:root {
  --cell-size: 4vw;
  --highlight: #373839;
  --background-color: rgb(13, 11, 19);
}

* {
  box-sizing: border-box;
}

body {
  background-color: var(--background-color, rgb(13, 11, 19));
  margin: 0;
  height: 100vh;
  color: var(--highlight);
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: clamp(1em, 1vw, 50px);
}

.group {
  display: flex;
  justify-content: space-evenly;
  align-items: center;
  width: 50%;
}

.container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  min-width: 70vw;
}

.flex-col {
  display: flex;
  flex-direction: column;
  justify-content: space-evenly;
  align-items: center;
  --border: 5;
  min-height: 80vh;
}

.cells {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}

.cells .cell {
  height: var(--cell-size);
  width: var(--cell-size);
  min-height: 35px;
  color: var(--background-color, rgb(13, 11, 19));
  display: flex;
  font-size: 20px;
  justify-content: center;
  align-items: center;
  min-width: 35px;
  border: calc(var(--border) * 1px) solid var(--highlight);
  margin: calc(var(--border) / 2 * -1px) 0;
}

.hour-group .cell.show {
  background-color: hsl(0, 50%, 50%);
}
.minute-group .cell.show {
  background-color: hsl(100, 50%, 60%);
}
.second-group .cell.show {
  background-color: hsl(200, 50%, 60%);
}