<div class="box"></div>

html {
  background-color: #111318;
}

.box {
  width: 400px;
  height: 100px;
  background: linear-gradient(#111318, #111318) 50% 50% / calc(100% - 5px)
      calc(100% - 5px) no-repeat,
    linear-gradient(150deg, #b3a97f 38%, #111318 40%, #111318 83%, #b3a97f 85%);
}