* { margin: 0; padding: 0; box-sizing: border-box; -webkit-tap-highlight-color: transparent; }

:root {
  --bg: #f8f8fa;
  --card: #ffffff;
  --card-border: #dddde4;
  --accent: #1890a8;
  --accent-dim: rgba(24, 144, 168, 0.1);
  --correct: #1a9a45;
  --correct-dim: rgba(26, 154, 69, 0.1);
  --wrong: #d03040;
  --wrong-dim: rgba(208, 48, 64, 0.1);
  --text: #2a2a3e;
  --text-dim: #6b6b80;
  --white: #1a1a2e;
  --safe-top: env(safe-area-inset-top, 0px);
  --safe-bottom: env(safe-area-inset-bottom, 0px);
}

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: 'Inter', -apple-system, sans-serif;
  font-size: 18px;
  overflow-x: hidden;
}

#app {
  max-width: 480px;
  margin: 0 auto;
  padding: 20px;
  padding-top: calc(48px + var(--safe-top));
  padding-bottom: calc(24px + var(--safe-bottom));
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}

.back-link {
  position: fixed; top: 12px; left: 12px;
  font-size: 13px; color: #6b6b80; text-decoration: none;
  letter-spacing: 1px; font-family: sans-serif; z-index: 999; padding: 8px;
}

.hidden { display: none !important; }

/* Title */
#title-screen {
  text-align: center; display: flex; flex-direction: column;
  align-items: center; justify-content: center; flex: 1;
  animation: fadeIn 0.5s ease-out;
}
.title-icon { font-size: 64px; margin-bottom: 12px; }
.game-title { font-size: 52px; font-weight: 900; letter-spacing: 6px; color: var(--accent); }
.tagline { font-size: 14px; letter-spacing: 3px; color: var(--text-dim); margin-top: 8px; }
.rules-box {
  margin: 32px 0; text-align: left; background: var(--card);
  border: 1.5px solid var(--card-border); border-radius: 12px;
  padding: 20px 24px; width: 100%;
}
.rules-box p { font-size: 16px; line-height: 1.8; color: var(--text); }
.hl { color: var(--accent); font-weight: 700; }
.best-score { font-size: 13px; color: var(--text-dim); margin-top: 12px; letter-spacing: 1px; }

/* Difficulty Picker */
.difficulty-picker {
  display: flex;
  gap: 8px;
  margin-bottom: 20px;
  width: 100%;
  max-width: 340px;
}
.diff-btn {
  flex: 1;
  background: var(--card);
  border: 2px solid var(--card-border);
  border-radius: 8px;
  padding: 12px 0;
  font-family: inherit;
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 2px;
  color: var(--text-dim);
  cursor: pointer;
  transition: all 0.15s;
}
.diff-btn:active { transform: scale(0.96); }
.diff-btn.active {
  border-color: var(--accent);
  background: var(--accent-dim);
  color: var(--accent);
}

/* Next Puzzle Countdown */
.next-puzzle-cd {
  font-size: 16px;
  font-weight: 700;
  letter-spacing: 2px;
  color: var(--accent);
  margin-top: 8px;
}
.next-puzzle-cd .cd-label {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 2px;
  color: var(--text-dim);
  display: block;
  margin-bottom: 6px;
}
.next-puzzle-cd .cd-time {
  font-size: 28px;
  font-weight: 900;
  color: var(--accent);
  letter-spacing: 3px;
  font-variant-numeric: tabular-nums;
}

/* Buttons */
.btn-main {
  background: var(--accent); color: #fff; font-family: inherit;
  font-size: 18px; font-weight: 800; letter-spacing: 2px; border: none;
  border-radius: 10px; padding: 0 32px; min-height: 58px; cursor: pointer;
  transition: all 0.15s; text-transform: uppercase; width: 100%; max-width: 340px;
}
.btn-main:active { transform: scale(0.97); opacity: 0.9; }
.btn-sm { min-height: 50px; max-width: 240px; margin: 0 auto; }

/* Game */
#game-screen {
  display: flex; flex-direction: column; flex: 1;
  animation: fadeIn 0.3s ease-out;
}
.game-header {
  display: flex; justify-content: space-between; align-items: center; margin-bottom: 8px;
}
.round-label { font-size: 14px; font-weight: 700; letter-spacing: 2px; color: var(--text-dim); }
.score-label { font-size: 22px; font-weight: 900; color: var(--accent); }

.progress-bar {
  height: 4px; background: var(--card-border); border-radius: 2px;
  margin-bottom: 20px; overflow: hidden; position: relative;
}
.progress-bar::after {
  content: ''; position: absolute; left: 0; top: 0; bottom: 0;
  width: var(--progress, 0%); background: var(--accent);
  border-radius: 2px; transition: width 0.3s ease;
}

.hint-label {
  font-size: 14px; font-weight: 600; letter-spacing: 2px;
  color: var(--text-dim); text-align: center; margin-bottom: 16px;
  text-transform: uppercase;
}

/* Letter Display */
.letter-display {
  display: flex; justify-content: center; gap: 8px;
  flex-wrap: wrap; margin-bottom: 32px; min-height: 80px;
  align-items: center;
}
.letter-box {
  width: 44px; height: 56px; border-radius: 8px;
  background: var(--card); border: 2px solid var(--card-border);
  display: flex; align-items: center; justify-content: center;
  font-family: 'JetBrains Mono', monospace; font-size: 26px; font-weight: 700;
  color: var(--white); transition: all 0.3s ease;
}
.letter-box.revealed {
  border-color: var(--accent);
  background: var(--accent-dim);
  animation: popIn 0.3s ease-out;
}
.letter-box.all-correct {
  border-color: var(--correct);
  background: var(--correct-dim);
  color: var(--correct);
}
.letter-box.all-wrong {
  border-color: var(--wrong);
  background: var(--wrong-dim);
  color: var(--wrong);
}

/* Guess Area */
.guess-area {
  display: flex; gap: 10px; margin-bottom: 20px;
}
.guess-input {
  flex: 1; background: var(--card); border: 2px solid var(--card-border);
  border-radius: 10px; padding: 0 18px; min-height: 56px;
  font-family: 'JetBrains Mono', monospace; font-size: 20px; font-weight: 700;
  color: var(--white); outline: none; letter-spacing: 2px;
  text-transform: uppercase;
}
.guess-input:focus { border-color: var(--accent); }
.guess-input::placeholder { color: var(--text-dim); font-size: 14px; letter-spacing: 1px; font-weight: 400; }

.btn-guess {
  background: var(--accent); color: #fff; border: none; border-radius: 10px;
  padding: 0 24px; min-height: 56px; font-family: inherit;
  font-size: 18px; font-weight: 800; letter-spacing: 1px; cursor: pointer;
  transition: all 0.15s;
}
.btn-guess:active { transform: scale(0.96); }

/* Feedback */
.feedback { text-align: center; animation: slideUp 0.3s ease-out; }
.feedback-text {
  font-size: 24px; font-weight: 800; letter-spacing: 2px; margin-bottom: 6px;
}
.feedback-text.correct { color: var(--correct); }
.feedback-text.wrong { color: var(--wrong); }
.feedback-word {
  font-family: 'JetBrains Mono', monospace; font-size: 20px;
  font-weight: 700; color: var(--white); letter-spacing: 3px; margin-bottom: 6px;
}
.feedback-pts { font-size: 15px; color: var(--text-dim); margin-bottom: 16px; }

/* Game Over */
#gameover-screen {
  text-align: center; display: flex; flex-direction: column;
  align-items: center; justify-content: center; flex: 1;
  animation: fadeIn 0.5s ease-out;
}
.gameover-heading { font-size: 32px; font-weight: 900; letter-spacing: 4px; color: var(--white); margin-bottom: 16px; }
.final-score { font-size: 64px; font-weight: 900; color: var(--accent); margin-bottom: 8px; }
.final-rank { font-size: 20px; font-weight: 700; color: var(--text); letter-spacing: 2px; margin-bottom: 24px; }
.final-stats { font-size: 15px; color: var(--text-dim); line-height: 2; margin-bottom: 32px; }

@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
@keyframes slideUp { from { opacity: 0; transform: translateY(16px); } to { opacity: 1; transform: translateY(0); } }
@keyframes popIn { from { transform: scale(0.6); opacity: 0; } to { transform: scale(1); opacity: 1; } }

@media (max-height: 667px) {
  .game-title { font-size: 40px; }
  .letter-box { width: 36px; height: 46px; font-size: 22px; }
  .rules-box { padding: 14px 18px; margin: 20px 0; }
}