Add styles for danger zone section

app/assets/stylesheets/settings.css

@@ -62,6 +62,16 @@
     }
   }
 
+  .settings__section--negative {
+    h2 {
+      color: var(--color-negative);
+    }
+
+    .divider {
+      --divider-color: oklch(var(--lch-red-light));
+    }
+  }
+
   .settings__section:has(.settings__scrollable-list) {
     @media (min-width: 640px) {
       display: flex;

app/views/account/settings/_cancellation.html.erb

@@ -1,7 +1,7 @@
 <% if Current.account.cancellable? && Current.user.owner? %>
-  <section class="settings__section">
+  <section class="settings__section settings__section--negative">
     <header>
-      <h2 class="divider txt-negative">Danger zone</h2>
+      <h2 class="divider">Danger zone</h2>
       <div>Permanently delete your account and all its data, including users, boards, and cards.</div>
     </header>