/*
 * Sudoku Tools application styles.
 *
 * The Toolbox shell owns the base theme tokens. Everything here derives from
 * those tokens so standalone, connected, light, dark, and system appearances
 * remain visually aligned.
 */

:root {
  --sudoku-success: #15735a;
  --sudoku-warning: #9a5b0b;
  --sudoku-info: #3560a8;
  --sudoku-board-radius: clamp(0.55rem, 1.2vw, 0.9rem);
}

html {
  min-width: 20rem;
  min-height: 100%;
  background: var(--toolbox-background);
  scrollbar-gutter: stable;
}

body {
  min-width: 20rem;
  min-height: 100vh;
  margin: 0;
  background: var(--toolbox-background);
  color: var(--toolbox-text);
  font-family: var(--toolbox-font);
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

#root {
  min-height: 100vh;
}

::selection {
  background: color-mix(in srgb, var(--toolbox-focus) 44%, transparent);
  color: var(--toolbox-text);
}

.toolbox-shell__main {
  width: min(100%, 90rem);
  padding: clamp(0.75rem, 1.7vw, 1.5rem);
}

.sudoku-workbench,
.modal,
.fatal-error {
  --sudoku-success: color-mix(in srgb, #06805d 78%, var(--toolbox-text));
  --sudoku-warning: color-mix(in srgb, #bf730a 78%, var(--toolbox-text));
  --sudoku-info: color-mix(in srgb, #3268bd 76%, var(--toolbox-text));
  --sudoku-line: color-mix(
    in srgb,
    var(--toolbox-text) 38%,
    var(--toolbox-border)
  );
  --sudoku-line-strong: color-mix(
    in srgb,
    var(--toolbox-text) 78%,
    var(--toolbox-border)
  );
  color: var(--toolbox-text);
  font-family: var(--toolbox-font);
}

/* Help is mounted next to the shell, so bridge its selected dark theme. */
body:has(.toolbox-shell[data-toolbox-theme="dark"]) .modal,
body:has(.toolbox-shell[data-toolbox-theme="dark"]) .fatal-error {
  color-scheme: dark;
  --toolbox-background: #0f1422;
  --toolbox-surface: #171d2d;
  --toolbox-surface-soft: #20283a;
  --toolbox-text: #edf1fb;
  --toolbox-muted: #a9b3ca;
  --toolbox-border: #303a50;
  --toolbox-accent: #a9b7ff;
  --toolbox-accent-hover: #c3ccff;
  --toolbox-accent-soft: #252f55;
  --toolbox-accent-contrast: #11182a;
  --toolbox-focus: #66cdbd;
  --toolbox-danger: #ff8fa3;
  --toolbox-shadow: 0 14px 42px rgb(0 0 0 / 24%);
}

@media (prefers-color-scheme: dark) {
  body:has(.toolbox-shell[data-toolbox-theme="system"]) .modal,
  body:has(.toolbox-shell[data-toolbox-theme="system"]) .fatal-error {
    color-scheme: dark;
    --toolbox-background: #0f1422;
    --toolbox-surface: #171d2d;
    --toolbox-surface-soft: #20283a;
    --toolbox-text: #edf1fb;
    --toolbox-muted: #a9b3ca;
    --toolbox-border: #303a50;
    --toolbox-accent: #a9b7ff;
    --toolbox-accent-hover: #c3ccff;
    --toolbox-accent-soft: #252f55;
    --toolbox-accent-contrast: #11182a;
    --toolbox-focus: #66cdbd;
    --toolbox-danger: #ff8fa3;
    --toolbox-shadow: 0 14px 42px rgb(0 0 0 / 24%);
  }
}

/* Shared type and control language */

.sudoku-workbench :where(h1, h2, h3),
.modal :where(h2, h3),
.fatal-error :where(h1, h2) {
  margin: 0;
  color: var(--toolbox-text);
  font-weight: 760;
  letter-spacing: -0.027em;
  line-height: 1.16;
}

.sudoku-workbench h1 {
  font-size: clamp(1.65rem, 3.2vw, 2.65rem);
}

.sudoku-workbench h2,
.modal h2 {
  font-size: clamp(1.25rem, 2.1vw, 1.65rem);
}

.sudoku-workbench h3,
.modal h3 {
  font-size: 1rem;
  letter-spacing: -0.015em;
}

.sudoku-workbench :where(p, ul, ol, dl),
.modal :where(p, ul, ol, dl),
.fatal-error p {
  margin-block: 0;
}

.sudoku-workbench p,
.modal p,
.fatal-error p {
  line-height: 1.58;
}

.stack {
  display: grid;
  align-content: start;
  gap: 1rem;
}

.eyebrow {
  margin: 0 0 0.28rem !important;
  color: var(--toolbox-accent);
  font-size: 0.68rem;
  font-weight: 800;
  letter-spacing: 0.115em;
  line-height: 1.35 !important;
  text-transform: uppercase;
}

.muted {
  color: var(--toolbox-muted);
  font-size: 0.88rem;
}

.sr-only {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

:where(.sudoku-workbench, .modal, .fatal-error)
  :where(button, input, select, textarea) {
  font: inherit;
}

:where(.sudoku-workbench, .modal, .fatal-error) button {
  min-height: 2.65rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  padding: 0.6rem 0.85rem;
  border: 1px solid var(--toolbox-border);
  border-radius: 0.62rem;
  background: var(--toolbox-surface);
  box-shadow: 0 1px 1px rgb(20 30 60 / 4%);
  color: var(--toolbox-text);
  font-size: 0.82rem;
  font-weight: 700;
  line-height: 1.2;
  text-align: center;
  cursor: pointer;
  touch-action: manipulation;
  transition:
    border-color 140ms ease,
    background-color 140ms ease,
    color 140ms ease,
    box-shadow 140ms ease,
    transform 140ms ease;
  -webkit-tap-highlight-color: transparent;
}

:where(.sudoku-workbench, .modal, .fatal-error) button.is-active,
:where(.sudoku-workbench, .modal) button[aria-pressed="true"],
:where(.sudoku-workbench, .modal) [role="tab"][aria-selected="true"],
:where(.sudoku-workbench, .modal) .primary-button,
.fatal-error .primary-button {
  border-color: var(--toolbox-accent);
  background: var(--toolbox-accent);
  box-shadow: 0 0.2rem 0.7rem
    color-mix(in srgb, var(--toolbox-accent) 16%, transparent);
  color: var(--toolbox-accent-contrast);
}

:where(.sudoku-workbench, .modal, .fatal-error) button:disabled {
  box-shadow: none;
  cursor: not-allowed;
  opacity: 0.46;
}

:where(.sudoku-workbench, .modal, .fatal-error) .text-button {
  min-height: 2.1rem;
  padding: 0.3rem 0.45rem;
  border-color: transparent;
  background: transparent;
  box-shadow: none;
}

:where(.sudoku-workbench, .modal, .fatal-error) .danger {
  color: var(--toolbox-danger);
}

:where(.sudoku-workbench, .modal, .fatal-error)
  button.danger:not(.text-button) {
  border-color: color-mix(
    in srgb,
    var(--toolbox-danger) 34%,
    var(--toolbox-border)
  );
  background: color-mix(
    in srgb,
    var(--toolbox-danger) 7%,
    var(--toolbox-surface)
  );
}

:where(.sudoku-workbench, .modal)
  :where(input:not([type="checkbox"]):not([type="radio"]), select, textarea) {
  width: 100%;
  min-width: 0;
  min-height: 2.65rem;
  padding: 0.58rem 0.7rem;
  border: 1px solid var(--toolbox-border);
  border-radius: 0.58rem;
  outline: none;
  background: var(--toolbox-surface);
  box-shadow: inset 0 1px 1px rgb(20 30 60 / 3%);
  color: var(--toolbox-text);
  line-height: 1.35;
  transition:
    border-color 140ms ease,
    box-shadow 140ms ease,
    background-color 140ms ease;
}

:where(.sudoku-workbench, .modal) textarea {
  min-height: 5.75rem;
  resize: vertical;
}

:where(.sudoku-workbench, .modal) select {
  padding-right: 2rem;
  cursor: pointer;
}

:where(.sudoku-workbench, .modal) input::placeholder,
:where(.sudoku-workbench, .modal) textarea::placeholder {
  color: color-mix(in srgb, var(--toolbox-muted) 72%, transparent);
}

:where(.sudoku-workbench, .modal) input:disabled,
:where(.sudoku-workbench, .modal) select:disabled,
:where(.sudoku-workbench, .modal) textarea:disabled {
  cursor: not-allowed;
  opacity: 0.58;
}

:where(.sudoku-workbench, .modal) input[type="checkbox"],
:where(.sudoku-workbench, .modal) input[type="radio"] {
  width: 1.05rem;
  height: 1.05rem;
  flex: none;
  margin: 0;
  accent-color: var(--toolbox-accent);
}

:where(.sudoku-workbench, .modal) label {
  min-width: 0;
  display: grid;
  gap: 0.38rem;
  color: var(--toolbox-muted);
  font-size: 0.74rem;
  font-weight: 720;
  letter-spacing: 0.015em;
  line-height: 1.35;
}

:where(.sudoku-workbench, .modal) .check-row {
  min-height: 2rem;
  display: flex;
  align-items: center;
  gap: 0.55rem;
  color: var(--toolbox-text);
  font-size: 0.82rem;
  font-weight: 620;
  letter-spacing: 0;
  cursor: pointer;
}

:where(.sudoku-workbench, .modal)
  :where(button, input, select, textarea, [tabindex]):focus-visible,
.fatal-error button:focus-visible {
  outline: 3px solid
    color-mix(in srgb, var(--toolbox-focus) 74%, var(--toolbox-accent));
  outline-offset: 2px;
}

:where(.sudoku-workbench, .modal)
  :where(
    input:not([type="checkbox"]):not([type="radio"]),
    select,
    textarea
  ):focus-visible {
  border-color: color-mix(
    in srgb,
    var(--toolbox-focus) 70%,
    var(--toolbox-accent)
  );
  outline: none;
  box-shadow: 0 0 0 3px
    color-mix(in srgb, var(--toolbox-focus) 22%, transparent);
}

@media (hover: hover) {
  :where(.sudoku-workbench, .modal, .fatal-error)
    button:not(:disabled):not(.sudoku-cell):hover {
    border-color: color-mix(
      in srgb,
      var(--toolbox-accent) 46%,
      var(--toolbox-border)
    );
    background: var(--toolbox-accent-soft);
    color: var(--toolbox-accent);
  }

  :where(.sudoku-workbench, .modal, .fatal-error)
    button.is-active:not(:disabled):hover,
  :where(.sudoku-workbench, .modal)
    button[aria-pressed="true"]:not(:disabled):hover,
  :where(.sudoku-workbench, .modal)
    [role="tab"][aria-selected="true"]:not(:disabled):hover,
  :where(.sudoku-workbench, .modal) .primary-button:not(:disabled):hover,
  .sudoku-workbench .hero-actions button:first-child:not(:disabled):hover,
  .fatal-error .primary-button:not(:disabled):hover {
    border-color: var(--toolbox-accent-hover);
    background: var(--toolbox-accent-hover);
    color: var(--toolbox-accent-contrast);
  }

  :where(.sudoku-workbench, .modal, .fatal-error)
    button:not(:disabled):not(.sudoku-cell):active {
    transform: translateY(1px);
  }

  :where(.sudoku-workbench, .modal, .fatal-error) .text-button:hover {
    border-color: transparent;
    background: var(--toolbox-surface-soft);
  }

  :where(.sudoku-workbench, .modal, .fatal-error) .danger:hover {
    background: color-mix(
      in srgb,
      var(--toolbox-danger) 10%,
      var(--toolbox-surface)
    ) !important;
    color: var(--toolbox-danger) !important;
  }
}

/* Workbench shell */

.sudoku-workbench {
  width: min(100%, 90rem);
  display: grid;
  gap: clamp(0.8rem, 1.5vw, 1.2rem);
  margin-inline: auto;
}

.workbench-hero {
  position: relative;
  isolation: isolate;
  min-width: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem 2rem;
  overflow: hidden;
  padding: clamp(1rem, 2.3vw, 1.75rem);
  border: 1px solid var(--toolbox-border);
  border-radius: calc(var(--toolbox-radius) + 0.25rem);
  background:
    radial-gradient(
      circle at 82% 12%,
      color-mix(in srgb, var(--toolbox-focus) 18%, transparent),
      transparent 30%
    ),
    linear-gradient(
      135deg,
      color-mix(
        in srgb,
        var(--toolbox-accent-soft) 72%,
        var(--toolbox-surface)
      ),
      var(--toolbox-surface) 62%
    );
  box-shadow: var(--toolbox-shadow);
}

.workbench-hero::after {
  position: absolute;
  z-index: -1;
  right: clamp(-2.5rem, -1vw, -0.75rem);
  bottom: clamp(-4.8rem, -5vw, -2.75rem);
  width: clamp(10rem, 20vw, 17rem);
  aspect-ratio: 1;
  border: 2px solid color-mix(in srgb, var(--toolbox-accent) 11%, transparent);
  background-image:
    linear-gradient(
      to right,
      transparent 32.8%,
      color-mix(in srgb, var(--toolbox-accent) 10%, transparent) 33%,
      color-mix(in srgb, var(--toolbox-accent) 10%, transparent) 33.7%,
      transparent 34%,
      transparent 66.1%,
      color-mix(in srgb, var(--toolbox-accent) 10%, transparent) 66.3%,
      color-mix(in srgb, var(--toolbox-accent) 10%, transparent) 67%,
      transparent 67.2%
    ),
    linear-gradient(
      to bottom,
      transparent 32.8%,
      color-mix(in srgb, var(--toolbox-accent) 10%, transparent) 33%,
      color-mix(in srgb, var(--toolbox-accent) 10%, transparent) 33.7%,
      transparent 34%,
      transparent 66.1%,
      color-mix(in srgb, var(--toolbox-accent) 10%, transparent) 66.3%,
      color-mix(in srgb, var(--toolbox-accent) 10%, transparent) 67%,
      transparent 67.2%
    );
  border-radius: 1.5rem;
  content: "";
  opacity: 0.9;
  transform: rotate(10deg);
}

.hero-copy {
  min-width: 0;
  max-width: 51rem;
}

.hero-copy > p:not(.eyebrow) {
  max-width: 64ch;
  margin-top: 0.55rem;
  color: var(--toolbox-muted);
  font-size: clamp(0.86rem, 1.2vw, 0.96rem);
}

.hero-actions,
.action-row,
.toolbar-group,
.export-actions {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.55rem;
}

.hero-actions {
  position: relative;
  z-index: 1;
  justify-content: flex-end;
}

.hero-actions button:first-child {
  border-color: var(--toolbox-accent);
  background: var(--toolbox-accent);
  color: var(--toolbox-accent-contrast);
}

.workspace-tabs,
.subtabs,
.mode-switcher {
  display: grid;
  gap: 0.3rem;
  padding: 0.32rem;
  border: 1px solid var(--toolbox-border);
  border-radius: 0.78rem;
  background: color-mix(
    in srgb,
    var(--toolbox-surface-soft) 78%,
    var(--toolbox-surface)
  );
}

.workspace-tabs {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.workspace-tabs button,
.subtabs button,
.mode-switcher button {
  min-height: 2.45rem;
  border-color: transparent;
  background: transparent;
  box-shadow: none;
  color: var(--toolbox-muted);
}

.workspace-tabs button.is-active,
.workspace-tabs button[aria-selected="true"],
.subtabs button.is-active,
.mode-switcher button.is-active {
  border-color: var(--toolbox-border);
  background: var(--toolbox-surface);
  box-shadow: 0 0.15rem 0.55rem rgb(20 30 60 / 8%);
  color: var(--toolbox-accent);
}

.workbench-status {
  min-height: 2.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.6rem 1rem;
  padding: 0.35rem 0.2rem;
  color: var(--toolbox-muted);
  font-size: 0.78rem;
}

.timer-display {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.3rem 0.55rem;
  border: 1px solid var(--toolbox-border);
  border-radius: 999px;
  background: var(--toolbox-surface);
  color: var(--toolbox-text);
  font-family:
    ui-monospace, SFMono-Regular, Consolas, "Liberation Mono", monospace;
  font-size: 0.78rem;
  font-variant-numeric: tabular-nums;
  font-weight: 720;
  letter-spacing: 0.04em;
}

.workbench-grid {
  min-width: 0;
  display: grid;
  grid-template-columns: minmax(0, 1.65fr) minmax(19.5rem, 0.82fr);
  align-items: start;
  gap: clamp(0.85rem, 1.6vw, 1.35rem);
}

.workbench-grid--helpers {
  grid-template-columns: minmax(24rem, 0.92fr) minmax(31rem, 1.08fr);
}

.board-column,
.side-panel,
.play-panel,
.setter-panel,
.solve-workspace,
.helpers-workspace {
  min-width: 0;
}

.board-column {
  display: grid;
  align-content: start;
  gap: 0.75rem;
}

.board-toolbar {
  min-height: 2.8rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.55rem 1rem;
}

.board-toolbar > span {
  color: var(--toolbox-muted);
  font-family:
    ui-monospace, SFMono-Regular, Consolas, "Liberation Mono", monospace;
  font-size: 0.75rem;
  font-variant-numeric: tabular-nums;
}

.select-wrap {
  min-width: min(100%, 11rem);
}

.select-wrap select {
  min-height: 2.45rem !important;
}

.board-surface,
.side-panel {
  border: 1px solid var(--toolbox-border);
  border-radius: calc(var(--toolbox-radius) + 0.2rem);
  background: var(--toolbox-surface);
  box-shadow: var(--toolbox-shadow);
}

.board-surface {
  position: relative;
  display: grid;
  justify-items: center;
  padding: clamp(0.5rem, 1.7vw, 1.15rem);
  overflow: hidden;
}

.board-surface.is-paused .sudoku-board-frame {
  opacity: 0.72;
  filter: saturate(0.6);
}

.side-panel {
  padding: clamp(0.85rem, 1.7vw, 1.2rem);
}

.paused-cover {
  position: absolute;
  z-index: 12;
  inset: 0;
  display: grid;
  align-content: center;
  justify-items: center;
  gap: 0.65rem;
  padding: 1.5rem;
  border-radius: inherit;
  background: color-mix(in srgb, var(--toolbox-surface) 78%, transparent);
  color: var(--toolbox-text);
  text-align: center;
  backdrop-filter: blur(12px);
}

.paused-cover::before {
  width: 3.5rem;
  height: 3.5rem;
  display: grid;
  place-items: center;
  border: 1px solid var(--toolbox-border);
  border-radius: 50%;
  background: var(--toolbox-surface);
  box-shadow: var(--toolbox-shadow);
  color: var(--toolbox-accent);
  content: "Ⅱ";
  font-size: 1.25rem;
  font-weight: 800;
}

.board-meta {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.55rem 1rem;
  color: var(--toolbox-muted);
  font-size: 0.78rem;
}

.board-meta .rule-card {
  flex: 1 1 100%;
}

.rule-card,
.panel-section,
.helper-card,
.analysis-summary,
.logical-results {
  min-width: 0;
  padding: clamp(0.8rem, 1.45vw, 1rem);
  border: 1px solid var(--toolbox-border);
  border-radius: 0.78rem;
  background: color-mix(
    in srgb,
    var(--toolbox-surface-soft) 43%,
    var(--toolbox-surface)
  );
}

.rule-card {
  display: grid;
  gap: 0.45rem;
}

.rule-card p:not(.eyebrow) {
  color: var(--toolbox-muted);
  font-size: 0.84rem;
  white-space: pre-wrap;
}

.constraint-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.constraint-chips :where(li, span) {
  display: inline-flex;
  align-items: center;
  padding: 0.25rem 0.5rem;
  border: 1px solid
    color-mix(in srgb, var(--toolbox-accent) 24%, var(--toolbox-border));
  border-radius: 999px;
  background: var(--toolbox-accent-soft);
  color: var(--toolbox-accent);
  font-size: 0.7rem;
  font-weight: 720;
}

.option-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  padding-block: 0.35rem;
  color: var(--toolbox-text) !important;
  font-size: 0.8rem !important;
  font-weight: 610 !important;
  letter-spacing: 0 !important;
  cursor: pointer;
}

.option-row + .option-row {
  border-top: 1px solid
    color-mix(in srgb, var(--toolbox-border) 68%, transparent);
}

.section-heading {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.65rem 1rem;
}

.field-grid,
.inline-fields,
.helper-controls {
  display: grid;
  gap: 0.7rem;
}

.field-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.inline-fields {
  grid-template-columns: minmax(6rem, 0.7fr) minmax(7.5rem, 1fr);
  align-items: end;
}

.compact-field {
  width: min(100%, 9rem);
}

.button-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.45rem;
}

.panel-section {
  display: grid;
  gap: 0.72rem;
}

.panel-section.action-row {
  display: flex;
}

.feedback-callout,
.status-line,
.error-callout,
.callout {
  margin: 0;
  padding: 0.68rem 0.78rem;
  border: 1px solid var(--toolbox-border);
  border-radius: 0.62rem;
  background: var(--toolbox-surface-soft);
  color: var(--toolbox-text);
  font-size: 0.8rem;
  line-height: 1.48 !important;
}

.feedback-success {
  border-color: color-mix(
    in srgb,
    var(--sudoku-success) 34%,
    var(--toolbox-border)
  );
  background: color-mix(
    in srgb,
    var(--sudoku-success) 9%,
    var(--toolbox-surface)
  );
  color: var(--sudoku-success);
}

.feedback-error,
.error-callout {
  border-color: color-mix(
    in srgb,
    var(--toolbox-danger) 38%,
    var(--toolbox-border)
  );
  background: color-mix(
    in srgb,
    var(--toolbox-danger) 9%,
    var(--toolbox-surface)
  );
  color: var(--toolbox-danger);
}

.feedback-info,
.status-line {
  border-color: color-mix(
    in srgb,
    var(--sudoku-info) 30%,
    var(--toolbox-border)
  );
  background: color-mix(in srgb, var(--sudoku-info) 8%, var(--toolbox-surface));
  color: var(--sudoku-info);
}

.callout {
  border-color: color-mix(
    in srgb,
    var(--sudoku-warning) 30%,
    var(--toolbox-border)
  );
  background: color-mix(
    in srgb,
    var(--sudoku-warning) 8%,
    var(--toolbox-surface)
  );
  color: color-mix(in srgb, var(--sudoku-warning) 84%, var(--toolbox-text));
}

/* Sudoku board */

.sudoku-board-frame {
  --board-pad: clamp(0.28rem, 0.75vw, 0.48rem);
  --board-edge: clamp(2px, 0.35vw, 3px);
  position: relative;
  isolation: isolate;
  width: min(100%, 43rem);
  padding: var(--board-pad);
  border: 1px solid var(--toolbox-border);
  border-radius: var(--sudoku-board-radius);
  background: color-mix(
    in srgb,
    var(--toolbox-surface-soft) 74%,
    var(--toolbox-surface)
  );
  box-shadow:
    0 0.6rem 1.8rem rgb(20 30 60 / 9%),
    inset 0 1px 0 color-mix(in srgb, white 38%, transparent);
  container-type: inline-size;
  user-select: none;
  -webkit-user-select: none;
}

.sudoku-board {
  position: relative;
  width: 100%;
  display: grid;
  grid-template-columns: repeat(var(--sudoku-size), minmax(0, 1fr));
  grid-template-rows: repeat(var(--sudoku-size), minmax(0, 1fr));
  aspect-ratio: 1;
  overflow: hidden;
  border: var(--board-edge) solid var(--sudoku-line-strong);
  border-radius: clamp(0.22rem, 0.55vw, 0.42rem);
  background: var(--sudoku-line);
  box-shadow: 0 1px 0 color-mix(in srgb, white 22%, transparent);
  touch-action: none;
}

.sudoku-cell {
  --cell-fill: var(--toolbox-surface);
  position: relative;
  min-width: 0 !important;
  min-height: 0 !important;
  overflow: hidden;
  padding: 0 !important;
  border: 0.5px solid var(--sudoku-line) !important;
  border-radius: 0 !important;
  outline-offset: -3px !important;
  background: var(--cell-fill) !important;
  box-shadow: none !important;
  color: var(--toolbox-accent) !important;
  font-variant-numeric: tabular-nums;
  cursor: pointer;
  transition:
    background-color 100ms ease,
    color 100ms ease;
}

.sudoku-cell.is-given {
  color: var(--toolbox-text) !important;
  cursor: default;
}

.sudoku-cell[class*="has-color-"] {
  --cell-fill: color-mix(
    in srgb,
    var(--sudoku-mark-color) 24%,
    var(--toolbox-surface)
  );
}

.sudoku-cell.is-selected {
  background: color-mix(
    in srgb,
    var(--toolbox-accent) 20%,
    var(--cell-fill)
  ) !important;
}

.sudoku-cell.is-selected::after {
  position: absolute;
  z-index: 5;
  inset: max(1px, 5%);
  border: max(1.5px, 0.25cqi) solid
    color-mix(in srgb, var(--toolbox-accent) 82%, transparent);
  border-radius: max(1px, 0.25cqi);
  content: "";
  pointer-events: none;
}

.sudoku-cell.has-conflict {
  background: color-mix(
    in srgb,
    var(--toolbox-danger) 18%,
    var(--cell-fill)
  ) !important;
  color: var(--toolbox-danger) !important;
}

.sudoku-cell.has-conflict::before {
  position: absolute;
  z-index: 4;
  inset: 10%;
  border-radius: 50%;
  background: color-mix(in srgb, var(--toolbox-danger) 10%, transparent);
  content: "";
  pointer-events: none;
}

.sudoku-cell:focus-visible {
  outline: none !important;
}

.sudoku-cell:focus-visible::after {
  position: absolute;
  z-index: 6;
  inset: max(1px, 4%);
  border: max(2px, 0.3cqi) solid var(--toolbox-focus);
  border-radius: max(1px, 0.25cqi);
  content: "";
  pointer-events: none;
}

@media (hover: hover) {
  .sudoku-cell:not(.is-selected):not(.has-conflict):hover {
    background: color-mix(
      in srgb,
      var(--toolbox-accent) 8%,
      var(--cell-fill)
    ) !important;
  }
}

.cell-value,
.corner-marks,
.center-marks {
  position: relative;
  z-index: 4;
  pointer-events: none;
}

.cell-value {
  display: block;
  font-size: clamp(0.74rem, 4.2cqi, 2rem);
  font-weight: 650;
  line-height: 1;
}

.is-given .cell-value {
  font-weight: 820;
}

.corner-marks {
  position: absolute;
  inset: 7%;
  display: flex;
  align-content: flex-start;
  align-items: flex-start;
  flex-wrap: wrap;
  justify-content: flex-start;
  gap: 0 0.14em;
  overflow: hidden;
  color: color-mix(in srgb, var(--toolbox-text) 77%, var(--toolbox-muted));
  font-size: clamp(0.34rem, 1.38cqi, 0.64rem);
  font-weight: 720;
  line-height: 1.05;
  text-align: left;
}

.center-marks {
  max-width: 88%;
  display: block;
  overflow: hidden;
  color: color-mix(in srgb, var(--toolbox-text) 72%, var(--toolbox-muted));
  font-size: clamp(0.38rem, 1.48cqi, 0.68rem);
  font-weight: 650;
  letter-spacing: 0.035em;
  line-height: 1.08;
  overflow-wrap: anywhere;
}

.constraint-layer {
  position: absolute;
  z-index: 3;
  top: var(--board-pad);
  left: var(--board-pad);
  width: calc(100% - var(--board-pad) - var(--board-pad));
  height: calc(100% - var(--board-pad) - var(--board-pad));
  overflow: visible;
  pointer-events: none;
  shape-rendering: geometricPrecision;
}

.constraint-layer :where(path, polyline, line, circle) {
  vector-effect: non-scaling-stroke;
}

.region-boundaries path {
  fill: none;
  stroke: var(--sudoku-line-strong);
  stroke-linecap: square;
  stroke-linejoin: miter;
  stroke-width: clamp(1.8px, 0.28cqi, 3px);
}

.constraint-diagonal {
  stroke: color-mix(in srgb, var(--toolbox-accent) 68%, var(--toolbox-text));
  stroke-linecap: round;
  stroke-width: clamp(2px, 0.34cqi, 3.5px);
  opacity: 0.66;
}

.constraint-cage path {
  fill: none;
  stroke: color-mix(in srgb, var(--toolbox-text) 76%, var(--toolbox-muted));
  stroke-dasharray: 3 2.5;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: clamp(1px, 0.17cqi, 1.7px);
}

.constraint-cage text {
  fill: var(--toolbox-text);
  font-family: var(--toolbox-font);
  font-size: 0.22px;
  font-weight: 760;
  paint-order: stroke;
  stroke: var(--toolbox-surface);
  stroke-width: 0.035px;
}

.constraint-thermo polyline {
  fill: none;
  stroke: color-mix(in srgb, var(--toolbox-muted) 48%, var(--toolbox-surface));
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: clamp(8px, 2.05cqi, 17px);
}

.constraint-thermo circle {
  fill: color-mix(in srgb, var(--toolbox-muted) 42%, var(--toolbox-surface));
  stroke: color-mix(in srgb, var(--toolbox-muted) 67%, var(--toolbox-surface));
  stroke-width: clamp(1px, 0.15cqi, 1.5px);
}

.constraint-arrow polyline {
  fill: none;
  stroke: color-mix(in srgb, var(--toolbox-text) 62%, var(--toolbox-muted));
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: clamp(2px, 0.34cqi, 3px);
}

.constraint-arrow circle:first-child {
  fill: color-mix(in srgb, var(--toolbox-surface) 78%, transparent);
  stroke: color-mix(in srgb, var(--toolbox-text) 62%, var(--toolbox-muted));
  stroke-width: clamp(1.5px, 0.27cqi, 2.5px);
}

.constraint-arrow circle:last-child {
  fill: color-mix(in srgb, var(--toolbox-text) 66%, var(--toolbox-muted));
  stroke: none;
}

.constraint-renban polyline,
.constraint-palindrome polyline {
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: clamp(8px, 2.1cqi, 18px);
}

.constraint-renban polyline {
  stroke: color-mix(in srgb, #d973b4 44%, transparent);
}

.constraint-palindrome polyline {
  stroke: color-mix(in srgb, #8f9aae 48%, transparent);
}

.constraint-palindrome circle {
  fill: color-mix(in srgb, var(--toolbox-surface) 82%, transparent);
  stroke: color-mix(in srgb, #657087 65%, var(--toolbox-muted));
  stroke-width: clamp(1px, 0.15cqi, 1.5px);
}

.constraint-kropki {
  stroke: color-mix(in srgb, var(--toolbox-text) 80%, var(--toolbox-muted));
  stroke-width: clamp(1.2px, 0.2cqi, 2px);
}

.constraint-kropki--white {
  fill: var(--toolbox-surface);
}

.constraint-kropki--black {
  fill: color-mix(in srgb, var(--toolbox-text) 88%, black);
}

.constraint-label {
  dominant-baseline: central;
  fill: var(--toolbox-text);
  font-family: var(--toolbox-font);
  font-size: 0.28px;
  font-weight: 850;
  paint-order: stroke;
  stroke: var(--toolbox-surface);
  stroke-linejoin: round;
  stroke-width: 0.07px;
  text-anchor: middle;
}

.constraint-label--inequality {
  font-size: 0.38px;
}

/* Number and colour entry */

.number-pad {
  display: grid;
  gap: 0.65rem;
}

.mode-switcher {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.mode-switcher button {
  padding-inline: 0.35rem;
  font-size: 0.72rem;
}

.digit-pad {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(2.75rem, 1fr));
  gap: 0.42rem;
}

.digit-pad--wide {
  grid-template-columns: repeat(auto-fit, minmax(2.5rem, 1fr));
}

.digit-pad button {
  min-width: 0;
  min-height: 2.9rem;
  padding-inline: 0.35rem;
  font-size: 1rem;
  font-variant-numeric: tabular-nums;
}

.digit-pad .erase-key {
  padding-inline: 0.65rem;
  color: var(--toolbox-muted);
  font-size: 0.76rem;
}

.color-choice > span:first-child {
  width: 1.35rem;
  height: 1.35rem;
  display: block;
  border: 2px solid color-mix(in srgb, var(--sudoku-mark-color) 75%, white);
  border-radius: 50%;
  background: var(--sudoku-mark-color);
  box-shadow:
    0 0 0 1px color-mix(in srgb, var(--sudoku-mark-color) 72%, black),
    inset 0 0.18rem 0.28rem rgb(255 255 255 / 22%);
}

.color-1,
.has-color-1 {
  --sudoku-mark-color: #e56f65;
}

.color-2,
.has-color-2 {
  --sudoku-mark-color: #eca73f;
}

.color-3,
.has-color-3 {
  --sudoku-mark-color: #e0c84f;
}

.color-4,
.has-color-4 {
  --sudoku-mark-color: #62b77a;
}

.color-5,
.has-color-5 {
  --sudoku-mark-color: #4bb8b4;
}

.color-6,
.has-color-6 {
  --sudoku-mark-color: #5d93dd;
}

.color-7,
.has-color-7 {
  --sudoku-mark-color: #9a7cda;
}

.color-8,
.has-color-8 {
  --sudoku-mark-color: #ce78b0;
}

/* Setter, solver, and helper result surfaces */

.constraint-list,
.library-list,
.cell-possibilities {
  margin: 0;
  padding: 0;
  list-style: none;
}

.constraint-list {
  display: grid;
  gap: 0.35rem;
}

.constraint-list li {
  min-width: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.55rem;
  padding: 0.38rem 0.45rem 0.38rem 0.65rem;
  border: 1px solid var(--toolbox-border);
  border-radius: 0.58rem;
  background: var(--toolbox-surface);
  color: var(--toolbox-text);
  font-size: 0.78rem;
}

.constraint-list li > span {
  min-width: 0;
  overflow-wrap: anywhere;
}

.subtabs {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.helper-controls {
  grid-template-columns: repeat(3, minmax(0, 1fr));
  align-items: end;
}

.helper-controls .check-row {
  align-self: center;
}

.helper-result {
  display: grid;
  gap: 0.8rem;
  margin-top: 0.9rem;
}

.metric-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(8rem, 1fr));
  gap: 0.45rem;
}

.metric-row > span {
  min-width: 0;
  padding: 0.55rem 0.65rem;
  border: 1px solid var(--toolbox-border);
  border-radius: 0.58rem;
  background: var(--toolbox-surface);
  color: var(--toolbox-muted);
  font-size: 0.75rem;
  line-height: 1.35;
}

.metric-row strong {
  color: var(--toolbox-text);
  font-size: 0.9rem;
}

.cell-possibilities {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(9rem, 1fr));
  gap: 0.35rem;
  counter-reset: none;
}

.cell-possibilities li {
  padding: 0.42rem 0.55rem;
  border-radius: 0.48rem;
  background: var(--toolbox-surface-soft);
  color: var(--toolbox-text);
  font-family:
    ui-monospace, SFMono-Regular, Consolas, "Liberation Mono", monospace;
  font-size: 0.72rem;
}

.combination-cloud,
.pair-table {
  max-height: 17rem;
  display: flex;
  align-content: flex-start;
  flex-wrap: wrap;
  gap: 0.35rem;
  overflow: auto;
  padding: 0.65rem;
  border: 1px solid var(--toolbox-border);
  border-radius: 0.62rem;
  background: color-mix(
    in srgb,
    var(--toolbox-background) 52%,
    var(--toolbox-surface)
  );
  scrollbar-color: var(--toolbox-border) transparent;
}

.combination-cloud code,
.pair-table code {
  padding: 0.28rem 0.44rem;
  border: 1px solid
    color-mix(in srgb, var(--toolbox-accent) 18%, var(--toolbox-border));
  border-radius: 0.42rem;
  background: var(--toolbox-surface);
  color: var(--toolbox-accent);
  font-family:
    ui-monospace, SFMono-Regular, Consolas, "Liberation Mono", monospace;
  font-size: 0.72rem;
  font-weight: 720;
}

.residual-equation {
  color: var(--toolbox-muted);
  font-family:
    ui-monospace, SFMono-Regular, Consolas, "Liberation Mono", monospace;
  font-size: clamp(1.15rem, 3vw, 1.65rem);
  letter-spacing: -0.035em;
  text-align: center;
}

.residual-equation strong {
  color: var(--toolbox-accent);
}

.analysis-summary,
.logical-results {
  display: grid;
  gap: 0.8rem;
}

.status-pill {
  display: inline-flex;
  align-items: center;
  align-self: flex-start;
  padding: 0.28rem 0.55rem;
  border: 1px solid var(--toolbox-border);
  border-radius: 999px;
  background: var(--toolbox-surface);
  color: var(--toolbox-muted);
  font-size: 0.67rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.status-solved {
  border-color: color-mix(
    in srgb,
    var(--sudoku-success) 35%,
    var(--toolbox-border)
  );
  background: color-mix(
    in srgb,
    var(--sudoku-success) 9%,
    var(--toolbox-surface)
  );
  color: var(--sudoku-success);
}

.status-invalid {
  border-color: color-mix(
    in srgb,
    var(--toolbox-danger) 38%,
    var(--toolbox-border)
  );
  background: color-mix(
    in srgb,
    var(--toolbox-danger) 9%,
    var(--toolbox-surface)
  );
  color: var(--toolbox-danger);
}

.status-stuck,
.status-limit,
.status-step-limit {
  border-color: color-mix(
    in srgb,
    var(--sudoku-warning) 36%,
    var(--toolbox-border)
  );
  background: color-mix(
    in srgb,
    var(--sudoku-warning) 8%,
    var(--toolbox-surface)
  );
  color: var(--sudoku-warning);
}

.solve-steps {
  max-height: 32rem;
  display: grid;
  gap: 0.42rem;
  overflow: auto;
  padding: 0.15rem;
  scrollbar-color: var(--toolbox-border) transparent;
}

.solve-step {
  width: 100%;
  min-height: 0 !important;
  display: grid !important;
  grid-template-columns: 2rem minmax(0, 1fr);
  align-items: start !important;
  gap: 0.65rem !important;
  padding: 0.68rem !important;
  text-align: left !important;
}

.solve-step > span:last-child {
  min-width: 0;
  display: grid;
  gap: 0.18rem;
}

.solve-step small,
.step-effects {
  display: block;
  color: var(--toolbox-muted);
  font-size: 0.72rem;
  font-weight: 500;
  line-height: 1.45;
  overflow-wrap: anywhere;
}

.step-number {
  width: 2rem;
  height: 2rem;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--toolbox-surface-soft);
  color: var(--toolbox-muted);
  font-size: 0.72rem;
  font-variant-numeric: tabular-nums;
  font-weight: 800;
}

.solve-step.is-active .step-number {
  background: var(--toolbox-accent-contrast);
  color: var(--toolbox-accent);
}

.solve-step.is-active :where(strong, small, .step-effects) {
  color: var(--toolbox-accent-contrast);
}

.shortcut-note {
  padding-top: 0.65rem;
  border-top: 1px solid var(--toolbox-border);
  font-size: 0.72rem;
}

/* Dialogs and local library */

.modal {
  width: min(calc(100% - 2rem), 40rem);
  max-width: none;
  max-height: min(calc(100dvh - 2rem), 52rem);
  margin: auto;
  padding: 0;
  overflow: hidden;
  border: 1px solid var(--toolbox-border);
  border-radius: 0.95rem;
  outline: none;
  background: var(--toolbox-surface);
  box-shadow: 0 1.3rem 4.5rem rgb(5 10 25 / 28%);
  color: var(--toolbox-text);
}

.modal--wide {
  width: min(calc(100% - 2rem), 68rem);
}

.modal::backdrop {
  background: rgb(8 13 28 / 58%);
  backdrop-filter: blur(4px);
}

.modal[open] {
  animation: modal-enter 150ms ease-out both;
}

@keyframes modal-enter {
  from {
    opacity: 0;
    transform: translateY(0.45rem) scale(0.985);
  }

  to {
    opacity: 1;
    transform: none;
  }
}

.modal__surface {
  max-height: inherit;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr);
}

.modal__header {
  min-height: 4rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 1rem 0.85rem 1.2rem;
  border-bottom: 1px solid var(--toolbox-border);
  background: color-mix(
    in srgb,
    var(--toolbox-surface) 90%,
    var(--toolbox-background)
  );
}

.modal__header .icon-button {
  width: 2.45rem;
  min-width: 2.45rem;
  height: 2.45rem;
  min-height: 2.45rem;
  padding: 0;
  border-radius: 50%;
  font-size: 1.35rem;
  font-weight: 450;
}

.modal__body {
  min-height: 0;
  overflow: auto;
  overscroll-behavior: contain;
  padding: clamp(0.9rem, 2.2vw, 1.3rem);
  scrollbar-color: var(--toolbox-border) transparent;
}

.import-export-grid,
.help-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

.import-export-grid > section,
.help-grid > section {
  min-width: 0;
  padding: 0.9rem;
  border: 1px solid var(--toolbox-border);
  border-radius: 0.75rem;
  background: color-mix(
    in srgb,
    var(--toolbox-surface-soft) 46%,
    var(--toolbox-surface)
  );
}

.import-export-grid textarea {
  font-family:
    ui-monospace, SFMono-Regular, Consolas, "Liberation Mono", monospace;
  font-size: 0.76rem;
  line-height: 1.5;
}

.export-actions {
  align-items: stretch;
}

.export-actions button {
  flex: 1 1 11rem;
}

.library-toolbar {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.8rem 1.25rem;
  margin-bottom: 1rem;
}

.library-list {
  display: grid;
  gap: 0.45rem;
}

.library-list li {
  min-width: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 0.5rem;
  padding: 0.38rem;
  border: 1px solid var(--toolbox-border);
  border-radius: 0.68rem;
  background: var(--toolbox-surface);
}

.library-open {
  min-width: 0;
  display: grid !important;
  justify-items: start !important;
  gap: 0.18rem !important;
  border-color: transparent !important;
  background: transparent !important;
  box-shadow: none !important;
  text-align: left !important;
}

.library-open strong {
  max-width: 100%;
  overflow: hidden;
  color: var(--toolbox-text);
  text-overflow: ellipsis;
  white-space: nowrap;
}

.library-open span {
  color: var(--toolbox-muted);
  font-size: 0.7rem;
  font-weight: 520;
}

.empty-state {
  display: grid;
  justify-items: center;
  gap: 0.4rem;
  padding: clamp(2rem, 8vw, 4.5rem) 1rem;
  border: 1px dashed var(--toolbox-border);
  border-radius: 0.8rem;
  background: var(--toolbox-surface-soft);
  color: var(--toolbox-muted);
  text-align: center;
}

.empty-state::before {
  width: 3rem;
  height: 3rem;
  display: grid;
  place-items: center;
  margin-bottom: 0.25rem;
  border: 1px solid var(--toolbox-border);
  border-radius: 0.8rem;
  background: var(--toolbox-surface);
  color: var(--toolbox-accent);
  content: "▦";
  font-size: 1.35rem;
}

.danger-zone {
  display: flex;
  justify-content: flex-end;
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--toolbox-border);
}

.help-grid section {
  display: grid;
  align-content: start;
  gap: 0.55rem;
}

.help-grid p {
  color: var(--toolbox-muted);
  font-size: 0.84rem;
}

.help-grid p strong {
  color: var(--toolbox-text);
}

.shortcut-list {
  display: grid;
  gap: 0.28rem;
}

.shortcut-list > div {
  display: grid;
  grid-template-columns: minmax(7rem, 0.62fr) minmax(0, 1fr);
  gap: 0.65rem;
  padding-block: 0.3rem;
  border-bottom: 1px solid
    color-mix(in srgb, var(--toolbox-border) 66%, transparent);
  font-size: 0.76rem;
}

.shortcut-list dt {
  color: var(--toolbox-text);
  font-weight: 720;
}

.shortcut-list dd {
  margin: 0;
  color: var(--toolbox-muted);
}

/* Loading and fatal recovery */

.workbench-loading {
  min-height: min(34rem, calc(100dvh - 10rem));
  display: grid;
  grid-auto-flow: column;
  justify-content: center;
  place-items: center;
  margin: 0;
  color: var(--toolbox-muted);
  font-size: 0.88rem;
}

.workbench-loading::before {
  width: 1.15rem;
  height: 1.15rem;
  margin-right: 0.65rem;
  border: 2px solid var(--toolbox-border);
  border-top-color: var(--toolbox-accent);
  border-radius: 50%;
  content: "";
  animation: loading-spin 700ms linear infinite;
}

@keyframes loading-spin {
  to {
    transform: rotate(1turn);
  }
}

.fatal-error {
  width: min(calc(100% - 2rem), 36rem);
  display: grid;
  gap: 1rem;
  margin: clamp(2rem, 10vh, 7rem) auto;
  padding: clamp(1.2rem, 4vw, 2rem);
  border: 1px solid var(--toolbox-border);
  border-radius: 1rem;
  background: var(--toolbox-surface);
  box-shadow: var(--toolbox-shadow);
}

.fatal-error p {
  color: var(--toolbox-muted);
}

.fatal-error button {
  justify-self: start;
}

/* Responsive composition */

@media (max-width: 67rem) {
  .workbench-grid,
  .workbench-grid--helpers {
    grid-template-columns: minmax(0, 1fr);
  }

  .side-panel {
    width: 100%;
  }

  .board-toolbar,
  .board-meta {
    width: min(100%, 45rem);
    margin-inline: auto;
  }

  .helper-controls {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 48rem) {
  .toolbox-shell__main {
    padding-inline: 0.75rem;
  }

  .workbench-hero {
    align-items: flex-start;
    flex-direction: column;
  }

  .workbench-hero::after {
    opacity: 0.58;
  }

  .hero-actions {
    justify-content: flex-start;
  }

  .workbench-status,
  .board-toolbar {
    align-items: flex-start;
    flex-direction: column;
  }

  .board-toolbar > :where(.toolbar-group, .action-row) {
    width: 100%;
  }

  .side-panel {
    padding: 0.75rem;
  }

  .subtabs,
  .import-export-grid,
  .help-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .library-toolbar {
    flex-direction: column;
  }
}

@media (max-width: 38rem) {
  .workspace-tabs {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .field-grid,
  .helper-controls {
    grid-template-columns: minmax(0, 1fr);
  }

  .section-heading {
    align-items: stretch;
    flex-direction: column;
  }

  .compact-field {
    width: 100%;
  }

  .panel-section.action-row,
  .action-row,
  .hero-actions {
    align-items: stretch;
  }

  .panel-section.action-row > button,
  .action-row > button,
  .hero-actions > button {
    flex: 1 1 9rem;
  }

  .modal {
    width: calc(100% - 1rem);
    max-height: calc(100dvh - 1rem);
    border-radius: 0.78rem;
  }

  .modal__header {
    min-height: 3.6rem;
    padding-left: 0.9rem;
  }

  .modal__body {
    padding: 0.75rem;
  }

  .library-list li {
    grid-template-columns: minmax(0, 1fr);
  }

  .library-list li > .text-button {
    justify-self: end;
  }
}

@media (max-width: 30rem) {
  .toolbox-shell__main {
    padding: 0.55rem;
  }

  .sudoku-workbench {
    gap: 0.65rem;
  }

  .workbench-hero,
  .side-panel {
    border-radius: 0.72rem;
  }

  .workbench-hero {
    padding: 0.9rem;
  }

  .workspace-tabs button {
    min-height: 2.7rem;
  }

  .board-surface {
    padding: 0.25rem;
  }

  .sudoku-board-frame {
    --board-pad: 0.2rem;
    border-radius: 0.55rem;
  }

  .mode-switcher {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .inline-fields {
    grid-template-columns: minmax(0, 1fr);
  }

  .button-grid {
    gap: 0.35rem;
  }

  .button-grid button {
    padding-inline: 0.4rem;
    font-size: 0.75rem;
  }

  .shortcut-list > div {
    grid-template-columns: minmax(0, 1fr);
    gap: 0.12rem;
  }
}

@media (pointer: coarse) {
  :where(.sudoku-workbench, .modal, .fatal-error) button:not(.sudoku-cell),
  :where(.sudoku-workbench, .modal)
    :where(input:not([type="checkbox"]):not([type="radio"]), select) {
    min-height: 2.75rem;
  }

  .sudoku-cell {
    -webkit-tap-highlight-color: transparent;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

@media (forced-colors: active) {
  .sudoku-cell.is-selected::after,
  .sudoku-cell.has-conflict::before {
    border: 2px solid Highlight;
    background: transparent;
  }

  .sudoku-cell.has-conflict {
    outline: 2px dashed Mark;
    outline-offset: -4px;
  }

  .constraint-layer :where(path, polyline, line, circle),
  .region-boundaries path {
    stroke: CanvasText;
  }
}

/* A print is a clean puzzle sheet, not a snapshot of the controls. */

@media print {
  @page {
    size: auto;
    margin: 1.2cm;
  }

  :root,
  body {
    background: #fff !important;
    color: #000 !important;
  }

  .toolbox-shell {
    min-height: 0;
    background: #fff !important;
    color: #000 !important;
  }

  .toolbox-shell__header,
  .toolbox-shell__footer,
  .hero-actions,
  .workspace-tabs,
  .workbench-status,
  .board-toolbar,
  .side-panel,
  .number-pad,
  .paused-cover,
  .feedback-callout,
  .status-line,
  .modal {
    display: none !important;
  }

  .toolbox-shell__main,
  .sudoku-workbench,
  .workbench-grid,
  .board-column {
    width: 100% !important;
    max-width: none !important;
    display: block !important;
    margin: 0 !important;
    padding: 0 !important;
  }

  .workbench-hero {
    margin-bottom: 0.6cm;
    padding: 0 !important;
    border: 0 !important;
    background: transparent !important;
    box-shadow: none !important;
  }

  .workbench-hero::after {
    display: none;
  }

  .hero-copy > p:not(.eyebrow) {
    color: #333 !important;
  }

  .board-surface {
    display: block;
    padding: 0 !important;
    border: 0 !important;
    background: #fff !important;
    box-shadow: none !important;
  }

  .sudoku-board-frame {
    --toolbox-surface: #fff;
    --toolbox-text: #000;
    --toolbox-muted: #444;
    --toolbox-accent: #111;
    --toolbox-danger: #000;
    --sudoku-line: #888;
    --sudoku-line-strong: #000;
    width: min(100%, 18cm);
    margin-inline: auto;
    padding: 0;
    border: 0;
    background: #fff !important;
    box-shadow: none;
    break-inside: avoid;
    print-color-adjust: exact;
  }

  .sudoku-cell,
  .sudoku-cell.is-selected,
  .sudoku-cell.has-conflict,
  .sudoku-cell[class*="has-color-"] {
    --cell-fill: #fff;
    background: #fff !important;
    color: #000 !important;
  }

  .sudoku-cell::before,
  .sudoku-cell::after {
    display: none !important;
  }

  .constraint-layer {
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
  }

  .board-meta,
  .rule-card {
    width: min(100%, 18cm);
    margin: 0.5cm auto 0;
    color: #222 !important;
  }

  .rule-card {
    padding: 0;
    border: 0;
    background: transparent !important;
  }
}