This website!
Personal project
The website you're currently looking at was built from the ground up by me, using HTML, CSS, and a little bit of PHP. Over the years it has gone through several iterations where I continuously applied new techniques I had learned.
The site is fully responsive with several breakpoints that restructure the content for tablet and mobile. I use PHP includes to load common components such as navigation from a central file in a modular way, I used a CDN to offer images in the most suitable format and resolution, and cache elements that change infrequently to speed up loading. As a result, the site has a score of 98% in Google PageSpeed Insights, which looks at speed, accessibility, SEO, and more.
On top of that, the site has a dark mode that responds to the user's system setting, and the content is available in two languages