Space between architectural elements

Puget _____; sight from Tacoma

Software that runs ... well, everything

Atop

Sleep stage

Everyone's favorite meta moment

One you've broken up with

"Hey, you!" (esp. within range of Bows Bells)

Final meas. after subtracting tare (... or a salamander that's been injected with caffeine?)

Aromatic evergreen tree the leafs of which are used in cooking. [Post-script: I made clues for the down clues for the letters with no cross-clues, but I completely forget to do the same for the across clues.... Okay, the single isolated letter of 18A is a grade you get for the effort of trying. The letter of 1A is a curve that may send you flying. Together they make by all accounts, a two letter word for comparing equal amounts.]

Fragrant flower

Pleasant prefix

Highest-ranking officer of the United States Navy

Useful name for palindromes

Inset waterway [There are two letters with no cross clues. That's not very fair. So a clue for just those two letters: Prez between WMc and WT

Reddish-brown horse. [There are two letters with no cross clues. That's not very fair. So a clue for just those two letters: Concerning (abbr.)]

List of options

Cry at the sky as a dog

One who is more likely to remember Thundercats rather than either Rocky and Bullwinkle or Spongebob Squarepants

Atomic number 52