It’s not a good idea to fix shortcomings in your HTML with CSS. Fix your HTML first!
You can change CSS right in your browser’s DevTools (to open them, right-click the browser window and choose “inspect” or “inspect element”). The great thing is, none of the styles will be saved so you can experiment here! Another great thing about the DevTools is the “computed styles” tab, because this shows you exactly what styles are currently applied to an element. This can be really helpful when it comes to debugging your CSS!
There are 24 tips there. I “counted” by using DevTools to change the <ul> to an <ol>. 😉