how to make fonts respnsive

h1 {
  font-size: clamp(16px, 5vw, 34px);
}

/* Uses vh and vm with calc */
@media screen and (min-width: 25em){
  html { font-size: calc( 16px + (24 - 16) * (100vw - 400px) / (800 - 400) ); }
}

/* Safari <8 and IE <11 */
@media screen and (min-width: 25em){
  html { font-size: calc( 16px + (24 - 16) * (100vw - 400px) / (800 - 400) ); }
}

@media screen and (min-width: 50em){
html { font-size: calc( 16px + (24 - 16) * (100vw - 400px) / (800 - 400) ); }
}

html { font-size: calc(1em + 1vw); }