Is HTML5 and CSS3 supported by HTA? If I am planning to use my application only with Windows operating system: It is a simple application that does some basic file handling, is HTA a viable option?
Will there be any serious performance issues if I use a simple flat file (text file) to store data of my HTA?
HTAs not only support everything a webpage does—namely HTML, Cascading Style Sheets (CSS), scripting languages, and behaviors—but also HTA–specific functionality. This added functionality provides control over user interface design and access to the client system.
http://msdn.microsoft.com/en-us/library/ms536496(v=vs.85).aspx
To summarize, you have to include such kind of meta line in your HTA to make it support CSS3:
<meta http-equiv="x-ua-compatible" content="ie=9">
来源：https://stackoverflow.com/questions/8219361/css3-support-for-hta