Refactor CSS rules for the shift-key.

ui/keyboard/resources/main.css

Index: ui/keyboard/resources/main.css
diff --git a/ui/keyboard/resources/main.css b/ui/keyboard/resources/main.css
index 2c5b621eb31fdd3f57947e841a288ad3e8f66769..99c2c2708057c4e80163df68d05d93cc3da135b4 100644
--- a/ui/keyboard/resources/main.css
+++ b/ui/keyboard/resources/main.css
@@ -18,18 +18,18 @@ kb-keyboard.alt-active kb-modifier-key[char=Alt] {
   color: lightblue;
 }
 
-kb-keyboard[keyset="upper"] kb-shift-key.dark /shadow-deep/ .key {
+kb-keyboard[keyset="upper"] kb-shift-key.dark /deep/ .key {
   background-image: url('images/shift-filled.svg');
 }
 
-kb-keyboard[keyset="lower"] kb-shift-key /shadow-deep/ .key {
+kb-keyboard[keyset="lower"] kb-shift-key /deep/ .key{
   background-image: url('images/shift.svg');
 }
 
 /**
 * Controls whether the shift key should be highlighted or not.
 */
-kb-keyboard.caps-locked kb-shift-key.dark /shadow-deep/
+kb-keyboard.caps-locked kb-shift-key.dark /deep/
     .shift-light {
   -webkit-box-shadow: 0 1px 1px rgba(213, 213, 213, 0.5),
     0 -1px 1px rgba(213, 213, 213, 0.5);
@@ -37,7 +37,7 @@ kb-keyboard.caps-locked kb-shift-key.dark /shadow-deep/
   border: none;
   height: 0.2em;
 }
-kb-keyboard.caps-locked kb-shift-key.dark /shadow-deep/
+kb-keyboard.caps-locked kb-shift-key.dark /deep/
     .shift-light-wrapper {
   bottom: 2px;
 }
@@ -72,15 +72,15 @@ kb-row:nth-child(n+3) kb-key:not(.dark):not(.active){
   border-top-color: #717171;
 }
 
-kb-row:nth-child(2) kb-key:not([invert]) /shadow-deep/ .hint {
+kb-row:nth-child(2) kb-key:not([invert]) /deep/ .hint {
   color: #2C2C2C;
 }
 
-kb-row:nth-child(3) kb-key:not([invert]) /shadow-deep/ .hint {
+kb-row:nth-child(3) kb-key:not([invert]) /deep/ .hint {
   color: #272727;
 }
 
-kb-row:nth-child(n+3) kb-key:not([invert]) /shadow-deep/ .hint {
+kb-row:nth-child(n+3) kb-key:not([invert]) /deep/ .hint {
   color: #232323;
 }