flex-grow : 1; // this means that the div will grow in same proportion as the window-size
flex-shrink : 1; // this means that the div will shrink in same proportion as the window-size
flex-basis : 0; // this means that the div does not have a starting value as such and will take up screen as per the screen size available for.e.g:- if 3 divs are in the wrapper then each div will take 33%.
flex：1表示以上内容，翻译过来就是
flex-grow : 1; // 这意味着div将以与窗口大小相同的比例增长
flex-shrink : 1; // 这意味着div将以与窗口大小相同的比例缩小
flex-basis : 0; // 这意味着div没有这样的起始值，并且将根据可用的屏幕大小占用屏幕。例如： - 如果包装器中有3个div，则每个div将占用33％。