Font Weight

<https://www.tailwindcss.cn/docs/font-weight>

用法

Class	Properties
font-thin	font-weight: 100;
font-extralight	font-weight: 200;
font-light	font-weight: 300;
font-normal	font-weight: 400;
font-medium	font-weight: 500;
font-semibold	font-weight: 600;
font-bold	font-weight: 700;
font-extrabold	font-weight: 800;
font-black	font-weight: 900;