.wrap {

  width: 400px; /* absolute in pixels */

  width: 10vw; /* 1vw is equal to 1% of the width of the viewport */

  width: 4in; /*inches, is converted in pixels 1in == 96px*/

  width: 20cm; /*Centimeters, is converted in pixels 1cm = 37.8px*/

  width: 200mm; /*milimeters, is converted in pixels 1mm = 0.1cm = 3.78px*/

  width: 40em; /*It changes when you change the font-size (default 1em = 16px) */

  width: 40rem; /*Relative unit to the root*/

  width: 120pt; /* 1in = 72pt */

  width: 12pc; /* Same as point 1pc = 12pt */

  width: 60ex; /*This is a measurement based on the x-height of the current font*/

  width: 60ch; /*only ch is based on the width of the zero (0)*/

}