.header button {
  border: none;
  cursor: pointer;
  height: 24px;
  margin-right: 16px;
  opacity: 0.54;
  outline: none;
  overflow: hidden;
  text-indent: -30000px;
  transition: opacity 0.333s cubic-bezier(0, 0, 0.21, 1);
  width: 24px;
}

.header #butRefresh {
  background: url(/images/refresh.svg) center center no-repeat;
}

.header #butInstall {
  background: url(/images/install.svg) center center no-repeat;
}