Feature request: Improve colour contrast in the tutorial pages.

[Geerayef]

Hello!

I'm learning Svelte and going through the tutorial on your website - which is very nice, and Svelte is really cool as well.

Anyways, I'm colorblind, not completely, but enough to make some things more difficult on occasion.
So one thing that I struggle with are the colours that denote lines of code that should be deleted (red) and added (green) during the tutorial. Most recent example is in Part 3 / Loading data / Page data:

/// file: src/routes/blog/+page.svelte
+++<script>
	export let data;
</script>+++

<h1>blog</h1>

<ul>
---	<li><a href="/blog/one">one</a></li>
	<li><a href="/blog/two">two</a></li>
	<li><a href="/blog/three">three</a></li>---
+++	{#each data.summaries as { slug, title }}
		<li><a href="/blog/{slug}">{title}</a></li>
	{/each}+++
</ul>

It took me a solid 10-15 minutes to figure out what the deal was here and why the code in the file didn't match the code in the explanation snippets, and then upon inspecting the page here on Github I figured it out.

Anyways, this is all just to give context to the main point that I'm attempting to spit out here.
It would be lovely if the contrast between the background and the foreground colours, and amongst the foreground colours themselves, was a tad bit greater.
Perhaps making the background darker and the foreground colours more bright and vibrant could help? Of course, I wish not to take away from the colorscheme of the Svelte website, but increasing contrast might help with readability.

Either way, thank you for the awesome website and I hope that my suggestion is constructive.