[BUG] Sidebar Button Position Not Relative

[mykolaskrynnyk]

Describe the bug

When enabling a sidebar, the button to open/close it is not properly positioned relative to the screen size. The position shifts up and down depending on screen resolution. For some resolutions, it is not visible altogether.

To Reproduce

import st_undp
import streamlit as st

st_undp.apply_style()

with st.sidebar:
    with st.form("qux"):
        for i in range(3):
            st.text_input(f"foo {i}")
        st.form_submit_button("bar", type="primary")

st.json(st.session_state)

Change display resolution to see the position shifts.

Expected behavior

The position should be relative to the height (of the viewport) so that the button's position is stable.

Screenshots

Desktop (please complete the following information):

All devices.

Smartphone (please complete the following information):

All devices.

Additional context

None.