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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

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;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    margin-bottom: 1rem;
}

h1 {
    font-size: 2.5rem;
    color: #1a1a1a;
}

h2 {
    font-size: 2rem;
    color: #1a1a1a;
}

h3 {
    font-size: 1.5rem;
    color: #2a2a2a;
}

p {
    margin-bottom: 1rem;
    color: #555;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 500;
    text-align: center;
    transition: all 0.3s ease;
    border: 2px solid transparent;
    cursor: pointer;
    font-size: 16px;
}

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

.btn-primary:hover {
    background-color: #1d4ed8;
    border-color: #1d4ed8;
}

.btn-outline {
    background-color: transparent;
    color: #2563eb;
    border-color: #2563eb;
}

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

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

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

/* Header */
.header {
    background-color: #fff;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

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

.logo a {
    display: flex;
    align-items: center;
    text-decoration: none;
    color: #1a1a1a;
    font-weight: 700;
    font-size: 1.25rem;
}

.logo img {
    margin-right: 10px;
}

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

.nav a {
    text-decoration: none;
    color: #555;
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav a:hover {
    color: #2563eb;
}

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: 5px;
}

.mobile-menu-btn span {
    width: 25px;
    height: 3px;
    background-color: #333;
    margin: 3px 0;
    transition: 0.3s;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
    padding: 80px 0;
    position: relative;
    overflow: hidden;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1.5rem;
}

.hero p {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    color: #666;
}

.hero-actions {
    display: flex;
    gap: 1rem;
}

.hero-image img {
    width: 100%;
    height: auto;
}

/* Features Section */
.features {
    padding: 80px 0;
    background-color: #fff;
}

.features h2 {
    text-align: center;
    margin-bottom: 3rem;
}

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

.feature {
    text-align: center;
    padding: 2rem;
    border-radius: 12px;
    background-color: #f8fafc;
    transition: transform 0.3s ease;
}

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

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

/* Courses Section */
.featured-courses, .courses-page {
    padding: 80px 0;
    background-color: #f8fafc;
}

.featured-courses h2, .courses-page h1 {
    text-align: center;
    margin-bottom: 3rem;
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.course-card {
    background-color: #fff;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.course-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.15);
}

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

.course-content {
    padding: 1.5rem;
}

.course-meta {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
    font-size: 0.875rem;
    color: #666;
}

.course-title {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}

.course-title a {
    text-decoration: none;
    color: #1a1a1a;
}

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

.course-description {
    color: #666;
    margin-bottom: 1rem;
    font-size: 0.875rem;
}

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

.course-price {
    font-size: 1.25rem;
    font-weight: 600;
    color: #2563eb;
}

/* Course Filters */
.course-filters {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
    align-items: center;
}

.filter-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.filter-group label {
    font-weight: 500;
    color: #555;
}

.filter-group select,
.filter-group input {
    padding: 8px 12px;
    border: 1px solid #d1d5db;
    border-radius: 6px;
    font-size: 14px;
}

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

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

.course-header h1 {
    margin-bottom: 1rem;
}

.course-header-meta {
    display: flex;
    gap: 2rem;
    margin-bottom: 1rem;
    flex-wrap: wrap;
}

.course-header-meta span {
    color: #666;
    font-size: 0.875rem;
}

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

.course-main img {
    width: 100%;
    height: 300px;
    object-fit: cover;
    border-radius: 12px;
    margin-bottom: 2rem;
}

.course-section {
    margin-bottom: 2rem;
}

.course-section h3 {
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid #e5e7eb;
}

.course-section ul {
    padding-left: 1.5rem;
}

.course-section li {
    margin-bottom: 0.5rem;
    color: #555;
}

.curriculum-item {
    padding: 1rem;
    background-color: #f8fafc;
    border-radius: 8px;
    margin-bottom: 0.5rem;
}

.curriculum-item h4 {
    margin-bottom: 0.5rem;
    color: #1a1a1a;
}

.curriculum-item p {
    font-size: 0.875rem;
    color: #666;
    margin: 0;
}

.course-sidebar {
    background-color: #fff;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    height: fit-content;
    position: sticky;
    top: 100px;
}

.price-section {
    text-align: center;
    margin-bottom: 2rem;
}

.price-section .price {
    font-size: 2rem;
    font-weight: 700;
    color: #2563eb;
    margin-bottom: 1rem;
}

.instructor-section {
    margin-bottom: 2rem;
    padding-top: 2rem;
    border-top: 1px solid #e5e7eb;
}

.instructor-section h4 {
    margin-bottom: 0.5rem;
}

.instructor-section p {
    font-size: 0.875rem;
    color: #666;
}

/* FAQ Section */
.faq-item {
    background-color: #fff;
    border-radius: 8px;
    margin-bottom: 1rem;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
}

.faq-question {
    padding: 1.5rem;
    cursor: pointer;
    border: none;
    background: none;
    width: 100%;
    text-align: left;
    font-size: 1rem;
    font-weight: 500;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.faq-answer {
    padding: 0 1.5rem 1.5rem;
    color: #666;
    display: none;
}

.faq-answer.active {
    display: block;
}

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

.trust-section h2 {
    text-align: center;
    margin-bottom: 3rem;
}

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

.trust-item {
    text-align: center;
    padding: 2rem;
}

.trust-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: #374151;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px;
    border: 1px solid #d1d5db;
    border-radius: 6px;
    font-size: 16px;
    transition: border-color 0.3s ease;
}

.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);
}

.form-group.error input,
.form-group.error select,
.form-group.error textarea {
    border-color: #dc2626;
}

.error-message {
    color: #dc2626;
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

.checkbox-group {
    display: flex;
    align-items: flex-start;
    gap: 0.5rem;
}

.checkbox-group input[type="checkbox"] {
    width: auto;
    margin-top: 0.25rem;
}

.checkbox-group label {
    margin-bottom: 0;
    font-size: 0.875rem;
}

/* Checkout */
.checkout-page {
    padding: 40px 0;
}

.checkout-steps {
    display: flex;
    justify-content: center;
    margin-bottom: 3rem;
}

.step {
    display: flex;
    align-items: center;
    padding: 1rem 2rem;
    background-color: #f3f4f6;
    color: #6b7280;
    border-radius: 50px;
    margin: 0 0.5rem;
    font-weight: 500;
}

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

.checkout-content {
    max-width: 600px;
    margin: 0 auto;
    background-color: #fff;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
}

.order-summary {
    background-color: #f8fafc;
    padding: 2rem;
    border-radius: 12px;
    margin-bottom: 2rem;
}

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

.order-item:last-child {
    border-bottom: none;
    font-weight: 600;
    font-size: 1.125rem;
}

.payment-icons {
    display: flex;
    gap: 1rem;
    align-items: center;
    margin: 1rem 0;
}

.payment-icon {
    width: 40px;
    height: 25px;
    background-color: #f3f4f6;
    border-radius: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    font-weight: 600;
    color: #6b7280;
}

/* Footer */
.footer {
    background-color: #1f2937;
    color: #d1d5db;
    padding: 60px 0 20px;
}

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

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

.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 ease;
}

.footer-section a:hover {
    color: #60a5fa;
}

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

/* Section Footer */
.section-footer {
    text-align: center;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav {
        display: none;
    }
    
    .mobile-menu-btn {
        display: flex;
    }
    
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .hero-actions {
        justify-content: center;
    }
    
    .features-grid,
    .courses-grid,
    .trust-grid {
        grid-template-columns: 1fr;
    }
    
    .course-detail-content {
        grid-template-columns: 1fr;
    }
    
    .course-sidebar {
        position: static;
    }
    
    .course-filters {
        flex-direction: column;
        align-items: stretch;
    }
    
    .checkout-steps {
        flex-direction: column;
        align-items: center;
    }
    
    .step {
        margin: 0.25rem 0;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero {
        padding: 40px 0;
    }
    
    .features,
    .featured-courses,
    .trust-section {
        padding: 40px 0;
    }
    
    .btn {
        padding: 10px 20px;
        font-size: 14px;
    }
    
    .hero-actions {
        flex-direction: column;
        gap: 0.5rem;
    }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

.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;
}

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