/* Main styles for Thuy Van On Thi web app */

:root {
    --primary-color: #3498db;
    --secondary-color: #2c3e50;
    --success-color: #27ae60;
    --warning-color: #f39c12;
    --danger-color: #e74c3c;
    --light-color: #ecf0f1;
    --dark-color: #34495e;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    min-height: 100vh;
    padding-bottom: 60px;
}

.navbar {
    background: linear-gradient(135deg, var(--primary-color) 0%, #2980b9 100%);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.navbar-brand {
    font-weight: bold;
    font-size: 1.5rem;
}

.card {
    border: none;
    border-radius: 15px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    transition: transform 0.3s ease;
    margin-bottom: 20px;
}

.card:hover {
    transform: translateY(-5px);
}

.card-header {
    border-radius: 15px 15px 0 0 !important;
    font-weight: 600;
}

.btn {
    border-radius: 8px;
    padding: 10px 20px;
    font-weight: 500;
    transition: all 0.3s ease;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color) 0%, #2980b9 100%);
    border: none;
}

.btn-success {
    background: linear-gradient(135deg, var(--success-color) 0%, #219653 100%);
    border: none;
}

.btn-warning {
    background: linear-gradient(135deg, var(--warning-color) 0%, #d68910 100%);
    border: none;
}

.btn-danger {
    background: linear-gradient(135deg, var(--danger-color) 0%, #c0392b 100%);
    border: none;
}

.alert {
    border-radius: 10px;
    border: none;
}

/* Question styling */
.question-card {
    background: white;
    border-radius: 10px;
    padding: 25px;
    margin-bottom: 25px;
    box-shadow: 0 3px 10px rgba(0,0,0,0.08);
    border-left: 5px solid var(--primary-color);
}

.option-item {
    padding: 15px;
    margin: 10px 0;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s;
    border: 2px solid #e0e0e0;
    background: white;
}

.option-item:hover {
    background-color: #f8f9fa;
    border-color: var(--primary-color);
}

.option-item.selected {
    background-color: #e3f2fd;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(52, 152, 219, 0.2);
}

/* Timer styling */
#timer {
    font-family: 'Courier New', monospace;
    font-weight: bold;
    padding: 10px 15px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 8px;
}

/* Progress bar */
.progress {
    height: 10px;
    border-radius: 5px;
}

.progress-bar {
    background: linear-gradient(90deg, var(--success-color) 0%, var(--primary-color) 100%);
    border-radius: 5px;
}

/* Statistics cards */
.stats-item {
    padding: 15px;
    border-radius: 10px;
    background: #f8f9fa;
    margin-bottom: 15px;
}

/* Footer */
footer {
    margin-top: 50px;
    background: var(--secondary-color);
    color: white;
}

footer a {
    color: #ecf0f1;
    text-decoration: none;
}

footer a:hover {
    color: var(--primary-color);
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .card-body {
        padding: 15px;
    }
    
    .question-card {
        padding: 15px;
    }
    
    .option-item {
        padding: 10px;
    }
    
    h1, h2, h3 {
        font-size: 1.5rem;
    }
}

/* Custom scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #f1f1f1;
}

::-webkit-scrollbar-thumb {
    background: var(--primary-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #2980b9;
}

/* Animation for page transitions */
.fade-in {
    animation: fadeIn 0.5s ease-in;
}

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

/* Loading spinner */
.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid #f3f3f3;
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Badge custom */
.badge {
    padding: 8px 12px;
    border-radius: 20px;
    font-weight: 500;
}

/* Table styling */
.table-hover tbody tr:hover {
    background-color: rgba(52, 152, 219, 0.1);
}

.table thead th {
    border-bottom: 2px solid var(--primary-color);
    background-color: #f8f9fa;
}

/* Form styling */
.form-control {
    border-radius: 8px;
    padding: 12px;
    border: 2px solid #e0e0e0;
    transition: all 0.3s;
}

.form-control:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
}

/* Login/Register forms */
.auth-form {
    max-width: 400px;
    margin: 0 auto;
    padding: 30px;
    background: white;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
}