UI fontsThe ui-serif, ui-sans-serif, ui-monospace and ui-rounded values for the font-family CSS property use device-default user interface fonts for text.fontsFontslimitedhttps://drafts.csswg.org/css-fonts-4/#ui-serif-defextended-system-fontshttps://developer.mozilla.org/docs/Web/CSS/Reference/Properties/font-familycss.properties.font-family.ui-monospacecss.properties.font-family.ui-roundedcss.properties.font-family.ui-sans-serifcss.properties.font-family.ui-serifhttps://nowyoucanuse.com/features--font-family-ui.html