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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background: #f8f9fa;
}

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

/* Header */
.header {
    background: white;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: #2563eb;
}

.nav {
    display: flex;
    gap: 20px;
}

.nav a {
    text-decoration: none;
    color: #555;
    font-weight: 500;
    transition: color 0.3s;
}

.nav a:hover,
.nav a.active {
    color: #2563eb;
}

.auth-buttons {
    display: flex;
    gap: 10px;
}

.btn {
    padding: 10px 20px;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s;
    text-decoration: none;
    display: inline-block;
}

.btn-primary {
    background: #2563eb;
    color: white;
}

.btn-primary:hover {
    background: #1d4ed8;
}

.btn-outline {
    background: transparent;
    border: 2px solid #2563eb;
    color: #2563eb;
}

.btn-outline:hover {
    background: #2563eb;
    color: white;
}

.btn-lg {
    padding: 15px 30px;
    font-size: 1.1rem;
}

/* Hero */
.hero {
    padding: 80px 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.hero .container {
    display: flex;
    align-items: center;
    gap: 40px;
}

.hero-content {
    flex: 1;
}

.hero-content h1 {
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.hero-content p {
    font-size: 1.2rem;
    margin-bottom: 30px;
    opacity: 0.9;
}

.hero-buttons {
    display: flex;
    gap: 15px;
}

.hero-image {
    flex: 1;
    text-align: center;
}

.hero-icon {
    font-size: 8rem;
    animation: float 3s ease-in-out infinite;
}

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

/* Sections */
.section-title {
    text-align: center;
    font-size: 2rem;
    margin-bottom: 40px;
    color: #333;
}

.features {
    padding: 80px 0;
    background: white;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 30px;
}

.feature-card {
    background: #f8f9fa;
    padding: 30px;
    border-radius: 12px;
    text-align: center;
    transition: transform 0.3s, box-shadow 0.3s;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 15px;
}

.feature-card h3 {
    margin-bottom: 10px;
    color: #2563eb;
}

/* Stats */
.stats {
    padding: 60px 0;
    background: #2563eb;
    color: white;
}

.stats .container {
    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
    gap: 30px;
}

.stat-item {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 2.5rem;
    font-weight: 700;
}

.stat-label {
    font-size: 1rem;
    opacity: 0.8;
}

/* Testimonials */
.testimonials {
    padding: 80px 0;
    background: white;
}

.testimonial-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 30px;
}

.testimonial-card {
    background: #f8f9fa;
    padding: 25px;
    border-radius: 12px;
    border-left: 4px solid #2563eb;
}

.testimonial-author {
    display: block;
    margin-top: 15px;
    font-weight: 600;
    color: #2563eb;
}

/* Footer */
.footer {
    background: #333;
    color: white;
    text-align: center;
    padding: 40px 0;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.footer-links a {
    color: #ccc;
    text-decoration: none;
    transition: color 0.3s;
}

.footer-links a:hover {
    color: white;
}

/* Page Banner */
.page-banner {
    padding: 60px 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
}

.page-banner h1 {
    font-size: 2.2rem;
    margin-bottom: 10px;
}

/* About */
.about-content {
    padding: 80px 0;
    background: white;
}

.about-content .container {
    display: flex;
    gap: 40px;
    align-items: center;
}

.about-text {
    flex: 1;
}

.about-text h2 {
    color: #2563eb;
    margin: 20px 0 10px;
}

.about-text ul {
    list-style: disc;
    padding-left: 20px;
    margin-bottom: 20px;
}

.about-image {
    flex: 1;
    text-align: center;
}

.about-icon {
    font-size: 8rem;
}

/* Course Filters */
.course-filters {
    display: flex;
    gap: 15px;
    margin-bottom: 30px;
    justify-content: center;
}

.filter-btn {
    padding: 10px 20px;
    border: 2px solid #2563eb;
    background: transparent;
    color: #2563eb;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s;
}

.filter-btn.active,
.filter-btn:hover {
    background: #2563eb;
    color: white;
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 30px;
}

.course-card {
    background: white;
    border-radius: 12px;
    padding: 25px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    transition: transform 0.3s;
}

.course-card:hover {
    transform: translateY(-5px);
}

.course-card h3 {
    color: #2563eb;
    margin-bottom: 10px;
}

.course-card .course-level {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    margin-bottom: 10px;
}

.course-level.beginner { background: #d1fae5; color: #065f46; }
.course-level.intermediate { background: #fef3c7; color: #92400e; }
.course-level.advanced { background: #fce7f3; color: #9d174d; }

/* Quiz Section */
.quiz-section {
    padding: 60px 0;
    background: #f8f9fa;
    text-align: center;
}

.quiz-generator {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin: 20px 0;
    flex-wrap: wrap;
}

.quiz-select,
.input-field {
    padding: 12px 20px;
    border: 2px solid #ddd;
    border-radius: 8px;
    font-size: 1rem;
    width: 100%;
    max-width: 400px;
    transition: border-color 0.3s;
}

.quiz-select:focus,
.input-field:focus {
    border-color: #2563eb;
    outline: none;
}

.quiz-result {
    margin-top: 30px;
    text-align: left;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.quiz-question {
    background: white;
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 15px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

/* Forum */
.forum {
    padding: 60px 0;
    background: white;
}

.forum-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
}

.forum-posts {
    display: grid;
    gap: 20px;
}

.forum-post {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 12px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
}

.forum-post h3 {
    color: #2563eb;
    margin-bottom: 10px;
}

.forum-post .post-meta {
    font-size: 0.9rem;
    color: #666;
    margin-bottom: 10px;
}

.forum-new-post {
    margin-top: 30px;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 12px;
}

.forum-new-post h3 {
    margin-bottom: 15px;
}

/* Admin Panel */
.admin-panel {
    padding: 60px 0;
    background: white;
}

.admin-tabs {
    display: flex;
    gap: 10px;
    margin-bottom: 30px;
    flex-wrap: wrap;
    justify-content: center;
}

.tab-btn {
    padding: 12px 24px;
    border: none;
    background: #e5e7eb;
    color: #333;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s;
}

.tab-btn.active,
.tab-btn:hover {
    background: #2563eb;
    color: white;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.admin-form {
    display: flex;
    flex-direction: column;
    gap: 15px;
    max-width: 500px;
    margin-bottom: 30px;
}

.admin-list {
    display: grid;
    gap: 15px;
}

.admin-item {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 8px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 10px;
}

.admin-item .item-info h4 {
    color: #2563eb;
    margin-bottom: 5px;
}

.admin-item .item-actions {
    display: flex;
    gap: 10px;
}

/* Responsive */
@media (max-width: 768px) {
    .header .container {
        flex-direction: column;
        gap: 15px;
    }
    .nav {
        flex-wrap: wrap;
        justify-content: center;
    }
    .hero .container {
        flex-direction: column;
        text-align: center;
    }
    .hero-content h1 {
        font-size: 2rem;
    }
    .hero-buttons {
        justify-content: center;
    }
    .about-content .container {
        flex-direction: column;
    }
    .stats .container {
        flex-direction: column;
        align-items: center;
    }
    .forum-header {
        flex-direction: column;
        gap: 15px;
    }
}