Set code font and remove unused palette

Author: velopert

src/components/post/PostContent.tsx

@@ -1,7 +1,6 @@
 import * as React from 'react';
 import styled from 'styled-components';
 import MarkdownRender from '../common/MarkdownRender';
-import palette from '../../lib/styles/palette';
 import PostHtmlContent from './PostHtmlContent';
 
 const PostContentBlock = styled.div`

src/index.css

@@ -1,5 +1,3 @@
-@import url('https://fonts.googleapis.com/css?family=Fira+Mono');
-
 body {
   margin: 0;
   padding: 0;
@@ -17,7 +15,7 @@ body {
 }
 
 code {
-  font-family: source-code-pro, Menlo, Monaco, Consolas, 'Courier New',
+  font-family: 'Fira Mono', source-code-pro, Menlo, Monaco, Consolas, 'Courier New',
     monospace;
 }