Plotly_chart theme="streamlit" documentation

Is there a documentation for exact parameters used in Streamlit theme for Plotly charts (e.g., title/axis title font, font size, position, chart color scheme, margins, etc.)?

I saw the documentation page with examples (https://plotly.streamlit.app/), but I couldn’t find the code for how the Streamlit theme itself is configured.

One specific property I can’t figure out is the space between plot border and axes. How is y=0 treated in the screenshot below? It’s not taking the blue color from the gridcolor argument, nor the thicker black from the showline argument.

See screenshot and code below - the exact same code was used to produce both charts except for theme=“streamlit” and theme=None (and titles accordingly).

Thank you for your help!

Justinas

    fig = go.Figure()
    fig.add_trace(
        go.Scatter(
            x=[0, 1, 2, 3, 4],
            y=[0, 2, 4, 2, 0],
            line=dict(color="green", width=4),
        )
    )
    fig.update_layout(
        title="streamlit themed chart",
        yaxis_title="y-value",
        xaxis_title="x-value",
        paper_bgcolor="rgba(213,213, 213,50)",
        plot_bgcolor="rgba(255,220,220,50)",
        yaxis_range=[0, 6],
        xaxis_range=[0, 6],
    )

    fig.update_xaxes(showline=True, linewidth=2, linecolor="black")

    fig.update_yaxes(
        showline=True,
        linewidth=2,
        linecolor="black",
        gridwidth=1,
        gridcolor="blue",
    )
    st.plotly_chart(fig, theme="streamlit", use_container_width=True)