The easiest way to fix it would be to shorten the text on the button. (It looks as though the button is sized by how much text it has to accommodate.)
So, for example, changing the text to "Accept All Policy Terms."
Even though you say the problem is the button is too small, when I looked on my phone the issue is the button is the entire width of the screen, which causes it to blend in with the other text. Moreover, sometimes browsers will shrink something to try to fit it on a screen because the length of the text doesn't contain a line break. In any case, that's a lot of text to fit in a single line on a "button."
I'd at least give shorter wording a try.