postcss-px-to-viewport/example/main-viewport.css

.class {
  margin: -3.125vw .5vh;
  padding: 5vmin 2.96875vw;
  border: 0.9375vw solid black;
  font-size: 4.375vw;
  line-height: 6.25vw;
}
.class2 {
  font-size: 6.25vw;
  line-height: 9.375vw;
}
@media (min-width: 750px) {
  .class3 {
    font-size: 5vw;
    line-height: 6.875vw;
  }
}

/*
.class {
    font-size: 16px;
}
*/