index.css

* {
  font-family: "Charm", cursive;
  font-family: "Instrument Serif", serif;
  font-family: "Sono", sans-serif;
}

body {
  background-color: black;
}

.kanban {
  display: flex;
  padding: 80px;
  width: 750px;
  background: mediumslateblue;
  border-radius: 5px;
  margin: 0 auto;
  text-align: center;
}

.kanban * {
  font-family: sans-serif;
}

.kanban__column {
  flex: 1;
}

.kanban__column:not(:last-child) {
  margin-right: 30px;
}

.kanban__column-title {
  margin-bottom: 20px;
  font-size: 30px;
  color: white;
  user-select: none;
}

.kanban__item-input {
  padding: 10px 15px;
  box-sizing: border-box;
  background: white;
  border-radius: 5px;
  cursor: pointer;
}

.kanban__dropzone {
  height: 10px;
  transition: background 0.15s, height 0.15s;
}

.kanban__dropzone--active {
  height: 20px;
  background: rgba(0, 0, 0, 0.25);
}

.kanban__add-item {
  width: 100%;
  padding: 10px 0;
  font-size: 16px;
  color: white;
  background: rgba(0, 0, 0, 0.1);
  border: none;
  border-radius: 5px;
  cursor: pointer;
}