* {
    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: #ffffff;
}

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

/* Header */
.header {
    background: #ffffff;
    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 a {
    display: flex;
    align-items: center;
    text-decoration: none;
    color: #333;
}

.logo-text {
    font-size: 1.5rem;
    font-weight: 700;
    margin-left: 0.5rem;
    color: #2563eb;
}

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

.nav-link {
    text-decoration: none;
    color: #333;
    font-weight: 500;
    transition: color 0.3s ease;
    padding: 0.5rem 0;
}

.nav-link:hover,
.nav-link.active {
    color: #2563eb;
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

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

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
    padding: 4rem 0;
    min-height: 500px;
    display: flex;
    align-items: center;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
}

.hero-title {
    font-size: 3rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 1.5rem;
    color: #1e293b;
}

.hero-description {
    font-size: 1.25rem;
    color: #64748b;
    margin-bottom: 2rem;
    line-height: 1.7;
}

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

.hero-image img {
    width: 100%;
    height: auto;
    max-width: 500px;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.875rem 2rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
    text-align: center;
    transition: all 0.3s ease;
    border: 2px solid transparent;
    cursor: pointer;
}

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

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

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

.btn-secondary:hover {
    background: #2563eb;
    color: white;
    transform: translateY(-2px);
}

.btn-outline {
    background: transparent;
    color: #64748b;
    border-color: #d1d5db;
}

.btn-outline:hover {
    background: #f8fafc;
    border-color: #2563eb;
    color: #2563eb;
}

/* Sections */
.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 3rem;
    color: #1e293b;
}

.section-actions {
    text-align: center;
    margin-top: 3rem;
}

/* Features */
.features {
    padding: 5rem 0;
    background: #ffffff;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

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

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

.feature-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 80px;
    height: 80px;
    background: #2563eb;
    color: white;
    border-radius: 50%;
    margin-bottom: 1.5rem;
}

.feature-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: #1e293b;
}

.feature-description {
    color: #64748b;
    line-height: 1.7;
}

/* Featured Courses */
.featured-courses {
    padding: 5rem 0;
    background: #f8fafc;
}

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

.course-card {
    background: white;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 6px 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 10px 25px rgba(0, 0, 0, 0.15);
}

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

.course-content {
    padding: 1.5rem;
}

.course-meta {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
}

.course-category {
    background: #e0e7ff;
    color: #3730a3;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 500;
}

.course-difficulty {
    color: #64748b;
    font-size: 0.875rem;
}

.course-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: #1e293b;
    line-height: 1.4;
}

.course-description {
    color: #64748b;
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

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

.course-price {
    font-size: 1.5rem;
    font-weight: 700;
    color: #2563eb;
}

.course-duration {
    color: #64748b;
    font-size: 0.875rem;
}

/* Trust Section */
.trust-section {
    padding: 4rem 0;
    background: white;
}

.trust-content {
    text-align: center;
}

.trust-features {
    display: flex;
    justify-content: center;
    gap: 3rem;
    margin-top: 2rem;
}

.trust-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: #2563eb;
    font-weight: 500;
}

/* Course Detail Page */
.course-hero {
    background: #1e293b;
    color: white;
    padding: 4rem 0;
}

.course-hero-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 3rem;
    align-items: start;
}

.course-hero-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.course-hero-description {
    font-size: 1.125rem;
    margin-bottom: 2rem;
    opacity: 0.9;
    line-height: 1.6;
}

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

.meta-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    opacity: 0.9;
}

.course-purchase-card {
    background: white;
    color: #333;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

.course-purchase-price {
    font-size: 2rem;
    font-weight: 700;
    color: #2563eb;
    margin-bottom: 1.5rem;
}

.course-purchase-features {
    list-style: none;
    margin-bottom: 2rem;
}

.course-purchase-features li {
    padding: 0.5rem 0;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: #64748b;
}

.course-purchase-features li::before {
    content: "✓";
    color: #10b981;
    font-weight: bold;
}

.course-details {
    padding: 4rem 0;
}

.course-details-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 4rem;
}

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

.course-section-title {
    font-size: 1.75rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: #1e293b;
}

.course-section-content ul {
    list-style: none;
    padding-left: 0;
}

.course-section-content li {
    padding: 0.75rem 0;
    border-bottom: 1px solid #e2e8f0;
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
}

.course-section-content li::before {
    content: "→";
    color: #2563eb;
    font-weight: bold;
    margin-top: 0.125rem;
}

.course-section-content li:last-child {
    border-bottom: none;
}

.instructor-card {
    background: #f8fafc;
    padding: 2rem;
    border-radius: 12px;
    margin-bottom: 2rem;
}

.instructor-name {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: #1e293b;
}

.instructor-bio {
    color: #64748b;
    line-height: 1.6;
}

/* FAQ */
.faq-item {
    background: white;
    border-radius: 8px;
    margin-bottom: 1rem;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.faq-question {
    width: 100%;
    text-align: left;
    background: none;
    border: none;
    padding: 1.5rem;
    font-size: 1.125rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: space-between;
    color: #1e293b;
}

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

.faq-answer {
    padding: 0 1.5rem 1.5rem;
    color: #64748b;
    line-height: 1.6;
    display: none;
}

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

.faq-icon {
    transition: transform 0.3s ease;
}

.faq-question.active .faq-icon {
    transform: rotate(180deg);
}

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

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

.form-input,
.form-select,
.form-textarea {
    width: 100%;
    padding: 0.875rem;
    border: 2px solid #d1d5db;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
}

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

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

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

.checkbox-group {
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    margin-bottom: 1.5rem;
}

.checkbox-input {
    margin-top: 0.25rem;
}

.checkbox-label {
    font-size: 0.875rem;
    line-height: 1.5;
    color: #374151;
}

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

.checkbox-label a:hover {
    text-decoration: underline;
}

/* Checkout */
.checkout-header {
    background: #f8fafc;
    padding: 2rem 0;
    border-bottom: 1px solid #e2e8f0;
}

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

.checkout-step {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1.5rem;
    border-radius: 25px;
    background: #e5e7eb;
    color: #6b7280;
    font-weight: 500;
}

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

.checkout-step.completed {
    background: #10b981;
    color: white;
}

.checkout-content {
    padding: 3rem 0;
}

.checkout-grid {
    display: grid;
    grid-template-columns: 1fr 400px;
    gap: 3rem;
}

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

.checkout-summary {
    background: #f8fafc;
    padding: 2rem;
    border-radius: 12px;
    height: fit-content;
    position: sticky;
    top: 100px;
}

.summary-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: #1e293b;
}

.summary-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
    border-bottom: 1px solid #e2e8f0;
}

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

.payment-methods {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin: 1.5rem 0;
    padding: 1rem;
    background: #f0f9ff;
    border-radius: 8px;
}

.payment-methods svg {
    width: 32px;
    height: 20px;
}

.security-note {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: #059669;
    font-size: 0.875rem;
    margin-top: 1rem;
}

/* Course Catalog */
.catalog-header {
    background: #f8fafc;
    padding: 3rem 0;
}

.catalog-filters {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    margin-bottom: 2rem;
}

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

.filter-select {
    padding: 0.5rem 1rem;
    border: 2px solid #d1d5db;
    border-radius: 8px;
    background: white;
    font-size: 0.875rem;
}

.search-box {
    flex: 1;
    min-width: 300px;
}

.search-input {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 2px solid #d1d5db;
    border-radius: 8px;
    font-size: 1rem;
}

.catalog-content {
    padding: 3rem 0;
}

.catalog-results {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 2rem;
    color: #64748b;
}

/* Footer */
.footer {
    background: #1e293b;
    color: white;
    padding: 3rem 0 1rem;
}

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

.footer-logo {
    display: flex;
    align-items: center;
    margin-bottom: 1rem;
}

.footer-logo-text {
    font-size: 1.25rem;
    font-weight: 600;
    margin-left: 0.5rem;
}

.footer-description {
    color: #94a3b8;
    line-height: 1.6;
    margin-bottom: 1rem;
}

.footer-title {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: white;
}

.footer-links {
    list-style: none;
}

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

.footer-links a {
    color: #94a3b8;
    text-decoration: none;
    transition: color 0.3s ease;
}

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

.contact-info p {
    color: #94a3b8;
    margin-bottom: 0.5rem;
    line-height: 1.6;
}

.contact-info a {
    color: #94a3b8;
    text-decoration: none;
}

.contact-info a:hover {
    color: white;
}

.footer-bottom {
    border-top: 1px solid #374151;
    padding-top: 2rem;
    text-align: center;
    color: #94a3b8;
}

/* Responsive Design */
@media (max-width: 1024px) {
    .checkout-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .checkout-summary {
        position: static;
    }
    
    .course-hero-content,
    .course-details-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
}

@media (max-width: 768px) {
    .nav {
        display: none;
    }
    
    .mobile-menu-toggle {
        display: flex;
    }
    
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero-title {
        font-size: 2.25rem;
    }
    
    .hero-actions {
        justify-content: center;
    }
    
    .features-grid,
    .courses-grid {
        grid-template-columns: 1fr;
    }
    
    .trust-features {
        flex-direction: column;
        gap: 1rem;
    }
    
    .catalog-filters {
        flex-direction: column;
    }
    
    .search-box {
        min-width: auto;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .checkout-steps {
        flex-direction: column;
        gap: 1rem;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero {
        padding: 2rem 0;
    }
    
    .hero-title {
        font-size: 1.875rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .btn {
        padding: 0.75rem 1.5rem;
        font-size: 0.875rem;
    }
    
    .course-card {
        margin: 0 -5px;
    }
    
    .checkout-form,
    .checkout-summary {
        padding: 1.5rem;
    }
}

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

/* Print styles */
@media print {
    .header,
    .footer,
    .hero,
    .features,
    .trust-section {
        display: none;
    }
    
    body {
        font-size: 12pt;
        line-height: 1.5;
    }
    
    .container {
        max-width: none;
        padding: 0;
    }
}