Flexbox is a CSS3 layout mode used to make layouts for web pages and applications. It gives user to complete control over boxes size, direction, order, alignment and make complex layouts to display easily on mobile phones.
CSS stands for casecading style sheet, it is used to style web page and make it interactive. Developers use CSS to control text color, background color, margin, padding and border of boxes or other HTML elements. CSS uses different types of layouts to arrange elements position like display block, inline and table.
Flexbox is the CSS3 layout for mobile friendly applications, flexbox make your application to look same on different devices, flexbox is used to control the layout of application, order, alignment and direction of elements. All modern browsers support flexbox.