Update app.py

app.py

@@ -30,7 +30,6 @@ else:
     st.warning("⚠️ GROQ_API_KEY not found. Please add it to Hugging Face secrets.")
 
 # ---------------- STREAMLIT UI SETUP ----------------
-# CHANGED: Added initial_sidebar_state="expanded" to ensure it starts open
 st.set_page_config(
     page_title="PDF Assistant", 
     page_icon="📘", 
@@ -56,7 +55,6 @@ footer {
     display: none;
 }
 
-/* --- NEW CODE START: HIDE SIDEBAR TOGGLE BUTTONS --- */
 /* Hide the 'Close Sidebar' (<<) button inside the sidebar */
 section[data-testid="stSidebar"] > div > div:first-child {
     display: none;
@@ -65,7 +63,6 @@ section[data-testid="stSidebar"] > div > div:first-child {
 [data-testid="collapsedControl"] {
     display: none;
 }
-/* --- NEW CODE END --- */
 
 /* 3. SIDEBAR STYLING (INDEPENDENT LEFT PANEL SCROLL) */
 [data-testid="stSidebar"] {
@@ -92,7 +89,7 @@ section[data-testid="stSidebar"] > div > div:first-child {
     left: 0;
     width: 100%;
     height: 6rem;
-    background-color: #0e1117; 
+    background-color: #0e1117; /* Hardcoded Dark Background */
     z-index: 99998;
     display: flex;
     flex-direction: column;
@@ -160,11 +157,13 @@ section[data-testid="stFileUploader"] small {
 }
 
 /* 9. TITLE TEXT */
+/* UPDATED: Added color: #ffffff to ensure visibility on the dark header in Light Mode */
 .title-text {
     font-size: 2.5rem;
     font-weight: 800;
     margin: 0;
     line-height: 1.2;
+    color: #ffffff !important; 
 }
 .creator-text {
     font-size: 1rem;
@@ -181,6 +180,21 @@ section[data-testid="stFileUploader"] small {
     border: none;
     padding: 0;
 }
+
+/* --- NEW: FIX FOR CHAT BUTTON IN LIGHT MODE --- */
+/* If browser is in light mode, force the chat button to look clean (White bg, Dark text) */
+@media (prefers-color-scheme: light) {
+    [data-testid="stFormSubmitButton"] > button {
+        background-color: #ffffff !important;
+        color: #000000 !important;
+        border: 1px solid #e2e8f0 !important;
+    }
+    [data-testid="stFormSubmitButton"] > button:hover {
+        background-color: #f7fafc !important;
+        border-color: #cbd5e0 !important;
+        color: #000000 !important;
+    }
+}
 </style>
 """, unsafe_allow_html=True)