-xl);
    padding: 48px 40px;
    width: 100%;
    max-width: 440px;
    box-shadow: var(--shadow-xl);
    animation: legacyFadeInUp 0.5s ease;
}

@keyframes legacyFadeInUp {
    from { opacity: 0; transform: translateY(20px); }
    to   { opacity: 1; transform: translateY(0); }
}

.legacy-login-header {
    text-align: center;
    margin-bottom: 36px;
}

.legacy-login-header .logo-icon {
    display: flex;
    justify-content: center;
    margin-bottom: 16px;
}

.legacy-login-header h1 {
    font-size: 26px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.legacy-login-header p {
    font-size: 14px;
    color: var(--text-secondary);
}

/* 表单：复用 styles.css 中的 .form-group / .password-wrapper / .toggle-password
   / .form-options / .checkbox-label / .link-text / .btn-primary，
   只需在 #legacy-login-page 作用域内微调 */

#legacy-login-page .auth-form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

#legacy-login-page .btn-primary {
    padding: 13px 24px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    font-family: inherit;
    letter-spacing: 2px;
}

#legacy-login-page .btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.4);
}

#legacy-login-page .auth-switch {
    text-align: center;
    font-size: 14px;
    color: var(--text-secondary);
}

#legacy-login-page .auth-switch a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

#legacy-login-page .auth-switch a:hover {
    text-decoration: underline;
}

/* 旧版登录页底部按钮 */
.legacy-version-toggle {
    position: fixed;
    bottom: 24px;
    right: 24px;
    padding: 8px 18px;
    background: rgba(255, 255, 255, 0.18);
    color: #f1f5f9;
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 100px;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    transition: background 0.2s, transform 0.2s;
    z-index: 100;
}

.legacy-version-toggle:hover {
    background: rgba(255, 255, 255, 0.28);
    transform: translateY(-1px);
}

.legacy-about-toggle {
    position: fixed;
    bottom: 24px;
    left: 24px;
    padding: 8px 18px;
    background: rgba(255, 255, 255, 0.18);
    color: #f1f5f9;
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 100px;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    transition: background 0.2s, transform 0.2s;
    z-index: 100;
}

.legacy-about-toggle:hover {
    background: rgba(255, 255, 255, 0.28);
    transform: translateY(-1px);
}

/* ==================== 聊天页：白底黑字，移除毛玻璃/渐变/动画 ==================== */

/* 强制浅色 CSS 变量 — 覆盖 styles.css 第 2515 行的非限定 :root 暗色重定义 */
body.legacy {
    --bg-main: #f8f9fc;
    --bg-sidebar: #ffffff;
    --bg-message-ai: #ffffff;
    --text-primary: #1a1a2e;
    --text-secondary: #6b7280;
    --text-muted: #9ca3af;
    --border-color: #e5e7eb;
    --border-hover: #d1d5db;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
    --t-panel: #ffffff;
    --t-panel-soft: #f8f9fc;
    --t-glass: rgba(255, 255, 255, 0.9);
    --t-border: #e5e7eb;
    --t-border-strong: #d1d5db;
    --t-text: #1a1a2e;
    --t-text-soft: #6b7280;
    --t-accent: #6366f1;
    --t-accent-soft: rgba(99, 102, 241, 0.08);
}

/* 整体应用容器 */
body.legacy .chat-app {
    background: var(--bg-main) !important;
}

/* 主聊天区：纯色背景 */
body.legacy .chat-main {
    background: var(--bg-main) !important;
}

/* 聊天头部：白色背景，移除毛玻璃 */
body.legacy .chat-header {
    background: var(--bg-sidebar) !important;
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
    border-bottom: 1px solid var(--border-color) !important;
}

/* 输入区：白色背景，移除毛玻璃 */
body.legacy .chat-input-area {
    background: var(--bg-sidebar) !important;
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
    border-top: 1px solid var(--border-color) !important;
}

/* AI 消息气泡：纯白背景 */
body.legacy .message.ai .message-bubble {
    background: var(--bg-message-ai) !important;
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
    border: 1px solid var(--border-color) !important;
    box-shadow: var(--shadow-sm) !important;
}

/* 用户消息气泡：渐变背景（与旧版一致） */
body.legacy .message.user .message-bubble {
    background: var(--bg-message-user) !important;
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
    border: none !important;
    box-shadow: var(--shadow-sm) !important;
}

/* 侧边栏：白色背景 */
body.legacy .sidebar {
    background: var(--bg-sidebar) !important;
    border-right: 1px solid var(--border-color) !important;
}

/* 模态弹窗：白色背景 */
body.legacy .modal-card {
    background: white !important;
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
    border: 1px solid var(--border-color) !important;
}

body.legacy .modal-overlay {
    background: rgba(0, 0, 0, 0.4) !important;
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
}

body.legacy .modal-header {
    border-bottom: 1px solid var(--border-color) !important;
}

body.legacy .modal-header h3 {
    color: var(--text-primary) !important;
}

body.legacy .modal-body {
    color: var(--text-secondary) !important;
}

body.legacy .modal-body .form-group label {
    color: var(--text-secondary) !important;
}

body.legacy .modal-body .form-group input {
    background: white !important;
    border-color: var(--border-color) !important;
    color: var(--text-primary) !important;
}

body.legacy .modal-body .form-group input::placeholder {
    color: var(--text-muted) !important;
}

body.legacy .modal-footer {
    border-top: 1px solid var(--border-color) !important;
}

/* 次要按钮 */
body.legacy .btn-secondary {
    background: var(--bg-main) !important;
    color: var(--text-secondary) !important;
    border: 1px solid var(--border-color) !important;
}

body.legacy .btn-secondary:hover {
    background: var(--bg-main) !important;
    color: var(--text-primary) !important;
}

/* 知识库选择器菜单：白色背景 */
body.legacy .kb-selector-menu {
    background: white !important;
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
    border: 1px solid var(--border-color) !important;
    box-shadow: var(--shadow-lg) !important;
}

/* Toast：白色背景 */
body.legacy .toast {
    background: white !important;
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
    color: var(--text-primary) !important;
    box-shadow: var(--shadow-lg) !important;
}

/* ===== 以下为覆盖 styles.css 中非主题限定的暗色规则 ===== */

/* 输入框、搜索框：白色背景 */
body.legacy .form-group input {
    background: white !important;
    border: 1px solid var(--border-color) !important;
    color: var(--text-primary) !important;
}

body.legacy .form-group input:focus {
    border-color: var(--primary) !important;
}

body.legacy .search-box input {
    background: white !important;
    border: 1px solid var(--border-color) !important;
    color: var(--text-primary) !important;
}

body.legacy .search-box input:focus {
    background: white !important;
}

/* 输入框容器：白色背景 */
body.legacy .input-wrapper {
    background: white !important;
    border: 1px solid var(--border-color) !important;
}

body.legacy .input-box textarea {
    background: transparent !important;
    color: var(--text-primary) !important;
}

/* 图标按钮 */
body.legacy .btn-icon {
    background: transparent !important;
    border: 1px solid transparent !important;
    color: var(--text-secondary) !important;
}

body.legacy .btn-icon:hover {
    background: var(--bg-main) !important;
    color: var(--primary) !important;
}

/* 消息操作按钮 */
body.legacy .msg-action-btn {
    background: var(--bg-main) !important;
    border: 1px solid var(--border-color) !important;
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
    color: var(--text-secondary) !important;
}

/* 建议卡片 */
body.legacy .suggestion-card {
    background: white !important;
    border: 1px solid var(--border-color) !important;
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
    color: var(--text-primary) !important;
}

body.legacy .suggestion-card:hover {
    border-color: var(--primary) !important;
    background: var(--bg-main) !important;
}

/* AI 头像 */
body.legacy .message.ai .message-avatar {
    background: #f3f4f6 !important;
    color: var(--text-primary) !important;
}

/* 代码块背景 */
body.legacy .message-bubble code {
    background: var(--bg-main) !important;
    color: var(--text-primary) !important;
}

/* 消息内文件卡片 */
body.legacy .message-file {
    background: var(--bg-main) !important;
    border: 1px solid var(--border-color) !important;
}

body.legacy .message-file:hover {
    background: var(--bg-main) !important;
}

/* 表格斑马纹 */
body.legacy .md-table tbody tr:nth-child(even) {
    background: var(--bg-main) !important;
}

/* 对话历史项激活态 */
body.legacy .chat-history-item.active {
    background: rgba(99, 102, 241, 0.1) !important;
}

/* 知识库选择项 */
body.legacy .kb-selector-item:hover {
    background: var(--bg-main) !important;
}

/* 知识库上传区 */
body.legacy .kb-upload-area {
    background: var(--bg-main) !important;
    border-color: var(--border-color) !important;
}

/* 知识库文档项 / 已发送文件项 */
body.legacy .kb-doc-item,
body.legacy .sent-file-item {
    background: var(--bg-main) !important;
    border: 1px solid var(--border-color) !important;
}

body.legacy .kb-doc-item:hover,
body.legacy .sent-file-item:hover {
    background: var(--bg-main) !important;
}

body.legacy .kb-doc-info,
body.legacy .kb-doc-name,
body.legacy .sent-file-item * {
    color: var(--text-primary) !important;
}

body.legacy .kb-upload-hint {
    color: var(--text-muted) !important;
}

/* 图片预览弹窗 */
body.legacy .image-modal {
    background: rgba(0, 0, 0, 0.85) !important;
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
}

/* ==================== 关于弹窗：白底黑字 ==================== */
body.legacy .about-brand {
    border-bottom: 1px solid var(--border-color) !important;
}

body.legacy .about-slogan {
    color: var(--text-secondary) !important;
}

body.legacy .about-label {
    color: var(--text-secondary) !important;
}

body.legacy .about-value {
    color: var(--text-primary) !important;
}

body.legacy .about-note {
    background: rgba(167, 139, 250, 0.06) !important;
    border: 1px solid rgba(167, 139, 250, 0.15) !important;
    color: var(--text-secondary) !important;
}

/* ==================== 隐藏新版独有功能 ==================== */

/* 头像选择弹层 */
body.legacy .avatar-picker {
    display: none !important;
}

/* Tab 滑块动画 */
body.legacy .tab-slider {
    display: none;
}

/* 消息进入动画（旧版无动画） */
body.legacy .message {
    animation: none !important;
}

/* 侧边栏滑入动画 */
body.legacy .sidebar {
    transition: margin-left 0.3s ease;
}

/* 拖拽遮罩简化 */
body.legacy .drag-drop-overlay {
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
    background: rgba(99, 102, 241, 0.1) !important;
}

/* ==================== 简化用户头像（文字首字母） ==================== */

body.legacy .avatar-btn {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border: none;
}

body.legacy .avatar-btn:hover {
    border: none;
    transform: none;
    box-shadow: none;
}

body.legacy .avatar-btn .avatar-img {
    display: none;
}

body.legacy .avatar-btn::after {
    content: attr(data-initial);
    color: white;
    font-weight: 600;
    font-size: 16px;
    text-transform: uppercase;
}

/* ==================== 欢迎界面：SVG Logo 替代图片 ==================== */

body.legacy .welcome-visual {
    width: 80px;
    height: 80px;
    margin: 0 auto 24px;
    border-radius: 20px;
    overflow: visible;
    border: none;
    box-shadow: 0 8px 30px rgba(99, 102, 241, 0.25);
    display: flex;
    align-items: center;
    justify-content: center;
}

body.legacy .welcome-visual img {
    display: none;
}

body.legacy .welcome-visual::after {
    content: '';
    width: 64px;
    height: 64px;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='64' height='64' viewBox='0 0 48 48' fill='none'%3E%3Crect width='48' height='48' rx='12' fill='url(%23lg)'/%3E%3Cpath d='M24 12L36 18V30L24 36L12 30V18L24 12Z' stroke='white' stroke-width='2' fill='none'/%3E%3Ccircle cx='24' cy='24' r='4' fill='white'/%3E%3Cdefs%3E%3ClinearGradient id='lg' x1='0' y1='0' x2='48' y2='48'%3E%3Cstop stop-color='%236366f1'/%3E%3Cstop offset='1' stop-color='%238b5cf6'/%3E%3C/linearGradient%3E%3C/defs%3E%3C/svg%3E");
    background-size: contain;
    background-repeat: no-repeat;
    background-position: center;
}

body.legacy .welcome-screen h2 {
    font-size: 28px;
}

/* ==================== 版本切换按钮（聊天页侧边栏） ==================== */

.chat-version-toggle {
    background: none;
    border: 1px solid var(--border-color);
    border-radius: 100px;
    padding: 4px 12px;
    font-size: 12px;
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
}

.chat-version-toggle:hover {
    color: var(--primary);
    border-color: var(--primary);
}

/* ==================== 新版登录页底部切换按钮 ==================== */

.lp-version-toggle {
    position: fixed;
    bottom: 24px;
    right: 24px;
    padding: 8px 18px;
    background: rgba(255, 255, 255, 0.1);
    color: #cbd5e1;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 100px;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    transition: background 0.2s, transform 0.2s;
    z-index: 100;
}

.lp-version-toggle:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-1px);
}

/* ==================== 响应式 ==================== */

@media (max-width: 560px) {
    .legacy-login-card {
        padding: 32px 24px;
    }
}

@media (max-width: 380px) {
    .legacy-login-card {
        padding: 24px 20px;
    }
}