Auto fit border to only below heading

Design help General
1

Hi!

I’m trying to have a yellow border show only below the subheading text in my “How It Works” section. My problem is that even when I set the width of my subheading to auto, the width goes well beyond the end of my text. When I then set the border, it is too long. How can I fix my width so it actually is auto and only fits in the content and no more?

Here’s my site:
https://preview.webflow.com/preview/the-bright-tutors?utm_medium=preview_link&utm_source=designer&utm_content=the-bright-tutors&preview=cd656c811bf6433b7f53c9327ad15682&mode=preview

Thanks so much for your help