Customizing sign up page buttons using CSS

Hi,

I had earlier asked for a small custom button on the sign up page to match my theme (Divi). The code given was,

.mu_register {
	padding-top: 50px;
	max-width: 60%
}

.mu_register input[type="submit"], .mu_register #blog_title, .mu_register #user_email, .mu_register #blogname, .mu_register #user_name {
	width: auto !important;
}

.mu_register input[type="submit"] {
	font-size: 20px;
	font-weight: 500;
	border-radius: 3px;
	padding: 6px 20px;
	line-height: 1.7em;
	background: none repeat scroll 0% 0% transparent;
	border: 2px solid;
	-moz-osx-font-smoothing: grayscale;
	transition: all 0.2s ease 0s;
	position: relative;
	color: #666;
}

It worked fine but after updating the Divi theme to 2.4, using this code causes conflict with CTA button module in the theme.

Can anyone change this code in a way that it does'nt conflict with the theme?

What I wanted is to
1.bring the sign up page contents to center
2.replace the "Next Button" and "Signup" button style to look like Divi Button. (In case if you can't make it look like divi button, make it small and bring it to center and give a little style to look good.)

I also had given access to my site, so that you can paste the above code and look for yourself how the code worked. You can paste the code in Divi>Theme options>custom CSS

Please help with this simple CSS style.
Thank you.