* {
    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%, 25%);
    --text-light: hsl(220, 10%, 50%);
    --bg-color: hsl(0, 0%, 100%);
    --bg-light: hsl(220, 20%, 98%);
    --bg-section: hsl(220, 20%, 96%);
    --border-color: hsl(220, 20%, 90%);
    --shadow: 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 0.3s ease;
}

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-color);
}

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

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

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 0;
}

.nav__logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    color: var(--text-color);
    font-weight: 700;
    font-size: 1.25rem;
}

.nav__menu {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.nav__link {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

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

.nav__link--active::after {
    content: '';
    position: absolute;
    bottom: -0.5rem;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--primary-color);
}

.nav__toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.nav__toggle span {
    width: 24px;
    height: 2px;
    background: var(--text-color);
    transition: var(--transition);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    border-radius: var(--border-radius);
    transition: var(--transition);
    border: 2px solid transparent;
    cursor: pointer;
    min-height: 48px;
}

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

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

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

.btn--secondary:hover {
    background: var(--bg-light);
    border-color: var(--primary-color);
    color: var(--primary-color);
}

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

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

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

.hero__bg {
    position: absolute;
    top: 0;
    right: -10%;
    width: 50%;
    height: 100%;
    background: url('/assets/bg-pattern-01.svg') no-repeat center;
    background-size: contain;
    opacity: 0.1;
}

.hero__content {
    max-width: 600px;
    position: relative;
    z-index: 2;
}

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

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

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

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

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

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

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

.feature__icon {
    margin-bottom: 1.5rem;
}

.feature__title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.feature__description {
    color: var(--text-light);
    line-height: 1.6;
}

/* Sections */
.section__header {
    text-align: center;
    margin-bottom: 3rem;
}

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

.section__description {
    font-size: 1.25rem;
    color: var(--text-light);
    max-width: 600px;
    margin: 0 auto;
}

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

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

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

.course-card {
    background: var(--bg-color);
    border-radius: var(--border-radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
    text-decoration: none;
    color: inherit;
}

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

.course-card__image {
    width: 100%;
    height: 200px;
    object-fit: cover;
    background: var(--bg-section);
}

.course-card__content {
    padding: 1.5rem;
}

.course-card__header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1rem;
}

.course-card__category {
    background: var(--primary-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 1rem;
    font-size: 0.875rem;
    font-weight: 600;
}

.course-card__difficulty {
    font-size: 0.875rem;
    color: var(--text-light);
    background: var(--bg-light);
    padding: 0.25rem 0.75rem;
    border-radius: 1rem;
}

.course-card__title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--text-color);
    line-height: 1.3;
}

.course-card__description {
    color: var(--text-light);
    margin-bottom: 1rem;
    line-height: 1.5;
}

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

.course-card__price {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary-color);
}

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

.course-hero {
    background: var(--bg-section);
    padding: 3rem 0;
    margin-bottom: 3rem;
}

.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-color);
}

.course-hero__meta {
    display: flex;
    gap: 1rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.course-hero__meta span {
    background: var(--bg-color);
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius);
    font-size: 0.875rem;
    font-weight: 600;
}

.course-hero__description {
    font-size: 1.125rem;
    color: var(--text-light);
    line-height: 1.6;
    margin-bottom: 2rem;
}

.course-hero__sidebar {
    background: var(--bg-color);
    padding: 2rem;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow);
    position: sticky;
    top: 6rem;
}

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

.course-info {
    margin: 2rem 0;
}

.course-info__item {
    display: flex;
    justify-content: space-between;
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--border-color);
}

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

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

.course-main {
    background: var(--bg-color);
    padding: 2rem;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow);
}

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

.course-section h2 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    color: var(--text-color);
}

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

.course-section li {
    padding: 0.5rem 0;
    position: relative;
    padding-left: 1.5rem;
}

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

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

.curriculum-item h4 {
    font-weight: 600;
    margin-bottom: 0.5rem;
}

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

.instructor-card h3 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.faq-item {
    background: var(--bg-light);
    padding: 1.5rem;
    margin-bottom: 1rem;
    border-radius: var(--border-radius);
}

.faq-item h4 {
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

/* Forms */
.form {
    max-width: 600px;
    margin: 0 auto;
}

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

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

.form-input,
.form-select,
.form-textarea {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
    background: var(--bg-color);
}

.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-error {
    color: #ef4444;
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

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

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

/* Checkout */
.checkout {
    padding: 2rem 0;
}

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

.checkout-step {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background: var(--bg-light);
    color: var(--text-light);
    border-radius: var(--border-radius);
    margin: 0 0.5rem;
}

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

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

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

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

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

.summary-total {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary-color);
}

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

.payment-icon {
    width: 40px;
    height: 24px;
    background: var(--bg-color);
    border-radius: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow);
}

/* Footer */
.footer {
    background: 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__logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 700;
    font-size: 1.25rem;
    margin-bottom: 1rem;
}

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

.footer__title {
    font-size: 1.125rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.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: var(--transition);
}

.footer__links a:hover {
    color: white;
}

.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: white;
}

.footer__bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.2);
    color: rgba(255, 255, 255, 0.6);
}

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

    .nav__menu--active {
        display: flex;
    }

    .nav__toggle {
        display: flex;
    }

    .hero__title {
        font-size: 2rem;
    }

    .hero__description {
        font-size: 1rem;
    }

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

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

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

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

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

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

    .section__title {
        font-size: 2rem;
    }

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

    .feature {
        padding: 1.5rem;
    }
}

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

    .hero {
        padding: 2rem 0;
    }

    .hero__title {
        font-size: 1.75rem;
    }

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

    .course-card__content {
        padding: 1rem;
    }

    .checkout-form,
    .course-main,
    .course-hero__sidebar {
        padding: 1.5rem;
    }
}

/* Utility Classes */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }
.mb-1 { margin-bottom: 0.25rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-3 { margin-bottom: 1rem; }
.mb-4 { margin-bottom: 1.5rem; }
.mt-1 { margin-top: 0.25rem; }
.mt-2 { margin-top: 0.5rem; }
.mt-3 { margin-top: 1rem; }
.mt-4 { margin-top: 1.5rem; }

/* 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;
}