mat-slide-toggle css theme code example
Example: mat slide toggle change color
::ng-deep .mat-slide-toggle.mat-checked:not(.mat-disabled) .mat-slide-toggle-thumb {
background-color: blue; /*replace with your color*/
}
::ng-deep .mat-slide-toggle.mat-checked:not(.mat-disabled) .mat-slide-toggle-bar {
background-color: skyblue; /*replace with your color*/
}