Web design trends or approaches often change over time (sometimes very quickly). Here are a few current approaches.
Skeuomorphism
The web site or application is designed using elements that look like the real-world version. Example: the recycle bin icon looks like a trash can.
Flat Design
Flat design uses rectangles or squares to represent controls; there is no depth to these.
Material design (Google concept)
Basically this is an implementation of flat design that is somewhat influenced by skeumorphism.
Neomorphism
Neomorphism is a very simplified version of skeuomorphism that is heavily influenced by flat design. While a hyperlink may still be represented by a square or rectangle, there will be a little depth created using shadows, often multiple box-shadows. Note the use of transparency in the following example.
CSS .box {box-shadow: 12px 12px 16px 0 rgba(0, 0, 0, 0.25), -8px -8px 12px 0 rgba(255, 255, 240, 0.3)};
Glassmorphism
Glassmorphism simply refers to using a "frosted glass" or blurred region as a button or other element.
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