Slow loading speed on the top page

[taea]

I think we could improve the loading time on the top page to make it faster.
As the designer, I have several ideas.

Improvement measures under consideration

I'm thinking it would be good to try these out in order from top to bottom in the future:

1. I think we can make the SVG illustrations much lighter, so I'd like to try that
2. In some areas, converting from SVG to PNG or similar formats might result in lighter file sizes
3. In the future, making the illustrations a bit smaller and creating a cleaner layout could give a more elegant atmosphere, and it might also create a layout that matches better when the Code Example supports WASM (Make runnable code example with WASM #3719)