Total newb looking for help making small adjustments to an existing character sheet

I want to use the Electric Bastionland character sheet by morgdalaine in my campaign, but I'd like to switch some of the wording to fit my setting better (The Ultraviolet Grasslands).  I was hoping that I could just copy the raw contents of the html, css and json files from Github and paste it into the custom character sheet in Roll20 and then just muddle through to change the content myself. I'm stuck on the first step, because when I copy the contents into the custom Roll20 sheet, the Electric Bastionland sheet isn't reproduced. In the preview it the layout looks good, but it's missing all the text. And when I load it in the game, the text is there, but the layout isn't (everything is in a single column with the default font). Clearly I'm missing something, but I don't know what. Can anyone help? I'm trying to use an existing (and excellent) character sheet and just tweak some of the contents to fit my game setting.

You need to copy all three of html, css, and translations.json files, and paste them in the right tabs. When you copy the files from github, make sure you are copying the RAW file - click the raw button at the top right. Finally, and this is really important: ignore the preview window. It doesnt show everything properly. Just save the campaign and load it.

Thanks. I am copying the raw content of all three files into the right tabs (just quadruple checked that now). I'm also loading the campaign to check the sheet. It's not working, even though the original Electric Bastionland sheet does work perfectly when I select it as the character sheet template in the game settings. Copy-paste the raw files and load the game is all I'm doing. Is there something I've missed?

The electric bastionland sheet is a legacy sheet. Make sure you are enabling legacy sanitization.

Oh man, that solved it. Thank you Scott C!