.sosikizu ul li ul li {
  margin-bottom: .25em;
  position: relative;
}


.sosikizu ul li ul li::before {
  content: "";
  position: absolute;
  top: -0.5em;
  left: -16px;
  width: 10px;
  height: calc(100% + .75em);
  border-left: 1px solid #3972b2;
}

.sosikizu ul li ul li::after {
  content: "";
  position: absolute;
  top: .75em;
  left: -16px;
  width: 10px;
  border-bottom: 1px solid #3972b2;