body {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

main {
    flex: 1;
}

.card {
    box-shadow: 0 0 15px rgba(0, 0, 0, 0.1);
}

#timer {
    font-family: monospace;
    font-size: 1.5rem;
    font-weight: bold;
}

.alert {
    border-left: 5px solid;
}

.alert-info {
    border-left-color: var(--bs-info);
}

.alert-danger {
    border-left-color: var(--bs-danger);
}

.alert-success {
    border-left-color: var(--bs-success);
}

.btn {
    margin: 0.25rem;
}