x
<html><head><style>h1 { font-size: 15vmax;}</style></head><body><h1>Hello</h1><p>Resize the browser window (both width and height) to see how the font-size of h1 changes.</p><p>1vmax = 1vw or 1vh, whichever is larger.</p><p>The vmax unit is not supported in Edge 15 and earlier, nor in Safari 6.1 and earlier.</p></body></html>