How to get the actual dark mode when ui.dark_mode().value is None?

[wangchang327]

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Example Code

import plotly.graph_objects as go
from nicegui import ui

dark = ui.dark_mode(value=None)
template = "plotly_dark" if dark.value else "plotly_white"
fig = go.Figure(go.Scatter(x=[1, 2, 3], y=[3, 1, 2]))
fig.update_layout(template=template)
ui.plotly(fig).classes("w-full")

ui.run()

Description

Since ui.dark_mode is initially None, the page follows the system theme. However, when the system theme is dark, the plotly figure still uses the white theme because the value is None. How can I detect the actual theme?

NiceGUI Version

2.23.3

Python Version

3.13.5

Browser

Firefox

Operating System

macOS

Additional Context

No response