Update 2 files

- /_layouts/post.html
- /search.html

search.html

@@ -6,7 +6,7 @@ title: 搜索
 <h1>搜索</h1>
 <form action="https://www.google.com/search">
 <input type="hidden" name="as_sitesearch" value="mabbs.github.io" />
-<p><input name="q" type="text" id="search-input" placeholder="Search blog posts.." /> <!--[if !IE]> --><img src="/images/loading.svg" alt="Loading..." id="search-loading" style="width:22px;vertical-align: bottom" /><!-- <![endif]--> <input type="submit" value="谷歌搜索" style="margin-left: 5px;" /></p>
+<p><center><input name="q" type="text" id="search-input" placeholder="Search blog posts.." /> <!--[if !IE]> --><img src="/images/loading.svg" alt="Loading..." id="search-loading" style="width:22px;vertical-align: bottom" /><!-- <![endif]--> <input type="submit" value="谷歌搜索" style="margin-left: 5px;" /></center></p>
 </form>
 <ul id="results-container"></ul>
 <!--[if !IE]> -->