chore: add background for the card

assets/scss/common/_custom.scss

@@ -869,10 +869,27 @@ $map-pulse-offsets:
 // separates the head from the list, and with a line already doing that the bold was a
 // second, louder way of saying it — on a 144px card that made the place name the loudest
 // thing in a panel that exists to show the people. Its position and the rule are enough.
+// A band, not a line of text with a rule under it: the tint runs out through the card's
+// own padding to both edges and takes the card's top corners, so the name reads as the
+// card's header.
+//
+// The map's own land, lightened — the card's header is the colour of the ground it sits
+// on, and the hairline under it is that same land at full strength. It was the warm tint
+// the project cards are filled with for a moment, and warm is what the marks are: a peach
+// strip on a card full of faces put a second accent colour a few pixels from the dots.
+// Grey leaves the dots and the row highlight as the only colour in the section.
+//
+// The negative margins are the card's padding exactly, and the band's own padding puts it
+// straight back, so the name still starts on the same vertical as the handles below it.
+// Radius is the card's less its 1px border, which is the inside of the corner the band
+// has to sit in. Nothing is clipped to get there — `overflow: hidden` on the card would
+// have taken the caret off with it.
 .worldmap-city-head {
-  margin: 0 0 0.4375rem;
-  padding-bottom: 0.4375rem;
+  margin: -0.625rem -0.6875rem 0.4375rem;
+  padding: 0.5rem 0.6875rem;
+  background: mix($map-land, #fff, 55%);
   border-bottom: 1px solid $map-land;
+  border-radius: calc(0.75rem - 1px) calc(0.75rem - 1px) 0 0;
   line-height: 1.3;
   // A hair of tracking on the one line that is a name rather than a handle, and the only
   // thing here that is read as words.