R shiny how to “box” a simple text on a shiny page

Question

I'm using documentation https://shiny.rstudio.com/tutorial/written-tutorial/lesson2/ and more precisely the following code to add a simple paragraph to my shiny page:

ui <- fluidPage(
  titlePanel("My Shiny App"),
  sidebarLayout(
    sidebarPanel(),
    mainPanel(
      p("p creates a paragraph of text."),
      p("A new p() command starts a new paragraph. Supply a style attribute to change the format of the entire paragraph.", style = "font-family: 'times'; font-si16pt"),
      strong("strong() makes bold text."),
      em("em() creates italicized (i.e, emphasized) text."),
      br(),
      code("code displays your text similar to computer code"),
      div("div creates segments of text with a similar style. This division of text is all blue because I passed the argument 'style = color:blue' to div", style = "color:blue"),
      br(),
      p("span does the same thing as div, but it works with",
        span("groups of words", style = "color:blue"),
        "that appear inside a paragraph.")
    )
  )
)

My goal is to take any of these paragraphs, let's say the last one, and display it like inside a box the same way we can see it here: http://www.sthda.com/english/articles/40-regression-analysis/168-multiple-linear-regression-in-r/
where it says "library(tidyverse)", this paragraph is inside a box with a different background color. Does anyone know how I can achieve that? I don't know much about HTML hence the hard time I'm facing. Thank you

Answer 1

It's not about HTML it's CSS what you should look for. (;

For example you could copy & paste the CSS styling rules from the webpage you linked into you shiny app (not the recommend way but quick & dirty) to change the appearance of the code tag like so:

library(shiny)

ui <- fluidPage(
    tags$head(
        tags$style(HTML("
            code {
                display:block;
                padding:9.5px;
                margin:0 0 10px;
                margin-top:10px;
                font-size:13px;
                line-height:20px;
                word-break:break-all;
                word-wrap:break-word;
                white-space:pre-wrap;
                background-color:#F5F5F5;
                border:1px solid rgba(0,0,0,0.15);
                border-radius:4px; 
                font-family:monospace;
            }"))),
    titlePanel("My Shiny App"),
    sidebarLayout(
        sidebarPanel(),
        mainPanel(
            p("p creates a paragraph of text."),
            p("A new p() command starts a new paragraph. Supply a style attribute to change the format of the entire paragraph.", style = "font-family: 'times'; font-si16pt"),
            strong("strong() makes bold text."),
            em("em() creates italicized (i.e, emphasized) text."),
            br(),
            code("code displays your text similar to computer code"),
            div("div creates segments of text with a similar style. This division of text is all blue because I passed the argument 'style = color:blue' to div", style = "color:blue"),
            br(),
            p("span does the same thing as div, but it works with",
              span("groups of words", style = "color:blue"),
              "that appear inside a paragraph.")
        )
    )
)

server <- function(input, output) {

}

shinyApp(ui = ui, server = server)