bottom align a button in R shiny

Question

I cannot figure out a way to bottom align downloadButton with a selectizeInput, i.e.,

Answer 1

Found an ad-hoc fix with margin-top: 25px in the style tag...

library(shiny)

runApp(list(
  ui = shinyUI(fluidPage(
     h4("Download Options:"),
     fluidRow(
       column(6, selectizeInput("plot_dl", "File Type", width="100%",
                                choices = list("PDF"="pdf","PNG"="png"))),
       column(3, downloadButton('plot1_dl', 'Left Plot')),
       column(3, downloadButton('plot2_dl', 'Right Plot'))
     ),
     tags$style(type='text/css', "#plot1_dl { width:100%; margin-top: 25px;}"),
     tags$style(type='text/css', "#plot2_dl { width:100%; margin-top: 25px;}")
  )),
  server = function(input, output) {
  }
))