99puxwol5: Delete legacy.css and move its last rules into the component stylesheets

src/components/Composer.tsx

@@ -210,7 +210,7 @@ export function Composer({ value, busy, error, file = null, onChange, onFile, on
         </div>
       ) : null}
       {error ? (
-        <p className="error" role="alert">Publishing the post failed. Your text is still here.</p>
+        <p className="composer-error" role="alert">Publishing the post failed. Your text is still here.</p>
       ) : null}
       <div className="composer-bar">
         {onFile ? (

src/components/SignInForm.tsx

@@ -44,7 +44,7 @@ export function SignInForm({ onSignedIn }: { onSignedIn: (p: Person) => void })
         </div>
         <form className="signin-form" onSubmit={submit} noValidate>
           {error && (
-            <p role="alert" className="error signin-error">
+            <p role="alert" className="signin-error">
               {error}
             </p>
           )}