This CSS Box Model Online Test helps you to Boost your Knowledge in PHP. In CSS box model online have a property padding-top which is used to adjust the padding from the top and the property value that is used to define the style for the bottom border of an element is "border-bottom-style." One more property value that is an overflow-x property which is used for the specification whether to clip the content, add a scroll bar, or display overflow content of a block-level element when it overflows at the left and right edges.