replace orphaned tailwind classes with project CSS

auth pages (login, registration, confirmation, recover) now use
setup-page/setup-header/admin-btn-block. theme toggle indicator
gets proper CSS. cleaned up dead h-full, size-3.5, ml-2 classes.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/berrypod_web/live/auth/confirmation.ex

@@ -7,8 +7,8 @@ defmodule BerrypodWeb.Auth.Confirmation do
   def render(assigns) do
     ~H"""
     <Layouts.app flash={@flash} current_scope={@current_scope}>
-      <div class="mx-auto max-w-sm">
-        <div class="text-center">
+      <div class="setup-page">
+        <div class="setup-header">
           <.header>Welcome {@user.email}</.header>
         </div>
 
@@ -27,11 +27,11 @@ defmodule BerrypodWeb.Auth.Confirmation do
             value="true"
             phx-disable-with="Confirming..."
             variant="primary"
-            class="w-full"
+            class="admin-btn-block"
           >
             Confirm and stay logged in
           </.button>
-          <.button phx-disable-with="Confirming..." class="w-full mt-2">
+          <.button phx-disable-with="Confirming..." class="admin-btn-block">
             Confirm and log in only this time
           </.button>
         </.form>
@@ -47,7 +47,7 @@ defmodule BerrypodWeb.Auth.Confirmation do
         >
           <input type="hidden" name={@form[:token].name} value={@form[:token].value} />
           <%= if @current_scope do %>
-            <.button phx-disable-with="Logging in..." variant="primary" class="w-full">
+            <.button phx-disable-with="Logging in..." variant="primary" class="admin-btn-block">
               Log in
             </.button>
           <% else %>
@@ -56,19 +56,19 @@ defmodule BerrypodWeb.Auth.Confirmation do
               value="true"
               phx-disable-with="Logging in..."
               variant="primary"
-              class="w-full"
+              class="admin-btn-block"
             >
               Keep me logged in on this device
             </.button>
-            <.button phx-disable-with="Logging in..." class="w-full mt-2">
+            <.button phx-disable-with="Logging in..." class="admin-btn-block">
               Log me in only this time
             </.button>
           <% end %>
         </.form>
 
-        <p :if={!@user.confirmed_at} class="admin-alert admin-alert-outline mt-8">
+        <div :if={!@user.confirmed_at} class="admin-alert admin-alert-outline">
           Tip: If you prefer passwords, you can enable them in the user settings.
-        </p>
+        </div>
       </div>
     </Layouts.app>
     """