/* ===== RESET & BASE ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --primary: #6c63ff;
  --primary-dark: #5a52d5;
  --secondary: #ff6584;
  --accent: #43e97b;
  --bg: #0f0e17;
  --bg2: #1a1a2e;
  --card: #16213e;
  --card2: #1e2d4d;
  --text: #fffffe;
  --text-muted: #a7a9be;
  --border: rgba(255,255,255,0.1);
  --shadow: 0 8px 32px rgba(0,0,0,0.4);
  --radius: 16px;
  --radius-sm: 8px;
  --transition: 0.2s ease;
}

/* Themes */
body.theme-ocean { --primary: #00b4d8; --primary-dark: #0090b0; --secondary: #48cae4; --accent: #90e0ef; --bg: #03045e; --bg2: #023e8a; --card: #0077b6; --card2: #0096c7; }
body.theme-forest { --primary: #40916c; --primary-dark: #2d6a4f; --secondary: #74c69d; --accent: #b7e4c7; --bg: #1b4332; --bg2: #2d6a4f; --card: #40916c; --card2: #52b788; }
body.theme-sunset { --primary: #f77f00; --primary-dark: #d62828; --secondary: #fcbf49; --accent: #ffd166; --bg: #370617; --bg2: #6a040f; --card: #9d0208; --card2: #d00000; }
body.theme-dark { --primary: #e0e0e0; --primary-dark: #bdbdbd; --secondary: #757575; --accent: #9e9e9e; --bg: #121212; --bg2: #1e1e1e; --card: #2d2d2d; --card2: #3d3d3d; }
body.theme-candy { --primary: #ff6eb4; --primary-dark: #e0559c; --secondary: #a78bfa; --accent: #67e8f9; --bg: #2d1b4e; --bg2: #3d2060; --card: #4a2575; --card2: #5a3085; }

body {
  font-family: 'Poppins', sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  overflow-x: hidden;
}

/* ===== SCREENS ===== */
.screen {
  display: none;
  min-height: 100vh;
  animation: fadeIn 0.3s ease;
}
.screen.active { display: block; }

@keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

/* ===== MAIN MENU ===== */
.menu-bg {
  position: fixed; top: 0; left: 0; width: 100%; height: 100%;
  pointer-events: none; z-index: 0;
}
.floating-piece {
  position: absolute;
  left: var(--x); top: var(--y);
  font-size: 2.5rem;
  animation: float 4s ease-in-out infinite;
  animation-delay: var(--delay);
  opacity: 0.15;
}
@keyframes float {
  0%, 100% { transform: translateY(0) rotate(0deg); }
  50% { transform: translateY(-20px) rotate(10deg); }
}

.menu-container {
  position: relative; z-index: 1;
  max-width: 480px; margin: 0 auto;
  padding: 40px 24px;
  display: flex; flex-direction: column;
  align-items: center; gap: 32px;
  min-height: 100vh; justify-content: center;
}

.logo-area { text-align: center; }
.game-title {
  font-family: 'Fredoka One', cursive;
  font-size: 3.5rem;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
  filter: drop-shadow(0 4px 24px rgba(108,99,255,0.4));
  line-height: 1;
}
.game-subtitle {
  color: var(--text-muted); font-size: 1rem; margin-top: 8px;
  letter-spacing: 2px; text-transform: uppercase;
}

.menu-buttons { display: flex; flex-direction: column; gap: 12px; width: 100%; }
.menu-footer { color: var(--text-muted); font-size: 0.8rem; text-align: center; }

/* ===== BUTTONS ===== */
.btn {
  padding: 14px 28px; border: none; border-radius: var(--radius);
  font-family: 'Poppins', sans-serif; font-size: 1rem; font-weight: 600;
  cursor: pointer; transition: all var(--transition);
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
}
.btn-large { padding: 16px 32px; font-size: 1.1rem; }
.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: white;
  box-shadow: 0 4px 20px rgba(108,99,255,0.4);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 28px rgba(108,99,255,0.5); }
.btn-primary:active { transform: translateY(0); }
.btn-secondary {
  background: var(--card); color: var(--text);
  border: 1px solid var(--border);
}
.btn-secondary:hover { background: var(--card2); transform: translateY(-2px); }
.btn-danger { background: #e63946; color: white; }
.btn-danger:hover { background: #c1121f; transform: translateY(-2px); }
.btn-icon {
  background: var(--card); border: 1px solid var(--border);
  color: var(--text); padding: 10px; border-radius: 50%;
  cursor: pointer; font-size: 1.2rem; transition: all var(--transition);
  width: 44px; height: 44px; display: flex; align-items: center; justify-content: center;
}
.btn-icon:hover { background: var(--card2); transform: scale(1.1); }
.btn-back {
  background: none; border: none; color: var(--text-muted);
  font-family: 'Poppins', sans-serif; font-size: 0.95rem;
  cursor: pointer; padding: 8px 12px; border-radius: var(--radius-sm);
  transition: all var(--transition);
}
.btn-back:hover { color: var(--text); background: var(--card); }

/* ===== SCREEN HEADER ===== */
.screen-header {
  display: flex; align-items: center; gap: 16px;
  padding: 20px 24px; border-bottom: 1px solid var(--border);
  background: var(--bg2);
}
.screen-header h2 { font-size: 1.3rem; font-weight: 700; }

/* ===== CATEGORY SCREEN ===== */
.category-container {
  max-width: 600px; margin: 0 auto;
  padding: 24px; display: flex; flex-direction: column; gap: 20px;
}
.section-title {
  font-size: 1.1rem; font-weight: 700; color: var(--text-muted);
  text-transform: uppercase; letter-spacing: 1px;
}

.image-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(110px, 1fr));
  gap: 12px;
}
.image-card {
  border-radius: var(--radius); overflow: hidden; cursor: pointer;
  border: 3px solid transparent; transition: all var(--transition);
  position: relative; aspect-ratio: 1;
  background: var(--card);
}
.image-card:hover { border-color: var(--primary); transform: scale(1.05); }
.image-card.selected { border-color: var(--accent); box-shadow: 0 0 20px rgba(67,233,123,0.4); }
.image-card canvas { width: 100%; height: 100%; display: block; }
.image-card-label {
  position: absolute; bottom: 0; left: 0; right: 0;
  background: rgba(0,0,0,0.7); padding: 4px 8px;
  font-size: 0.7rem; text-align: center; color: white;
}
.image-card .selected-badge {
  position: absolute; top: 6px; right: 6px;
  background: var(--accent); color: #000; border-radius: 50%;
  width: 22px; height: 22px; display: flex; align-items: center; justify-content: center;
  font-size: 0.75rem; font-weight: 700; opacity: 0; transition: opacity 0.2s;
}
.image-card.selected .selected-badge { opacity: 1; }

.difficulty-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px;
}
.difficulty-btn {
  background: var(--card); border: 2px solid var(--border);
  border-radius: var(--radius); padding: 16px 8px;
  cursor: pointer; transition: all var(--transition);
  display: flex; flex-direction: column; align-items: center; gap: 6px;
  color: var(--text); font-family: 'Poppins', sans-serif;
}
.difficulty-btn:hover { border-color: var(--primary); background: var(--card2); transform: translateY(-2px); }
.difficulty-btn.active { border-color: var(--primary); background: rgba(108,99,255,0.2); }
.diff-icon { font-size: 1.8rem; }
.diff-name { font-weight: 700; font-size: 0.95rem; }
.diff-desc { font-size: 0.75rem; color: var(--text-muted); }

/* ===== GAME SCREEN ===== */
.game-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 20px; background: var(--bg2);
  border-bottom: 1px solid var(--border);
  gap: 12px;
}
.game-stats { display: flex; gap: 12px; }
.stat-box {
  background: var(--card); border-radius: var(--radius-sm);
  padding: 8px 14px; text-align: center; min-width: 72px;
}
.stat-label { display: block; font-size: 0.65rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 1px; }
.stat-value { display: block; font-size: 1.2rem; font-weight: 700; color: var(--primary); font-variant-numeric: tabular-nums; }

.game-area {
  display: flex; flex-direction: column; align-items: center;
  padding: 20px 16px; gap: 16px;
}

.preview-container {
  display: flex; align-items: center; gap: 10px;
}
.preview-label { font-size: 0.8rem; color: var(--text-muted); }
#previewCanvas {
  border-radius: var(--radius-sm); border: 2px solid var(--border);
  width: 80px; height: 80px;
}

.puzzle-board {
  display: grid;
  gap: 3px;
  background: var(--card);
  border-radius: var(--radius);
  padding: 6px;
  box-shadow: var(--shadow);
  max-width: min(90vw, 480px);
  width: 100%;
}

.puzzle-tile {
  border-radius: 6px;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  position: relative;
  overflow: hidden;
  aspect-ratio: 1;
  user-select: none;
  background: var(--card2);
}
.puzzle-tile:not(.empty):hover {
  transform: scale(1.03);
  box-shadow: 0 4px 16px rgba(108,99,255,0.5);
  z-index: 2;
}
.puzzle-tile:not(.empty):active { transform: scale(0.97); }
.puzzle-tile.empty {
  cursor: default;
  background: var(--bg);
  opacity: 0.3;
}
.puzzle-tile.hint {
  box-shadow: 0 0 0 3px var(--accent), 0 0 20px rgba(67,233,123,0.4);
  animation: hintPulse 0.8s ease infinite alternate;
}
@keyframes hintPulse {
  from { box-shadow: 0 0 0 3px var(--accent), 0 0 10px rgba(67,233,123,0.3); }
  to { box-shadow: 0 0 0 3px var(--accent), 0 0 24px rgba(67,233,123,0.6); }
}
.puzzle-tile canvas { width: 100%; height: 100%; display: block; pointer-events: none; }
.tile-number {
  position: absolute; bottom: 3px; right: 5px;
  font-size: 0.65rem; font-weight: 700; color: rgba(255,255,255,0.7);
  text-shadow: 0 1px 3px rgba(0,0,0,0.8);
  line-height: 1;
}

.game-controls {
  display: flex; gap: 10px; justify-content: center;
  padding: 0 16px 20px; flex-wrap: wrap;
}
.game-controls .btn { padding: 10px 18px; font-size: 0.85rem; }

.peek-overlay {
  position: fixed; inset: 0; z-index: 100;
  background: rgba(0,0,0,0.85);
  display: flex; flex-direction: column;
  align-items: center; justify-content: center; gap: 16px;
}
.peek-overlay canvas {
  border-radius: var(--radius); max-width: 90vw; max-height: 70vh;
  border: 3px solid var(--primary);
}
.peek-overlay p { color: var(--text-muted); font-size: 0.9rem; }
.peek-overlay.hidden { display: none; }

/* sliding animation */
@keyframes slideMove {
  from { transform: scale(1.05); }
  to { transform: scale(1); }
}
.puzzle-tile.just-moved { animation: slideMove 0.15s ease; }

/* ===== WIN SCREEN ===== */
#screen-win {
  display: flex; align-items: center; justify-content: center;
  background: radial-gradient(circle at 50% 50%, var(--bg2), var(--bg));
}
.win-container {
  max-width: 480px; width: 100%;
  padding: 40px 24px; text-align: center;
  display: flex; flex-direction: column; align-items: center; gap: 20px;
}
.win-animation {
  font-size: 5rem;
  animation: winBounce 0.6s ease infinite alternate;
}
@keyframes winBounce {
  from { transform: scale(0.9) rotate(-5deg); }
  to { transform: scale(1.1) rotate(5deg); }
}
.win-title { font-family: 'Fredoka One', cursive; font-size: 2.5rem; color: var(--accent); }
.win-subtitle { color: var(--text-muted); }

.win-stats {
  display: grid; grid-template-columns: repeat(2, 1fr);
  gap: 12px; width: 100%;
}
.win-stat {
  background: var(--card); border-radius: var(--radius);
  padding: 16px; display: flex; flex-direction: column; align-items: center; gap: 4px;
}
.win-stat-icon { font-size: 1.4rem; }
.win-stat-label { font-size: 0.75rem; color: var(--text-muted); text-transform: uppercase; }
.win-stat-value { font-size: 1.4rem; font-weight: 700; color: var(--primary); }

.name-input { width: 100%; padding: 12px 16px; border-radius: var(--radius); border: 2px solid var(--border); background: var(--card); color: var(--text); font-family: 'Poppins', sans-serif; font-size: 1rem; outline: none; text-align: center; }
.name-input:focus { border-color: var(--primary); }
.name-input-area { width: 100%; }

.win-buttons { display: flex; flex-direction: column; gap: 10px; width: 100%; }

/* ===== TUTORIAL ===== */
.tutorial-container {
  max-width: 560px; margin: 0 auto;
  padding: 24px; display: flex; flex-direction: column; gap: 20px;
}
.tutorial-slides { position: relative; min-height: 360px; }
.tutorial-slide {
  display: none; flex-direction: column; align-items: center;
  text-align: center; gap: 16px; animation: fadeIn 0.3s ease;
}
.tutorial-slide.active { display: flex; }
.tutorial-icon { font-size: 4rem; }
.tutorial-slide h3 { font-size: 1.4rem; font-weight: 700; }
.tutorial-slide p { color: var(--text-muted); line-height: 1.7; }

.tutorial-demo {
  display: flex; align-items: center; gap: 20px; margin: 8px 0;
}
.demo-arrow { font-size: 2rem; color: var(--primary); }
.demo-board {
  display: grid; gap: 3px; background: var(--card);
  border-radius: var(--radius-sm); padding: 4px;
}
.demo-3x3 { grid-template-columns: repeat(3, 40px); }
.demo-tile {
  width: 40px; height: 40px;
  background: var(--card2); border-radius: 4px;
  display: flex; align-items: center; justify-content: center;
  font-weight: 700; font-size: 0.9rem;
}
.demo-tile.empty { background: var(--bg); opacity: 0.3; }
.demo-board.solved .demo-tile { background: rgba(67,233,123,0.3); }

.tutorial-tips { display: flex; flex-direction: column; gap: 10px; text-align: left; width: 100%; }
.tip-item {
  background: var(--card); border-radius: var(--radius-sm);
  padding: 12px 16px; font-size: 0.9rem; line-height: 1.5;
}

.difficulty-info { display: flex; flex-direction: column; gap: 12px; width: 100%; }
.diff-info-item {
  background: var(--card); border-radius: var(--radius-sm);
  padding: 14px 16px; display: flex; align-items: center; gap: 14px; text-align: left;
  font-size: 0.9rem;
}
.diff-badge {
  white-space: nowrap; padding: 6px 12px; border-radius: 20px;
  font-weight: 700; font-size: 0.8rem; min-width: 110px; text-align: center;
}
.diff-badge.easy { background: rgba(67,233,123,0.2); color: var(--accent); }
.diff-badge.normal { background: rgba(252,191,73,0.2); color: #fcbf49; }
.diff-badge.hard { background: rgba(230,57,70,0.2); color: #e63946; }

.score-info { display: flex; flex-direction: column; gap: 10px; width: 100%; }
.score-item {
  background: var(--card); border-radius: var(--radius-sm);
  padding: 12px 16px; display: flex; align-items: center; gap: 14px;
  font-size: 0.85rem; color: var(--text-muted);
}
.score-stars { font-size: 1.1rem; white-space: nowrap; }

.tutorial-nav {
  display: flex; align-items: center; justify-content: space-between;
  gap: 12px;
}
.slide-dots { display: flex; gap: 8px; }
.dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--border); transition: all 0.2s;
}
.dot.active { background: var(--primary); transform: scale(1.3); }

/* ===== LEADERBOARD ===== */
.leaderboard-container { max-width: 560px; margin: 0 auto; padding: 24px; }
.leaderboard-tabs { display: flex; gap: 8px; margin-bottom: 20px; }
.tab-btn {
  flex: 1; padding: 10px; background: var(--card); border: 2px solid var(--border);
  border-radius: var(--radius-sm); color: var(--text);
  font-family: 'Poppins', sans-serif; font-weight: 600; cursor: pointer;
  transition: all var(--transition);
}
.tab-btn.active { border-color: var(--primary); background: rgba(108,99,255,0.2); }
.leaderboard-list { display: flex; flex-direction: column; gap: 8px; }
.lb-item {
  background: var(--card); border-radius: var(--radius);
  padding: 16px; display: flex; align-items: center; gap: 12px;
}
.lb-rank { font-size: 1.5rem; min-width: 36px; text-align: center; }
.lb-info { flex: 1; }
.lb-name { font-weight: 700; font-size: 0.95rem; }
.lb-detail { font-size: 0.75rem; color: var(--text-muted); }
.lb-score { font-size: 1.2rem; font-weight: 700; color: var(--primary); }
.lb-empty { text-align: center; color: var(--text-muted); padding: 40px; font-size: 0.9rem; }

/* ===== SETTINGS ===== */
.settings-container { max-width: 560px; margin: 0 auto; padding: 24px; display: flex; flex-direction: column; gap: 24px; }
.setting-group { background: var(--card); border-radius: var(--radius); overflow: hidden; }
.setting-group-title { padding: 16px 20px; border-bottom: 1px solid var(--border); font-size: 1rem; font-weight: 700; }
.setting-item {
  display: flex; align-items: center; justify-content: space-between;
  padding: 16px 20px; border-bottom: 1px solid var(--border);
}
.setting-item:last-child { border-bottom: none; }
.setting-name { font-weight: 600; font-size: 0.95rem; }
.setting-desc { font-size: 0.8rem; color: var(--text-muted); margin-top: 2px; }

.toggle { position: relative; width: 48px; height: 26px; }
.toggle input { opacity: 0; width: 0; height: 0; }
.toggle-slider {
  position: absolute; inset: 0;
  background: var(--card2); border-radius: 13px; cursor: pointer;
  transition: 0.3s;
}
.toggle-slider::before {
  content: ''; position: absolute;
  width: 20px; height: 20px; border-radius: 50%;
  left: 3px; top: 3px;
  background: white; transition: 0.3s;
}
.toggle input:checked + .toggle-slider { background: var(--primary); }
.toggle input:checked + .toggle-slider::before { transform: translateX(22px); }

.theme-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; padding: 16px; }
.theme-btn {
  background: none; border: 2px solid var(--border); border-radius: var(--radius-sm);
  padding: 12px 8px; cursor: pointer; transition: all var(--transition);
  display: flex; flex-direction: column; align-items: center; gap: 8px;
  color: var(--text); font-family: 'Poppins', sans-serif; font-size: 0.8rem;
}
.theme-btn:hover { border-color: var(--primary); }
.theme-btn.active { border-color: var(--primary); background: rgba(108,99,255,0.15); }
.theme-preview {
  width: 48px; height: 32px; border-radius: 6px;
}
.theme-default { background: linear-gradient(135deg, #6c63ff, #ff6584); }
.theme-ocean { background: linear-gradient(135deg, #00b4d8, #48cae4); }
.theme-forest { background: linear-gradient(135deg, #40916c, #74c69d); }
.theme-sunset { background: linear-gradient(135deg, #f77f00, #d62828); }
.theme-dark { background: linear-gradient(135deg, #424242, #757575); }
.theme-candy { background: linear-gradient(135deg, #ff6eb4, #a78bfa); }

/* ===== ABOUT ===== */
.about-container { max-width: 560px; margin: 0 auto; padding: 24px; display: flex; flex-direction: column; gap: 16px; align-items: center; }
.about-logo { font-size: 5rem; }
.about-title { font-family: 'Fredoka One', cursive; font-size: 2rem; background: linear-gradient(135deg, var(--primary), var(--secondary)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.about-version { color: var(--text-muted); font-size: 0.85rem; }
.about-card { background: var(--card); border-radius: var(--radius); padding: 20px; width: 100%; }
.about-card h3 { font-size: 1rem; font-weight: 700; margin-bottom: 10px; }
.about-card p { color: var(--text-muted); font-size: 0.9rem; line-height: 1.6; }
.feature-list { list-style: none; display: flex; flex-direction: column; gap: 6px; }
.feature-list li { color: var(--text-muted); font-size: 0.9rem; }
.link { color: var(--primary); text-decoration: none; }
.link:hover { text-decoration: underline; }

/* ===== CONFETTI ===== */
.confetti-piece {
  position: fixed; top: -10px;
  width: 10px; height: 10px;
  border-radius: 2px;
  animation: confettiFall linear forwards;
  z-index: 200; pointer-events: none;
}
@keyframes confettiFall {
  0% { transform: translateY(0) rotate(0deg); opacity: 1; }
  100% { transform: translateY(100vh) rotate(720deg); opacity: 0; }
}

/* ===== RESPONSIVE ===== */
@media (max-width: 480px) {
  .game-title { font-size: 2.8rem; }
  .win-stats { grid-template-columns: repeat(2, 1fr); }
  .game-controls .btn { padding: 8px 12px; font-size: 0.8rem; }
  .image-grid { grid-template-columns: repeat(auto-fill, minmax(90px, 1fr)); }
  .difficulty-grid { grid-template-columns: repeat(3, 1fr); }
  .diff-name { font-size: 0.8rem; }
  .diff-desc { font-size: 0.65rem; }
}