tooltips and accordions

tooltips — a non-interactive box that pops up

There isn't an easy, straightforward way to do tooltips yet, even though it's the year of our lord 2025.   (though maybe there's a dead-simple library out there that I haven't found yet)

Don't get lost in the weeds, because this section is minutiae rather than a solution. However, here are some small aspects to consider:

• CSS anchor may make pure-CSS possible. It just currently isn't supported in Firefox yet. (but it can be enabled)
• Accessibility really should be built-in. ARIA tags can be used to indicate to screen readers that certain bits are a tooltip. [1]

accordions — an interactive box that pops up

The modern no-Javascript way to do this is <details> and <summary>.

Another no-Javascript option is <dialog>.