body {
  --grid-color-white: #e6e7e8;
  --grid-color-green: #78b159;
  --grid-color-black: #31373d;

  --palette-celadon-green: #21897eff;
  --palette-oxford-blue: #001427ff;
  --palette-french-sky-blue: #65afffff;
  --palette-fuzzy-wuzzy: #d16666ff;
  --palette-tea-green: #c5edacff;

  --marker-color: var(--palette-french-sky-blue);
  --marker-size: 1rem;

  --stripe-width: 2rem;
  --stripe-angle: -45deg;
  --stripe-color-choose-player: var(--palette-oxford-blue);
  --stripe-color-spoiler: var(--palette-fuzzy-wuzzy);

  --nav-color-active: var(--palette-french-sky-blue);
  --nav-color-hover: var(--palette-tea-green);

  min-width: 20rem;
  max-width: 40rem;
  min-height: 100vh;
  margin: 0 auto;
  padding: 0.5rem 0.5rem 0;
  box-sizing: border-box;
  display: flex;
  flex-direction: column;
  font-family: monospace;
}
nav {
  display: flex;
  flex-direction: row;
  align-items: stretch;
  gap: 0.5rem;
  font-size: 2rem;
}
nav > span,
nav > a {
  padding: 1rem 0;
}
nav > span {
  font-weight: bold;
}
nav > a {
  border-radius: 0.25rem;
  flex: 1;
  text-align: center;
}
nav > a:hover {
  background: var(--nav-color-hover);
}
nav > a,
nav > a:visited {
  color: inherit;
}
nav > a.active {
  background: var(--nav-color-active);
  position: relative;
}
nav > a.active:before {
  content: "●";
  font-size: 1rem;
  position: absolute;
  top: 0;
  right: 0.5rem;
}
nav > a.active:hover:before {
  content: "×";
}

/*
    Add side margins to all top-level elements except the grid container.
    The value of the margin is set so that the elements are vertically aligned with the grids
*/
nav,
menu[role="toolbar"],
footer {
  margin: 0 calc(5px + 1rem); /* grid border + grid padding */
}

.grid-container {
  border: 5px solid transparent;
  border-image: linear-gradient(
      to bottom left,
      var(--marker-color),
      var(--marker-color) var(--marker-size),
      transparent calc(2 * var(--marker-size))
    )
    1;
  padding: 1rem;
  margin: 1rem 0;
  box-sizing: border-box;
  aspect-ratio: 1 / 1;
  transition: transform 1s ease-out;

  position: relative;
}
.grid-container > .grid,
.grid-container.spoiler > .grid:target {
  display: none;
}
.grid-container > .grid:target {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 1rem;
}

.grid-container.empty,
.grid-container.spoiler {
  border-image: none;
  position: relative;
  padding: calc(5px + 1rem);
  border-width: 0;
  background-clip: content-box;
}

.grid-container.empty:before,
.grid-container.spoiler:before {
  font-size: 3rem;
  background: rgba(255, 255, 255, 0.8);
  padding: 1rem;
  border-radius: 0.5rem;
  position: absolute;
  bottom: 50%;
  left: 1rem;
  width: calc(100% - 2rem);
  text-align: center;
  box-sizing: border-box;
}
.grid-container.spoiler {
  background-image: repeating-linear-gradient(
    var(--stripe-angle),
    var(--stripe-color-spoiler),
    var(--stripe-color-spoiler) var(--stripe-width),
    white var(--stripe-width),
    white calc(2 * var(--stripe-width))
  );
}
.grid-container.spoiler:before {
  content: "Click to reveal";
}
@media (any-pointer: coarse) {
  .grid-container.spoiler:before {
    content: "Tap to reveal";
  }
}

.grid-container.empty {
  background-image: repeating-linear-gradient(
    var(--stripe-angle),
    var(--stripe-color-choose-player),
    var(--stripe-color-choose-player) var(--stripe-width),
    white var(--stripe-width),
    white calc(2 * var(--stripe-width))
  );
}
.grid-container.empty:before {
  content: "Choose a player";
}

.grid-container.easteregg > .grid > .card {
  position: relative;
}
.grid-container.easteregg > .grid > .card:before {
  position: absolute;
  top: calc(50% - 2.25rem);
  left: calc(50% - 2rem);
  font-size: 3rem;
  padding: 0.5rem;
  background: #ffffffaa;
  box-sizing: border-box;
  border-radius: 0.5rem;
}

.grid-container.easteregg > .grid > .card.white:before {
  content: "⛄"; /* snowman */
}

.grid-container.easteregg > .grid > .card.green:before {
  content: "🐍"; /* snake */
}

.grid-container.easteregg > .grid > .card.black:before {
  content: "🐈‍⬛"; /* black cat */
}

.grid > .card {
  border-radius: 0.5rem;
  aspect-ratio: 1 / 1;
}
.grid > .white {
  background: var(--grid-color-white);
}
.grid > .green {
  background: var(--grid-color-green);
}
.grid > .black {
  background: var(--grid-color-black);
}

menu[role="toolbar"] {
  list-style: none;
  padding: 0;
  display: flex;
  flex-direction: row;
  font-size: 3rem;
  gap: 1rem;
}
menu[role="toolbar"] > li.grow {
  flex: 1;
}
menu[role="toolbar"] > li > button {
  height: 100%;
  width: 100%;
  padding: 1rem 0.5rem;
  font-size: inherit;
}
footer {
  font-style: italic;
  text-align: right;
  background: var(--palette-celadon-green);
}
.spacer {
  border: 0;
  flex: 1;
}