Sometimes it is convenient to break CSS function calls up in multiple
lines. The current CSS indentation engine does not handle this well
when the parameters don't begin at the same line as the opening
paren. For instance:

div {
    background: linear-gradient(
                        to right, red, orange, yellow,
                        green, blue, indigo, violet
                    );
}

div {
    background: linear-gradient(
                        135deg,
                        red,
                        blue
                    );
}

I would instead expect the following indentation:

div {
    background: linear-gradient(
        to right, red, orange, yellow,
        green, blue, indigo, violet
    );
}

div {
    background: linear-gradient(
        135deg,
        red,
        blue
    );
}

The following patch accomplishes this:

diff --git a/lisp/textmodes/css-mode.el b/lisp/textmodes/css-mode.el
index f6a3ca6..ab911ce 100644
--- a/lisp/textmodes/css-mode.el
+++ b/lisp/textmodes/css-mode.el
@@ -331,8 +331,9 @@
     (`(:elem . basic) css-indent-offset)
     (`(:elem . arg) 0)
     (`(:list-intro . ,(or `";" `"")) t) ;"" stands for BOB (bug#15467).
-    (`(:before . "{") (if (smie-rule-hanging-p)
-                         (smie-rule-parent 0)))))
+    (`(:before . ,(or "{" "("))
+     (if (smie-rule-hanging-p)
+         (smie-rule-parent 0)))))

 ;;;###autoload
 (define-derived-mode css-mode fundamental-mode "CSS"


In GNU Emacs 25.0.50.11 (x86_64-unknown-linux-gnu, GTK+ Version 3.14.5)
 of 2015-02-08 on x240
Repository revision: dcec731abfc110f719f0890fd0769e099393af7d
Windowing system distributor `The X.Org Foundation', version 
11.0.11602901
System Description:	Debian GNU/Linux 8.0 (jessie)

Configured using:
 `configure --without-makeinfo'

Configured features:
XPM JPEG TIFF GIF PNG SOUND DBUS GSETTINGS NOTIFY LIBXML2 FREETYPE XFT
ZLIB

Important settings:
  value of $LANG: en_US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t

Recent messages:
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None found.

Features:
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ietf-drums mm-util help-fns mail-prsvr mail-utils time-date tooltip
eldoc electric uniquify ediff-hook vc-hooks lisp-float-type mwheel x-win
x-dnd tool-bar dnd fontset image regexp-opt fringe tabulated-list
newcomment elisp-mode lisp-mode prog-mode register page menu-bar
rfn-eshadow timer select scroll-bar mouse jit-lock font-lock syntax
facemenu font-core frame cham georgian utf-8-lang misc-lang vietnamese
tibetan thai tai-viet lao korean japanese hebrew greek romanian slovak
czech european ethiopic indian cyrillic chinese case-table epa-hook
jka-cmpr-hook help simple abbrev minibuffer cl-preloaded nadvice
loaddefs button faces cus-face macroexp files text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote make-network-process dbusbind
gfilenotify dynamic-setting system-font-setting font-render-setting
move-toolbar gtk x-toolkit x multi-tty emacs)

Memory information:
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 (symbols 48 17996 0)
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