:root {
  color-scheme: light;
  --viewport-height: 100dvh;
  --bg: #f6f1e8;
  --surface: rgba(255, 252, 247, 0.86);
  --surface-strong: rgba(255, 255, 255, 0.96);
  --surface-soft: rgba(255, 255, 255, 0.78);
  --surface-border: rgba(56, 78, 86, 0.12);
  --text: #17303a;
  --text-soft: #5b6c73;
  --text-muted: #72848a;
  --x-color: #d25f4d;
  --o-color: #2c7a78;
  --success: #2a7d56;
  --warning: #c97d2b;
  --shadow: 0 18px 42px rgba(39, 61, 69, 0.08);
  --radius-xl: 28px;
  --radius-lg: 20px;
  --radius-md: 16px;
  --radius-sm: 12px;
  --board-max: min(62vmin, calc(var(--viewport-height) - 290px), 430px);
  --transition-fast: 180ms ease;
  --transition-smooth: 260ms cubic-bezier(0.22, 1, 0.36, 1);
  --screen-transition: 460ms cubic-bezier(0.2, 0.85, 0.2, 1);
  --line-x: 50%;
  --line-y: 50%;
  --line-length: 0px;
  --line-angle: 0deg;
}

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

html,
body {
  height: 100%;
  overflow: hidden;
}

html {
  overscroll-behavior: none;
  scroll-behavior: auto;
}

body {
  margin: 0;
  min-height: 100%;
  font-family: "Avenir Next", "Segoe UI Variable", "Segoe UI", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(210, 95, 77, 0.12), transparent 32%),
    radial-gradient(circle at top right, rgba(44, 122, 120, 0.16), transparent 30%),
    linear-gradient(180deg, #fbf7ef 0%, var(--bg) 55%, #efe8dc 100%);
  overscroll-behavior: none;
}

.background-layer {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  overflow: hidden;
}

.background-pattern-motion,
.background-pattern {
  position: absolute;
  inset: -48px;
}

.background-pattern-motion {
  animation: pattern-drift 44s linear infinite alternate;
  will-change: transform;
}

.background-pattern {
  background-image: url("../img/xo-pattern.svg");
  background-repeat: repeat;
  background-size: 152px 152px;
  opacity: 0.06;
  transform: translate3d(0, 0, 0);
  will-change: transform;
}

.background-glow {
  position: absolute;
  border-radius: 50%;
  filter: blur(14px);
  opacity: 0.45;
}

.background-glow--warm {
  top: 8%;
  left: 7%;
  width: 26rem;
  height: 26rem;
  background: radial-gradient(circle, rgba(210, 95, 77, 0.1) 0%, rgba(210, 95, 77, 0.03) 46%, transparent 72%);
}

.background-glow--cool {
  right: 6%;
  bottom: 7%;
  width: 30rem;
  height: 30rem;
  background: radial-gradient(circle, rgba(44, 122, 120, 0.12) 0%, rgba(44, 122, 120, 0.03) 48%, transparent 74%);
}

body::before,
body::after {
  content: "";
  position: fixed;
  pointer-events: none;
  z-index: 0;
  filter: blur(18px);
  opacity: 0.65;
}

body::before {
  inset: 0;
  background:
    radial-gradient(circle at 20% 15%, rgba(255, 255, 255, 0.28), transparent 28%),
    radial-gradient(circle at 78% 82%, rgba(255, 255, 255, 0.2), transparent 32%);
  opacity: 0.82;
}

body::after {
  inset: 0;
  background: radial-gradient(circle at center, transparent 55%, rgba(23, 48, 58, 0.05) 100%);
  opacity: 0.88;
}

h1,
h2,
h3 {
  margin: 0;
  font-family: "Gill Sans", "Avenir Next", "Segoe UI Variable", sans-serif;
  line-height: 1.02;
}

h1 {
  font-size: clamp(2rem, 4.6vw, 3.4rem);
  letter-spacing: -0.04em;
}

.site-viewport {
  position: relative;
  z-index: 1;
  height: var(--viewport-height);
  overflow: hidden;
}

.screen-track {
  height: 200%;
  transform: translate3d(0, 0, 0);
  transition: transform var(--screen-transition);
  will-change: transform;
}

.screen-track[data-screen="1"] {
  transform: translate3d(0, -50%, 0);
}

.screen {
  height: var(--viewport-height);
  padding: clamp(12px, 2vw, 20px);
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-card,
.seo-block {
  position: relative;
  width: min(1120px, 100%);
  border: 1px solid var(--surface-border);
  background: var(--surface);
  backdrop-filter: blur(14px);
  box-shadow:
    var(--shadow),
    inset 0 1px 0 rgba(255, 255, 255, 0.45);
  overflow: hidden;
}

.hero-card::before,
.seo-block::before {
  content: "";
  position: absolute;
  inset: 1px;
  border-radius: inherit;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.5), rgba(255, 255, 255, 0.1) 28%, transparent 56%),
    radial-gradient(circle at top left, rgba(255, 255, 255, 0.22), transparent 28%);
  pointer-events: none;
  opacity: 0.8;
}

.game-screen-card > *,
.content-screen-card > * {
  position: relative;
  z-index: 1;
}

.game-screen-card,
.content-screen-card {
  height: 100%;
  min-height: 0;
  border-radius: var(--radius-xl);
}

.game-screen-card {
  padding: clamp(14px, 2vw, 22px);
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  gap: clamp(10px, 1.5vw, 14px);
}

.content-screen-card {
  padding: clamp(16px, 2vw, 24px);
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  gap: 14px;
}

.hero-copy {
  max-width: 42rem;
  display: grid;
  gap: 6px;
}

.page-menu {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
}

.page-menu a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 38px;
  padding: 8px 13px;
  border-radius: 999px;
  border: 1px solid rgba(23, 48, 58, 0.14);
  background: rgba(255, 255, 255, 0.86);
  color: var(--text);
  font-size: 0.84rem;
  font-weight: 700;
  text-decoration: none;
  box-shadow: 0 8px 18px rgba(23, 48, 58, 0.05);
  transition:
    transform var(--transition-fast),
    color var(--transition-fast),
    background var(--transition-fast),
    box-shadow var(--transition-fast);
}

.page-menu a:hover,
.page-menu a:focus-visible {
  transform: translateY(-1px);
  color: var(--text);
  background: rgba(255, 255, 255, 0.98);
  box-shadow: 0 12px 24px rgba(23, 48, 58, 0.08);
}

.page-menu--compact {
  margin-top: 8px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0;
  width: fit-content;
  padding: 6px 10px;
  border-radius: 999px;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-soft);
  background: rgba(255, 255, 255, 0.72);
}

.eyebrow::before {
  content: "";
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--x-color), var(--o-color));
}

.eyebrow-link {
  text-decoration: none;
  transition:
    color var(--transition-fast),
    background var(--transition-fast),
    transform var(--transition-fast);
}

.eyebrow-link:hover {
  color: var(--text);
  background: rgba(255, 255, 255, 0.9);
  transform: translateY(-1px);
}

.eyebrow-link:focus-visible {
  outline: 3px solid rgba(44, 122, 120, 0.32);
  outline-offset: 3px;
}

.subtitle,
.content-lead {
  margin: 0;
  color: var(--text-soft);
}

.subtitle {
  font-size: clamp(0.94rem, 1.7vw, 1.05rem);
  line-height: 1.45;
}

.content-lead {
  font-size: 0.98rem;
  line-height: 1.55;
}

.game-panel {
  min-height: 0;
  display: grid;
  grid-template-columns: minmax(0, 290px) minmax(0, 1fr);
  gap: 14px;
  align-items: stretch;
}

.game-panel[data-mode="bot"] {
  --board-max: min(56vmin, calc(var(--viewport-height) - 340px), 390px);
}

.game-panel[data-mode="bot"] .toolbar {
  gap: 10px;
}

.game-panel[data-mode="bot"] .control-group,
.game-panel[data-mode="bot"] .bot-settings {
  gap: 8px;
}

.game-panel[data-mode="bot"] .group-heading p {
  font-size: 0.8rem;
  line-height: 1.28;
}

.game-panel[data-mode="bot"] .chip-button {
  min-height: 38px;
  padding: 8px 12px;
}

.game-panel[data-mode="bot"] .bot-settings {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  align-items: start;
}

.game-panel[data-mode="bot"] .bot-settings .group-heading p {
  display: none;
}

.game-panel[data-mode="bot"] .group-heading {
  justify-items: center;
  text-align: center;
}

#modeSelector,
#starterSelector {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

#modeSelector .chip-button,
#starterSelector .chip-button {
  display: inline-flex;
  align-items: center;
  width: 100%;
  min-height: 40px;
  padding: 7px 12px;
  border-radius: 15px;
  font-size: 0.9rem;
  font-weight: 650;
  letter-spacing: -0.01em;
  justify-content: center;
  border: 1px solid rgba(23, 48, 58, 0.08);
  background: rgba(23, 48, 58, 0.04);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.5);
}

#modeSelector .chip-button:hover,
#starterSelector .chip-button:hover {
  background: rgba(23, 48, 58, 0.08);
}

#modeSelector .chip-button.is-active,
#starterSelector .chip-button.is-active {
  background: linear-gradient(135deg, #1d4954, #275f60);
  box-shadow:
    0 8px 18px rgba(39, 95, 96, 0.14),
    inset 0 1px 0 rgba(255, 255, 255, 0.14);
}

#difficultySelector {
  display: grid;
  gap: 8px;
}

#difficultySelector .chip-button {
  display: inline-flex;
  align-items: center;
  min-height: 38px;
  padding: 7px 12px;
  border-radius: 15px;
  font-size: 0.9rem;
  font-weight: 650;
  border: 1px solid rgba(23, 48, 58, 0.08);
  background: rgba(23, 48, 58, 0.04);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.5);
}

#difficultySelector .chip-button:hover {
  background: rgba(23, 48, 58, 0.08);
}

#difficultySelector .chip-button.is-active {
  color: #f7faf9;
  background: linear-gradient(135deg, #1d4954, #275f60);
  box-shadow:
    0 8px 18px rgba(39, 95, 96, 0.14),
    inset 0 1px 0 rgba(255, 255, 255, 0.14);
}

.game-panel[data-mode="bot"] #modeSelector,
.game-panel[data-mode="bot"] #sizeSelector,
.game-panel[data-mode="bot"] #starterSelector {
  justify-content: center;
}

.game-panel[data-mode="bot"] #difficultySelector,
.game-panel[data-mode="bot"] #starterSelector {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
}

.game-panel[data-mode="bot"] #difficultySelector .chip-button,
.game-panel[data-mode="bot"] #starterSelector .chip-button {
  width: 100%;
  justify-content: center;
}

.game-panel[data-mode="bot"] #difficultySelector {
  grid-template-columns: 1fr;
}

.toolbar,
.board-panel,
.content-card,
.faq-item {
  padding: 14px;
  border-radius: var(--radius-lg);
  background: var(--surface-strong);
  border: 1px solid rgba(56, 78, 86, 0.08);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.42);
}

.toolbar {
  display: grid;
  gap: 12px;
  align-content: start;
}

.control-group,
.bot-settings {
  display: grid;
  gap: 10px;
}

.bot-settings[hidden] {
  display: none;
}

.group-heading {
  display: grid;
  gap: 4px;
}

.group-heading h2 {
  font-size: 0.98rem;
  letter-spacing: -0.02em;
}

.group-heading p {
  margin: 0;
  font-size: 0.85rem;
  line-height: 1.36;
  color: var(--text-muted);
}

.chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.chip-button {
  border: 0;
  border-radius: 999px;
  padding: 10px 14px;
  min-height: 42px;
  font: inherit;
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--text);
  background: rgba(23, 48, 58, 0.06);
  cursor: pointer;
  transition:
    transform var(--transition-fast),
    background var(--transition-fast),
    color var(--transition-fast),
    box-shadow var(--transition-fast);
}

.chip-button:hover {
  transform: translateY(-1px);
  background: rgba(23, 48, 58, 0.1);
}

.chip-button:active {
  transform: scale(0.98);
}

.chip-button.is-active {
  color: #f7faf9;
  background: linear-gradient(135deg, #1d4954, #275f60);
  box-shadow: 0 10px 24px rgba(39, 95, 96, 0.18);
}

.board-panel {
  min-height: 0;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  gap: 12px;
  justify-items: center;
}

.board-status-wrap {
  width: 100%;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 8px 12px;
}

.status-badge {
  padding: 7px 11px;
  border-radius: 999px;
  font-size: 0.84rem;
  font-weight: 700;
  color: var(--text-soft);
  background: rgba(23, 48, 58, 0.08);
}

.board-status {
  margin: 0;
  min-height: 1.4em;
  font-size: clamp(0.96rem, 1.7vw, 1.08rem);
  font-weight: 700;
  text-align: center;
  transition: color var(--transition-fast), transform var(--transition-fast), opacity var(--transition-fast);
}

.board-status.is-updating {
  transform: translateY(-3px);
  opacity: 0.7;
}

.board-status[data-tone="win"] {
  color: var(--success);
}

.board-status[data-tone="draw"] {
  color: var(--warning);
}

.board-status[data-tone="thinking"] {
  color: var(--text-soft);
}

.board-stage {
  --board-padding: clamp(8px, 1.2vw, 12px);
  position: relative;
  align-self: center;
  justify-self: center;
  width: min(100%, var(--board-max));
  aspect-ratio: 1;
  padding: var(--board-padding);
  border-radius: calc(var(--radius-lg) + 2px);
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.88), rgba(247, 241, 231, 0.92)),
    linear-gradient(135deg, rgba(210, 95, 77, 0.08), rgba(44, 122, 120, 0.08));
  border: 1px solid rgba(23, 48, 58, 0.08);
  overflow: hidden;
  transition: transform var(--transition-smooth), box-shadow var(--transition-smooth), opacity var(--transition-fast);
}

.board-stage.is-resizing {
  box-shadow: inset 0 0 0 1px rgba(39, 95, 96, 0.1);
}

.board-stage.is-resizing[data-direction="grow"] {
  transform: scale(1.012);
}

.board-stage.is-resizing[data-direction="shrink"] {
  transform: scale(0.988);
}

.board-grid,
.board-ghosts {
  position: absolute;
  inset: var(--board-padding);
}

.board-grid {
  display: grid;
  gap: clamp(5px, 0.9vw, 9px);
  align-content: stretch;
  justify-content: stretch;
  z-index: 0;
}

.board-ghosts {
  pointer-events: none;
  z-index: 3;
}

.board-stage.is-bot-thinking::after {
  content: "";
  position: absolute;
  inset: var(--board-padding);
  border-radius: calc(var(--radius-lg) - 4px);
  background: rgba(23, 48, 58, 0.06);
  backdrop-filter: blur(2px);
  pointer-events: none;
  z-index: 1;
}

.board-stage.is-bot-thinking .board-grid {
  opacity: 0.78;
  filter: saturate(0.88);
}

.board-cell {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  aspect-ratio: 1;
  padding: 0;
  border: 0;
  border-radius: var(--radius-md);
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.98), rgba(246, 238, 228, 0.96));
  box-shadow:
    inset 0 0 0 1px rgba(23, 48, 58, 0.06),
    0 8px 20px rgba(23, 48, 58, 0.04);
  cursor: pointer;
  transition:
    transform var(--transition-fast),
    box-shadow var(--transition-fast),
    background var(--transition-fast),
    opacity var(--transition-fast);
  -webkit-tap-highlight-color: transparent;
}

.board-cell:hover {
  transform: translateY(-1px);
  box-shadow:
    inset 0 0 0 1px rgba(23, 48, 58, 0.08),
    0 12px 24px rgba(23, 48, 58, 0.06);
}

.board-cell:active {
  transform: scale(0.97);
}

.board-cell.is-filled {
  cursor: default;
}

.board-cell.is-win {
  background:
    linear-gradient(180deg, rgba(255, 250, 242, 0.98), rgba(237, 249, 243, 0.98));
  box-shadow:
    inset 0 0 0 2px rgba(42, 125, 86, 0.2),
    0 10px 26px rgba(42, 125, 86, 0.08);
}

.board-cell.is-entering {
  opacity: 0;
  transform: scale(0.72);
}

.board-cell.is-locked {
  pointer-events: none;
  cursor: default;
}

.board-cell.is-locked:hover {
  transform: none;
  box-shadow:
    inset 0 0 0 1px rgba(23, 48, 58, 0.06),
    0 8px 20px rgba(23, 48, 58, 0.04);
}

.board-cell--ghost {
  position: absolute;
  margin: 0;
  z-index: 4;
  transition:
    transform var(--transition-smooth),
    width var(--transition-smooth),
    height var(--transition-smooth),
    left var(--transition-smooth),
    top var(--transition-smooth),
    opacity var(--transition-fast);
}

.mark {
  position: relative;
  display: block;
  width: 62%;
  height: 62%;
  animation: pop-in 220ms cubic-bezier(0.22, 1, 0.36, 1);
}

.mark--x::before,
.mark--x::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 50%;
  width: clamp(4px, 0.72vmin, 9px);
  height: 100%;
  border-radius: 999px;
  background: linear-gradient(180deg, #e3836f, var(--x-color));
  transform-origin: center;
}

.mark--x::before {
  transform: translate(-50%, -50%) rotate(45deg);
}

.mark--x::after {
  transform: translate(-50%, -50%) rotate(-45deg);
}

.mark--o {
  border-radius: 50%;
  border: clamp(4px, 0.72vmin, 9px) solid var(--o-color);
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.42);
}

.board-line {
  position: absolute;
  left: var(--line-x);
  top: var(--line-y);
  width: var(--line-length);
  height: clamp(4px, 0.7vmin, 8px);
  border-radius: 999px;
  background: linear-gradient(90deg, rgba(210, 95, 77, 0.82), rgba(44, 122, 120, 0.82));
  box-shadow: 0 8px 20px rgba(23, 48, 58, 0.16);
  transform-origin: left center;
  transform: translateY(-50%) rotate(var(--line-angle)) scaleX(0);
  opacity: 0;
  transition:
    opacity 140ms ease,
    transform 280ms cubic-bezier(0.16, 1, 0.3, 1);
  z-index: 2;
  pointer-events: none;
}

.board-line.is-visible {
  opacity: 1;
  transform: translateY(-50%) rotate(var(--line-angle)) scaleX(1);
}

.actions {
  width: 100%;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
}

.action-button,
.screen-switch {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 44px;
  padding: 10px 16px;
  border: 1px solid rgba(23, 48, 58, 0.12);
  border-radius: 999px;
  text-decoration: none;
  font: inherit;
  font-weight: 700;
  color: var(--text);
  background: rgba(255, 255, 255, 0.84);
  cursor: pointer;
  transition:
    transform var(--transition-fast),
    background var(--transition-fast),
    box-shadow var(--transition-fast),
    border-color var(--transition-fast),
    opacity var(--transition-fast);
}

.action-button {
  min-width: 150px;
}

.action-button:hover,
.screen-switch:hover {
  transform: translateY(-1px);
  background: rgba(255, 255, 255, 0.98);
  box-shadow: 0 12px 26px rgba(23, 48, 58, 0.06);
}

.action-button:active,
.screen-switch:active {
  transform: scale(0.98);
}

.action-button--primary {
  color: #f7faf9;
  background: linear-gradient(135deg, #1d4954, #275f60);
  border-color: transparent;
}

.action-button--primary:hover {
  background: linear-gradient(135deg, #20505d, #2b6968);
}

.screen-switch {
  min-width: 132px;
  background: rgba(23, 48, 58, 0.06);
}

.screen-switch--reverse {
  background: rgba(255, 255, 255, 0.9);
}

.screen-switch__icon {
  font-size: 1rem;
  line-height: 1;
}

.screen-nav {
  display: flex;
  justify-content: center;
}

.action-button:disabled,
.screen-switch:disabled {
  opacity: 0.55;
  cursor: wait;
  transform: none;
  box-shadow: none;
}

.chip-button:focus-visible,
.board-cell:focus-visible,
.action-button:focus-visible,
.screen-switch:focus-visible,
.screen:focus-visible {
  outline: 3px solid rgba(44, 122, 120, 0.32);
  outline-offset: 3px;
}

.content-header {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 14px;
}

.content-header .screen-switch--reverse {
  align-self: center;
  margin-top: 4px;
}

.content-copy {
  max-width: 38rem;
  display: grid;
  gap: 6px;
}

.content-scroll {
  min-height: 0;
  overflow: auto;
  overscroll-behavior: contain;
  padding-right: 6px;
  scrollbar-width: thin;
  scrollbar-color: rgba(39, 95, 96, 0.24) transparent;
  -webkit-overflow-scrolling: touch;
}

.content-scroll::-webkit-scrollbar {
  width: 10px;
}

.content-scroll::-webkit-scrollbar-track {
  background: transparent;
}

.content-scroll::-webkit-scrollbar-thumb {
  border: 2px solid transparent;
  border-radius: 999px;
  background: rgba(39, 95, 96, 0.22);
  background-clip: padding-box;
}

.content-sections {
  min-height: 0;
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
  gap: 14px;
}

.content-stack {
  display: grid;
  gap: 14px;
  align-content: start;
}

.content-card,
.faq-item {
  background: var(--surface-soft);
}

.content-card h2,
.content-card h3,
.faq-item h3 {
  font-size: 1rem;
  margin-bottom: 8px;
}

.content-card p,
.faq-item p {
  margin: 0;
  font-size: 0.94rem;
  line-height: 1.55;
  color: var(--text-soft);
}

.content-card p + p {
  margin-top: 10px;
}

.content-card a,
.faq-item a {
  color: var(--o-color);
  text-decoration: none;
}

.content-card a:hover,
.content-card a:focus-visible,
.faq-item a:hover,
.faq-item a:focus-visible {
  text-decoration: underline;
}

.content-list {
  margin: 0;
  padding-left: 18px;
  display: grid;
  gap: 8px;
  color: var(--text-soft);
  font-size: 0.94rem;
  line-height: 1.45;
}

.content-list--links {
  list-style: none;
  padding-left: 0;
}

.content-list--links a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
}

.content-list--links a::before {
  content: "→";
  color: var(--x-color);
}

.faq-list {
  display: grid;
  gap: 12px;
  align-content: start;
}

.noscript-note {
  margin: 2px 0 0;
  text-align: center;
  color: var(--warning);
  font-size: 0.9rem;
}

.error-page {
  display: grid;
  place-items: center;
}

.error-card {
  width: min(680px, calc(100% - 28px));
  padding: clamp(18px, 3vw, 28px);
  border-radius: var(--radius-xl);
  text-align: center;
}

.actions--error {
  margin-top: 16px;
  justify-content: center;
}

.site-footer {
  display: flex;
  justify-content: center;
  padding-top: 2px;
}

.site-footer__inner {
  display: flex;
  flex-direction: column;
  gap: 8px;
  justify-content: center;
  width: 100%;
}

.site-footer__links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px 14px;
}

.site-footer__links a {
  color: var(--text-muted);
  font-size: 0.8rem;
  font-weight: 600;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition:
    color var(--transition-fast),
    border-color var(--transition-fast);
}

.site-footer__links a:hover,
.site-footer__links a:focus-visible {
  color: var(--text-soft);
  border-bottom-color: currentColor;
}

.site-footer__credit {
  font-size: 0.79rem;
  font-weight: 500;
  line-height: 1.4;
  color: var(--text-muted);
  opacity: 0.82;
  text-align: center;
}

.site-footer__credit a {
  color: inherit;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition:
    border-color var(--transition-fast),
    color var(--transition-fast),
    opacity var(--transition-fast);
}

.site-footer__credit a:hover,
.site-footer__credit a:focus-visible {
  color: var(--text-soft);
  border-bottom-color: currentColor;
  opacity: 1;
}

.metrika-pixel {
  position: absolute;
  left: -9999px;
}

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

.article-document,
.article-document body {
  min-height: 100%;
  overflow: auto;
}

body.article-page {
  min-height: 100vh;
}

.page-shell {
  position: relative;
  z-index: 1;
  min-height: 100vh;
  padding: clamp(14px, 2.6vw, 28px);
}

.page-stack {
  width: min(1120px, 100%);
  margin: 0 auto;
  display: grid;
  gap: 14px;
}

.breadcrumbs {
  font-size: 0.82rem;
  color: #67767d;
  font-weight: 500;
}

.breadcrumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  list-style: none;
  padding: 0;
  margin: 0;
}

.breadcrumbs li {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.breadcrumbs li + li::before {
  content: "/";
  color: rgba(23, 48, 58, 0.56);
}

.breadcrumbs a {
  color: #4d6068;
  text-decoration: none;
}

.breadcrumbs a:hover,
.breadcrumbs a:focus-visible {
  text-decoration: underline;
}

.article-frame,
.guide-frame {
  border-radius: var(--radius-xl);
  padding: clamp(16px, 2.2vw, 26px);
  border: 1px solid rgba(23, 48, 58, 0.1);
  background: rgba(255, 253, 249, 0.95);
}

.article-header,
.guide-header {
  max-width: 48rem;
  display: grid;
  gap: 8px;
}

.article-header h1,
.guide-header h1 {
  color: #273b45;
  font-weight: 700;
}

.article-lead,
.guide-lead {
  margin: 0;
  color: #4c5e67;
  font-size: 1rem;
  line-height: 1.68;
}

.article-content {
  margin-top: 18px;
  display: grid;
  gap: 14px;
}

.article-section,
.guide-highlight,
.guide-card {
  border-radius: var(--radius-lg);
  padding: clamp(16px, 2vw, 22px);
  background: rgba(255, 255, 255, 0.84);
  box-shadow:
    inset 0 0 0 1px rgba(23, 48, 58, 0.06),
    0 10px 24px rgba(23, 48, 58, 0.03);
}

.article-section h2,
.article-section h3,
.guide-highlight h2,
.guide-card h2,
.guide-card h3 {
  margin-bottom: 10px;
  color: #2a3f49;
}

.article-section p,
.article-section li,
.guide-highlight p,
.guide-highlight li,
.guide-card p,
.guide-card li {
  color: #465962;
  font-size: 0.98rem;
  line-height: 1.7;
}

.article-section p + p,
.guide-card p + p,
.guide-highlight p + p {
  margin-top: 12px;
}

.article-section ul,
.guide-highlight ul,
.guide-card ul {
  margin: 0;
  padding-left: 20px;
  display: grid;
  gap: 8px;
}

.article-section a,
.guide-highlight a,
.guide-card a,
.guide-grid a {
  color: var(--o-color);
  text-decoration: none;
}

.article-section a:hover,
.article-section a:focus-visible,
.guide-highlight a:hover,
.guide-highlight a:focus-visible,
.guide-card a:hover,
.guide-card a:focus-visible,
.guide-grid a:hover,
.guide-grid a:focus-visible {
  text-decoration: underline;
}

.cta-card {
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.92), rgba(245, 239, 230, 0.96)),
    radial-gradient(circle at top left, rgba(210, 95, 77, 0.08), transparent 48%);
}

.cta-card p:last-of-type {
  margin-bottom: 0;
}

.cta-actions {
  margin-top: 16px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.related-grid,
.guide-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.related-card,
.guide-card {
  display: grid;
  gap: 8px;
}

.related-card {
  border-radius: var(--radius-lg);
  padding: 16px;
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid rgba(23, 48, 58, 0.08);
}

.related-card h3,
.guide-card h3 {
  margin: 0;
  font-size: 1rem;
}

.related-card p,
.guide-card p {
  margin: 0;
  color: var(--text-soft);
  font-size: 0.94rem;
  line-height: 1.55;
}

.guide-highlight {
  display: grid;
  gap: 10px;
}

.guide-highlight__links,
.guide-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 10px;
}

.guide-highlight__links a,
.guide-list a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
}

.guide-highlight__links a::before,
.guide-list a::before {
  content: "→";
  color: var(--x-color);
}

.guide-card__meta {
  color: #566971;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

@keyframes pop-in {
  from {
    opacity: 0;
    transform: scale(0.6);
  }

  to {
    opacity: 1;
    transform: scale(1);
  }
}

@keyframes pattern-drift {
  from {
    transform: translate3d(-8px, -6px, 0);
  }

  to {
    transform: translate3d(8px, 6px, 0);
  }
}

@media (max-width: 980px) {
  :root {
    --board-max: min(56vw, calc(var(--viewport-height) - 340px), 360px);
  }

  .game-panel {
    grid-template-columns: 1fr;
  }

  .toolbar {
    order: 2;
  }

  .board-panel {
    order: 1;
  }

  .content-sections {
    grid-template-columns: 1fr;
  }

  .game-panel[data-mode="bot"] .bot-settings {
    grid-template-columns: 1fr;
  }

  .content-header {
    flex-direction: column;
    align-items: stretch;
  }

  .related-grid,
  .guide-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  :root {
    --board-max: min(58vw, calc(var(--viewport-height) - 360px), 300px);
  }

  .screen {
    padding: 10px;
  }

  .background-pattern {
    background-size: 164px 164px;
    opacity: 0.05;
  }

  .game-screen-card,
  .content-screen-card {
    border-radius: 22px;
  }

  .game-screen-card {
    padding: 12px;
    gap: 10px;
  }

  .content-screen-card {
    padding: 14px;
  }

  .content-scroll {
    padding-right: 2px;
  }

  .page-menu a {
    min-height: 36px;
    padding: 8px 12px;
    font-size: 0.8rem;
  }

  h1 {
    font-size: clamp(1.7rem, 8vw, 2.45rem);
  }

  .subtitle,
  .content-lead {
    font-size: 0.92rem;
  }

  .toolbar,
  .board-panel,
  .content-card,
  .faq-item {
    padding: 12px;
  }

  .chip-button {
    min-height: 38px;
    padding: 8px 12px;
    font-size: 0.88rem;
  }

  .game-panel[data-mode="bot"] {
    --board-max: min(58vw, calc(var(--viewport-height) - 392px), 300px);
  }

  .chip-row--sizes .chip-button {
    flex: 1 1 calc(50% - 8px);
    justify-content: center;
  }

  .chip-row--split .chip-button {
    flex: 1 1 100%;
    justify-content: center;
  }

  .actions,
  .screen-nav {
    flex-direction: column;
  }

  .action-button,
  .screen-switch {
    width: 100%;
  }

  .cta-actions {
    flex-direction: column;
  }
}

@media (max-height: 760px) {
  :root {
    --board-max: min(52vmin, calc(var(--viewport-height) - 300px), 360px);
  }

  .game-screen-card {
    padding: 12px;
    gap: 8px;
  }

  .toolbar,
  .board-panel {
    padding: 12px;
  }

  .eyebrow {
    padding: 5px 9px;
    font-size: 0.68rem;
  }

  h1 {
    font-size: clamp(1.72rem, 4vw, 2.7rem);
  }

  .subtitle {
    font-size: 0.9rem;
    line-height: 1.35;
  }

  .group-heading p,
  .content-lead {
    font-size: 0.8rem;
  }

  .chip-button,
  .action-button,
  .screen-switch {
    min-height: 38px;
  }
}

@media (max-height: 680px) {
  .screen-game .group-heading p {
    display: none;
  }

  .content-header .eyebrow {
    display: none;
  }

  .game-panel {
    gap: 10px;
  }
}

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

  .background-pattern-motion {
    animation: none;
  }
}