You can use some custom CSS. If you're using the blue skin (which is the default) you can do something like this:
library(shiny)
library(shinydashboard)
ui <- dashboardPage(
dashboardHeader(),
dashboardSidebar(
sidebarMenu(
menuItem("A"),
menuItem("B")
)
),
dashboardBody(
tags$head(tags$style(HTML('
.skin-blue .main-sidebar {
background-color: #666666;
}
.skin-blue .sidebar-menu>li.active>a, .skin-blue .sidebar-menu>li:hover>a {
background-color: #444444;
}
')))
)
)
server <- function(input, output) {}
shinyApp(ui, server)
-Winston