In the link you posted, there is a CSS section, which explains everything. But for a start this should be fine :)
library(shinydashboard)
ui <- dashboardPage(
dashboardHeader(title = "Custom font"),
dashboardSidebar(
# Custom CSS to hide the default logout panel
tags$head(tags$style(HTML('.logo {
background-color: #2666cc !important;
}
.navbar {
background-color: #2666cc !important;
}
'))),
# The dynamically-generated user panel
uiOutput("userpanel")
),
dashboardBody()
)
server <- function(input, output, session) {
output$userpanel <- renderUI({
# session$user is non-NULL only in authenticated sessions
if (!is.null(session$user)) {
sidebarUserPanel(
span("Logged in as ", session$user),
subtitle = a(icon("sign-out"), "Logout", href="__logout__"))
}
})
}
shinyApp(ui, server)