(defun beacon--color-range ()
"Return a list of background colors for the beacon."
(let* ((default-bg (or (save-excursion
- (forward-line 1)
- (forward-char -1)
+ (unless (eobp)
+ (forward-line 1)
+ (unless (bobp) (forward-char -1)))
(background-color-at-point))
(face-background 'default)))
(bg (color-values (if (string-match "\\`unspecified-" default-bg)