latex-hl-line.el

(defface latex-hl-line
  '((t (:background "DeepSkyBlue4")))
  "Face for the lines start with \\documentclass[foo]{bar},
\\begin{document} or \\end{document}."
  :group (if (featurep 'font-latex)
             'font-latex-highlighting-faces
           'font-lock-faces))

(font-lock-add-keywords
 'latex-mode
 `((,(concat "^\\s-*\\\\\\("
             "documentclass\\(\\[[^]% \t\n]*\\]\\)?{[-[:alnum:]_]+"
             "\\|"
             "\\(begin\\|end\\){document"
             "\\)}.*\n?")
    (0 'latex-hl-line append))))