Such a concept is completely wrong and improper. Teaching such content to a child is not only immoral but also may cause long-term harm to the child's mental and emotional well-being.
They often have a simple and classic look. The black and white tones give a timeless feel and can focus on the essentials of the subjects like food and water.
The main features of 'Under the Oak Tree' manhwa include detailed character designs, a compelling love story, and a rich fantasy world. The art style is very appealing and helps draw you into the story. Also, the character development is deep, making you really care about what happens to them.
It's possible that the style of the cartoon girl with sunglasses is cute and fun. Maybe she has colorful clothing or unique accessories that make her stand out while still looking charming behind those sunglasses.
Maybe it's part of a story or theme where the bear has had a wild adventure and ended up drunk in the recliner. It might be designed to catch people's attention and spark their imagination.