background-color: #3C1D3D;
border-top: .5em solid #000;
border-bottom: .5em solid #000;
background-image: linear-gradient(135deg, transparent, transparent 14px,
rgba(0,0,0,.1) 14px, rgba(0,0,0,.1) 15px, transparent 15px, transparent);
background-size: 20px 20px;
background-attachment: fixed;
Não entendi a lógica desse linear-gradient , alguém ajuda?