Update nightmode.css

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Merge pull request #1764 from Igglyboo/master

fix for issue #1760 - hitting enter in captcha field on FF will bring up big editor
Add type="button" to buttons
Merge pull request #1765 from mc10/buttons

Add type="button" to buttons
Merge pull request #1763 from gavin19/master

Update nightmode.css
fixes #1766 seems like youtube start time support already existed but it had an improper regex or yt changed their start time format