button {
  border-style: outset;
  font-weight: 1000;
  height: 50px;
  width: 150px;
  background: inherit;
  border: 7px solid orange;
  transition: all 900ms;
}

button::before {
  content: "";
  z-index: -1;
  position: absolute;
  left: 50%;
  top: 0;
  bottom: 0%;
  height: 100%;
  width: 0;
  background-color: yellow;
  transition-timing-function: ease-in;
  transition: all 1.3s;
}

button:hover {
  color: rgb(78, 78, 78);
  border: 2px solid yellow;
  transform: scale(1.2);
}

button:hover::before {
  left: 0%;
  width: 100%;
}