* {
    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: 1000;
}

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

.nav-brand {
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo {
    width: 40px;
    height: 40px;
}

.brand-name {
    font-size: 1.5rem;
    font-weight: 700;
    color: #6366f1;
}

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

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

.nav-link:hover,
.nav-link.active {
    color: #6366f1;
}

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

.nav-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: 60vh;
    display: flex;
    align-items: center;
}

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

.hero h1 {
    font-size: 3rem;
    font-weight: 800;
    color: #1e293b;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero p {
    font-size: 1.2rem;
    color: #64748b;
    margin-bottom: 2rem;
}

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

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

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    text-align: center;
    transition: all 0.3s;
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

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

.btn-primary:hover {
    background: #5b5bd6;
    transform: translateY(-2px);
}

.btn-secondary {
    background: transparent;
    color: #6366f1;
    border: 2px solid #6366f1;
}

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

/* Sections */
section {
    padding: 4rem 0;
}

section h2 {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 3rem;
    color: #1e293b;
}

/* Features */
.features {
    background: #f8fafc;
}

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

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    text-align: center;
    transition: transform 0.3s;
}

.feature-card:hover {
    transform: translateY(-4px);
}

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

.feature-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: #1e293b;
}

.feature-card p {
    color: #64748b;
}

/* Courses Grid */
.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, box-shadow 0.3s;
}

.course-card:hover {
    transform: translateY(-4px);
    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-meta {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
    font-size: 0.9rem;
    color: #64748b;
}

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

.course-description {
    color: #64748b;
    margin-bottom: 1rem;
    line-height: 1.5;
}

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

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

.course-label {
    background: #6366f1;
    color: white;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
}

/* Trust Section */
.trust-section {
    background: #f8fafc;
}

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

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

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

.trust-item h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: #1e293b;
}

.trust-item p {
    color: #64748b;
}

/* Section CTA */
.section-cta {
    text-align: center;
    margin-top: 3rem;
}

/* Course Filters */
.course-filters {
    background: #f8fafc;
    padding: 2rem;
    border-radius: 12px;
    margin-bottom: 3rem;
}

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

.filter-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.filter-group label {
    font-weight: 600;
    color: #374151;
}

.filter-input {
    padding: 8px 12px;
    border: 2px solid #e5e7eb;
    border-radius: 6px;
    font-size: 1rem;
}

.filter-input:focus {
    outline: none;
    border-color: #6366f1;
}

/* Course Detail */
.course-detail {
    max-width: 1000px;
    margin: 0 auto;
    padding: 2rem 20px;
}

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

.course-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: #1e293b;
}

.course-header .course-meta {
    justify-content: center;
    margin-bottom: 2rem;
}

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

.course-main {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

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

.course-section h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: #1e293b;
}

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

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

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

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

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

.purchase-price {
    font-size: 3rem;
    font-weight: 700;
    color: #059669;
    margin-bottom: 1rem;
}

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

.instructor-info h4 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: #1e293b;
}

/* Forms */
.form-container {
    max-width: 600px;
    margin: 0 auto;
    padding: 2rem;
}

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

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

.form-input {
    width: 100%;
    padding: 12px;
    border: 2px solid #e5e7eb;
    border-radius: 6px;
    font-size: 1rem;
    transition: border-color 0.3s;
}

.form-input:focus {
    outline: none;
    border-color: #6366f1;
}

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

.error-message {
    color: #ef4444;
    font-size: 0.9rem;
    margin-top: 0.25rem;
}

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

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

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

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

.summary-row {
    display: flex;
    justify-content: space-between;
    margin-bottom: 1rem;
}

.summary-total {
    font-size: 1.25rem;
    font-weight: 700;
    padding-top: 1rem;
    border-top: 2px solid #e5e7eb;
}

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

.payment-icon {
    width: 40px;
    height: 25px;
}

/* 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-section h4 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

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

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

.footer-section a {
    color: #cbd5e1;
    text-decoration: none;
    transition: color 0.3s;
}

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

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid #374151;
    color: #cbd5e1;
}

/* Success Page */
.success-container {
    max-width: 600px;
    margin: 2rem auto;
    padding: 3rem 2rem;
    background: white;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    text-align: center;
}

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

.success-container h1 {
    color: #1e293b;
    margin-bottom: 1rem;
}

.order-details {
    background: #f8fafc;
    padding: 2rem;
    border-radius: 8px;
    margin: 2rem 0;
    text-align: left;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .hero .container {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .hero-cta {
        justify-content: center;
    }
    
    .courses-grid {
        grid-template-columns: 1fr;
    }
    
    .course-sections {
        grid-template-columns: 1fr;
    }
    
    .course-sidebar {
        position: static;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .filter-row {
        flex-direction: column;
        align-items: stretch;
    }
    
    .filter-group {
        width: 100%;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero {
        padding: 2rem 0;
    }
    
    section {
        padding: 2rem 0;
    }
    
    section h2 {
        font-size: 2rem;
    }
    
    .feature-card,
    .course-section {
        padding: 1.5rem;
    }
}

/* 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;
}

/* Focus states */
.btn:focus,
.nav-link:focus,
.form-input:focus {
    outline: 2px solid #6366f1;
    outline-offset: 2px;
}

/* Print styles */
@media print {
    .header,
    .footer,
    .nav-toggle,
    .btn {
        display: none;
    }
    
    body {
        font-size: 12pt;
        line-height: 1.4;
    }
    
    .container {
        max-width: none;
        padding: 0;
    }
}