html {
    background-color: #3a0a40;
}
/* Gamified background with animated elements */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: 
        radial-gradient(circle at 20% 50%, rgba(255, 255, 255, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(255, 255, 255, 0.05) 0%, transparent 50%);
    pointer-events: none;
    z-index: -1;
}
/* Mobile-first responsive design */
body {
    margin: 0;
    padding: 16px;
    font-family: 'Arial', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    overflow-x: hidden;
}
/* Mobile styles (default) */
/* body {
    padding: 16px;
} */

a {
    color: white;
    text-decoration: none;
}
nav {
    padding-bottom: 10px;
}

/* Tablet styles */
@media (min-width: 768px) {
    body {
        padding: 24px;
        background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    }
}

/* Desktop styles */
@media (min-width: 1024px) {
    body {
        padding: 32px;
        background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    }
}

/* Header styles */
header {
    text-align: center;
    margin-bottom: 40px;
    color: white;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 8px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

header p {
    font-size: 1.2rem;
    opacity: 0.9;
    margin: 0;
}

/* Main content */
main {
    max-width: 1200px;
    margin: 0 auto;
}

/* Topics grid */
.topics-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
    margin-top: 20px;
}

/* Tablet: 2 columns */
@media (min-width: 768px) {
    .topics-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 24px;
    }
}

/* Desktop: 3 columns */
@media (min-width: 1024px) {
    .topics-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 28px;
    }
}

/* Large desktop: 4 columns */
@media (min-width: 1400px) {
    .topics-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

/* Topic cards */
.topic-card {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 12px;
    padding: 24px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    cursor: pointer;
}

.topic-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
}

.topic-card h3 {
    margin: 0 0 12px 0;
    color: #333;
    font-size: 1.4rem;
    font-weight: 600;
}

.topic-card p {
    margin: 0;
    color: #666;
    line-height: 1.5;
    font-size: 0.95rem;
}

iframe {
    visibility: hidden;
    display: none;
    width: 100vw;
    height: 100vh;
    top: 0;
    left: 0;
    position: fixed;
    border: none;
    opacity: 0;
}