Fix default box solid color issue

build/less/boxes.less

@@ -84,7 +84,7 @@
 
     // Box color variations
     &.box-default {
-      .box-solid-variant(@gray, #444);
+      .box-solid-variant(@gray-lte, #444);
     }
     &.box-primary {
       .box-solid-variant(@light-blue);

dist/css/AdminLTE.css

@@ -1607,12 +1607,12 @@ a:focus {
   background: rgba(0, 0, 0, 0.1);
 }
 .box.box-solid.box-default {
-  border: 1px solid #555555;
+  border: 1px solid #d2d6de;
 }
 .box.box-solid.box-default > .box-header {
   color: #444444;
-  background: #555555;
-  background-color: #555555;
+  background: #d2d6de;
+  background-color: #d2d6de;
 }
 .box.box-solid.box-default > .box-header a,
 .box.box-solid.box-default > .box-header .btn {

dist/css/alt/AdminLTE-without-plugins.css

@@ -1607,12 +1607,12 @@ a:focus {
   background: rgba(0, 0, 0, 0.1);
 }
 .box.box-solid.box-default {
-  border: 1px solid #555555;
+  border: 1px solid #d2d6de;
 }
 .box.box-solid.box-default > .box-header {
   color: #444444;
-  background: #555555;
-  background-color: #555555;
+  background: #d2d6de;
+  background-color: #d2d6de;
 }
 .box.box-solid.box-default > .box-header a,
 .box.box-solid.box-default > .box-header .btn {

starter.html

@@ -293,7 +293,7 @@ desired effect
     <section class="content">
 
       <!-- Your Page Content Here -->
-     
+
     </section>
     <!-- /.content -->
   </div>