/* ============================================
  Chess Learning Game — Styles
  Target: 5-year-old on iPad, offline, touch
  ============================================ */

:root {
  --chess-bg: #1a1a2e;
  --chess-fg: #f5f5f5;
  --chess-accent: #e94560;
  --chess-accent2: #0f3460;
  --chess-success: #4ecdc4;
  --chess-warning: #ffe66d;
  --chess-light-sq: #f0d9b5;
  --chess-dark-sq: #b58863;
  --chess-highlight: rgba(255, 230, 109, 0.6);
  --chess-valid: rgba(78, 205, 196, 0.5);
  --chess-selected: rgba(233, 69, 96, 0.4);
  --chess-radius: 16px;
  --chess-font: -apple-system, 'Helvetica Neue', sans-serif;
}

* {
  box-sizing: border-box;
  -webkit-tap-highlight-color: transparent;
}

html, body {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: var(--chess-bg);
  color: var(--chess-fg);
  font-family: var(--chess-font);
  touch-action: manipulation;
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  user-select: none;
}

#app {
  width: 100%;
  height: 100dvh;
  display: flex;
  flex-direction: column;
  align-items: center;
  overflow: hidden;
}

/* ---- Screens ---- */

.screen {
  display: none;
  flex-direction: column;
  align-items: center;
  width: 100%;
  height: 100%;
  padding: 16px;
  overflow-y: auto;
}

.screen.active {
  display: flex;
}

/* ---- Home Screen ---- */

.game-title {
  font-size: clamp(2rem, 8vw, 3.5rem);
  font-weight: 800;
  margin: 24px 0 8px;
  text-align: center;
  background: linear-gradient(135deg, var(--chess-accent), var(--chess-warning));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.game-subtitle {
  font-size: clamp(1rem, 4vw, 1.5rem);
  opacity: 0.7;
  margin: 0 0 32px;
  text-align: center;
}

.mode-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  width: 100%;
  max-width: 400px;
  padding: 0 16px;
}

.mode-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 28px 20px;
  border: none;
  border-radius: var(--chess-radius);
  background: linear-gradient(135deg, var(--chess-accent2), #16213e);
  color: var(--chess-fg);
  font-family: var(--chess-font);
  font-size: 1.2rem;
  font-weight: 700;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  box-shadow: 0 4px 15px rgba(0,0,0,0.3);
  min-height: 100px;
}

.mode-card:active {
  transform: scale(0.95);
  box-shadow: 0 2px 8px rgba(0,0,0,0.4);
}

.mode-icon {
  font-size: 2.5rem;
}

.mode-label {
  font-size: clamp(1rem, 4vw, 1.3rem);
}

/* ---- Screen Header ---- */

.screen-header {
  display: flex;
  align-items: center;
  width: 100%;
  max-width: 600px;
  gap: 12px;
  margin-bottom: 12px;
  flex-shrink: 0;
}

.screen-title {
  flex: 1;
  text-align: center;
  font-size: clamp(1.2rem, 5vw, 1.8rem);
  margin: 0;
}

.back-btn, .reset-btn {
  background: var(--chess-accent2);
  border: none;
  border-radius: 12px;
  color: var(--chess-fg);
  font-family: var(--chess-font);
  font-size: 1rem;
  font-weight: 600;
  padding: 10px 16px;
  cursor: pointer;
  white-space: nowrap;
}

.back-btn:active, .reset-btn:active {
  transform: scale(0.95);
}

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

.board-container {
  display: flex;
  align-items: center;
  justify-content: center;
  flex: 1;
  width: 100%;
  max-width: 600px;
  min-height: 0;
}

.chess-board {
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  grid-template-rows: repeat(8, 1fr);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 4px 20px rgba(0,0,0,0.4);
  touch-action: none;
}

.chess-square {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  aspect-ratio: 1;
}

.chess-square.light {
  background: var(--chess-light-sq);
}

.chess-square.dark {
  background: var(--chess-dark-sq);
}

.chess-square.selected {
  background: var(--chess-selected);
}

.chess-square.valid-move::after {
  content: '';
  position: absolute;
  width: 35%;
  height: 35%;
  border-radius: 50%;
  background: var(--chess-valid);
  pointer-events: none;
  outline: 3px solid rgba(128, 0, 0, 0.5);
  outline-offset: -6px;
}

.chess-square.valid-capture::after {
  content: '';
  position: absolute;
  width: 80%;
  height: 80%;
  border-radius: 50%;
  background: var(--chess-valid);
  opacity: 0.5;
  pointer-events: none;
  border: 2px solid rgba(0, 0, 0, 0.3);
  z-index: 2;
}

.chess-square.highlight {
  background: var(--chess-highlight);
}

.chess-square.target-star::after {
  content: '⭐';
  position: absolute;
  font-size: clamp(1.2rem, 5vw, 2rem);
  pointer-events: none;
}

.chess-piece {
  width: 85%;
  height: 85%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: clamp(1.5rem, 7vw, 3rem);
  cursor: grab;
  z-index: 1;
  transition: transform 0.1s ease;
  line-height: 1;
}

.piece-white {
  color: var(--chess-fg);
}

.piece-black {
  color: var(--chess-bg);
}

.chess-piece.dragging {
  z-index: 100;
  transform: scale(1.2);
  cursor: grabbing;
  filter: drop-shadow(0 4px 8px rgba(0,0,0,0.4));
  transition: none;
}

.chess-piece.wobble {
  animation: wobble 0.4s ease;
}

@keyframes wobble {
  0%, 100% { transform: translateX(0); }
  20% { transform: translateX(-6px); }
  40% { transform: translateX(6px); }
  60% { transform: translateX(-4px); }
  80% { transform: translateX(4px); }
}

/* ---- File/Rank Labels ---- */

.board-wrapper {
  display: grid;
  grid-template-columns: auto 1fr;
  grid-template-rows: 1fr auto;
  gap: 4px;
  width: min(calc(100vw - 32px), calc(100dvh - 180px), 560px);
  aspect-ratio: 1;
}

.rank-labels {
  display: flex;
  flex-direction: column;
  justify-content: space-around;
  padding-right: 4px;
}

.file-labels {
  display: flex;
  justify-content: space-around;
  padding-top: 4px;
  grid-column: 2;
}

.board-label {
  font-size: clamp(0.6rem, 2.5vw, 0.9rem);
  font-weight: 700;
  opacity: 0.6;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ---- Hint Text ---- */

.hint-text, .puzzle-instruction {
  font-size: clamp(0.9rem, 3.5vw, 1.2rem);
  text-align: center;
  opacity: 0.8;
  margin: 8px 0;
  min-height: 2em;
  flex-shrink: 0;
}

.puzzle-instruction {
  font-weight: 700;
  font-size: clamp(1rem, 4vw, 1.4rem);
  color: var(--chess-warning);
}

/* ---- Meet the Pieces ---- */

#meet-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 100%;
  max-width: 500px;
  text-align: center;
  gap: 16px;
  min-height: 0;
}

.meet-piece-display {
  font-size: clamp(4rem, 20vw, 8rem);
  line-height: 1;
}

.meet-piece-name {
  font-size: clamp(1.5rem, 6vw, 2.5rem);
  font-weight: 800;
  color: var(--chess-warning);
}

.meet-piece-desc {
  font-size: clamp(1rem, 4vw, 1.4rem);
  opacity: 0.85;
  line-height: 1.5;
  padding: 0 16px;
}

.meet-mini-board {
  width: min(280px, 70vw);
  aspect-ratio: 1;
  margin: 8px auto;
}

.meet-mini-board .chess-board {
  width: 100%;
  height: 100%;
}

.meet-nav, .puzzle-nav {
  display: flex;
  align-items: center;
  gap: 24px;
  padding: 12px 0;
  flex-shrink: 0;
}

.nav-arrow {
  background: var(--chess-accent2);
  border: none;
  border-radius: 50%;
  width: 56px;
  height: 56px;
  color: var(--chess-fg);
  font-size: 1.4rem;
  font-weight: 700;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
}

.nav-arrow:active {
  transform: scale(0.9);
}

.nav-arrow:disabled {
  opacity: 0.3;
}

#meet-counter, #puzzle-counter {
  font-size: 1rem;
  opacity: 0.7;
}

/* ---- Celebration ---- */

.celebration {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  pointer-events: none;
  z-index: 200;
}

.celebration.hidden {
  display: none;
}

.confetti-piece {
  position: absolute;
  width: 12px;
  height: 12px;
  border-radius: 2px;
  animation: confetti-fall 1.5s ease forwards;
}

@keyframes confetti-fall {
  0% {
    opacity: 1;
    transform: translateY(0) rotate(0deg) scale(1);
  }
  100% {
    opacity: 0;
    transform: translateY(80vh) rotate(720deg) scale(0.5);
  }
}

.celebration-text {
  font-size: clamp(2rem, 10vw, 4rem);
  font-weight: 900;
  color: var(--chess-warning);
  text-shadow: 0 2px 10px rgba(0,0,0,0.5);
  animation: celebrate-pop 0.5s ease;
  z-index: 201;
}

@keyframes celebrate-pop {
  0% { transform: scale(0); opacity: 0; }
  60% { transform: scale(1.2); }
  100% { transform: scale(1); opacity: 1; }
}

/* ---- Floating piece while dragging ---- */

.floating-piece {
  position: fixed;
  pointer-events: none;
  z-index: 1000;
  font-size: clamp(2rem, 9vw, 4rem);
  line-height: 1;
  transform: translate(-50%, -80%);
  filter: drop-shadow(0 4px 12px rgba(0,0,0,0.5));
}

/* ---- Captured flash ---- */

@keyframes capture-flash {
  0% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.5); opacity: 0.5; }
  100% { transform: scale(0); opacity: 0; }
}

.capture-anim {
  animation: capture-flash 0.3s ease forwards;
}

/* ---- Turn Indicator ---- */

.turn-indicator {
  font-size: clamp(0.9rem, 3.5vw, 1.2rem);
  font-weight: 700;
  text-align: center;
  padding: 6px 16px;
  border-radius: 20px;
  margin-bottom: 4px;
  flex-shrink: 0;
  transition: background 0.3s ease, color 0.3s ease;
}

.turn-indicator.your-turn {
  background: var(--chess-success);
  color: #1a1a2e;
}

.turn-indicator.computer-turn {
  background: var(--chess-accent2);
  color: var(--chess-fg);
}

.turn-indicator.game-over {
  background: var(--chess-warning);
  color: #1a1a2e;
  font-size: clamp(1.1rem, 4vw, 1.5rem);
}

/* ---- Captured Pieces ---- */

.captured-pieces {
  display: flex;
  flex-direction: column;
  gap: 4px;
  width: 100%;
  max-width: 600px;
  padding: 4px 8px;
  flex-shrink: 0;
}

.captured-row {
  display: flex;
  flex-wrap: wrap;
  gap: 2px;
  font-size: clamp(1rem, 4vw, 1.5rem);
  min-height: 1.6em;
  align-items: center;
}

.captured-label {
  font-size: clamp(0.7rem, 2.5vw, 0.85rem);
  opacity: 0.6;
  margin-right: 6px;
}

/* ---- Computer thinking animation ---- */

.chess-board.thinking {
  opacity: 0.85;
  pointer-events: none;
}

.thinking-dots::after {
  content: '';
  animation: dots 1.2s steps(4, end) infinite;
}

@keyframes dots {
  0% { content: ''; }
  25% { content: '.'; }
  50% { content: '..'; }
  75% { content: '...'; }
}

/* ---- Last move highlight ---- */

.chess-square.last-move {
  /* background: rgba(255, 230, 109, 0.35); */
  outline: 3px solid rgba(128, 0, 0, 0.5);
  outline-offset: -6px;
}

/* ---- Flipped board (when playing as black) ---- */

.board-flipped .chess-board {
  transform: rotate(180deg);
}

.board-flipped .chess-board .chess-piece,
.board-flipped .chess-board .valid-move::after,
.board-flipped .chess-board .valid-capture::after,
.board-flipped .chess-board .target-star::after {
  transform: rotate(180deg);
}

/* ============================================
   Landscape layout (iPad and similar)
   ============================================ */

@media (orientation: landscape) and (max-height: 820px) {

  .screen {
    padding: 8px 16px;
  }

  /* ---- Home screen: 2×2 grid ---- */

  .game-title {
    margin: 8px 0 4px;
  }

  .game-subtitle {
    margin: 0 0 12px;
  }

  .mode-grid {
    grid-template-columns: 1fr 1fr;
    max-width: 600px;
    gap: 12px;
  }

  .mode-card {
    padding: 16px 12px;
    min-height: 70px;
    gap: 6px;
  }

  .mode-icon {
    font-size: 1.8rem;
  }

  /* ---- Screen header: compact ---- */

  .screen-header {
    margin-bottom: 6px;
    max-width: none;
  }

  /* ---- Board sizing in landscape ---- */

  .board-wrapper {
    width: min(calc(100vw - 32px), calc(100dvh - 100px), 560px);
  }

  /* ---- Game screens: board + info side by side ---- */

  #freeplay-screen,
  #computer-screen {
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: center;
    align-items: flex-start;
    gap: 8px;
  }

  #freeplay-screen > .screen-header,
  #computer-screen > .screen-header {
    width: 100%;
    flex-shrink: 0;
  }

  #freeplay-screen > .board-container,
  #computer-screen > .board-container {
    flex: 0 0 auto;
    width: auto;
    max-width: none;
  }

  #computer-screen > .turn-indicator {
    width: 100%;
    order: -1;
  }

  #freeplay-screen > .hint-text,
  #computer-screen > .hint-text {
    flex: 1;
    min-width: 140px;
    max-width: 200px;
    align-self: center;
    text-align: left;
  }

  #computer-screen > .captured-pieces {
    flex: 1;
    min-width: 140px;
    max-width: 220px;
    align-self: center;
  }

  /* ---- Meet the pieces: horizontal layout ---- */

  #meet-screen {
    overflow-y: hidden;
  }

  #meet-content {
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: center;
    max-width: none;
    gap: 8px;
  }

  .meet-piece-display {
    font-size: clamp(3rem, 12vw, 5rem);
  }

  .meet-piece-name {
    font-size: clamp(1.2rem, 3vw, 1.6rem);
  }

  .meet-piece-desc {
    font-size: clamp(0.85rem, 2.5vw, 1.1rem);
    max-width: 30ch;
  }

  .meet-mini-board {
    width: min(240px, calc(100dvh - 140px));
  }

  /* ---- Puzzle screen: landscape ---- */

  #puzzle-screen {
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: center;
    align-items: flex-start;
    gap: 8px;
  }

  #puzzle-screen > .screen-header {
    width: 100%;
  }

  #puzzle-screen > .puzzle-instruction {
    flex: 1;
    min-width: 140px;
    max-width: 220px;
    align-self: center;
  }

  /* ---- Nav arrows: smaller in landscape ---- */

  .nav-arrow {
    width: 44px;
    height: 44px;
    font-size: 1.1rem;
  }

  .meet-nav, .puzzle-nav {
    padding: 6px 0;
    gap: 16px;
  }
}

/* Extra-wide landscape (e.g. iPad Pro landscape) */
@media (orientation: landscape) and (min-width: 1024px) {

  .mode-grid {
    grid-template-columns: repeat(2, 1fr);
    max-width: 800px;
  }

  .mode-card {
    flex-direction: row;
    gap: 10px;
    padding: 20px 16px;
    justify-content: flex-start;
  }
}