This isn't even a valid example of DRYness; you're repeating yourself in your markup heavily to avoid it in your CSS. I hate to imagine <a href="..." class="body-link brand-color-link hover-underline undecorated-link">...</a> every time I want to make a link.
I played around with implementing something like this on linux (with xmodmap specifically) and didn't find anything conditional. I did figure out how to make holding right shift and tapping left produce a left parenthesis, and vice versa produce a right.
This is from memory, so bear with me if its not perfect, but I setup xmodmap with
Xmodmap allows you to define multiple symbols for a key. The first symbol is what you get with no modifiers; the second is with shift; the third is with Mode_switch (or AltGr, depending) and the fourth is with Shift and AltGr. There's sometimes although a 5-8, but that varies by platform and I haven't done enough experiments to really nail down what those are for linux these days, OR if those are tied to mod1/mod2/etc. instead of shift/altgr/mode_switch or specific modifiers like that.
Anyway, all the keysyms always defined the first three anyway (no modifiers, shift, and Mode_switch) and some defined the fourth. I don't have or use a Mode_switch key (yet) but I may try that out as a 'Greek' key or such, but since 90% of the time I'm programming I'm not sure if I'd ever use it.
My lines above defines parenleft as the symbol to send if key 50 (the left shift key) is pressed while the shift modifier is active. So, I can use the right shift to turn on the shift modifier, and then left shift turns into a left parenthesis key. Similarily, I can use the left shift key to turn the right shift into a right parenthesis.
So, to type a pair of parenthesis back to back "()" I press right shift, press left shift, release right shift, and tap right shift. It's certainly more awkward than what Steve was able to setup, but hey, its where I've got so far.
I'd say a far better layout than HHKB is the KBC Poker.
By holding the Fn key, it changes WASD into the arrow keys; a much more familiar layout to anyone who has ever played a game on a computer. There's also a hotkey to switch right shift, right alt, right menu, and right ctrl into up/left/down/right respectively. This again, I think makes perfect sense for the few situations you might want to be able to single press arrow keys. It also supports this sort of toggle for switching escape and tilde, which is very friendly for anyone who hits escape more often than tilde (probably almost everyone.) It also has things like volume control media keys via the Fn key that I don't believe any HHKB has.
