override variables of bootstrap

src/client/styles/scss/_override-bootstrap-variables.scss

@@ -58,3 +58,11 @@ $input-bg-disabled:              $btn-default-bgcolor;
 
 //** `<input>` border color
 $input-border:                   $border;
+
+//== Navbar
+$navbar-default-color: #777;
+$navbar-default-bg: #f8f8f8;
+$navbar-default-border: darken($navbar-default-bg, 6.5%);
+
+//== card
+$card-border-radius: 0;

src/client/styles/scss/_override-bootstrap.scss

@@ -16,18 +16,18 @@
 // card (substitute panel of bootstrap3)
 .card {
   margin-bottom: 20px;
-  border-radius: 0;
+  border-radius: $card-border-radius;
 }
 
 .card-header {
   padding: 7px 15px;
   font-weight: 700;
   text-transform: none;
-  border-radius: 0;
+  border-radius: $card-border-radius;
 }
 
 .card-header:first-child {
-  border-radius: 0;
+  border-radius: $card-border-radius;
 }
 
 // Well (substitute Well of bootstrap3)

src/client/styles/scss/_variables-bootstrap.scss

@@ -56,11 +56,6 @@ $navbar-padding-y: 0;
 $navbar-brand-padding-y: 0;
 $navbar-nav-link-padding-x: 1rem;
 
-//== Navbar(variables of bootstrap3)
-$navbar-default-color: #777 !default;
-$navbar-default-bg: #f8f8f8 !default;
-$navbar-default-border: darken($navbar-default-bg, 6.5%) !default;
-
 //== Dropdowns
 $dropdown-border-radius: 0;