:root {
  font-family: "Helvetica Neue", sans-serif;
  font-synthesis: none;
  color: #2b302c;
  background: #f7f6f2;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  --text-small: 13px;
  --text-label: 14px;
  --text-title: 20px;
  --board-light: #ecebdc;
  --board-dark: #7f9680;
  --coordinate-space: 24px;
  --controls-space: 196px;
  --ease-out: cubic-bezier(0.23, 1, 0.32, 1);
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

body {
  min-block-size: 100svh;
  margin: 0;
  padding: 24px;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  place-items: center;
}

button {
  font: inherit;
  color: inherit;
  -webkit-tap-highlight-color: transparent;
}

.chess {
  inline-size: min(100%, 704px, max(320px, calc(100svh - var(--controls-space))));
  min-inline-size: 0;
}

.heading {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  margin-inline-start: var(--coordinate-space);
  margin-block-end: 20px;
}

h1,
h2,
p {
  margin: 0;
}

h1 {
  font-size: var(--text-title);
  font-weight: 500;
  line-height: 1.1;
  letter-spacing: -0.6px;
}

.position {
  color: #62695f;
  font-size: var(--text-small);
  line-height: 1.5;
  white-space: nowrap;
}

.board-layout {
  display: grid;
  grid-template-columns: var(--coordinate-space) minmax(0, 1fr);
  grid-template-rows: auto var(--coordinate-space);
}

.board {
  display: grid;
  grid-template-rows: repeat(8, minmax(0, 1fr));
  aspect-ratio: 1;
  overflow: hidden;
  border-radius: 3px;
  touch-action: none;
  user-select: none;
}

.rank {
  display: grid;
  grid-template-columns: repeat(8, minmax(0, 1fr));
  min-block-size: 0;
}

.cell {
  min-inline-size: 0;
  min-block-size: 0;
}

.square {
  --square-color: var(--board-light);
  position: relative;
  display: grid;
  place-items: center;
  inline-size: 100%;
  block-size: 100%;
  min-inline-size: 0;
  min-block-size: 0;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: var(--square-color);
  cursor: pointer;
  transition: background-color 140ms ease;
}

.square.dark {
  --square-color: var(--board-dark);
}

.square.last-move {
  background: color-mix(in srgb, var(--square-color), #dac970 36%);
}

.square.selected {
  background: color-mix(in srgb, var(--square-color), #d4bd5c 68%);
}

.square.in-check {
  background: color-mix(in srgb, var(--square-color), #d07569 72%);
}

.square[data-friendly="true"] {
  cursor: grab;
}

.square:disabled {
  cursor: default;
}

.square::before,
.square::after {
  content: "";
  position: absolute;
  border-radius: 50%;
  opacity: 0;
  scale: 0.94;
  pointer-events: none;
  transition: opacity 120ms ease, scale 140ms var(--ease-out);
}

.square::before {
  inline-size: 24%;
  block-size: 24%;
  background: rgb(33 48 35 / 30%);
}

.square::after {
  inline-size: 89%;
  block-size: 89%;
  border: 5px solid rgb(33 48 35 / 38%);
  background: transparent;
}

.square.legal-target:not(.capture-target)::before,
.square.capture-target::after {
  opacity: 1;
  scale: 1;
}

.square.drop-target {
  outline: 3px solid #52634b;
  outline-offset: -3px;
}

.square:focus-visible {
  outline: 3px solid #273b28;
  outline-offset: -3px;
  z-index: 1;
}

.piece {
  display: block;
  inline-size: 100%;
  block-size: 100%;
  object-fit: contain;
  pointer-events: none;
  user-select: none;
  -webkit-user-drag: none;
}

.drag-origin .piece,
.piece-moving .piece {
  visibility: hidden;
}

.motion-piece,
.capture-ghost {
  position: fixed;
  display: block;
  margin: 0;
  object-fit: contain;
  pointer-events: none;
  user-select: none;
  -webkit-user-drag: none;
}

.motion-piece {
  z-index: 4;
}

.capture-ghost {
  z-index: 3;
}

.drag-piece {
  position: fixed;
  inset-block-start: 0;
  inset-inline-start: 0;
  z-index: 10;
  object-fit: contain;
  pointer-events: none;
  user-select: none;
}

.dragging,
.dragging .square {
  cursor: grabbing;
}

.coordinates {
  display: grid;
  align-items: center;
  color: #62695f;
  font-size: var(--text-small);
  font-variant-numeric: tabular-nums;
  line-height: 1;
  user-select: none;
}

.ranks {
  grid-template-rows: repeat(8, 1fr);
}

.files {
  grid-column: 2;
  grid-template-columns: repeat(8, 1fr);
  text-align: center;
  align-items: end;
}

.footer {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 12px;
  margin-inline-start: var(--coordinate-space);
  margin-block-start: 16px;
  font-size: var(--text-label);
  line-height: 1.5;
}

.turn {
  display: flex;
  align-items: center;
  gap: 8px;
  min-block-size: 24px;
}

.turn-marker {
  flex: none;
  inline-size: 10px;
  block-size: 10px;
  border: 1px solid #697268;
  border-radius: 50%;
  background: #fff;
}

.turn-marker.black {
  border-color: #393d39;
  background: #51514f;
}

.toolbar {
  display: flex;
  align-items: center;
  justify-content: end;
  gap: 4px;
}

.tool {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-block-size: 44px;
  min-inline-size: 44px;
  padding: 0 12px;
  border: 0;
  border-radius: 6px;
  background: transparent;
  font-size: var(--text-small);
  line-height: 1;
  white-space: nowrap;
  cursor: pointer;
  user-select: none;
  transition: background-color 140ms ease, scale 140ms var(--ease-out);
}

.tool:active:not(:disabled),
.promotion-choice:active {
  scale: 0.96;
  transition-duration: 110ms;
}

.tool:focus-visible,
.promotion-choice:focus-visible {
  outline: 2px solid #52634b;
  outline-offset: 2px;
}

.tool:disabled {
  color: #9a9e96;
  cursor: default;
}

.new-game {
  background: #e6e9e1;
}

.moves {
  display: flex;
  align-items: center;
  gap: 18px;
  min-inline-size: 0;
  block-size: 36px;
  margin-block: 8px 0;
  margin-inline: var(--coordinate-space) 0;
  padding: 0;
  overflow-x: auto;
  overflow-y: hidden;
  list-style: none;
  font-size: var(--text-small);
  line-height: 1.5;
  font-variant-numeric: tabular-nums;
  scrollbar-width: thin;
  scrollbar-color: #c1c7bb transparent;
}

.moves:empty {
  visibility: hidden;
}

.move-pair {
  display: flex;
  align-items: baseline;
  flex: none;
  gap: 9px;
  white-space: nowrap;
}

.move-number {
  color: #74796f;
}

.latest-move {
  font-weight: 600;
}

.notice {
  margin-block-start: 12px;
  margin-inline-start: var(--coordinate-space);
  font-size: var(--text-small);
  line-height: 1.5;
  color: #765441;
  text-wrap: pretty;
}

.dialog {
  inline-size: min(400px, calc(100% - 32px));
  max-block-size: calc(100svh - 32px);
  padding: 24px;
  border: 1px solid #d7dcd1;
  border-radius: 12px;
  background: #f7f6f2;
  color: #2b302c;
  box-shadow: 0 8px 28px rgb(0 0 0 / 12%);
}

.dialog::backdrop {
  background: rgb(20 28 21 / 34%);
}

.dialog:not([open]),
.dialog:not([open])::backdrop {
  pointer-events: none;
}

@supports (transition-behavior: allow-discrete) and (overlay: auto) {
  .dialog {
    opacity: 0;
    scale: 0.98;
    transform-origin: center;
    transition:
      opacity 120ms var(--ease-out),
      scale 120ms var(--ease-out),
      display 120ms allow-discrete,
      overlay 120ms allow-discrete;
  }

  .dialog[open] {
    opacity: 1;
    scale: 1;
    transition-duration: 190ms;
  }

  .dialog::backdrop {
    opacity: 0;
    transition:
      opacity 120ms ease,
      display 120ms allow-discrete,
      overlay 120ms allow-discrete;
  }

  .dialog[open]::backdrop {
    opacity: 1;
    transition-duration: 190ms;
  }

  @starting-style {
    .dialog[open] {
      opacity: 0;
      scale: 0.98;
    }

    .dialog[open]::backdrop {
      opacity: 0;
    }
  }
}

.dialog h2 {
  font-size: 18px;
  font-weight: 500;
  line-height: 1.25;
  letter-spacing: -0.3px;
  text-wrap: balance;
}

.dialog p {
  margin-block-start: 12px;
  font-size: var(--text-label);
  line-height: 1.5;
  color: #62695f;
  text-wrap: pretty;
}

.dialog-actions {
  display: flex;
  justify-content: end;
  gap: 8px;
  margin-block-start: 24px;
}

.promotion-choices {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 8px;
  margin-block-start: 20px;
}

.promotion-choice {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  min-inline-size: 0;
  padding: 8px 0;
  border: 0;
  border-radius: 6px;
  background: #e6e9e1;
  font-size: var(--text-small);
  line-height: 1.5;
  cursor: pointer;
  transition: background-color 140ms ease, scale 140ms var(--ease-out);
}

.promotion-choice img {
  inline-size: 100%;
  block-size: auto;
  pointer-events: none;
}

.game-page {
  --controls-space: 282px;
}

.game-page.variant-game {
  --controls-space: 402px;
}

.game-settings {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px 12px;
  margin-inline-start: var(--coordinate-space);
  margin-block-end: 14px;
}

.game-setting {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-inline-size: 0;
  color: #62695f;
  font-size: var(--text-small);
}

.game-setting select {
  min-block-size: 44px;
  min-inline-size: 0;
  max-inline-size: 100%;
  padding-inline: 8px;
  border: 0;
  border-radius: 6px;
  background: #e6e9e1;
  color: #2b302c;
  font-family: inherit;
  font-size: 16px;
  cursor: pointer;
  transition: background-color 140ms ease;
}

.game-setting select:focus-visible {
  outline: 2px solid #52634b;
  outline-offset: 2px;
}

.game-setting select:disabled {
  cursor: default;
  opacity: 0.6;
}

.back-link {
  display: inline-flex;
  align-items: center;
  min-block-size: 44px;
  padding-inline: 6px;
  color: #62695f;
  font-size: var(--text-small);
  line-height: 1.5;
  text-decoration-thickness: from-font;
  text-underline-offset: 3px;
}

.back-link:focus-visible {
  outline: 2px solid #52634b;
  outline-offset: 3px;
}

.variant-info {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr);
  align-items: center;
  gap: 12px;
  margin-inline-start: var(--coordinate-space);
  margin-block-end: 18px;
  font-size: var(--text-label);
  line-height: 1.45;
}

.variant-info img {
  inline-size: 64px;
  block-size: 64px;
  object-fit: contain;
}

.variant-info .replacement {
  margin-block-start: 4px;
  color: #62695f;
  font-size: var(--text-small);
}

::selection {
  color: #fff;
  background: #526952;
}

@media (hover: hover) and (pointer: fine) {
  .tool:hover:not(:disabled) {
    background: #e8e9e2;
  }

  .promotion-choice:hover,
  .game-setting select:hover:not(:disabled) {
    background: #dce2d5;
  }
}

@media (max-width: 600px) {
  :root {
    --controls-space: 250px;
  }

  .game-page:not(.variant-game) {
    --controls-space: 330px;
  }

  .footer {
    grid-template-columns: minmax(0, 1fr);
    gap: 8px;
  }
}

@media (max-width: 480px) {
  :root {
    --coordinate-space: 20px;
  }

  body {
    padding: 24px 8px;
  }

  .heading {
    margin-block-end: 18px;
  }

  .dialog {
    padding: 20px;
  }
}

@media (max-height: 500px) {
  .chess {
    inline-size: min(100%, 384px);
  }
}

.keyboard-input .square,
.keyboard-input .square::before,
.keyboard-input .square::after,
.keyboard-input .tool,
.keyboard-input .promotion-choice,
.keyboard-input .game-setting select,
.keyboard-input .dialog,
.keyboard-input .dialog::backdrop {
  transition: none !important;
}

.keyboard-input .tool:active:not(:disabled),
.keyboard-input .promotion-choice:active {
  scale: 1;
}

@media (prefers-reduced-motion: reduce) {
  .square,
  .square::before,
  .square::after,
  .tool,
  .promotion-choice,
  .game-setting select,
  .dialog,
  .dialog::backdrop {
    transition: none !important;
  }

  .tool:active:not(:disabled),
  .promotion-choice:active {
    scale: 1;
  }
}