The ::after pseudo-element in CSS is used to insert content after the selected element. It is commonly used for adding decorative elements or additional content after an existing element. By using the ::after pseudo-element and specifying the content property, you can dynamically generate and place content after an element without modifying the HTML structure.

The mask-composite property in CSS is used to determine how a mask image should be combined with the element it's applied to. It's used to control the blending mode of the mask image with the element, allowing for various effects.

To make a row of items wrap onto the next line when there isn't enough space in a Flexbox layout, you would adjust the flex-direction property to "column" (for vertical stacking) and flex-wrap to "wrap." This allows the items to stack vertically when space is limited.

To pause an animation before it begins or between iterations, you should use the animation-play-state property. By setting it to paused, you can temporarily halt the animation. This is useful for creating interactive animations and controlling when they start or stop.

In terms of specificity, ID selectors have the highest priority. They are more specific than class selectors, element selectors, and universal selectors, and styles defined using ID selectors will override styles defined with lower-specificity selectors.

In CSS, the min() function returns the minimum value among its arguments, while the max() function returns the maximum value. These two functions are complementary but serve different purposes. The clamp() function, on the other hand, allows you to set a value within a range, ensuring it stays between the minimum and maximum values provided as arguments.

Applying the grayscale(100%) filter to a colored image will turn the image completely black. The grayscale filter in CSS converts the image to grayscale, and when you specify 100%, it means full grayscale, which results in a black and white image with all color information removed.

In CSS, the font-weight property is used to control the thickness of the text. The value "normal" corresponds to the standard or regular font weight, making it neither bolder nor lighter.

In CSS, when a variable is not set or its value is invalid, it will return the default value. This default value varies depending on the property. For example, the default value for the font-size property is often 16 pixels.

The font-family property in CSS is used to specify the font family for an element. This property allows you to define the typeface or font you want to use for text within that element, which can greatly affect the visual style of your website.