:root {
    --primary-color: #4361ee;
    --secondary-color: #3f37c9;
    --success-color: #4caf50;
    --warning-color: #ff9800;
    --danger-color: #f44336;
    --dark-color: #212529;
    --light-color: #f8f9fa;
    --gray-color: #6c757d;
    --light-gray: #e9ecef;
    --border-radius: 8px;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

body {
    font-family: 'Roboto', 'Microsoft YaHei', sans-serif;
    background-color: #f5f8ff;
    color: var(--dark-color);
    line-height: 1.6;
}

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

.card {
    background-color: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 20px;
    margin-bottom: 20px;
    transition: var(--transition);
}

.card:hover {
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.12);
}

.card-header {
    border-bottom: 1px solid var(--light-gray);
    padding-bottom: 15px;
    margin-bottom: 15px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.card-header h2 {
    color: var(--primary-color);
    font-size: 1.5rem;
    font-weight: 500;
}

.btn {
    padding: 10px 20px;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

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

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

.btn-secondary {
    background-color: var(--light-gray);
    color: var(--dark-color);
}

.btn-secondary:hover {
    background-color: #d1d5db;
}

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

.btn-success:hover {
    background-color: #3d9140;
}

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

.btn-danger:hover {
    background-color: #d32f2f;
}

.login-container {
    max-width: 400px;
    margin: 80px auto;
    padding: 30px;
}

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

.login-header h1 {
    color: var(--primary-color);
    font-size: 2rem;
    margin-bottom: 10px;
}

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

.login-option {
    padding: 20px;
    border: 2px solid var(--light-gray);
    border-radius: var(--border-radius);
    display: flex;
    align-items: center;
    cursor: pointer;
    transition: var(--transition);
}

.login-option:hover {
    border-color: var(--primary-color);
    background-color: rgba(67, 97, 238, 0.05);
}

.login-option i {
    font-size: 24px;
    color: var(--primary-color);
    margin-right: 15px;
}

.login-option-content {
    flex: 1;
}

.login-option-title {
    font-size: 1.2rem;
    font-weight: 500;
    color: var(--dark-color);
    margin-bottom: 5px;
}

.login-option-description {
    font-size: 0.9rem;
    color: var(--gray-color);
}

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

.form-label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
}

.form-control {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--light-gray);
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
}

.form-control:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.25);
}

.center-block {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
}

.camera-container {
    position: relative;
    overflow: hidden;
    border-radius: var(--border-radius);
    background-color: #000;
    width: 100%;
    padding-top: 75%; /* 4:3 比例 */
    margin-bottom: 20px;
}

#video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
}

#canvas {
    display: none;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

#face-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
}

.alert {
    padding: 15px;
    margin-bottom: 20px;
    border-radius: var(--border-radius);
}

.alert-success {
    background-color: rgba(76, 175, 80, 0.1);
    color: var(--success-color);
    border-left: 4px solid var(--success-color);
}

.alert-danger {
    background-color: rgba(244, 67, 54, 0.1);
    color: var(--danger-color);
    border-left: 4px solid var(--danger-color);
}

.module-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
    margin-top: 30px;
}

.module-card {
    border-radius: var(--border-radius);
    border: 1px solid var(--light-gray);
    overflow: hidden;
    transition: var(--transition);
}

.module-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.module-card-img {
    width: 100%;
    height: 140px;
    background-color: #eee;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    color: var(--primary-color);
}

.module-card-body {
    padding: 20px;
}

.module-card-title {
    font-size: 1.2rem;
    font-weight: 500;
    margin-bottom: 10px;
    color: var(--dark-color);
}

.module-card-text {
    color: var(--gray-color);
    margin-bottom: 15px;
    font-size: 0.9rem;
}

.navbar {
    background-color: white;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    padding: 15px 0;
    margin-bottom: 30px;
}

.navbar-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.navbar-brand {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

.navbar-nav {
    display: flex;
    align-items: center;
    gap: 15px;
}

.nav-link {
    color: var(--gray-color);
    text-decoration: none;
    transition: var(--transition);
}

.nav-link:hover {
    color: var(--primary-color);
}

.footer {
    background-color: white;
    padding: 30px 0;
    margin-top: 60px;
    border-top: 1px solid var(--light-gray);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.footer-text {
    color: var(--gray-color);
    font-size: 0.9rem;
}

@media (max-width: 768px) {
    .login-container {
        margin: 40px auto;
        padding: 20px;
    }
    
    .module-grid {
        grid-template-columns: 1fr;
    }
    
    .navbar-container {
        flex-direction: column;
        gap: 10px;
    }
    
    .footer-content {
        flex-direction: column;
        gap: 10px;
        text-align: center;
    }
}