Self-tutoring about web effects: the tutor mentions mirror text. Hello, world! I’ve been told being able to write so you can read it in a mirror is a rare skill. Well, CSS has you covered, with transform: scale(-1,1) Source:

Self-tutoring about web design: the tutor mentions the term void element. void element: An element that contains no displayed content. Rather, it contains information, in the form of attributes. The link and meta tags are examples. Source:

Self-tutoring about color multiplication: the tutor looks at a method. A way to define multiplication of two colors rgb(Ar,Ag,Ab)and rgb(Br,Bg,Bb) is rgb(Ar*Br/255,Ag*Bg/255,Ab*Bb/255). For example rgb(100,100,100)*rgb(100,0,100)=rgb(39,0,39), seen as color1*color2=color3

Self-tutoring about web design: the tutor mentions some formats for stating border-color. Hello! border-color:red green; Hello! border-color:red green blue Hello! border-color:red green blue yellow Source: