First of all, I couldn't access the links you provided, which could be due to filtering or other restrictions. However, thank you for sharing some of your code so I can help answer the question.
Secondly, if this is a result of self-study, well done and keep up the good work. But if this is from a course, then the teacher should be held accountable!
My friend, avoid using positions for every element as it's usually unnecessary and can cause issues like these.
The main issue here is that you're pushing your elements offscreen, making them invisible but still present in the layout. You might see empty space on the screen and think it's actually empty, when it's not.
Since you mentioned you're learning web design, let me give you a lifesaving tip for your career: use positions only when absolutely necessary to maintain the natural flow of your page. Don't try to fit elements onto the screen like puzzle pieces or you'll encounter problems and struggle with responsiveness.
Specifically, use position absolute sparingly (position relative is much easier to work with). Use positions for overlapping elements, sticking one element to another, or keeping elements fixed on the viewport occasionally.
While there are more use cases for positions, it's best to avoid using them unless you have experience and know exactly when they're needed.
Also, remember that using large numeric values for margins, paddings, left, right, etc. (more than 100px) is usually a sign of error. Using over 500px indicates a significant mistake, and you should consider alternative solutions like float, flexbox, or grid layouts.
Best of luck!