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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f5f5;
}

/* Login Page */
.login-page {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.login-container {
    width: 100%;
    max-width: 440px;
    padding: 20px;
}

.login-card {
    background: white;
    border-radius: 10px;
    padding: 40px;
    box-shadow: 0 10px 40px rgba(0,0,0,0.1);
}

.login-header {
    text-align: center;
    margin-bottom: 30px;
}

.login-header h1 {
    font-size: 28px;
    color: #333;
    margin-bottom: 10px;
}

.login-header p {
    color: #666;
    font-size: 14px;
}

/* Form Styles */
.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: 500;
    color: #555;
}

.form-group input {
    width: 100%;
    padding: 12px;
    border: 1px solid #ddd;
    border-radius: 5px;
    font-size: 16px;
    transition: border-color 0.3s;
}

.form-group input:focus {
    outline: none;
    border-color: #667eea;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border: none;
    border-radius: 5px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-primary {
    background: #667eea;
    color: white;
}

.btn-primary:hover {
    background: #5a67d8;
}

.btn-block {
    width: 100%;
    display: block;
}

.btn:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

/* Alerts */
.alert {
    padding: 12px;
    border-radius: 5px;
    margin-bottom: 20px;
    font-size: 14px;
}

.alert-success {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.alert-error {
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.alert-warning {
    background: #fff3cd;
    color: #856404;
    border: 1px solid #ffeaa7;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
}

.modal-content {
    background-color: white;
    margin: 5% auto;
    padding: 30px;
    border-radius: 10px;
    width: 90%;
    max-width: 500px;
    position: relative;
}

.close {
    position: absolute;
    right: 20px;
    top: 20px;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
    color: #aaa;
}

.close:hover {
    color: #333;
}

/* Dashboard Layout */
.dashboard {
    display: flex;
    min-height: 100vh;
}

.sidebar {
    width: 250px;
    background: #2d3748;
    color: white;
    padding: 20px;
    position: fixed;
    height: 100vh;
    left: 0;
    top: 0;
}

.sidebar-header {
    padding-bottom: 20px;
    border-bottom: 1px solid #4a5568;
    margin-bottom: 20px;
}

.sidebar-header h2 {
    font-size: 20px;
}

.sidebar-nav {
    list-style: none;
}

.sidebar-nav li {
    margin-bottom: 5px;
}

.sidebar-nav a {
    display: block;
    padding: 10px 15px;
    color: #cbd5e0;
    text-decoration: none;
    border-radius: 5px;
    transition: background 0.3s;
}

.sidebar-nav a:hover,
.sidebar-nav a.active {
    background: #4a5568;
    color: white;
}

.main-content {
    margin-left: 250px;
    flex: 1;
    padding: 20px;
}

.top-bar {
    background: white;
    padding: 15px 20px;
    border-radius: 10px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    margin-bottom: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* Cards */
.card {
    background: white;
    border-radius: 10px;
    padding: 20px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    margin-bottom: 20px;
}

.card-header {
    border-bottom: 1px solid #e2e8f0;
    padding-bottom: 15px;
    margin-bottom: 15px;
}

.card-header h3 {
    font-size: 18px;
    color: #2d3748;
}

/* Tables */
.table {
    width: 100%;
    border-collapse: collapse;
}

.table th,
.table td {
    padding: 12px;
    text-align: left;
    border-bottom: 1px solid #e2e8f0;
}

.table th {
    background: #f7fafc;
    font-weight: 600;
    color: #4a5568;
}

.table tr:hover {
    background: #f7fafc;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 20px;
}

.stat-card {
    background: white;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.stat-card h3 {
    font-size: 14px;
    color: #718096;
    margin-bottom: 10px;
}

.stat-card .stat-value {
    font-size: 32px;
    font-weight: bold;
    color: #2d3748;
}

/* Exam Interface */
.exam-container {
    background: white;
    border-radius: 10px;
    padding: 30px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.exam-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 1px solid #e2e8f0;
}

.timer {
    font-size: 24px;
    font-weight: bold;
    color: #667eea;
}

.timer.warning {
    color: #e53e3e;
    animation: pulse 1s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.question-card {
    margin-bottom: 30px;
}

.question-card h3 {
    margin-bottom: 20px;
    color: #4a5568;
}

.question-text {
    font-size: 18px;
    line-height: 1.8;
    margin-bottom: 30px;
    color: #2d3748;
}

.options {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.option {
    display: block;
    padding: 15px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s;
}

.option:hover {
    border-color: #667eea;
    background: #f7fafc;
}

.option.selected {
    border-color: #667eea;
    background: #ebf4ff;
}

.option input[type="radio"] {
    margin-right: 10px;
}

.exam-navigation {
    display: flex;
    justify-content: space-between;
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid #e2e8f0;
}

.question-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 20px;
}

.q-btn {
    width: 40px;
    height: 40px;
    border: 1px solid #e2e8f0;
    background: white;
    border-radius: 5px;
    cursor: pointer;
    font-size: 14px;
}

.q-btn.answered {
    background: #667eea;
    color: white;
    border-color: #667eea;
}

.q-btn.current {
    border-color: #667eea;
    border-width: 2px;
}

/* Results */
.result-card {
    text-align: center;
    padding: 40px;
}

.score-circle {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    background: #667eea;
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 48px;
    font-weight: bold;
    margin: 20px auto;
}

/* Responsive */
@media (max-width: 768px) {
    .sidebar {
        width: 100%;
        height: auto;
        position: relative;
    }
    
    .main-content {
        margin-left: 0;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
}

/* Loading Spinner */
.spinner {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 2px solid #f3f3f3;
    border-top: 2px solid #667eea;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* Utility Classes */
.text-center { text-align: center; }
.mt-20 { margin-top: 20px; }
.mb-20 { margin-bottom: 20px; }
.hidden { display: none; }