Be friendly, but not overly casual or familiar.

要友善，但不要过度随便或套近乎。

youdao

The blue is a bit bolder this time around, but it's not overwhelming, which is key to the casual mood.

蓝色在这里稍显凝重，但不会带来严重的压迫感，所以在这里成为了带来随意的情绪的关键。

youdao

My father had mentioned him regularly, not as a part of normal conversation but as a casual aside that could come up at any time without warning.

我父亲总是时不时地提到他，不是通常的谈话，而是随随便便，不知什么时候就冒出来一句。

youdao

The illness could be spread by sex and kissing but not by casual contact.

WSJ: West Hollywood officials warn of meningitis

It is near a monument set on the top of Coombe Hill but not so close that casual searching will find it.

BBC: How to play hide-and-seek by satellite

It sounds like a good book, and it will certainly sell well, but The Casual Vacancy is not the stuff of entertainment franchises.

FORBES: Muggle-Ware: Will The iPad Mini Be Apple's First Non-Magical Product?