<!-- Hover #1 -->
<div class="box-1">
  <div class="btn btn-one">
    <span>HOVER ME</span>
  </div>
</div>
 
<!-- Hover #2 -->
<div class="box-2">
  <div class="btn btn-two">
    <span>HOVER ME</span>
  </div>
</div>

<!-- Hover #3 -->
<div class="box-3">
  <div class="btn btn-three">
    <span>HOVER ME</span>
  </div>
</div>

@import 'https://fonts.googleapis.com/css?family=Open+Sans+Condensed:300';

html,
body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  margin: 0;
  display: flex;
  flex-direction: column;
  flex-wrap: wrap;
  font-family: 'Open Sans Condensed', sans-serif;
}

div[class*=box] {
  height: 33.33%;
  width: 100%; 
  display: flex;
  justify-content: center;
  align-items: center;
}

.box-1 { background-color: #FF6766; }
.box-2 { background-color: #3C3C3C; }
.box-3 { background-color: #66A182; }

.btn {
  line-height: 50px;
  height: 50px;
  text-align: center;
  width: 250px;
  cursor: pointer;
}

/* 
========================
      BUTTON ONE
========================
*/
.btn-one {
  color: #FFF;
  transition: all 0.3s;
  position: relative;
}
.btn-one span {
  transition: all 0.3s;
}
.btn-one::before {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
  opacity: 0;
  transition: all 0.3s;
  border-top-width: 1px;
  border-bottom-width: 1px;
  border-top-style: solid;
  border-bottom-style: solid;
  border-top-color: rgba(255,255,255,0.5);
  border-bottom-color: rgba(255,255,255,0.5);
  transform: scale(0.1, 1);
}
.btn-one:hover span {
  letter-spacing: 2px;
}
.btn-one:hover::before {
  opacity: 1; 
  transform: scale(1, 1); 
}
.btn-one::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
  transition: all 0.3s;
  background-color: rgba(255,255,255,0.1);
}
.btn-one:hover::after {
  opacity: 0; 
  transform: scale(0.1, 1);
}


/* 
========================
      BUTTON TWO
========================
*/
.btn-two {
  color: #FFF;
  transition: all 0.5s;
  position: relative; 
}
.btn-two span {
  z-index: 2; 
  display: block;
  position: absolute;
  width: 100%;
  height: 100%; 
}
.btn-two::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
  transition: all 0.5s;
  border: 1px solid rgba(255,255,255,0.2);
  background-color: rgba(255,255,255,0.1);
}
.btn-two::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
  transition: all 0.5s;
  border: 1px solid rgba(255,255,255,0.2);
  background-color: rgba(255,255,255,0.1);
}
.btn-two:hover::before {
  transform: rotate(-45deg);
  background-color: rgba(255,255,255,0);
}
.btn-two:hover::after {
  transform: rotate(45deg);
  background-color: rgba(255,255,255,0);
}


/* 
========================
      BUTTON THREE
========================
*/
.btn-three {
  color: #FFF;
  transition: all 0.5s;
  position: relative;
}
.btn-three::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
  background-color: rgba(255,255,255,0.1);
  transition: all 0.3s;
}
.btn-three:hover::before {
  opacity: 0 ;
  transform: scale(0.5,0.5);
}
.btn-three::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
  opacity: 0;
  transition: all 0.3s;
  border: 1px solid rgba(255,255,255,0.5);
  transform: scale(1.2,1.2);
}
.btn-three:hover::after {
  opacity: 1;
  transform: scale(1,1);
}