Restyle blockquotes (#32)

* Restyle blockquotes

- Entire block is formatted as a unit when you do:

  > paragraph 1
  >
  > paragraph 2

- Quotes are no longer automatically inserted around each paragraph of a blockquote
- Style is changed from dark background blob to a thick gray line on the left

* Use variable instead of fixed color

assets/css/styles.css

@@ -253,21 +253,14 @@ figcaption {
 }
 
 blockquote {
-    margin: 10px;
+    border-left: 6px solid var(--colorSecondary);
+    margin-top: 1rem;
+    margin-bottom: 1rem;
 }
 
 blockquote p {
-    padding: 15px;
-    background: var(--colorSecondary);
-    border-radius: 5px;
-}
-
-blockquote p::before {
-    content: '\201C';
-}
-
-blockquote p::after {
-    content: '\201D';
+    padding-left: 1rem;
+    padding-right: 1rem;
 }
 
 @media only screen and (max-width: 850px) {