/*
ORDRE z-index

xxxxxxxxxxxxxxxxxxxxxxxx z-index: 1; xxxxxxxxxxxxxxxxxxxxxxxx
Dans 3-settingsNavigByPage.css
(obligé de lui donné un z-index pour pouvoir faire passer la modal(.slide__modal) au-dessus de la navbar (.header-main))
.main__content 


Dans 7-gallery.css
.slide__square:before 
.slide__square-summary:before
.slide__modal

xxxxxxxxxxxxxxxxxxxxxxxx z-index: 2; xxxxxxxxxxxxxxxxxxxxxxxx
Dans 7-gallery.css
.square-sum-txt
.opacity-effect

xxxxxxxxxxxxxxx z-index: 3; xxxxxxxxxxxxxx
Dans 3-settingsNavigByPage.css
.header-main
Dans 100-mediaqueries.css
.nav-main__ul

xxxxxxxxxxxxxxx z-index: 4; xxxxxxxxxxxxxx
xxxxxxxxxxxxxxx z-index: 5; xxxxxxxxxxxxxx
xxxxxxxxxxxxxxx z-index: 6; xxxxxxxxxxxxxx
xxxxxxxxxxxxxxx z-index: 7; xxxxxxxxxxxxxx
xxxxxxxxxxxxxxx z-index: 8; xxxxxxxxxxxxxx
xxxxxxxxxxxxxxx z-index: 9; xxxxxxxxxxxxxx
xxxxxxxxxxxxxxx z-index: 10; xxxxxxxxxxxxxxx

*/