css make font size responsive code example

Example 1: responsive font-size

/* please refer to https://developer.mozilla.org/fr/docs/Web/CSS/clamp() */
font-size: clamp(40px, 10vw, 70px); /* clamp(MIN, VAL, MAX) */

Example 2: responsive text css

/* 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) ); }
}

Example 3: how to make font responsive

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