* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bg-primary: #1a1b1e;
    --bg-secondary: #25262b;
    --bg-tertiary: #2c2e33;
    --text-primary: #c1c2c5;
    --text-secondary: #909296;
    --accent: #4dabf7;
    --accent-hover: #339af0;
    --border: #373a40;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

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

/* Navbar */
.navbar {
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo h1 {
    color: var(--accent);
    font-size: 1.5rem;
    font-weight: 600;
}

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

.nav-menu a {
    color: var(--text-primary);
    text-decoration: none;
    transition: color 0.3s;
    font-weight: 500;
}

.nav-menu a:hover,
.nav-menu a.active {
    color: var(--accent);
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
    padding: 5rem 0;
    text-align: center;
    border-bottom: 1px solid var(--border);
}

.hero h2 {
    font-size: 3rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

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

.btn-primary {
    display: inline-block;
    background-color: var(--accent);
    color: white;
    padding: 0.75rem 2rem;
    text-decoration: none;
    border-radius: 6px;
    font-weight: 600;
    transition: background-color 0.3s;
}

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

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

.features h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: var(--text-primary);
}

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

.feature-card {
    background-color: var(--bg-secondary);
    padding: 2rem;
    border-radius: 8px;
    border: 1px solid var(--border);
    text-align: center;
    transition: transform 0.3s, border-color 0.3s;
}

.feature-card:hover {
    transform: translateY(-5px);
    border-color: var(--accent);
}

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

.feature-card h3 {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

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

/* Popular Courses */
.popular-courses {
    padding: 4rem 0;
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border);
}

.popular-courses h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    color: var(--text-primary);
}

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

.course-card {
    background-color: var(--bg-tertiary);
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid var(--border);
    transition: transform 0.3s, border-color 0.3s;
}

.course-card:hover {
    transform: translateY(-5px);
    border-color: var(--accent);
}

.course-image {
    background: linear-gradient(135deg, var(--accent) 0%, var(--accent-hover) 100%);
    height: 150px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
    font-weight: 600;
}

.course-card h3 {
    padding: 1rem;
    color: var(--text-primary);
}

.course-card p {
    padding: 0 1rem;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.course-level {
    display: inline-block;
    background-color: var(--bg-secondary);
    color: var(--accent);
    padding: 0.25rem 0.75rem;
    border-radius: 4px;
    font-size: 0.875rem;
    margin: 0 1rem 1rem;
}

/* Content Pages */
.content-page {
    padding: 3rem 0;
    min-height: 60vh;
}

.content-page h1 {
    font-size: 2.5rem;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

.content-page h2 {
    font-size: 2rem;
    margin-top: 2rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.content-page p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
    line-height: 1.8;
}

.content-page ul, .content-page ol {
    margin-left: 2rem;
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

.content-page li {
    margin-bottom: 0.5rem;
}

/* Contact Form */
.contact-form {
    max-width: 600px;
    margin: 2rem auto;
}

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

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

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 6px;
    color: var(--text-primary);
    font-family: inherit;
    font-size: 1rem;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent);
}

.form-group textarea {
    resize: vertical;
    min-height: 150px;
}

/* Footer */
footer {
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border);
    padding: 2rem 0;
    margin-top: auto;
}

footer .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

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

.footer-links {
    display: flex;
    gap: 1.5rem;
}

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.3s;
}

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

/* Responsive */
@media (max-width: 768px) {
    .nav-menu {
        gap: 1rem;
    }
    
    .hero h2 {
        font-size: 2rem;
    }
    
    .features-grid,
    .courses-grid {
        grid-template-columns: 1fr;
    }
    
    footer .container {
        flex-direction: column;
        text-align: center;
    }
}