DatePicker.shinyInput flex grow

[Aisling-Kinsella]

Preface: new to shiny and shiny.fluent

I'm housing two shiny.fluent date pickers horizontally in a div within gridPanel. I'm trying to get the date picker inputs to grow and shrink to fill the div but can't select the date pickers individually to do this. The div grows and shrinks but the date pickers never change size.

` gridPanel(
              columns = "1fr 1fr",
              gap = "5px",
              
              div(class = "filter1",
                  style = "display: flex; width: 100%; align-items: stretch;",
                  Stack(
                    tokens = list(childrenGap = 10),
                    horizontal = TRUE,
                    style = "flex-grow: 1",
                    DatePicker.shinyInput("fromDate", value = as.Date("2019/01/01"), label = "From date"),
                    DatePicker.shinyInput("toDate", value = as.Date("2020/12/31"), label = "To date")
                  )`

How can I grab the DatePickers to style/ apply flex to individually.