hi dear
I had create a CSS style for my container,and this flex container also bind this style,however this style not works in deed, could you please provide best solution
click on the save button
If the save button doesn't fix it, copy/paste all of your styles from the styles folder into a text editor and look for invalid CSS. When you select copy styles from the designer it copies the CSS code to the paste buffer.
I had some styles that worked in an older Ignition but had bonus semicolons in a newer Ignition. I systematically updated the styles to make them work properly in the newer one.
after save， it still not works 
I try to add these files into VS code, and there are nothing different from the right css, and when i Capitalize the first letter of CSS name finally it works, and copy it into a folder it also not work, a liitle funny, how to recover this issue ?
You can view the css for these in the dev tools which collates them all together for you. Just find some of your style class styles in the Dom view styles and click on the link next to them on the right eg "styles.css" and it will jump over to the stylesheet. Much simpler than opening all of the json-encoded css files manually