diff --git a/poc4_active_source_20260714/src/poc4/hmm_ui.py b/poc4_active_source_20260714/src/poc4/hmm_ui.py
index 3cb6479..789228e 100644
--- a/poc4_active_source_20260714/src/poc4/hmm_ui.py
+++ b/poc4_active_source_20260714/src/poc4/hmm_ui.py
@@ -2,9 +2,13 @@
 
 HMM_CLEAN_THEME_CSS = """
 <style>
-:root { --hmm-navy:#003b70; --hmm-ink:#172b3a; --hmm-muted:#667785; --hmm-line:#dfe7ed; }
+:root {
+  color-scheme:light !important;
+  --hmm-navy:#003b70; --hmm-ink:#172b3a; --hmm-muted:#667785; --hmm-line:#dfe7ed;
+}
 html, body, [data-testid="stAppViewContainer"], .stApp {
   background:#fff !important; color:var(--hmm-ink) !important;
+  color-scheme:light !important;
   font-family:"Noto Sans KR","Malgun Gothic",sans-serif;
 }
  [data-testid="stAppViewContainer"] p,