When the accent-color CSS property is set to white on iOS Safari, the checkmark of a checkbox is invisible. In other browsers such as Chrome and Firefox, when the accent-color is a light color, the checkmark becomes black rather than white. Example: https://codepen.io/devongovett/pen/QWmoJBq
Created attachment 461816 [details] rendering in Safari, firefox, chrome (desktop) Confirmed on iOS it becomes white on white on Desktop it becomes white on a dark grey. while other browsers sport a black mark on a white background. Probably depends on Bug 231791
There are also discussions about accent color on Bug 241866
<rdar://problem/99018889>