styles.css

body {
  background: #0f0f23;
  color: #cccccc;
  font-family: "Source Code Pro", monospace;
  font-size: 14pt;
}

/* menu */

div#day-selector {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

div#day-selector a {
  border-radius: 3px;
  color: #fff;
  text-decoration: none;
  padding: 10px;
  background: rgba(119, 119, 165, .05);
}

div#day-selector a:hover {
  background: rgba(119, 119, 165, .2);
  text-decoration: none;
}

div#day-selector a::before {
  content: '⭐';
  margin: 0 10px 0 0;
}

div#day-selector a[data-progress] {
  opacity: 1;
  filter: grayscale(1);
}

div#day-selector a:not([data-complete]):not([data-progress]) {
  opacity: 0.3;
  filter: grayscale(1);
  pointer-events: none;
  cursor: default;
}

/* in puzzle */

div.total-element {
  background: rgba(0, 0, 0, .7);
  color: #fff;
  border: 1px solid #fff;
  border-radius: 3px;
  text-align: center;
  font-weight: bold;
  margin: 25px 0 15px;
  padding: 10px;
  top: 10px;
  left: 15px;
  position: sticky;
}