Why is CSS bottom:0 not working in JIRA instance?

I am writing CSS for my JIRA plugin but CSS bottom:0 is not working.

Hi @prathyusha.gali,

Can you give us some more details?
Are you getting an error?
Can you share your code?
What are you trying to achieve?
How are you loading your css file?

That will help us find an answer together.

I am developing an Atlassian connect spring-boot app. For that app, I have written CSS, all other CSS styles are working except “bottom:0” My HTML contains div with id “a”, the "a "CSS contains bottom:0. Bottom 0, in general should stick to the bottom of the page but in JIRA instance it is displaying somewhere in the middle.

I see, can you show a screen shot of the behavior?