/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #333;
    background: #d7dce3;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Header */
header {
    background: #2c3e50;
    color: white;
    padding: 1rem 0 1rem;
    text-align: center;
}

header h1 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 0rem;
}

.tagline {
    font-size: 1.1rem;
    opacity: 0.95;
    font-weight: 400;
}

/* Main content */
main {
    padding: 3rem 0 2rem;
}

/* Dataset cards */
.datasets {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
    margin-top: 1rem;
    margin-bottom: 1rem;
}

.dataset-card {
    background: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
    transition: transform 0.2s, box-shadow 0.2s;
    text-decoration: none;
    display: block;
}

.dataset-card:hover,
.dataset-card:active {
    transform: scale(1.03);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
}

.card-header {
    background: #2c3e50;
    color: white;
    padding: 1rem 1.25rem;
    font-size: 1.25rem;
    font-weight: 600;
}

.card-preview {
    position: relative;
    height: 300px;
    background: #e8f4f8;
    overflow: hidden;
}

.card-preview img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.card-count {
    position: absolute;
    top: 10px;
    right: 10px;
    background: rgba(255, 255, 255, 0.95);
    padding: 0.5rem 0.75rem;
    border-radius: 4px;
    font-size: 0.875rem;
    font-weight: 600;
    color: #2c3e50;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

/* About section */
.about {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    margin-bottom: 2rem;
}

.about h2 {
    font-size: 1.75rem;
    margin-bottom: 1rem;
    color: #2c3e50;
}

.about p {
    color: #666;
    margin-bottom: 1rem;
    line-height: 1.7;
}

.about p:last-child {
    margin-bottom: 0;
}

/* Footer */
footer {
    background: #34495e;
    color: white;
    padding: 2rem 0;
    text-align: center;
    margin-top: 3rem;
}

footer p {
    font-size: 0.875rem;
    opacity: 0.8;
    margin-bottom: 0.25rem;
}

footer a {
    color: #7fb3d3;
    text-decoration: none;
}

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

/* Tablet and up */
@media (min-width: 640px) {
    .datasets {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* Desktop */
@media (min-width: 1024px) {
    header h1 {
        font-size: 2.5rem;
    }
    
    .tagline {
        font-size: 1.25rem;
    }
    
    .datasets {
        grid-template-columns: repeat(3, 1fr);
        gap: 2rem;
    }
    
    .card-image {
        height: 140px;
    }
    
    main {
        padding: 3rem 0;
    }
}