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

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

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

/* Header */
.header {
    background: #fff;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    color: #333;
    font-weight: 700;
    font-size: 1.2rem;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-menu a {
    text-decoration: none;
    color: #333;
    font-weight: 500;
    transition: color 0.3s;
}

.nav-menu a:hover {
    color: #007bff;
}

.nav-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
}

/* Hero */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 100px 0;
    text-align: center;
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 20px;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 20px;
    font-weight: 700;
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 30px;
    opacity: 0.9;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 30px;
    text-decoration: none;
    border-radius: 5px;
    font-weight: 600;
    transition: all 0.3s;
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: #007bff;
    color: white;
}

.btn-primary:hover {
    background: #0056b3;
    transform: translateY(-2px);
}

.btn-secondary {
    background: #6c757d;
    color: white;
}

.btn-secondary:hover {
    background: #545b62;
}

/* Featured Courses */
.featured-courses {
    padding: 80px 0;
    background: #f8f9fa;
}

.featured-courses h2 {
    text-align: center;
    margin-bottom: 50px;
    font-size: 2.5rem;
    color: #333;
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 30px;
}

.course-card {
    background: white;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
    text-decoration: none;
    color: inherit;
}

.course-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.15);
}

.course-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
}

.course-content {
    padding: 25px;
}

.course-tag {
    display: inline-block;
    background: #007bff;
    color: white;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    margin-bottom: 10px;
}

.course-title {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 10px;
    color: #333;
}

.course-description {
    color: #666;
    margin-bottom: 15px;
    line-height: 1.5;
}

.course-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    font-size: 0.9rem;
    color: #666;
}

.course-price {
    font-size: 1.5rem;
    font-weight: 700;
    color: #007bff;
}

/* Trust Section */
.trust-section {
    padding: 80px 0;
    background: white;
}

.trust-section h2 {
    text-align: center;
    margin-bottom: 50px;
    font-size: 2.5rem;
    color: #333;
}

.trust-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 40px;
}

.trust-item {
    text-align: center;
    padding: 30px;
}

.trust-item h3 {
    font-size: 1.5rem;
    margin-bottom: 15px;
    color: #333;
}

.trust-item p {
    color: #666;
    line-height: 1.6;
}

/* Course Detail */
.course-detail {
    padding: 40px 0;
}

.course-header {
    background: #f8f9fa;
    padding: 60px 0;
}

.course-info {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}

.course-main h1 {
    font-size: 2.5rem;
    margin-bottom: 20px;
    color: #333;
}

.course-main p {
    font-size: 1.1rem;
    color: #666;
    margin-bottom: 20px;
}

.course-sidebar {
    background: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    height: fit-content;
}

.course-sidebar h3 {
    margin-bottom: 20px;
    color: #333;
}

.course-sidebar ul {
    list-style: none;
    margin-bottom: 20px;
}

.course-sidebar li {
    padding: 8px 0;
    border-bottom: 1px solid #eee;
    color: #666;
}

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

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: 600;
    color: #333;
}

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

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: #007bff;
    box-shadow: 0 0 0 3px rgba(0,123,255,0.1);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

.checkbox-group {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    margin: 20px 0;
}

.checkbox-group input[type="checkbox"] {
    margin-top: 4px;
    width: auto;
}

/* Checkout */
.checkout-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 40px 20px;
}

.checkout-steps {
    display: flex;
    justify-content: center;
    margin-bottom: 40px;
}

.step {
    display: flex;
    align-items: center;
    padding: 10px 20px;
    background: #f8f9fa;
    margin: 0 10px;
    border-radius: 25px;
    font-weight: 600;
}

.step.active {
    background: #007bff;
    color: white;
}

.order-summary {
    background: #f8f9fa;
    padding: 30px;
    border-radius: 10px;
    margin-bottom: 30px;
}

.payment-icons {
    display: flex;
    gap: 15px;
    align-items: center;
    margin: 20px 0;
}

.security-info {
    display: flex;
    align-items: center;
    gap: 10px;
    color: #28a745;
    font-size: 0.9rem;
    margin-top: 10px;
}

/* Footer */
.footer {
    background: #333;
    color: white;
    padding: 50px 0 20px;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
}

.footer-section h3,
.footer-section h4 {
    margin-bottom: 20px;
    color: white;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 8px;
}

.footer-section a {
    color: #ccc;
    text-decoration: none;
    transition: color 0.3s;
}

.footer-section a:hover {
    color: white;
}

.footer-bottom {
    text-align: center;
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid #555;
    color: #ccc;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }
    
    .nav-toggle {
        display: block;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .courses-grid {
        grid-template-columns: 1fr;
    }
    
    .course-info {
        grid-template-columns: 1fr;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .trust-grid {
        grid-template-columns: 1fr;
    }
}

/* Accessibility */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

button:focus,
a:focus,
input:focus,
textarea:focus,
select:focus {
    outline: 2px solid #007bff;
    outline-offset: 2px;
}

/* Error states */
.form-group.error input,
.form-group.error textarea,
.form-group.error select {
    border-color: #dc3545;
}

.error-message {
    color: #dc3545;
    font-size: 0.875rem;
    margin-top: 5px;
    display: block;
}

/* Success states */
.success-message {
    background: #d4edda;
    color: #155724;
    padding: 15px;
    border-radius: 5px;
    margin: 20px 0;
    border: 1px solid #c3e6cb;
}