:root {
    /* Modern Color Palette */
    --primary: #2c3e50;
    --primary-dark: #1a252f;
    --primary-light: #34495e;
    --secondary: #3498db;
    --success: #27ae60;
    --warning: #f39c12;
    --danger: #e74c3c;
    --info: #2980b9;
    
    /* Light Theme */
    --bg-light: #f8f9fa;
    --card-light: #ffffff;
    --text-light: #2c3e50;
    --border-light: #dee2e6;
    --muted-light: #6c757d;
    
    /* Dark Theme */
    --bg-dark: #121212;
    --card-dark: #1e1e1e;
    --text-dark: #e9ecef;
    --border-dark: #343a40;
    --muted-dark: #adb5bd;
    
    /* Active Theme */
    --bg: var(--bg-light);
    --card: var(--card-light);
    --text: var(--text-light);
    --border: var(--border-light);
    --muted: var(--muted-light);
    
    /* Design Tokens */
    --radius-sm: 0.375rem;
    --radius: 0.75rem;
    --radius-lg: 1rem;
    --shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
    --shadow-md: 0 0.5rem 1rem rgba(0, 0, 0, 0.15);
    --shadow-lg: 0 1rem 3rem rgba(0, 0, 0, 0.175);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-bs-theme="dark"] {
    --bg: var(--bg-dark);
    --card: var(--card-dark);
    --text: var(--text-dark);
    --border: var(--border-dark);
    --muted: var(--muted-dark);
}

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

body {
    background-color: var(--bg);
    color: var(--text);
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    line-height: 1.6;
    min-height: 100vh;
    transition: var(--transition);
}

/* Enhanced Navigation */
.navbar {
    backdrop-filter: blur(10px);
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%) !important;
    border-bottom: 3px solid var(--secondary);
}

.navbar-brand {
    font-size: 1.25rem;
    font-weight: 700;
}

.nav-link {
    border-radius: var(--radius-sm);
    margin: 0.125rem;
    transition: var(--transition);
    font-weight: 500;
}

.nav-link:hover, .nav-link:focus {
    background: rgba(255, 255, 255, 0.1);
    transform: translateY(-1px);
}

/* Cards - Modern Design */
.card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    transition: var(--transition);
    backdrop-filter: blur(10px);
}

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

.card-header {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
    color: white;
    border-bottom: none;
    font-weight: 600;
    padding: 1.25rem 1.5rem;
}

/* Enhanced Tables */
.table {
    --bs-table-bg: transparent;
    --bs-table-color: var(--text);
    margin-bottom: 0;
}

.table th {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
    color: white;
    font-weight: 600;
    border: none;
    padding: 1rem 1.25rem;
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.table td {
    padding: 1rem 1.25rem;
    border-color: var(--border);
    vertical-align: middle;
    transition: var(--transition);
}

.table-hover tbody tr:hover td {
    background-color: rgba(var(--primary-dark), 0.05);
}

[data-bs-theme="dark"] .table-hover tbody tr:hover td {
    background-color: rgba(255, 255, 255, 0.05);
}

/* Buttons - Modern Style */
.btn {
    border-radius: var(--radius);
    font-weight: 600;
    padding: 0.75rem 1.5rem;
    transition: var(--transition);
    border: none;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
    transition: left 0.5s;
}

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

.btn-primary {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
}

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

/* Stats Grid - Modern Layout */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: linear-gradient(135deg, var(--card) 0%, rgba(var(--primary), 0.05) 100%);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 2rem;
    text-align: center;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--secondary), var(--success));
}

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--secondary), var(--success));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.5rem;
}

.stat-label {
    color: var(--muted);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-size: 0.875rem;
}

/* Forms - Modern Design */
.form-control, .form-select {
    background: var(--card);
    border: 2px solid var(--border);
    color: var(--text);
    border-radius: var(--radius);
    padding: 0.75rem 1rem;
    transition: var(--transition);
    font-size: 0.95rem;
}

.form-control:focus, .form-select:focus {
    border-color: var(--secondary);
    box-shadow: 0 0 0 0.2rem rgba(52, 152, 219, 0.25);
    background: var(--card);
    transform: translateY(-1px);
}

.form-label {
    color: var(--text);
    font-weight: 600;
    margin-bottom: 0.75rem;
    font-size: 0.95rem;
}

/* Badges - Modern Style */
.badge {
    border-radius: 50rem;
    padding: 0.5rem 1rem;
    font-weight: 600;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Loading Animation */
.loading-spinner {
    display: inline-block;
    width: 2rem;
    height: 2rem;
    border: 3px solid rgba(255,255,255,.3);
    border-radius: 50%;
    border-top-color: #fff;
    animation: spin 1s ease-in-out infinite;
}

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

/* Mobile First Responsive Design */
@media (max-width: 768px) {
    .container-fluid {
        padding: 0 1rem;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .stat-card {
        padding: 1.5rem;
    }
    
    .table-responsive {
        border-radius: var(--radius);
        border: 1px solid var(--border);
    }
    
    .btn {
        width: 100%;
        margin-bottom: 0.5rem;
    }
    
    .btn-group .btn {
        width: auto;
    }
    
    .navbar-nav {
        padding: 1rem 0;
    }
    
    .nav-link {
        margin: 0.25rem 0;
        padding: 0.75rem 1rem !important;
    }
}

@media (max-width: 576px) {
    body {
        font-size: 0.9rem;
    }
    
    .card {
        margin: 0 -0.5rem;
        border-radius: 0;
        border-left: none;
        border-right: none;
    }
    
    .table th, .table td {
        padding: 0.75rem 0.5rem;
        font-size: 0.85rem;
    }
    
    .stat-number {
        font-size: 2rem;
    }
}

/* Utility Classes */
.text-gradient {
    background: linear-gradient(135deg, var(--secondary), var(--success));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.shadow-custom {
    box-shadow: 0 0.5rem 1.5rem rgba(0, 0, 0, 0.1);
}

.border-gradient {
    border: 2px solid;
    border-image: linear-gradient(135deg, var(--secondary), var(--success)) 1;
}

/* Animation Classes */
.fade-in {
    animation: fadeIn 0.6s ease-out;
}

.slide-up {
    animation: slideUp 0.6s ease-out;
}

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

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(50px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Print Styles */
@media print {
    .navbar, .btn, .alert {
        display: none !important;
    }
    
    .card {
        border: 1px solid #000 !important;
        box-shadow: none !important;
    }
}