If you mean you would like it to "look" like the one here, it's just a matter of using a template with the proper styling.

If you don't know how to do that yourself, you might want to consider posting a job offer on the job board.

Dear sir,

I like the theme (fundamental) that I use for my test website. Actually I am very happy with it.
As far as I am good informed is the CSS leading for the style of the website.
So perhaps I should not consider changing it.

Actually is the 'look' of the search field not the biggest issue but more the way C5 and the themes are giving (or not giving) freedom to change header area's ...
In my case there is in the fundamental theme just above the navigation area a branding area which divides the width of the header in 2 areas. Putting the search block in the right area gives a half page broad search field ... and that is what actually I would like to change.
And it is not possible to bring in a new layout (which I could divide f.e. in 2 parts) in that branding area so it is also not possible to make the search block shorter.

So I thought lets look if there are other 'shorter' and more often used search blocks available in C5.

In my actual website I don't have even a search option, so it is not a major issue. But I like to make things better and bring my website to a more professional level. So a search field for songs or phrases or words is nice (also handy for my self) ...
And with the free add on that I have now installed it is working correct.

I was used to use 'iblox' website builder where I had more or less an empty sheet in front of me where I could drag and drop, move and change as much and as small or big as I wanted. I can understand that for 'responsive' purposes blocks and areas are needed. But now and then it feels very tightened that I can't change or move area's ...

And since I am not a programmer (a touring artist) it is often a matter of looking for compromises what is working and affordable.

Wordpress is still not in my mind. But there are in C5 so less add-on's available (compared with Wordpress) that I sometimes consider to migrate.

It became nowadays (compared with 10 years ago) not much easier to make choices: , make your own website with open source , or cms systems like weebly, motocms, etc etc

So I am in the middle of a finding out process but step by step C5 work out ... but I am not yet there where I want to be.

Any way, I hope I did not took too much of your time.