diff --git a/ai-web-agent-console/ai_web_agent_console/presentation.py b/ai-web-agent-console/ai_web_agent_console/presentation.py
index 14bfecf..4f1759f 100644
--- a/ai-web-agent-console/ai_web_agent_console/presentation.py
+++ b/ai-web-agent-console/ai_web_agent_console/presentation.py
@@ -58,6 +58,13 @@ def apply_console_theme(st: Any, profile: AppProfile) -> None:
         div[data-testid="stChatMessage"] [data-testid="stCaptionContainer"] * {{
           color:var(--console-text) !important;
           -webkit-text-fill-color:var(--console-text) !important; }}
+        /* Streamlit expanders use a dark summary bar in dark browser themes. */
+        details, details > summary {{
+          background:#fff !important; color:var(--console-text) !important;
+          border-color:var(--console-border) !important; color-scheme:light !important; }}
+        details > summary *, details > summary::marker {{
+          color:var(--console-text) !important;
+          -webkit-text-fill-color:var(--console-text) !important; }}
         div[data-testid="stButton"] > button, div[data-testid="stFormSubmitButton"] > button {{
           background:#fff !important; color:var(--console-text) !important;
           -webkit-text-fill-color:var(--console-text) !important;