button {
  border: none;
  outline: none;
  font-size: 17px;
  padding: 1em 2em;
  position: relative;
  color: #14213d;
  background: #f1f1f1;
  display: grid;
  font-weight: 700;
  place-items: center;
  transition: color 350ms linear 650ms;
  border-top-right-radius: 10px;
  border-bottom-right-radius: 10px;
  overflow: hidden;
  z-index: 1;
}

button:hover {
  color: #212529;
}

button::before,
button::after {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  z-index: -1;
  width: 0;
  height: 6%;
}

button::before {
  background: #212529;
  transition: width 350ms, height 350ms linear 650ms;
}

button:hover::before {
  width: 100%;
  height: 100%;
}

button:after {
  background: #ced4da;
  transition: width 350ms linear 175ms, height 350ms linear 650ms;
}

button:hover::after {
  width: 95%;
  height: 100%;
}