DevTools not creating styles in local version of file?

Question

Google Chrome

Created an html file on the desktop. Made a sign. I want to write my own style for tr (any element), I click on the plus sign "new style rule" then "Tab" and the window resets. I also move the mouse and click to enter the styles for the element and again fail.
In mozilla, everything works both in local and in the combat version. On the Internet, the functionality works, in the local version it does not.