Just an FYI for anyone else who finds this issue: I found that overriding the styles with !important in my own custom.css file became a big issue. Notably because there are so many different classes and states, not to mention the contrast styles for UIkit buttons.
So, I ultimately decided to revise the reset.less file as suggested by Chang. However, I quickly found that simply commenting out just one line didn't resolve the problem because of the active, hover, focus states. So, I commented out the entire 'a' styling which fully resolved my problem. Below shows lines 68-84 that have been commented out.
// a {
// background: transparent;
// &:link {
// text-decoration: none;
// }
// &:hover {
// color: @link-hover-color;
// }
// &:hover,
// &:focus,
// &:active {
// color: @link-color;
// background-color: transparent;
// }
//}