Resolve "Formularfelder haben im Hochkontrastmodus einen zu geringen Kontrast"

Closes #3866

Merge request studip/studip!2718

resources/assets/stylesheets/highcontrast.scss

@@ -1295,4 +1295,20 @@ button.as-link {
             }
         }
     }
-} 
+}
\ No newline at end of file
+form.default {
+    input[type=date],
+    input[type=datetime-local],
+    input[type=email],
+    input[type=number],
+    input[type=password],
+    input[type=tel],
+    input[type=text],
+    input[type=time],
+    input[type=url],
+    select,
+    textarea {
+        border: 1px solid var(--black);
+    }
+}
+