:root {
        --primary-color: #10b981;
        --primary-dark: #059669;
        --secondary-color: #374151;
        --background-light: #f9fafb;
        --background-dark: #1f2937;
        --background-color: #ffffff;
        --text-primary: #111827;
        --text-secondary: #6b7280;
        --text-muted: #9ca3af;
        --border-color: #e5e7eb;
        --border-color-dark: #374151;
        --chat-bg: #ffffff;
        --card-bg: #ffffff;
        --input-bg: #ffffff;
        --sidebar-bg: #f8fafc;
        --success-color: #059669;
        --warning-color: #d97706;
        --danger-color: #dc2626;
        --info-color: #0ea5e9;
        --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
        --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
        --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
        --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
        --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
        --border-radius: 0.5rem;
        --border-radius-sm: 0.25rem;
        --border-radius-lg: 0.75rem;
        --transition: all 0.2s ease;
    }

    [data-theme="dark"] {
        --primary-color: #34d399;
        --primary-dark: #10b981;
        --secondary-color: #9ca3af;
        --background-light: #111827;
        --background-dark: #0f172a;
        --background-color: #0f172a;
        --text-primary: #f9fafb;
        --text-secondary: #9ca3af;
        --text-muted: #6b7280;
        --border-color: #374151;
        --border-color-dark: #4b5563;
        --chat-bg: #1f2937;
        --card-bg: #1f2937;
        --input-bg: #111827;
        --sidebar-bg: #111827;
        --success-color: #34d399;
        --warning-color: #fbbf24;
        --danger-color: #f87171;
        --info-color: #38bdf8;
        --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.2);
        --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.3), 0 1px 2px 0 rgba(0, 0, 0, 0.2);
        --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -1px rgba(0, 0, 0, 0.2);
        --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.3), 0 4px 6px -2px rgba(0, 0, 0, 0.2);
        --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.3), 0 10px 10px -5px rgba(0, 0, 0, 0.15);
        /* -webkit-text-fill-color: #EDEAE0; */
    }
    
    * {
        box-sizing: border-box;
    }
    
    body {
        font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
        margin: 0;
        padding: 0;
        background-color: var(--background-color);
        color: var(--text-primary);
        line-height: 1.6;
        transition: background-color 0.3s ease, color 0.3s ease;
    }

    .dark-mode-toggle {
        background: none;
        border: none;
        color: rgba(255,255,255,0.9);
        font-size: 1.1rem;
        cursor: pointer;
        padding: 0.5rem;
        border-radius: 0.5rem;
        transition: all 0.2s ease;
    }

    .dark-mode-toggle:hover {
        background-color: rgba(255,255,255,0.1);
        color: white;
    }
    
    .navbar {
        background: rgba(255, 255, 255, 0.1) !important;
        backdrop-filter: blur(20px) !important;
        -webkit-backdrop-filter: blur(20px) !important;
        border-bottom: 1px solid rgba(255, 255, 255, 0.2) !important;
        box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1) !important;
        padding: 1rem 0;
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        z-index: 1030;
        transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    }

    [data-theme="dark"] .navbar {
        background: rgba(15, 23, 42, 0.8) !important;
        border-bottom: 1px solid rgba(255, 255, 255, 0.1) !important;
    }

    .navbar-brand {
        font-weight: 800;
        font-size: 1.75rem;
        color: var(--text-primary) !important;
        text-decoration: none;
        display: flex;
        align-items: center;
        position: relative;
        overflow: hidden;
    }

    .navbar-brand::before {
        content: '';
        position: absolute;
        top: 0;
        left: -100%;
        width: 100%;
        height: 100%;
        background: linear-gradient(90deg, transparent, rgba(16, 185, 129, 0.2), transparent);
        transition: left 0.5s;
    }

    .navbar-brand:hover::before {
        left: 100%;
    }

    .navbar-brand i {
        color: var(--primary-color);
        font-size: 1.5rem;
        margin-right: 0.5rem;
        transition: all 0.3s ease;
    }

    .navbar-brand:hover i {
        transform: rotate(10deg) scale(1.1);
    }

    .navbar-nav .nav-link {
        color: var(--text-primary) !important;
        font-weight: 600;
        margin: 0 0.25rem;
        padding: 0.75rem 1.25rem !important;
        border-radius: 1rem;
        transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        position: relative;
        overflow: hidden;
    }

    .navbar-nav .nav-link::before {
        content: '';
        position: absolute;
        top: 0;
        left: -100%;
        width: 100%;
        height: 100%;
        background: linear-gradient(90deg, transparent, rgba(16, 185, 129, 0.1), transparent);
        transition: left 0.5s;
    }

    .navbar-nav .nav-link:hover::before {
        left: 100%;
    }

    .navbar-nav .nav-link:hover {
        background: rgba(16, 185, 129, 0.1) !important;
        color: var(--primary-color) !important;
        transform: translateY(-2px);
        box-shadow: 0 4px 12px rgba(16, 185, 129, 0.2);
    }

    .navbar-nav .nav-link i {
        margin-right: 0.375rem;
        transition: all 0.3s ease;
    }

    .navbar-nav .nav-link:hover i {
        transform: scale(1.1);
    }

    .dark-mode-toggle {
        background: rgba(16, 185, 129, 0.1) !important;
        border: 2px solid rgba(16, 185, 129, 0.3) !important;
        color: var(--primary-color) !important;
        font-size: 1.2rem;
        cursor: pointer;
        padding: 0.625rem;
        border-radius: 0.75rem;
        transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        position: relative;
        overflow: hidden;
    }

    .dark-mode-toggle::before {
        content: '';
        position: absolute;
        top: 0;
        left: -100%;
        width: 100%;
        height: 100%;
        background: linear-gradient(90deg, transparent, rgba(16, 185, 129, 0.2), transparent);
        transition: left 0.5s;
    }

    .dark-mode-toggle:hover::before {
        left: 100%;
    }

    .dark-mode-toggle:hover {
        background: rgba(16, 185, 129, 0.2) !important;
        border-color: var(--primary-color) !important;
        transform: translateY(-2px) scale(1.05);
        box-shadow: 0 6px 20px rgba(16, 185, 129, 0.3);
    }

    .user-avatar img {
        border: 2px solid rgba(16, 185, 129, 0.3);
        transition: all 0.3s ease;
    }

    .user-avatar img:hover {
        border-color: var(--primary-color);
        transform: scale(1.05);
    }

    .avatar-placeholder {
        width: 32px;
        height: 32px;
        border-radius: 50%;
        background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
        color: white;
        display: flex;
        align-items: center;
        justify-content: center;
        font-weight: 700;
        font-size: 0.875rem;
        border: 2px solid rgba(255, 255, 255, 0.2);
        transition: all 0.3s ease;
    }

    .avatar-placeholder:hover {
        transform: scale(1.05);
        box-shadow: 0 4px 12px rgba(16, 185, 129, 0.3);
    }

    .dropdown-menu {
        background: var(--card-bg);
        border: 1px solid var(--border-color);
        border-radius: 1rem;
        box-shadow: 0 10px 40px rgba(0, 0, 0, 0.15);
        backdrop-filter: blur(10px);
        -webkit-backdrop-filter: blur(10px);
        padding: 0.5rem;
        margin-top: 0.5rem;
    }

    .dropdown-item {
        color: var(--text-primary);
        font-weight: 500;
        padding: 0.75rem 1rem;
        border-radius: 0.5rem;
        transition: all 0.2s ease;
    }

    .dropdown-item:hover {
        background: rgba(16, 185, 129, 0.1);
        color: var(--primary-color);
        transform: translateX(4px);
    }

    .dropdown-item i {
        width: 1rem;
        margin-right: 0.5rem;
    }

    .navbar-toggler {
        border: 2px solid rgba(16, 185, 129, 0.3);
        border-radius: 0.5rem;
        padding: 0.375rem 0.5rem;
        transition: all 0.3s ease;
    }

    .navbar-toggler:hover {
        border-color: var(--primary-color);
        background: rgba(16, 185, 129, 0.1);
    }

    .navbar-toggler-icon {
        background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3e%3cpath stroke='rgba(16, 185, 129, 0.8)' stroke-linecap='round' stroke-miterlimit='10' stroke-width='2' d='m4 7h22M4 15h22M4 23h22'/%3e%3c/svg%3e");
    }

    @media (max-width: 991.98px) {
        .navbar-collapse {
            background: var(--card-bg);
            border-radius: 1rem;
            margin-top: 1rem;
            padding: 1rem;
            box-shadow: 0 10px 40px rgba(0, 0, 0, 0.15);
            backdrop-filter: blur(10px);
            -webkit-backdrop-filter: blur(10px);
            border: 1px solid var(--border-color);
        }

        .navbar-nav .nav-link {
            margin: 0.25rem 0;
            padding: 0.75rem 1rem !important;
        }

        .navbar-brand span {
            display: inline !important;
        }
    }
    
    .main-content {
        margin-top: 80px;
        min-height: calc(100vh - 80px);
    }
    
    .btn-primary {
        background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
        border: none;
        border-radius: 0.5rem;
        font-weight: 500;
        padding: 0.75rem 1.5rem;
        transition: all 0.2s ease;
    }
    
    .btn-primary:hover {
        transform: translateY(-1px);
        box-shadow: 0 4px 8px rgba(16, 185, 129, 0.3);
    }
    
    .card {
        border: none;
        border-radius: 1rem;
        box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
        transition: all 0.3s ease;
    }
    
    .card:hover {
        transform: translateY(-2px);
        box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
    }
    
    .form-control {
        border: 2px solid var(--border-color);
        border-radius: 0.5rem;
        padding: 0.75rem;
        transition: all 0.2s ease;
    }
    
    .form-control:focus {
        border-color: var(--primary-color);
        box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.1);
    }
    
    .chat-container {
        display: flex;
        height: calc(100vh - 80px);
        background: var(--chat-bg);
    }
    
    .sidebar {
        width: 260px;
        background: var(--sidebar-bg);
        border-right: 1px solid var(--border-color);
        padding: 1rem;
        overflow-y: auto;
    }
    
    .chat-main {
        flex: 1;
        display: flex;
        flex-direction: column;
    }
    
    .chat-messages {
        flex: 1;
        overflow-y: auto;
        padding: 1rem;
    }
    
    .message {
        margin-bottom: 1.5rem;
        display: flex;
        align-items: flex-start;
        gap: 0.75rem;
    }
    
    .message.user {
        flex-direction: row-reverse;
    }
    
    .message-avatar {
        width: 32px;
        height: 32px;
        border-radius: 50%;
        display: flex;
        align-items: center;
        justify-content: center;
        font-weight: 600;
        font-size: 0.875rem;
    }
    
    .message.user .message-avatar {
        background: var(--primary-color);
        color: white;
    }
    
    .message.assistant .message-avatar {
        background: var(--secondary-color);
        color: white;
    }
    
    .message-content {
        background: var(--background-light);
        border-radius: 1rem;
        padding: 1rem;
        max-width: 70%;
        box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    }
    
    .message.user .message-content {
        background: var(--primary-color);
        color: white;
    }
    
    .chat-input-container {
        padding: 1rem;
        border-top: 1px solid var(--border-color);
        background: white;
    }
    
    .alert {
        border-radius: 0.75rem;
        border: none;
        padding: 1rem;
    }
    
    .alert-success {
        background-color: #d1fae5;
        color: #065f46;
    }
    
    .alert-danger {
        background-color: #fee2e2;
        color: #991b1b;
    }
    
    .dashboard-stats {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
        gap: 1.5rem;
        margin-bottom: 2rem;
    }
    
    .stat-card {
        background: white;
        border-radius: 1rem;
        padding: 1.5rem;
        text-align: center;
        border: 1px solid var(--border-color);
    }
    
    .stat-number {
        font-size: 2rem;
        font-weight: 700;
        color: var(--primary-color);
    }
    
    .stat-label {
        color: var(--text-secondary);
        font-weight: 500;
    }
    
    @media (max-width: 768px) {
        .sidebar {
            width: 100%;
            height: auto;
            position: relative;
        }
        
        .chat-container {
            flex-direction: column;
            height: auto;
        }
        
        .main-content {
            margin-top: 70px;
        }
        
        .navbar-brand {
            font-size: 1.25rem;
        }
    }
    
    /* Bootstrap Dark Mode Overrides */
    [data-theme="dark"] .card {
        background-color: var(--card-bg);
        border-color: var(--border-color);
        color: var(--text-primary);
    }
    
    [data-theme="dark"] .form-control,
    [data-theme="dark"] .form-select {
        background-color: var(--input-bg);
        border-color: var(--border-color);
        color: var(--text-primary);
    }
    
    [data-theme="dark"] .form-control:focus,
    [data-theme="dark"] .form-select:focus {
        background-color: var(--input-bg);
        border-color: var(--primary-color);
        color: var(--text-primary);
        box-shadow: 0 0 0 0.2rem rgba(52, 211, 153, 0.25);
    }
    
    [data-theme="dark"] .dropdown-menu {
        background-color: var(--card-bg);
        border-color: var(--border-color);
    }
    
    [data-theme="dark"] .dropdown-item {
        color: var(--text-primary);
    }
    
    [data-theme="dark"] .dropdown-item:hover,
    [data-theme="dark"] .dropdown-item:focus {
        background-color: var(--background-light);
    }
    
    [data-theme="dark"] .modal-content {
        background-color: var(--card-bg);
        border-color: var(--border-color);
    }
    
    [data-theme="dark"] .modal-header {
        border-bottom-color: var(--border-color);
    }
    
    [data-theme="dark"] .modal-footer {
        border-top-color: var(--border-color);
    }
    
    [data-theme="dark"] .breadcrumb-item + .breadcrumb-item::before {
        color: var(--text-secondary);
    }
    
    [data-theme="dark"] .nav-pills .nav-link {
        color: var(--text-secondary);
    }
    
    [data-theme="dark"] .nav-pills .nav-link.active {
        background-color: var(--primary-color);
    }
    
    [data-theme="dark"] .table {
        color: var(--text-primary);
    }
    
    [data-theme="dark"] .table th,
    [data-theme="dark"] .table td {
        border-color: var(--border-color);
    }
    
    [data-theme="dark"] .alert-primary {
        background-color: rgba(52, 211, 153, 0.1);
        border-color: rgba(52, 211, 153, 0.2);
        color: var(--primary-color);
    }
    
    [data-theme="dark"] .alert-success {
        background-color: rgba(52, 211, 153, 0.1);
        border-color: rgba(52, 211, 153, 0.2);
        color: var(--success-color);
    }
    
    [data-theme="dark"] .alert-warning {
        background-color: rgba(251, 191, 36, 0.1);
        border-color: rgba(251, 191, 36, 0.2);
        color: var(--warning-color);
    }
    
    [data-theme="dark"] .alert-danger {
        background-color: rgba(248, 113, 113, 0.1);
        border-color: rgba(248, 113, 113, 0.2);
        color: var(--danger-color);
    }
    
    [data-theme="dark"] .text-muted {
        color: var(--text-secondary) !important;
    }
    [dark-theme="dark"] .text-white{
        color: #f9fafb;
    }

    [data-theme="dark"] .subject-hero {
        background: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #334155 100%);
    }   

main {
    flex-grow: 1;
    padding: 20px;
    background-color: var(--background-color);
    color: var(--text-color);
    /* The line below might exist and should be removed or commented out */
    height: calc(100vh - 60px); /* REMOVE THIS LINE */
}