You can take this a step further to segregate passwords as well.
Reusing passwords across devices is bad. If one gets compromised you don’t want a password being out into a brute force table to be used with all your other accounts elsewhere.
This method of tagging using HTML markup styles in your passwords lets you keep the same core passphrase but alter the tagging, specific to the service.
You can do this easily while also giving you artificial password complexity.
Example:
Core passpgrase is “yogurt”
Password for gmail becomes markup with a yogurt
I only need to remember yogurt.
Every device just gets a truncated service tag appended to the beginning and end using HTML style tags.
Suddenly you have a 26+ character password that you don’t forget and doesn’t compromise you across other services because each is different.
'well actually' a file simply containing password (with no tags) will also render (on >99% of browsers). the body and h1 tags only make the text bigger and more semantically clear. if you really want to be semantic and use w3 standards, you should use !DOCTYPE html and html as well.