Enhancement in CSS of section intro_container

[aakanshimalik]

I want to add little opacity in the background image which will look better. And also i want to make heading h1 more bold to highlight it well.
@Anjaliavv51 Please assign this task to me.

[github-actions]

Hi there! Thanks for opening this issue @aakanshimalik!. We appreciate your contribution to this open-source project. We aim to respond or assign your issue as soon as possible.