* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: hsl(297, 70%, 50%);
    --primary-light: hsl(297, 70%, 60%);
    --primary-dark: hsl(297, 70%, 40%);
    --secondary-color: hsl(220, 15%, 25%);
    --accent-color: hsl(45, 100%, 60%);
    --text-primary: hsl(220, 15%, 15%);
    --text-secondary: hsl(220, 10%, 40%);
    --text-light: hsl(220, 5%, 60%);
    --bg-primary: hsl(0, 0%, 100%);
    --bg-secondary: hsl(220, 20%, 98%);
    --bg-tertiary: hsl(220, 15%, 96%);
    --border-color: hsl(220, 15%, 90%);
    --shadow: 0 2px 10px hsla(220, 15%, 15%, 0.1);
    --shadow-hover: 0 4px 20px hsla(220, 15%, 15%, 0.15);
    --radius: 8px;
    --radius-large: 12px;
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    --font-size-4xl: 2.5rem;
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Header */
.header {
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md) 0;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    text-decoration: none;
    color: var(--text-primary);
}

.logo, .footer-logo {
    width: 32px;
    height: 32px;
}

.brand-name, .footer-brand-name {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--primary-color);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-xl);
}

.nav-link {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    transition: color 0.2s ease;
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-color);
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    right: 0;
    height: 2px;
    background-color: var(--primary-color);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-sm);
    gap: 3px;
}

.nav-toggle span {
    width: 20px;
    height: 2px;
    background-color: var(--text-primary);
    transition: all 0.2s ease;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius);
    text-decoration: none;
    font-weight: 600;
    font-size: var(--font-size-base);
    border: 2px solid transparent;
    cursor: pointer;
    transition: all 0.2s ease;
    min-height: 44px;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background-color: var(--primary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-hover);
}

.btn-secondary {
    background-color: transparent;
    color: var(--primary-color);
    border-color: var(--primary-color);
}

.btn-secondary:hover {
    background-color: var(--primary-color);
    color: white;
}

.btn-outline {
    background-color: transparent;
    color: var(--text-primary);
    border-color: var(--border-color);
}

.btn-outline:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
    padding: var(--spacing-3xl) 0;
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-3xl);
    align-items: center;
}

.hero-title {
    font-size: var(--font-size-4xl);
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
}

.hero-description {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    line-height: 1.6;
}

.hero-actions {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.hero-image img {
    width: 100%;
    height: auto;
    border-radius: var(--radius-large);
}

/* Sections */
.section-title {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-3xl);
    color: var(--text-primary);
}

.section-footer {
    text-align: center;
    margin-top: var(--spacing-3xl);
}

/* Features */
.features {
    padding: var(--spacing-3xl) 0;
}

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

.feature-card {
    text-align: center;
    padding: var(--spacing-xl);
    background-color: var(--bg-secondary);
    border-radius: var(--radius-large);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

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

.feature-icon {
    font-size: var(--font-size-4xl);
    margin-bottom: var(--spacing-md);
}

.feature-card h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Courses */
.featured-courses {
    padding: var(--spacing-3xl) 0;
    background-color: var(--bg-secondary);
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-xl);
}

.course-card {
    background-color: var(--bg-primary);
    border-radius: var(--radius-large);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.course-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
}

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

.course-content {
    padding: var(--spacing-lg);
}

.course-meta {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
}

.course-category,
.course-difficulty {
    font-size: var(--font-size-xs);
    font-weight: 600;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.course-category {
    background-color: var(--primary-color);
    color: white;
}

.course-difficulty {
    background-color: var(--bg-tertiary);
    color: var(--text-secondary);
}

.course-title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.course-description {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
    line-height: 1.5;
}

.course-details {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
    padding-top: var(--spacing-sm);
    border-top: 1px solid var(--border-color);
}

.course-duration {
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
}

.course-price {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--primary-color);
}

/* CTA */
.cta {
    padding: var(--spacing-3xl) 0;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
    text-align: center;
}

.cta-content h2 {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    margin-bottom: var(--spacing-md);
}

.cta-content p {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-xl);
    opacity: 0.9;
}

.cta .btn-primary {
    background-color: white;
    color: var(--primary-color);
}

.cta .btn-primary:hover {
    background-color: var(--bg-secondary);
    transform: translateY(-2px);
}

/* Search and Filter */
.search-filter {
    background-color: var(--bg-secondary);
    padding: var(--spacing-xl) 0;
    border-bottom: 1px solid var(--border-color);
}

.search-controls {
    display: flex;
    gap: var(--spacing-md);
    align-items: center;
    flex-wrap: wrap;
}

.search-input,
.filter-select {
    padding: var(--spacing-sm) var(--spacing-md);
    border: 2px solid var(--border-color);
    border-radius: var(--radius);
    font-size: var(--font-size-base);
    background-color: var(--bg-primary);
    transition: border-color 0.2s ease;
    min-height: 44px;
}

.search-input {
    flex: 1;
    min-width: 250px;
}

.search-input:focus,
.filter-select:focus {
    outline: none;
    border-color: var(--primary-color);
}

/* Course Detail */
.course-detail {
    padding: var(--spacing-3xl) 0;
}

.course-header {
    margin-bottom: var(--spacing-3xl);
}

.course-main-title {
    font-size: var(--font-size-4xl);
    font-weight: 800;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.course-main-description {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
}

.course-main-meta {
    display: flex;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
}

.course-info {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: var(--spacing-3xl);
    margin-bottom: var(--spacing-3xl);
}

.course-section {
    background-color: var(--bg-secondary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-large);
    margin-bottom: var(--spacing-xl);
}

.course-section h3 {
    font-size: var(--font-size-2xl);
    font-weight: 600;
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
}

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

.course-section li {
    padding: var(--spacing-xs) 0;
    position: relative;
    padding-left: var(--spacing-lg);
}

.course-section li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
}

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

.course-card-sidebar {
    background-color: var(--bg-primary);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-large);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow);
}

.course-price-large {
    font-size: var(--font-size-4xl);
    font-weight: 800;
    color: var(--primary-color);
    margin-bottom: var(--spacing-lg);
    text-align: center;
}

.course-features {
    list-style: none;
    margin-bottom: var(--spacing-xl);
}

.course-features li {
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
}

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

.instructor-info {
    text-align: center;
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-xl);
    border-top: 1px solid var(--border-color);
}

.instructor-name {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.instructor-bio {
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
}

/* FAQ */
.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    background-color: var(--bg-secondary);
    border-radius: var(--radius);
    margin-bottom: var(--spacing-md);
    overflow: hidden;
}

.faq-question {
    width: 100%;
    padding: var(--spacing-lg);
    background: none;
    border: none;
    text-align: left;
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background-color 0.2s ease;
}

.faq-question:hover {
    background-color: var(--bg-tertiary);
}

.faq-answer {
    padding: 0 var(--spacing-lg) var(--spacing-lg);
    color: var(--text-secondary);
    line-height: 1.6;
    display: none;
}

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

.faq-toggle {
    font-size: var(--font-size-xl);
    color: var(--primary-color);
    transition: transform 0.2s ease;
}

.faq-item.active .faq-toggle {
    transform: rotate(45deg);
}

/* Forms */
.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
    color: var(--text-primary);
}

.form-input,
.form-textarea {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 2px solid var(--border-color);
    border-radius: var(--radius);
    font-size: var(--font-size-base);
    font-family: inherit;
    transition: border-color 0.2s ease;
    min-height: 44px;
}

.form-textarea {
    min-height: 120px;
    resize: vertical;
}

.form-input:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

/* Footer */
.footer {
    background-color: var(--secondary-color);
    color: white;
    padding: var(--spacing-3xl) 0 var(--spacing-xl);
}

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

.footer-brand {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.footer-brand-name {
    color: white;
}

.footer-description {
    color: hsl(220, 5%, 75%);
    line-height: 1.6;
}

.footer-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: white;
}

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

.footer-links li {
    margin-bottom: var(--spacing-sm);
}

.footer-links a {
    color: hsl(220, 5%, 75%);
    text-decoration: none;
    transition: color 0.2s ease;
}

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

.contact-info p {
    margin-bottom: var(--spacing-sm);
    color: hsl(220, 5%, 75%);
}

.contact-info a {
    color: hsl(220, 5%, 75%);
    text-decoration: none;
    transition: color 0.2s ease;
}

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

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-xl);
    border-top: 1px solid hsl(220, 15%, 35%);
    color: hsl(220, 5%, 65%);
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background-color: var(--bg-primary);
        border: 1px solid var(--border-color);
        border-top: none;
        flex-direction: column;
        padding: var(--spacing-md);
        gap: var(--spacing-md);
    }

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

    .nav-toggle {
        display: flex;
    }

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

    .hero-title {
        font-size: var(--font-size-3xl);
    }

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

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

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

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

    .course-sidebar {
        position: static;
    }

    .search-controls {
        flex-direction: column;
        align-items: stretch;
    }

    .search-input {
        min-width: auto;
    }

    .course-main-meta {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
}

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

    .hero {
        padding: var(--spacing-xl) 0;
    }

    .hero-title {
        font-size: var(--font-size-2xl);
    }

    .section-title {
        font-size: var(--font-size-2xl);
    }

    .course-main-title {
        font-size: var(--font-size-2xl);
    }

    .btn {
        padding: var(--spacing-sm);
        font-size: var(--font-size-sm);
    }

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

/* 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 */
.btn:focus,
.nav-link:focus,
.form-input:focus,
.form-textarea:focus,
.search-input:focus,
.filter-select:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}