Topic 1: Creating a responsive web design is about the creation of web pages that appear to look good on all of their devices.

When you use a responsive web design it will automatically adjust for a user’s different screen sizes and viewports. It uses HTML and CSS to automatically resize, shrink, hide, or enlarge a website to make it look good on all devices including desktops, tablets, and phones. To create the responsive website, you must add the following <meta>. It must include a viewport and content, which determines the device's width.

Topic 2: You can also create images that are responsive images which scale nicely in order to fit any size browser.

If the CSS width property is set to 100 percent, the image will be responsive and thus scale up and down. The image can also be scaled to be larger than its initial size. If this is the case, the max-width property should be used instead. When this property is set to 100%, the image will scale down if it has to, but it will never scale up to be larger than the original size of the image.

Topic 3: There are also items known as CSS Media Queries which can be found in CSS.

The @media rule, which was introduced in CSS2, makes it possible to define different style rules for other media types that are used. Media queries found in CSS3 extend the CSS2 media types. Instead of looking for a specific type of device, they look at the general capability of the device. Media queries can be used in CSS to check many things. These include: width and height of the viewport, the orientation of the viewport (landscape or portrait), and the resolution. A media query consists of a media type and can contain one or more media features, which are either true or false.