check box not shown / missing

[Grutsch]

Bug description

When using "Matrixfrage" or "Multiple Choice Frage" the checkbox is not displayed

Screenshots

Environment

Contao 4.13.37
MATE Theme 2.21.0

[Grutsch]

it is a css problem.
fix with ertanl css
[type='radio']:not(:checked) {
opacity: 1;
}