[Plugin: WP Code Prettify] HTML Syntax Not Showing. CSS Syntax Unstyled.

I cannot get Prettify to work with HTML syntax at all and CSS syntax appears but is unstyled. Can someone please help me?

HTML:
1. I’ve installed “WP Code Prettify”
2. I placed the following syntax into my php file:

<pre class="prettyprint">
<input type="text" id="input-field" size="20" spellcheck="false">
</pre>

HTML result: An actual input field instead of the browser showing the code/syntax.

—-

CSS:
1. I’ve installed “WP Code Prettify”
2. I placed the following syntax into my php file:

<pre class="prettyprint">
#input {
padding: 0 0 30px 0;
border-bottom: 1px solid #e1e1e1;
}
</pre>

CSS result: The CSS syntax shows but it is unstyled.

I cannot get Prettify to work with HTML syntax. Can someone please help me?

http://wordpress.org/extend/plugins/wp-code-prettify/