It's more logical to use min-height:0 instead of overflow: auto. What you face is due to the default min-height/min-width setting applied by flexbox: w3.org/TR/css-flexbox-1/#min-size-...
overflow:auto will also disable the automatic minimum (w3.org/TR/css-flexbox-1/#change-20...) size but it's more suitable when you want to have a scrollbar.
It's more logical to use
min-height:0instead ofoverflow: auto. What you face is due to the default min-height/min-width setting applied by flexbox: w3.org/TR/css-flexbox-1/#min-size-...overflow:auto will also disable the automatic minimum (w3.org/TR/css-flexbox-1/#change-20...) size but it's more suitable when you want to have a scrollbar.
Thanks!