In order to pass this test you must identify into your code all deprecated HTML tags listed above and replace them with proper tags or CSS rules. Some examples are given below:

• for <applet> tag, the equivalent tag is <object>
• for <center> tag, the alternative CSS property is text-align
• for <font> tag, the alternative CSS properties are font-family and font-size
• for <s>, <strike> and <u> tags, the alternative CSS property is text-decoration

In order to resolve this problem you are advised to:

• use gzip compression
• move all CSS style rules into a single, external and minified CSS file
• minify all JS files and,if possible, try combining them into a single external JS file
• use CSS layouts

Your two options for file compression are Deflate and GZIP.

• Deflate is an option which comes automatically with the Apache server and which is simple to set up.
• GZIP on the other hand needs to be installed and requires a bit more work to install. However, GZIP does achieve a higher compression rate and therefore might be a better choice if your website uses pages which have a lot of images or large file sizes.

Setting up file compression for your website will depend on which type of server you?re using for your website. Most likely, you?ll be using Apache, which means you can enable compression by adding a few deflate codes to your .htaccess file.

# compress text, html, javascript, css, xml:
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE application/x-javascript

For more advanced information regarding deflate you can check this Apache documentation.

Media queries allow you to style elements for specific devices (smartphones, tablets, desktop computers) by using attributes like width, height, resolution, aspect ratio, orientation or color. By using media queries, presentations can be tailored to a specific range of output devices without changing the content itself.
Example:

<link rel="stylesheet" media="screen and (min-width: 480px) and (max-width: 960px)" 
href="480-960.css" />
 
<!-- OR -->
@media screen and (min-width: 480px) and (max-width: 960px) {
    #header {
        display: none;
    }
}

An @media rule specifies the target media types of a set of statements. In the example above, we are specifying the media type screen. The max-width and min-width features are telling the browser that at any screen size larger than 480px, but smaller than 960px, hide any elements with id="header".

If you want that your webpage to be indexed by search engines, you have to remove the noindex meta tag from your HTML code.