Misc · Asking and learning: a poll, a survey, a quiz and flashcards

misc::Poll turns to results once the owner holds the vote, with Change
vote on Vote's stop. misc::Survey asks on one page and sends when each
question is answered, thanking in Submit's place and focus. misc::Quiz
checks, goes on, scores and starts again on one button. misc::Flashcards
turn on a press and go round the deck, each face fading in.

src/theme/misc.rs

@@ -9,6 +9,8 @@ pub struct MiscSizes {
     pub face: Rems,
     /// A world clock row's face.
     pub small_face: Rems,
+    /// A flashcard's least height.
+    pub card: Rems,
 }
 
 impl Theme {
@@ -16,6 +18,7 @@ impl Theme {
         MiscSizes {
             face: px_to_rems(112.0),
             small_face: px_to_rems(32.0),
+            card: px_to_rems(176.0),
         }
     }
 }