:root {
    --bg-color: #f0f2f5;
    --text-color: #333;
    --card-bg: #fff;
    --card-shadow: rgba(0, 0, 0, 0.1);
    --h1-color: #333;
}

[data-theme="dark"] {
    --bg-color: #121212;
    --text-color: #e0e0e0;
    --card-bg: #1e1e1e;
    --card-shadow: rgba(0, 0, 0, 0.5);
    --h1-color: #fff;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    text-align: center;
    margin: 0;
    padding: 2rem;
    transition: background-color 0.3s, color 0.3s;
}

h1 {
    font-size: 3rem;
    color: var(--h1-color);
    margin-bottom: 2rem;
}

#theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 10px 20px;
    border-radius: 20px;
    border: none;
    cursor: pointer;
    background-color: var(--card-bg);
    color: var(--text-color);
    box-shadow: 0 4px 8px var(--card-shadow);
    font-weight: bold;
    transition: all 0.3s;
}

#theme-toggle:hover {
    transform: scale(1.05);
}

#clocks-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.clock {
    background-color: var(--card-bg);
    padding: 1.5rem;
    border-radius: 10px;
    box-shadow: 0 4px 8px var(--card-shadow);
    transition: transform 0.2s, background-color 0.3s, box-shadow 0.3s;
}

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

.city {
    font-size: 1.5rem;
    font-weight: bold;
    margin-bottom: 0.5rem;
}

.time {
    font-size: 2rem;
    font-family: 'Courier New', Courier, monospace;
}