:root {
  --color-bg: #F5F0EB;
  --color-fg: #2C2825;
  --color-card-face: #FEFCF9;
  --color-card-back: #3D3632;
  --color-suit-red: #C45B4A;
  --color-suit-dark: #2C2825;
  --color-accent-correct: #5B8C6B;
  --color-accent-wrong: #B85C5C;
  --color-accent-push: #C4A55B;
  --color-btn-bg: #E8E2DB;
  --color-btn-hover: #DDD6CE;

  --font-family: 'Inter', system-ui, -apple-system, sans-serif;

  --fs-card-value: 3.5rem;
  --fw-card-value: 700;
  --lh-card-value: 1.0;
  --ls-card-value: -0.02em;

  --fs-card-suit: 1.25rem;
  --fs-card-pip: 1rem;

  --fs-streak-playing: 1.25rem;
  --fw-streak-playing: 600;

  --fs-streak-gameover: 3rem;
  --fw-streak-gameover: 700;
  --ls-streak-gameover: -0.02em;

  --fs-btn: 1rem;
  --fw-btn: 600;
  --ls-btn: 0.02em;

  --fs-secondary: 0.875rem;
  --fw-secondary: 400;

  --fs-title: 0.75rem;
  --fw-title: 500;
  --ls-title: 0.08em;

  --radius-card: 12px;
  --radius-btn: 8px;

  --shadow-card: 0 2px 8px rgba(44, 40, 37, 0.08);
  --shadow-btn-active: inset 0 1px 2px rgba(44, 40, 37, 0.1);

  --card-border: 1px solid rgba(44, 40, 37, 0.1);
  --card-max-w: 200px;
  --card-min-w: 140px;
  --card-aspect: 5 / 7;

  --flip-duration: 400ms;
  --flip-easing: cubic-bezier(0.25, 0.1, 0.25, 1.0);
  --perspective: 1000px;

  --transition-fast: 100ms ease-out;
  --transition-medium: 300ms ease-out;
}

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-family);
  background-color: var(--color-bg);
  color: var(--color-fg);
  min-height: 100vh;
  min-height: 100dvh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.game {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  min-height: 100dvh;
  max-width: 480px;
  margin: 0 auto;
  padding: 48px 24px;
}

/* --- Title --- */

.game-title {
  font-size: var(--fs-title);
  font-weight: var(--fw-title);
  letter-spacing: var(--ls-title);
  text-transform: uppercase;
  color: rgba(44, 40, 37, 0.6);
  margin-bottom: 32px;
}

/* --- Card --- */

.card-area {
  margin-bottom: 40px;
}

.card {
  width: min(var(--card-max-w), 50vw);
  min-width: var(--card-min-w);
  aspect-ratio: var(--card-aspect);
  perspective: var(--perspective);
}

.card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform var(--flip-duration) var(--flip-easing), box-shadow var(--transition-medium);
  transform-style: preserve-3d;
  will-change: transform;
}

.card-feedback-correct {
  box-shadow: 0 0 12px 4px var(--color-accent-correct);
  border-radius: var(--radius-card);
}

.card-feedback-wrong {
  box-shadow: 0 0 12px 4px var(--color-accent-wrong);
  border-radius: var(--radius-card);
}

.card-feedback-push {
  box-shadow: 0 0 12px 4px var(--color-accent-push);
  border-radius: var(--radius-card);
}

.card-inner.flipped {
  transform: rotateY(180deg);
}

.card-face {
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  border-radius: var(--radius-card);
  border: var(--card-border);
  overflow: hidden;
}

.card-front {
  background-color: var(--color-card-face);
  box-shadow: var(--shadow-card);
  transform: rotateY(180deg);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 6px;
}

.card-front[data-suit-color="red"] {
  color: var(--color-suit-red);
}

.card-front[data-suit-color="dark"] {
  color: var(--color-suit-dark);
}

/* --- Card corners --- */

.card-corner {
  position: absolute;
  display: flex;
  flex-direction: column;
  align-items: center;
  line-height: 1;
  font-size: 0.65rem;
  font-weight: 600;
}

.card-corner-tl {
  top: 6px;
  left: 6px;
}

.card-corner-br {
  bottom: 6px;
  right: 6px;
  transform: rotate(180deg);
}

.card-corner-value {
  font-size: 0.75rem;
  font-weight: 700;
}

.card-corner-suit {
  font-size: 0.6rem;
  line-height: 1;
}

/* --- Face card / Ace value + suit --- */

.card-value {
  font-size: var(--fs-card-value);
  font-weight: var(--fw-card-value);
  line-height: var(--lh-card-value);
  letter-spacing: var(--ls-card-value);
}

.card-suit {
  font-size: var(--fs-card-suit);
  margin-top: 2px;
}

.card-center-suit {
  font-size: 3rem;
  margin-top: 4px;
  opacity: 0.35;
}

/* --- Pip grid --- */

.pip-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  grid-template-rows: repeat(9, 1fr);
  width: 70%;
  height: 75%;
  align-items: center;
  justify-items: center;
}

.pip {
  font-size: var(--fs-card-pip);
  line-height: 1;
  text-align: center;
}

.pip-inverted {
  transform: rotate(180deg);
}

.card-back {
  background-color: var(--color-card-back);
  box-shadow: var(--shadow-card);
  background-image:
    repeating-linear-gradient(
      45deg,
      transparent,
      transparent 8px,
      rgba(245, 240, 235, 0.08) 8px,
      rgba(245, 240, 235, 0.08) 9px
    ),
    repeating-linear-gradient(
      -45deg,
      transparent,
      transparent 8px,
      rgba(245, 240, 235, 0.08) 8px,
      rgba(245, 240, 235, 0.08) 9px
    );
}

/* --- Streak --- */

.streak-display {
  font-size: var(--fs-streak-playing);
  font-weight: var(--fw-streak-playing);
  line-height: 1.2;
  text-align: center;
  transition: font-size var(--transition-medium), font-weight var(--transition-medium), transform 200ms ease-out;
}

.streak-pulse {
  transform: scale(1.05);
}

/* --- Cards Remaining --- */

.cards-remaining {
  font-size: var(--fs-secondary);
  font-weight: var(--fw-secondary);
  color: rgba(44, 40, 37, 0.5);
  text-align: center;
  line-height: 1.4;
  margin-bottom: 16px;
}

/* --- Buttons --- */

.button-stage {
  display: grid;
  width: 100%;
  max-width: 320px;
}

.button-stage > * {
  grid-area: 1 / 1;
}

.action-buttons {
  display: flex;
  gap: 16px;
  width: 100%;
  transition: opacity var(--transition-medium);
}

.btn {
  font-family: var(--font-family);
  font-size: var(--fs-btn);
  font-weight: var(--fw-btn);
  letter-spacing: var(--ls-btn);
  color: var(--color-fg);
  background-color: var(--color-btn-bg);
  border: none;
  border-radius: var(--radius-btn);
  cursor: pointer;
  min-height: 48px;
  min-width: 44px;
  padding: 12px 24px;
  transition: background-color var(--transition-fast), transform var(--transition-fast);
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}

.btn:active {
  transform: scale(0.96);
  box-shadow: var(--shadow-btn-active);
}

@media (hover: hover) {
  .btn:hover {
    background-color: var(--color-btn-hover);
  }
}

.btn:focus-visible {
  outline: 2px solid var(--color-fg);
  outline-offset: 2px;
}

.btn-higher,
.btn-lower {
  flex: 1;
}

.play-again-area {
  width: 100%;
  max-width: 320px;
  display: flex;
  justify-content: center;
  transition: opacity var(--transition-medium);
}

.btn-play-again {
  width: 100%;
}

/* --- Best Score --- */

.best-score {
  font-size: var(--fs-secondary);
  font-weight: var(--fw-secondary);
  color: rgba(44, 40, 37, 0.6);
  text-align: center;
  margin-top: 16px;
  transition: opacity var(--transition-medium);
}

/* --- Start button --- */

.start-area {
  width: 100%;
  max-width: 320px;
  display: flex;
  justify-content: center;
}

.btn-start {
  width: 100%;
}

/* --- State visibility --- */

[data-state="ready"] .streak-display,
[data-state="ready"] .cards-remaining,
[data-state="ready"] .play-again-area,
[data-state="ready"] .best-score,
[data-state="ready"] .action-buttons {
  display: none;
}

[data-state="playing"] .start-area,
[data-state="playing"] .play-again-area,
[data-state="playing"] .best-score {
  display: none;
}

[data-state="revealing"] .start-area {
  display: none;
}

[data-state="game-over"] .start-area {
  display: none;
}

[data-state="deck-complete"] .start-area {
  display: none;
}

[data-state="revealing"] .play-again-area,
[data-state="revealing"] .best-score {
  display: none;
}

[data-state="revealing"] .action-buttons .btn {
  opacity: 0.5;
  pointer-events: none;
}

[data-state="game-over"] .action-buttons {
  opacity: 0;
  pointer-events: none;
}

[data-state="game-over"] .cards-remaining {
  display: none;
}

[data-state="game-over"] .streak-display {
  font-size: var(--fs-streak-gameover);
  font-weight: var(--fw-streak-gameover);
  letter-spacing: var(--ls-streak-gameover);
}

[data-state="deck-complete"] .action-buttons {
  opacity: 0;
  pointer-events: none;
}

[data-state="deck-complete"] .cards-remaining {
  display: none;
}

[data-state="deck-complete"] .streak-display {
  font-size: var(--fs-streak-gameover);
  font-weight: var(--fw-streak-gameover);
  letter-spacing: var(--ls-streak-gameover);
  color: var(--color-accent-correct);
}

[data-state="deck-complete"] .card-inner {
  box-shadow: 0 0 20px 6px var(--color-accent-correct);
  border-radius: var(--radius-card);
}

/* --- Screen reader only --- */

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

/* --- Reduced motion --- */

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

  .card-inner {
    transition: none;
  }
}