body {
    background: #212529;
    min-height: 100vh;
    display: flex;
    align-items: center;
}

#timer-display {
    padding: 2rem 0;
}

#time {
    font-size: 5rem;
    letter-spacing: 0.1em;
}

.preset-btn {
    min-width: 3rem;
}

@media (max-width: 576px) {
    #time {
        font-size: 3.5rem;
    }
}