Unify segmented selectors and fix compact panel spacing

src/ui/styles/street-level.css

@@ -222,14 +222,6 @@ html:not([lang='en']) .sl-meta-row .sl-nearest-btn {
   flex-wrap: wrap;
 }
 
-/* No overflow clipping: it would cut off the buttons' focus ring. The end
-   buttons round themselves instead. */
-.sl-seg {
-  display: inline-flex;
-  border: 1px solid var(--glass-border-hover);
-  border-radius: 999px;
-}
-
 .sl-seg[hidden],
 .sl-controls[hidden],
 .sl-filters[hidden],
@@ -237,40 +229,6 @@ html:not([lang='en']) .sl-meta-row .sl-nearest-btn {
   display: none;
 }
 
-.sl-seg-btn {
-  font-family: var(--font-mono);
-  font-size: var(--sl-text);
-  letter-spacing: 0.08em;
-  padding: 4px 9px;
-  border: 0;
-  background: transparent;
-  color: var(--text-secondary);
-  cursor: pointer;
-}
-
-.sl-seg-btn:first-child {
-  border-radius: 999px 0 0 999px;
-}
-
-.sl-seg-btn:last-child {
-  border-radius: 0 999px 999px 0;
-}
-
-.sl-seg-btn + .sl-seg-btn {
-  border-left: 1px solid var(--glass-border);
-}
-
-.sl-seg-btn:focus-visible {
-  position: relative;
-  outline: 1px solid var(--accent);
-  outline-offset: 2px;
-}
-
-.sl-seg-btn.is-active {
-  background: rgba(5, 203, 99, 0.22);
-  color: var(--text-primary);
-}
-
 .sl-since {
   display: grid;
   grid-template-columns: auto 1fr;