/* ===========================================
   AI Database Assistant - Modern Professional UI
   2025 Design System
   =========================================== */

/* CSS Variables - Modern Color Palette */
:root {
    /* Primary Brand Colors - Deep Blue/Purple Gradient */
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    
    /* Secondary Colors */
    --secondary: #8b5cf6;
    --accent: #ec4899;
    --success: #10b981;
    --error: #ef4444;
    --warning: #f59e0b;
    --info: #3b82f6;
    
    /* Neutral Grays - Enhanced */
    --white: #ffffff;
    --gray-50: #f8fafc;
    --gray-100: #f1f5f9;
    --gray-200: #e2e8f0;
    --gray-300: #cbd5e1;
    --gray-400: #94a3b8;
    --gray-500: #64748b;
    --gray-600: #475569;
    --gray-700: #334155;
    --gray-800: #1e293b;
    --gray-900: #0f172a;
    
    /* Background Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --bg-dark: #0f172a;
    --bg-overlay: rgba(15, 23, 42, 0.5);
    
    /* Gradient Backgrounds */
    --bg-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --bg-gradient-subtle: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
    
    /* Spacing System */
    --space-xs: 0.25rem;    /* 4px */
    --space-sm: 0.5rem;     /* 8px */
    --space-md: 1rem;       /* 16px */
    --space-lg: 1.5rem;     /* 24px */
    --space-xl: 2rem;       /* 32px */
    --space-2xl: 3rem;      /* 48px */
    --space-3xl: 4rem;      /* 64px */
    
    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica', 'Arial', sans-serif;
    --font-mono: 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', monospace;
    
    --text-xs: 0.75rem;     /* 12px */
    --text-sm: 0.875rem;    /* 14px */
    --text-base: 1rem;      /* 16px */
    --text-lg: 1.125rem;    /* 18px */
    --text-xl: 1.25rem;     /* 20px */
    --text-2xl: 1.5rem;     /* 24px */
    --text-3xl: 1.875rem;   /* 30px */
    
    /* Border Radius - Modern Curves */
    --radius-sm: 0.5rem;    /* 8px */
    --radius-md: 0.75rem;   /* 12px */
    --radius-lg: 1rem;      /* 16px */
    --radius-xl: 1.5rem;    /* 24px */
    --radius-full: 9999px;
    
    /* Shadows - Layered Depth */
    --shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px -1px rgba(0, 0, 0, 0.1);
    --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);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    --shadow-glow: 0 0 15px rgba(102, 126, 234, 0.4);
    
    /* Transitions - Smooth Animations */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
    
    /* Z-index Layers */
    --z-base: 0;
    --z-dropdown: 1000;
    --z-sticky: 1100;
    --z-fixed: 1200;
    --z-modal-backdrop: 1300;
    --z-modal: 1400;
    --z-popover: 1500;
    --z-tooltip: 1600;
}

/* ===========================================
   Base Styles & Resets
   =========================================== */

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

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

body {
    font-family: var(--font-sans);
    font-size: var(--text-base);
    line-height: 1.6;
    color: var(--gray-800);
    background: var(--bg-secondary);
    overflow-x: hidden;
}

/* ===========================================
   Loading Screen - Modern Spinner
   =========================================== */

.loading-screen {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: var(--z-modal);
    transition: opacity var(--transition-base), visibility var(--transition-base);
}

.loading-screen.hidden {
    opacity: 0;
    visibility: hidden;
}

.loading-spinner {
    width: 60px;
    height: 60px;
    border: 4px solid rgba(255, 255, 255, 0.2);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

.loading-screen p {
    margin-top: var(--space-lg);
    color: white;
    font-size: var(--text-lg);
    font-weight: 500;
    letter-spacing: 0.5px;
}

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

/* ===========================================
   Auth Screen - Modern Glassmorphism
   =========================================== */

.auth-screen {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-lg);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    position: relative;
    overflow: hidden;
}

/* Animated background shapes */
.auth-screen::before {
    content: '';
    position: absolute;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(255,255,255,0.1) 0%, transparent 70%);
    border-radius: 50%;
    top: -250px;
    right: -250px;
    animation: float 20s ease-in-out infinite;
}

.auth-screen::after {
    content: '';
    position: absolute;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(255,255,255,0.08) 0%, transparent 70%);
    border-radius: 50%;
    bottom: -200px;
    left: -200px;
    animation: float 15s ease-in-out infinite reverse;
}

@keyframes float {
    0%, 100% { transform: translate(0, 0) rotate(0deg); }
    50% { transform: translate(30px, 30px) rotate(180deg); }
}

.auth-container {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-2xl);
    padding: var(--space-2xl);
    width: 100%;
    max-width: 440px;
    position: relative;
    z-index: 1;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.auth-header {
    text-align: center;
    margin-bottom: var(--space-2xl);
}

.auth-header .logo {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 64px;
    height: 64px;
    background: var(--bg-gradient);
    border-radius: var(--radius-lg);
    margin-bottom: var(--space-lg);
    box-shadow: var(--shadow-lg);
}

.auth-header .logo svg {
    color: white;
}

.auth-header h1 {
    font-size: var(--text-3xl);
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: var(--space-sm);
    letter-spacing: -0.5px;
}

.auth-header .subtitle {
    font-size: var(--text-base);
    color: var(--gray-600);
    font-weight: 400;
}

.auth-form h2 {
    font-size: var(--text-2xl);
    font-weight: 600;
    color: var(--gray-900);
    margin-bottom: var(--space-xl);
}

.form-group {
    margin-bottom: var(--space-lg);
}

.form-group label {
    display: block;
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--gray-700);
    margin-bottom: var(--space-sm);
}

.form-group input {
    width: 100%;
    min-height: 44px;
    padding: 12px var(--space-md);
    font-size: var(--text-base);
    border: 2px solid var(--gray-200);
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
    background: white;
    font-family: var(--font-sans);
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.1);
}

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

.error-message {
    background: #fef2f2;
    border: 1px solid #fecaca;
    color: #dc2626;
    padding: var(--space-md);
    border-radius: var(--radius-md);
    font-size: var(--text-sm);
    margin-bottom: var(--space-lg);
}

.error-message.hidden {
    display: none;
}

/* Modern Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    min-height: 44px;
    padding: 12px var(--space-xl);
    font-size: var(--text-base);
    font-weight: 600;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-base);
    font-family: var(--font-sans);
    text-decoration: none;
    position: relative;
    overflow: hidden;
}

.btn::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 0.5s;
}

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

.btn-primary {
    background: var(--bg-gradient);
    color: white;
    box-shadow: var(--shadow-md);
}

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

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

.btn-block {
    width: 100%;
}

.btn-loading .btn-text {
    display: none;
}

.btn-loading .btn-loading-text {
    display: block;
}

.btn .btn-loading-text {
    display: none;
}

.auth-switch {
    text-align: center;
    margin-top: var(--space-xl);
    font-size: var(--text-sm);
    color: var(--gray-600);
}

.auth-switch a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 600;
    transition: color var(--transition-base);
}

.auth-switch a:hover {
    color: var(--primary-dark);
    text-decoration: underline;
}

/* ===========================================
   Chat Application - Modern Layout
   =========================================== */

.chat-app {
    display: flex;
    height: 100vh;
    background: var(--bg-secondary);
}

.chat-app.hidden {
    display: none;
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
    display: none;
    position: fixed;
    top: var(--space-sm);
    left: var(--space-sm);
    z-index: var(--z-fixed);
    min-width: 48px;
    min-height: 48px;
    width: 48px;
    height: 48px;
    background: white;
    border: none;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    cursor: pointer;
    align-items: center;
    justify-content: center;
    color: var(--gray-700);
    transition: all var(--transition-base);
}

.mobile-menu-toggle:hover {
    background: var(--gray-50);
    transform: scale(1.05) translateY(0);
}

@media (max-width: 768px) {
    .mobile-menu-toggle {
        display: flex;
    }
}

/* ===========================================
   Sidebar - Modern Glassmorphism
   =========================================== */

.sidebar {
    width: 280px;
    background: white;
    border-right: 1px solid var(--gray-200);
    display: flex;
    flex-direction: column;
    position: relative;
    z-index: var(--z-sticky);
    box-shadow: var(--shadow-sm);
    transition: width var(--transition-base), transform var(--transition-base);
}

.sidebar.collapsed {
    width: 60px;
    overflow: visible;
}

.sidebar.collapsed .sidebar-title {
    display: none;
}

.sidebar.collapsed .conversations-list {
    display: none;
}

.sidebar.collapsed .conversations-indicator {
    display: flex;
}

.sidebar.collapsed .user-details {
    display: none;
}

.sidebar.collapsed .sidebar-header {
    justify-content: center;
    padding-left: 14px;
    padding-right: 14px;
    position: relative;
}

.sidebar.collapsed .sidebar-footer {
    justify-content: center;
    padding-left: 14px;
    padding-right: 14px;
}

.sidebar.collapsed .new-chat-btn {
    width: 44px !important;
    height: 44px !important;
    min-width: 44px !important;
    min-height: 44px !important;
    opacity: 1 !important;
    visibility: visible !important;
    display: flex !important;
    position: static !important;
    margin: 0 !important;
    flex-shrink: 0 !important;
}

.sidebar.collapsed .new-chat-btn svg {
    width: 18px;
    height: 18px;
}

.sidebar.collapsed .user-info {
    justify-content: center;
    width: auto;
    display: flex !important;
}

.sidebar.collapsed .user-avatar {
    width: 44px !important;
    height: 44px !important;
    opacity: 1 !important;
    visibility: visible !important;
    display: flex !important;
    flex-shrink: 0;
}

.sidebar.collapsed .logout-btn-sidebar {
    display: none;
}

.sidebar.collapsed .user-avatar svg {
    width: 18px;
    height: 18px;
}

/* Sidebar Collapse Button - Modern Design */
.sidebar-collapse-btn {
    position: absolute;
    top: 130px; /* Positioned below the header to avoid overlapping with + button */
    right: -22px;
    min-width: 44px;
    min-height: 44px;
    width: 44px;
    height: 44px;
    background: white;
    border: 2px solid var(--gray-200);
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--gray-600);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
    z-index: 10;
}

/* Mobile Sidebar Close Button - Modern Professional Style */
.mobile-sidebar-close {
    display: none;
    position: absolute;
    top: var(--space-lg);
    right: -20px; /* Half outside sidebar */
    min-width: 40px;
    min-height: 40px;
    width: 40px;
    height: 40px;
    background: var(--gray-100);
    border: 2px solid white;
    border-radius: var(--radius-full);
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--gray-700);
    transition: all var(--transition-base);
    z-index: 100;
    opacity: 0;
    pointer-events: none;
    box-shadow: var(--shadow-md);
}

/* Only show when sidebar is open on mobile */
.sidebar.open .mobile-sidebar-close {
    opacity: 1;
    pointer-events: auto;
}

.sidebar-collapse-btn:hover {
    background: var(--bg-gradient);
    color: white;
    border-color: transparent;
    transform: scale(1.1);
    box-shadow: var(--shadow-lg);
}

.mobile-sidebar-close:hover {
    background: var(--gray-200);
    color: var(--gray-900);
    box-shadow: var(--shadow-lg);
}

.mobile-sidebar-close:active {
    background: var(--gray-300);
    transform: scale(0.95);
}

.mobile-sidebar-close svg {
    width: 20px;
    height: 20px;
    stroke-width: 2.5;
}

.sidebar-collapse-btn svg {
    transition: transform var(--transition-base);
}

.sidebar.collapsed .sidebar-collapse-btn svg {
    transform: rotate(180deg);
}

.sidebar-header {
    padding: var(--space-xl) var(--space-lg);
    border-bottom: 1px solid var(--gray-200);
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.05) 0%, rgba(118, 75, 162, 0.05) 100%);
    height: 104px;
    box-sizing: border-box;
    transition: padding var(--transition-base);
    position: relative;
}

.sidebar-title {
    font-size: var(--text-lg);
    font-weight: 600;
    color: var(--gray-900);
    letter-spacing: -0.3px;
}

.new-chat-btn {
    min-width: 44px;
    min-height: 44px;
    width: 44px;
    height: 44px;
    background: var(--bg-gradient);
    border: none;
    border-radius: var(--radius-md);
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-base);
    box-shadow: var(--shadow-sm);
}

.new-chat-btn:hover {
    transform: scale(1.1) rotate(90deg);
    box-shadow: var(--shadow-md);
}

/* Conversations List */
.conversations-list {
    flex: 1;
    overflow-y: auto;
    padding: var(--space-sm);
}

/* Conversations Indicator (for collapsed state) */
.conversations-indicator {
    display: none;
    justify-content: center;
    align-items: center;
    flex: 1;
    padding: 0;
}

.edit-history-btn {
    min-width: 44px;
    min-height: 44px;
    width: 44px;
    height: 44px;
    background: var(--bg-gradient);
    border: none;
    border-radius: var(--radius-md);
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-base);
    box-shadow: var(--shadow-sm);
}

.edit-history-btn:hover {
    transform: scale(1.1);
    box-shadow: var(--shadow-md);
}

.edit-history-btn svg {
    width: 18px;
    height: 18px;
}

.conversations-list::-webkit-scrollbar {
    width: 6px;
}

.conversations-list::-webkit-scrollbar-track {
    background: transparent;
}

.conversations-list::-webkit-scrollbar-thumb {
    background: var(--gray-300);
    border-radius: 3px;
}

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

.conversation-item {
    padding: var(--space-md);
    margin-bottom: var(--space-xs);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-base);
    border: 1px solid transparent;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-sm);
}

.conversation-item:hover {
    background: var(--gray-50);
    border-color: var(--gray-200);
    transform: translateX(4px);
}

.conversation-item.active {
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.1) 0%, rgba(118, 75, 162, 0.1) 100%);
    border-color: var(--primary-light);
    box-shadow: var(--shadow-xs);
}

.conversation-content {
    flex: 1;
    min-width: 0;
}

.conversation-title {
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--gray-900);
    margin-bottom: var(--space-xs);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.conversation-time {
    font-size: var(--text-xs);
    color: var(--gray-500);
}

.conversation-delete-btn {
    min-width: 44px;
    min-height: 44px;
    width: 44px;
    height: 44px;
    background: transparent;
    border: 1px solid transparent;
    border-radius: var(--radius-sm);
    color: var(--gray-500);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-base);
    opacity: 0.6;
    flex-shrink: 0;
}

.conversation-item:hover .conversation-delete-btn {
    opacity: 1;
}

.conversation-delete-btn:hover {
    background: var(--error);
    color: white;
    border-color: var(--error);
    transform: scale(1.1);
}

/* Sidebar Footer - User Profile */
.sidebar-footer {
    padding: var(--space-xl) var(--space-lg);
    border-top: 1px solid var(--gray-200);
    background: var(--gray-50);
    height: 136px;
    box-sizing: border-box;
    display: flex;
    align-items: center;
    transition: padding var(--transition-base);
}

.user-info {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    width: 100%;
}

.user-avatar {
    width: 40px;
    height: 40px;
    background: var(--bg-gradient);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    flex-shrink: 0;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
}

.user-details {
    flex: 1;
    min-width: 0;
}

.user-name {
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--gray-900);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.user-stats {
    font-size: var(--text-xs);
    color: var(--gray-600);
}

.logout-btn-sidebar {
    min-width: 44px;
    min-height: 44px;
    width: 44px;
    height: 44px;
    background: var(--gray-100);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--gray-700);
    transition: all var(--transition-base);
    flex-shrink: 0;
}

.logout-btn-sidebar:hover {
    background: var(--error);
    color: white;
    border-color: var(--error);
    transform: scale(1.05);
}

/* ===========================================
   Chat Main Area - Modern Card Design
   =========================================== */

.chat-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: var(--bg-secondary);
    position: relative;
}

.chat-header {
    padding: var(--space-xl) var(--space-2xl);
    background: white;
    border-bottom: 1px solid var(--gray-200);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-xs);
    height: 104px;
    box-sizing: border-box;
}

.chat-header h2 {
    font-size: var(--text-xl);
    font-weight: 600;
    color: var(--gray-900);
    letter-spacing: -0.3px;
    text-align: center;
}

.icon-btn {
    min-width: 44px;
    min-height: 44px;
    width: 44px;
    height: 44px;
    background: var(--gray-100);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-md);
    color: var(--gray-700);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-base);
}

.icon-btn:hover {
    background: var(--gray-200);
    transform: scale(1.05);
}

.btn-secondary {
    background: white;
    color: var(--gray-700);
    border: 1px solid var(--gray-300);
    min-height: 44px;
    padding: 10px var(--space-md);
    font-size: var(--text-sm);
}

.btn-secondary:hover {
    background: var(--gray-50);
    border-color: var(--gray-400);
}

/* Chat Messages - Modern Cards */
.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: var(--space-2xl);
    display: flex;
    flex-direction: column;
    gap: var(--space-xl);
}

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

.chat-messages::-webkit-scrollbar-track {
    background: transparent;
}

.chat-messages::-webkit-scrollbar-thumb {
    background: var(--gray-300);
    border-radius: 4px;
}

.message {
    display: flex;
    gap: var(--space-md);
    animation: messageSlideIn var(--transition-base);
}

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

.message-avatar {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: var(--text-sm);
    flex-shrink: 0;
    box-shadow: var(--shadow-sm);
}

.message.user .message-avatar {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.message.assistant .message-avatar {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    color: white;
}

.message-content {
    flex: 1;
    min-width: 0;
}

.message-header {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    margin-bottom: var(--space-xs);
}

.message-author {
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--gray-900);
}

.message-time {
    font-size: var(--text-xs);
    color: var(--gray-500);
}

.message-bubble {
    background: white;
    padding: var(--space-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--gray-200);
    line-height: 1.7;
}

.message.user .message-bubble {
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.05) 0%, rgba(118, 75, 162, 0.05) 100%);
    border-color: var(--primary-light);
}

.message-result-count {
    margin-top: var(--space-md);
    padding: var(--space-sm) var(--space-md);
    background: var(--gray-50);
    border-radius: var(--radius-sm);
    font-size: var(--text-sm);
    color: var(--gray-600);
}

/* Welcome Message */
.welcome-message {
    text-align: center;
    padding: var(--space-3xl) var(--space-xl);
    max-width: 600px;
    margin: auto;
}

.welcome-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto var(--space-xl);
    background: var(--bg-gradient);
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    box-shadow: var(--shadow-xl);
}

.welcome-message h3 {
    font-size: var(--text-2xl);
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: var(--space-md);
}

.welcome-message > p {
    font-size: var(--text-base);
    color: var(--gray-600);
    margin-bottom: var(--space-2xl);
}

.example-queries {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.example-title {
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--gray-700);
    margin-bottom: var(--space-sm);
}

.example-query {
    min-height: 44px;
    padding: 12px var(--space-lg);
    background: white;
    border: 2px solid var(--gray-200);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-base);
    font-size: var(--text-sm);
    color: var(--gray-700);
    text-align: left;
}

.example-query:hover {
    border-color: var(--primary);
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.05) 0%, rgba(118, 75, 162, 0.05) 100%);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* ===========================================
   Chat Input - Modern Floating Design
   =========================================== */

.chat-input-container {
    padding: var(--space-xl) var(--space-2xl);
    background: white;
    border-top: 1px solid var(--gray-200);
    box-shadow: 0 -4px 6px -1px rgba(0, 0, 0, 0.05);
    height: 136px;
    box-sizing: border-box;
    display: flex;
    align-items: center;
}

.chat-input-form {
    max-width: 900px;
    margin: 0 auto;
    width: 100%;
    flex: 1;
}

.chat-input-wrapper {
    background: white;
    border: 2px solid var(--gray-300);
    border-radius: var(--radius-xl);
    display: flex;
    align-items: flex-end;
    gap: var(--space-sm);
    padding: var(--space-md);
    transition: all var(--transition-base);
    box-shadow: var(--shadow-sm);
}

.chat-input-wrapper:focus-within {
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.1), var(--shadow-md);
}

.chat-input-wrapper textarea {
    flex: 1;
    min-height: 44px;
    border: none;
    outline: none;
    resize: none;
    font-family: var(--font-sans);
    font-size: var(--text-base);
    line-height: 1.6;
    max-height: 200px;
    padding: 10px 0;
    color: var(--gray-900);
}

.chat-input-wrapper textarea::placeholder {
    color: var(--gray-400);
}

.chat-input-actions {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.reasoning-select {
    padding: var(--space-sm) var(--space-md);
    border: 1px solid var(--gray-300);
    border-radius: var(--radius-md);
    font-size: var(--text-sm);
    color: var(--gray-700);
    background: var(--gray-50);
    cursor: pointer;
    transition: all var(--transition-base);
    font-family: var(--font-sans);
}

.reasoning-select:hover {
    background: var(--gray-100);
    border-color: var(--gray-400);
}


.send-btn {
    min-width: 44px;
    min-height: 44px;
    width: 44px;
    height: 44px;
    background: var(--bg-gradient);
    border: none;
    border-radius: var(--radius-md);
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-base);
    box-shadow: var(--shadow-sm);
}

.send-btn:hover:not(:disabled) {
    transform: scale(1.1);
    box-shadow: var(--shadow-md);
}

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

/* ===========================================
   Loading States
   =========================================== */

.loading-message {
    display: flex;
    gap: var(--space-md);
}

.message-loading {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-md) 0;
}

.thinking-text {
    font-size: var(--text-sm);
    color: var(--gray-600);
    font-weight: 500;
    letter-spacing: 0.5px;
}

.loading-dots {
    display: flex;
    gap: var(--space-xs);
    align-items: center;
}

.loading-dots span {
    width: 8px;
    height: 8px;
    background: var(--primary);
    border-radius: 50%;
    animation: bounce 1.4s infinite ease-in-out both;
}

.loading-dots span:nth-child(1) { animation-delay: -0.32s; }
.loading-dots span:nth-child(2) { animation-delay: -0.16s; }
.loading-dots span:nth-child(3) { animation-delay: 0s; }

@keyframes bounce {
    0%, 80%, 100% {
        transform: scale(0);
        opacity: 0.5;
    }
    40% {
        transform: scale(1);
        opacity: 1;
    }
}

/* Thinking animation with gradient shimmer */
.message-bubble .message-loading {
    background: linear-gradient(90deg,
        var(--gray-50) 0%,
        var(--gray-100) 50%,
        var(--gray-50) 100%);
    background-size: 200% 100%;
    animation: shimmer 2s ease-in-out infinite;
    padding: var(--space-lg);
    border-radius: var(--radius-md);
}

@keyframes shimmer {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

/* ===========================================
   Visualizations - Modern Data Display
   =========================================== */

.visualization-container {
    margin: var(--space-lg) 0;
    padding: var(--space-lg);
    background: white;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
}

.viz-toolbar {
    display: flex;
    gap: var(--space-xs);
    margin-bottom: var(--space-md);
    padding: var(--space-xs);
    background: var(--gray-50);
    border-radius: var(--radius-md);
    width: fit-content;
    border: 1px solid var(--gray-200);
}

.viz-toggle-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-sm);
    background: transparent;
    border: none;
    border-radius: var(--radius-sm);
    cursor: pointer;
    color: var(--gray-600);
    transition: all var(--transition-base);
}

.viz-toggle-btn:hover {
    background: white;
    color: var(--primary);
    box-shadow: var(--shadow-xs);
}

.viz-toggle-btn.active {
    background: var(--bg-gradient);
    color: white;
    box-shadow: var(--shadow-sm);
}

.viz-chart {
    background: white;
    border-radius: var(--radius-md);
    padding: var(--space-md);
}

/* Mobile chart note - hidden by default, shown on mobile */
.viz-chart-mobile-note {
    display: none;
}

/* Table Visualization - Modern Grid */
.viz-table-wrapper {
    border-radius: var(--radius-md);
    border: 1px solid var(--gray-200);
    background: white;
    overflow: hidden;
}

.viz-table-wrapper::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

.viz-table-wrapper::-webkit-scrollbar-track {
    background: var(--gray-100);
}

.viz-table-wrapper::-webkit-scrollbar-thumb {
    background: var(--gray-400);
    border-radius: 4px;
}

.viz-table {
    width: 100%;
    border-collapse: collapse;
    font-size: var(--text-sm);
}

.viz-table thead {
    position: sticky;
    top: 0;
    z-index: 10;
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.05) 0%, rgba(118, 75, 162, 0.05) 100%);
}

.viz-table th {
    padding: var(--space-md);
    text-align: left;
    font-weight: 600;
    color: var(--gray-900);
    border-bottom: 2px solid var(--gray-300);
    white-space: nowrap;
}

.viz-table td {
    padding: var(--space-md);
    border-bottom: 1px solid var(--gray-200);
    color: var(--gray-700);
}

.viz-table tr.even {
    background: var(--gray-50);
}

.viz-table tr:hover {
    background: rgba(99, 102, 241, 0.05);
}

.viz-table-note {
    padding: var(--space-sm) var(--space-md);
    background: var(--warning);
    color: white;
    font-size: var(--text-sm);
    text-align: center;
    font-weight: 500;
}

/* ===========================================
   Responsive Design
   =========================================== */

/* Mobile sidebar backdrop */
.sidebar-backdrop {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: var(--z-sticky);
    opacity: 0;
    transition: opacity var(--transition-base);
}

.sidebar-backdrop.show {
    display: block;
    opacity: 1;
}

@media (max-width: 768px) {
    .sidebar {
        position: fixed;
        left: -280px;
        top: 0;
        bottom: 0;
        transition: left var(--transition-base);
        z-index: var(--z-fixed);
    }

    .sidebar.open {
        left: 0;
        box-shadow: var(--shadow-2xl);
    }

    /* Hide desktop collapse button on mobile */
    .sidebar-collapse-btn {
        display: none;
    }

    /* Show mobile sidebar close button */
    .sidebar .mobile-sidebar-close {
        display: flex;
    }

    /* Ensure it only appears when sidebar is open */
    .sidebar:not(.open) .mobile-sidebar-close {
        opacity: 0;
        pointer-events: none;
    }

    /* Show delete buttons more prominently on mobile */
    .conversation-delete-btn {
        opacity: 0.5;
    }

    .conversation-item:hover .conversation-delete-btn {
        opacity: 1;
    }

    /* Mobile header optimization */
    .chat-header {
        padding: var(--space-md) var(--space-md); /* Reduced for narrow screens */
        height: auto;
        min-height: 60px;
    }

    .chat-header h2 {
        font-size: var(--text-base);
        overflow: hidden;
        text-overflow: ellipsis;
        white-space: nowrap;
    }

    .chat-messages {
        padding: var(--space-sm) var(--space-md); /* Reduced vertical padding */
        gap: var(--space-md); /* Reduce gap between messages */
    }

    .chat-input-container {
        padding: var(--space-md); /* Reduced from lg to md */
    }

    /* Mobile message optimization - stack vertically for max width */
    .message {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--space-sm); /* Increased spacing between avatar and chat */
        max-width: 100%; /* Constrain to viewport width */
        width: 100%; /* Full width of container */
    }

    .message.assistant {
        align-items: flex-start;
    }

    .message.user {
        align-items: flex-end;
    }

    .message-avatar {
        width: 28px;
        height: 28px;
        font-size: 11px;
    }

    .message-header {
        display: none; /* Hide author name on mobile - obvious from avatar */
    }

    .message-content {
        width: 100%;
        max-width: 100%;
        min-width: 0; /* Allow flex shrinking */
        overflow-wrap: break-word; /* Break long words */
        word-break: break-word; /* Break long unbreakable strings */
    }

    .message-bubble {
        padding: var(--space-sm) var(--space-md);
        font-size: var(--text-sm);
        max-width: 100%;
        width: 100%;
        box-sizing: border-box; /* Include padding in width */
        overflow-wrap: break-word; /* Break long words */
        word-break: break-word; /* Break URLs and long strings */
        overflow: hidden; /* Clip overflowing visualizations */
    }

    /* Handle code blocks and pre-formatted text */
    .message-bubble pre {
        overflow-x: auto; /* Horizontal scroll for code */
        max-width: 100%;
        white-space: pre-wrap; /* Wrap long lines */
        word-wrap: break-word; /* Break if needed */
        background: var(--gray-50);
        padding: var(--space-sm);
        border-radius: var(--radius-sm);
        font-size: 12px;
    }

    .message-bubble code {
        word-wrap: break-word;
        white-space: pre-wrap;
        max-width: 100%;
    }

    /* Handle tables */
    .message-bubble table {
        max-width: 100%;
        overflow-x: auto;
        display: block;
    }

    /* Handle images */
    .message-bubble img {
        max-width: 100%;
        height: auto;
    }

    .message-time {
        font-size: 10px;
    }

    /* Welcome message mobile optimization */
    .welcome-message {
        padding: var(--space-xl) var(--space-md);
    }

    .welcome-icon {
        width: 60px;
        height: 60px;
        margin-bottom: var(--space-md);
    }

    /* Visualization mobile optimization - hide charts, show tables only */
    .visualization-container {
        margin: var(--space-sm) 0 !important;
        padding: 0 !important;
        width: 100% !important;
        max-width: 100% !important;
        box-sizing: border-box !important;
        overflow: hidden !important;
    }

    /* Hide chart visualizations on mobile */
    .viz-chart {
        display: none !important;
    }

    /* Hide chart toggle button on mobile */
    .viz-toggle-btn[data-viz-type="chart"] {
        display: none !important;
    }

    /* Auto-show table view on mobile - full width with scroll */
    .viz-table-wrapper {
        display: block !important;
        margin: 0 !important;
        width: 100% !important;
        max-width: 100% !important;
        overflow-x: auto !important;
        -webkit-overflow-scrolling: touch; /* Smooth scrolling on iOS */
        border-radius: 0 !important;
        border: none !important;
        border-top: 1px solid var(--gray-200) !important;
        border-bottom: 1px solid var(--gray-200) !important;
        box-sizing: border-box !important;
    }

    .viz-table {
        width: 100%;
        font-size: 11px; /* Smaller font for mobile */
        margin: 0;
    }

    .viz-table th,
    .viz-table td {
        padding: var(--space-xs) var(--space-sm);
        white-space: nowrap; /* Prevent text wrapping in cells */
        font-size: 11px;
    }

    .viz-table th:first-child,
    .viz-table td:first-child {
        padding-left: var(--space-md); /* Add padding to first column */
    }

    .viz-table th:last-child,
    .viz-table td:last-child {
        padding-right: var(--space-md); /* Add padding to last column */
    }

    /* Show a message for mobile users */
    .viz-chart-mobile-note {
        display: block !important;
        padding: var(--space-sm);
        background: var(--gray-50);
        border: 1px solid var(--gray-200);
        border-radius: var(--radius-sm);
        font-size: var(--text-sm);
        color: var(--gray-600);
        text-align: center;
        margin-bottom: var(--space-sm);
    }

    /* Hide toolbar completely on mobile - tables only */
    .viz-toolbar {
        display: none !important;
    }

    .viz-toggle-btn {
        display: none !important;
    }

    /* Message result count mobile */
    .message-result-count {
        margin-top: var(--space-sm);
        padding: var(--space-xs) var(--space-sm);
        font-size: 11px;
    }
}

/* Extra small devices (iPhone SE and similar - 320px to 375px) */
@media (max-width: 375px) {
    .chat-messages {
        padding: var(--space-sm);
        gap: var(--space-sm);
    }

    .message-avatar {
        width: 24px;
        height: 24px;
        font-size: 10px;
    }

    .message {
        flex-direction: column;
        gap: 6px;
    }

    .message-bubble {
        padding: var(--space-xs) var(--space-sm);
        font-size: 13px;
        line-height: 1.5;
        max-width: 100%;
    }

    .chat-header h2 {
        font-size: var(--text-base);
    }

    .welcome-message h3 {
        font-size: var(--text-xl);
    }

    .welcome-icon {
        width: 50px;
        height: 50px;
    }

    .mobile-menu-toggle {
        width: 44px;
        height: 44px;
        min-width: 44px;
        min-height: 44px;
    }
}

/* Narrow mobile devices (iPhone 12 Pro, etc) */
@media (max-width: 390px) {
    .chat-header {
        padding: var(--space-sm) var(--space-sm); /* Further reduced for iPhone 12 Pro */
    }

    .chat-messages {
        padding: var(--space-xs) var(--space-sm);
    }

    .chat-input-container {
        padding: var(--space-sm);
    }

    .chat-input-wrapper {
        padding: var(--space-sm);
    }

    .welcome-message {
        padding: var(--space-md) var(--space-sm);
    }

    /* Extra tight constraints for visualizations on narrow screens */
    .visualization-container {
        padding: var(--space-xs);
        margin: var(--space-sm) 0;
    }

    .viz-chart {
        padding: 0;
    }
}

/* ===========================================
   Utility Classes
   =========================================== */

.hidden {
    display: none !important;
}

/* Focus Styles - Accessibility */
:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

/* Smooth Scrolling */
html {
    scroll-behavior: smooth;
}

/* Selection */
::selection {
    background: var(--primary-light);
    color: white;
}

/* ===========================================
   Confirmation Modal - Modern Design
   =========================================== */

.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--bg-overlay);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1400;
    padding: var(--space-lg);
    opacity: 1;
    transition: opacity var(--transition-base), visibility var(--transition-base);
}

.modal-overlay.hidden {
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
}

.modal-container {
    background: white;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-2xl);
    max-width: 480px;
    width: 100%;
    overflow: hidden;
    animation: modalSlideIn var(--transition-slow);
    border: 1px solid var(--gray-200);
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: scale(0.9) translateY(-20px);
    }
    to {
        opacity: 1;
        transform: scale(1) translateY(0);
    }
}

.modal-header {
    padding: var(--space-xl);
    border-bottom: 1px solid var(--gray-200);
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.05) 0%, rgba(118, 75, 162, 0.05) 100%);
}

.modal-title {
    font-size: var(--text-xl);
    font-weight: 600;
    color: var(--gray-900);
    margin: 0;
}

.modal-body {
    padding: var(--space-xl);
}

.modal-message {
    font-size: var(--text-base);
    color: var(--gray-700);
    line-height: 1.6;
    margin: 0;
}

.modal-footer {
    padding: var(--space-lg) var(--space-xl);
    border-top: 1px solid var(--gray-200);
    background: var(--gray-50);
    display: flex;
    gap: var(--space-md);
    justify-content: flex-end;
}

.modal-footer .btn {
    min-width: 100px;
}

.btn-danger {
    background: var(--error);
    color: white;
    box-shadow: var(--shadow-sm);
}

.btn-danger:hover {
    background: #dc2626;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

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

/* ===========================================
   Toast Notifications
   =========================================== */

.error-toast {
    position: fixed;
    bottom: var(--space-xl);
    right: var(--space-xl);
    background: var(--error);
    color: white;
    padding: var(--space-md) var(--space-lg);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-xl);
    font-size: var(--text-sm);
    font-weight: 500;
    z-index: var(--z-tooltip);
    opacity: 1;
    transition: opacity var(--transition-base);
    max-width: 400px;
    animation: toastSlideIn var(--transition-base);
}

@keyframes toastSlideIn {
    from {
        opacity: 0;
        transform: translateX(100%);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}