Top-margin causing interaction and interface issues

[zinzy]

Thanks for this lovely theme, @vhbelvadi! My colleague and I are quite the fans of it. We've noticed two small quirks.

.markdown-source-view.mod-cm6 .cm-line {
	margin-top: 0.1rem !important;
}

This style definition results in:

1. The user being unable to select words in the last line of a document (bar the very last word)
2. Separators between lines in a code block (I'm following Carbon design guidelines here to suggest this isn't strictly necessary)

I've already added this to my Obsidian snippets and I haven't noticed anything weird so far, so I went ahead and created a pull request as well.