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

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 20px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    color: #6366f1;
    font-weight: 700;
    font-size: 1.25rem;
}

.nav-menu {
    display: flex;
    gap: 2rem;
    align-items: center;
}

.nav-menu a {
    text-decoration: none;
    color: #374151;
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav-menu a:hover {
    color: #6366f1;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 4px;
}

.nav-toggle span {
    width: 25px;
    height: 3px;
    background: #374151;
    transition: 0.3s;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    text-align: center;
    transition: all 0.3s ease;
    border: 2px solid transparent;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: #6366f1;
    color: white;
    border-color: #6366f1;
}

.btn-primary:hover {
    background: #5856eb;
    border-color: #5856eb;
}

.btn-secondary {
    background: transparent;
    color: #6366f1;
    border-color: #6366f1;
}

.btn-secondary:hover {
    background: #6366f1;
    color: white;
}

.btn-outline {
    background: transparent;
    color: #374151;
    border-color: #d1d5db;
}

.btn-outline:hover {
    background: #f9fafb;
    border-color: #9ca3af;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 4rem 0;
    min-height: 600px;
    display: flex;
    align-items: center;
}

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

.hero-content h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.hero-content p {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

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

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

/* Features Section */
.features {
    padding: 5rem 0;
    background: #f8fafc;
}

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

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

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    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 {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: #1f2937;
}

.feature-card p {
    color: #6b7280;
    line-height: 1.6;
}

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

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

.section-subtitle {
    text-align: center;
    font-size: 1.25rem;
    color: #6b7280;
    margin-bottom: 3rem;
}

.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 6px rgba(0,0,0,0.05);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid #e5e7eb;
}

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

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

.course-content {
    padding: 1.5rem;
}

.course-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1rem;
}

.course-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: #1f2937;
    margin-bottom: 0.5rem;
}

.course-price {
    font-size: 1.5rem;
    font-weight: 700;
    color: #059669;
}

.course-meta {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
    font-size: 0.875rem;
    color: #6b7280;
}

.course-description {
    color: #4b5563;
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

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

.course-actions .btn {
    flex: 1;
    text-align: center;
}

.section-cta {
    text-align: center;
}

/* Trust Indicators */
.trust-indicators {
    padding: 5rem 0;
    background: #f8fafc;
}

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

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

.trust-item {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}

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

.trust-item h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: #1f2937;
}

.trust-item p {
    color: #6b7280;
    line-height: 1.6;
}

/* Course Detail Page */
.course-detail {
    padding: 3rem 0;
}

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

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

.course-detail-meta {
    display: flex;
    gap: 2rem;
    margin-bottom: 1.5rem;
    font-size: 0.875rem;
    color: #6b7280;
}

.course-detail-description {
    font-size: 1.125rem;
    color: #4b5563;
    line-height: 1.7;
    margin-bottom: 2rem;
}

.course-detail-sidebar {
    background: #f8fafc;
    padding: 2rem;
    border-radius: 12px;
    height: fit-content;
}

.course-detail-price {
    font-size: 2.5rem;
    font-weight: 700;
    color: #059669;
    margin-bottom: 1.5rem;
}

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

.course-main-content {
    display: flex;
    flex-direction: column;
    gap: 3rem;
}

.content-section {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.content-section h2 {
    font-size: 1.75rem;
    margin-bottom: 1.5rem;
    color: #1f2937;
}

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

.content-section li {
    padding: 0.5rem 0;
    padding-left: 1.5rem;
    position: relative;
}

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

.curriculum-item {
    padding: 1rem;
    border: 1px solid #e5e7eb;
    border-radius: 8px;
    margin-bottom: 1rem;
}

.curriculum-item h4 {
    font-size: 1.125rem;
    margin-bottom: 0.5rem;
    color: #1f2937;
}

.faq-item {
    border-bottom: 1px solid #e5e7eb;
    padding: 1.5rem 0;
}

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

.faq-question {
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: #1f2937;
}

.faq-answer {
    color: #4b5563;
    line-height: 1.6;
}

/* Courses Catalog */
.courses-header {
    padding: 3rem 0 2rem;
    background: #f8fafc;
}

.courses-header h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: #1f2937;
}

.courses-filters {
    padding: 2rem 0;
    background: white;
    border-bottom: 1px solid #e5e7eb;
}

.filters-row {
    display: flex;
    gap: 1rem;
    align-items: center;
    flex-wrap: wrap;
}

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

.filter-group label {
    font-weight: 500;
    color: #374151;
}

.filter-group select,
.filter-group input {
    padding: 0.5rem 1rem;
    border: 1px solid #d1d5db;
    border-radius: 6px;
    font-size: 1rem;
}

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

/* Checkout Pages */
.checkout-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 3rem 20px;
}

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

.checkout-header h1 {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: #1f2937;
}

.checkout-steps {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 3rem;
}

.step {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    background: #f3f4f6;
    color: #6b7280;
}

.step.active {
    background: #6366f1;
    color: white;
}

.checkout-form {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    margin-bottom: 2rem;
}

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

.form-section h3 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: #1f2937;
}

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

.form-group {
    margin-bottom: 1rem;
}

.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: 0.75rem;
    border: 1px solid #d1d5db;
    border-radius: 6px;
    font-size: 1rem;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #6366f1;
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.form-group.error input {
    border-color: #ef4444;
}

.error-message {
    color: #ef4444;
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

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

.order-summary h3 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: #1f2937;
}

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

.summary-total {
    display: flex;
    justify-content: space-between;
    font-weight: 700;
    font-size: 1.25rem;
    color: #1f2937;
}

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

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

.security-notice {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: #059669;
    font-size: 0.875rem;
    margin: 1rem 0;
}

.checkbox-group {
    display: flex;
    align-items: flex-start;
    gap: 0.5rem;
    margin: 1.5rem 0;
}

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

.checkout-actions {
    display: flex;
    gap: 1rem;
    justify-content: space-between;
}

/* Success Page */
.success-container {
    max-width: 600px;
    margin: 0 auto;
    padding: 3rem 20px;
    text-align: center;
}

.success-icon {
    font-size: 4rem;
    color: #059669;
    margin-bottom: 1rem;
}

.success-container h1 {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: #1f2937;
}

.success-container p {
    font-size: 1.125rem;
    color: #6b7280;
    margin-bottom: 2rem;
}

/* Content Pages */
.content-page {
    padding: 3rem 0;
    max-width: 800px;
    margin: 0 auto;
}

.content-page h1 {
    font-size: 2.5rem;
    margin-bottom: 2rem;
    color: #1f2937;
}

.content-page h2 {
    font-size: 1.75rem;
    margin: 2rem 0 1rem;
    color: #1f2937;
}

.content-page h3 {
    font-size: 1.25rem;
    margin: 1.5rem 0 0.75rem;
    color: #1f2937;
}

.content-page p {
    margin-bottom: 1rem;
    line-height: 1.7;
    color: #4b5563;
}

.content-page ul {
    margin-bottom: 1rem;
    padding-left: 2rem;
}

.content-page li {
    margin-bottom: 0.5rem;
    color: #4b5563;
}

/* Contact Form */
.contact-info {
    background: #f8fafc;
    padding: 2rem;
    border-radius: 12px;
    margin-bottom: 3rem;
}

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

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

.contact-item {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.contact-item-icon {
    width: 40px;
    height: 40px;
    background: #6366f1;
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
}

.contact-item-content h3 {
    font-size: 1rem;
    margin-bottom: 0.25rem;
    color: #1f2937;
}

.contact-item-content p {
    color: #6b7280;
    margin: 0;
}

.contact-item-content a {
    color: #6366f1;
    text-decoration: none;
}

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

/* Footer */
footer {
    background: #1f2937;
    color: white;
    padding: 3rem 0 1rem;
    margin-top: 5rem;
}

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

.footer-section h4 {
    font-size: 1.125rem;
    margin-bottom: 1rem;
    color: white;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 1rem;
    font-weight: 700;
    font-size: 1.25rem;
}

.footer-section p {
    color: #d1d5db;
    line-height: 1.6;
    margin-bottom: 1rem;
}

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

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

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

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

.footer-bottom {
    border-top: 1px solid #374151;
    padding-top: 2rem;
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    flex-wrap: wrap;
    gap: 1rem;
}

.footer-contact {
    color: #d1d5db;
    font-size: 0.875rem;
}

.footer-contact p {
    margin-bottom: 0.25rem;
}

.footer-contact a {
    color: #d1d5db;
    text-decoration: none;
}

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

.footer-copyright {
    color: #9ca3af;
    font-size: 0.875rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 1rem;
        box-shadow: 0 2px 10px rgba(0,0,0,0.1);
        gap: 1rem;
    }

    .nav-menu.active {
        display: flex;
    }

    .nav-toggle {
        display: flex;
    }

    .hero .container {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-content h1 {
        font-size: 2rem;
    }

    .hero-cta {
        justify-content: center;
    }

    .features h2,
    .featured-courses h2,
    .trust-indicators h2 {
        font-size: 2rem;
    }

    .courses-grid {
        grid-template-columns: 1fr;
    }

    .course-card {
        max-width: 100%;
    }

    .course-detail-header {
        grid-template-columns: 1fr;
    }

    .course-sections {
        grid-template-columns: 1fr;
    }

    .filters-row {
        flex-direction: column;
        align-items: stretch;
    }

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

    .checkout-actions {
        flex-direction: column;
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }

    .contact-details {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }

    .hero-content h1 {
        font-size: 1.75rem;
    }

    .hero-content p {
        font-size: 1rem;
    }

    .hero-cta {
        flex-direction: column;
    }

    .checkout-steps {
        flex-direction: column;
        align-items: center;
    }

    .courses-grid {
        grid-template-columns: 1fr;
    }

    .course-card {
        margin: 0;
    }
}

/* Focus states for accessibility */
button:focus,
.btn:focus,
input:focus,
select:focus,
textarea:focus {
    outline: 2px solid #6366f1;
    outline-offset: 2px;
}

/* Loading states */
.loading {
    opacity: 0.6;
    pointer-events: none;
}

/* Error states */
.error {
    color: #ef4444;
    border-color: #ef4444;
}

.success {
    color: #059669;
    border-color: #059669;
}