django-plotly-dash div大小太小，无法更改

<div class="custom-div"></div>

.custom-div {
  width: 500px;
  height: 300px;
}

import dash
import dash_bootstrap_components as dbc

app = dash.Dash(__name__, external_stylesheets=[dbc.themes.BOOTSTRAP])

app.layout = dbc.Container(
    dbc.Row(
        [
            dbc.Col(html.Div(id='div-id', className='custom-div'), width=6),
        ]
    )
)

if __name__ == '__main__':
    app.run_server(debug=True)

import dash
import dash_core_components as dcc
import plotly.graph_objs as go

app = dash.Dash(__name__)

app.layout = html.Div(
    dcc.Graph(
        id='graph-id',
        figure={
            'data': [
                go.Scatter(
                    x=[1, 2, 3],
                    y=[4, 1, 2],
                    mode='lines',
                    name='Line'
                )
            ],
            'layout': go.Layout(
                width=500,
                height=300
            )
        }
    )
)

if __name__ == '__main__':
    app.run_server(debug=True)