Style "Log in with NeoPass" button to better match Neopets

Got the icon and background style from Neopets.com! I didn't quite copy
the whole button style, both because getting it to play nice with our
existing styles didn't *immediately* work, but also because I think
this works out as a really good compromise between our two styles
anyway!

app/assets/stylesheets/devise/sessions/new.sass

@@ -0,0 +1,17 @@
+body.devise-sessions, body.devise-sessions-new
+	.log-in-with-neopass-button
+		background: linear-gradient(#ebb233, #f6e250, #ebb233)
+		color: #111
+		font-size: 1rem
+		text-shadow: none
+		font-family: "Arial Black", sans-serif
+		margin-bottom: 1em
+
+		&:hover
+			color: #111 // override default DTI styles
+			filter: brightness(105%)
+
+		.neopass-icon
+			vertical-align: middle
+			height: 2em
+			width: 2em

app/views/devise/sessions/new.html.erb

@@ -1,15 +1,12 @@
 <h2>Log in</h2>
 
 <% if can_use_neopass %>
-  🌟✨🌟✨🌟✨🌟✨🌟
-  <br />
-  <%= button_to "Log in with NeoPass",
-                auth_user_neopass_omniauth_authorize_path(intent: "login"),
-                data: {turbo: false} # Turbo can't handle this redirect!
+  <%= button_to auth_user_neopass_omniauth_authorize_path(intent: "login"),
+                data: {turbo: false}, class: "log-in-with-neopass-button" do
   %>
-  🌟✨🌟✨🌟✨🌟✨🌟
-  <br />
-  <br />
+    Log in with
+    <%= image_tag "neopass_icon.png", alt: "NeoPass", class: "neopass-icon" %>
+  <% end %>
 <% end %>
 
 <%= form_for(resource, as: resource_name, url: session_path(resource_name)) do |f| %>
@@ -36,3 +33,7 @@
 <% end %>
 
 <%= render "devise/shared/links" %>
+
+<% content_for :stylesheets do %>
+  <%= stylesheet_link_tag "devise/sessions/new" %>
+<% end %>