This page rounds up questions and answers, and other material on the MDN site that can help you to solve common CSS problems.
Shadows can be added to boxes with the box-shadow property. This tutorial explains how it works and shows an example.
The object-fit property provides different ways to fit an image into a box which has a different aspect ratio, and you can find out how to use them in this tutorial.
A rundown of the different properties that might be useful when styling boxes using CSS.
The opacity property and color values with an alpha channel can be used for this; find out which one to use when.
Shadows can be added to text with the text-shadow property. This tutorial explains how it works and shows an example.
Find out how to target the first line of text in a paragraph with the ::first-line pseudo-element.
Find out how to target the first paragraph with the :first-child pseudo-class.
Combinators can help you to precisely target elements based on where they are in the document; this tutorial explains how to use them to apply CSS to a paragraph only if it immediately follows a heading.
Centering an item inside another box horizontally and vertically used to be tricky, however flexbox now makes it simple.
Note: We have a cookbook dedicated to CSS Layout solutions, with fully working examples and explanations of common layout tasks. Also check out Practical Positioning Examples, which shows how you can use positioning to create a tabbed info box, and a sliding hidden panel.