:root {
    --primary-color: #4f46e5;
    --secondary-color: #818cf8;
    --bg-color: #f3f4f6;
    --card-bg: #ffffff;
    --text-color: #1f2937;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
}

body {
    background-color: var(--bg-color);
    font-family: 'Inter', sans-serif;
    color: var(--text-color);
}

.navbar {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.navbar-brand {
    font-weight: 700;
    color: white !important;
}

.card {
    border: none;
    border-radius: 1rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
    transition: transform 0.2s ease-in-out;
    background-color: var(--card-bg);
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

.grade-badge {
    font-size: 1.5rem;
    font-weight: 800;
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    color: white;
}

.bg-success-gradient { background: linear-gradient(135deg, #10b981, #34d399); }
.bg-info-gradient { background: linear-gradient(135deg, #3b82f6, #60a5fa); }
.bg-warning-gradient { background: linear-gradient(135deg, #f59e0b, #fbbf24); }
.bg-danger-gradient { background: linear-gradient(135deg, #ef4444, #f87171); }

.btn-primary {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
}

.btn-primary:hover {
    background-color: #4338ca;
    border-color: #4338ca;
}

.stat-card {
    background: white;
    border-radius: 1rem;
    padding: 1.5rem;
    text-align: center;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
}

.stat-value {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--primary-color);
}

.stat-label {
    color: #6b7280;
    font-size: 0.875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.modal-content {
    border-radius: 1rem;
    border: none;
}

.modal-header {
    background-color: #f9fafb;
    border-bottom: 1px solid #e5e7eb;
    border-radius: 1rem 1rem 0 0;
}

.form-control {
    border-radius: 0.5rem;
    padding: 0.75rem 1rem;
    border: 1px solid #d1d5db;
}

.form-control:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}