start quiz button

You can hack the plugin css since nearly every style is marked as important:
Go to: wp-content>>plugins>>wp-pro-quiz>>css>>wpProQuiz_front.min.css
Then find the rule you want to change like:
.wpProQuiz_button,.wpProQuiz_button:hover
then change the background hex.

Or even with the importants in the plugin stylesheet you can be more specific in your theme’s stylesheet. Such as:
div .wpProQuiz_button{
background: #f00 !important;
}

OK,cheers. So, it’s the minified version of the css that’s active?
Or, as you say – add to theme css, targeting that div
Thanks

In the theme css is the best way.

example:

input.wpProQuiz_button, input.wpProQuiz_button:hover {
	background:red !important;
}