/* Reset and base styles */
* {
    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;
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.5rem;
    font-weight: bold;
    color: #2563eb;
    text-decoration: none;
}

.nav ul {
    display: flex;
    list-style: none;
    gap: 2rem;
    margin: 0;
}

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

.nav a:hover,
.nav a[aria-current="page"] {
    color: #2563eb;
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    gap: 3px;
}

.mobile-menu-toggle span {
    width: 25px;
    height: 3px;
    background: #333;
    transition: 0.3s;
}

/* Hero section */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 4rem 0;
    text-align: center;
}

.hero-content h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    font-weight: 700;
}

.hero-content p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s;
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: #2563eb;
    color: white;
}

.btn-primary:hover {
    background: #1d4ed8;
    transform: translateY(-2px);
}

.btn-secondary {
    background: #6b7280;
    color: white;
}

.btn-secondary:hover {
    background: #4b5563;
}

/* Features section */
.features {
    padding: 4rem 0;
    background: #f8fafc;
}

.features h2 {
    text-align: center;
    margin-bottom: 3rem;
    font-size: 2.5rem;
    color: #1f2937;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    text-align: center;
}

.feature-card h3 {
    margin-bottom: 1rem;
    color: #2563eb;
    font-size: 1.3rem;
}

/* Courses sections */
.featured-courses,
.courses-catalog {
    padding: 4rem 0;
}

.featured-courses h2 {
    text-align: center;
    margin-bottom: 3rem;
    font-size: 2.5rem;
    color: #1f2937;
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.course-card {
    background: white;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
}

.course-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

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

.course-content {
    padding: 1.5rem;
}

.course-tag {
    display: inline-block;
    background: #eff6ff;
    color: #2563eb;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.course-title {
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
    color: #1f2937;
}

.course-title a {
    text-decoration: none;
    color: inherit;
}

.course-title a:hover {
    color: #2563eb;
}

.course-meta {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
    font-size: 0.9rem;
    color: #6b7280;
}

.course-description {
    color: #4b5563;
    margin-bottom: 1.5rem;
    line-height: 1.5;
}

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

.course-price {
    font-size: 1.5rem;
    font-weight: bold;
    color: #059669;
}

/* Catalog filters */
.catalog-filters {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    margin-bottom: 3rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
}

.filter-group {
    display: flex;
    flex-direction: column;
}

.filter-group label {
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: #374151;
}

.filter-group input,
.filter-group select {
    padding: 0.75rem;
    border: 1px solid #d1d5db;
    border-radius: 6px;
    font-size: 1rem;
}

.filter-group input:focus,
.filter-group select:focus {
    outline: none;
    border-color: #2563eb;
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

/* Course detail page */
.course-detail {
    padding: 2rem 0;
}

.course-detail-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 3rem;
    margin-bottom: 3rem;
}

.course-detail-main h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: #1f2937;
}

.course-detail-meta {
    display: flex;
    gap: 2rem;
    margin-bottom: 2rem;
    font-size: 0.9rem;
    color: #6b7280;
}

.course-detail-sidebar {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    height: fit-content;
    position: sticky;
    top: 100px;
}

.course-sections {
    margin-top: 3rem;
}

.course-section {
    margin-bottom: 3rem;
}

.course-section h2 {
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
    color: #1f2937;
}

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

.course-section li {
    padding: 0.5rem 0;
    border-bottom: 1px solid #e5e7eb;
}

.course-section li:before {
    content: "✓";
    color: #059669;
    font-weight: bold;
    margin-right: 0.5rem;
}

.curriculum-list {
    background: #f8fafc;
    border-radius: 8px;
    padding: 1.5rem;
}

.curriculum-item {
    display: flex;
    justify-content: space-between;
    padding: 0.75rem 0;
    border-bottom: 1px solid #e5e7eb;
}

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

.instructor-info {
    background: #f8fafc;
    padding: 1.5rem;
    border-radius: 8px;
    margin-bottom: 2rem;
}

.instructor-info h3 {
    margin-bottom: 0.5rem;
    color: #1f2937;
}

/* FAQ */
.faq-item {
    margin-bottom: 1rem;
    border: 1px solid #e5e7eb;
    border-radius: 8px;
    overflow: hidden;
}

.faq-question {
    width: 100%;
    padding: 1.5rem;
    background: white;
    border: none;
    text-align: left;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background-color 0.3s;
}

.faq-question:hover {
    background: #f8fafc;
}

.faq-answer {
    padding: 0 1.5rem;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
}

.faq-answer.active {
    max-height: 200px;
    padding: 1.5rem;
}

.faq-icon {
    font-size: 1.5rem;
    transition: transform 0.3s;
}

.faq-question[aria-expanded="true"] .faq-icon {
    transform: rotate(45deg);
}

/* Checkout */
.checkout {
    padding: 2rem 0;
    background: #f8fafc;
    min-height: 80vh;
}

.checkout-header {
    text-align: center;
    margin-bottom: 3rem;
}

.checkout-steps {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-top: 2rem;
}

.step {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    opacity: 0.5;
}

.step.active,
.step.completed {
    opacity: 1;
}

.step-number {
    width: 30px;
    height: 30px;
    border-radius: 50%;
    background: #e5e7eb;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
}

.step.active .step-number {
    background: #2563eb;
    color: white;
}

.step.completed .step-number {
    background: #059669;
    color: white;
}

.checkout-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 3rem;
}

.checkout-form {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.form-group {
    margin-bottom: 1.5rem;
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: #374151;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #d1d5db;
    border-radius: 6px;
    font-size: 1rem;
    transition: border-color 0.3s, box-shadow 0.3s;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #2563eb;
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.error-message {
    color: #dc2626;
    font-size: 0.9rem;
    margin-top: 0.25rem;
    display: block;
}

.form-actions {
    display: flex;
    gap: 1rem;
    justify-content: space-between;
    margin-top: 2rem;
}

.checkout-sidebar {
    height: fit-content;
    position: sticky;
    top: 100px;
}

.order-summary {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.order-summary h3 {
    margin-bottom: 1.5rem;
    color: #1f2937;
}

.order-item {
    display: flex;
    justify-content: space-between;
    padding: 1rem 0;
    border-bottom: 1px solid #e5e7eb;
}

.order-total {
    display: flex;
    justify-content: space-between;
    padding: 1rem 0;
    font-weight: bold;
    font-size: 1.2rem;
    border-top: 2px solid #2563eb;
    margin-top: 1rem;
}

/* Payment security */
.payment-security {
    text-align: center;
    margin-bottom: 2rem;
    padding: 1rem;
    background: #f0f9ff;
    border-radius: 8px;
}

.security-icons {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 0.5rem;
}

.checkbox-group {
    position: relative;
}

.checkbox-label {
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    cursor: pointer;
    font-size: 0.9rem;
    line-height: 1.4;
}

.checkbox-label input[type="checkbox"] {
    position: absolute;
    opacity: 0;
    width: 0;
    height: 0;
}

.checkmark {
    width: 20px;
    height: 20px;
    border: 2px solid #d1d5db;
    border-radius: 4px;
    flex-shrink: 0;
    position: relative;
    transition: all 0.3s;
}

.checkbox-label input:checked + .checkmark {
    background: #2563eb;
    border-color: #2563eb;
}

.checkbox-label input:checked + .checkmark:after {
    content: "✓";
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: white;
    font-weight: bold;
    font-size: 0.8rem;
}

.demo-notice {
    background: #fef3c7;
    border: 1px solid #f59e0b;
    padding: 1rem;
    border-radius: 6px;
    margin: 1.5rem 0;
}

/* Order success */
.order-success {
    padding: 4rem 0;
    text-align: center;
}

.success-content {
    max-width: 600px;
    margin: 0 auto;
}

.success-icon {
    margin-bottom: 2rem;
}

.success-content h1 {
    color: #059669;
    margin-bottom: 1rem;
    font-size: 2.5rem;
}

.success-message {
    font-size: 1.2rem;
    color: #6b7280;
    margin-bottom: 3rem;
}

.order-details {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    margin-bottom: 3rem;
    text-align: left;
}

.success-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

/* Page layouts */
.page-header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 3rem 0;
    text-align: center;
}

.page-header h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

.breadcrumb {
    padding: 1rem 0;
    color: #6b7280;
}

.breadcrumb a {
    color: #2563eb;
    text-decoration: none;
}

.breadcrumb a:hover {
    text-decoration: underline;
}

/* Content sections */
.about-content,
.contact-content,
.faq-content,
.legal-content {
    padding: 3rem 0;
}

.about-section,
.contact-grid {
    margin-bottom: 3rem;
}

.about-section h2 {
    font-size: 2rem;
    margin-bottom: 1.5rem;
    color: #1f2937;
}

.values-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.value-card {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.value-card h3 {
    color: #2563eb;
    margin-bottom: 1rem;
}

.benefits-list {
    list-style: none;
}

.benefits-list li {
    padding: 0.5rem 0;
    position: relative;
    padding-left: 1.5rem;
}

.benefits-list li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: #059669;
    font-weight: bold;
}

/* Contact page */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
}

.contact-info h2,
.contact-form-section h2 {
    margin-bottom: 2rem;
    color: #1f2937;
}

.contact-item {
    margin-bottom: 2rem;
}

.contact-item h3 {
    color: #2563eb;
    margin-bottom: 0.5rem;
}

.contact-item a {
    color: #2563eb;
    text-decoration: none;
}

.contact-item a:hover {
    text-decoration: underline;
}

.contact-form {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.contact-success {
    background: #d1fae5;
    border: 1px solid #059669;
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
}

.contact-success h3 {
    color: #059669;
    margin-bottom: 1rem;
}

/* FAQ specific */
.faq-contact {
    text-align: center;
    margin-top: 3rem;
    padding: 3rem;
    background: white;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.faq-contact h2 {
    margin-bottom: 1rem;
    color: #1f2937;
}

/* Legal pages */
.legal-document {
    background: white;
    padding: 3rem;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    max-width: 800px;
    margin: 0 auto;
}

.legal-document h2 {
    color: #1f2937;
    margin: 2rem 0 1rem 0;
    font-size: 1.5rem;
}

.legal-document ul {
    margin: 1rem 0;
    padding-left: 2rem;
}

.legal-document li {
    margin-bottom: 0.5rem;
}

/* Footer */
.footer {
    background: #1f2937;
    color: white;
    padding: 3rem 0 1rem;
    margin-top: 4rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h3,
.footer-section h4 {
    margin-bottom: 1rem;
    color: #f3f4f6;
}

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

.footer-section ul li {
    margin-bottom: 0.5rem;
}

.footer-section a {
    color: #d1d5db;
    text-decoration: none;
    transition: color 0.3s;
}

.footer-section a:hover {
    color: #2563eb;
}

.footer-bottom {
    border-top: 1px solid #374151;
    padding-top: 2rem;
    text-align: center;
    color: #9ca3af;
}

/* Utilities */
.text-center {
    text-align: center;
}

.course-not-found {
    padding: 4rem 0;
    text-align: center;
}

.course-not-found h1 {
    color: #dc2626;
    margin-bottom: 1rem;
}

/* Responsive design */
@media (max-width: 768px) {
    .mobile-menu-toggle {
        display: flex;
    }
    
    .nav {
        display: none;
    }
    
    .hero-content h1 {
        font-size: 2rem;
    }
    
    .features-grid,
    .courses-grid {
        grid-template-columns: 1fr;
    }
    
    .catalog-filters {
        grid-template-columns: 1fr;
    }
    
    .course-detail-content,
    .checkout-content,
    .contact-grid {
        grid-template-columns: 1fr;
    }
    
    .checkout-sidebar {
        position: static;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .form-actions {
        flex-direction: column;
    }
    
    .success-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
    }
    
    .checkout-steps {
        flex-direction: column;
        align-items: center;
    }
    
    .values-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero {
        padding: 2rem 0;
    }
    
    .hero-content h1 {
        font-size: 1.8rem;
    }
    
    .page-header h1 {
        font-size: 2rem;
    }
    
    .courses-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .course-card {
        margin: 0 auto;
        max-width: 100%;
    }
}

/* Focus styles for accessibility */
button:focus,
input:focus,
select:focus,
textarea:focus,
a:focus {
    outline: 2px solid #2563eb;
    outline-offset: 2px;
}

/* Print styles */
@media print {
    .header,
    .footer,
    .btn,
    .checkout-sidebar {
        display: none;
    }
    
    body {
        font-size: 12pt;
        line-height: 1.4;
    }
    
    h1, h2, h3 {
        page-break-after: avoid;
    }
}