body font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", sans-serif;
But this is rarely necessary. Use the system font stack approach unless you are certain the user is on an Apple device with that font installed. hirakakupro w3 font
To explicitly request W3 (regular):
It seems you're looking for a (i.e., web-safe or web-font usage). body font-family: system-ui