Final answer:
Style sheets, like CSS, separate formatting from content, allowing for a consistent design across a website. They simplify website maintenance and updates by centralizing style rules, such as changing the color of all headings with a single line of code.
Step-by-step explanation:
Style sheets solve the issue of separating formatting code from web page content. By using a cascading style sheet (CSS), web designers and developers can create a consistent look and feel across multiple pages of a website without having to write formatting code for each individual piece of content. This not only saves time but also makes maintenance and updates to the website much easier.
An example of this is when a web developer wants to change the font color of all the headings in a website. Instead of changing the color for each heading individually within the HTML code, the developer can simply change one line in the CSS file. This line might look something like h1 { color: blue; }, which would apply blue color to all level-one headings (h1) on the web pages that the style sheet is linked to.