Improve navbar button hierarchy and visual balance

## Is your feature request related to a problem? Please describe.

The navbar action buttons on the right side currently take too much horizontal space and have weak visual hierarchy. Star, Sponsor, and Sign In appear similarly prominent, which makes the header feel crowded and reduces clarity.

## Describe the solution you'd like

* Reduce the visual weight of secondary actions such as Star and Sponsor
* Give Sign In clearer visual priority
* Improve spacing and balance between the navbar action buttons
* Keep the overall layout unchanged while making the right side cleaner

## Describe alternatives you've considered

* Reducing the size of the search bar
* Changing the full navbar layout

However, improving only the button hierarchy was chosen as a smaller and more focused UI enhancement.

## Are you going to work on implementing this?

* [x] Yes
* [ ] No

## Additional context

I have already implemented a working version of this improvement and can provide before/after screenshots.