.center{height:100px;width:100px}.login-principal{border-radius:20px}.leger{opacity:.2}.moyen{opacity:.5}.lourd{opacity:.9}.background{padding:20px;background:linear-gradient(-45deg,#ee7752,#e73c7e,#23a6d5,#23d5ab);background-size:400% 400%;-webkit-animation:gradientBG 15s ease infinite;animation:gradientBG 15s ease infinite}.box{background:hsla(0,0%,100%,.2)}.box2{font-size:18px;font-weight:100;color:#000}