[UI] Adjust description text and CSS styles

[vas3k]

• Updated description text on the main page to make it clearer to novice users what it is and what it can be used for
• Prettify CSS styles

TADA 🚀

[kirushik]

I'm not super-attached to my wording — but I'd still say that the general idea of a) printouts going into non-transparent envelopes and b) being distributed across multiple locations is something we'd better communicate explicitly.

I also miss my tagline ("Shamir Secret Sharing for people with friends") a bit — it also implied the same idea; but I would accept this not being aligned with the general style of our communication anymore.

[vas3k]

@kirushik

but I'd still say that the general idea of a) printouts going into non-transparent envelopes and b) being distributed across multiple locations is something we'd better communicate explicitly.

Good suggestion, commited

I also miss my tagline ("Shamir Secret Sharing for people with friends") a bit

I wanted to keep it, but it just didn't seem to fit the style of this How To. However, this tagline is still the description of the NPM package and will be visible to everyone who downloads and runs it :)

Please re-review