width: 500px;
height: 500px;
background:
linear-gradient(22deg, rgba(165,171,173,1) 29%, rgba(75,78,79,0) 30%) 250px 111px / 100px 100px no-repeat no-repeat, /* Top */
linear-gradient(-22deg, rgba(165,171,173,1) 29%, rgba(75,78,79,0) 30%) 150px 111px / 100px 100px no-repeat no-repeat, /* Top */
linear-gradient(202deg, rgba(165,171,173,1) 29%, rgba(75,78,79,0) 30%) 150px 210px / 100px 100px no-repeat no-repeat, /* Top */
linear-gradient(158deg, rgba(165,171,173,1) 29%, rgba(75,78,79,0) 30%) 250px 210px / 100px 100px no-repeat no-repeat, /* Top */
linear-gradient(202deg, rgba(75,78,79,0) 29%, rgba(128,133,137,1) 29%, rgba(128,133,137,1) 69%, rgba(75,78,79,0) 69%) 150px 161px / 100px 270px no-repeat no-repeat, /* Left */
linear-gradient(158deg, rgba(75,78,79,0) 29%, rgba(87,92,94,1) 29%, rgba(87,92,94,1) 69%, rgba(75,78,79,0) 69%) 250px 161px / 100px 270px no-repeat no-repeat, /* Right */
linear-gradient(158deg, rgba(75,78,79,0) 29%, rgba(234,241,244,1) 29%, rgba(234,241,244,1) 57%, rgba(75,78,79,0) 69%) 250px 239px / 100px 260px no-repeat no-repeat, /* Glow right */
linear-gradient(202deg, rgba(75,78,79,0) 29%, rgba(234,241,244,1) 29%, rgba(234,241,244,1) 57%, rgba(75,78,79,0) 69%) 150px 238px / 100px 260px no-repeat no-repeat, /* Glow left */
linear-gradient(rgba(183,209,217,1), rgba(183,209,217,1)) 0px 0px / 500px 500px no-repeat no-repeat; /* Background */