/* ===== CSS變數定義 ===== */
:root {
    /* 主色調 */
    --primary: #3b82f6;
    --primary-dark: #2563eb;
    --primary-light: #60a5fa;
    --secondary: #6366f1;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --info: #06b6d4;
    
    /* 中性色 */
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;
    
    /* 背景色 */
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-accent: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --bg-card: rgba(255, 255, 255, 0.95);
    --bg-overlay: rgba(0, 0, 0, 0.1);
    
    /* 陰影 */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.08);
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.12), 0 1px 2px 0 rgba(0, 0, 0, 0.08);
    --shadow-md: var(--shadow-sm);
    --shadow-lg: var(--shadow-sm);
    --shadow-xl: var(--shadow-sm);
    
    /* 圓角 */
    --radius-sm: 0.375rem;
    --radius: 0.5rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;
    
    /* 字體 */
    --font-family: 'Inter', 'Noto Sans TC', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    
    /* 間距 */
    --spacing-1: 0.25rem;
    --spacing-2: 0.5rem;
    --spacing-3: 0.75rem;
    --spacing-4: 1rem;
    --spacing-5: 1.25rem;
    --spacing-6: 1.5rem;
    --spacing-8: 2rem;
    --spacing-10: 2.5rem;
    --spacing-12: 3rem;
    
    /* 過渡動畫 */
    --transition-fast: 150ms ease-in-out;
    --transition-normal: 250ms ease-in-out;
    --transition-slow: 350ms ease-in-out;
}

/* ===== 全局樣式重置 ===== */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    /* 全域防止過度滾動 */
    overscroll-behavior: none;
    -webkit-overscroll-behavior: none;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
    /* 防止移動設備滾動閃爍 */
    -webkit-overflow-scrolling: touch;
    overflow-scrolling: touch;
    /* 防止移動設備過度滾動和橡皮筋效果 */
    overscroll-behavior: none;
    overscroll-behavior-y: none;
    overscroll-behavior-x: none;
    -webkit-overscroll-behavior: none;
    -webkit-overscroll-behavior-y: none;
    -webkit-overscroll-behavior-x: none;
    /* 防止邊界閃爍 */
    overflow: hidden;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--gray-700);
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 50%, #f1f5f9 100%);
    background-attachment: fixed; /* 固定背景防止滾動時重新渲染 */
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
    overflow-y: auto;
    min-height: 100vh;
    max-height: 100vh; /* 限制最大高度防止過度滾動 */
    position: relative;
    /* 移動設備優化 */
    -webkit-overflow-scrolling: touch;
    -webkit-transform: translate3d(0, 0, 0); /* 啟用硬體加速 */
    transform: translate3d(0, 0, 0);
    /* 防止橡皮筋效果 */
    overscroll-behavior: none;
    overscroll-behavior-y: none;
    -webkit-overscroll-behavior: none;
    -webkit-overscroll-behavior-y: none;
}

body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(45deg, rgba(59, 130, 246, 0.03) 0%, rgba(99, 102, 241, 0.03) 100%);
    pointer-events: none;
    z-index: -1;
}

/* ===== 主容器樣式 ===== */
.chat-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    position: relative;
    /* 移動設備優化 */
    -webkit-transform: translate3d(0, 0, 0);
    transform: translate3d(0, 0, 0);
    -webkit-overflow-scrolling: touch;
}

/* ===== 載入動畫覆蓋層 ===== */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    opacity: 0;
    transition: opacity 0.5s ease-out;
}

.loading-overlay.show {
    opacity: 1;
}

.loading-spinner {
    position: relative;
    width: 80px;
    height: 80px;
    margin-bottom: var(--spacing-6);
}

.spinner-ring {
    position: absolute;
    width: 64px;
    height: 64px;
    border: 8px solid transparent;
    border-top: 8px solid rgba(255, 255, 255, 0.8);
    border-radius: 50%;
    animation: spin 1.2s linear infinite;
}

.spinner-ring:nth-child(1) {
    animation-delay: -0.45s;
}

.spinner-ring:nth-child(2) {
    animation-delay: -0.3s;
}

.spinner-ring:nth-child(3) {
    animation-delay: -0.15s;
}

.loading-text {
    color: white;
    font-size: var(--font-size-lg);
    font-weight: 500;
    margin: 0;
    /* animation: pulse 2s ease-in-out infinite; */
}

/* ===== 資料夾選擇區域 ===== */
.form-group {
    padding: var(--spacing-2);
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    margin-left: var(--spacing-4);
    margin-right: var(--spacing-4);
    box-shadow: var(--shadow-lg);
    /* backdrop-filter: blur(20px); */
    border: 2px solid rgba(255, 255, 255, 0.8);
    position: sticky;
    top: 0;
    z-index: 100;
}

.form-group::before {
    content: '';
    position: sticky;
    top: 0;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.1) 0%, rgba(255, 255, 255, 0.05) 100%);
    pointer-events: none;
}

.form-label {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
    font-weight: 600;
    color: var(--gray-800);
    font-size: var(--font-size-base);
    position: relative;
    z-index: 1;
}

.form-label::before {
    content: '';
    width: 20px;
    height: 20px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
}

.form-label::after {
    content: '📁';
    position: absolute;
    left: 3px;
    font-size: 12px;
}

.folder-selector {
    display: none;
    gap: var(--spacing-2);
    flex-wrap: wrap;
    position: relative;
    z-index: 1;
}

.folder-selector.expanded {
    display: flex;
    animation: slideDown var(--transition-normal) ease-out;
    /* GPU優化：強制硬體加速 */
    -webkit-transform: translateZ(0);
    transform: translateZ(0);
    will-change: opacity, transform;
    /* 減少重繪區域 */
    contain: layout style paint;
}

.folder-pill {
    background: rgba(255, 255, 255, 0.8);
    padding: var(--spacing-1) var(--spacing-4);
    border-radius: var(--radius-xl);
    font-size: var(--font-size-sm);
    font-weight: 500;
    cursor: pointer;
    white-space: nowrap;
    /* GPU優化：只對必要屬性進行過渡 */
    transition: background-color var(--transition-fast), border-color var(--transition-fast), transform var(--transition-fast);
    border: 2px solid var(--gray-200);
    /* 強制GPU加速 */
    -webkit-transform: translateZ(0);
    transform: translateZ(0);
    will-change: background-color, border-color, transform;
    color: var(--gray-700);
    position: relative;
    overflow: hidden;
    margin-right: 10px;
}

.folder-pill::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    transition: left var(--transition-slow);
}

.folder-pill:hover::before {
    left: 100%;
}

.folder-pill:hover {
    background: rgba(59, 130, 246, 0.1);
    border-color: var(--primary-light);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.folder-pill.active {
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
    border-color: var(--primary);
    box-shadow: var(--shadow-lg);
    transform: scale(1.02);
}

/* ===== 對話區域樣式 ===== */
.chat-messages {
    flex: 1;
    overflow-y: auto;
    overflow-x: hidden;
    padding: var(--spacing-4);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-4);
    background: transparent; /* 移除背景避免重複渲染 */
    /* 移動設備滾動優化 */
    -webkit-overflow-scrolling: touch;
    -webkit-transform: translate3d(0, 0, 0);
    transform: translate3d(0, 0, 0);
    /* 防止邊界過度滾動 */
    overscroll-behavior: none;
    overscroll-behavior-y: none;
    -webkit-overscroll-behavior: none;
    -webkit-overscroll-behavior-y: none;
    /* 確保滾動邊界 */
    scroll-behavior: smooth !important;
}

.chat-messages::-webkit-scrollbar {
    width: 8px;
}

.chat-messages::-webkit-scrollbar-track {
    background: var(--gray-100);
    border-radius: var(--radius);
}

.chat-messages::-webkit-scrollbar-thumb {
    background: var(--gray-300);
    border-radius: var(--radius);
}

.chat-messages::-webkit-scrollbar-thumb:hover {
    background: var(--gray-400);
}

/* ===== 消息氣泡樣式 ===== */
.message-bubble {
    max-width: 80%;
    padding: var(--spacing-4) var(--spacing-5);
    border-radius: var(--radius-xl);
    position: relative;
    word-wrap: break-word;
    box-shadow: var(--shadow);
    /* backdrop-filter: blur(10px); */
    transition: all var(--transition-fast);
    animation: messageSlideIn var(--transition-normal) ease-out;
}

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

.user-message {
    align-self: flex-end;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
    border-bottom-right-radius: var(--radius-sm);
    position: relative;
}

.user-message::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.1) 0%, rgba(255, 255, 255, 0.05) 100%);
    pointer-events: none;
}

.assistant-message {
    align-self: flex-start;
    background: var(--bg-card);
    color: var(--gray-800);
    border-bottom-left-radius: var(--radius-sm);
    border: 2px solid rgba(59, 130, 246, 0.1);
}

.assistant-message::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
}

.message-bubble:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.message-time {
    font-size: var(--font-size-xs);
    color: rgba(255, 255, 255, 0.7);
    margin-top: var(--spacing-2);
    text-align: right;
    font-weight: 500;
}

.assistant-message .message-time {
    color: var(--gray-500);
}

.message-actions {
    position: absolute;
    top: var(--spacing-2);
    right: var(--spacing-2);
    opacity: 0;
    transition: opacity var(--transition-fast);
}

.message-content{
    padding-right: 20px;
    
}

.message-bubble:hover .message-actions {
    opacity: 1;
}

.delete-message {
    background: rgba(239, 68, 68, 0.1);
    border: none;
    color: var(--danger);
    cursor: pointer;
    font-size: var(--font-size-sm);
    padding: var(--spacing-1);
    border-radius: var(--radius-sm);
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.delete-message:hover {
    background: var(--danger);
    color: white;
    transform: scale(1.1);
}

/* ===== 資料夾標題區域 ===== */
.folder-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    flex-wrap: wrap;
    gap: var(--spacing-2);
}

/* ===== 聊天控制區域 ===== */
.chat-controls {
    margin: var(--spacing-1);
    display: flex;
    right: 0;
    top: 0;
    z-index: 2;
}

.clear-history {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
    background: rgba(239, 68, 68, 0.1);
    border: 2px solid var(--danger);
    color: var(--danger);
    cursor: pointer;
    font-size: var(--font-size-sm);
    font-weight: 500;
    padding: var(--spacing-1) var(--spacing-2);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
}

.clear-history:hover {
    background: var(--danger);
    color: white;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* ===== 輸入區域樣式 ===== */
.chat-input-container {
    position: sticky;
    bottom: 0;
    left: 0;
    right: 0;
    padding: var(--spacing-0) var(--spacing-4) var(--spacing-4) var(--spacing-4);
    border-top: 2px solid rgba(59, 130, 246, 0.1);
    background: var(--bg-card);
    /* backdrop-filter: blur(20px); */
    box-shadow: var(--shadow-xl);
    margin: 0;
    /* 移動設備優化 */
    -webkit-transform: translate3d(0, 0, 0);
    transform: translate3d(0, 0, 0);
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
}

.chat-input-wrapper {
    display: flex;
    gap: var(--spacing-3);
    align-items: flex-end;
    margin: 0 auto;
    position: relative;
}

.app-input {
    flex: 1;
    padding: var(--spacing-4);
    border: 2px solid var(--gray-200);
    border-radius: var(--radius-xl);
    resize: none;
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    background: rgba(255, 255, 255, 0.9);
    /* backdrop-filter: blur(10px); */
    transition: all var(--transition-fast);
    min-height: 56px;
    max-height: 120px;
    line-height: 1.5;
}

.app-input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
    background: var(--bg-primary);
}

.app-input::placeholder {
    color: var(--gray-400);
}

.app-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-4);
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
    border: none;
    border-radius: var(--radius-xl);
    cursor: pointer;
    font-weight: 600;
    transition: all var(--transition-fast);
    box-shadow: var(--shadow-md);
    min-width: 56px;
    height: 56px;
    position: relative;
    overflow: hidden;
}

.app-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left var(--transition-slow);
}

.app-btn:hover::before {
    left: 100%;
}

.app-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.app-btn:active {
    transform: translateY(0);
}

.app-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

.app-btn i {
    font-size: 1.1rem;
}

/* ===== 相似問題建議樣式 ===== */
.similar-questions {
    position: fixed;
    width: 100%;
    bottom: calc(var(--spacing-4) * 2 + 50px); /* 固定在輸入框上方 */
    background: var(--bg-card);
    border: 2px solid var(--primary);
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-md);
    overflow-y: hidden;
    overflow-x: hidden;
    display: none;
    z-index: 1001;
    /* backdrop-filter: blur(20px); */
    animation: suggestionsSlideUp var(--transition-normal) ease-out;
}

@keyframes suggestionsSlideUp {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.similar-questions::-webkit-scrollbar {
    width: 4px;
}

.similar-questions::-webkit-scrollbar-track {
    background: var(--gray-100);
    border-radius: var(--radius);
}

.similar-questions::-webkit-scrollbar-thumb {
    background: var(--gray-300);
    border-radius: var(--radius);
}

.similar-question-item {
    padding: var(--spacing-1);
    border-bottom: 1px solid rgba(59, 130, 246, 0.1);
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
    overflow: hidden;
}

.similar-question-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(59, 130, 246, 0.1), transparent);
    transition: left var(--transition-normal);
}

.similar-question-item:hover::before {
    left: 100%;
}

.similar-question-item:hover {
    background: rgba(59, 130, 246, 0.05);
    transform: translateX(5px);
}

.similar-question-item:last-child {
    border-bottom: none;
}

.similar-question-item .question {
    font-weight: 500;
    margin-bottom: var(--spacing-1);
    color: var(--gray-800);
    line-height: 1.4;
    position: relative;
    z-index: 1;
}

.similar-question-item .meta {
    font-size: var(--font-size-sm);
    color: var(--gray-500);
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
    position: relative;
    z-index: 1;
}

.similar-question-item .badge {
    font-size: var(--font-size-xs);
    border-radius: var(--radius);
    padding: 2px 8px;
    background: var(--gray-200);
    color: var(--gray-600);
    font-weight: 500;
}

.similar-question-item .badge.bg-info {
    background: var(--primary);
    color: white;
}

/* ===== 回答區域樣式 ===== */
.answer-container {
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    padding: var(--spacing-6);
    margin: var(--spacing-4);
    border-left: 4px solid var(--primary);
    box-shadow: var(--shadow-lg);
    /* backdrop-filter: blur(20px); */
    border: 2px solid rgba(59, 130, 246, 0.2);
    position: relative;
    overflow: hidden;
}

.answer-container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.1) 0%, rgba(255, 255, 255, 0.05) 100%);
    pointer-events: none;
}

#chat-answer {
    position: relative;
    z-index: 1;
    line-height: 1.7;
}

#chat-answer h1, #chat-answer h2, #chat-answer h3, 
#chat-answer h4, #chat-answer h5, #chat-answer h6 {
    color: var(--gray-800);
    font-weight: 600;
    margin-top: var(--spacing-6);
    margin-bottom: var(--spacing-3);
}

#chat-answer p {
    margin-bottom: var(--spacing-4);
    color: var(--gray-700);
}

#chat-answer ul, #chat-answer ol {
    margin-left: var(--spacing-6);
    margin-bottom: var(--spacing-4);
}

#chat-answer li {
    margin-bottom: var(--spacing-2);
    color: var(--gray-700);
}

#chat-answer a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
    transition: color var(--transition-fast);
}

#chat-answer a:hover {
    color: var(--primary-dark);
    text-decoration: underline;
}

#chat-answer code {
    background: var(--gray-100);
    color: var(--gray-800);
    padding: 2px 6px;
    border-radius: var(--radius-sm);
    font-family: 'Courier New', monospace;
    font-size: 0.9em;
}

#chat-answer pre {
    background: var(--gray-100);
    padding: var(--spacing-4);
    border-radius: var(--radius-md);
    overflow-x: auto;
    margin-bottom: var(--spacing-4);
}

#chat-answer blockquote {
    border-left: 4px solid var(--primary);
    margin: var(--spacing-4) 0;
    padding-left: var(--spacing-4);
    font-style: italic;
    color: var(--gray-600);
}

/* ===== 提示訊息樣式 ===== */
.small.text-muted {
    align-items: center;
    gap: var(--spacing-2);
    text-align: center; 
}

.small.text-muted i {
    color: var(--warning);
    font-size: 1.1em;
}

/* ===== Toast 通知樣式 ===== */
.toast {
    border: none;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    /* backdrop-filter: blur(20px); */
    background: var(--bg-card);
    overflow: hidden;
}

.toast-header {
    background: linear-gradient(135deg, rgba(239, 68, 68, 0.1) 0%, rgba(220, 38, 38, 0.1) 100%);
    border-bottom: 1px solid rgba(239, 68, 68, 0.2);
    border-radius: var(--radius-lg) var(--radius-lg) 0 0;
    font-weight: 600;
}

.toast-body {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 0 0 var(--radius-lg) var(--radius-lg);
    color: var(--gray-700);
}

/* ===== 載入動畫 ===== */
.loading-spinner {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-2);
    color: var(--primary);
}

.spinner {
    width: 16px;
    height: 16px;
    border: 2px solid var(--gray-200);
    border-top: 2px solid var(--primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

.folder-toggle {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-1) var(--spacing-2);
    background: rgba(255, 255, 255, 0.9);
    border: 2px solid var(--gray-200);
    border-radius: var(--radius-xl);
    cursor: pointer;
    /* GPU優化：只對必要屬性進行過渡 */
    transition: background-color var(--transition-fast), border-color var(--transition-fast);
    /* 強制GPU加速 */
    -webkit-transform: translateZ(0);
    transform: translateZ(0);
    will-change: background-color, border-color;
}

.folder-toggle:hover {
    background: rgba(59, 130, 246, 0.1);
    border-color: var(--primary-light);
}

.current-folder-text {
    font-weight: 500;
    color: var(--gray-700);
}

.toggle-icon {
    transition: transform var(--transition-fast);
    color: var(--primary);
}

.folder-toggle.expanded .toggle-icon {
    transform: rotate(180deg);
}


/* GPU優化：使用transform3d強制硬體加速 */
@keyframes slideDown {
    from {
        opacity: 0;
        transform: translate3d(0, -10px, 0);
    }
    to {
        opacity: 1;
        transform: translate3d(0, 0, 0);
    }
}

/* ===== 響應式設計 ===== */
@media (max-width: 768px) {
    .folder-selector {
        gap: var(--spacing-1);
    }
    
    .chat-messages {
        /* 移動設備滾動容器設定 */
        overscroll-behavior: none !important;
        overscroll-behavior-y: none !important;
        -webkit-overscroll-behavior: none !important;
        -webkit-overscroll-behavior-y: none !important;
        /* 使用momentum scrolling但防止bounce */
        -webkit-overflow-scrolling: touch;
        /* 確保邊界處理 */
        scroll-padding-top: 0;
        scroll-padding-bottom: 0;
    }
    
    .folder-pill {
        padding: var(--spacing-2) var(--spacing-3);
        font-size: var(--font-size-xs);
        margin-right: 10px;
    }
    
    .message-bubble {
        max-width: 90%;
        padding: var(--spacing-3) var(--spacing-4);
    }
    
    .chat-input-container {
        padding: var(--spacing-3);
        position: sticky;
        bottom: 0;
    }
    
    .chat-input-wrapper {
        gap: var(--spacing-2);
    }
    
    .app-input {
        padding: var(--spacing-3);
        min-height: 48px;
    }
    
    .app-btn {
        min-width: 48px;
        height: 48px;
        padding: var(--spacing-3);
    }
    
    .similar-questions {
        left: var(--spacing-3);
        right: calc(var(--spacing-3) + 60px);
        bottom: calc(var(--spacing-3) * 2 + 70px);
    }
    
    .answer-container {
        margin: var(--spacing-2);
        padding: var(--spacing-4);
    }
    
    .small.text-muted {
        margin: var(--spacing-2);
        font-size: var(--font-size-xs);
    }

    .disclaimer-message {
        font-size: 12px;
        color: var(--gray-500);
        text-align: center;
        border-radius: var(--radius);
    }

    .tutorial-btn {
        font-size: 12px;
    }
    .clear-history {
        font-size: 12px;
    }
}

@media (max-width: 480px) {
    /* 極小螢幕額外優化 */
    body {
        /* 確保背景穩定 */
        background-attachment: scroll;
        background-color: #f1f5f9;
        /* 強制禁用橡皮筋效果 */
        overscroll-behavior: none !important;
        overscroll-behavior-y: none !important;
        overscroll-behavior-x: none !important;
        -webkit-overscroll-behavior: none !important;
        -webkit-overscroll-behavior-y: none !important;
        -webkit-overscroll-behavior-x: none !important;
        /* 極小螢幕強制隱藏溢出 */
        /* 禁用Safari bounce */
        -webkit-overflow-scrolling: auto;
    }
    
    .chat-messages {
        /* 極小螢幕滾動設定 */
        overscroll-behavior: none !important;
        -webkit-overscroll-behavior: none !important;
        -webkit-overflow-scrolling: touch;
    }
    
    .folder-pill {
        padding: var(--spacing-1) var(--spacing-2);
        font-size: 11px;
        margin-right: 10px;
    }
    
    .message-bubble {
        max-width: 95%;
        padding: var(--spacing-2) var(--spacing-3);
    }
    
    .chat-input-container {
        padding: var(--spacing-2);
    }
    
    .chat-input-wrapper {
        gap: var(--spacing-2);
    }
    
    .similar-questions {
        left: var(--spacing-2);
        right: var(--spacing-2);
        bottom: calc(var(--spacing-2) * 2 + 100px);
    }
    
    .small.text-muted {
        font-size: 12px;
    }
    
    .folder-header {
        flex-direction: column;
        align-items: stretch;
        gap: var(--spacing-3);
    }
    
    .disclaimer-message {
        font-size: 10px;
        color: var(--gray-500);
        text-align: center;
        border-radius: var(--radius);
    }

    .form-group {
        font-size: 12px;
    }

    .tutorial-btn {
        font-size: 12px;
    }
    .clear-history {
        font-size: 12px;
    }
}

/* ===== 動畫效果 ===== */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn var(--transition-normal) ease-out;
}

.slide-in-up {
    animation: slideInUp var(--transition-normal) ease-out;
}

/* ===== 無障礙設計 ===== */
*:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
    border-radius: var(--radius-sm);
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* ===== 高對比度模式 ===== */
@media (prefers-contrast: high) {
    :root {
        --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
        --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.4);
        --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
        --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4);
        --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.4);
    }
    
    .folder-pill, .message-bubble, .similar-question-item {
        border-width: 2px;
    }
}

/* ===== 減少動畫模式 ===== */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* ===== 隱藏 reCAPTCHA badge ===== */
.grecaptcha-badge {
    display: none !important;
}

/* ===== 移動設備邊界防護 ===== */
@media (max-width: 768px) {
    /* 為移動設備添加額外的邊界保護 */
    body::after {
        content: '';
        position: fixed;
        top: -100px;
        left: 0;
        right: 0;
        height: 100px;
        background: #f1f5f9;
        z-index: -2;
        pointer-events: none;
    }
    
    body::before {
        bottom: -100px;
        top: auto;
        height: 100px;
        background: #f1f5f9;
    }
    
    /* 確保滾動容器的邊界處理 */
    .chat-messages::before {
        content: '';
        position: sticky;
        top: -10px;
        display: block;
        height: 10px;
        background: #f1f5f9;
        margin: 0 -20px;
        z-index: 10;
    }
    
    .chat-messages::after {
        content: '';
        position: sticky;
        bottom: -10px;
        display: block;
        height: 10px;
        background: #f1f5f9;
        margin: 0 -20px;
        z-index: 10;
    }
}

 .feedback-buttons {
    margin-top: var(--spacing-3);
    display: flex;
    gap: var(--spacing-2);
}

.feedback-btn {
    background: transparent;
    border: 1px solid var(--gray-300);
    color: var(--gray-600);
    padding: var(--spacing-1) var(--spacing-2);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: var(--font-size-sm);
}

.feedback-btn:hover {
    transform: translateY(-1px);
}

.feedback-btn.helpful:hover {
    background: rgba(16, 185, 129, 0.1);
    border-color: var(--success);
    color: var(--success);
}

.feedback-btn.unhelpful:hover {
    background: rgba(239, 68, 68, 0.1);
    border-color: var(--danger);
    color: var(--danger);
}

.feedback-btn i {
    margin-right: var(--spacing-1);
}
 /* 歡迎訊息樣式 */
 .welcome-message {
    display: none;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 3rem 2rem;
    color: var(--gray-600);
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    margin: var(--spacing-4);
    box-shadow: var(--shadow-lg);
    /* backdrop-filter: blur(20px); */
    border: 2px solid rgba(255, 255, 255, 0.8);
    position: relative;
    overflow: hidden;
}

.welcome-message::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.1) 0%, rgba(255, 255, 255, 0.05) 100%);
    pointer-events: none;
}

.welcome-icon {
    position: relative;
    z-index: 1;
    margin-bottom: var(--spacing-4);
}

.welcome-icon i {
    font-size: 3rem;
    color: var(--primary);
    animation: float 3s ease-in-out infinite;
}

.welcome-message h4 {
    color: var(--gray-800);
    font-weight: 700;
    margin-bottom: var(--spacing-3);
    position: relative;
    z-index: 1;
}

.welcome-message p {
    color: var(--gray-600);
    margin: 0;
    position: relative;
    z-index: 1;
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-10px); }
}

/* 響應式調整 */
@media (max-width: 768px) {
    .welcome-message {
        margin: var(--spacing-2);
        padding: var(--spacing-6) var(--spacing-4);
    }
    
    .welcome-icon i {
        font-size: 2.5rem;
    }
    
    .welcome-message h4 {
        font-size: var(--font-size-xl);
    }
}

/* 教學模態框樣式 */
.tutorial-hint {
    animation: tutorialPulse 2s infinite;
    position: relative;
}

@keyframes tutorialPulse {
    0% {
        box-shadow: 0 0 0 0 rgba(59, 130, 246, 0.7);
    }
    70% {
        box-shadow: 0 0 0 10px rgba(59, 130, 246, 0);
    }
    100% {
        box-shadow: 0 0 0 0 rgba(59, 130, 246, 0);
    }
}

.guided-tutorial {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 10000;
    pointer-events: none;
}

.tutorial-backdrop {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0);
    pointer-events: all;
}

.tutorial-spotlight {
    position: absolute;
    background: rgba(59, 130, 246, 0.1);
    border: 3px solid #3b82f6;
    border-radius: 8px;
    box-shadow: 0 0 0 9999px rgba(0, 0, 0, 0.6);
    transition: all 0.3s ease;
    pointer-events: none;
}

.tutorial-card {
    position: absolute;
    width: 350px;
    max-width: 90vw;
    background: white;
    border-radius: 12px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
    pointer-events: all;
    transition: all 0.3s ease;
    z-index: 10001;
}

.tutorial-card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    border-bottom: 1px solid #e5e7eb;
}

.tutorial-progress-info {
    display: flex;
    align-items: center;
    gap: 12px;
    flex: 1;
}

.tutorial-progress-bar {
    flex: 1;
    height: 4px;
    background: #e5e7eb;
    border-radius: 2px;
    overflow: hidden;
}

.tutorial-progress-fill {
    height: 100%;
    background: #3b82f6;
    transition: width 0.3s ease;
}

.tutorial-close-btn {
    background: none;
    border: none;
    color: #6b7280;
    font-size: 20px;
    cursor: pointer;
    padding: 4px;
    border-radius: 4px;
    transition: background-color 0.2s;
}

.tutorial-close-btn:hover {
    background: #f3f4f6;
    color: #374151;
}

.tutorial-card-body {
    padding: 20px;
    text-align: center;
}

.tutorial-icon {
    margin-bottom: 16px;
}

.tutorial-icon i {
    font-size: 32px;
    color: #3b82f6;
}

.tutorial-card h4 {
    margin-bottom: 12px;
    color: #1f2937;
    font-weight: 600;
}

.tutorial-card p {
    color: #6b7280;
    line-height: 1.5;
    margin: 0;
}

.tutorial-card-footer {
    display: flex;
    justify-content: space-between;
    padding: 16px 20px;
    border-top: 1px solid #e5e7eb;
    gap: 12px;
}

.tutorial-btn {
    padding: var(--spacing-1);
    border-radius: 6px;
    border: none;
    cursor: pointer;
    font-weight: 500;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    gap: var(--spacing-1);
}

.tutorial-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.tutorial-btn-secondary {
    background: #f3f4f6;
    color: #374151;
}

.tutorial-btn-secondary:hover:not(:disabled) {
    background: #e5e7eb;
}

.tutorial-btn-primary {
    background: #3b82f6;
    color: white;
}

.tutorial-btn-primary:hover:not(:disabled) {
    background: #2563eb;
}

.tutorial-btn-success {
    background: #10b981;
    color: white;
}

.tutorial-btn-success:hover:not(:disabled) {
    background: #059669;
}

.disclaimer-content {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-1);
    padding: var(--spacing-1);
    position: relative;
}

.disclaimer-message {
    font-size: 12px;
    margin-bottom: 0;
}

/* ===== Accordion收折GPU性能優化 ===== */

/* 1. 優化所有過渡動畫元素 */
.folder-toggle,
.folder-pill,
.toggle-icon,
.similar-questions {
    /* 強制GPU加速 */
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    -webkit-perspective: 1000;
    perspective: 1000;
}

/* 2. 手機端動畫簡化 */
@media (max-width: 768px) {
    .folder-selector.expanded {
        /* 簡化動畫以提升性能 */
        animation: none !important;
        transition: opacity 0.2s ease-out;
    }
    
    .folder-toggle,
    .folder-pill {
        /* 減少過渡時間 */
        transition-duration: 0.15s !important;
    }
    
    /* 禁用複雜的hover效果 */
    .folder-toggle:hover,
    .folder-pill:hover {
        transform: none !important;
    }
}

/* 3. 低性能設備優化 */
@media (max-width: 768px) and (max-resolution: 150dpi) {
    /* 完全禁用動畫 */
    .folder-selector.expanded,
    .folder-toggle,
    .folder-pill,
    .toggle-icon {
        animation: none !important;
        transition: none !important;
    }
}

/* 4. 減少動畫模式優化 */
@media (prefers-reduced-motion: reduce) {
    .folder-selector.expanded {
        animation: none !important;
    }
    
    .toggle-icon {
        transition: none !important;
    }
    
    @keyframes slideDown {
        from, to {
            transform: translate3d(0, 0, 0);
            opacity: 1;
        }
    }
}

/* 5. 容器優化 - 減少重繪範圍 */
.form-group,
.chat-messages,
.chat-input-container {
    contain: layout style;
}

/* 6. 特殊性能優化 - 針對收折動作 */
.folder-selector {
    /* 防止佈局抖動 */
    min-height: 0;
    overflow: hidden;
}

.folder-selector.expanded {
    /* 優化展開動畫 */
    animation-fill-mode: forwards;
    animation-timing-function: cubic-bezier(0.25, 0.46, 0.45, 0.94);
}