* {
    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-dark: hsl(220, 15%, 15%);
    --text-medium: hsl(220, 10%, 45%);
    --text-light: hsl(220, 5%, 65%);
    --background: hsl(0, 0%, 100%);
    --background-light: hsl(220, 20%, 98%);
    --background-medium: hsl(220, 15%, 95%);
    --border-light: hsl(220, 10%, 90%);
    --border-medium: hsl(220, 10%, 80%);
    --success: hsl(142, 71%, 45%);
    --warning: hsl(38, 92%, 50%);
    --error: hsl(0, 84%, 60%);
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --border-radius: 8px;
    --border-radius-lg: 12px;
    --transition: all 0.2s ease;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background: var(--background);
}

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

/* Header Styles */
.header {
    background: var(--background);
    border-bottom: 1px solid var(--border-light);
    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;
    gap: 12px;
    text-decoration: none;
    color: var(--text-dark);
    font-weight: 700;
    font-size: 1.2rem;
}

.nav ul {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
}

.nav a {
    text-decoration: none;
    color: var(--text-medium);
    font-weight: 500;
    transition: var(--transition);
}

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

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.mobile-menu-toggle span {
    width: 24px;
    height: 3px;
    background: var(--text-dark);
    margin: 2px 0;
    transition: var(--transition);
}

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

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-text h1 {
    font-size: 3rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 1.5rem;
    color: var(--text-dark);
}

.hero-text p {
    font-size: 1.2rem;
    color: var(--text-medium);
    margin-bottom: 2rem;
}

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

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

/* Button Styles */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 24px;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
    transition: var(--transition);
    cursor: pointer;
    border: none;
    min-height: 48px;
}

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

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

.btn-secondary {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

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

.btn-outline {
    background: transparent;
    color: var(--text-medium);
    border: 1px solid var(--border-medium);
}

.btn-outline:hover {
    background: var(--background-medium);
    color: var(--text-dark);
}

/* Features Section */
.features {
    padding: 5rem 0;
    background: var(--background);
}

.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-header h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text-dark);
}

.section-header p {
    font-size: 1.2rem;
    color: var(--text-medium);
    max-width: 600px;
    margin: 0 auto;
}

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

.feature-card {
    background: var(--background);
    padding: 2rem;
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--border-light);
    text-align: center;
    transition: var(--transition);
}

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

.feature-icon {
    margin-bottom: 1.5rem;
    display: flex;
    justify-content: center;
}

.feature-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-dark);
}

.feature-card p {
    color: var(--text-medium);
    line-height: 1.7;
}

/* Featured Courses Section */
.featured-courses {
    padding: 5rem 0;
    background: var(--background-light);
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.course-card {
    background: var(--background);
    border-radius: var(--border-radius-lg);
    overflow: hidden;
    border: 1px solid var(--border-light);
    transition: var(--transition);
    text-decoration: none;
    color: inherit;
    display: block;
}

.course-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    text-decoration: none;
    color: inherit;
}

.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;
    font-size: 0.9rem;
    color: var(--text-medium);
}

.course-category {
    background: var(--primary-color);
    color: white;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
}

.course-title {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-dark);
    line-height: 1.4;
}

.course-description {
    color: var(--text-medium);
    margin-bottom: 1rem;
    line-height: 1.6;
}

.course-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border-light);
}

.course-price {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.course-instructor {
    font-size: 0.9rem;
    color: var(--text-medium);
}

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

/* Course Detail Styles */
.course-hero {
    background: var(--background-light);
    padding: 3rem 0;
}

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

.course-hero-info h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text-dark);
}

.course-hero-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 2rem;
    margin: 1.5rem 0;
    padding: 1.5rem 0;
    border-top: 1px solid var(--border-light);
    border-bottom: 1px solid var(--border-light);
}

.meta-item {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.meta-label {
    font-size: 0.9rem;
    color: var(--text-medium);
    font-weight: 500;
}

.meta-value {
    font-weight: 600;
    color: var(--text-dark);
}

.course-sidebar {
    background: var(--background);
    padding: 2rem;
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--border-light);
    height: fit-content;
    position: sticky;
    top: 100px;
}

.course-sidebar img {
    width: 100%;
    border-radius: var(--border-radius);
    margin-bottom: 1.5rem;
}

.sidebar-price {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
}

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

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

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

.detail-section h2 {
    font-size: 1.8rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: var(--text-dark);
}

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

.detail-section li {
    padding: 0.5rem 0;
    padding-left: 1.5rem;
    position: relative;
    color: var(--text-medium);
}

.detail-section li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--success);
    font-weight: bold;
}

.curriculum-item {
    background: var(--background-light);
    padding: 1rem 1.5rem;
    border-radius: var(--border-radius);
    margin-bottom: 0.5rem;
    border-left: 4px solid var(--primary-color);
}

.curriculum-title {
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 0.25rem;
}

.curriculum-description {
    font-size: 0.9rem;
    color: var(--text-medium);
}

.instructor-section {
    background: var(--background-light);
    padding: 2rem;
    border-radius: var(--border-radius-lg);
}

.instructor-name {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 1rem;
}

.faq-item {
    border-bottom: 1px solid var(--border-light);
    padding: 1.5rem 0;
}

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

.faq-question {
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 0.5rem;
    font-size: 1.1rem;
}

.faq-answer {
    color: var(--text-medium);
    line-height: 1.6;
}

/* Courses Page */
.courses-header {
    background: var(--background-light);
    padding: 3rem 0;
    text-align: center;
}

.courses-filters {
    background: var(--background);
    padding: 2rem 0;
    border-bottom: 1px solid var(--border-light);
}

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

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

.filter-group label {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-medium);
}

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

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

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

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

.step {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-weight: 500;
}

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

.step.inactive {
    background: var(--background-medium);
    color: var(--text-medium);
}

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

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

.form-section {
    background: var(--background);
    padding: 2rem;
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--border-light);
}

.form-section h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: var(--text-dark);
}

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

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

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-medium);
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(189, 66, 187, 0.1);
}

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

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

.order-summary h3 {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: var(--text-dark);
}

.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: 1.1rem;
}

.payment-methods {
    display: flex;
    gap: 0.5rem;
    margin: 1rem 0;
    align-items: center;
}

.payment-icon {
    width: 40px;
    height: 24px;
    background: var(--background-medium);
    border-radius: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.7rem;
    font-weight: bold;
    color: var(--text-medium);
}

.security-note {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    color: var(--text-medium);
    margin: 1rem 0;
}

.checkbox-group {
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    margin: 1.5rem 0;
}

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

.checkbox-group label {
    margin-bottom: 0;
    line-height: 1.5;
}

.error-message {
    color: var(--error);
    font-size: 0.9rem;
    margin-top: 0.5rem;
}

.success-message {
    color: var(--success);
    font-size: 0.9rem;
    margin-top: 0.5rem;
}

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

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1.5fr;
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h4 {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: white;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 1rem;
    font-weight: 700;
    font-size: 1.2rem;
}

.footer-section p {
    color: rgba(255, 255, 255, 0.8);
    line-height: 1.6;
    margin-bottom: 1rem;
}

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

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

.footer-section ul li a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: var(--transition);
}

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

.contact-info p {
    margin-bottom: 0.5rem;
}

.contact-info a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: var(--transition);
}

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

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 1rem;
    text-align: center;
}

.footer-bottom p {
    color: rgba(255, 255, 255, 0.6);
    margin: 0;
}

/* Responsive Design */
@media (max-width: 768px) {
    .mobile-menu-toggle {
        display: flex;
    }

    .nav {
        display: none;
    }

    .hero-content {
        grid-template-columns: 1fr;
        gap: 2rem;
        text-align: center;
    }

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

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

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

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

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

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

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

    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

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

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

    .filter-group select,
    .filter-group input {
        min-width: auto;
    }
}

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

    .hero {
        padding: 2rem 0;
    }

    .features {
        padding: 3rem 0;
    }

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

    .section-header h2 {
        font-size: 2rem;
    }

    .course-card {
        margin: 0 -5px;
    }

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

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

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

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

.skeleton {
    background: linear-gradient(90deg, var(--background-medium) 25%, var(--background-light) 50%, var(--background-medium) 75%);
    background-size: 200% 100%;
    animation: loading 1.5s infinite;
}

@keyframes loading {
    0% {
        background-position: 200% 0;
    }
    100% {
        background-position: -200% 0;
    }
}