Check out example codes for "responsive html". It will help you in understanding the concepts better.

Code Example 1

<meta name="viewport" content="width=device-width, initial-scale=1.0">

Code Example 2

<div id="gallery">
            <div class="showcase-images">
                <div class="showcase-block">
            <img id="show-img" src="images/showcase/tabs.png" alt="Tabs">
            </div>
            </div>
            <nav>
            <ul id="main">
                <li id="tabs"><a href="#">Tab</a></li>
                <li id="login"><a href="#">Login</a></li>
                <li id="forum"><a href="#">Forum</a></li>
            </ul>
        </nav>
        </div>

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