m1 {
  position: relative;
  display: inline-block;
  margin-bottom: 1em;
}
m1:before {
  content: '';
  position: absolute;
  bottom: -15px;
  display: inline-block;
  width: 60px;
  height: 5px;
  left: 50%;
  -webkit-transform: translateX(-50%);
  transform: translateX(-50%);
  background-color: red;
  border-radius: 2px;
}


m2{
  position: relative;
  display: inline-block;
  margin-bottom: 1em;
}
m2:before {
  content: '';
  position: absolute;
  bottom: -15px;
  display: inline-block;
  width: 60px;
  height: 5px;
  left: 50%;
  -webkit-transform: translateX(-50%);
  transform: translateX(-50%);
  background-color: blue;
  border-radius: 2px;
}

m3{
  position: relative;
  display: inline-block;
  margin-bottom: 1em;
}
m3:before {
  content: '';
  position: absolute;
  bottom: -15px;
  display: inline-block;
  width: 60px;
  height: 5px;
  left: 50%;
  -webkit-transform: translateX(-50%);
  transform: translateX(-50%);
  background-color: yellow;
  border-radius: 2px;
}


m4{
  position: relative;
  display: inline-block;
  margin-bottom: 1em;
}
m4:before {
  content: '';
  position: absolute;
  bottom: -15px;
  display: inline-block;
  width: 60px;
  height: 5px;
  left: 50%;
  -webkit-transform: translateX(-50%);
  transform: translateX(-50%);
  background-color: green;
  border-radius: 2px;
}