* {
    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(210, 50%, 50%);
    --accent-color: hsl(45, 90%, 55%);
    --text-primary: hsl(220, 15%, 20%);
    --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%, 95%);
    --border-color: hsl(220, 15%, 90%);
    --shadow-light: 0 2px 8px hsla(220, 15%, 20%, 0.08);
    --shadow-medium: 0 4px 16px hsla(220, 15%, 20%, 0.12);
    --shadow-heavy: 0 8px 32px hsla(220, 15%, 20%, 0.16);
    --radius-small: 6px;
    --radius-medium: 12px;
    --radius-large: 24px;
    --transition: all 0.3s ease;
}

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

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

/* Header */
.header {
    background: var(--bg-primary);
    box-shadow: var(--shadow-light);
    position: sticky;
    top: 0;
    z-index: 1000;
}

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

.nav-brand .logo {
    height: 40px;
    width: auto;
}

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

.nav-link {
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    transition: var(--transition);
    padding: 0.5rem 1rem;
    border-radius: var(--radius-small);
}

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

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

.nav-toggle span {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    margin: 3px 0;
    transition: var(--transition);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: var(--radius-medium);
    text-decoration: none;
    font-weight: 600;
    text-align: center;
    transition: var(--transition);
    border: 2px solid transparent;
    cursor: pointer;
    font-size: 1rem;
}

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

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-medium);
}

.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-primary);
    border-color: var(--border-color);
}

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

/* Hero Section */
.hero {
    padding: 80px 0;
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
    position: relative;
    overflow: hidden;
}

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

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    line-height: 1.6;
}

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

.hero-image {
    text-align: center;
}

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

/* Sections */
.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 3rem;
    color: var(--text-primary);
}

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

/* Features */
.features {
    padding: 80px 0;
    background: var(--bg-primary);
}

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

.feature-card {
    text-align: center;
    padding: 2rem;
    background: var(--bg-secondary);
    border-radius: var(--radius-large);
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-medium);
}

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

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

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

/* Courses */
.courses-featured {
    padding: 80px 0;
    background: var(--bg-secondary);
}

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

.course-card {
    background: var(--bg-primary);
    border-radius: var(--radius-large);
    overflow: hidden;
    box-shadow: var(--shadow-light);
    transition: var(--transition);
}

.course-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-heavy);
}

.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-small);
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.course-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

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

.course-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    font-size: 0.875rem;
    color: var(--text-light);
}

.course-price {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

/* Trust Indicators */
.trust-indicators {
    padding: 80px 0;
    background: var(--bg-primary);
}

.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;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

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

/* Course Detail */
.course-detail {
    padding: 40px 0;
}

.course-header {
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: 3rem;
    margin-bottom: 3rem;
}

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

.course-sidebar {
    background: var(--bg-secondary);
    padding: 2rem;
    border-radius: var(--radius-large);
    height: fit-content;
    position: sticky;
    top: 100px;
}

.course-sidebar img {
    width: 100%;
    border-radius: var(--radius-medium);
    margin-bottom: 1rem;
}

.course-sections {
    display: grid;
    gap: 2rem;
}

.course-section {
    background: var(--bg-secondary);
    padding: 2rem;
    border-radius: var(--radius-large);
}

.course-section h2 {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

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

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

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

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

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

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.form-input,
.form-select,
.form-textarea {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-medium);
    font-size: 1rem;
    transition: var(--transition);
    background: var(--bg-primary);
}

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

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

.form-error {
    color: hsl(0, 70%, 50%);
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

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

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

/* Checkout */
.checkout {
    padding: 40px 0;
}

.checkout-container {
    max-width: 800px;
    margin: 0 auto;
}

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

.step {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 1rem 2rem;
    background: var(--bg-secondary);
    border-radius: var(--radius-medium);
    margin: 0 0.5rem;
}

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

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

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

.order-summary {
    background: var(--bg-primary);
    padding: 2rem;
    border-radius: var(--radius-large);
    margin-bottom: 2rem;
    border: 2px solid var(--border-color);
}

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

.payment-icon {
    width: 40px;
    height: 24px;
}

/* Footer */
.footer {
    background: var(--text-primary);
    color: white;
    padding: 60px 0 20px;
}

.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;
}

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

.footer-section a {
    color: hsl(220, 15%, 80%);
    text-decoration: none;
    transition: var(--transition);
}

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

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid hsl(220, 15%, 30%);
    color: hsl(220, 15%, 70%);
}

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

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

    .nav-toggle {
        display: flex;
    }

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

    .hero-title {
        font-size: 2rem;
    }

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

    .course-sidebar {
        position: static;
    }

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

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

    .section-title {
        font-size: 2rem;
    }

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

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

    .hero {
        padding: 40px 0;
    }

    .hero-title {
        font-size: 1.75rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .features,
    .courses-featured,
    .trust-indicators {
        padding: 40px 0;
    }

    .section-title {
        font-size: 1.75rem;
        margin-bottom: 2rem;
    }

    .btn {
        padding: 10px 20px;
        font-size: 0.9rem;
    }
}

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