:root {
    --primary-color: #007bff;
    --secondary-color: #6c757d;
    --background-color: #ffffff;
    --text-color: #000000;
    --font-family: Arial, sans-serif;
}

body {
    font-family: var(--font-family);
    background-color: var(--background-color);
    color: var(--text-color);
    margin: 0;
    padding: 0;
}

header {
    background-color: var(--primary-color);
    color: #ffffff;
    padding: 20px;
    text-align: center;
}

main {
    padding: 20px;
}

section {
    margin-bottom: 40px;
}

#filters {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 20px;
}

#filters label {
    flex: 1;
}

#filters select, #filters button {
    padding: 10px;
    font-size: 16px;
}

#dinosaur-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 20px;
}

.dinosaur-card {
    border: 1px solid #ddd;
    border-radius: 8px;
    padding: 20px;
    text-align: center;
    transition: transform 0.2s;
}

.dinosaur-card:hover {
    transform: scale(1.05);
}

#timeline-container {
    position: relative;
    width: 100%;
    height: 200px;
    background: #f0f0f0;
    border: 1px solid #ddd;
    border-radius: 8px;
    overflow: hidden;
}

.timeline-marker {
    position: absolute;
    width: 2px;
    background: var(--primary-color);
    top: 0;
    bottom: 0;
}

.timeline-label {
    position: absolute;
    background: #ffffff;
    padding: 5px 10px;
    border-radius: 4px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    white-space: nowrap;
}

.hidden {
    display: none;
}

button {
    padding: 10px 20px;
    font-size: 16px;
    cursor: pointer;
    border: none;
    border-radius: 4px;
    background-color: var(--primary-color);
    color: #ffffff;
    transition: background-color 0.2s;
}

button:hover {
    background-color: #0056b3;
}

@media (prefers-color-scheme: dark) {
    :root {
        --background-color: #121212;
        --text-color: #ffffff;
    }

    body {
        background-color: var(--background-color);
        color: var(--text-color);
    }

    header {
        background-color: #1e1e1e;
    }

    .dinosaur-card {
        background-color: #1e1e1e;
        color: #ffffff;
    }

    button {
        background-color: #ffffff;
        color: #000000;
    }

    button:hover {
        background-color: #dcdcdc;
    }
}