php stormを使ってphpファイル内にHTMLコードを記入する方法について

phpStormを使い始めたphp初学者です。
phpStorm内にheader.phpというファイルを作成し、その中にheader部分に相当するHTMLを記入したところエラーが頻発しております。
特殊な記述はしておらず、以下のようにシンプルな構文でさえエラーとなってしまします。
エラーの内容は
Undefined constant DOCTYPE less... (⌘F1)
Inspection info: Declaration of referenced constant is not found in built-in library and project files.
Undefined constant html less... (⌘F1)
Inspection info: Declaration of referenced constant is not found in built-in library and project files.
Undefined constant href less... (⌘F1)
Inspection info: Declaration of referenced constant is not found in built-in library and project files
Expected: semicolon

など、少しのHTMLを記述することも許されない状況です。

もしphpStormにお詳しいかたいらっしゃいましたらお知恵を拝借できますと幸いです。

<?php
/**
 * Created by PhpStorm.
 */
<!DOCTYPE html>
<!--[if lt IE 7]>      <html class="no-js lt-ie9 lt-ie8 lt-ie7"> <![endif]-->
<!--[if IE 7]>         <html class="no-js lt-ie9 lt-ie8"> <![endif]-->
<!--[if IE 8]>         <html class="no-js lt-ie9"> <![endif]-->
<!--[if gt IE 8]><!--> <html class="no-js"> <!--<![endif]-->
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
    <title>Home | Nova</title>
    <meta name="description" content="">
    <meta name="viewport" content="width=device-width">

    <link rel="stylesheet" href="css/bootstrap.min.css">
    <link rel="stylesheet" href="css/bootstrap-responsive.min.css">
    <link rel="stylesheet" href="css/font-awesome.min.css">
    <link rel="stylesheet" href="css/main.css">
    <link rel="stylesheet" href="css/sl-slide.css">

    <script src="js/vendor/modernizr-2.6.2-respond-1.1.0.min.js"></script>

    <!-- Le fav and touch icons -->
    <link rel="shortcut icon" href="images/ico/favicon.ico">
    <link rel="apple-touch-icon-precomposed" sizes="144x144" href="images/ico/apple-touch-icon-144-precomposed.png">
    <link rel="apple-touch-icon-precomposed" sizes="114x114" href="images/ico/apple-touch-icon-114-precomposed.png">
    <link rel="apple-touch-icon-precomposed" sizes="72x72" href="images/ico/apple-touch-icon-72-precomposed.png">
    <link rel="apple-touch-icon-precomposed" href="images/ico/apple-touch-icon-57-precomposed.png">
</head>

<body>

    <!--Header-->
    <header class="navbar navbar-fixed-top">
        <div class="navbar-inner">
            <div class="container">
                <a class="btn btn-navbar" data-toggle="collapse" data-target=".nav-collapse">
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                </a>
                <a id="logo" class="pull-left" href="index.html"></a>
                <div class="nav-collapse collapse pull-right">
                    <ul class="nav">
                        <li class="active"><a href="index.html">Home</a></li>
                        <li><a href="about-us.html">About Us</a></li>
                        <li><a href="services.html">Services</a></li>
                        <li><a href="portfolio.html">Portfolio</a></li>
                        <li class="dropdown">
                            <a href="#" class="dropdown-toggle" data-toggle="dropdown">Pages <i class="icon-angle-down"></i></a>
                            <ul class="dropdown-menu">
                                <li><a href="career.html">Career</a></li>
                                <li><a href="blog-item.html">Blog Single</a></li>
                                <li><a href="faq.html">FAQ</a></li>
                                <li><a href="pricing.html">Pricing</a></li>
                                <li><a href="404.html">404</a></li>
                                <li><a href="typography.html">Typography</a></li>
                                <li><a href="registration.html">Registration</a></li>
                                <li class="divider"></li>
                                <li><a href="privacy.html">Privacy Policy</a></li>
                                <li><a href="terms.html">Terms of Use</a></li>
                            </ul>
                        </li>
                        <li><a href="blog.html">Blog</a></li>
                        <li><a href="contact-us.html">Contact</a></li>
                        <li class="login">
                            <a data-toggle="modal" href="#loginForm"><i class="icon-lock"></i></a>
                        </li>
                    </ul>
                </div><!--/.nav-collapse -->
            </div>
        </div>
    </header>
    <!-- /header -->