Check out example codes for "DevTools failed to load SourceMap: Could not load content for bootstrap.min.css.map". It will help you in understanding the concepts better.

Code Example 1

Delete /*# sourceMappingURL=bootstrap.min.css.map */ in css/bootstrap.min.css
and delete /*# sourceMappingURL=bootstrap.css.map */ in css/bootstrap.css

It is working for me.
I hope it will work for you also.
Namaste _/\_

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