use browser defaults for focus outlines

This commit removes the styling that bootstrap overrides the normal
focus outlines with. The thin or missing outline was not accessible.

themes/default/files/resources/bootstrap/css/bootstrap.css

@@ -56,10 +56,6 @@ template {
 a {
   background-color: transparent;
 }
-a:active,
-a:hover {
-  outline: 0;
-}
 abbr[title] {
   border-bottom: 1px dotted;
 }
@@ -1118,11 +1114,6 @@ a:focus {
   color: #23527c;
   text-decoration: underline;
 }
-a:focus {
-  outline: thin dotted;
-  outline: 5px auto -webkit-focus-ring-color;
-  outline-offset: -2px;
-}
 figure {
   margin: 0;
 }
@@ -2643,13 +2634,6 @@ select[multiple],
 select[size] {
   height: auto;
 }
-input[type="file"]:focus,
-input[type="radio"]:focus,
-input[type="checkbox"]:focus {
-  outline: thin dotted;
-  outline: 5px auto -webkit-focus-ring-color;
-  outline-offset: -2px;
-}
 output {
   display: block;
   padding-top: 7px;
@@ -2687,11 +2671,6 @@ output {
 }
 .form-control:focus {
   border-color: #66afe9;
-  outline: 0;
-  -webkit-box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075), 0 0 8px rgba(102, 175, 233, 0.6);
-  -webkit-box-shadow: inset 0 1px 1px rgba(var(--opposite-background-colour), 0.075), 0 0 8px rgba(102, 175, 233, 0.6);
-  box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075), 0 0 8px rgba(102, 175, 233, 0.6);
-  box-shadow: inset 0 1px 1px rgba(var(--opposite-background-colour), 0.075), 0 0 8px rgba(102, 175, 233, 0.6);
 }
 .form-control::-moz-placeholder {
   color: #999999;
@@ -3152,31 +3131,12 @@ select[multiple].form-group-lg .form-control {
   -ms-user-select: none;
   user-select: none;
 }
-.btn:focus,
-.btn:active:focus,
-.btn.active:focus,
-.btn.focus,
-.btn:active.focus,
-.btn.active.focus {
-  outline: thin dotted;
-  outline: 5px auto -webkit-focus-ring-color;
-  outline-offset: -2px;
-}
 .btn:hover,
 .btn:focus,
 .btn.focus {
   color: #333333;
   text-decoration: none;
 }
-.btn:active,
-.btn.active {
-  outline: 0;
-  background-image: none;
-  -webkit-box-shadow: inset 0 3px 5px rgba(0, 0, 0, 0.125);
-  -webkit-box-shadow: inset 0 3px 5px rgba(var(--opposite-background-colour), 0.125);
-  box-shadow: inset 0 3px 5px rgba(0, 0, 0, 0.125);
-  box-shadow: inset 0 3px 5px rgba(var(--opposite-background-colour), 0.125);
-}
 .btn.disabled,
 .btn[disabled],
 fieldset[disabled] .btn {
@@ -3587,9 +3547,6 @@ tbody.collapse.in {
 .dropdown {
   position: relative;
 }
-.dropdown-toggle:focus {
-  outline: 0;
-}
 .dropdown-menu {
   position: absolute;
   top: 100%;