Errata: At 8:55pm EST 01/12/2018, the clue “Expectant Mother (2 words)” was changed to “Expectant mother (2 words)”.

These tunnels are so confusing - it’s too dark to see and the intersections are often framed in surprising ways. I wonder about the areas outside the tunnels.
7. Expectant mother (2 words)
8. Stylishly luxurious
10. Not near
12. Apropos superhero
14. Animal-filled attraction
15. Proteges and Tributes
17. Leftover or bonus
18. It may be criminal or supreme
19. Apropos Enterprise officer (last name)
23. Measure of distance or beer
24. Apropos rock opera character
25. Affirmative
26. Riceless preparation of 27-Across
27. Gold or cat, for example
1. Container for three men
2. Positions in the armed forces
3. You and I
4. One who plays CDs
5. Zags’ partner
6. TV sports award
9. Like some TVs before 4K
10. Came into bloom
11. “I do,” for example
13. Vertical line on a toggle switch
15. Violent chaos
16. Personal icon, online
19. Guitar predecessor
20. Slight advantage, or where your answer lies
21. Wise bird
22. Egg cells