Fix minor frontend issues

frontend/src/components/HallSelector.tsx

@@ -1,4 +1,4 @@
-import { useMemo, useRef, useState } from 'react';
+import { useMemo, useRef, useState, useEffect } from 'react';
 import { useDispatch, useSelector } from 'react-redux';
 import { RootState } from '../store/store';
 import { setSelectedHall } from '../store/hallsSlice';
@@ -18,6 +18,12 @@ const HallSelector = () => {
     return Array.from(hallSet).sort();
   }, [contest.teams]);
 
+  useEffect(() => {
+    if (selectedHall && !halls.includes(selectedHall)) {
+      dispatch(setSelectedHall(null));
+    }
+  }, [halls, selectedHall, dispatch]);
+
   if (halls.length === 0) return null;
 
   const handleSelect = (hall: string | null) => {

frontend/src/index.css

@@ -29,6 +29,7 @@ body {
 
 nav>*,
 footer>* {
+  display: inline-block;
   margin-right: 1em;
 }