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

:root {
    --primary: #6c5ce7;
    --primary-light: #a29bfe;
    --primary-dark: #5649c0;
    --secondary: #00cec9;
    --accent: #fd79a8;
    --success: #00b894;
    --warning: #fdcb6e;
    --danger: #d63031;
    --light: #f8f9fa;
    --dark: #2d3436;
    --gray: #636e72;
    --light-gray: #dfe6e9;
    --shadow: 0 4px 20px rgba(0,0,0,0.1);
    --shadow-sm: 0 2px 10px rgba(0,0,0,0.05);
    --radius: 12px;
    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
}

body {
    font-family: 'Inter', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: #333;
    line-height: 1.6;
}

/* Navigation */
.navbar {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(15px);
    padding: 1rem 0;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow-sm);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 2rem;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--primary);
    font-size: 1.5rem;
    font-weight: 800;
    text-decoration: none;
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-link {
    color: var(--dark);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary);
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--primary);
    border-radius: 1px;
}

/* Main Content */
.main-content {
    margin-top: 80px;
    padding: 2rem;
    max-width: 1400px;
    margin-left: auto;
    margin-right: auto;
}

.hero-section {
    text-align: center;
    margin-bottom: 3rem;
    color: white;
    padding: 2rem 0;
}

.hero-section h1 {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 1rem;
    background: linear-gradient(45deg, #fff, #f1f2f6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-section p {
    font-size: 1.2rem;
    opacity: 0.95;
    max-width: 800px;
    margin: 0 auto 2rem;
    line-height: 1.7;
}

/* AdSense Container */
.ad-container {
    margin: 2rem auto;
    max-width: 728px;
    text-align: center;
}

.ad-sidebar {
    position: sticky;
    top: 100px;
    width: 300px;
    margin-left: 2rem;
}

/* Class Sections */
.class-section {
    margin-bottom: 4rem;
}

.class-title {
    color: white;
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 2rem;
    display: flex;
    align-items: center;
    gap: 1rem;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.class-icon {
    width: 50px;
    height: 50px;
    border-radius: 15px;
    background: rgba(255, 255, 255, 0.2);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    backdrop-filter: blur(10px);
}

/* Subjects Grid */
.subjects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
}

.subject-card {
    background: rgba(255, 255, 255, 0.98);
    border-radius: 20px;
    padding: 2rem;
    box-shadow: var(--shadow);
    transition: var(--transition);
    cursor: pointer;
    position: relative;
    overflow: hidden;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.subject-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 5px;
    background: linear-gradient(45deg, var(--primary), var(--primary-dark));
}

.subject-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.subject-header {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    margin-bottom: 1.5rem;
}

.subject-icon {
    width: 60px;
    height: 60px;
    border-radius: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: white;
    background: var(--primary);
}

.subject-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--dark);
}

.subject-description {
    color: var(--gray);
    font-size: 1rem;
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.subject-stats {
    display: flex;
    gap: 1.5rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.stat-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    color: var(--gray);
    font-weight: 500;
}

.stat-item i {
    color: var(--primary);
}

.subject-actions {
    display: flex;
    justify-content: center;
}

.btn {
    padding: 1rem 2rem;
    border: none;
    border-radius: var(--radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    width: 100%;
    justify-content: center;
}

.btn-primary {
    background: linear-gradient(45deg, var(--primary), var(--primary-dark));
    color: white;
}

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

/* Footer */
.footer {
    background: var(--dark);
    color: white;
    margin-top: 4rem;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 3rem 2rem 2rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.footer-section h3,
.footer-section h4 {
    margin-bottom: 1rem;
    color: var(--primary-light);
}

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

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

.footer-section a {
    color: #ccc;
    text-decoration: none;
    transition: var(--transition);
}

.footer-section a:hover {
    color: var(--primary-light);
}

.social-links {
    display: flex;
    gap: 1rem;
}

.social-links a {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--primary);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.social-links a:hover {
    background: var(--primary-light);
    transform: translateY(-2px);
}

.footer-bottom {
    text-align: center;
    padding: 1rem 2rem;
    border-top: 1px solid #444;
    color: #ccc;
}

/* Responsive Design */
@media (max-width: 768px) {
    .main-content {
        padding: 1rem;
    }
    
    .hero-section h1 {
        font-size: 2.2rem;
    }
    
    .hero-section p {
        font-size: 1rem;
    }
    
    .subjects-grid {
        grid-template-columns: 1fr;
    }
    
    .class-title {
        font-size: 1.6rem;
    }
    
    .nav-links {
        display: none;
    }
}

@media (max-width: 480px) {
    .subject-stats {
        flex-direction: column;
        gap: 0.75rem;
    }
    
    .hero-section h1 {
        font-size: 1.8rem;
    }
    
    .subject-card {
        padding: 1.5rem;
    }
}

/* Ad Responsive */
@media (max-width: 728px) {
    .ad-container {
        max-width: 100%;
    }
}
/* Two buttons side by side styling */
.subject-actions {
    display: flex;
    justify-content: center;
    gap: 0.75rem;
    margin-top: 1.5rem;
}

.subject-actions .btn {
    flex: 1;
    min-width: 120px;
    font-size: 0.9rem;
    padding: 0.8rem 1.2rem;
}

.btn-secondary {
    background: linear-gradient(45deg, #00b894, #00cec9) !important;
    color: white !important;
    border: none !important;
}

.btn-secondary:hover {
    background: linear-gradient(45deg, #00a085, #00b7b8) !important;
    transform: translateY(-2px);
}

/* Mobile responsive */
@media (max-width: 480px) {
    .subject-actions {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .subject-actions .btn {
        flex: none;
        width: 100%;
        font-size: 0.85rem;
    }
}
/* Three buttons layout */
.subject-actions {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    margin-top: 1.5rem;
    flex-wrap: wrap;
}

.subject-actions .btn {
    flex: 1;
    min-width: 110px;
    font-size: 0.85rem;
    padding: 0.75rem 1rem;
}

.btn-success {
    background: linear-gradient(45deg, #fdcb6e, #e17055) !important;
    color: white !important;
    border: none !important;
}

.btn-success:hover {
    background: linear-gradient(45deg, #f39c12, #d35400) !important;
    transform: translateY(-2px);
}

/* Mobile responsive */
@media (max-width: 600px) {
    .subject-actions {
        flex-direction: column;
        gap: 0.75rem;
    }
    
    .subject-actions .btn {
        flex: none;
        width: 100%;
        font-size: 0.9rem;
    }
}