:root {
    --primary-color: hsl(297, 70%, 50%);
    --primary-light: hsl(297, 70%, 60%);
    --primary-dark: hsl(297, 70%, 40%);
    --secondary-color: hsl(210, 15%, 25%);
    --accent-color: hsl(45, 100%, 60%);
    --text-primary: hsl(210, 15%, 15%);
    --text-secondary: hsl(210, 10%, 45%);
    --text-light: hsl(210, 5%, 65%);
    --bg-primary: hsl(0, 0%, 100%);
    --bg-secondary: hsl(210, 20%, 98%);
    --bg-tertiary: hsl(210, 15%, 95%);
    --border-color: hsl(210, 15%, 90%);
    --border-light: hsl(210, 10%, 95%);
    --shadow-sm: 0 1px 3px hsla(210, 15%, 15%, 0.1);
    --shadow-md: 0 4px 6px hsla(210, 15%, 15%, 0.1);
    --shadow-lg: 0 10px 25px hsla(210, 15%, 15%, 0.1);
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --font-mono: "SF Mono", Monaco, "Cascadia Code", "Roboto Mono", Consolas, "Courier New", monospace;
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    margin: 0;
    padding: 0;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.3;
    margin: 0 0 1rem 0;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

p {
    margin: 0 0 1rem 0;
    color: var(--text-secondary);
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.2s ease;
}

a:hover {
    color: var(--primary-dark);
}

a:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border: 2px solid transparent;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.2s ease;
    min-height: 48px;
}

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

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

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

.btn-secondary:hover {
    background-color: hsl(210, 15%, 20%);
    color: white;
}

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

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

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

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

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem;
    min-height: 70px;
}

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

.brand-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-primary);
    font-weight: 600;
    font-size: 1.25rem;
}

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

.nav-menu {
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
    gap: 2rem;
}

.nav-link {
    color: var(--text-secondary);
    font-weight: 500;
    padding: 0.5rem 0;
    position: relative;
}

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

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -1rem;
    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: 0.5rem;
    gap: 4px;
}

.nav-toggle span {
    width: 25px;
    height: 3px;
    background-color: var(--text-primary);
    transition: all 0.2s ease;
}

/* Hero */
.hero {
    padding: 4rem 0;
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
}

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

.hero-content h1 {
    font-size: 3rem;
    color: var(--text-primary);
    margin-bottom: 1.5rem;
}

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

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

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

/* Trust Indicators */
.trust-indicators {
    padding: 3rem 0;
    background-color: var(--bg-secondary);
}

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

.trust-item {
    text-align: center;
    padding: 1.5rem;
}

.trust-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.trust-item h3 {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

/* Courses */
.featured-courses {
    padding: 4rem 0;
}

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

.section-header h2 {
    font-size: 2.5rem;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

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

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

.course-card {
    background-color: var(--bg-primary);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-sm);
}

.course-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.course-image {
    width: 100%;
    height: 200px;
    overflow: hidden;
}

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

.course-content {
    padding: 1.5rem;
}

.course-meta {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
    font-size: 0.875rem;
}

.course-category {
    background-color: var(--primary-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-sm);
    font-weight: 500;
}

.course-difficulty {
    color: var(--text-light);
}

.course-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.course-title a {
    color: inherit;
}

.course-title a:hover {
    color: var(--primary-color);
}

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

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

.course-price {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary-color);
}

.course-duration {
    color: var(--text-light);
    font-size: 0.875rem;
}

/* Course Details */
.course-hero {
    padding: 3rem 0;
    background-color: var(--bg-secondary);
}

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

.course-info h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.course-stats {
    display: flex;
    gap: 2rem;
    margin: 1.5rem 0;
    flex-wrap: wrap;
}

.stat-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-secondary);
}

.course-sidebar {
    background-color: var(--bg-primary);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-lg);
    padding: 2rem;
    height: fit-content;
    box-shadow: var(--shadow-md);
}

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

.current-price {
    font-size: 2.5rem;
    font-weight: 600;
    color: var(--primary-color);
}

.course-details {
    padding: 3rem 0;
}

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

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

.details-section h2 {
    color: var(--text-primary);
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--border-light);
}

.learning-objectives {
    list-style: none;
    padding: 0;
}

.learning-objectives li {
    padding: 0.5rem 0;
    position: relative;
    padding-left: 2rem;
}

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

.curriculum-list {
    list-style: none;
    padding: 0;
}

.curriculum-item {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-md);
    padding: 1rem;
    margin-bottom: 0.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.lesson-title {
    font-weight: 500;
    color: var(--text-primary);
}

.lesson-duration {
    color: var(--text-light);
    font-size: 0.875rem;
}

.instructor-card {
    background-color: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    text-align: center;
}

.instructor-name {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.faq-list {
    list-style: none;
    padding: 0;
}

.faq-item {
    border: 1px solid var(--border-light);
    border-radius: var(--radius-md);
    margin-bottom: 1rem;
    overflow: hidden;
}

.faq-question {
    background-color: var(--bg-secondary);
    padding: 1rem;
    font-weight: 500;
    color: var(--text-primary);
    cursor: pointer;
    user-select: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.faq-question::after {
    content: '+';
    font-size: 1.25rem;
    color: var(--primary-color);
}

.faq-question.active::after {
    content: '−';
}

.faq-answer {
    padding: 0 1rem;
    max-height: 0;
    overflow: hidden;
    transition: all 0.3s ease;
}

.faq-answer.active {
    padding: 1rem;
    max-height: 200px;
}

/* Catalog */
.catalog-header {
    padding: 2rem 0;
    background-color: var(--bg-secondary);
}

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

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

.filter-group label {
    font-weight: 500;
    color: var(--text-primary);
}

.filter-input {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 1rem;
    min-width: 200px;
}

.filter-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px hsla(297, 70%, 50%, 0.1);
}

.catalog-results {
    padding: 2rem 0;
}

.results-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.results-count {
    color: var(--text-secondary);
}

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

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-primary);
}

.form-input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 1rem;
    transition: border-color 0.2s ease;
}

.form-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px hsla(297, 70%, 50%, 0.1);
}

.form-input.error {
    border-color: #dc3545;
}

.form-error {
    color: #dc3545;
    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: 0.5rem;
    margin: 1rem 0;
}

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

.checkbox-group label {
    font-size: 0.875rem;
    line-height: 1.4;
}

/* Checkout */
.checkout-header {
    padding: 2rem 0;
    background-color: var(--bg-secondary);
    text-align: center;
}

.checkout-steps {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-top: 1rem;
}

.step {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    border-radius: var(--radius-md);
    background-color: var(--bg-tertiary);
    color: var(--text-secondary);
}

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

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

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

.checkout-form {
    background-color: var(--bg-secondary);
    padding: 2rem;
    border-radius: var(--radius-lg);
}

.order-summary {
    background-color: var(--bg-primary);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-lg);
    padding: 2rem;
    height: fit-content;
    box-shadow: var(--shadow-md);
}

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

.summary-item:last-child {
    border-bottom: none;
    font-weight: 600;
    font-size: 1.25rem;
    color: var(--primary-color);
}

.payment-methods {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin: 1rem 0;
    padding: 1rem;
    background-color: var(--bg-secondary);
    border-radius: var(--radius-md);
}

.payment-icon {
    width: 40px;
    height: 25px;
    background-color: var(--text-secondary);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 0.75rem;
    font-weight: bold;
}

/* Footer */
.footer {
    background-color: var(--secondary-color);
    color: white;
    padding: 3rem 0 1rem;
    margin-top: 4rem;
}

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

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

.footer-section ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

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

.footer-section a {
    color: hsl(210, 10%, 75%);
    transition: color 0.2s ease;
}

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

.footer-brand {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

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

.contact-info p {
    margin-bottom: 0.5rem;
    color: hsl(210, 10%, 75%);
}

.footer-bottom {
    border-top: 1px solid hsl(210, 15%, 35%);
    padding-top: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.footer-legal {
    display: flex;
    gap: 1rem;
}

.footer-legal a {
    color: hsl(210, 10%, 75%);
    font-size: 0.875rem;
}

.footer-bottom p {
    margin: 0;
    color: hsl(210, 10%, 75%);
    font-size: 0.875rem;
}

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

    .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-actions {
        justify-content: center;
    }

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

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

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

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

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

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

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

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

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

    .results-header {
        flex-direction: column;
        gap: 1rem;
        align-items: stretch;
    }

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

    h1 { font-size: 2rem; }
    h2 { font-size: 1.75rem; }
    h3 { font-size: 1.25rem; }
}

@media (max-width: 480px) {
    .container {
        padding: 0 0.75rem;
    }

    .hero {
        padding: 2rem 0;
    }

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

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

    .course-card {
        margin-bottom: 1rem;
    }

    .btn {
        padding: 0.625rem 1.25rem;
        font-size: 0.875rem;
    }

    .hero-actions {
        flex-direction: column;
        align-items: stretch;
    }
}

/* 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,
input:focus,
select:focus,
textarea:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}