Split button

HTML

<a href="#">Link text</a>

CSS

body {
  text-align: center;
}
a {
  position: relative;
  margin-top: 2em;
  display: inline-block;
  color: #000;
  text-decoration: none;
  padding: 0 4em;
  border: 3px solid #005895;
  line-height: 3em;
}
a:after {
  content: "";
  position: absolute;
  top: -3px;
  bottom: -3px;
  right: -3px;
  left: 50%;
  border: 3px solid #E31E30;
  border-left: none;
}