Last stretch WHAT?

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Across
  1. 4. Marine bird native to the Pacific (3 words)
  2. 9. An essential part of any social media experience (2 words)
  3. 10. Small provincial town with very serious super market policies
  4. 11. One of the documents
  5. 13. A color.. straight out of a resolution
  6. 14. Just a local theater where couples fall in love
  7. 16. Hot London meeting place (2 words)
  8. 17. He is in charge of final touches (2 words)
  9. 18. One of the documents
  10. 19. Duchess of... better don't go late to THAT play!
  11. 21. Legendary spotify playlist
Down
  1. 1. cute and sexy rapper
  2. 2. The blues are likely on this day, but not necessarily (2 words)
  3. 3. 'Why not'... go for a drink? (3 words)
  4. 5. Mysterious neighbor and player (?) (2 words)
  5. 6. One of the documents
  6. 7. Drink this cocktail... at your own risk!
  7. 8. One of the documents (2 words)
  8. 12. A stand up, yet kind, sensation
  9. 15. Jean Paul... contradictory alter ego
  10. 20. Short for.. I Love you