.btn {
  font-family: 'Roboto', sans-serif;
  min-width: 100px;
  font-size: 0.9rem;
  padding: 10px 20px;
  box-sizing: border-box;
  cursor: pointer;
  display: inline-block;
  align-items: center;
  justify-content: center;
  text-align: center;
  text-decoration: none;
  transition: 0.3s;
  border-radius: 4px;
  white-space: nowrap;
  font-weight: 500;
  vertical-align: middle;
  margin: 5px;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.5);
}

.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.ripple {
  position: relative;
  overflow: hidden;
  transform: translate3d(0, 0, 0);
}

.ripple:after {
  content: "";
  display: block;
  position: absolute;
  width: 100%;
  height: 100%;
  top: 0;
  left: 0;
  pointer-events: none;
  background-image: radial-gradient(circle, #fff 10%, transparent 10.01%);
  background-repeat: no-repeat;
  background-position: 50%;
  transform: scale(10, 10);
  opacity: 0;
  transition: transform .5s, opacity 1s;
}

.ripple:active:after {
  transform: scale(0, 0);
  opacity: .3;
  transition: 0s;
}
