diff --git a/app/views/admin/invites/_invite.html.haml b/app/views/admin/invites/_invite.html.haml
index e3e5d32542..fcaf5fc616 100644
--- a/app/views/admin/invites/_invite.html.haml
+++ b/app/views/admin/invites/_invite.html.haml
@@ -3,7 +3,7 @@
     .input-copy
       .input-copy__wrapper
         = copyable_input value: public_invite_url(invite_code: invite.code)
-      %button{ type: :button }= t('generic.copy')
+      %button.button{ type: :button }= t('generic.copy')
 
   %td
     .name-tag
diff --git a/app/views/invites/_invite.html.haml b/app/views/invites/_invite.html.haml
index 7c94062de4..88479c4cad 100644
--- a/app/views/invites/_invite.html.haml
+++ b/app/views/invites/_invite.html.haml
@@ -3,7 +3,7 @@
     .input-copy
       .input-copy__wrapper
         = copyable_input value: public_invite_url(invite_code: invite.code)
-      %button{ type: :button }= t('generic.copy')
+      %button.button{ type: :button }= t('generic.copy')
 
   - if invite.valid_for_use?
     %td
diff --git a/app/views/mail_subscriptions/show.html.haml b/app/views/mail_subscriptions/show.html.haml
index a09dacc4d3..78de486457 100644
--- a/app/views/mail_subscriptions/show.html.haml
+++ b/app/views/mail_subscriptions/show.html.haml
@@ -16,4 +16,5 @@
     = form.hidden_field :type,
                         value: params[:type]
     = form.button t('mail_subscriptions.unsubscribe.action'),
-                  type: :submit
+                  type: :submit,
+                  class: 'btn'
diff --git a/app/views/oauth/authorizations/new.html.haml b/app/views/oauth/authorizations/new.html.haml
index ca9d12a676..17228d3cae 100644
--- a/app/views/oauth/authorizations/new.html.haml
+++ b/app/views/oauth/authorizations/new.html.haml
@@ -35,7 +35,8 @@
         = form.hidden_field :scope,
                             value: @pre_auth.scope
         = form.button t('doorkeeper.authorizations.buttons.authorize'),
-                      type: :submit
+                      type: :submit,
+                      class: 'btn'
 
       = form_with url: oauth_authorization_path, method: :delete do |form|
         = form.hidden_field :client_id,
@@ -52,4 +53,4 @@
                             value: @pre_auth.scope
         = form.button t('doorkeeper.authorizations.buttons.deny'),
                       type: :submit,
-                      class: 'negative'
+                      class: 'btn negative'
diff --git a/app/views/oauth/authorizations/show.html.haml b/app/views/oauth/authorizations/show.html.haml
index bdff336368..f014a1052f 100644
--- a/app/views/oauth/authorizations/show.html.haml
+++ b/app/views/oauth/authorizations/show.html.haml
@@ -4,4 +4,4 @@
     .input-copy
       .input-copy__wrapper
         = copyable_input value: params[:code], class: 'oauth-code'
-      %button{ type: :button }= t('generic.copy')
+      %button.button{ type: :button }= t('generic.copy')
diff --git a/app/views/settings/verifications/show.html.haml b/app/views/settings/verifications/show.html.haml
index c569843793..0243e3b806 100644
--- a/app/views/settings/verifications/show.html.haml
+++ b/app/views/settings/verifications/show.html.haml
@@ -17,7 +17,7 @@
   .input-copy.lead
     .input-copy__wrapper
       = copyable_input value: link_to('Mastodon', ActivityPub::TagManager.instance.url_for(@account), rel: :me)
-    %button{ type: :button }= t('generic.copy')
+    %button.button{ type: :button }= t('generic.copy')
 
   %p.lead= t('verification.extra_instructions_html')
 
@@ -60,7 +60,7 @@
   .input-copy.lead
     .input-copy__wrapper
       = copyable_input value: tag.meta(name: 'fediverse:creator', content: "@#{@account.local_username_and_domain}")
-    %button{ type: :button }= t('generic.copy')
+    %button.button{ type: :button }= t('generic.copy')
 
   %p.lead= t('author_attribution.then_instructions')