Where and how should I even begin to fix terrible design problems? I can't change the theme, I must learn how to fix it the current one, I guess via CSS? How to align all textboxes properly, how to change box (top is gray) color and button color as well? These are all in simple pages via shortcodes. Thanks.
Yes, this can easily be cleaned up with a little CSS. You can start by using the browser's inspector, hit F12 to open it, and select the element you want to style.
See if that form or something around has an ID, use that to target each element so you don't effect other pages or unwanted elements.
Here are couple example that might help.
#myFormID label,
#myFormID input[type="text"],
#myFormID select {
display: block;
}
That will put your labels and form elements on different lines.
The best thing to do is just inspect the page and start playing around with the CSS.
Without seeing the actual CSS that is already applied, it is difficult to say "change this and this to fix this and that."
But... to address your concern about the theme, etc. What you should be doing is using a child theme. That way you can customize your work. That allows you to customize in a way that still allows you to update if the theme developer publishes an update.
Another thing to consider is that the WordPress Customizer now has the ability for applying custom CSS within the Customizer interface.
So this may not ultimately be the answer that you need, but hopefully it has some info you can use to make the process easier.
