Improve FAQ & video rendering, tighten homepage and CSS

frontend/src/App.tsx

@@ -300,6 +300,7 @@ export default function App() {
         screenshotMode
         ogMode={isOgMode}
         initialTravelTime={urlState.travelTime}
+        shareCode={urlState.share}
       />
     );
   }
@@ -406,6 +407,7 @@ export default function App() {
           isMobile={isMobile}
           initialTravelTime={mapUrlState.travelTime}
           initialPostcode={mapUrlState.postcode}
+          shareCode={mapUrlState.share}
           user={user}
           onLoginClick={() => {
             setAuthModalTab('login');