web app要求内容的趣味性，设计师通常会使用一些与设计风格相匹配的字形（而这些字体通常不是google web font），如果目标用户非移动用户，这个可以用图片来解决（css sprite），但如果需要一个responsive的web app，这是个非常糟糕的选择。css sprite对其背景定位和大小尺寸需要相当准确，无法适应对尺寸要求极度宽松的响应式，并且多而大的图片对加载速度影响很大。因此，建议使用google web font（上面有很多漂亮的字形，限英文）或系统默认字体。当然也有嵌入字体只说，但如果是中文，可要考虑字库大小哦~
“At first, responsive design was applied to existing desktop-centric websites to allow the layout to adapt to smaller screen sizes. But more recently it has been combined with another innovative approach called mobile first.
Rather then starting with the big, bloated desktop site and then scaling down for smaller devices, it makes more sense to start with the constraints of the small screen and then scale up for larger viewports. Using this approach, your layout grid, your large images and your media queries are applied on top of the pre-existing small-screen design. It’s taking progressive enhancement to the next level.
One of the great advantages of the mobile-first approach is that it forces you to really focus on the core content of your page. It might be more accurate to think of this as a content-first approach. You don’t have the luxury of sidebars or multiple columns to fill up with content that’s just nice to have rather than essential.”