Nit: the tool-tips on the action icons in the top-right aren't consistent.

When music is playing the tool tip is "unmute" which is a verb. It should either be "mute" (to indicate what clicking will do) or "unmuted" (adjective) indicating the current state. Similarly, when the music is muted the tool-tip should either be "muted" or "unmute".

I'm not sure _which_ is wanted (verb or adjective) because the ruler tool-tip uses "Hide Ruler" and "Show Ruler" (verb), while the units tool-tip uses "Units: imperial" and "Units: Metric" (adjective). The info tool-tip ("Info") is also an adjective.

For consistency, I'd use a verb-phrase in all the tool tips:

- "Show info"

- "Switch units to metric/imperial"

- "Hide/show ruler"

- "Mute/unmute music"

I mean, I know this is pedantic nit-picking, but the site is so perfect, what else am I going to do?