Use .box-shadow() mixin so we can enable/disable them

dist/css/bootstrap-theme.css

@@ -182,7 +182,6 @@
   background-color: #c12e2a;
   background-image: none;
 }
-.thumbnail,
 .img-thumbnail {
   -webkit-box-shadow: 0 1px 2px rgba(0, 0, 0, .075);
           box-shadow: 0 1px 2px rgba(0, 0, 0, .075);

dist/css/bootstrap.css

@@ -3376,8 +3376,8 @@ select[multiple].input-group-sm > .input-group-btn > .btn {
   margin-left: -.75rem;
   border-top: 1px solid transparent;
   border-bottom: 1px solid transparent;
-  -webkit-box-shadow: inset 0 1px 0 rgba(255, 255, 255, .1), 0 1px 0 rgba(255, 255, 255, .1);
-          box-shadow: inset 0 1px 0 rgba(255, 255, 255, .1), 0 1px 0 rgba(255, 255, 255, .1);
+  -webkit-box-shadow: inset 0 1px 0 rgba(255,255,255,.1), 0 1px 0 rgba(255,255,255,.1);
+          box-shadow: inset 0 1px 0 rgba(255,255,255,.1), 0 1px 0 rgba(255,255,255,.1);
 }
 @media (min-width: 48em) {
   .navbar-form .form-group {
@@ -4635,7 +4635,6 @@ button.close {
   background-color: #fff;
   -webkit-background-clip: padding-box;
           background-clip: padding-box;
-  border: 1px solid #ccc;
   border: 1px solid rgba(0, 0, 0, .2);
   border-radius: .3rem;
   -webkit-box-shadow: 0 5px 10px rgba(0, 0, 0, .2);

docs/dist/css/bootstrap-theme.css

@@ -182,7 +182,6 @@
   background-color: #c12e2a;
   background-image: none;
 }
-.thumbnail,
 .img-thumbnail {
   -webkit-box-shadow: 0 1px 2px rgba(0, 0, 0, .075);
           box-shadow: 0 1px 2px rgba(0, 0, 0, .075);

docs/dist/css/bootstrap.css

@@ -3376,8 +3376,8 @@ select[multiple].input-group-sm > .input-group-btn > .btn {
   margin-left: -.75rem;
   border-top: 1px solid transparent;
   border-bottom: 1px solid transparent;
-  -webkit-box-shadow: inset 0 1px 0 rgba(255, 255, 255, .1), 0 1px 0 rgba(255, 255, 255, .1);
-          box-shadow: inset 0 1px 0 rgba(255, 255, 255, .1), 0 1px 0 rgba(255, 255, 255, .1);
+  -webkit-box-shadow: inset 0 1px 0 rgba(255,255,255,.1), 0 1px 0 rgba(255,255,255,.1);
+          box-shadow: inset 0 1px 0 rgba(255,255,255,.1), 0 1px 0 rgba(255,255,255,.1);
 }
 @media (min-width: 48em) {
   .navbar-form .form-group {
@@ -4635,7 +4635,6 @@ button.close {
   background-color: #fff;
   -webkit-background-clip: padding-box;
           background-clip: padding-box;
-  border: 1px solid #ccc;
   border: 1px solid rgba(0, 0, 0, .2);
   border-radius: .3rem;
   -webkit-box-shadow: 0 5px 10px rgba(0, 0, 0, .2);

less/button-groups.less

@@ -117,11 +117,11 @@
 // The clickable button for toggling the menu
 // Remove the gradient and set the same inset shadow as the :active state
 .btn-group.open .dropdown-toggle {
-  box-shadow: inset 0 3px 5px rgba(0,0,0,.125);
+  .box-shadow(inset 0 3px 5px rgba(0,0,0,.125));
 
   // Show no shadow for `.btn-link` since it has no other button styles.
   &.btn-link {
-    box-shadow: none;
+    .box-shadow(none);
   }
 }
 

less/buttons.less

@@ -39,7 +39,7 @@
   &.active {
     outline: 0;
     background-image: none;
-    box-shadow: inset 0 3px 5px rgba(0,0,0,.125);
+    .box-shadow(inset 0 3px 5px rgba(0,0,0,.125));
   }
 
   &.disabled,
@@ -48,7 +48,7 @@
     cursor: not-allowed;
     pointer-events: none; // Future-proof disabling of clicks
     opacity: .65;
-    box-shadow: none;
+    .box-shadow(none);
   }
 }
 
@@ -90,7 +90,7 @@
   &[disabled],
   fieldset[disabled] & {
     background-color: transparent;
-    box-shadow: none;
+    .box-shadow(none);
   }
   &,
   &:hover,

less/code.less

@@ -17,7 +17,7 @@ code {
   font-size: 90%;
   color: @code-color;
   background-color: @code-bg;
-  border-radius: @border-radius-base;
+  .border-radius(@border-radius-base);
 }
 
 // User input typically entered via keyboard
@@ -26,13 +26,13 @@ kbd {
   font-size: 90%;
   color: @kbd-color;
   background-color: @kbd-bg;
-  border-radius: @border-radius-small;
-  box-shadow: inset 0 -.1rem 0 rgba(0,0,0,.25);
+  .border-radius(@border-radius-small);
+  .box-shadow(inset 0 -.1rem 0 rgba(0,0,0,.25));
 
   kbd {
     padding: 0;
     font-size: 100%;
-    box-shadow: none;
+    .box-shadow(none);
   }
 }
 

less/dropdowns.less

@@ -44,7 +44,7 @@
   background-color: @dropdown-bg;
   border: 1px solid @dropdown-border;
   .border-radius(@border-radius-base);
-  box-shadow: 0 6px 12px rgba(0,0,0,.175);
+  .box-shadow(0 6px 12px rgba(0,0,0,.175));
   background-clip: padding-box;
 
   // Dividers (basically an hr) within the dropdown

less/forms.less

@@ -123,7 +123,7 @@ output {
   background-image: none; // Reset unusual Firefox-on-Android default style; see https://github.com/necolas/normalize.css/issues/214
   border: 1px solid @input-border;
   .border-radius(@input-border-radius);
-  box-shadow: inset 0 1px 1px rgba(0,0,0,.075);
+  .box-shadow(inset 0 1px 1px rgba(0,0,0,.075));
   transition: border-color ease-in-out .15s, box-shadow ease-in-out .15s;
 
   // Customize the `:focus` state to imitate native WebKit styles.

less/mixins.less

@@ -5,8 +5,8 @@
   border-radius: @radius;
 }
 
-.box-shadow(@shadow: 0 .1rem .2rem rgba(0,0,0,.1)) when (@enable-shadows = true) {
-  box-shadow: @shadow;
+.box-shadow(@shadow) when (@enable-shadows = true) {
+  box-shadow: @arguments;
 }
 
 

less/mixins/forms.less

@@ -20,10 +20,11 @@
   // Set the border and box shadow on specific inputs to match
   .form-control {
     border-color: @border-color;
-    box-shadow: inset 0 1px 1px rgba(0,0,0,.075); // Redeclare so transitions work
+    .box-shadow(inset 0 1px 1px rgba(0,0,0,.075)); // Redeclare so transitions work
     &:focus {
       border-color: darken(@border-color, 10%);
-      box-shadow: inset 0 1px 1px rgba(0,0,0,.075), 0 0 6px lighten(@border-color, 20%);
+      @shadow: inset 0 1px 1px rgba(0,0,0,.075), 0 0 6px lighten(@border-color, 20%);
+      .box-shadow(@shadow);
     }
   }
   // Set validation states also for addons
@@ -51,12 +52,12 @@
 //
 // Example usage: change the default blue border and shadow to white for better
 // contrast against a dark gray background.
-.form-control-focus(@color: @input-border-focus) {
-  @color-rgba: rgba(red(@color), green(@color), blue(@color), .6);
+.form-control-focus() {
   &:focus {
-    border-color: @color;
+    border-color: @input-border-focus;
     outline: 0;
-    box-shadow: inset 0 1px 1px rgba(0,0,0,.075), 0 0 8px @color-rgba;
+    @shadow: inset 0 1px 1px rgba(0,0,0,.075), 0 0 8px @input-box-shadow-focus;
+    .box-shadow(@shadow);
   }
 }
 

less/modals.less

@@ -53,7 +53,7 @@
   background-color: @modal-content-bg;
   border: 1px solid @modal-content-border-color;
   .border-radius(@border-radius-large);
-  box-shadow: 0 3px 9px rgba(0,0,0,.5);
+  .box-shadow(0 3px 9px rgba(0,0,0,.5));
   background-clip: padding-box;
   // Remove focus outline from opened modal
   outline: 0;
@@ -137,7 +137,7 @@
     margin: 30px auto;
   }
   .modal-content {
-    box-shadow: 0 5px 15px rgba(0,0,0,.5);
+    .box-shadow(0 5px 15px rgba(0,0,0,.5));
   }
 
   // Modal sizes

less/navbar.less

@@ -52,7 +52,7 @@
   padding-right: @navbar-padding-horizontal;
   padding-left:  @navbar-padding-horizontal;
   border-top: 1px solid transparent;
-  box-shadow: inset 0 1px 0 rgba(255,255,255,.1);
+  .box-shadow(inset 0 1px 0 rgba(255,255,255,.1));
   &:extend(.clearfix all);
   -webkit-overflow-scrolling: touch;
 
@@ -63,7 +63,7 @@
   @media (min-width: @grid-float-breakpoint) {
     width: auto;
     border-top: 0;
-    box-shadow: none;
+    .box-shadow(none);
 
     &.collapse {
       display: block !important;
@@ -248,7 +248,7 @@
       margin-top: 0;
       background-color: transparent;
       border: 0;
-      box-shadow: none;
+      .box-shadow(none);
       > li > a,
       .dropdown-header {
         padding: 5px 15px 5px 25px;
@@ -290,7 +290,7 @@
   padding: 10px @navbar-padding-horizontal;
   border-top: 1px solid transparent;
   border-bottom: 1px solid transparent;
-  box-shadow: inset 0 1px 0 rgba(255,255,255,.1), 0 1px 0 rgba(255,255,255,.1);
+  .box-shadow(~"inset 0 1px 0 rgba(255,255,255,.1), 0 1px 0 rgba(255,255,255,.1)");
 
   // Mixin behavior for optimum display
   .form-inline();
@@ -312,7 +312,7 @@
     margin-right: 0;
     padding-top: 0;
     padding-bottom: 0;
-    box-shadow: none;
+    .box-shadow(none);
   }
 }
 

less/popovers.less

@@ -14,10 +14,9 @@
   text-align: left; // Reset given new insertion method
   background-color: @popover-bg;
   background-clip: padding-box;
-  border: 1px solid @popover-fallback-border-color;
   border: 1px solid @popover-border-color;
-  border-radius: @border-radius-large;
-  box-shadow: 0 5px 10px rgba(0,0,0,.2);
+  .border-radius(@border-radius-large);
+  .box-shadow(0 5px 10px rgba(0,0,0,.2));
 
   // Overrides for proper insertion
   white-space: normal;

less/progress-bars.less

@@ -30,7 +30,7 @@
   margin-bottom: @line-height-computed;
   background-color: @progress-bg;
   .border-radius(@border-radius-base);
-  box-shadow: inset 0 1px 2px rgba(0,0,0,.1);
+  .box-shadow(inset 0 1px 2px rgba(0,0,0,.1));
 }
 
 // Bar of progress
@@ -43,7 +43,7 @@
   color: @progress-bar-color;
   text-align: center;
   background-color: @progress-bar-bg;
-  box-shadow: inset 0 -1px 0 rgba(0,0,0,.15);
+  .box-shadow(inset 0 -1px 0 rgba(0,0,0,.15));
   transition: width .6s ease;
 }
 
@@ -74,7 +74,7 @@
     min-width: 30px;
     background-color: transparent;
     background-image: none;
-    box-shadow: none;
+    .box-shadow(none);
   }
 }
 

less/theme.less

@@ -19,12 +19,13 @@
 .btn-warning,
 .btn-danger {
   text-shadow: 0 -1px 0 rgba(0,0,0,.2);
-  box-shadow: inset 0 1px 0 rgba(255,255,255,.15), 0 1px 1px rgba(0,0,0,.075);
+  @shadow: inset 0 1px 0 rgba(255,255,255,.15), 0 1px 1px rgba(0,0,0,.075);
+  .box-shadow(@shadow);
 
   // Reset the shadow
   &:active,
   &.active {
-    box-shadow: inset 0 3px 5px rgba(0,0,0,.125);
+    .box-shadow(inset 0 3px 5px rgba(0,0,0,.125));
   }
 }
 
@@ -77,9 +78,8 @@
 // Images
 // --------------------------------------------------
 
-.thumbnail,
 .img-thumbnail {
-  box-shadow: 0 1px 2px rgba(0,0,0,.075);
+  .box-shadow(0 1px 2px rgba(0,0,0,.075));
 }
 
 
@@ -111,11 +111,12 @@
   #gradient > .vertical(@start-color: lighten(@navbar-default-bg, 10%); @end-color: @navbar-default-bg);
   .reset-filter(); // Remove gradient in IE<10 to fix bug where dropdowns don't get triggered
   .border-radius(@navbar-border-radius);
-  box-shadow: inset 0 1px 0 rgba(255,255,255,.15), 0 1px 5px rgba(0,0,0,.075);
+  @shadow: inset 0 1px 0 rgba(255,255,255,.15), 0 1px 5px rgba(0,0,0,.075);
+  .box-shadow(@shadow);
 
   .navbar-nav > .active > a {
     #gradient > .vertical(@start-color: darken(@navbar-default-bg, 5%); @end-color: darken(@navbar-default-bg, 2%));
-    box-shadow: inset 0 3px 9px rgba(0,0,0,.075);
+    .box-shadow(inset 0 3px 9px rgba(0,0,0,.075));
   }
 }
 .navbar-brand,
@@ -130,7 +131,7 @@
 
   .navbar-nav > .active > a {
     #gradient > .vertical(@start-color: @navbar-inverse-bg; @end-color: lighten(@navbar-inverse-bg, 2.5%));
-    box-shadow: inset 0 3px 9px rgba(0,0,0,.25);
+    .box-shadow(inset 0 3px 9px rgba(0,0,0,.25));
   }
 
   .navbar-brand,
@@ -155,7 +156,8 @@
 // Common styles
 .alert {
   text-shadow: 0 1px 0 rgba(255,255,255,.2);
-  box-shadow: inset 0 1px 0 rgba(255,255,255,.25), 0 1px 2px rgba(0,0,0,.05);
+  @shadow: inset 0 1px 0 rgba(255,255,255,.25), 0 1px 2px rgba(0,0,0,.05);
+  .box-shadow(@shadow);
 }
 
 // Mixin for generating new styles
@@ -206,7 +208,7 @@
 
 .list-group {
   .border-radius(@border-radius-base);
-  box-shadow: 0 1px 2px rgba(0,0,0,.075);
+  .box-shadow(0 1px 2px rgba(0,0,0,.075));
 }
 .list-group-item.active,
 .list-group-item.active:hover,

less/variables.less

@@ -187,6 +187,7 @@
 @input-border-radius:            @border-radius-base;
 //** Border color for inputs on focus
 @input-border-focus:             #66afe9;
+@input-box-shadow-focus:         rgba(102,175,233,.6);
 
 //** Placeholder text color
 @input-color-placeholder:        @gray-light;