These screenshots show how Emacs looks when writing a DTD customization layer using the blue theme and an XSL stylsheet customization layer using the green theme. The screenshots show Emacs in dtd-mode and xsl-mode, respectively.

The files shown in the images are real customization layers of the DocBook XML Slides DTD and XSL styleshseets.

Again, the screenshot images are large (~500x900 pixels), but file sizes are not (<15k).