虽然放置正确width: 50%
要更改下拉组件的宽度,您已将其放置在内部组件而不是父 Div 中。
app.layout = html.Div(
children=[
html.H1(children="Welcome to Portfolio Construction Engine!"),
html.Div(
children="What would you like to do?",
style={"font-style": "italic", "font-weight": "bold"},
),
html.Div(
[
dcc.Dropdown(
id="demo-dropdown",
options=[
{"label": "Upload Scores", "value": "upload_scores"},
{"label": "Analyze Portfolios", "value": "analyze_portfoliio"},
{
"label": "Generate Data for IC Engine",
"value": "gen_data_ic_engine",
},
],
placeholder="Select a task...",
# style={"width": "50%"}, NOT HERE
),
html.Div(id="dd-output-container"),
],
style={"width": "50%"},
),
]
)