/* Base styles */
:root {
    --primary: #2196F3;
    --primary-dark: #1976D2;
    --secondary: #4CAF50;
    --dark: #333;
    --light: #f8f9fa;
    --gray: #6c757d;
    --light-gray: #e9ecef;
    --border: #dee2e6;
    --success: #28a745;
    --danger: #dc3545;
    --warning: #ffc107;
    --white: #fff;
    --shadow: 0 4px 12px rgba(0,0,0,0.1);
    --radius: 8px;
    --transition: all 0.3s ease;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    line-height: 1.6;
    color: var(--dark);
    background-color: var(--light);
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    margin-bottom: 1rem;
    font-weight: 600;
}

h1 {
    font-size: 2.5rem;
}

h2 {
    font-size: 2rem;
}

h3 {
    font-size: 1.5rem;
}

p {
    margin-bottom: 1rem;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 10px 20px;
    border-radius: var(--radius);
    text-decoration: none;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    font-size: 1rem;
}

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

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

.btn-outline {
    background-color: transparent;
    border: 2px solid var(--primary);
    color: var(--primary);
}

.btn-outline:hover {
    background-color: var(--primary);
    color: var(--white);
}

.btn-sm {
    padding: 6px 12px;
    font-size: 0.875rem;
}

.btn-success {
    background-color: var(--success);
    color: var(--white);
}

.btn-success:hover {
    opacity: 0.9;
}

.btn-danger {
    background-color: var(--danger);
    color: var(--white);
}

.btn-danger:hover {
    opacity: 0.9;
}

/* Header */
.main-header {
    background-color: var(--white);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.main-header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
}

.logo h1 {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--dark);
}

.logo span {
    color: var(--primary);
}

.auth-links a {
    margin-left: 15px;
    text-decoration: none;
    color: var(--dark);
    font-weight: 500;
}

.auth-links .btn {
    background-color: var(--primary);
    color: var(--white);
}

.user-menu {
    display: flex;
    align-items: center;
    gap: 15px;
}

.user-menu a {
    text-decoration: none;
    color: var(--dark);
    font-weight: 500;
    padding: 5px 10px;
    border-radius: var(--radius);
}

.user-menu a.active, .user-menu a:hover {
    background-color: var(--light-gray);
}

/* Hero section */
.hero {
    padding: 80px 0;
    text-align: center;
    background: linear-gradient(135deg, #f5f7fa 0%, #e4edf9 100%);
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 20px;
    color: var(--dark);
}

.hero p {
    font-size: 1.2rem;
    max-width: 700px;
    margin: 0 auto 30px;
    color: var(--gray);
}

.cta-buttons {
    display: flex;
    justify-content: center;
    gap: 20px;
}

/* Features */
.features {
    padding: 60px 0;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

.feature-card {
    background: var(--white);
    padding: 30px;
    border-radius: var(--radius);
    text-align: center;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

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

.feature-card i {
    font-size: 2.5rem;
    color: var(--primary);
    margin-bottom: 20px;
}

.feature-card h3 {
    margin-bottom: 15px;
    color: var(--dark);
}

/* Test levels */
.test-levels {
    padding: 60px 0;
    background-color: var(--white);
}

.levels-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-top: 40px;
}

.level-card {
    background: linear-gradient(135deg, #f5f7fa 0%, #e4edf9 100%);
    padding: 30px;
    border-radius: var(--radius);
    text-align: center;
    transition: var(--transition);
}

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

.level-card h3 {
    color: var(--dark);
    margin-bottom: 10px;
}

.level-card p {
    color: var(--gray);
    margin-bottom: 20px;
}

/* Auth pages */
.auth-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
    background: linear-gradient(135deg, #f5f7fa 0%, #e4edf9 100%);
}

.auth-box {
    background: var(--white);
    padding: 40px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    width: 100%;
    max-width: 500px;
}

.auth-box h2 {
    text-align: center;
    margin-bottom: 30px;
    color: var(--dark);
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--dark);
}

.form-group input {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 1rem;
    transition: var(--transition);
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(33, 150, 243, 0.2);
}

.auth-footer {
    text-align: center;
    margin-top: 20px;
}

.auth-footer a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
}

/* Alerts */
.alert {
    padding: 15px;
    border-radius: var(--radius);
    margin-bottom: 20px;
    font-weight: 500;
}

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

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

/* Dashboard */
.dashboard {
    padding: 40px 0;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin: 30px 0;
}

.stat-card {
    background: var(--white);
    padding: 20px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    text-align: center;
}

.stat-value {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary);
    margin: 10px 0;
}

.chart-container {
    background: var(--white);
    padding: 30px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    margin: 40px 0;
    height: 400px;
}

.certificates-section, .profile-section {
    margin: 40px 0;
}

.certificates-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.certificate-card {
    background: var(--white);
    padding: 20px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.cert-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
}

.cert-header h3 {
    color: var(--dark);
}

.cert-date {
    color: var(--gray);
    font-size: 0.9rem;
}

.cert-stats {
    display: flex;
    justify-content: space-between;
    margin: 20px 0;
}

.stat {
    text-align: center;
}

.stat span {
    display: block;
    color: var(--gray);
    font-size: 0.9rem;
}

.stat strong {
    font-size: 1.2rem;
    color: var(--dark);
}

.cert-actions {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.cert-id {
    font-size: 0.9rem;
    color: var(--gray);
}

.profile-info {
    background: var(--white);
    padding: 20px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    margin: 20px 0;
}

.profile-item {
    display: flex;
    justify-content: space-between;
    padding: 10px 0;
    border-bottom: 1px solid var(--border);
}

.profile-item:last-child {
    border-bottom: none;
}

/* Test page */
.test-page {
    padding: 40px 0;
}

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

.test-header h1 {
    color: var(--dark);
}

.test-header p {
    color: var(--gray);
    font-size: 1.1rem;
}

.test-container {
    background: var(--white);
    padding: 30px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    margin-bottom: 30px;
}

.timer {
    text-align: right;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 20px;
    font-size: 1.2rem;
}

.paragraph {
    background: var(--light-gray);
    padding: 20px;
    border-radius: var(--radius);
    margin-bottom: 20px;
    min-height: 120px;
    font-size: 1.1rem;
    line-height: 1.8;
}

#user-input {
    width: 100%;
    min-height: 150px;
    padding: 15px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 1.1rem;
    line-height: 1.8;
    resize: vertical;
}

.login-prompt {
    margin-top: 15px;
    text-align: center;
    color: var(--gray);
}

.login-prompt a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
}

.test-stats {
    display: flex;
    justify-content: center;
    gap: 30px;
    margin: 30px 0;
}

.test-stats .stat {
    text-align: center;
}

.test-stats .stat span {
    display: block;
    color: var(--gray);
    margin-bottom: 5px;
}

.test-stats .stat strong {
    font-size: 1.5rem;
    color: var(--dark);
}

.test-actions {
    text-align: center;
    margin-top: 20px;
}

/* Results page */
.results-page {
    padding: 40px 0;
}

.result-card {
    background: var(--white);
    padding: 40px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.result-header h2 {
    color: var(--dark);
    margin-bottom: 10px;
}

.result-header p {
    color: var(--gray);
    font-size: 1.1rem;
}

.result-stats {
    display: flex;
    justify-content: center;
    gap: 40px;
    margin: 40px 0;
}

.result-stats .stat {
    text-align: center;
}

.stat-value {
    font-size: 3rem;
    font-weight: 700;
    color: var(--primary);
}

.stat-label {
    font-size: 1.1rem;
    color: var(--gray);
    text-transform: uppercase;
}

.result-actions {
    margin-top: 40px;
}

.notice {
    font-size: 1.1rem;
    color: var(--gray);
    margin: 20px 0;
}

.auth-buttons {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-top: 20px;
}

/* Admin dashboard */
.admin-dashboard .stats-grid {
    margin: 30px 0 50px;
}

.activity-section {
    margin-bottom: 50px;
}

.activity-card {
    background: var(--white);
    padding: 30px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.activity-card ul {
    list-style: none;
}

.activity-card li {
    padding: 10px 0;
    border-bottom: 1px solid var(--border);
}

.activity-card li:last-child {
    border-bottom: none;
}

.actions-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
}

.action-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: var(--white);
    padding: 30px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    text-decoration: none;
    color: var(--dark);
    transition: var(--transition);
    height: 150px;
}

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

.action-card i {
    font-size: 2.5rem;
    color: var(--primary);
    margin-bottom: 15px;
}

/* Tables */
.users-table table, .certificates-table table {
    width: 100%;
    border-collapse: collapse;
    background: var(--white);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
}

.users-table th, .users-table td,
.certificates-table th, .certificates-table td {
    padding: 15px;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

.users-table th, .certificates-table th {
    background-color: var(--light-gray);
    font-weight: 600;
}

.status-badge {
    padding: 5px 10px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
}

.status-active {
    background-color: rgba(40, 167, 69, 0.2);
    color: var(--success);
}

.status-pending {
    background-color: rgba(255, 193, 7, 0.2);
    color: var(--warning);
}

.status-rejected {
    background-color: rgba(220, 53, 69, 0.2);
    color: var(--danger);
}

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

.modal-content {
    background-color: var(--white);
    margin: 5% auto;
    padding: 30px;
    border-radius: var(--radius);
    width: 90%;
    max-width: 600px;
    position: relative;
}

.close {
    color: var(--gray);
    float: right;
    font-size: 1.5rem;
    font-weight: bold;
    cursor: pointer;
    position: absolute;
    right: 20px;
    top: 15px;
}

.close:hover {
    color: var(--dark);
}

/* Footer */
footer {
    background-color: var(--dark);
    color: var(--white);
    padding: 30px 0;
    margin-top: 60px;
}

footer .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-links a {
    color: var(--light-gray);
    text-decoration: none;
    margin-left: 20px;
}

.footer-links a:hover {
    color: var(--white);
}

/* Responsive */
@media (max-width: 768px) {
    .main-header .container {
        flex-direction: column;
        gap: 15px;
    }
    
    .hero h1 {
        font-size: 2.2rem;
    }
    
    .cta-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .test-stats {
        flex-direction: column;
        gap: 20px;
    }
    
    .result-stats {
        flex-direction: column;
        gap: 30px;
    }
    
    footer .container {
        flex-direction: column;
        gap: 20px;
        text-align: center;
    }
    
    .footer-links {
        display: flex;
        flex-wrap: wrap;
        justify-content: center;
    }
}