.container-font-null {
  font-size: 0;
}

.block-element {
  width: 150px;
  height: 150px;
  border: 1px solid black;
  background-color: green;
  color: yellow;
}

.inline-element {
  background-color: blue;
  color: white;
}

.big-inline-element {
  background-color: yellow;
}