diff --git a/admin/css/style.css b/admin/css/style.css
index 0e558ca5..a7434890 100644
--- a/admin/css/style.css
+++ b/admin/css/style.css
@@ -1176,7 +1176,9 @@ a.operate-reply {
   padding: 5px 20px;
   border: 1px solid #F3F3F0;
   border-width: 1px 0 0 1px;
-  height: 100%;
+  height: -moz-calc(100% - 52px);
+  height: -webkit-calc(100% - 52px);
+  height: calc(100% - 52px);
   background: #F6F6F3;
   overflow: auto; }
   .fullscreen #wmd-preview code, .fullscreen #wmd-preview pre {
diff --git a/admin/scss/components/_editor.scss b/admin/scss/components/_editor.scss
index 503932da..a42e45a2 100644
--- a/admin/scss/components/_editor.scss
+++ b/admin/scss/components/_editor.scss
@@ -119,7 +119,8 @@
     padding: 5px 20px;
     border: 1px solid #F3F3F0;
     border-width: 1px 0 0 1px;
-    height: 100%;
+    // height: 100%;
+    @include calc(height, "100% - 52px");
     background: #F6F6F3;
     overflow: auto;
     code, pre {
diff --git a/admin/scss/style.scss b/admin/scss/style.scss
index 1baf05bf..b9aa29c9 100644
--- a/admin/scss/style.scss
+++ b/admin/scss/style.scss
@@ -9,6 +9,7 @@
 */
 
 @import "compass";
+@import "mixin";
 
 /**
 * Typecho 全局样式