On my site I am using localStorage so when a User selects a theme it then applies said theme to the relevant pages.

now this works for each individual user, however if you logout of account 1 and login with account 2 on the same device it applies it to all other accounts logged into that device.

Furthermore when the theme has been applied if I was to login on a different device it still shows the default theme?

how would I have it only affect the specific account and have the theme choice shared across devices?

Down below is the Codepen and full code:

However Please go to Codepen to see the script I was unable to upload the code correctly parts of the formatting are being ignored.

Codepen: https://codepen.io/Elixble/pen/RwzZaWB

Follow this link to see the corresponding .php page: https://codepen.io/Elixble/pen/RNbxZvz?editors=1000

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