Streamlit doesn't seem to support

Context: I’m trying to apply a backgound color change on a streamlit app on the headers and indices of a multi-index dataframe:

arrays = [
    ["bar", "bar", "baz", "baz", "foo", "foo", "qux", "qux"],
    ["one", "two", "one", "two", "one", "two", "one", "two"],
tuples = list(zip(*arrays))

index = pd.MultiIndex.from_tuples(tuples, names=[None, "Brand"])

df = pd.DataFrame(np.random.randn(3, 8), index=["A", "B", "C"], columns=index)

When using applymap_index, this should change the background color as follows:

st.dataframe( x: "background-color:yellow;"))

This should work because using applymap alone inserts the background color on the cells of the dataframe, but applymap_index which should change the index background colors doesn’t.

How can I then change the background color of the indices? (columns/headers and indices?)