Making a custom RStudio theme

Background colour

.ace_editor, .ace_editor_theme .profvis-flamegraph, .ace_editor_theme {
  background-color: #F7DCF0
}

This changes the background colour of RStudio’s panes, except for the terminal tab. It also doesn’t change the colour of the ‘gutter’, which is the part of the source pane where the line numbers appear.

Gutter colour

.ace_gutter {
  background: #F7DCF0
}

This will change the background colour of the ‘gutter’. I made it the same colour as the main part of the source pane but you can do whatever you like.

Terminal colour

.terminal {
  background-color: #F7DCF0;
  color: #000000;
}

In the default rstheme files there’s a bunch of other options in the terminal argument. Don’t know what they do, and I don’t really use terminal much either, I just wanted it all to be consistently coloured. background-color changes the background and color changes the cursor colour.

Cursor colour

.ace_cursor {
  color: #000000
}

This changes the colour of the cursor (the little bar indicating where you’re typing).

Selection colour

.ace_marker-layer .ace_selection {
  background: #82C28273
}

This is one of my favourites. When you select code it’ll have this colour as the background. In the example it would highlight code in this colour!

Bracket highlights

.ace_bracket {
  margin: 0 !important;
  border: 0 !important;
  background-color: rgba(0, 184, 25, 0.5);
}

This is my other favourite! When your code has brackets, putting the cursor one of a pair of brackets will highlight them both so you can see where the bracketed code starts and end. Super useful when you’re working with bracketception. Some of the default themes weren’t obvious enough for me so I made it pretty clear with this green. Note in this instance I used rgba rather than a colour hex code - the last input (0.5 in this case) defines the transparency. You can define transparency with hex codes too but this works fine.

Code chunks

.ace_marker-layer .ace_foreign_line {
  position: absolute;
  z-index: -1;
  background-color: #f6d1ed;
}

This one sets the colour of code chunks.

Default text

.ace_editor, .ace_editor_theme .profvis-flamegraph, .ace_editor_theme {
  color: #00006B
}

This is the colour the majority of the text in your editor will be, basically any text that isn’t one of the special types defined later.

Gutter text

.ace_gutter {
  color: #333
}

Remember the gutter? Well this is how you define what colour the line numbers will be.

Keywords

.ace_keyword {
  color: #9D00FF !important;
}

Special words like if and function will be this colour

Metadata

.ace_meta,
.ace_support.ace_constant.ace_property-value {
  color: #6585ae
}

Text in document headers will be this colour, like titles, YAML and the like.

TRUE/FALSE and italics

.ace_constant.ace_language {
  color: #D29380
}

This sets the colour of the words TRUE and FALSE, plus any italicised text in markdown docs. You can specify a more general argument than this by just using .ace_constant on its own, but I like to be able to easily tell the difference between bolded and italicised text when I’m writing RMarkdown documents.

Numeric constants and bold text

.ace_constant.ace_numeric {
  color: #FF8080
}

This sets the colour of numeric constants, for example the 8 in mutate(x = 8) would be this colour. It’s also the color that bolded text in markdown documents will be.

Strings

.ace_string {
  color: #009E18
}

This sets the colour of strings.

Comments

.ace_comment {
  color: #5E5E5E
}

This sets the colour of comments (you better be writing comments!).

Rainbow indent lines

.rstudio_rainbow_indent_guides .ace_line .ace_indent-guide:nth-child(2n+1){
    background: linear-gradient(to left, #f38989 1px, transparent 1px, transparent);
}
.rstudio_rainbow_indent_guides .ace_line .ace_indent-guide:nth-child(2n+2){
    background: linear-gradient(to left, #78c1a3 1px, transparent 1px, transparent);
}

If you don’t know what indents are, you can find them by going through the menus Tools -> Global Options -> Code -> Display -> Indentation guidelines. You can have a bit of fun changing these. The two things you need to pay attention to are the colours (obviously) and the nth-child(2n+1) statements. I’m making an assumption here, but I think the number before n indicates how many colours there are in your set of rainbow indent colours, and the number following the + indicate the ordering of the colours. So in the above example, #f38989 comes first and #78c1a3 comes second and repeats for however many indents you have.

Rainbow indent fills

.rstudio_rainbow_indent_fills .ace_line .ace_indent-guide:nth-child(2n+1){
    background: linear-gradient(to left, #f3898977 1px, #f3898977 1px, #f3898977);
}
.rstudio_rainbow_indent_fills .ace_line .ace_indent-guide:nth-child(2n+2){
    background: linear-gradient(to left, #78c1a377 1px, #78c1a377 1px, #78c1a377);
}

These are similar to the indent lines, except it fills the indents in blocks (vertically). The main difference here is the addition of two numbers at the end of the hex code, controlling the transparency. I’d suggest keeping the transparency, it looks weird with block colours!

Grey line indents

This the final thing I’ll mention, and I think the most interesting!

.ace_indent-guide {
  background: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAANSURBVBhXY9jYWl4GAAW8AiRaxbuHAAAAAElFTkSuQmCC") right repeat-y
}

It turns out that the grey line indents are actually tiny base64 images, so if you want to modify the colour to make them more visible you’ll need to create a new 1-pixel image. When I was creating my theme, the default colour of the theme I’d Frankensteined was too light to clearly see, so I ended up making a darker pixel for better contrast. I just made a 1-pixel image in paint and uploaded it to https://www.base64-image.de/ to get the base64 code used here.