diff --git a/A00_Common/app_shell.ts b/A00_Common/app_shell.ts
index 06db1bfe5..018c26a4e 100644
--- a/A00_Common/app_shell.ts
+++ b/A00_Common/app_shell.ts
@@ -493,7 +493,8 @@ html:is([data-burger="on"], .is-bm-route) .app-burger { display: inline-flex; }
 .app-drawer__site { display: block; }
 .app-drawer__site > summary { min-height: var(--spacing-40); display: flex; align-items: center; padding-left: 16px; cursor: pointer; font-weight: 600; }
 .app-drawer__site > nav { margin-top: var(--spacing-8); }
-.app-drawer__steps .ui-workflow-layout__step { min-height: var(--spacing-40); margin-inline: 8px; width: auto; padding-left: 7px; }
+.app-drawer__steps .ui-workflow-layout__steps.is-vertical .ui-workflow-layout__step { min-height: var(--spacing-40); margin-inline: 8px; width: auto; padding-left: 7px; }
+.app-drawer :is(.ui-btn__label, .ui-workflow-layout__step-label) { min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
 .app-drawer__steps .ui-workflow-layout__step--home { margin-bottom: 0; }
 html[data-touch="on"] :is(.app-drawer__nav > *, .app-drawer__site > summary, .app-drawer__steps .ui-workflow-layout__step, .app-drawer__row > *) { min-height: 44px; }
 .app-drawer__row {
diff --git a/resources/tester/test_device_drawer.py b/resources/tester/test_device_drawer.py
index 0720e7706..790ca8e01 100644
--- a/resources/tester/test_device_drawer.py
+++ b/resources/tester/test_device_drawer.py
@@ -193,6 +193,12 @@ def test_352_4_burger_in_panel_title_row_text():
         in shell.split("html.is-bm-route .app-drawer__brand {", 1)[1]
     )
     assert "align-self: flex-end" not in shell
+    # 437-1: 진행 단계 단추 = 서랍 안쪽 폭(is-vertical width:100% 를 이기는 선택자) · 긴 글 줄임표
+    assert (
+        ".app-drawer__steps .ui-workflow-layout__steps.is-vertical .ui-workflow-layout__step {"
+        in shell
+    )
+    assert "text-overflow: ellipsis;" in shell.split(".app-drawer :is(.ui-btn__label", 1)[1]
     # 378-1: 프로젝트 화면 서랍 오른쪽 가장자리 = 강조색 2 px
     assert "border-right: 2px solid var(--color-accent);" in shell
     overlay = (root / "ui_template/ui_template_overlay.css").read_text(encoding="utf-8")