button Try

body
  background: #333

button
  position: absolute
  top: 50%
  left: 50%
  margin: -30px 0 0 -60px
  height: 60px
  width: 120px
  border: 0
  font: bold 24px/#{60px} sans-serif
  text-transform: uppercase
  color: white
  background: #f00
  cursor: pointer
  transition: background 3s
    
  &:hover
    background: #0f0