Sorry that I am late but I too faced the same problem recently so I am sharing how I fixed it (at least in my case)
When I was facing this problem, I looked up in almost all sites and forums but I didn't get a working solution that satisfied me. hence I went to the official css library https://cdnjs.cloudflare.com/ajax/libs/materialize/1.0.0/css/materialize.min.css and changed the core values according to my needs.
For the checkbox tick mark, I need to change the color in two cases:
First is when the user check the box by mouse click, second is when the user press tab and pressing spacebar for checking the box.
So the following change might work for you:
[type="checkbox"].filled-in:checked+span:not(.lever):before{
border-right:2px solid cyan;
border-bottom:2px solid cyan;
}
[type="checkbox"].filled-in:checked+span:not(.lever):after{
border:2px solid black;
background-color:black;
}
[type="checkbox"].filled-in.tabbed:checked:focus+span:not(.lever):after{
background-color:black;
border-color:black;
}
If you want the full code visit https://codepen.io/MrSrv7/pen/RwaNeyd
I have created a simple login form with HTML CSS and JS,
Demo/Preview here: https://mrsrv7.github.io/LoginForm/
Repository here: https://github.com/MrSrv7/LoginForm/