CSS3 Кнопки

№1

<a class="btn1" href="">Button</a>

a.btn1 {
  text-decoration: none;
  outline: none;
  display: inline-block;
  padding: 12px 40px;
  margin: 10px 20px;
  border-radius: 30px;
  background-image: linear-gradient(45deg, #6ab1d7 0%, #33d9de 50%, #002878 100%);
  background-position: 100% 0;
  background-size: 200% 200%;
  font-family: 'Montserrat', sans-serif;
  font-size: 24px;
  font-weight: 300;
  color: white;
  box-shadow: 0 16px 32px 0 rgba(0,40,120,.35);
  transition: .5s;
}
a.btn1:hover {
  box-shadow: 0 0 0 0 rgba(0,40,120,0);
  background-position: 0 0;
}

№2

<a href="" class="btn2">Узнать больше</a>
.btn2 {
    text-decoration: none;
    display: inline-block;
    position: relative;
    height: 40px;
    line-height: 40px;
    padding: 0 20px;
    color: white;
    font-size: 14px;
    background: #383d48; 
    /*box-shadow: 0 0 1px rgba(0, 0, 0, 0);*/
}

.btn2:before {
    content: "";
    position: absolute;
    height: 0;
    width: 0;
    top: 0;
    right: 0;
    background: linear-gradient(225deg, #BEFDE6 45%, #aaaaaa 50%, #cccccc 56%, white 80%);
    /*box-shadow: -1px 1px 1px rgba(0, 0, 0, .4);*/
    transition: .3s;
}

.btn2:hover:before {
    width: 20px;
    height: 20px;
}

№3

<a class="btn3" href="">Button</a>

.btn3 {
  text-decoration: none;
  outline: none;
  display: inline-block;
  color: white;
  padding: 20px 30px;
  margin: 10px 20px;
  border-radius: 10px;
  font-family: 'Montserrat', sans-serif;
  text-transform: uppercase;
  letter-spacing: 2px;
  background-image: linear-gradient(to right, #9EEFE1 0%, #4830F0 51%, #9EEFE1 100%);
  background-size: 200% auto;
  box-shadow: 0 0 20px rgba(0,0,0,.1);
  transition: .5s;
}
.btn3:hover {background-position: right center;}