They help the menu or window stand out from the background by reinforcing its dimensions. They also block out the noise of the content beneath the window by darkening the area around it with a shadow.

这些阴影通过增加菜单或者窗口的维度来使它们变得醒目，同时也能来把这块区域变暗以阻止下方内容的干扰。

youdao

O Stand in a shady area then close your eyes.

站在荫凉的区域内，然后闭上眼睛。

youdao

Above, people stand next to traffic lights on the Bund area on Aug. 10.

这是8月10日站在外滩地区靠近交通灯的过街天桥上的市民。

youdao

But the military says it is in no hurry to enter the area from where the rebels are expected to make their last stand.

VOA: standard.2009.04.06

Like, it's extremely popular now to be totally against the war, so I think the majority of them have taken a firm stand in that area.

NPR: Milford Locals Talk Parade, Politics on Labor Day

Retailers are installing 3D sensors directly over the area where customers stand in front of a retail store section.

FORBES: How Walmart and Heineken Will Use Shopperception to Put Your In-store Experience in Context

"While the harbor was closed, any vessel in the area was asked to stand by, " Zubricki said.

CNN: Bomb threats close Boston Harbor