@import "fonts/clear-sans.css";

html, body {
  margin: 0;
  padding: 0;
  background: #faf8ef;
  color: #776E65;
  font-family: "Clear Sans", "Helvetica Neue", Arial, sans-serif;
  font-size: 1.125rem;
}

body {
  padding: 4rem 16px;
}

/* Narrow screens: less empty space above the board. */
@media (max-width: 860px) {
  body {
    padding-top: max(16px, env(safe-area-inset-top));
  }
}

*, *::before, *::after {
  box-sizing: border-box;
}

.container {
  width: min(100%, 40rem);
  margin: 0 auto;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.hidden,
[hidden] {
  display: none !important;
}

p {
  margin-top: 0;
  margin-bottom: 10px;
  line-height: 1.65;
}

a {
  color: #776E65;
  font-weight: bold;
  text-decoration: underline;
  cursor: pointer;
}

strong.important {
  text-transform: uppercase;
}

hr {
  border: none;
  border-bottom: 1px solid #d8d4d0;
  margin-top: 20px;
  margin-bottom: 30px;
}

/* ---------- Heading and scores ---------- */

.heading {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}

h1.title {
  font-size: clamp(2.25rem, 10vw, 3.5rem);
  font-weight: bold;
  line-height: 1.1;
  margin: 0;
}

@keyframes move-up {
  0% {
    top: 25px;
    opacity: 1;
  }
  100% {
    top: -50px;
    opacity: 0;
  }
}

.scores-container {
  display: flex;
  gap: 6px;
}

.score-container, .best-container {
  position: relative;
  display: flex;
  align-items: flex-end;
  justify-content: center;
  min-width: 4.25rem;
  height: 56px;
  padding: 0 12px 6px;
  border-radius: 3px;
  background: #bbada0;
  color: white;
  font-size: 21px;
  line-height: 1.2;
  font-weight: bold;
  text-align: center;
}

.score-container:after, .best-container:after {
  position: absolute;
  width: 100%;
  top: 8px;
  left: 0;
  text-transform: uppercase;
  font-size: 13px;
  line-height: 13px;
  text-align: center;
  color: #eee4da;
}

.score-container .score-addition, .best-container .score-addition {
  position: absolute;
  right: 30px;
  font-size: 21px;
  line-height: 21px;
  font-weight: bold;
  color: rgba(119, 110, 101, 0.9);
  z-index: 100;
  animation: move-up 250ms ease-in both;
}

.score-container:after {
  content: "Score";
}

.best-container:after {
  content: "Best";
}

.game-intro {
  margin: 12px 0;
}

/* ---------- Mode, size and actions ---------- */

.toolbar {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px;
}

.segmented {
  display: inline-flex;
  margin: 0;
  padding: 3px;
  border: 0;
  border-radius: 6px;
  background: #bbada0;
}

.segmented input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.segmented label {
  display: grid;
  place-items: center;
  min-height: 38px;
  padding: 0 12px;
  border-radius: 4px;
  color: #f9f6f2;
  font-size: 16px;
  font-weight: bold;
  white-space: nowrap;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

.segmented input:checked + label {
  background: #8f7a66;
}

.segmented input:focus-visible + label {
  outline: 2px solid #776E65;
  outline-offset: 2px;
}

.segmented input:disabled + label {
  opacity: 0.5;
  cursor: not-allowed;
}

.actions {
  display: flex;
  gap: 8px;
  margin-top: 10px;
}

.restart-button,
.action-button,
.game-container .game-message .lower > * {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  min-height: 44px;
  padding: 0 16px;
  border: 0;
  border-radius: 3px;
  background: #8f7a66;
  color: #f9f6f2;
  font: inherit;
  font-weight: bold;
  text-decoration: none;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

.restart-button {
  margin-right: auto;
}

.restart-button:hover,
.action-button:hover:not(:disabled),
.game-container .game-message .lower > *:hover {
  background: #9b8773;
}

.restart-button:focus-visible,
.action-button:focus-visible {
  outline: 2px solid #776E65;
  outline-offset: 2px;
}

.action-button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.badge {
  min-width: 1.4em;
  padding: 0 4px;
  border-radius: 999px;
  background: rgba(249, 246, 242, 0.25);
  font-size: 0.8em;
  line-height: 1.4;
}

.status {
  min-height: 1.65em;
  margin: 8px 0 0;
  font-weight: bold;
}

.status[data-kind="hint"] {
  color: #f65e3b;
}

.note {
  margin: 4px 0 0;
  font-size: 0.85em;
}

.model-status progress {
  width: 100%;
  accent-color: #8f7a66;
}

.watching-ai .game-intro::after {
  content: " The AI is playing.";
  font-weight: bold;
}

/* ---------- Board ---------- */

@keyframes fade-in {
  0% {
    opacity: 0;
  }
  100% {
    opacity: 1;
  }
}

.game-container {
  --n: 4;
  --gap: calc(60px / var(--n));
  position: relative;
  width: min(100%, 500px);
  aspect-ratio: 1;
  margin: 12px auto 0;
  padding: var(--gap);
  border-radius: 6px;
  background: #bbada0;
  cursor: default;
  user-select: none;
  -webkit-user-select: none;
  touch-action: none;
  container-type: inline-size;
}

@media (max-width: 520px) {
  .game-container {
    --gap: calc(40px / var(--n));
  }
}

.grid-container,
.tile-container {
  position: absolute;
  inset: var(--gap);
}

.grid-container {
  z-index: 1;
  display: grid;
  grid-template-columns: repeat(var(--n), 1fr);
  grid-auto-rows: 1fr;
  gap: var(--gap);
}

.grid-row {
  display: contents;
}

.grid-cell {
  border-radius: 3px;
  background: rgba(238, 228, 218, 0.35);
}

/* The layer spans the board; only the tiles themselves take clicks (the editor needs the cells). */
.tile-container {
  z-index: 2;
  pointer-events: none;
}

.tile {
  pointer-events: auto;
}

.tile {
  --size: calc((100cqi - (var(--n) + 1) * var(--gap)) / var(--n));
  position: absolute;
  top: 0;
  left: 0;
  width: calc((100% - (var(--n) - 1) * var(--gap)) / var(--n));
  aspect-ratio: 1;
  transform: translate(calc(var(--x, 0) * (100% + var(--gap))), calc(var(--y, 0) * (100% + var(--gap))));
  transition: transform 100ms ease-in-out;
}

.tile .tile-inner {
  display: grid;
  place-items: center;
  width: 100%;
  height: 100%;
  border-radius: 3px;
  background: #eee4da;
  font-weight: bold;
  font-size: calc(var(--size) * 0.5);
  line-height: 1;
  z-index: 10;
}

.tile.tile-digits-3 .tile-inner {
  font-size: calc(var(--size) * 0.4);
}

.tile.tile-digits-4 .tile-inner {
  font-size: calc(var(--size) * 0.31);
}

.tile.tile-super .tile-inner {
  font-size: calc(var(--size) * 0.25);
}

.tile.tile-2 .tile-inner {
  background: #eee4da;
}

.tile.tile-4 .tile-inner {
  background: #eee1c9;
}

.tile.tile-8 .tile-inner {
  color: #f9f6f2;
  background: #f3b27a;
}

.tile.tile-16 .tile-inner {
  color: #f9f6f2;
  background: #f69664;
}

.tile.tile-32 .tile-inner {
  color: #f9f6f2;
  background: #f77c5f;
}

.tile.tile-64 .tile-inner {
  color: #f9f6f2;
  background: #f75f3b;
}

.tile.tile-128 .tile-inner {
  color: #f9f6f2;
  background: #edd073;
  box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0.238), inset 0 0 0 1px rgba(255, 255, 255, 0.143);
}

.tile.tile-256 .tile-inner {
  color: #f9f6f2;
  background: #edcc62;
  box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0.317), inset 0 0 0 1px rgba(255, 255, 255, 0.19);
}

.tile.tile-512 .tile-inner {
  color: #f9f6f2;
  background: #edc950;
  box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0.397), inset 0 0 0 1px rgba(255, 255, 255, 0.238);
}

.tile.tile-1024 .tile-inner {
  color: #f9f6f2;
  background: #edc53f;
  box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0.476), inset 0 0 0 1px rgba(255, 255, 255, 0.286);
}

.tile.tile-2048 .tile-inner {
  color: #f9f6f2;
  background: #edc22e;
  box-shadow: 0 0 30px 10px rgba(243, 215, 116, 0.556), inset 0 0 0 1px rgba(255, 255, 255, 0.333);
}

.tile.tile-super .tile-inner {
  color: #f9f6f2;
  background: #3c3a33;
}

@keyframes appear {
  0% {
    opacity: 0;
    transform: scale(0);
  }
  100% {
    opacity: 1;
    transform: scale(1);
  }
}

.tile-new .tile-inner {
  animation: appear 200ms ease 100ms backwards;
}

@keyframes pop {
  0% {
    transform: scale(0);
  }
  50% {
    transform: scale(1.2);
  }
  100% {
    transform: scale(1);
  }
}

.tile-merged .tile-inner {
  z-index: 20;
  animation: pop 200ms ease 100ms backwards;
}

@media (prefers-reduced-motion: reduce) {
  .tile {
    transition: none;
  }

  .tile-new .tile-inner,
  .tile-merged .tile-inner {
    animation: none;
  }
}

/* ---------- Win / lose overlay ---------- */

.game-container .game-message {
  display: none;
  position: absolute;
  inset: 0;
  z-index: 100;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8cqi;
  border-radius: 6px;
  background: rgba(238, 228, 218, 0.5);
  text-align: center;
  animation: fade-in 800ms ease 1200ms both;
}

.game-container .game-message p {
  margin: 0;
  font-size: 12cqi;
  font-weight: bold;
  line-height: 1;
}

.game-container .game-message .lower {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
}

.game-container .game-message .keep-playing-button,
.game-container .game-message .undo-last-button {
  display: none;
}

.game-container .game-message.game-won {
  background: rgba(237, 194, 46, 0.5);
  color: #f9f6f2;
}

.game-container .game-message.game-won .keep-playing-button,
.game-container .game-message.game-over .undo-last-button:not(:disabled) {
  display: inline-flex;
}

.game-container .game-message.game-won, .game-container .game-message.game-over {
  display: flex;
}

/* ---------- AI settings drawer ---------- */

.game-explanation {
  margin-top: 20px;
}

.ai-drawer {
  margin-top: 16px;
  border-radius: 6px;
  background: #eee4da;
}

.ai-drawer summary {
  min-height: 44px;
  padding: 10px 16px;
  font-weight: bold;
  cursor: pointer;
}

.ai-drawer[open] summary {
  border-bottom: 1px solid #d8d4d0;
}

#controlsContainer {
  padding: 4px 16px 16px;
}

#controlsContainer h3 {
  margin: 1rem 0 0.25rem;
}

#controlsContainer label {
  line-height: 1.8;
}

#pauseTime {
  width: 6rem;
  font: inherit;
}

input:not(:checked) + label + small.description {
  display: none;
}

/* ---------- Editor and replay pages ---------- */

.above-game {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  margin-top: 12px;
}

.above-game .restart-button {
  flex: none;
  margin-right: 0;
}

#gameRecordDisplay {
  background: #eee7c8;
  margin: 1rem 0;
  padding: 0.75rem 0.5rem;
  overflow-x: hidden;
  font-family: monospace;
  white-space: nowrap;
}

span.record-display.highlighted {
  background: #d6c57a;
}

span.record-display {
  cursor: pointer;
}

span.record-display:hover:not(.highlighted) {
  background: #e8dfb5;
}

#replayControls {
  width: min(520px, 100%);
  margin: 1rem auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 4px;
}

#gameRecordContainer {
  text-align: center;
}

#gameRecord {
  max-width: 100%;
}

.game-record-control {
  display: inline-block;
  padding: 10px;
  border-radius: 3px;
  background: #8f7a66;
  color: #f9f6f2;
  line-height: 19px;
  text-decoration: none;
}

.game-record-control:hover {
  background: #9b8773;
}

@media (max-width: 520px) {
  html, body {
    font-size: 1rem;
  }

  .segmented label {
    padding: 0 9px;
    font-size: 15px;
  }

  .restart-button,
  .action-button {
    padding: 0 12px;
  }

  #replayControls {
    flex-wrap: wrap;
    justify-content: center;
  }

  #gameRecordContainer {
    flex-basis: 100%;
    order: -1;
  }
}

/* ---------- Phones (game page only) ----------
   The board is capped at the height left below the controls (--board-max,
   measured in js/index.js), so the whole board shows without scrolling. */
.play-page {
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}

.play-page .game-container {
  width: min(100%, 500px, var(--board-max, 500px));
  overscroll-behavior: contain;
}

@media (max-width: 600px) {
  .play-page {
    padding-left: max(12px, env(safe-area-inset-left));
    padding-right: max(12px, env(safe-area-inset-right));
    padding-bottom: max(16px, env(safe-area-inset-bottom));
  }

  .play-page .heading {
    flex-wrap: nowrap;
  }

  .play-page h1.title {
    font-size: clamp(1.75rem, 9vw, 3.5rem);
  }

  .play-page .score-container,
  .play-page .best-container {
    min-width: 3.75rem;
    height: 50px;
    padding: 0 8px 5px;
  }

  .play-page .segmented label {
    min-height: 44px;
    padding: 0 10px;
  }

  .play-page .actions {
    margin-top: 8px;
  }

  .play-page .status {
    margin-top: 4px;
  }

  .play-page .game-container {
    margin-top: 6px;
  }
}

/* Short portrait screens: the intro line makes way for the board. */
@media (max-width: 600px) and (max-height: 760px) {
  .play-page .game-intro {
    display: none;
  }

  .play-page .heading {
    margin-bottom: 10px;
  }
}

@media (max-width: 360px) {
  .play-page .segmented label {
    padding: 0 8px;
    font-size: 14px;
  }

  .play-page .restart-button,
  .play-page .action-button {
    padding: 0 10px;
  }
}

/* Landscape phones: controls on the left, the board on the right at full height. */
@media (orientation: landscape) and (max-height: 560px) {
  .play-page {
    padding: max(12px, env(safe-area-inset-top)) max(16px, env(safe-area-inset-right)) max(12px, env(safe-area-inset-bottom)) max(16px, env(safe-area-inset-left));
  }

  .play-page .container {
    width: min(100%, 62rem);
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    column-gap: 20px;
    align-items: start;
  }

  .play-page .container > * {
    grid-column: 1;
  }

  .play-page .game-container {
    grid-column: 2;
    grid-row: 1 / span 7;
    width: min(500px, var(--board-max, 300px), 58vw);
    margin: 0;
  }

  .play-page h1.title {
    font-size: clamp(1.5rem, 4.5vw, 3rem);
    white-space: nowrap;
  }

  .play-page .game-intro {
    margin: 8px 0;
  }

  .play-page .actions {
    flex-wrap: wrap;
  }

  .play-page .heading {
    flex-wrap: wrap;
  }
}

@media (orientation: landscape) and (max-height: 420px) {
  .play-page .game-intro {
    display: none;
  }

  .play-page .heading {
    margin-bottom: 8px;
  }

  .play-page .segmented label {
    min-height: 44px;
  }
}