title: Changing the width of the borders in a Plotly treemap
body: <p>Is it possible to change the width of the borders in a Plotly treemap? I am referring to the white borders separating each individual box in the treemap below.</p>
  <pre><code>import plotly.express as px
  df = px.data.tips()
  fig = px.treemap(df, path=[px.Constant(&quot;all&quot;), 'day', 'time', 'sex'], values='total_bill')
  fig.update_traces(root_color=&quot;lightgrey&quot;)
  fig.update_layout(margin = dict(t=50, l=25, r=25, b=25))
  fig.show()
  </code></pre>
  <p><a href="https://i.stack.imgur.com/Gr7ni.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Gr7ni.png" alt="enter image description here" /></a></p>
  <p>Edit:
  A workaround is to change <code>stroke-width</code> in the resulting SVG file. However, it would be nice if this can be done automatically.</p>