Adding dark mode

layout.py

@@ -1,9 +1,43 @@
 import streamlit as st
 
 def init_session_state():
-    if 'dark_mode' not in st.session_state:
-        st.session_state.dark_mode = False
-    if 'code' not in st.session_state:
-        st.session_state.code = ""
-    if 'stdin' not in st.session_state:
-        st.session_state.stdin = ""
+    st.session_state.setdefault("code", "")
+    st.session_state.setdefault("stdin", "")
+    st.session_state.setdefault("theme", "light")
+
+def apply_theme(theme):
+    LIGHT = {
+        "bg": "#f5f5f5",
+        "panel": "#ffffff",
+        "text": "#1a1a1a",
+        "border": "#dddddd"
+    }
+    DARK = {
+        "bg": "#0f1620",
+        "panel": "#1c2330",
+        "text": "#e3e8f1",
+        "border": "#2a3240"
+    }
+
+    colors = DARK if theme == "dark" else LIGHT
+
+    st.markdown(f"""
+    <style>
+        .stApp {{
+            background-color: {colors["bg"]};
+            color: {colors["text"]};
+        }}
+        [data-testid="stSidebar"] {{
+            background-color: {colors["panel"]} !important;
+        }}
+        textarea, input, .stTextArea textarea {{
+            background-color: {colors["panel"]} !important;
+            color: {colors["text"]} !important;
+            border: 1px solid {colors["border"]} !important;
+            border-radius: 4px !important;
+        }}
+        label[data-testid="stMarkdownContainer"] > div > div {{
+            color: {colors["text"]} !important;
+        }}
+    </style>
+    """, unsafe_allow_html=True)