ui: use css variable to control the display of post author name (#302)

Author: XPoet

source/css/common/css-variables.styl

@@ -68,6 +68,7 @@
   // ==============================================================================================
   --post-title-align left         // Option values: left | center | right
   --post-author-avatar block      // Option values: none | block
+  --post-author-name flex         // Option values: none | flex
   --post-create-datetime flex     // Option values: none | flex
   --post-update-datetime flex     // Option values: none | flex
   --post-img-align 0 auto 0 0     // Option values: 0 auto 0 0 (left) | 0 auto (center) | 0 0 0 auto (right)

source/css/layout/post-content.styl

@@ -191,7 +191,7 @@ $spacer-padding = 2rem
           padding 0.2rem 0
 
           .author {
-            display flex
+            display var(--post-author-name)
             align-items center
             font-weight 600
             font-size 1.18rem