You should combine all your CSS into one file to reduce the amount of requests made to your server.
A similar topic is sprite sheets
, the combination of multiple images into one large image to also reduce the amount of requests made to your server.
You'll find that loading 100x 5kb files is a lot slower than loading a single 500kb file.
When you're ready to upload your files to a live environment, you should also consider compressing your CSS and JavaScript files. There are a vast amount of online tools for this, eg:
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…