hello, world!

This is my window modal test.

1. display: relative;

   Click this button for show my modal.

2. display: absolute;

   Click this button for show my modal.

3. display: fixed;

   Click this button for show my modal.

This is my z-index test.

1. z-index: 3;

   Click this button for show z-index 3.

2. z-index: 2;

   Click this button for show z-index 2.

3. z-index: 1;

   Click this button for show z-index 1.