/* 여기에 스타일을 구현해 주세요 */

* {
  list-style: none;
}

body {
  height: 100vh;
  position: relative;
}

:root {
  --gap: 20px;
}

.wrapper {
  width: calc((64px * 4) + (var(--gap) * 3));
  margin: auto;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

.wrapper::after {
  content: '';
  display: block;
  clear: both;
}

ul {
  width: 100%;
  padding: 0;
  margin: 0;
}

.wrapper > ul::after {
  content: '';
  display: block;
  clear: both;
}

li {
  float: left;
  position: relative;
  width: 64px;
  height: 64px;
  margin-right: var(--gap);
  border-radius: 100%;
  margin-bottom: 20px;
}

li:nth-child(4n) {
  margin-right: 0px;
}

li:nth-last-child(-n + 4) {
  margin-bottom: 0px;
}

img {
  width: 100%;
  height: 100%;
  border-radius: 50%;
}

li::after {
  position: absolute;
  top: calc(100% - 16px);
  left: calc(100% - 16px);
  content: '';
  width: 16px;
  height: 16px;
  background-color: #dbdbdb;
  border-radius: 50%;
  border: 2px solid white;
  box-sizing: border-box;
}

.avatar.online::after {
  background-color: #4cfe88;
}