How can I replace in my .emacs all these `require` with `package.el` and `MELPA`?

Question

My .emacs still uses old-style (pre MELPA, pre package.el) initializations.

Current (this works)

I'll use web-mode as a concrete example.

If I manually download web-mode.el and put it in ~/elisp, then start Emacs (25) with the .emacs file

(package-initialize)  ; Irrelevant here. Added by Emacs.
(setq load-path
      (cons "~/elisp" load-path))

(require 'web-mode)

(set-face-attribute 'web-mode-css-at-rule-face nil :foreground "magenta red")

all is well.

I'd like to change this .emacs to be able to use any machine+account without having to install manually an ~/elisp on each machine/account.

MELPA + package.el attempt (this doesn't work)

My attempt is:

(require 'package)

(add-to-list 'package-archives
             '("MELPA Stable" . "https://stable.melpa.org/packages/") t)

(package-initialize)

(custom-set-variables
 '(package-selected-packages
   (quote
    (web-mode))))

(set-face-attribute 'web-mode-css-at-rule-face nil :foreground "magenta red")

but this fails with

error: Invalid face, web-mode-css-at-rule-face

What am I doing wrong?

Update

When I run package-list-packages I see

and so it appears that web-mode is installed.

I now have the impression from phil's comment that using package.el + MELPA may not actually spare me from having to download and install elisp packages manually. Please confirm one way or the other.

Post answer

It turns out that this change cannot be completely made. Too many packages are not on MELPA.

Answer 1

Untested, but I strongly suspect that what you need to do is:

(eval-after-load "web-mode"
  '(set-face-attribute 'web-mode-css-at-rule-face nil :foreground "magenta red"))

The web-mode package is evidentially installed, but it is not yet loaded, and so you were trying to use a face that is yet to be defined.