Fix friend links

views/index.ejs

@@ -177,9 +177,9 @@
         <p><%- syzoj.config.announcement %></p>
         <% } %>
       </div>
-      <% if (links) { %>
+      <% if (typeof links !== 'undefined' && links) { %>
       <h4 class="ui top attached block header font-content">友情链接</h4>
-      <div class="ui bottom attached <% if (!syzoj.config.announcement) { %>center aligned <% } %>segment">
+      <div class="ui bottom attached segment">
         <ul style="margin: 0; padding-left: 20px; ">
           <% for (let link of links) { %>
             <li><a href="<%= link.url %>"><%= link.title %></a></li>