(add-to-list 'mu4e-header-info-custom
   '(:real-to .
       (:name "Real :to Address"
        :shortname "realto"
        :help ":to address without any aliases"
        :function (lambda (msg)
                     (cdr (nth 0 (mu4e-message-field msg :to)))))))

(setq mu4e-headers-fields
  '((:human-date .  12)
    (:flags      .   6)
    (:from       .  22)
    (:subject    . 80)
    (:real-to    . nil)))

(setq header-highlights
  '((".*public@mydomain.*" . email-public-face)
    (".*teacher@mydomain.*" . email-teacher-face)
    (".*iain@mydomain.*" . email-iain-face)
    (".*photos@mydomain.*" . email-photos-face)
    (".*iain@workdomain.com.*" . email-wiserobot-face)
    (".*@hotmail.com.*" . email-hotmail-face)
    (".*\(myname@me.com\|myname@icloud.com\).*" . email-me-face)))

(add-hook 'mu4e-headers-mode-hook
      (lambda ()
        (setq font-lock-defaults '(header-highlights))))

(defface email-public
  '((t :foreground "#bf9f00"))
  "Face for mail headers to public@mydomain"
  :group `basic-faces)
(defface email-teacher
  '((t :foreground "#9f009f"))
  "Face for mail headers to Teacher@mydomain"
  :group 'basic-faces)
(defface email-iain
  '((t :foreground "#009f00"))
  "Face for mail headers to iain@mydomain"
  :group 'basic-faces)
(defface email-photos
  '((t :foreground "#ef1010"))
  "Face for mail headers to photos@mydomain"
  :group 'basic-faces)
(defface email-wiserobot
  '((t :foreground "#0000e8"))
  "Face for mail headers to iain@workdomain"
  :group 'basic-faces)
(defface email-hotmail
  '((t :foreground "#7840f8"))
  "Face for mail headers to myname@hotmail.com"
  :group 'basic-faces)
(defface email-me
  '((t :foreground "#00c080"))
  "Face for mail headers to myname@me.com"
  :group 'basic-faces)


(setq email-public-face `email-public
  email-teacher-face 'email-teacher
  email-iain-face 'email-iain
  email-photos-face 'email-photos
  email-wiserobot-face 'email-wiserobot
  email-hotmail-face 'email-hotmail
  email-me-face 'email-me)