Test your knowledge: CSS Declarations

Review

1. Which of these is a complete, valid CSS declaration?

   A declaration is a property name, a colon, a value, and a semicolon. The equals sign belongs elsewhere, and leaving out the colon leaves the browser two words it cannot divide into property and value.
2. What is the semicolon at the end of a declaration actually doing?

   Each declaration is terminated by a semicolon, allowing several properties to contribute to the same style rule. The very last one before the closing brace can technically drop it, and every style written without it is a merge conflict waiting for a rainy day.
3. A rule says display: blue;. What happens?

   A property does not accept an arbitrary value. display speaks in keywords like block and flex, not colors, so that one declaration is invalid and ignored. When something silently refuses to work, the property's value grammar is one of the first places to look.
4. Inside one style rule, what is the division of labor?

   The selector identifies the elements a rule applies to; the declarations then specify what should change about those matches. Mixing the two up is the fastest way to misread a stylesheet you did not write.
5. How many declarations can one declaration block hold?

   A declaration block can contain multiple declarations, each terminated by a semicolon, so color, margin, and font-size can all contribute to one rule. The same property appearing twice is legal too, and the last one wins.