* {
    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%);
    --text-color: hsl(220, 15%, 15%);
    --text-light: hsl(220, 10%, 50%);
    --border-color: hsl(220, 15%, 90%);
    --bg-light: hsl(220, 15%, 98%);
    --bg-white: #ffffff;
    --success-color: hsl(142, 71%, 45%);
    --error-color: hsl(0, 84%, 60%);
    --warning-color: hsl(45, 100%, 51%);
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
    --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: 1.875rem;
    --font-size-4xl: 2.25rem;
}

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

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

/* Header & Navigation */
.header {
    background: var(--bg-white);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem;
    min-height: 4rem;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    color: var(--text-color);
}

.nav-logo {
    width: 2rem;
    height: 2rem;
}

.nav-title {
    font-size: var(--font-size-lg);
    font-weight: 700;
    color: var(--primary-color);
}

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

.nav-link {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    padding: 0.5rem 0;
    border-bottom: 2px solid transparent;
    transition: all 0.2s ease;
}

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

.nav-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    gap: 0.25rem;
}

.nav-toggle span {
    width: 1.5rem;
    height: 2px;
    background: var(--text-color);
    transition: all 0.3s ease;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    font-size: var(--font-size-base);
    font-weight: 500;
    text-decoration: none;
    border-radius: var(--radius-md);
    border: 1px solid transparent;
    cursor: pointer;
    transition: all 0.2s ease;
    min-height: 2.75rem;
}

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

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

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

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

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

.btn-outline:hover {
    background: var(--bg-light);
}

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

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

.hero-title {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1.5rem;
    color: var(--text-color);
}

.hero-description {
    font-size: var(--font-size-lg);
    color: var(--text-light);
    margin-bottom: 2rem;
}

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

.hero-image {
    display: flex;
    justify-content: center;
}

.hero-bg {
    max-width: 100%;
    height: auto;
}

/* Sections */
.section-title {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    text-align: center;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.section-description {
    font-size: var(--font-size-lg);
    color: var(--text-light);
    text-align: center;
    margin-bottom: 3rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

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

/* Features */
.features {
    padding: 4rem 0;
    background: var(--bg-white);
}

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

.feature-card {
    background: var(--bg-white);
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    text-align: center;
    transition: all 0.2s ease;
}

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

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

.feature-title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.feature-description {
    color: var(--text-light);
}

/* Featured Courses */
.featured-courses {
    padding: 4rem 0;
    background: var(--bg-light);
}

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

.course-card {
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    overflow: hidden;
    transition: all 0.2s ease;
}

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

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

.course-content {
    padding: 1.5rem;
}

.course-category {
    display: inline-block;
    background: var(--primary-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-sm);
    font-size: var(--font-size-sm);
    font-weight: 500;
    margin-bottom: 1rem;
}

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

.course-title a {
    text-decoration: none;
    color: inherit;
}

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

.course-description {
    color: var(--text-light);
    margin-bottom: 1rem;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.course-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    font-size: var(--font-size-sm);
    color: var(--text-light);
}

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

.course-actions {
    display: flex;
    gap: 0.5rem;
}

/* Course Detail Page */
.course-detail {
    padding: 2rem 0;
}

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

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

.course-sidebar {
    background: var(--bg-white);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 2rem;
    position: sticky;
    top: 6rem;
}

.course-info-list {
    list-style: none;
    margin-bottom: 2rem;
}

.course-info-list li {
    display: flex;
    justify-content: space-between;
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

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

.instructor-card {
    background: var(--bg-light);
    padding: 1.5rem;
    border-radius: var(--radius-md);
    margin: 2rem 0;
}

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

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

/* Lists */
.content-list {
    list-style: none;
    margin: 1rem 0;
}

.content-list li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

.content-list li:before {
    content: "✓";
    color: var(--success-color);
    font-weight: bold;
    margin-right: 0.5rem;
}

.content-list li:last-child {
    border-bottom: none;
}

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

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

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

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(168, 85, 247, 0.1);
}

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

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

.form-error {
    color: var(--error-color);
    font-size: var(--font-size-sm);
    margin-top: 0.25rem;
}

.form-checkbox {
    display: flex;
    align-items: flex-start;
    gap: 0.5rem;
}

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

/* Search & Filter */
.search-filters {
    background: var(--bg-white);
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    margin-bottom: 2rem;
}

.search-row {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 1rem;
    align-items: end;
}

.search-input {
    position: relative;
}

.search-input input {
    padding-left: 2.5rem;
}

.search-input::before {
    content: "🔍";
    position: absolute;
    left: 0.75rem;
    top: 50%;
    transform: translateY(-50%);
    z-index: 1;
}

/* Checkout */
.checkout-steps {
    display: flex;
    justify-content: center;
    margin-bottom: 3rem;
}

.step {
    display: flex;
    align-items: center;
    padding: 0.5rem 1rem;
    background: var(--bg-light);
    border-radius: var(--radius-md);
    margin: 0 0.5rem;
    font-weight: 500;
}

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

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

.checkout-summary {
    background: var(--bg-light);
    padding: 2rem;
    border-radius: var(--radius-lg);
    height: fit-content;
    position: sticky;
    top: 6rem;
}

.summary-item {
    display: flex;
    justify-content: space-between;
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

.summary-total {
    font-weight: 700;
    font-size: var(--font-size-lg);
    color: var(--text-color);
    border-bottom: none;
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 2px solid var(--border-color);
}

.payment-icons {
    display: flex;
    gap: 0.5rem;
    margin: 1rem 0;
}

.payment-icon {
    width: 40px;
    height: 24px;
    background: var(--border-color);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-xs);
}

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

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

.footer-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--primary-light);
}

.footer-heading {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: 1rem;
}

.footer-description {
    color: rgba(255, 255, 255, 0.8);
    line-height: 1.6;
}

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

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

.footer-links a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: color 0.2s ease;
}

.footer-links a:hover {
    color: var(--primary-light);
}

.footer-contact p {
    margin-bottom: 0.5rem;
    color: rgba(255, 255, 255, 0.8);
}

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

.footer-contact a:hover {
    color: var(--primary-light);
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.6);
}

/* FAQ */
.faq-item {
    background: var(--bg-white);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    margin-bottom: 1rem;
    overflow: hidden;
}

.faq-question {
    width: 100%;
    padding: 1.5rem;
    background: none;
    border: none;
    text-align: left;
    font-size: var(--font-size-lg);
    font-weight: 600;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

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

.faq-answer {
    padding: 0 1.5rem 1.5rem;
    color: var(--text-light);
    display: none;
}

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

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

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

    .course-sidebar {
        position: static;
    }

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

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

    .checkout-summary {
        position: static;
        order: -1;
    }

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

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

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

    .btn {
        width: 100%;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 0.5rem;
    }

    .hero {
        padding: 2rem 0;
    }

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

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

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

    .course-card {
        margin: 0 0.5rem;
    }
}

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

button:focus,
.btn:focus {
    outline-offset: 4px;
}