diff --git a/.streamlit/config.toml b/.streamlit/config.toml
index dfd04be..b239d66 100644
--- a/.streamlit/config.toml
+++ b/.streamlit/config.toml
@@ -14,12 +14,5 @@ hideWelcomeMessage = true
 toolbarMode = "viewer"
 showSidebarNavigation = false
 
-[theme]
-base="light"
-backgroundColor = "#eee"
-secondaryBackgroundColor = "#fff"
-primaryColor = "black"
-baseRadius = "none"
-
 [runner]
 magicEnabled = false
\ No newline at end of file
diff --git a/app/pages/settings.py b/app/pages/settings.py
index 6cb4b49..8db6912 100644
--- a/app/pages/settings.py
+++ b/app/pages/settings.py
@@ -1,17 +1,27 @@
 import streamlit as st
-from pandas.core.ops.docstrings import key
-from pandas.io.formats.style import Styler
 
 import queries.crud as crud
+import themes as th
 
 is_login_enabled = hasattr(st, 'user') and hasattr(st.user, 'is_logged_in')
 is_logged_in = is_login_enabled and st.user.is_logged_in
 
 st.title("Settings")
-
 if hasattr(st.session_state, 'user_name'):
     st.markdown(f"Currently logged in as **{st.session_state.user_name}**")
 
+
+st.header("Theme")
+themes = st.session_state.themes
+with st.container(horizontal=True, width="stretch"):
+    for theme in ["light", "dark"]:
+        if st.button(label=themes[theme]["button_face_label"],
+                 icon = themes[theme]["button_face_icon"],
+                 disabled = (theme == st.session_state.current_theme),
+                 width = "stretch"):
+            th.change_theme(theme)
+            st.rerun()
+
 st.header("Colors")
 with st.container(key="settings-color-selector"):
     palettes = crud.get_color_palettes()
diff --git a/app/queries/crud.py b/app/queries/crud.py
index 3db247b..e346f51 100644
--- a/app/queries/crud.py
+++ b/app/queries/crud.py
@@ -87,7 +87,7 @@ def get_color_palettes():
         return None
 
 
-def get_color_palette():
+def get_color_palette() -> int:
     user_id = int(st.session_state.user_id)
     try:
         return int(connection().query('SELECT color_palette_id FROM users WHERE id = :id''', params={'id': user_id})['color_palette_id'][0])
@@ -123,3 +123,26 @@ def get_colors():
     except Exception as e:
         logger.error(e)
         return None
+
+
+def set_theme(theme:str):
+    user_id = int(st.session_state.user_id)
+    logger.info("Changing theme for user %d to %s", user_id, theme)
+    with connection().session as session:
+        try:
+            query = text('UPDATE users SET theme = :theme WHERE id = :user')
+            session.execute(query, {
+                'theme': theme,
+                'user': user_id
+            })
+        except Exception as e:
+            logger.error(e)
+            session.rollback()
+
+def get_theme() -> str:
+    user_id = int(st.session_state.user_id)
+    try:
+        return connection().query('SELECT theme FROM users u WHERE u.id = :id', params={'id': user_id})['theme'][0]
+    except Exception as e:
+        logger.error(e)
+        return None
\ No newline at end of file
diff --git a/app/queries/user.py b/app/queries/user.py
index 8da0d1d..01bffbd 100644
--- a/app/queries/user.py
+++ b/app/queries/user.py
@@ -43,25 +43,27 @@ def create_user(email, name, oidc_user_id):
 
 
 def set_user_in_session(user: UserInfoProxy):
-    email = user.email
-    user_id = user.sub
-    if hasattr(user, 'name'):
-        name = user.name
-    else:
-        name = None
 
-    user_entity = find_user_by_oidc_id(user_id)
+    email = user.email if hasattr(user, "email") else None
+    user_id = user.sub if hasattr(user, "sub") else None
+    name = user.name if hasattr(user, "name") else None
+
+    user_entity = find_user_by_oidc_id(user_id) if user_id else st.dataframe()
     if user_entity.empty:
-        user_entity = find_user_by_email(email)
+        user_entity = find_user_by_email(email) if email else st.dataframe()
     if user_entity.empty:
         user_entity = find_default_user()
-        if user_entity.empty:
+        if user_entity.empty and email and name and user_id:
             user_entity = create_user(email, name, user_id)
-        else:
+        elif name:
             update_default_user(email, name, user_id)
             user_entity = find_user_by_oidc_id(user_id)
 
-    st.session_state.user_id = user_entity["id"][0]
-    st.session_state.user_name = user_entity["name"][0]
-    st.session_state.user_email = user_entity["email"][0]
-    st.session_state.user_external_id = user_entity["oidc_user_id"][0]
\ No newline at end of file
+    if not user_entity.empty:
+        st.session_state.user_id = user_entity["id"][0]
+        st.session_state.user_name = user_entity["name"][0]
+        st.session_state.user_email = user_entity["email"][0]
+        st.session_state.user_external_id = user_entity["oidc_user_id"][0]
+        st.session_state.current_theme = user_entity["theme"][0]
+    else:
+        logger.warn("No active user found!")
\ No newline at end of file
diff --git a/app/streamlit_app.py b/app/streamlit_app.py
index 1474b04..e58488c 100644
--- a/app/streamlit_app.py
+++ b/app/streamlit_app.py
@@ -5,10 +5,12 @@ import queries.user as user_queries
 from logger import init_logger
 from styles import init_styles
 from user import init_user, is_login_enabled, is_logged_in
+from themes import init_themes
 
 init_logger()
 init_user()
 init_styles()
+init_themes()
 
 if is_login_enabled and not is_logged_in:
     with st.container(width="stretch", height="stretch", horizontal_alignment="center"):
diff --git a/app/themes.py b/app/themes.py
new file mode 100644
index 0000000..e6b4472
--- /dev/null
+++ b/app/themes.py
@@ -0,0 +1,36 @@
+import streamlit as st
+from queries import crud
+
+def init_themes():
+
+    if 'themes' not in st.session_state:
+        st.session_state.themes = {
+            "dark": {
+                "theme.base": "dark",
+                "theme.backgroundColor": "black",
+                "theme.primaryColor": "#c98bdb",
+                "theme.secondaryBackgroundColor": "#5591f5",
+                "theme.textColor": "white",
+                "button_face_label": "Dark",
+                "button_face_icon": ":material/dark_mode:"
+            },
+            "light": {
+                "theme.base": "light",
+                "theme.backgroundColor": "white",
+                "theme.primaryColor": "#5591f5",
+                "theme.secondaryBackgroundColor": "#82E1D7",
+                "theme.textColor": "#0a1464",
+                "button_face_label": "Light",
+                "button_face_icon": ":material/light_mode:"
+            },
+        }
+
+    if 'current_theme' not in st.session_state:
+        st.session_state.current_theme = 'light'
+        change_theme('light')
+
+def change_theme(theme):
+    crud.set_theme(theme)
+    for key, val in st.session_state.themes[theme].items():
+        if key.startswith("theme"):
+            st._config.set_option(key, val)
diff --git a/app/user.py b/app/user.py
index 079aa32..45c3cc7 100644
--- a/app/user.py
+++ b/app/user.py
@@ -5,7 +5,4 @@ is_login_enabled = hasattr(st, 'user') and hasattr(st.user, 'is_logged_in')
 is_logged_in = is_login_enabled and st.user.is_logged_in
 
 def init_user():
-    if is_logged_in:
-        user_queries.set_user_in_session(st.user)
-    else:
-        st.session_state.user_id = 1  # default user
\ No newline at end of file
+    user_queries.set_user_in_session(st.user)
\ No newline at end of file
diff --git a/css/theme.css b/css/theme.css
index 0527b8a..c048a32 100644
--- a/css/theme.css
+++ b/css/theme.css
@@ -15,7 +15,6 @@
 }
 
 .stPageLink a {
-    background: whitesmoke;
     height: 40px;
     width: 45px;
     border: 1px solid silver;
@@ -34,7 +33,6 @@
     border: 1px solid gray;
     padding: 10px;
     border-radius: 5px;
-    background-color: whitesmoke;
 }
 
 .st-key-new_counter_color_selector div[role = "radiogroup"] {
diff --git a/migrations/versions/20260430181243_theme.py b/migrations/versions/20260430181243_theme.py
new file mode 100644
index 0000000..0fbbc2c
--- /dev/null
+++ b/migrations/versions/20260430181243_theme.py
@@ -0,0 +1,25 @@
+"""theme
+
+Revision ID: 8be315e8a5dc
+Revises: 720abfadcd44
+Create Date: 2026-04-30 18:12:43.026620
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = '8be315e8a5dc'
+down_revision: Union[str, Sequence[str], None] = '720abfadcd44'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+   op.add_column('users', sa.Column('theme', sa.String(), nullable=False, server_default='light'))
+
+def downgrade() -> None:
+    op.drop_column('users', 'theme')
diff --git a/tests/conftest.py b/tests/conftest.py
index a246392..46f442d 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -32,6 +32,7 @@ def user_config():
     st.session_state.user_name = "Test User"
     st.session_state.user_email = "test@test.local"
     st.session_state.user_external_id = "111-2222-3333"
+    st.session_state.current_theme = "light"
 
 @pytest.fixture
 def app() -> AppTest:
diff --git a/tests/ui/settings_ui_test.py b/tests/ui/settings_ui_test.py
index 5373dab..d09d29c 100644
--- a/tests/ui/settings_ui_test.py
+++ b/tests/ui/settings_ui_test.py
@@ -1,15 +1,33 @@
 
+import queries.crud as crud
+
+def test_change_theme(app):
+    app.run()
+    app.switch_page("pages/settings.py").run()
+
+    assert app.session_state.current_theme =="light", "Light theme should be default"
+
+    assert app.button[0].label == "Light"
+    assert app.button[0].disabled == True, "Light theme should be selected"
+
+    assert app.button[1].label == "Dark"
+    assert app.button[1].disabled == False, "Dark theme should be de-selected"
+
+    app.button[1].click().run()
+
+    assert "dark" == crud.get_theme()
+
 def test_change_color_palette(app):
     app.run()
     app.switch_page("pages/settings.py").run()
 
-    assert app.button[0].disabled == True
-    assert app.button[0].label == "Flames **(selected)**"
+    assert app.button[2].disabled == True, "First palette should be selected"
+    assert app.button[2].label == "Flames **(selected)**"
 
-    app.button[1].click().run()
+    app.button[3].click().run()
 
-    assert app.button[0].disabled == False
-    assert app.button[0].label == "Flames"
+    assert app.button[2].disabled == False, "First palette should be de-selected"
+    assert app.button[2].label == "Flames"
 
-    assert app.button[1].disabled == True
-    assert app.button[1].label == "Water **(selected)**"
\ No newline at end of file
+    assert app.button[3].disabled == True, "Second palette should be selected"
+    assert app.button[3].label == "Water **(selected)**"
\ No newline at end of file