How to I increase the font size on a linked button in html code?

Website:
https://visualbrandchallenge.com

Problem:

If you look at the link, the button on the left is super tiny but is linked properly. That appears to be the default when I paste the code in without altering it. I would prefer the button on the right which is just the right size, but it isn't linked. I am having trouble figuring out where to add the code and what line of code i need to add from the smaller one to make it the link.

Code for the smaller one:

<a class="button" href="https://graphicmechanic.com/instant-quote/">Get a quote.</a>

Code for the larger, correct one:

<input

type="button" value="take the challenge"

style="font-size:30px"

>

Any assistance would be greatly appreciated!