body {
    margin: 0;
    font-family: monospace;
    background: linear-gradient(125deg, #1f2937, #111827);
    color: white;
    transition: background 0.4s ease, color 0.4s ease;
}

body.light {
    background: linear-gradient(135deg, #f3f4f6, #e5e7eb);
    color: #111827;
}

#controls {
    position: absolute;
    top: 20px;
    right: 20px;
    display: flex;
    gap: 15px;
}

#timezoneSelect {
    padding: 8px 12px;
    border-radius: 8px;
    border: none;
    font-family: monospace;
    font-weight: bold;
}

#themeToggle {
    padding: 8px 12px;
    border-radius: 8px;
    border: none;
    font-size: 1rem;
    cursor: pointer;
    background: #3b82f6;
    color: white;
}

#clock-container {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
}

#clock {
    font-size: 5rem;
    padding: 30px 60px;
    border-radius: 20px;
    background: rgba(0, 0, 0, 0.35);
    backdrop-filter: blur(10px);
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.5);
    transition: transform 0.2s ease;
    cursor: pointer;
}

body.light #clock {
    background: rgba(255, 255, 255, 0.6);
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
}

.tick {
    transform: scale(1.05);
}