Improve collapse/expand feature

[jeroenheijmans]

The problem

There's a toggle button at the top-right of each block like this:

This feature is nice, but there are a few problems with this:

• It's not very discoverable
• The button has no clear affordance
• The button is repeated for each block, but any one of them toggles collapse/expand for all blocks
• The ARIA attributes for explaining the collapsed or expanded state are missing

Surely there's multiple ways to improve this?

PS. This came out of #69 and offline discussions with @dirkinfi (who personally also prefers to see a collapsed version by default).

[jeroenheijmans]

Proposed solution

One way to improve this situation is:

• remove the individual buttons, and instead making it a page-level toggle
• toggle could be placed in the header, near the Language switch (and the light/dark mode switch which is in progress in #33)
• toggle could also cause an update to the query or hash part of the URL, to allow hotlinking to a collapsed or expanded version
• toggle could be persisted in e.g. localStorage
• toggle could get a more clear affordance in this area as well

Personally I think it's all upsides and no down sides. Curious to hear other people's thoughts?

[dirkinfi]

I don't have time nor mental space to process this. I'd need to see this work. But anything is an improvement to the current functionality I guess ;-)