Remove purecss dependency and replace with flexbox

layouts/partials/docs/header.html

@@ -1,6 +0,0 @@
-<label for="nav-control">
-  <img src="/svg/menu.svg" />
-</label>
-<h3>
-  <a href="{{ .Site.BaseURL }}">{{ .Site.Title }}</a>
-</h3>

layouts/partials/docs/html-head.html

@@ -3,10 +3,7 @@
 <title>{{- template "title" .  }} | {{ .Site.Title -}}</title>
 
 <link href="https://fonts.googleapis.com/css?family=Roboto+Mono|Roboto:300,400,700" rel="stylesheet">
-<link rel="stylesheet" href="https://unpkg.com/purecss@1.0.0/build/base-min.css">
-<link rel="stylesheet" href="https://unpkg.com/purecss@1.0.0/build/grids-min.css">
-<link rel="stylesheet" href="https://unpkg.com/purecss@1.0.0/build/grids-responsive-min.css">
-
+<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/normalize/8.0.0/normalize.min.css">
 
 {{ $styles := resources.Get "styles.scss" | resources.ToCSS | resources.Minify | resources.Fingerprint }}
 <link rel="stylesheet" href="{{ $styles.Permalink }}">

layouts/partials/docs/menu-filetree.html

@@ -8,7 +8,7 @@
 {{ define "book-section" }} <!-- Single section of menu (recursive) -->
   <ul>
     {{ range .Section.Sections }}
-    <li {{- if .Params.bookrootsection}} class="root-section" {{ end }}>
+    <li {{- if .Params.bookrootsection}} class="section" {{ end }}>
       {{- if .Content -}}
         {{ template "book-page-link" (dict "Page" . "CurrentPage" $.CurrentPage) }}
       {{- else -}}

layouts/partials/docs/nav-brand.html

@@ -1,3 +0,0 @@
-<h2 class="book-brand">
-  <a href="{{ .Site.BaseURL }}">{{ .Site.Title }}</a>
-</h2>