diff --git a/app/javascript/styles/mobile-small.scss b/app/javascript/styles/mobile-small.scss
new file mode 100644
index 0000000000000000000000000000000000000000..3569be3339bb7c4d964d5d1086c1efe69fa0cc1b
--- /dev/null
+++ b/app/javascript/styles/mobile-small.scss
@@ -0,0 +1,24 @@
+@import 'application';
+
+.columns-area--mobile {
+  .status {
+    &__content {
+      font-size: 13px;
+      line-height: 16px;
+    }
+    &__prepend {
+      font-size: 13px;
+    }
+  }
+  .display-name {
+    font-size: 13px;
+    &__account {
+      font-size: 13px;
+    }
+  }
+  .notification {
+    &__message {
+      font-size: 13px;
+    }
+  }
+}
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 835034b192782c02677e1eb9dadd6e7c11812d71..7ab08c21bffa7a0048d6031a259b2db7e2f51f9c 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -1257,6 +1257,7 @@ en:
     instance-ticker-type-2-light: Mastodon (Light / Instance Ticker Type-2 favicon v2)
     instance-ticker-type-2: Mastodon (Dark / Instance Ticker Type-2 favicon v2)
     mastodon-light: Mastodon (Light)
+    mobile-small: Mobile Small / Mastodon (Dark)
   time:
     formats:
       default: "%b %d, %Y, %H:%M"
diff --git a/config/locales/ja.yml b/config/locales/ja.yml
index adbb6c27056aaec0ba585e32df67f50b7df4c579..f34f60a759c6294de382c2abc71b4e1cd871c4c8 100644
--- a/config/locales/ja.yml
+++ b/config/locales/ja.yml
@@ -1221,6 +1221,7 @@ ja:
     instance-ticker-type-2-light: Mastodon (ライト / インスタンス・ティッカー Type-2 Favicon v2)
     instance-ticker-type-2: Mastodon (ダーク / インスタンス・ティッカー Type-2 Favicon v2)
     mastodon-light: Mastodon (ライト)
+    mobile-small: Mobile 小 / Mastodon (ダーク)
   time:
     formats:
       default: "%Y年%m月%d日 %H:%M"
diff --git a/config/themes.yml b/config/themes.yml
index 3b1f97cab3713e4015b9b4794ab02ebec8ccb85b..f0722df6a3a5e55620957cf051546248144ac808 100644
--- a/config/themes.yml
+++ b/config/themes.yml
@@ -1,6 +1,7 @@
 default: styles/application.scss
 contrast: styles/contrast.scss
 mastodon-light: styles/mastodon-light.scss
+mobile-small: styles/mobile-small.scss
 instance-ticker-type-0: styles/instance-ticker-type-0.scss
 instance-ticker-type-1: styles/instance-ticker-type-1.scss
 instance-ticker-type-2: styles/instance-ticker-type-2.scss