* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background: #f8f9fa;
    color: #333;
    line-height: 1.6;
}

/* Navigation */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #fff;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.logo a {
    color: #fff;
    text-decoration: none;
    font-size: 1.5rem;
    font-weight: bold;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 1.5rem;
}

.nav-links a {
    color: #fff;
    text-decoration: none;
    transition: opacity 0.3s;
}

.nav-links a:hover {
    opacity: 0.8;
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: #fff;
    margin: 3px 0;
    transition: 0.3s;
}

/* Hero */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #fff;
    text-align: center;
    padding: 4rem 2rem;
}

.hero-content h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.hero-content p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
}

.btn-primary {
    display: inline-block;
    background: #fff;
    color: #667eea;
    padding: 0.8rem 2rem;
    border-radius: 30px;
    text-decoration: none;
    font-weight: bold;
    transition: transform 0.3s, box-shadow 0.3s;
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.2);
}

/* Sections */
.section {
    padding: 3rem 2rem;
    max-width: 1200px;
    margin: auto;
}

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

/* Search & Filter */
.search-filter {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.search-filter input,
.search-filter select {
    padding: 0.5rem 1rem;
    border: 1px solid #ddd;
    border-radius: 25px;
    font-size: 1rem;
    outline: none;
    transition: border 0.3s;
}

.search-filter input:focus,
.search-filter select:focus {
    border-color: #667eea;
}

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

.card {
    background: #fff;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0,0,0,0.15);
}

.card-img {
    height: 150px;
}

.card-body {
    padding: 1.5rem;
}

.card-body h3 {
    margin-bottom: 0.5rem;
}

.card-body p {
    margin-bottom: 0.5rem;
    color: #666;
}

.rating {
    margin: 0.5rem 0;
}

.btn-secondary {
    display: inline-block;
    background: #667eea;
    color: #fff;
    padding: 0.5rem 1.5rem;
    border-radius: 25px;
    text-decoration: none;
    transition: background 0.3s;
}

.btn-secondary:hover {
    background: #764ba2;
}

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

.teacher-card {
    background: #fff;
    border-radius: 15px;
    padding: 2rem;
    text-align: center;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    transition: transform 0.3s;
}

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

.teacher-avatar {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: #fff;
    margin: 0 auto 1rem;
}

.teacher-title {
    color: #667eea;
    font-weight: bold;
}

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

.review-card {
    background: #fff;
    border-radius: 15px;
    padding: 1.5rem;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

/* Footer */
footer {
    background: #333;
    color: #fff;
    text-align: center;
    padding: 1.5rem;
    margin-top: 2rem;
}

.footer-links a {
    color: #fff;
    text-decoration: none;
    margin: 0 0.5rem;
}

.footer-links a:hover {
    text-decoration: underline;
}

/* Login */
.login-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: linear-gradient(135deg, #667eea, #764ba2);
}

.login-form {
    background: #fff;
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
    width: 350px;
}

.login-form h2 {
    margin-bottom: 1.5rem;
    text-align: center;
}

.login-form input {
    width: 100%;
    padding: 0.8rem;
    margin-bottom: 1rem;
    border: 1px solid #ddd;
    border-radius: 8px;
}

.login-form button {
    width: 100%;
    padding: 0.8rem;
    background: #667eea;
    color: #fff;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
}

.login-form button:hover {
    background: #764ba2;
}

.error {
    color: red;
    text-align: center;
    margin-bottom: 1rem;
}

.success {
    color: green;
    text-align: center;
    margin-bottom: 1rem;
}

/* Admin */
.admin-container {
    max-width: 800px;
    margin: 2rem auto;
    padding: 2rem;
    background: #fff;
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

.admin-container fieldset {
    border: 1px solid #ddd;
    border-radius: 8px;
    padding: 1rem;
    margin-bottom: 1rem;
}

.admin-container input {
    width: 100%;
    padding: 0.5rem;
    margin-bottom: 0.5rem;
    border: 1px solid #ddd;
    border-radius: 5px;
}

.admin-container button {
    padding: 0.8rem 2rem;
    background: #667eea;
    color: #fff;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    font-size: 1rem;
}

/* Page styles */
.page-content {
    max-width: 800px;
    margin: 2rem auto;
    padding: 2rem;
    background: #fff;
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

/* Responsive */
@media (max-width: 768px) {
    .nav-links {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 60px;
        left: 0;
        width: 100%;
        background: #667eea;
        padding: 1rem;
    }

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

    .hamburger {
        display: flex;
    }

    .hero-content h1 {
        font-size: 1.8rem;
    }

    .search-filter {
        flex-direction: column;
        align-items: center;
    }
}