title: How to reduce the border width of sideBarPanel in Shiny?
body: <p>I can't for the life of me find an argument or SO question regarding this, so I'm asking:</p>
  
  <p><strong>How do you modify the size (width or height) of the gap border around a <code>sideBarPanel</code>?</strong></p>
  
  <p>My best solution has been to play with border values via <code>div</code> for individual elements, but I'm wondering how to change the border around the whole thing? </p>
  
  <p>The goal is to reduce the border gap so that I have "more room" for my elements when I zoom in (instead of them getting scrunched). </p>
  
  <p>Here's sample code showing the "problem":</p>
  
  <pre><code>library(shiny)
  
  ui &lt;- fluidPage(
  
    titlePanel(
      h1("NMS Comparing tool", style = "font-size: 15px")
    ),
  
    sidebarPanel(width = 3, 
                 div(style = "font-size: 8px;", 
                     sliderInput(inputId = "groups", 
                                 label = "No. of Groups",
                                 value = 4, min = 2, max = 12)
                 ),  
  
                 fluidRow(
                   column(6,offset=0,
                          div(style = "height: 105px; padding: 0px 0px",  
                              plotOutput(outputId = "scree")
                          )
                   ),
  
                   column(6,offset=0,
                          div(style = "font-size: 8px;padding: 0px 48px 15px; height: 105px",  #padding is top, right, bottom, left??
                              checkboxGroupInput(inputId = "labels",
                                                 label = "Labels",
                                                 choices = c("SPEC","Plot-End","Plot-Start"),
                                                 selected = c("SPEC","Plot-End","Plot-Start")
                              )    
                          )
                   )
                 ),
  
                 fluidRow(
                   column(6,offset=0,
                          div(style = "font-size: 8px; padding: 0px 0px",      
                              radioButtons(inputId = "data",
                                           label = "Data",
                                           choices = c("PSP Only","PSP + MAP"),
                                           selected = "PSP + MAP")
                          )    
                   ),
  
                   column(6,offset=0,
                          div(style = "font-size: 8px;padding: 0px 10px;",  
                              radioButtons(inputId = "freq",
                                           label = "Frequency",
                                           choices = c(0.025,0.05),
                                           selected = 0.05)
                          )
                   )
                 ),
  
                 fluidRow(
                   column(6,offset=0,
                          div(style = "font-size: 8px; padding: 0px 0px; ",                 
                              radioButtons(inputId = "arrows",
                                           label = "Vector Choice",
                                           choices = c("Cumulative Change","All Samples","Hurricane"),
                                           selected = "Cumulative Change")
                          )
                   ),
  
                   column(6,offset=0,
                          div(style = "font-size: 8px;padding: 0px 10px",      
                              selectInput(inputId = "size",
                                          label = "Tree Size",
                                          choices = c("All","Canopy","Subcanopy","Small"),
                                          selected = "All"),
                              tags$style(type = "text/css",
                                         #".select-dropdown-content {max-height: 4px; }")
                                         "#size {height: 4px; }")
                          )
                   )
                 ),
  
                 fluidRow(
                   tags$style(type="text/css", "#info {font-size: 10px;}"),
                   verbatimTextOutput("info")
                 ),
                 fluidRow(
                   tags$style(type="text/css", "#SPECinfo {font-size: 10px;}"),
                   verbatimTextOutput("SPECinfo")
                 )
    ),
  
    mainPanel(width = 9,
              plotOutput(outputId = "nms", click = "plot_click",dblclick = "plot_dblclick")
  
    )
  )
  
  server &lt;- function(input, output) {
  
    output$scree &lt;- renderPlot({
  
      par(mar = c(1.5,1.4,0.1,0.1), mgp = c(0.5,0.01,0), tcl = -0.1)
      plot(runif(99),runif(99),cex.axis=0.5,cex.lab=0.5,cex=0.75)
  
    },height = 95, width = 95) 
  
    output$nms &lt;- renderPlot({
  
      plot(runif(99),runif(99))
  
    })
  
  }
  
  shinyApp(ui = ui, server = server)
  </code></pre>