Checklist

• I have searched the existing issues for similar issues.
• I added a very descriptive title to this issue.
• I have provided sufficient information below to help reproduce this issue.

Summary

st.toast does not utilize any of the background colors from custom theme configuration.

Reproducible Code Example

import streamlit as st

st.dataframe({"A": [1, 2, 3], "B": [4, 5, 6]}, on_select="rerun")
st.sidebar.dataframe({"A": [1, 2, 3], "B": [4, 5, 6]}, on_select="rerun")

if st.button("Toast"):
    st.toast("This is a toast message", icon="✅")

st.selectbox("Choose an option", ["Option 1", "Option 2"])

Steps To Reproduce

[theme]
dataframeHeaderBackgroundColor = "#FF0000"
backgroundColor = "#ffff00"
secondaryBackgroundColor = "#00ff00"

[theme.sidebar]
dataframeHeaderBackgroundColor = "#0000ff"
backgroundColor = "#00ffff"
secondaryBackgroundColor = "#ff00ff"

Expected Behavior

No response

Current Behavior

No response

Is this a regression?

• Yes, this used to work in a previous version.

Debug info

• Streamlit version: 1.46.2.dev20250714
• Python version: 3.13
• Operating System: Mac
• Browser: Prisma

Additional Information

A general request for toast customization is #7073