ensure emulator warning text is accessible (#4868)

* ensure emulator warning text is accessible

the emulator warning text color does not have a sufficient contrast ratio to pass AA guidelines (4.5:1)

this fix provides a darker red color that achieves the AAA contrast ratio of 7:1

* Create fast-mangos-serve.md

* Update color in Auth Closure SDK.

* Update fast-mangos-serve.md

Co-authored-by: Yuchen Shi <[email protected]>

Author: markgoho

.changeset/fast-mangos-serve.md

@@ -0,0 +1,5 @@
+---
+"@firebase/auth": patch
+---
+
+Ensure emulator warning text is accessible.

packages-exp/auth-exp/src/core/auth/emulator.ts

@@ -122,7 +122,7 @@ function emitEmulatorWarning(disableBanner: boolean): void {
     sty.width = '100%';
     sty.backgroundColor = '#ffffff';
     sty.border = '.1em solid #000000';
-    sty.color = '#ff0000';
+    sty.color = '#b50000';
     sty.bottom = '0px';
     sty.left = '0px';
     sty.margin = '0px';

packages/auth/src/auth.js

@@ -339,7 +339,7 @@ fireauth.Auth.prototype.emitEmulatorWarning_ = function(disableBanner) {
       ele.style.width = '100%';
       ele.style.backgroundColor = '#ffffff';
       ele.style.border = '.1em solid #000000';
-      ele.style.color = '#ff0000';
+      ele.style.color = '#b50000';
       ele.style.bottom = '0px';
       ele.style.left = '0px';
       ele.style.margin = '0px';