/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    line-height: 1.6;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    color: #333;
    background-color: #ffffff;
}

img {
    max-width: 100%;
    height: auto;
}

a {
    text-decoration: none;
    color: inherit;
}

button {
    border: none;
    background: none;
    cursor: pointer;
    font-family: inherit;
}

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

/* Header */
.header {
    background: #ffffff;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
    max-width: 1200px;
    margin: 0 auto;
    padding-left: 1rem;
    padding-right: 1rem;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 700;
    font-size: 1.25rem;
    color: #6366f1;
}

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

.nav-link {
    color: #64748b;
    font-weight: 500;
    transition: color 0.3s ease;
    padding: 0.5rem 0;
}

.nav-link:hover,
.nav-link.active {
    color: #6366f1;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
}

.nav-toggle span {
    width: 25px;
    height: 3px;
    background: #333;
    transition: 0.3s;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    font-weight: 600;
    text-align: center;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.btn-primary {
    background: #6366f1;
    color: white;
}

.btn-primary:hover {
    background: #5855eb;
    transform: translateY(-2px);
}

.btn-secondary {
    background: transparent;
    color: #6366f1;
    border-color: #6366f1;
}

.btn-secondary:hover {
    background: #6366f1;
    color: white;
}

.btn-outline {
    background: transparent;
    color: #6366f1;
    border-color: #e2e8f0;
}

.btn-outline:hover {
    border-color: #6366f1;
    background: #f8fafc;
}

/* Hero Section */
.hero {
    position: relative;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 4rem 0;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    top: 0;
    right: 0;
    width: 50%;
    height: 100%;
    opacity: 0.1;
    z-index: 1;
}

.hero-bg img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

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

.hero h1 {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.hero p {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

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

/* Features Section */
.features {
    padding: 4rem 0;
    background: #f8fafc;
}

.features h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: #1e293b;
}

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

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: 1rem;
    text-align: center;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

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

.feature-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: #1e293b;
}

.feature-card p {
    color: #64748b;
    line-height: 1.6;
}

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

.featured-courses h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: #1e293b;
}

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

.course-card {
    background: white;
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.course-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

.course-image {
    position: relative;
    height: 200px;
    overflow: hidden;
}

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

.course-level {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: #6366f1;
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 1rem;
    font-size: 0.875rem;
    font-weight: 600;
}

.course-content {
    padding: 1.5rem;
}

.course-content h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}

.course-content h3 a {
    color: #1e293b;
    transition: color 0.3s ease;
}

.course-content h3 a:hover {
    color: #6366f1;
}

.course-category {
    color: #6366f1;
    font-weight: 600;
    font-size: 0.875rem;
    margin-bottom: 0.75rem;
}

.course-description {
    color: #64748b;
    margin-bottom: 1rem;
    line-height: 1.6;
}

.course-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    font-size: 0.875rem;
}

.course-duration {
    color: #64748b;
}

.course-price {
    font-weight: 700;
    color: #059669;
    font-size: 1.125rem;
}

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

/* CTA Section */
.cta-section {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 4rem 0;
    text-align: center;
}

.cta-content h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.cta-content p {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.9;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* Search and Filter */
.search-filter {
    background: #f8fafc;
    padding: 2rem 0;
}

.search-form {
    display: flex;
    gap: 1rem;
    max-width: 800px;
    margin: 0 auto;
    flex-wrap: wrap;
}

.search-input,
.filter-select {
    flex: 1;
    min-width: 200px;
    padding: 0.75rem 1rem;
    border: 2px solid #e2e8f0;
    border-radius: 0.5rem;
    font-size: 1rem;
}

.search-input:focus,
.filter-select:focus {
    outline: none;
    border-color: #6366f1;
}

/* Course Detail */
.course-header {
    background: #f8fafc;
    padding: 2rem 0;
}

.course-title {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: #1e293b;
}

.course-meta-detail {
    display: flex;
    gap: 2rem;
    flex-wrap: wrap;
    margin-bottom: 1rem;
}

.course-meta-detail span {
    color: #64748b;
    font-weight: 500;
}

.course-price-detail {
    font-size: 2rem;
    font-weight: 700;
    color: #059669;
}

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

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

.course-main h2 {
    font-size: 1.75rem;
    margin-bottom: 1rem;
    color: #1e293b;
}

.course-main p {
    color: #64748b;
    line-height: 1.7;
    margin-bottom: 1.5rem;
}

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

.course-main li {
    padding: 0.5rem 0;
    color: #64748b;
    position: relative;
    padding-left: 1.5rem;
}

.course-main li::before {
    content: "✓";
    color: #059669;
    font-weight: bold;
    position: absolute;
    left: 0;
}

.course-sidebar {
    background: #f8fafc;
    padding: 2rem;
    border-radius: 1rem;
    height: fit-content;
}

.instructor-card {
    text-align: center;
    margin-bottom: 2rem;
}

.instructor-name {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: #1e293b;
}

.instructor-bio {
    color: #64748b;
    line-height: 1.6;
}

/* FAQ */
.faq-item {
    border-bottom: 1px solid #e2e8f0;
    margin-bottom: 1rem;
}

.faq-question {
    width: 100%;
    text-align: left;
    padding: 1rem 0;
    font-weight: 600;
    color: #1e293b;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.faq-question::after {
    content: "+";
    font-size: 1.5rem;
    color: #6366f1;
}

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

.faq-answer {
    padding-bottom: 1rem;
    color: #64748b;
    line-height: 1.6;
    display: none;
}

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

/* Contact Form */
.contact-form {
    background: #f8fafc;
    padding: 2rem;
    border-radius: 1rem;
    margin-bottom: 2rem;
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: #1e293b;
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 2px solid #e2e8f0;
    border-radius: 0.5rem;
    font-size: 1rem;
    font-family: inherit;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: #6366f1;
}

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

/* Footer */
.footer {
    background: #1e293b;
    color: #cbd5e1;
    padding: 3rem 0 1rem;
}

.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;
    color: white;
    margin-bottom: 1rem;
}

.footer-section h3 {
    color: white;
    margin-bottom: 1rem;
    font-size: 1.125rem;
}

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

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

.footer-section a {
    color: #cbd5e1;
    transition: color 0.3s ease;
}

.footer-section a:hover {
    color: #6366f1;
}

.footer-bottom {
    border-top: 1px solid #334155;
    padding-top: 1rem;
    text-align: center;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 1rem;
        box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
        gap: 0;
    }

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

    .nav-toggle {
        display: flex;
    }

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

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

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

    .features h2,
    .featured-courses h2 {
        font-size: 2rem;
    }

    .cta-content h2 {
        font-size: 2rem;
    }

    .cta-content p {
        font-size: 1rem;
    }

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

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

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

    .search-form {
        flex-direction: column;
    }

    .course-meta-detail {
        flex-direction: column;
        gap: 0.5rem;
    }
}

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

    .hero {
        padding: 2rem 0;
    }

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

    .features,
    .featured-courses {
        padding: 2rem 0;
    }

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

    .course-content {
        padding: 1rem;
    }
}

/* Accessibility */
.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 */
a:focus,
button:focus,
input:focus,
textarea:focus,
select:focus {
    outline: 2px solid #6366f1;
    outline-offset: 2px;
}

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