[gnome-nibbles/arnaudb/kill-preferences-dialog] Remove CSS warnings.

[Arnaud B. <arnaudb src gnome org>]

commit c811f143ae974030712325fdc2b54370d6ea2366
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Mon Jun 15 20:21:43 2020 +0200

    Remove CSS warnings.

 data/nibbles.css | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)
---
diff --git a/data/nibbles.css b/data/nibbles.css
index aadaa31..8bdcfb3 100644
--- a/data/nibbles.css
+++ b/data/nibbles.css
@@ -27,24 +27,25 @@ window {
 * * players screen
 \*/
 
-.number-box {
+button.toggle.text-button.number-box {
   font-size: 3em;
   font-weight: bold;
   font-family: Sans;
 
   padding: 1px 38px;
-  background-image: linear-gradient(to bottom, #3e4444);
+  background-color: #3e4444;
+  background-image: none;
 
   color:@theme-fg-color;
 }
-.number-box:disabled {
+button.toggle.text-button.number-box:disabled {
   color:@theme-fg-color;
 }
-.number-box:hover {
-  background-image: linear-gradient(to bottom, rgba(60, 69, 71, 0.8));
+button.toggle.text-button.number-box:hover {
+  background-color: rgba(60, 69, 71, 0.8);
 }
-.number-box:checked {
-  background-image: linear-gradient(to bottom, #215d9c);
+button.toggle.text-button.number-box:checked {
+  background-color: #215d9c;
 }
 
 /*\
@@ -52,7 +53,8 @@ window {
 \*/
 
 /* the speed buttons */
-.speed-box
+button.toggle.text-button.speed-box,
+modelbutton.flat.speed-box
 {
   font-size: 1.5em;
   font-weight: bold;
@@ -60,18 +62,22 @@ window {
 
   min-width:20em;
   padding: 1em 1.5em 1em 1.5em;
-  background-image: linear-gradient(to bottom, #3e4444);
+  background-color: #3e4444;
+  background-image: none;
 
   color:@theme-fg-color;
 }
-.speed-box:disabled {
+button.toggle.text-button.speed-box:disabled,
+modelbutton.flat.speed-box:disabled {
   color:@theme-fg-color;
 }
-.speed-box:hover {
-  background-image: linear-gradient(to bottom, rgba(60, 69, 71, 0.8));
+button.toggle.text-button.speed-box:hover,
+modelbutton.flat.speed-box:hover {
+  background-color: rgba(60, 69, 71, 0.8);
 }
-.speed-box:checked {
-  background-image: linear-gradient(to bottom, #215d9c);
+button.toggle.text-button.speed-box:checked,
+modelbutton.flat.speed-box:checked {
+  background-color: #215d9c;
 }
 
 /* the empty space */