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

:root {
  /* Board sizing */
  --board-min: 400px;
  --board-max: 720px;
  --board-size: clamp(var(--board-min), 50vw, var(--board-max));

  /* Clue sizing */
  --clue-min-width: 400px;
  --clue-max-width: 440px;
  --clue-min-height: 320px;
  --clue-max-height: 760px;

  /* Site sizing */
  --site-max-width: 1440px;
  --clue-text: 55ch;

  /* Reserve space so panel doesn't collapse before puzzle initializes */
  --puzzle-dynamic-loading-min-height: 1200px;

  /* Influences board header and clue-wrapper */
  --board-header-lines: 1;
  --board-header-line-height: 1.3;
  --board-header-reserved-height: 1.3em;
}

html {
  font-family: system-ui, "Segoe UI", Roboto, sans-serif;
  overflow-y: scroll;
}

body {
  display: flex;
  flex-direction: column;
  margin: 0;
  min-height: 100vh;
  min-height: 100dvh;
  background: whitesmoke;
}

main {
  max-width: var(--site-max-width);
  margin: 0 auto;
  padding: 0 1rem;
  flex: 1;
}

[hidden] {
  display: none !important;
}

.puzzle-dynamic {
  visibility: hidden;
  min-height: var(--puzzle-dynamic-loading-min-height);
}

.puzzle-dynamic.is-ready {
  /* Reserve space so panel doesn't collapse before puzzle initializes */
  visibility: visible;
  min-height: auto;
}

.puzzle-region {
  display: flex;
  justify-content: center;
  width: 100%;
  flex-direction: column;
}

.toolbar-wrapper {
  display: flex;
  flex-direction: column;
}

.puzzle-toolbar {
  display: inline-flex;
  align-items: center;
  letter-spacing: 0em;
  color: #6b7280;

  user-select: none;
  -webkit-user-select: none;
  touch-action: manipulation;
}

.toolbar-separator {
  margin: 0 0.4rem;
  color: #9ca3af;
  pointer-events: none;
}

.puzzle-toolbar button {
  background: none;
  border: none;
  padding: 0.3rem 0.2rem;
  font: inherit;
  cursor: pointer;
}

.puzzle-toolbar button:hover {
  text-decoration: underline;
}

.puzzle-toolbar .controls-toggle::before {
  content: "\25B6";
  margin-right: 0.1rem;
}

.puzzle-toolbar .controls-toggle[aria-expanded="true"]::before {
  content: "\25BC";
}

.puzzle-toolbar .controls-toggle {
  color: #374151;
}

.puzzle-toolbar .tip-toggle::before {
  content: "\25B6";
  margin-right: 0.1rem;
}

.puzzle-toolbar .tip-toggle[aria-expanded="true"]::before {
  content: "\25BC";
}

.puzzle-toolbar .tip-toggle {
  color: #374151;
}

.puzzle-toolbar .clear-puzzle {
  color: #6b7280;
}

.puzzle-toolbar .clear-puzzle.confirming {
  color: #374151;
}

.controls-mobile {
  display: none;
}

.controls-panel {
  width: 100%;
  margin-bottom: 0.5rem;
  font-size: clamp(0.9rem, 1vw, 1rem);
  line-height: 1.4;
  color: #4b5563;
}

.controls-desktop {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
}

.controls-desktop section {
  min-width: 0;
}

.controls-desktop h3 {
  margin: 0 0 2px 0;
  font-size: 1rem;
  font-weight: 600;
}

.controls-desktop ul {
  margin: 0;
  padding-left: 1.25rem;
}

.controls-desktop li + li {
  margin-top: 0.3rem;
}

.controls-mobile ul {
  margin: 0;
}

.controls-mobile li + li {
  margin-top: 0.3rem;
}

.tip-panel {
  width: 100%;
  margin-bottom: 0.5rem;
  font-size: clamp(0.9rem, 1vw, 1rem);
  line-height: 1.4;
  color: #4b5563;
}

.tip-panel ul {
  margin: 0;
  padding-left: 1rem;
}

.tip-panel li + li {
  margin-top: 0.3rem;
}

.board-title {
  text-align: center;
  font-size: clamp(1.4rem, 2.2vw, 2rem);
  margin-top: 0;
  margin-bottom: clamp(0.5rem, 0.8vw, 0.9rem);
  font-weight: 600;
}

.puzzle-panel {
  display: flex;
  align-items: flex-start;
  gap: 8px;
}

.board-layout {
  width: var(--board-size);
  max-width: 100%;
  min-width: var(--board-min);
  flex: 0 0 auto;
  order: 1;
}

.board-card {
  width: 100%;
  border-radius: 20px;
  background-color: #18181b;
  box-shadow:
    0 1px 2px rgba(0, 0, 0, 0.04),
    0 8px 24px rgba(0, 0, 0, 0.06);
  overflow: hidden;
}

.board {
  width: 100%;
  table-layout: fixed;
  border-collapse: collapse;
  touch-action: manipulation;
  contain: layout paint;
}

.board-header {
  min-height: var(--board-header-reserved-height);
  width: min(100%, var(--clue-text));
  margin: 0 0 0.2rem 0;
  margin-inline: auto;
  text-align: center;

  font-size: clamp(0.9rem, 0.85rem + 0.4vw, 1.05rem);
  font-weight: 600;
  line-height: var(--board-header-line-height);
  letter-spacing: 0.02em;

  display: flex;
  align-items: flex-end;
  justify-content: center;

  overflow: hidden;
}

.board-header-text {
  display: -webkit-box;
  line-clamp: 1;
  -webkit-line-clamp: 1;
  -webkit-box-orient: vertical;

  overflow: hidden;
}

.cell {
  border: 2px solid #18181b;
  background: white;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
  transition:
    background-color 120ms ease,
    box-shadow 120ms ease;
}

.cell.block {
  background: #18181b;
  border-color: #18181b;
  box-shadow: inset 0 0 0 clamp(2px, 0.5vw, 4px) #111;
}

.cell.highlight-placement {
  background: #aeb9db;
}

.cell.highlight-cursor {
  background: #848fbe;
}

.cell .fill {
  position: relative;
  width: 100%;
  font-size: clamp(12px, 1vw, 20px);
  aspect-ratio: 1;
  display: flex;
  justify-content: center;
  align-items: center;
}

.fill .label {
  position: absolute;
  /* Scale clue number offset from 0px at min board size to 2px at max board size. */
  top: clamp(0px, calc((var(--board-size) - 400px) / 160), 2px);
  left: clamp(0px, calc((var(--board-size) - 400px) / 160), 2px);
  pointer-events: none;

  font-size: clamp(14px, calc(var(--board-size) * 0.025), 16px);
  line-height: 1;
  color: #374151;
  font-weight: 600;
}

.fill .letter {
  width: 100%;
  height: 100%;
  border: none;
  padding: 0;

  text-align: center;
  font-size: clamp(16px, 0.9rem + 0.45vw, 22px);
  font-weight: 600;
  line-height: 1;
  text-transform: uppercase;

  background: transparent;
  caret-color: transparent;

  appearance: none;

  user-select: none;
  -webkit-user-select: none;
  -webkit-touch-callout: none;
  -webkit-tap-highlight-color: transparent;
}

.fill .letter:focus {
  outline: none;
}

.fill .letter::selection {
  background: transparent;
}

.mobile-nav {
  display: none;
  order: 3;
}

.clue-wrapper {
  margin-top: var(--board-header-reserved-height);
  background: #f3f3f3;
  border-radius: 20px;
  border: 1px solid rgba(0, 0, 0, 0.04);
  box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.02);
  order: 2;

  flex-shrink: 0;
  width: min(45vw, var(--clue-max-width));
  min-width: var(--clue-min-width);
  height: min(clamp(60vh, calc(24vh + 32vw), 80vh), var(--clue-max-height));
  min-height: var(--clue-min-height);
}

.clue-card {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;

  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  overscroll-behavior-y: auto;
  scrollbar-gutter: stable;

  touch-action: pan-y;

  padding: 14px 10px;
  line-height: 1.4;
}

.todo-wrapper {
  order: 1;
}

.solved-wrapper {
  order: 2;
}

.clue-card :is(h2, h3) {
  margin: 0;
  padding: 0;
}

.clue-card.show-empty .clue-empty {
  display: block;
}

.clue-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;

  font: inherit;
  color: inherit;
  cursor: pointer;
  background: none;
  border: none;

  user-select: none;
  -webkit-user-select: none;

  padding: 0;
  margin: 0;
}

.clue-toggle .clue-label.clue-across::before,
.clue-toggle .clue-label.clue-down::before {
  display: inline-block;
  width: 1ch;
  margin-right: 0.5rem;
}

.clue-toggle .clue-label.clue-across::before {
  content: "\2192";
}

.clue-toggle .clue-label.clue-down::before {
  content: "\2193";
}

.clue-count {
  color: #555;
  font-weight: 500;
  font-variant-numeric: tabular-nums;
}

.clue-list:not([hidden]) {
  list-style: none;
  padding: 0;
  margin: 0.5rem 0 0 0;
}

.clue-card h2 + .clue-section-body {
  margin-top: 0.5rem;
}

/* remove empty clue-list */
.clue-list:empty {
  display: none;
}

/* vertical spacing between clues */
.clue + .clue {
  margin-top: 0.3rem;
}

.clue {
  margin: 0;
  padding: 2px 4px;
  border-radius: 4px;
  list-style: none;

  user-select: none;
  -webkit-user-select: none;
  -webkit-touch-callout: none;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;

  display: grid;
  grid-template-columns: 2ch minmax(0, 1fr) 20px;
  gap: 0;
  width: 100%;
  align-items: start;

  cursor: pointer;
  transition: background-color 120ms ease;
}

.clue:hover {
  background: #e0e4f1;
}

.clue:active {
  background: #b6bddc;
}

.clue.active {
  background: #c9d0e6;
}

.clue-label {
  text-align: right;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.clue-content {
  min-width: 0;
  margin-left: 0.5rem;
}

.clue-text {
  max-width: var(--clue-text);
  overflow-wrap: break-word;
  text-wrap: pretty;
}

.clue-meta {
  white-space: nowrap;
}

.clue-show-answer {
  visibility: hidden;
  pointer-events: none;
  color: #6b7280;
  font-size: 0.9em;
  touch-action: manipulation;
}

.clue-show-answer::before {
  content: "\A";
  white-space: pre;
}

/* Hover that changes interaction causes double click on mobile */
@media (hover: hover) {
  .clue:hover .clue-show-answer {
    visibility: visible;
    pointer-events: auto;
    cursor: pointer;
  }
}

.clue.active .clue-show-answer {
  visibility: visible;
  pointer-events: auto;
  cursor: pointer;
}

.clue-show-answer:hover {
  color: #374151;
}

/* prepend non-breakable space */
.clue-length-label::before {
  content: "\00A0";
}

.clue-length-label {
  color: #6b7280;
  font-size: 0.9em;
}

.clue-copy {
  appearance: none;
  -webkit-appearance: none;

  background: none;
  border: none;
  padding: 0;

  width: 16px;
  height: 16px;

  position: relative;
  cursor: pointer;

  touch-action: manipulation;
}

.clue-copy::before {
  content: "";
  position: absolute;
  inset: -8px;
}

.copy-icon,
.check-icon {
  width: 16px;
  height: 16px;
  display: block;
}

.check-icon {
  transform: scale(1.3);
}

.clue-copy .check-icon {
  display: none;
}

.clue-copy.copied .check-icon {
  display: block;
}

.clue-copy.copied .copy-icon {
  display: none;
}

.clue-empty {
  display: none;
  text-align: center;
  padding: 24px 12px;
  color: #777;
  order: 3;
}

/* Hide clue-count from UX when expanded */
.section-toggle[aria-expanded="true"] .clue-count {
  display: none;
}

.post-puzzle {
  margin-top: 2rem;
}

.puzzle-metadata {
  font-size: 0.9rem;
  color: #6b7280;
  margin-bottom: 0.4rem;
}

/* remove empty items */
.puzzle-metadata .meta-line > :empty {
  display: none;
}

/* add separator between remaining items */
.puzzle-metadata .meta-line > :not(button) + :not(button)::before {
  content: "\00A0\2022\00A0";
}

.puzzle-metadata p {
  margin: 0;
}

.puzzle-url-copy-button {
  margin-left: 0.4rem;
  opacity: 0.55;
  transform: translateY(2px);
}

.puzzle-url-copy-button:hover {
  opacity: 0.9;
}

p.board-desc {
  margin: 0;
}

.board-desc {
  max-width: 60ch;
  line-height: 1.6;
  color: #4b5563;
  overflow-wrap: break-word;
  text-wrap: pretty;
}

.puzzle-link-section {
  margin: 1.5rem 0 0;
}

.puzzle-link-section p {
  margin: 0;
}

.next-puzzle-link {
  word-break: break-word;
}

.next-puzzle-link a {
  color: black;
  font-weight: 600;
  text-decoration: none;
}

.next-puzzle-link + .design-note-link {
  margin-top: 0.4rem;
}

.design-note-link {
  white-space: nowrap;
}

.design-note-link a {
  color: #4b5563;
  font-weight: 500;
  text-decoration: none;
}

.design-note-link a:hover {
  color: #1f2937;
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
}

.solution-panel {
  width: clamp(320px, 28vw, 460px);
  max-width: 100%;
  margin-top: 0.5rem;
}

.solution-toggle {
  cursor: pointer;
  font-weight: 600;
  padding: 4px 0;
  border-radius: 8px;
}

.solution-toggle:hover {
  background: #f2f2f2;
}

.solution-json {
  background: #1e1e1e;
  color: #ce9178;
  padding: 1rem;
  margin-top: 0.5rem;
  border-radius: 8px;
  overflow-x: auto;
  font-family: ui-monospace, monospace;
  font-size: 0.85rem;
  line-height: 1.4;
  border: 1px solid #2d2d2d;
}

@keyframes success-pulse {
  0% {
    background-color: var(--cell-bg);
    transform: translateY(0);
  }
  30% {
    background-color: #dbe3ff;
    transform: translateY(-1px);
  }
  70% {
    background-color: #dbe3ff;
    transform: translateY(-1px);
  }
  100% {
    background-color: var(--cell-bg);
    transform: translateY(0);
  }
}
.placement-success {
  transform-origin: center;
  animation: success-pulse 300ms ease-out;
}

@keyframes error-shake {
  0% {
    transform: translateX(0);
  }
  20% {
    transform: translateX(-3px);
  }
  40% {
    transform: translateX(3px);
  }
  60% {
    transform: translateX(-3px);
  }
  80% {
    transform: translateX(2px);
  }
  100% {
    transform: translateX(0);
  }
}
.placement-error {
  transform-origin: center;
  animation: error-shake 240ms ease-out;
}

@keyframes direction-reject {
  0% {
    background-color: transparent;
  }
  30% {
    background-color: rgba(132, 143, 190, 0.7);
  }
  70% {
    background-color: rgba(132, 143, 190, 0.7);
  }
  100% {
    background-color: transparent;
  }
}

.direction-reject {
  animation: direction-reject 200ms ease-out;
}

/* Large desktop */
@media (min-width: 1800px) {
  :root {
    --board-max: 780px;
    --clue-max-height: 800px;
  }
}

/* Tablet / Mobile */
@media (max-width: 900px) {
  :root {
    --clue-max-width: 600px;
    --puzzle-dynamic-loading-min-height: 1800px;
    --board-size: clamp(var(--board-min), 90vw, var(--board-max));
  }

  .board-title {
    max-width: 24ch;
    margin-inline: auto;
    text-align: center;
    text-wrap: balance;
  }

  .toolbar-wrapper {
    align-items: center;
  }

  .tip-panel ul {
    padding-left: revert;
  }

  .puzzle-panel {
    flex-direction: column;
    align-items: center;
  }

  .clue-wrapper {
    margin-top: 0;
    width: min(90vw, var(--clue-max-width));
    height: 50vh;
    order: 1;
  }

  .board-layout {
    order: 2;
  }

  .mobile-nav {
    display: flex;
    gap: 12px;
  }

  .mobile-nav button {
    appearance: none;
    border: 0;
    background: transparent;
    color: inherit;
    font: inherit;
    font-size: clamp(1.2rem, 1rem + 0.6vw, 1.4rem);

    padding: 4px 6px;
    cursor: pointer;
    touch-action: manipulation;
  }

  .mobile-nav button:active {
    opacity: 0.6;
  }

  .solved-wrapper {
    order: 1;
  }

  .todo-wrapper {
    order: 2;
  }

  .instructions-desktop,
  .controls-desktop {
    display: none;
  }

  .controls-mobile {
    display: block;
  }
}