Hi @autosun,
I am as newbie as you concerning Dash, but I guess that the answer you are looking for is CSS. You may try to add the keyword “verticalAlign” (or “vertical-align” depending on how you define your dictionary) in your style dictionary.
html.Div([
dcc.Graph(
id='figure1',
figure=charts()
),
], style={'width': '49%', 'display': 'inline-block', 'vertical-align': 'middle'}),
Didn’t actually try it, but it should work. There are more options available that you can find here.