Try to change company-box child-frame background color when circadian switch theme about company-box HOT 2 OPEN

(defun company-box--display (string)
  "Display the completions."
  (company-box--render-buffer string)
  (unless (company-box--get-frame) ; the already created child-frame exist, so will not apply following new child-frame parameters.
    (company-box--set-frame (company-box--make-frame)))
  (company-box--set-frame-position (company-box--get-frame))
  (unless (frame-visible-p (company-box--get-frame))
    (make-frame-visible (company-box--get-frame)))
  (company-box--update-scrollbar (company-box--get-frame) t))

;; delete old child-frame, then `company-box' create new child-frame.
    (delete-frame (company-box--get-frame))
    (unless (company-box--get-frame)
      (company-box--set-frame (company-box--make-frame)))
    (delete-frame (frame-parameter nil 'company-box-doc-frame))
    (unless (frame-live-p (frame-parameter nil 'company-box-doc-frame))
      (set-frame-parameter nil 'company-box-doc-frame nil))

(setq-default company-box-frame-parameters company-box-frame-parameters)
  (defun my:company-box-faces-setup (theme)
    "Reload company-box faces on `circadian' `THEME' toggling."
    ;; delete old child-frame, then `company-box' create new child-frame.
    (delete-frame (company-box--get-frame))
    (unless (company-box--get-frame)
      (company-box--set-frame (company-box--make-frame)))
    (delete-frame (frame-parameter nil 'company-box-doc-frame))
    (unless (frame-live-p (frame-parameter nil 'company-box-doc-frame))
      (set-frame-parameter nil 'company-box-doc-frame nil))
    
    (set-face-attribute 'company-box-candidate nil
                        :inherit nil
                        :family (face-attribute 'default :family)
                        :foreground (face-foreground 'default))
    (set-face-attribute 'company-box-selection nil
                        :inherit 'company-tooltip-selection)
    (set-face-attribute 'company-box-background nil
                        :background (cl-case (alist-get 'background-mode (frame-parameters))
                                      ('light "#EBF4FE")
                                      ('dark (color-lighten-name (face-background 'default) 4))))
    (add-to-list 'company-box-frame-parameters
                 `(background-color . ,(cl-case (alist-get 'background-mode (frame-parameters))
                                         ('light "#EBF4FE")
                                         ('dark (color-lighten-name (face-background 'default) 4)))))
    (add-to-list 'company-box-frame-parameters
                 `(foreground-color . ,(face-foreground 'default)))
    )
  (add-hook 'circadian-after-load-theme-hook #'my:company-box-faces-setup)