feat: improve templates

public/oidcerror.tmpl

@@ -1,9 +1,12 @@
 <html>
     <head>
-
+        <!-- NOTE: You should definitely host this yourself! (and you can adjust the style that way, too!) -->
+        <link rel="stylesheet" href="https://cdn.jsdelir.net/gh/janishutz/oidclogin/public/style.css">
     </head>
     <body>
-        <h1>Login Failed!</h1>
-        <p>{{ .error }}</p>
+        <h1>500</h1>
+        <p>Login Failed!</p>
+        <a href="/">Back Home</a>
+        <p class="error-msg">{{ .error }}</p>
     </body>
 </html>