Improve login buttons (README)

[select]

Is your feature request related to a problem? Please describe.
The login button design could be a bit nicer.
In addition to that the code that was in the readme did not work for me

Describe the solution you'd like
You can toggle showing the login user/pw form with this code

Disclaimer

<form action="http://localhost:8096/sso/OID/start/keycloak">
  <button class="raised block emby-button button-submit">
    Sign in with SSO
  </button>
</form>
<input type="checkbox" id="show-login-form" /> 
<label for="show-login-form" class="raised block emby-button">Login with username and password</label>

Custom CSS

a.raised.emby-button {
  padding: 0.9em 1em;
  color: inherit !important;
  margin-top: 0.5rem;
}

.disclaimerContainer {
  display: block !important;
  width: auto !important;
  height: auto !important;
}
.manualLoginForm, .btnForgotPassword.btnForgotPassword, 
#show-login-form {
  display: none;
}
.readOnlyContent {
  display: flex;
  flex-direction: column-reverse;
}

.manualLoginForm:has(~ .readOnlyContent input[type=checkbox]:checked),
.btnForgotPassword:has(~ .disclaimerContainer input[type=checkbox]:checked) {
  display: block; 
}
.readOnlyContent:has(> .disclaimerContainer input[type=checkbox]:checked) {
  flex-direction: column;
}
.readOnlyContent input[type=checkbox]:checked ~ label {
  display: none;
}

Please consider that I had to add width and height to actually show the disclaimer

.disclaimerContainer {
  display: block !important;
  width: auto !important;
  height: auto !important;
}

[9p4]

I think it might be best to move this to a discussion? I may put together a document that details all the different methods of the custom login buttons.

[cybik]

For the record: I've wasted about an hour debugging this button, only to discover that adding it through the Disclaimer field trips uBlock Origin's "Cosmetic Filtering" detection. Either disabling Cosmetics, or adding your Jellyfin instance as a Trusted Site, is enough to clear this.