How is this effect achieved_html/css_WEB-ITnose

How can I make him feel concave? I used "inset" and "ridge" but it didn't work. . . . .

Reply to discussion (solution)

css3 should have rounded corners and inner shadow effects

css3 should have rounded corners and inner shadow effects

I have rounded corners, how can I get the shadow effect?

Protruding top, left bright color
Recessed bottom, left bright color

http://www.css3.info/preview/box-shadow/
Style K, then Add rounded corners yourself