<div class="wrapper">
  <button>Click me</button>
</div>

@import url(https://fonts.googleapis.com/css?family=Oswald);

body {
  margin: 0;
  padding: 0;
}

.wrapper {
  width: 100vw;
  height: 100vh;
  display:flex;
  justify-content: center;
  align-items: center;
}

button {
  background: red;
  color: white;
  border: none;
  padding: 20px;
  font-family: "Oswald", sans-serif;
  font-size: 1.6rem;
  cursor: pointer;
  outline: inherit;
  border-radius: 15px;
  box-shadow: 5px 5px 5px       #000;
  }

button:hover {
  filter:brightness(120%);
  box-shadow: 10px 10px 10px #000
}

button:active {
    box-shadow: inset 2px 2px 10px #000;
}

button::after {
    content:"";
    display: block;
    height: 5px;
    width: 0;
    background-color: #fff;
    transition: 0.1s width linear;
    margin: 0 auto;
}

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