The value of said property is adjusted automatically according to the content or the context of the element.
For example, a block-level element with height: auto will grow taller as it contains more text. For another example, a block element with margin: 0 auto will have the left and right margins increased until it becomes centered along the y-axis of the viewport.
It really depends on the property you give the value to, different properties behave differently depending on the content and context.
与恶龙缠斗过久,自身亦成为恶龙；凝视深渊过久,深渊将回以凝视…
