.btn-class-name {
  --primary: 255, 90, 120;
  --secondary: 150, 50, 60;
  width: 60px;
  height: 50px;
  border: none;
  outline: none;
  cursor: pointer;
  user-select: none;
  touch-action: manipulation;
  outline: 10px solid rgb(var(--primary), .5);
  border-radius: 100%;
  position: relative;
  transition: .3s;
}

.btn-class-name .back {
  background: rgb(var(--secondary));
  border-radius: 100%;
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
}

.btn-class-name .front {
  background: linear-gradient(0deg, rgba(var(--primary), .6) 20%, rgba(var(--primary)) 50%);
  box-shadow: 0 .5em 1em -0.2em rgba(var(--secondary), .5);
  border-radius: 100%;
  position: absolute;
  border: 1px solid rgb(var(--secondary));
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 1.2rem;
  font-weight: 600;
  font-family: inherit;
  transform: translateY(-15%);
  transition: .15s;
  color: rgb(var(--secondary));
}

.btn-class-name:active .front {
  transform: translateY(0%);
  box-shadow: 0 0;
}