Change the Border Color of the empty (un-checked) check box in Materialize

I've found instructions on change the color of the actual check mark when it's checked, but I'm trying to figure out how to change the color of the box.

I'm placing the box on a darker background, and it's hard to see, so I'd like to make it lighter.

I've tried the normal color class concepts that most of the other elements observe in Materialize, but the empty checkbox border doesn't seem to follow it.

<span class="card-title">
    <input type="checkBox" id="" class="checkbox  selectFromWeb white"  />
    <label for=""></label>
</span>

Any help is greatly appreciated.