320 and up is an extension to the HTML5 boilerplate that starts with a style sheet for small screen devices and then uses progressive enhancement by using media queries to load enhanced layout and assets as they are required.
320 and up can be used standalone or by using it with the HTML5 boilerplate, in which case some files need to be replaced within the boilerplate package.
- five media query increments: 480, 600, 768, 992 & 1382 pixels
- a vertical grid based on Less Framework 4
- either a single style sheet with multiple media queries or multiple linked style sheets
- combined HTML5 boilerplate and mobile boilerplate components
- typography preset styles
- imgsizer.js to improve IE’s rendering of resizeable images
- selectivizr.js – bootstrap CSS3 selector support
- jquery-extra-selectors.js to boost Selectivizr