improve mobile friendliness

- Text is way too large, respective [helpers](https://bulma.io/documentation/helpers/typography-helpers/) in bulma have mobile friendly alternatives though.
- some padding/margin needs to go , since the respective [helpers](https://bulma.io/documentation/helpers/spacing-helpers/) in bulma seem not to have mobile equivalents we need to customize this
- notbook output is not mobile friendly. This [post](https://blog.derlin.ch/share-your-jupyter-notebooks-like-a-pro#heading-using-nbconvert) has some pointers.

Start by reviewing the Bulma typography and spacing helper links, then inspect how notebook output is rendered in the blog. Define responsive behavior for text, spacing, and notebook output across mobile widths. Done means the blog remains readable and usable on mobile screens, including rendered notebook content.

Written by the indexing model from the issue text.