How do i remove these margins?

Question

I have created a roll-over effect in which the rollovers enters from the top of the box. However for some reason there seems to be a small grey margin either side of the div which i have not purposely choosen. Have i put something in the css which i do not need?
.sweep-to-bottom {
  width: 49%;
  display: inline-block;
  vertical-align: middle;
  -webkit-transform: translateZ(0);
  transform: translateZ(0);
  -webkit-backface-visibility: visible;
  backface-visibility: visible;
  -moz-osx-font-smoothing: grayscale;
  position: relative;
  -webkit-transition-property: color;
  transition-property: color;
  -webkit-transition-duration: 0.7s;
  transition-duration: 0.7s;
  margin-bottom: 1%;
  margin-right: 1%;
.sweep-to-bottom img {
  display: block;
.sweep-to-bottom:before {
  content: "";
  position: absolute;
  z-index: 99;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  -webkit-transform: scaleY(0);
  transform: scaleY(0);
  -webkit-transform-origin: 50% 0;
  transform-origin: 50% 0;
  -webkit-transition-property: transform;
  transition-property: transform;
  -webkit-transition-duration: 0.7s;
  transition-duration: 0.7s;
  -webkit-transition-timing-function: ease-out;
  transition-timing-function: ease-out;
   background-image:url(../Graphics/Projects/Product%20Images/Durham%20Business%20School/Dur hamBusiness-Hover.png);
  background-position: center;
  background-size: contain;
  background-repeat: no-repeat;
sweep-to-bottom:hover, sweep-to-bottom:focus, sweep-to-bottom:active {
  color: white;
.sweep-to-bottom:hover:before, .sweep-to-bottom:focus:before, .sweep-to-bottom:active:before {
  -webkit-transform: scaleY(1);
  transform: scaleY(1);
The unwanted margins are the to small grey rectangles on the left and right. Which are the same thing you get if you highlight any text.
Thanks!

Answer 1

Could this be causing it?
  margin-bottom: 1%;
  margin-right: 1%;
A link to your online page would be more helpful.
Or you could try analyzing this yourself in a browser with Inspect Element feature.
Nancy O.