chore demo: fix flexbox demo
chore demo: fix flexbox demo

jefvel/lumX,lumapps/lumX,hinablue/lumX,hinablue/lumX,jefvel/lumX,hinablue/lumX,jefvel/lumX,lumapps/lumX,lumapps/lumX,hinablue/lumX,lumapps/lumX,jefvel/lumX