Final answer:
A media query with a condition of max-width: 300 means CSS rules will apply only if the viewport is 300 pixels wide or less, a technique used in responsive web design to enhance usability on different devices.
Step-by-step explanation:
A media query condition of max-width: 300 means that the CSS rules contained within that media query will only be applied to the document if the viewport (which is the visible area of a web page) is 300 pixels wide or less. This technique is a fundamental aspect of responsive web design, which ensures that web content renders well on a variety of devices and window sizes, from desktop monitors to mobile phones.
Here is a simple example of how a media query might look in a CSS stylesheet:
media only screen and (max-width: 300px) {
body {
background-color: lightblue;
}
}
In this case, the background color of the body element would change to light blue if the viewport is 300 pixels or narrower - an effective way to tailor the user experience for mobile or small-screen users.