#39, Finish columns shortcode, clean scss

assets/_markdown.scss

@@ -8,12 +8,12 @@ $block-border-radius: 0.15rem;
   h1, h2, h3, h4, h5 {
     font-weight: 400;
     line-height: 1.25;
+  }
 
-    // remove padding at the beginning of page
-    &> :first-child { 
-      margin-top: 0;
-      line-height: 1em;
-    }
+  // remove padding at the beginning of page
+  > :first-child {
+    margin-top: 0;
+    line-height: 1;
   }
 
   b, optgroup, strong {
@@ -72,4 +72,10 @@ $block-border-radius: 0.15rem;
       background: $gray-100;
     }
   }
+
+  hr {
+    height: $padding-1;
+    border: none;
+    background: $gray-200;
+  }
 }

assets/_shortcode.scss

@@ -1,10 +1,10 @@
 @import "variables";
 
 .markdown-inner {
-  :first-child {
+  > :first-child {
     margin-top: 0;
   }
-  :last-child {
+  > :last-child {
     margin-bottom: 0;
   }
 }
@@ -50,3 +50,9 @@
     display: block;
   }
 }
+
+.book-columns > {
+  div + div {
+    margin-left: $padding-16 * 2;
+  }
+}

assets/_utils.scss

@@ -34,14 +34,6 @@
   margin: 0 auto;
 }
 
-.mr-auto {
-  margin-right: auto;
-}
-
-.hide {
-  display: none;
-}
-
 @mixin fixed {
   position: fixed;
   top: 0;

assets/book.scss

@@ -149,21 +149,9 @@ ul.pagination {
   }
 }
 
-.book-git-footer {
-  display: flex;
-  margin-top: $padding-16;
-  font-size: $font-size-14;
-  align-items: baseline;
-
-  img {
-    width: $font-size-14;
-    vertical-align: bottom;
-  }
-}
-
 .book-footer {
   display: flex;
-  margin-top: $padding-16;
+  padding-top: $padding-16;
   font-size: $font-size-14;
   align-items: baseline;