diff --git a/app/assets/stylesheets/atoms/_a-button.sass b/app/assets/stylesheets/atoms/_a-button.sass
index cb9ce775f6a..45764cd3e8b 100644
--- a/app/assets/stylesheets/atoms/_a-button.sass
+++ b/app/assets/stylesheets/atoms/_a-button.sass
@@ -83,6 +83,15 @@
       input[type="submit"]
         padding-right: 2.25em
 
+  //icon
+  &.is-back
+    +position(relative)
+    +padding(horizontal, .75em 0)
+    &::before
+      +fa(fas '\f104')
+      +position(absolute, left .75em, top 50%)
+      transform: translate(0, -50%)
+
 
 input[type="submit"],
 input[type="reset"],
diff --git a/app/assets/stylesheets/blocks/event/_event-meta.sass b/app/assets/stylesheets/blocks/event/_event-meta.sass
index 0b764398fc5..b887e4fdcda 100644
--- a/app/assets/stylesheets/blocks/event/_event-meta.sass
+++ b/app/assets/stylesheets/blocks/event/_event-meta.sass
@@ -39,7 +39,7 @@
   +media-breakpoint-up(md)
     display: flex
     align-items: center
-  a
+  a:not(.a-button)
     +default-link
     +hover-link-reversal
 
diff --git a/app/assets/stylesheets/blocks/page/_page-header-actions.sass b/app/assets/stylesheets/blocks/page/_page-header-actions.sass
index 73e9db3aff9..d84b130fee0 100644
--- a/app/assets/stylesheets/blocks/page/_page-header-actions.sass
+++ b/app/assets/stylesheets/blocks/page/_page-header-actions.sass
@@ -25,10 +25,3 @@
   .a-button
     +media-breakpoint-up(md)
       height: 2.125rem
-    &.is-back
-      +position(relative)
-      +padding(horizontal, .75em 0)
-      &::before
-        +fa(fas '\f104')
-        +position(absolute, left .75em, top 50%)
-        transform: translate(0, -50%)
diff --git a/app/assets/stylesheets/blocks/thread/_thread-comments.sass b/app/assets/stylesheets/blocks/thread/_thread-comments.sass
index b7a1011d7d4..0bbe75d9f64 100644
--- a/app/assets/stylesheets/blocks/thread/_thread-comments.sass
+++ b/app/assets/stylesheets/blocks/thread/_thread-comments.sass
@@ -22,9 +22,6 @@
   +media-breakpoint-down(sm)
     display: none
 
-.thread-comment__user-icon
-  +size(3.5rem)
-
 .thread-comment__title
   width: 100%
   +text-block(.875rem 1.4, 600)
@@ -103,7 +100,8 @@
       align-self: flex-end
 
 .thread-comment__user-icon
-  +size(2.75rem auto)
+  +size(3.5rem)
+  object-fit: cover
   border-radius: 50%
   +position(absolute, left 0, top 0)
   +margin(vertical, .75rem)
diff --git a/app/views/generations/show.html.slim b/app/views/generations/show.html.slim
index 9640c614b9b..3ee4a3b2957 100644
--- a/app/views/generations/show.html.slim
+++ b/app/views/generations/show.html.slim
@@ -14,13 +14,15 @@ main.page-main
   header.page-main-header
     .container
       .page-main-header__inner
-        h1.page-main-header__title
-          = title
-        .page-header-actions
-          ul.page-header-actions__items
-            li.page-header-actions__item
-              = link_to generations_path, class: 'a-button is-md is-block is-secondary is-back' do
-                | 期一覧
+        .page-main-header__start
+          h1.page-main-header__title
+            = title
+        .page-main-header__end
+          .page-main-header-actions
+            ul.page-main-header-actions__items
+              li.page-main-header-actions__item
+                = link_to generations_path, class: 'a-button is-sm is-block is-secondary is-back' do
+                  | 期一覧
 
   .page-body
     .container