.header { background-image: url('../img/background.jpg'); background-position: center; background-size: cover; width: 100vw; height: 100vh; line-height: 100vh; }
.backimg { background-color: rgba(255,255,255,0.3); height: 100vh; line-height: 100vh; display: none; }
.header img { margin-left: auto; margin-right: auto; display: block; max-width: 55vw; position: relative; top: 50%; transform: translateY(-50%); }