.telephone {
  position: fixed;
  bottom: 0;
  right: 0;
  background-color: lightgreen;
  border-top-left-radius: 100%;
  width: 42px;
  height: 42px;
  border-left: 1px solid black;
  border-top: 1px solid black;
}
@media only screen and (min-width: 768px) {
  .telephone {
    width: 60px;
    height: 60px;
  }
}
@media only screen and (min-width: 1000px) {
  .telephone {
    width: 85px;
    height: 85px;
  }
}
@media only screen and (min-width: 1200px) {
  .telephone {
    width: 60px;
    height: 60px;
  }
}
.telephone a {
  color: black;
  position: absolute;
  bottom: 2px;
  right: -2px;
}
.telephone a i {
  font-size: 2.5rem;
}
@media only screen and (min-width: 768px) {
  .telephone a i {
    font-size: 3.5rem;
  }
}
@media only screen and (min-width: 1000px) {
  .telephone a i {
    font-size: 4.8rem;
  }
}
@media only screen and (min-width: 1200px) {
  .telephone a i {
    font-size: 3.5rem;
  }
}