Fix code style of SCSS files

_sass/addon/commons.scss

@@ -649,9 +649,6 @@ $sidebar-display: "sidebar-display";
 
   #avatar {
     > a {
-      &:hover {
-        border-color: white;
-      }
       display: block;
       width: 6rem;
       height: 6rem;
@@ -662,6 +659,10 @@ $sidebar-display: "sidebar-display";
       -webkit-transition: border-color 0.35s ease-in-out;
       -moz-transition: border-color 0.35s ease-in-out;
       transition: border-color 0.35s ease-in-out;
+
+      &:hover {
+        border-color: white;
+      }
     }
 
     img {
@@ -806,11 +807,6 @@ $sidebar-display: "sidebar-display";
       vertical-align: middle;
     }
 
-    i {
-      line-height: 1.75rem; // default line-height in body
-      vertical-align: middle;
-    }
-
     #mode-toggle-wrapper {
       @extend %icon;
 

_sass/addon/syntax.scss

@@ -187,7 +187,7 @@ div {
   span {
     padding-left: 0.6rem;
 
-    &:after {
+    &::after {
       content: attr(text-data);
       margin-left: 0.3rem;
       font-size: 0.85rem;
@@ -202,7 +202,6 @@ div {
 
   }
 
-
   // clipboard
   button {
     border: 1px solid var(--code-header-bg);

_sass/colors/dark-typography.scss

@@ -100,13 +100,12 @@
   nav[data-toggle=toc] .nav-link.active,
   nav[data-toggle=toc] .nav-link.active:focus,
   nav[data-toggle=toc] .nav-link.active:hover,
-  nav[data-toggle=toc] .nav>li>a:focus,
+  nav[data-toggle=toc] .nav > li > a:focus,
-  nav[data-toggle=toc] .nav>li>a:hover {
+  nav[data-toggle=toc] .nav > li > a:hover {
     color: var(--toc-highlight) !important;
     border-left-color: var(--toc-highlight) !important;
   }
 
-
   /* categories */
   .categories.card,
   .list-group-item {

_sass/layout/post.scss

@@ -158,7 +158,6 @@ nav[data-toggle=toc] {
   }
 }
 
-
 /* --- Related Posts --- */
 
 #related-posts {