:root {
  color-scheme: dark;
  --bg: #0f172a;
  --surface: #1e293b;
  --surface-2: #273449;
  --line: rgba(148, 163, 184, 0.16);
  --text: #e2e8f0;
  --muted: #94a3b8;
  --accent: #ec4899;
  --accent-strong: #db2777;
  --x: #ec4899;
  --x-soft: rgba(236, 72, 153, 0.16);
  --x-glow: rgba(236, 72, 153, 0.5);
  --o: #38bdf8;
  --o-soft: rgba(56, 189, 248, 0.14);
  --o-glow: rgba(56, 189, 248, 0.45);
  --radius: 12px;
  --shadow: 0 12px 32px rgba(2, 6, 23, 0.45), 0 2px 6px rgba(2, 6, 23, 0.3);
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
  --fast: 150ms;
  --med: 220ms;
  --font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  min-height: 100svh;
  display: flex;
  flex-direction: column;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.4;
  color: var(--text);
  background-color: var(--bg);
  background-image:
    radial-gradient(56rem 28rem at 90% -12%, rgba(236, 72, 153, 0.13), transparent 62%),
    radial-gradient(48rem 26rem at -8% 108%, rgba(56, 189, 248, 0.09), transparent 62%);
  background-repeat: no-repeat;
}

h1,
p {
  margin: 0;
}

button {
  font: inherit;
  color: inherit;
}

:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 2px;
}

[hidden] {
  display: none !important;
}

/* ---------- Buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  min-width: 44px;
  padding: 0 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  color: var(--text);
  font-weight: 600;
  font-size: 0.95rem;
  white-space: nowrap;
  cursor: pointer;
  box-shadow: 0 1px 2px rgba(2, 6, 23, 0.3);
  transition: background-color var(--fast) var(--ease), border-color var(--fast) var(--ease), transform var(--fast) var(--ease);
}

.btn:hover {
  background: var(--surface-2);
  border-color: rgba(148, 163, 184, 0.3);
}

.btn:active {
  transform: translateY(1px);
}

.btn-primary {
  background: var(--accent-strong);
  border-color: transparent;
  color: #fff;
  box-shadow: 0 6px 18px rgba(219, 39, 119, 0.35);
}

.btn-primary:hover {
  background: #be185d;
  border-color: transparent;
}

.btn-square {
  padding: 0;
  width: 44px;
  letter-spacing: 0.04em;
}

.btn-ghost {
  background: transparent;
  box-shadow: none;
  color: var(--muted);
  min-height: 40px;
  padding: 0 12px;
}

.btn-ghost:hover {
  color: var(--text);
}

/* ---------- Header & footer ---------- */

.topbar {
  width: 100%;
  max-width: 1040px;
  margin: 0 auto;
  padding: 12px 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.brand {
  flex: 1 1 auto;
  display: flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
}

.logo {
  width: 32px;
  height: 32px;
  flex: none;
}

.logo-bg {
  fill: var(--surface);
}

.logo-x,
.logo-o {
  fill: none;
  stroke-width: 3;
  stroke-linecap: round;
}

.logo-x {
  stroke: var(--x);
}

.logo-o {
  stroke: var(--o);
}

.brand h1 {
  font-size: 1.3rem;
  font-weight: 800;
  letter-spacing: -0.01em;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  padding-right: 0.1em; /* keeps the last glyph's overhang inside the clip */
}

.actions {
  display: flex;
  gap: 8px;
  flex: none;
}

/* Narrow phones: a tighter header so the whole title still fits beside the buttons. */
@media (max-width: 399px) {
  .topbar,
  .brand {
    gap: 8px;
  }

  .brand h1 {
    font-size: 1.1rem;
  }
}

@media (max-width: 359px) {
  .logo {
    display: none;
  }
}

.footer {
  padding: 16px;
  text-align: center;
  font-size: 0.85rem;
}

.footer a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  color: var(--muted);
  text-decoration: none;
  transition: color var(--fast) var(--ease);
}

.footer a:hover {
  color: var(--accent);
}

/* ---------- Layout ---------- */

.layout {
  flex: 1;
  width: 100%;
  max-width: 1040px;
  margin: 0 auto;
  padding: 4px 16px 8px;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  grid-template-areas: "scores" "play" "settings";
  align-content: start;
  gap: 14px;
}

.play {
  /* Fits the viewport height, but never below 240px, above 520px or wider than the column. */
  --board-size: min(100%, clamp(240px, 100svh - 290px, 520px));
  grid-area: play;
  align-content: start;
  display: grid;
  gap: 10px;
  justify-items: center;
}

/* Wide and tall enough: board left, panel right. Short landscape screens have their own layout at the end. */
@media (min-width: 860px) and (min-height: 501px) {
  .layout {
    grid-template-columns: minmax(0, 1fr) 320px;
    grid-template-areas: "play scores" "play settings";
    grid-template-rows: auto 1fr;
    column-gap: 36px;
    row-gap: 16px;
    padding-top: 16px;
  }
}

/* ---------- Scoreboard ---------- */

.scores {
  grid-area: scores;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
}

.score {
  display: grid;
  justify-items: center;
  gap: 2px;
  padding: 8px 6px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: border-color var(--med) var(--ease), box-shadow var(--med) var(--ease);
}

.score-head {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  max-width: 100%;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.score-mark {
  font-size: 0.95rem;
  font-weight: 800;
}

.score-x .score-mark {
  color: var(--x);
}

.score-o .score-mark {
  color: var(--o);
}

.score-value {
  font-size: 1.6rem;
  font-weight: 800;
  line-height: 1.15;
  font-variant-numeric: tabular-nums;
}

.score-x.is-turn {
  border-color: var(--x);
  box-shadow: var(--shadow), 0 0 0 1px var(--x), 0 0 18px var(--x-soft);
}

.score-o.is-turn {
  border-color: var(--o);
  box-shadow: var(--shadow), 0 0 0 1px var(--o), 0 0 18px var(--o-soft);
}

.bump {
  animation: bump 250ms var(--ease);
}

@keyframes bump {
  40% {
    transform: scale(1.25);
  }
}

@media (min-width: 860px) and (min-height: 501px) {
  .score {
    padding: 14px 8px;
  }

  .score-value {
    font-size: 2.1rem;
  }
}

/* ---------- Status ---------- */

.status-row {
  container-type: inline-size;
  width: var(--board-size);
  min-height: 44px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.status-row .btn {
  flex: none;
}

.status {
  font-size: 1.1rem;
  font-weight: 700;
  line-height: 1.2; /* two lines still fit in the 44px row, so a wrapped message never moves the board */
  min-width: 0;
  overflow-wrap: break-word;
}

/* Narrow rows (small phones, landscape): a smaller message and a slimmer button keep it on one line. */
@container (max-width: 320px) {
  .status {
    font-size: 1rem;
  }

  .status-row .btn {
    padding: 0 12px;
  }
}

@container (max-width: 220px) {
  .status {
    font-size: 0.9rem;
  }
}

.status[data-tone="X"] {
  color: var(--x);
}

.status[data-tone="O"] {
  color: var(--o);
}

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

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

@media (min-width: 860px) and (min-height: 501px) {
  .play {
    --board-size: min(100%, clamp(240px, 100svh - 220px, 520px));
  }
}

.board-card {
  width: var(--board-size);
  padding: 8px;
  background: linear-gradient(160deg, var(--surface-2), var(--surface) 55%);
  border: 1px solid var(--line);
  border-radius: calc(var(--radius) + 6px);
  box-shadow: var(--shadow);
}

.board-area {
  position: relative;
  aspect-ratio: 1;
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
  -webkit-tap-highlight-color: transparent;
}

.board {
  position: absolute;
  inset: 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
}

.cell {
  position: relative;
  margin: 0;
  padding: 0;
  border: 0;
  background: none;
  cursor: default;
  outline: none;
}

.cell::before {
  content: "";
  position: absolute;
  inset: 5px;
  border-radius: var(--radius);
  background: var(--bg);
  box-shadow: inset 0 2px 8px rgba(2, 6, 23, 0.55);
  transition: background-color var(--med) var(--ease), box-shadow var(--med) var(--ease);
}

.board.can-play .cell:not([data-mark]) {
  cursor: pointer;
}

.board.can-play .cell:not([data-mark]):hover::before {
  background: #15203a;
  box-shadow: inset 0 0 0 1px rgba(236, 72, 153, 0.35), inset 0 2px 8px rgba(2, 6, 23, 0.4);
}

.cell:focus-visible::before {
  box-shadow: inset 0 0 0 3px var(--accent), 0 0 0 1px rgba(236, 72, 153, 0.25);
}

.cell.is-win[data-mark="X"]::before {
  background: var(--x-soft);
}

.cell.is-win[data-mark="O"]::before {
  background: var(--o-soft);
}

.mark {
  position: absolute;
  inset: 18%;
  width: 64%;
  height: 64%;
  overflow: visible;
  fill: none;
  stroke-width: 11;
  stroke-linecap: round;
  pointer-events: none;
  transition: opacity var(--med) var(--ease);
}

.mark-x {
  stroke: var(--x);
  filter: drop-shadow(0 0 7px var(--x-glow));
}

.mark-o {
  stroke: var(--o);
  filter: drop-shadow(0 0 7px var(--o-glow));
}

.mark.is-new path {
  stroke-dasharray: 1;
  animation: draw 240ms var(--ease) both;
}

.mark.is-new path:nth-child(2) {
  animation-delay: 150ms;
}

.cell.is-dim .mark {
  opacity: 0.3;
}

@keyframes draw {
  0% {
    stroke-dashoffset: 1;
    opacity: 0;
  }

  1% {
    opacity: 1;
  }

  100% {
    stroke-dashoffset: 0;
    opacity: 1;
  }
}

.win-line {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  overflow: visible;
  pointer-events: none;
  visibility: hidden;
}

.win-line path {
  fill: none;
  stroke-width: 9;
  stroke-linecap: round;
  stroke: #fbcfe8;
  filter: drop-shadow(0 0 8px var(--x-glow));
}

.win-line[data-mark="O"] path {
  stroke: #bae6fd;
  filter: drop-shadow(0 0 8px var(--o-glow));
}

.win-line.is-shown {
  visibility: visible;
}

.win-line.is-shown path {
  stroke-dasharray: 1;
  animation: draw 250ms var(--ease) var(--fast) both;
}

/* ---------- Settings ---------- */

.settings {
  grid-area: settings;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  grid-template-areas: "mode mode" "mark difficulty" "foot foot";
  gap: 12px 10px;
  padding: 12px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.field {
  display: grid;
  gap: 6px;
  min-width: 0;
}

.field-mode {
  grid-area: mode;
}

.field-mark {
  grid-area: mark;
}

.field-difficulty {
  grid-area: difficulty;
}

.field-label {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
}

.segmented {
  display: flex;
  gap: 4px;
  padding: 4px;
  background: var(--bg);
  border-radius: var(--radius);
}

.segmented button {
  flex: 1 1 auto;
  min-width: 40px;
  min-height: 40px;
  padding: 0 6px;
  border: 0;
  border-radius: 9px;
  background: transparent;
  color: var(--muted);
  font-size: 0.85rem;
  font-weight: 600;
  white-space: nowrap;
  cursor: pointer;
  transition: background-color var(--fast) var(--ease), color var(--fast) var(--ease), box-shadow var(--fast) var(--ease);
}

.segmented button:hover {
  color: var(--text);
}

.segmented button[aria-pressed="true"] {
  background: var(--surface-2);
  color: var(--text);
  box-shadow: 0 1px 3px rgba(2, 6, 23, 0.5), inset 0 0 0 1px rgba(236, 72, 153, 0.45);
}

.segmented .seg-x,
.segmented .seg-o {
  font-size: 1.05rem;
  font-weight: 800;
}

.segmented .seg-x[aria-pressed="true"] {
  color: var(--x);
}

.segmented .seg-o[aria-pressed="true"] {
  color: var(--o);
  box-shadow: 0 1px 3px rgba(2, 6, 23, 0.5), inset 0 0 0 1px rgba(56, 189, 248, 0.45);
}

.settings-foot {
  grid-area: foot;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  flex-wrap: wrap;
}

.hint {
  font-size: 0.8rem;
  color: var(--muted);
  min-width: 0;
}

@media (max-width: 360px) {
  .settings {
    grid-template-columns: minmax(0, 1fr);
    grid-template-areas: "mode" "mark" "difficulty" "foot";
  }
}

@media (hover: none) {
  .hint {
    display: none;
  }

  .settings-foot {
    justify-content: flex-end;
  }
}

@media (min-width: 860px) and (min-height: 501px) {
  .settings {
    grid-template-columns: minmax(0, 1fr);
    grid-template-areas: "mode" "mark" "difficulty" "foot";
    gap: 16px;
    padding: 18px;
    align-self: start;
  }

  .segmented button {
    padding: 0 10px;
    font-size: 0.9rem;
  }

  .settings-foot {
    flex-direction: column;
    align-items: stretch;
    gap: 10px;
    padding-top: 4px;
    border-top: 1px solid var(--line);
  }

  .settings-foot .btn-ghost {
    align-self: flex-start;
    padding: 0 10px;
    margin-left: -10px;
  }
}

/* ---------- Short landscape screens (phones turned sideways) ---------- */

/* The board uses the full height on the left; scores and settings sit beside it. */
@media (orientation: landscape) and (max-height: 500px) and (min-width: 560px) {
  .topbar {
    padding-top: 8px;
    padding-bottom: 8px;
  }

  .layout {
    grid-template-columns: auto minmax(0, 360px);
    grid-template-areas: "play scores" "play settings";
    grid-template-rows: auto 1fr;
    justify-content: center;
    gap: 8px 20px;
    padding-top: 0;
  }

  .play {
    /* 120px = 60px header + 44px status row + 8px gap + 8px bottom padding; the side column keeps 320px. */
    --board-size: max(180px, min(100svh - 120px, 100vw - 372px));
    gap: 8px;
  }

  .score {
    padding-top: 6px;
    padding-bottom: 6px;
  }

  .settings {
    align-self: start;
    gap: 10px;
    padding: 10px 12px;
  }
}

/* ---------- Motion ---------- */

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
  }
}