The tutorial provides an exploration of various CSS techniques for creating a double-border effect on webpage elements, differentiating between the use of borders and outlines, and comparing the inset and outset properties. It highlights six CSS methods—border-style, outline, pseudo-element, box-shadow, background-clip, and linear-gradient—to achieve the double-border styling, explaining each method's implementation and visual outcome. The tutorial emphasizes understanding the distinctions between CSS border and outline properties, noting that borders are part of the element's box model while outlines are not, and discusses their different impacts on layout and design emphasis. Additionally, it touches on styling with CSS inset and outset attributes to create three-dimensional effects.