Is there a reason why the page is scrolling right to left unnecessarily?
Here's the current code on Codepen for reference - some adjustments had to be made to the body margin and padding to avoid a gap between the footer and the end of the page.
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Temp Test</title>
<link rel="stylesheet" type="text/css" href="css/stylesheet.css">
</head>
<body>
<div class="header">
<div class="header-content">
<h2>Notify</h2>
<p>A great new free psd theme to showcase your new application.</p>
<button><img src="http://i.imgur.com/zE3sKOv.png" alt="Windows"></button>
<button><img src="http://i.imgur.com/vR9AXQJ.png" alt="apple"></button>
<button><img src="http://i.imgur.com/caCQeE7.png" alt="Android"></button>
</div>
</div>
<div class="features">
<div class="features-content_1">
<div><img src="http://i.imgur.com/hCRBOyI.png" alt="gear">
<h2>Editable Theme</h2>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse fringilla fringilla.</p>
</div>
</div>
<div class="features-content_1">
<div><img src="http://i.imgur.com/hCRBOyI.png" alt="gear">
<h2>Editable Theme</h2>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse fringilla fringilla.</p>
</div>
</div>
<div class="features-content_1">
<div><img src="http://i.imgur.com/hCRBOyI.png" alt="gear">
<h2>Editable Theme</h2>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse fringilla fringilla.</p>
</div>
</div>
</div>
<div class="get-notified">
<div class="text">
<h3>Get Notified Of Any Updates!</h3>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse fringilla fringilla nisl congue congue. Maecenas nec condimentum libero, at elementum mauris. Phasellus eget nisi dapibus, ultricies nisl at, hendrerit risusuis ornare luctus id
sollicitudin ante lobortis at.</p>
<form>
<span class="email"><input type="email" placeholder="Email Adress" style=" text-align: center;
border: none;
border-radius: 8px;
width: 260px;
height: 31px;
float:left;" /></span>
</form>
<input type="submit" name="Notify" style="cursor:pointer;border:none;background-color: #2ecc71;margin-left: -20px;/* height: 50px; */border-left: 5px;border-top-right-radius: 8px;border-bottom-right-radius: 8px;height: 33px;" />
</div>
<div class="video-notified">
<iframe width="600" height="300" src="https://www.youtube.com/embed/l9VFg44H2z8" frameborder="0" allowfullscreen style="
float: right;
width: 400px;
height: 230px;
padding-top: 50px;
padding-right: 95px;
"></iframe>
</div>
</div>
<div class="end">
<div class="testi">
<p>“Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris interdum velit vitae nulla molestie eu commodo nulla dapib us. Donec id sollicitudin urna. Integer at dui ac leo fermentum varius eleifend ut.”</p>
<h4>Jane Hunt</h4>
</div>
<div class="get-social">
<img src="https://placeholdit.imgix.net/~text?txtsize=33&txt=1152%C3%9760&w=1152&h=60">
<h3>Say Hi & Get in Touch</h3>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit suspendisse.</p>
<a href="https://twitter.com/@_black_me_" target="_blank"><img src="http://i.imgur.com/mgWJfui.png" alt="twitter"></a>
<a href="http://www.facebook.com/abdoo.sorcerer" target="_blank"><img src="http://i.imgur.com/G4YerKE.png" alt="facebook"></a>
<a href="#"><img src="http://i.imgur.com/8gpGXZD.png" alt="youtube"></a>
<a href="#"><img src="http://i.imgur.com/lADlqJt.png" alt="linked-in"></a>
</div>
</div>
</body>
<footer>
</footer>
</html>