.greek-key-border{position:relative;padding:20px;border:10px solid #000;background-image:linear-gradient(45deg,transparent 25%,rgba(0,0,0,0.15) 25%,rgba(0,0,0,0.15) 50%,transparent 50%,transparent 75%,rgba(0,0,0,0.15) 75%,rgba(0,0,0,0.15) 100%);background-size:20px 20px}.greek-key-border::before{content:'';position:absolute;top:-15px;left:-15px;right:-15px;bottom:-15px;border:10px solid #000;background-image:linear-gradient(45deg,transparent 25%,rgba(0,0,0,0.15) 25%,rgba(0,0,0,0.15) 50%,transparent 50%,transparent 75%,rgba(0,0,0,0.15) 75%,rgba(0,0,0,0.15) 100%);background-size:20px 20px;z-index:-1}