To ensure that the distance between lines of text is 1.5 times the size of the text, you can use the line-height property in CSS. You can set it to 150%, which is equivalent to 1.5 times the font size. Alternatively, you can use line-height with an em value, like 1.5em, which achieves the same effect.

The backface-visibility property in CSS is particularly useful when creating 3D transformations. When set to hidden, it prevents the back side of an element from being visible, which is essential for 3D transformations where the front and back of an element should not be visible simultaneously.

In Flexbox, the justify-content property is used to define how items are aligned along the main axis. It controls the distribution of space between and around items along the main axis and is commonly used to center items horizontally or vertically.

The "+" (Adjacent Sibling) combinator in CSS targets elements that are placed immediately after a specific element. It selects elements that share the same parent and are placed directly after the specified element.

The primary benefit of using tools like PostCSS in modern web development workflows is that it allows you to write CSS in JavaScript files, which enhances code modularity. PostCSS enables the use of CSS features that might not be available in traditional CSS, making it a powerful tool for optimizing and streamlining your styles.

In the BEM (Block Element Modifier) methodology, elements are represented with a single hyphen - connecting the block and element names. Therefore, the correct way to represent an element named "item" inside a block named "menu" is by using the class .menu-item.

To target devices with retina displays specifically, you can use the @media query and specify the min-device-pixel-ratio property. The value of 2 represents a typical retina display, where each CSS pixel corresponds to 2 physical device pixels. So, the correct option is @media (min-device-pixel-ratio: 2).

To use the attr() function to get the value of a data attribute in CSS, you should specify the attribute's name as an argument within attr(). For example, to retrieve the value of a data attribute named "data-value," you would use attr(data-value). You can then apply this value to a CSS property, such as content or a custom property.

The CSS property used to specify the number of times an animation should run is animation-iteration-count. This property allows you to control how many times an animation sequence repeats. If set to a specific number or "infinite," it determines the animation's iteration count.

To align the content of a grid item along the block (column) axis, you should use the 'align-content' property. 'align-content' aligns the items within the grid container along the block axis, such as centering them vertically. 'justify-content' and 'align-items' are used for the main and inline axes, respectively. 'align-self' is used to control the alignment of individual grid items.