Text input colors when using light color scheme

Here is the "Contact" page of my site:
https://jayaustindesigns.com/contact

I'm using the Lukas theme with the color scheme switched to light.

On my "Contact" page, the text input boxes are black with white text, which looks very odd on a light page.  Similarly, the "Submit" button is white with black text, which could be easy to miss on a light page.  Can I make these inputs be white with black text?  Can I make this button be black with white text?  These seem like things that should change when I select the light color scheme, but they do not.

(FWIW, the same issue occurs with the Ludwig theme, as well.  These are the only two themes that default to a dark color scheme.)

Please let me know if there is a way to have light text boxes and a dark submit buton with the Lukas theme.  Thanks!