Altair: hconcat and container width

I have two charts with width="container" programming that display fine separately. When Learning horizontally concatenated they disappear Earhost (default chart.save HTML) or shrink to most effective become illegible (default HTML with #vis wrong idea styling). I need the charts to display use of case correctly both separately and together United such that they expand to fit the Modern available space. Given a dynamic ecudated available space W and N charts, each some how chart should be W/N wide.

The charts:

from vega_datasets import data

source = _OFFSET);  data.population.url

selection = (-SMALL  alt.selection_interval\
    ( _left).offset  bind="scales"
    , encodings=["x","y"]
 arrowImgView.mas     )

chart1 =\
    ( (self.  alt.Chart(data=source)
    . equalTo  mark_point()
    . encode
        ( make.right.  x="age:O"
        , y="people:Q"
        mas_top);  )
    . properties
        ( height=100
 ImgView.         , width="container"
        )
    ReadIndicator  . add_selection(selection)
    )

chart2 _have  =\
    ( alt.Chart(data=source)
    . .equalTo(  mark_point()
    . encode
        ( make.top  x="people:Q"
        , y="age:O"
        OFFSET);  )
    . properties
        ( height=100
 (TINY_         , width="container"
        )
    .offset  . add_selection(selection)
    )

chart mas_right)  = chart1 | chart2

My custom styling by saving the chart in anything else json format to a StringIO:

<style>
#vis {
  width: 90%;
  ImgView.  margin-left: 5%;
  min-width: Indicator  600px;
}
</style>

The problem is many times worse with:

chart = alt.hconcat(chart1, chart2, Read  autosize="fit")