WebSIte design just html, css, no database, no user input.

Industry: Internet/Software
Kind of design: Single web page
Num. of web pages: 5
Description of every page: I did my own website.
It is a web site for a Qgis plugin. (software)
The actual site is https://fastversion.sourceforge.io/, and the text and videos are the same that will be used in the new site.
I would like to change it “completely”, mainly the design of the front page, and the organization so that the “user guide” page is not in a single page.
So is not only the design of the pages, but also a graphical design of the main page title “FastVersion” with characters as Logo, and white background.
The site must be in simple HTML, doesn’t need to have database access, buttons, etc. Just the Html and design, styling.
The videos showed in https://fastversion.sourceforge.io/ are the same, and stored in YouTube.
Ideas for the visual style: Clear modern design, no childish
Things to avoid: No CMS or Frameworks just HTML
Website url: https://fastversion.sourceforge.io/
Website information: QGis plugin
Urls to draw inspiration from: https://www.pitneybowes.com/us/location-intelligence/geographic-information-systems/mapinfo-pro.html
Extra notes: