Fix btn link hover and tweak dropdown border/shadows

docs/assets/css/bootstrap.css

@@ -2224,10 +2224,10 @@ table th[class*="span"] {
   list-style: none;
   background-color: #ffffff;
   border: 1px solid #ccc;
-  border: 1px solid rgba(0, 0, 0, 0.2);
+  border: 1px solid rgba(0, 0, 0, 0.15);
   border-radius: 4px;
-  -webkit-box-shadow: 0 5px 10px rgba(0, 0, 0, 0.2);
-          box-shadow: 0 5px 10px rgba(0, 0, 0, 0.2);
+  -webkit-box-shadow: 0 6px 12px rgba(0, 0, 0, 0.175);
+          box-shadow: 0 6px 12px rgba(0, 0, 0, 0.175);
   -webkit-background-clip: padding-box;
      -moz-background-clip: padding-box;
           background-clip: padding-box;
@@ -2575,11 +2575,16 @@ fieldset[disabled] .btn-link {
           box-shadow: none;
 }
 
+.btn-link,
+.btn-link:hover,
+.btn-link:active {
+  border-color: transparent;
+}
+
 .btn-link {
   font-weight: normal;
   color: #428bca;
   cursor: pointer;
-  border-color: transparent;
   border-radius: 0;
 }
 
@@ -3345,7 +3350,7 @@ fieldset[disabled] .navbar .btn-navbar {
   border-right: 7px solid transparent;
   border-bottom: 7px solid #ccc;
   border-left: 7px solid transparent;
-  border-bottom-color: rgba(0, 0, 0, 0.2);
+  border-bottom-color: rgba(0, 0, 0, 0.15);
   content: '';
 }
 
@@ -3365,7 +3370,7 @@ fieldset[disabled] .navbar .btn-navbar {
   bottom: -7px;
   border-top: 7px solid #ccc;
   border-bottom: 0;
-  border-top-color: rgba(0, 0, 0, 0.2);
+  border-top-color: rgba(0, 0, 0, 0.15);
 }
 
 .navbar-fixed-bottom .nav > li > .dropdown-menu:after {

less/buttons.less

@@ -183,11 +183,15 @@ fieldset[disabled] .btn-link {
   background-image: none;
   .box-shadow(none);
 }
+.btn-link,
+.btn-link:hover,
+.btn-link:active {
+  border-color: transparent;
+}
 .btn-link {
   color: @link-color;
   font-weight: normal;
   cursor: pointer;
-  border-color: transparent;
   border-radius: 0;
 }
 .btn-link:hover {

less/dropdowns.less

@@ -49,7 +49,7 @@
   border: 1px solid #ccc; // IE8 fallback
   border: 1px solid @dropdown-border;
   border-radius: @border-radius-base;
-  .box-shadow(0 5px 10px rgba(0,0,0,.2));
+  .box-shadow(0 6px 12px rgba(0,0,0,.175));
   .background-clip(padding-box);
 
   // Aligns the dropdown menu to right

less/variables.less

@@ -112,7 +112,7 @@
 // -------------------------
 
 @dropdown-background:            #fff;
-@dropdown-border:                rgba(0,0,0,.2);
+@dropdown-border:                rgba(0,0,0,.15);
 @dropdown-divider-top:           #e5e5e5;
 @dropdown-divider-bottom:        #fff;