practice-time-landing-page/assets/styles/style.css

 html, body{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
 }
.header{
   display: flex;
   justify-content: center;
   background: black;
   padding: 28px 0;
}
.imagemPrincipal img{
   max-width: 100%;
}
@media only screen and (max-width: 414px){
       .bannerPrincipalDesktop{
         display: none;
       }
}
@media only screen and (min-width: 414px){
   .bannerPrincipalMobile{
     display: none;
   }
}