body {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}
main {
    flex: 1;
}
.list-group-item-action {
    font-size: 1.1rem;
}
#timer {
    font-size: 1.5rem;
    font-weight: bold;
    color: #dc3545;
}