Looks like you change tried to either edit the theme of the project or you did changes to the layout or both.
You can do 1 thing:
- Keep this project aside
- create a new project and run that to generate all files in the local filesystem properly
- open this new project in your File explorer and go to the theme directory and go inside the web directory and copy all the files in it
- go back to the filesystem of your old project(the one which has the issue)
- go to theme directory > web directory > overwrite all files and folders with the contents you have copied
- run this project and see if all works
good luck