Add theme support, light theme, and edgeless light

sass/includes/_settings-page.sass

@@ -0,0 +1,49 @@
+$_theme: () !default
+
+@use "sass:map"
+@use "forms" as forms
+
+.settings-page
+  padding: 40px 20px 20px
+  max-width: 600px
+  margin: 0 auto
+
+.save-settings
+  margin-top: 24px
+
+  .border-look
+    font-size: 22px
+    padding: 7px 16px 8px
+
+.more-settings-header
+  margin-top: 36px
+
+.more-settings
+  margin-top: 24px
+  padding: 12px
+  border: 1px solid map.get($_theme, "edge-grey")
+  border-radius: 8px
+  background-color: map.get($_theme, "bg-3")
+
+  &__list
+    margin: 0
+    padding-left: 1em
+    line-height: 1
+
+  &__list-item:not(:last-child)
+    margin-bottom: 0.4em // emulate line-height
+
+.data-management
+  margin-top: 24px
+
+  .delete-confirm-container
+    background: map.get($_theme, "bg-1")
+    margin-bottom: -36px
+
+@include forms.checkbox-hider("delete-confirm")
+
+#delete-confirm:not(:checked) ~ * #delete-button
+  visibility: hidden
+
+.delete-details[open]
+  padding-bottom: 40px