按距离

::v-deep .v-divider {
  max-height: 3px;
  height: 3px;
  margin-top: 15px;
  background-image: linear-gradient(to right, #C71A1A 40px, #FFF2EA 80px);
}

按比例

::v-deep .v-divider {
  max-height: 5px;
  height: 5px;
  background-image: linear-gradient(to right, #C71A1A 10% , #FFF2EA 20%);
  margin-top: 10%;
}