<div class="card" data-attr="without :not()">
  <div class="card-heading">
    <div class="lines"></div>
  </div>
  <div class="card-body">
    <ul>
      <li>
        <div class="avatar"></div>
        <div class="lines"></div>
      </li>
      <li>
        <div class="avatar"></div>
        <div class="lines"></div>
      </li>
    </ul>
  </div>
</div>

<div class="card" data-attr="with :not()">
  <div class="card-heading">
    <div class="lines"></div>
  </div>
  <div class="card-body">
    <ul>
      <li>
        <div class="avatar"></div>
        <div class="lines"></div>
      </li>
      <li>
        <div class="avatar"></div>
        <div class="lines"></div>
      </li>
    </ul>
  </div>
</div>

body {
  width: 100vw;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding: 2vw;
  background: #eaeaea;
}
.card {
  border-radius: 8px;
  padding: 20px;
  background: #eaeaea;
  border: 1px solid #aeaeae;
  margin: 10px;
  position: relative;
  
  &::before {
    content: attr(data-attr);
    position: absolute;
    padding: 10px;
    background: linear-gradient(to right, #f36, #f63);
    color: #fff;
    border-radius: 5px;
    top: -25px;
  }
}

ul {
  list-style-type: none;
  width: 500px;
  margin: 0;
  padding: 0;
}
li {
  background: white;
  border-radius: 8px;
  overflow: hidden;
  padding: 20px;
  position: relative;
  display: flex;
}
.avatar {
  background: #eaeaea;
  border-radius: 4px;
  width: 80px;
  height: 80px;
}
.lines {
  height: 80px;
  margin-left: 20px;
  flex: 1;
}
.lines:before, 
.lines:after {
  background: #eaeaea;
  content: ' ';
  display: block;
  margin-bottom: 10px;
  width: 100%;
  height: 10px;
}

.card-heading .lines{
  height: auto;
  margin-left: 0;
  
  &:before,
  &:after {
    background: #fff;
    margin-left: 0;
  }
}

.card[data-attr ~= "without"] li{
  margin-bottom: 20px;
}

.card[data-attr~="with"] li:not(:last-child){
  margin-bottom: 20px;
}