Layout: Using shapes and color rather than borders and lines to separate page sections makes it more asymmetric casual and youthful. It makes information sleek while keeping the fun element.

 Style: Playful elements, youngish style and a lots of colors look dynamic  and delightful

Shapes:  The radius roundness of button gives a playful feeling. Geometric shapes looks dynamic The flat design illustration is modern and trendy.

Fonts: Use Avenir Next, a geometric sans-serif typeface. The word avenir is French for "future". It has a modern and cute looking.

language: The use of causal English sounds natural, casual and informal.

Color: The luminosity and saturation pop out. The application of vivid color shows great contrast and  grab young people’s attention.