Viewport

<meta name="viewport" content=-"width=device-width,initial-scale=1">

Media query and breakpoint

@media screen and (max|min-width:400px){css}

FlexBox

display: flex;
flex-wrap: wrap;

Column Drop

Mostly Fluid

Layout Shifter

Off Canvas

Reference

• http://www.lukew.com/ff/entry.asp?1514
• https://www.udacity.com/course/progress#!/c-ud893