Looking for help with css for a button- hover/active/link/visited and aligning text in the button

I'm working on a wordpress website and am using a plugin to handle logging in/out on my home page. I have been working on the css for the button - but cannot get a few things to work. I'm trying to align the text in the button to the middle of the button and also have the button have the same look that it only appears to have when I hover (the brighter blue and white -- like the two lower buttons, which were created in a different plugin).

Here's my website address: http://www.cri-mms.com/newsite/
The button in question is labeled "Log In for Support". I'd like it to look like the buttons below it (which I did not code, but came from another plugin). Thanks for your help!

Here's my css (most of it works,except the look of it when hovering on it while on the page - is the look i want for all of its states)

input.buttonstyle {font-family: arial; font-size: 14px; color: white; width: 150px; 
height: 25px; border-radius: .5em;background-color: #052f4f; border: none; border-shadow:none;
 padding-bottom:3px;margin-bottom: 5px;text-align:center; vertical-align: middle;}
 input[type="submit"]:hover { color: white;background-color: #052f4f;}
 input[type="submit"]:active { color: white;background-color: #052f4f;}
 input[type="submit"]:visited { color: white;background-color: #052f4f;}
 input[type="submit"]:link { color: white;background-color: #052f4f;} 
a.buttonstyle:hover {color: white;background-color: green;} 
a.buttonstyle:active {color: white;background-color: #052f4f;}