style.scss

#main-header {
  img {
    width: 100%;
    height: 100%;
  }

  .port-item {
    width: 25%;
    &:hover {
      opacity: 0.8;
      cursor: pointer;
    }
  }
}

.bg-black {
  color: #fff;
  background: #000;
}

@media (min-width: 1199px) {
  // the 3em is determined by exprience!!
  .port-item {
    padding: 3em !important;
  }
}