* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  background: url('./bg.png') no-repeat center top/cover fixed;
}
.docker-container {
  position: fixed;
  bottom: 10px;
  display: flex;
  justify-content: center;
  width: 100%;
}

.docker {
  box-sizing: content-box;
  height: 30px;
  display: flex;
  justify-content: center;
  align-items: end;
  padding: 5px 10px;
  background: rgba(255, 255, 255, 0.3);
  backdrop-filter: blur(15px);
  border: 1px solid #aaa;
  border-radius: 5px;
  position: relative;
}

.menu {
  display: flex;
  align-items: end;
}
.menu-item {
  border-radius: 5px;
  width: calc(var(--i, 1) * 30px);
  height: calc(var(--i, 1) * 30px);
  margin-bottom: calc(var(--i, 1) * 15px - 15px);
  background: #b4433d;
  border: 1px solid #ccc;
}
.menu-item:nth-child(3n) {
  background: #1a862a;
}
.menu-item:nth-child(3n + 2) {
  background: #e8ad2d;
}
.gap {
  height: 100%;
  width: calc(var(--i, 1) * 10px);
  height: 30px;
}

@property --i {
  syntax: '<number>';
  initial-value: 1;
  inherits: false;
}