diff --git a/css/area_nav-breadcrumb.less b/css/area_nav-breadcrumb.less
index 1c64090..e7be950 100755
--- a/css/area_nav-breadcrumb.less
+++ b/css/area_nav-breadcrumb.less
@@ -95,7 +95,7 @@
             > a {
                 display: block;
                 width: auto;
-                min-height: 2em;
+                min-height: @toggle-size;
                 border: 1px solid @color-border;
                 border-radius: @border-radius;
                 color: @color-nav;
@@ -107,7 +107,6 @@
                 .btn-prefix ();
                 .icon-clipboard();
 
-                min-height: 20px;
                 font-size: 1.2rem;
                 line-height: 1;
             }
diff --git a/css/area_nav-usertools.less b/css/area_nav-usertools.less
index fbcf781..1debbda 100755
--- a/css/area_nav-usertools.less
+++ b/css/area_nav-usertools.less
@@ -28,7 +28,7 @@
             > a {
                 display: block;
                 width: auto;
-                min-height: 2em;
+                min-height: @toggle-size;
                 border: 1px solid @color-border;
                 border-radius: @border-radius;
                 color: @color-nav;
diff --git a/css/base.less b/css/base.less
index d6435a7..79eae35 100755
--- a/css/base.less
+++ b/css/base.less
@@ -54,9 +54,11 @@
 @very-small-spacing: .2rem;
 
 @grid:               @margin-small;
+@toggle-size:        1.75rem;
 
 @transition: ease-out .30s;
 
+
 /* + + +  for programmers customizing  + + + */
 @fix_border-radius:        3px;
 @toggle-showsidebar_width: 3.07rem;       // shown sidebar after toggle
@@ -92,6 +94,7 @@
 @font-size-head2: @font-size-default + (@font-scale-factor * 4);
 @font-size-head1: @font-size-default + (@font-scale-factor * 5);
 
+
 /* + + + + + + + + + + + + + + + + + + + + + + + + + + */
 /* breakpoints */
 
diff --git a/css/base_mixins.less b/css/base_mixins.less
index 91645bb..ab11712 100755
--- a/css/base_mixins.less
+++ b/css/base_mixins.less
@@ -142,7 +142,7 @@
 
 
 /* + + + + +  small icon-buttons (breadcrumb, page-header)  + + + + + */
-.btn-usertools-wrapper(@elem:2em) {
+.btn-usertools-wrapper(@elem:@toggle-size) {
     display: inline-block;
     min-height: @elem;
     min-width: @elem;
@@ -194,26 +194,11 @@
     margin-top: .3rem;
 }
 
-
-.btn-default-size() {
-    height: 1rem;
-    width: 1rem;
-    min-height: 1.2em;
-    min-width: 1.4em;
-}
-
-.btn-default-height() {
-    height: 1rem;
-    min-height: 1.2em;
-    min-width: 1.4em;
-}
-
 .hide-text-show-before(){
     display: inline-block;
     overflow: hidden;
     white-space: nowrap;
     text-indent: -9999px;
-    .btn-default-size();
 
     &::before{
         text-indent: 0;
@@ -226,7 +211,6 @@
     }
 }
 
-
 .hide-text-show-after() {
     display: inline-block;
     overflow: hidden;
diff --git a/css/plugins/bureaucracy.less b/css/plugins/bureaucracy.less
index 1fcb7ed..0c2f12d 100755
--- a/css/plugins/bureaucracy.less
+++ b/css/plugins/bureaucracy.less
@@ -42,7 +42,7 @@
         select {
             float: left;
             width: 50%;
-            //min-height: 2em;
+            //min-height: @toggle-size;
             text-align: left;
             padding: .1em .2em;
         }