.yasai-birthdate {
    display: flex;
    flex-wrap: nowrap;
    align-items: center;
    gap: 8px;
    margin-bottom: 1rem;
}
.yasai-birthdate select {
    flex: 1;
    min-width: 80px;
    padding: 8px;
    border-radius: 6px;
    border: 1px solid #ccc;
}
@media (max-width: 480px) {
    .yasai-birthdate {
        flex-wrap: wrap;
    }
}