Unable to run app after editing

[jennAllen]

During the QA bug bash I used the default Geyser template as my starting point. I removed the original plot item in the upper right and added a couple of other UI elements. After I stopped the editor and attempted to run the App, I got an error:

=> Shutting down running shiny app... 
> runApp('~/Desktop/bug_bash')
Error in card_header("Settings") : could not find function "card_header"

This is what my app looked like in the editor:

And here is the app.R code:

library(shiny)
library(plotly)
library(gridlayout)
library(bslib)
library(DT)

ui <- grid_page(
  layout = c(
    "header  header header",
    "sidebar area4  area5 ",
    "table   table  plotly",
    "table   table  plotly"
  ),
  row_sizes = c(
    "40px",
    "0.83fr",
    "1.17fr",
    "1fr"
  ),
  col_sizes = c(
    "250px",
    "1.13fr",
    "0.87fr"
  ),
  gap_size = "1rem",
  grid_card(
    area = "sidebar",
    card_header("Settings"),
    card_body(
      sliderInput(
        inputId = "bins",
        label = "Number of Bins",
        min = 12,
        max = 100,
        value = 30,
        width = "100%"
      ),
      numericInput(
        inputId = "numRows",
        label = "Number of table rows",
        value = 10,
        min = 1,
        step = 1,
        width = "100%"
      )
    )
  ),
  grid_card_text(
    area = "header",
    content = "GEYSER - TEST APP",
    alignment = "center",
    is_title = TRUE
  ),
  grid_card(
    area = "table",
    card_header(
      "Table",
      selectInput(
        inputId = "mySelectInput",
        label = "Select Input",
        choices = list("Option A" = "A", "Option B" = "B", "Option C" = "C")
      )
    ),
    card_body(DTOutput(outputId = "myTable", width = "100%"))
  ),
  grid_card(
    area = "plotly",
    card_header("Interactive Plot"),
    card_body(
      plotlyOutput(
        outputId = "distPlot",
        width = "100%",
        height = "100%"
      )
    )
  ),
  grid_card(
    area = "area4",
    card_body(
      radioButtons(
        inputId = "myRadioButtons",
        label = "Radio Buttons",
        choices = list(
          "choice a" = "a",
          "choice b" = "b",
          "Value3" = "value3",
          "Value4" = "value4",
          "Value5" = "value5",
          "Value6" = "value6"
        ),
        width = "100%"
      )
    )
  ),
  grid_card(
    area = "area5",
    card_body(textOutput(outputId = "textOutput"))
  )
)

server <- function(input, output) {

  output$distPlot <- renderPlotly({
    # generate bins based on input$bins from ui.R
    plot_ly(x = ~ faithful[, 2], type = "histogram")
  })

  output$bluePlot <- renderPlot({
    # generate bins based on input$bins from ui.R
    x <- faithful[, 2]
    bins <- seq(min(x), max(x), length.out = input$bins + 1)

    # draw the histogram with the specified number of bins
    hist(x, breaks = bins, col = "purple", border = "white")
  })

}

shinyApp(ui, server)