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

:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #8b5cf6;
    --accent-color: #06b6d4;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-dark: #111827;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1);
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --gradient-accent: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* Navbar */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: all 0.3s ease;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

.nav-brand i {
    font-size: 1.8rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

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

.nav-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    border-radius: 8px;
    transition: all 0.3s ease;
    position: relative;
}

.nav-link:hover {
    color: var(--primary-color);
    background-color: rgba(99, 102, 241, 0.1);
}

.nav-link.active {
    color: var(--primary-color);
    background-color: rgba(99, 102, 241, 0.1);
}

.nav-link.external::after {
    content: '↗';
    font-size: 0.8rem;
    opacity: 0.7;
}

/* Main Content */
.main-content {
    margin-top: 70px;
    min-height: calc(100vh - 140px);
}

/* Hero Section */
.hero {
    position: relative;
    min-height: 90vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    overflow: hidden;
}

.hero-shapes {
    position: absolute;
    width: 100%;
    height: 100%;
}

.shape {
    position: absolute;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.1);
    animation: float 6s ease-in-out infinite;
}

.shape-1 {
    width: 300px;
    height: 300px;
    top: 10%;
    left: 10%;
    animation-delay: 0s;
}

.shape-2 {
    width: 200px;
    height: 200px;
    top: 60%;
    right: 10%;
    animation-delay: 2s;
}

.shape-3 {
    width: 150px;
    height: 150px;
    bottom: 20%;
    left: 60%;
    animation-delay: 4s;
}

@keyframes float {
    0%, 100% { transform: translateY(0px) rotate(0deg); }
    50% { transform: translateY(-20px) rotate(180deg); }
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    max-width: 800px;
    padding: 0 2rem;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    color: white;
    margin-bottom: 1.5rem;
    line-height: 1.2;
    animation: fadeInUp 1s ease-out;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 2.5rem;
    line-height: 1.6;
    animation: fadeInUp 1s ease-out 0.2s both;
}

.cta-button {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 1rem 2rem;
    background: white;
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    font-size: 1.1rem;
    border-radius: 12px;
    box-shadow: var(--shadow-lg);
    transition: all 0.3s ease;
    animation: fadeInUp 1s ease-out 0.4s both;
}

.cta-button:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
    background: var(--bg-secondary);
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.feature-card {
    background: white;
    padding: 2.5rem;
    border-radius: 16px;
    box-shadow: var(--shadow-md);
    text-align: center;
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.feature-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 1.5rem;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: white;
}

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

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

/* How It Works Section */
.how-it-works {
    padding: 5rem 0;
    background: white;
}

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

.steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.step {
    text-align: center;
    padding: 2rem;
}

.step-number {
    width: 60px;
    height: 60px;
    margin: 0 auto 1.5rem;
    background: var(--gradient-accent);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
}

.step h4 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.step p {
    color: var(--text-secondary);
}

/* Recommend Page Styles */
.recommend-hero {
    padding: 3rem 0;
    background: var(--bg-secondary);
    text-align: center;
}

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

.page-subtitle {
    font-size: 1.1rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* Search Section */
.search-section {
    padding: 3rem 0;
    background: white;
}

.search-form {
    max-width: 800px;
    margin: 0 auto;
}

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

.input-label {
    display: block;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    font-size: 1.1rem;
}

.input-wrapper {
    display: flex;
    gap: 1rem;
    align-items: stretch;
}

.search-input {
    flex: 1;
    padding: 1rem 1.5rem;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    font-size: 1rem;
    transition: all 0.3s ease;
    background: white;
}

.search-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.search-button {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 1rem 2rem;
    background: var(--gradient-primary);
    color: white;
    border: none;
    border-radius: 12px;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.search-button:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

/* Results Section */
.results-section {
    padding: 3rem 0;
    background: var(--bg-secondary);
}

.results-header {
    text-align: center;
    margin-bottom: 3rem;
}

.results-header h2 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.results-header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

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

.course-card {
    background: white;
    border-radius: 16px;
    box-shadow: var(--shadow-md);
    overflow: hidden;
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
}

.course-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.course-header {
    padding: 1.5rem 1.5rem 1rem;
}

.course-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    line-height: 1.4;
    margin-bottom: 0.5rem;
}

.course-body {
    padding: 0 1.5rem 1rem;
    flex: 1;
}

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

.course-meta {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.platform-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.25rem 0.75rem;
    background: rgba(99, 102, 241, 0.1);
    color: var(--primary-color);
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 500;
}

.course-footer {
    padding: 1rem 1.5rem 1.5rem;
    border-top: 1px solid var(--border-color);
}

.course-button {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background: var(--gradient-primary);
    color: white;
    text-decoration: none;
    border-radius: 8px;
    font-weight: 500;
    transition: all 0.3s ease;
    width: 100%;
    justify-content: center;
}

.course-button:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

/* Error and Empty States */
.error-section, .empty-state {
    padding: 3rem 0;
    background: white;
}

.error-message, .empty-content {
    text-align: center;
    max-width: 500px;
    margin: 0 auto;
    padding: 2rem;
    border-radius: 12px;
    background: var(--bg-secondary);
}

.error-message {
    border-left: 4px solid #ef4444;
    background: #fef2f2;
}

.error-message i {
    color: #ef4444;
    font-size: 2rem;
    margin-bottom: 1rem;
}

.empty-content i {
    color: var(--text-light);
    font-size: 3rem;
    margin-bottom: 1rem;
}

.empty-content h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.empty-content p, .error-message p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Footer */
.footer {
    background: var(--bg-dark);
    color: white;
    padding: 2rem 0;
    text-align: center;
}

.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.footer p {
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.9rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-container {
        padding: 0 1rem;
    }
    
    .nav-menu {
        gap: 1rem;
    }
    
    .nav-link {
        padding: 0.5rem;
        font-size: 0.9rem;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.1rem;
    }
    
    .container {
        padding: 0 1rem;
    }
    
    .input-wrapper {
        flex-direction: column;
    }
    
    .search-button {
        justify-content: center;
    }
    
    .courses-grid {
        grid-template-columns: 1fr;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .steps {
        grid-template-columns: 1fr;
    }
}

/* Additional Mobile Optimizations */
@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .page-title {
        font-size: 2rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .feature-card, .step {
        padding: 1.5rem;
    }
    
    .nav-brand {
        font-size: 1.25rem;
    }
    
    .nav-link {
        font-size: 0.85rem;
        padding: 0.4rem 0.8rem;
    }
    
    .hero {
        min-height: 70vh;
        padding: 2rem 0;
    }
    
    .cta-button {
        padding: 0.875rem 1.5rem;
        font-size: 1rem;
    }
}

/* Loading States */
.loading {
    opacity: 0.7;
    pointer-events: none;
}

.loading .search-button {
    background: var(--text-light);
}

/* Accessibility Improvements */
.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 for better accessibility */
.nav-link:focus,
.cta-button:focus,
.search-button:focus,
.course-button:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --text-primary: #000000;
        --text-secondary: #333333;
        --border-color: #666666;
    }
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    .shape {
        animation: none;
    }
}

/* Print styles */
@media print {
    .navbar,
    .footer,
    .search-section {
        display: none;
    }
    
    .hero {
        background: white;
        color: black;
        min-height: auto;
        padding: 2rem 0;
    }
    
    .course-card {
        break-inside: avoid;
        box-shadow: none;
        border: 1px solid #ccc;
    }
}