.curso {
  width: calc(400px - 40px);
  margin-bottom: 30px;
  margin-left: 20px;
  margin-right: 20px;
  border-left: 1px solid rgba(0,0,0,0.2);
  border-top: 1px solid rgba(0,0,0,0.2);
  box-shadow: 2px 2px 4px 0px rgba(0,0,0,0.2);
}