checkbox.css

/* Styles for the hover state of the custom checkbox */
input[type='checkbox'].check-custom:hover ~ .check-toggle {
  border-color: #4a4a4a;
}

/* Styles for the focus state of the custom checkbox */
input[type='checkbox'].check-custom:focus ~ .check-toggle {
  border-color: #b0d5ff;
  box-shadow: 0 0 0 2px rgba(23, 133, 255, 0.25);
}

/* Styles for the checked state of the custom checkbox */
input[type='checkbox'].check-custom:checked ~ .check-toggle {
  border-color: #1785ff;
  background: #1785ff url(data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSIxNiIgaGVpZ2h0PSIxNiIgdmlld0JveD0iMCAwIDI0IDI0IiBmaWxsPSJub25lIiBzdHJva2U9IiNmZmZmZmYiIHN0cm9rZS13aWR0aD0iMyIgc3Ryb2tlLWxpbmVjYXA9InJvdW5kIiBzdHJva2UtbGluZWpvaW49InJvdW5kIj48cG9seWxpbmUgcG9pbnRzPSIyMCA2IDkgMTcgNCAxMiI+PC9wb2x5bGluZT48L3N2Zz4=) center no-repeat;
  background-size: 75%;
}