Users visit from phones, tablets, laptops and TVs. A responsive page adapts its layout to the screen size. Three ingredients: the viewport meta tag, flexible layouts, and media queries.
Step 0: viewport tag (already in our template; without it phones show a shrunken desktop page):
HTML
<meta name='viewport' content='width=device-width, initial-scale=1.0'>Flexible images:
CSS
img { max-width: 100%; height: auto; }