:root {
  --ink: #1B1F2A;
  --ink-raised: #232838;
  --paper: #E4E7E2;
  --paper-dim: #C9CEC5;
  --rail: #556273;
  --accent: #C98A3E;
  --accent-dim: #8C6431;
  --success: #4F7A5B;
  --success-bg: #24312A;
  --error: #C1725D;
  --text-hi: #F2F1EC;
  --text-lo: #9AA1AC;
  --font-display: 'Space Grotesk', sans-serif;
  --font-body: 'Inter', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
  --radius: 10px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--ink);
  color: var(--text-hi);
  font-family: var(--font-body);
  -webkit-font-smoothing: antialiased;
}

body:focus-visible, button:focus-visible, input:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.app {
  max-width: 420px;
  margin: 0 auto;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  padding: 0 20px;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 0 8px;
}

.brand { display: flex; align-items: center; gap: 8px; color: var(--text-hi); }
.brand-mark { color: var(--accent); display: flex; }
.brand-name { font-family: var(--font-display); font-weight: 600; font-size: 20px; letter-spacing: 0.02em; }

.topbar-actions { display: flex; align-items: center; gap: 8px; }

.icon-btn {
  width: 40px; height: 40px;
  border-radius: 50%;
  border: 1px solid var(--rail);
  background: transparent;
  color: var(--text-lo);
  font-family: var(--font-body);
  font-weight: 500;
  cursor: pointer;
}
.icon-btn:hover { border-color: var(--text-lo); color: var(--text-hi); }

main { flex: 1; padding-bottom: 24px; }

/* --- Mode tabs & difficulty --- */
.mode-tabs {
  display: flex;
  gap: 6px;
  margin-top: 14px;
  border-bottom: 1px solid var(--ink-raised);
}
.tab-btn {
  background: transparent;
  color: var(--text-lo);
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 14px;
  min-height: 44px;
  padding: 8px 12px 10px;
  border-bottom: 2px solid transparent;
  border-radius: 0;
}
.tab-btn[aria-selected="true"] {
  color: var(--text-hi);
  border-bottom-color: var(--accent);
}

.difficulty-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 14px;
}
.diff-btn {
  height: 40px;
  padding: 0 14px;
  background: transparent;
  border: 1px solid var(--rail);
  color: var(--text-lo);
  font-size: 13px;
}
.diff-btn.is-active {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--ink);
}
.difficulty-row .icon-btn {
  margin-left: auto;
}
.difficulty-row[hidden] {
  display: none;
}

.puzzle-meta {
  font-size: 13px;
  color: var(--text-lo);
  margin: 12px 0 20px;
}
.puzzle-meta .dot { margin: 0 6px; }

/* --- The ladder --- */
.ladder {
  position: relative;
  padding-left: 28px;
  margin-bottom: 20px;
  min-height: 60px;
}
.ladder::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 8px;
  bottom: 8px;
  width: 3px;
  background: var(--rail);
  border-radius: 2px;
}

.rung {
  position: relative;
  display: flex;
  align-items: center;
  gap: 5px;
  margin-bottom: 10px;
}
.rung::before {
  content: "";
  position: absolute;
  left: -22px;
  top: 50%;
  width: 16px;
  height: 3px;
  background: var(--rail);
  transform: translateY(-50%);
}
.rung.is-goal::before,
.rung.is-solved::before { background: var(--accent); }

.tile {
  width: 34px;
  height: 34px;
  border-radius: 6px;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.rung.is-start .tile { background: var(--paper-dim); }
.rung.is-goal .tile {
  background: transparent;
  border: 2px dashed var(--rail);
  color: var(--text-lo);
}
.rung.is-solved .tile {
  background: var(--accent);
  color: var(--ink);
}
.rung.is-latest .tile { background: var(--paper); }

.tile.is-hint-letter {
  box-shadow: 0 0 0 2px var(--accent);
  animation: hint-pulse 1.4s ease-in-out infinite;
}
@keyframes hint-pulse {
  0%, 100% { box-shadow: 0 0 0 2px var(--accent); }
  50% { box-shadow: 0 0 0 4px var(--accent); }
}

.rung-tag {
  font-size: 12px;
  color: var(--text-lo);
  margin-left: 6px;
}
.rung.is-solved .rung-tag { color: var(--success); }

/* --- Input --- */
.input-row {
  display: flex;
  gap: 8px;
  margin-bottom: 10px;
}
.input-row[hidden] {
  display: none;
}
#guessInput {
  flex: 1;
  height: 44px;
  border-radius: var(--radius);
  border: 1px solid var(--rail);
  background: var(--ink-raised);
  color: var(--text-hi);
  font-family: var(--font-mono);
  font-size: 16px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 0 14px;
}
#guessInput::placeholder { color: var(--text-lo); text-transform: none; letter-spacing: normal; font-family: var(--font-body); }

button {
  font-family: var(--font-body);
  font-weight: 500;
  font-size: 14px;
  cursor: pointer;
  border-radius: var(--radius);
  border: none;
}
#submitBtn {
  height: 44px;
  padding: 0 20px;
  background: var(--accent);
  color: var(--ink);
}
#submitBtn:hover { background: #d99b52; }
#submitBtn:active { transform: scale(0.98); }

.play-again-btn {
  display: block;
  width: 100%;
  height: 44px;
  margin-bottom: 10px;
  background: var(--accent);
  color: var(--ink);
  font-weight: 500;
}
.play-again-btn:hover { background: #d99b52; }
.play-again-btn:active { transform: scale(0.98); }
.play-again-btn[hidden] {
  display: none;
}

.hint-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 10px;
}
.hint-row[hidden] {
  display: none;
}
.hint-btn {
  height: 36px;
  padding: 0 14px;
  background: transparent;
  border: 1px solid var(--rail);
  color: var(--text-lo);
  font-size: 13px;
}
.hint-btn:hover:not(:disabled) { border-color: var(--text-lo); color: var(--text-hi); }
.hint-btn:disabled { opacity: 0.5; cursor: default; }
.hint-count {
  font-size: 12px;
  color: var(--text-lo);
}

.feedback {
  min-height: 18px;
  font-size: 13px;
  color: var(--error);
  margin: 0 0 16px;
}

.win-card {
  background: var(--success-bg);
  border-radius: 14px;
  padding: 18px;
  text-align: center;
}
@keyframes win-pop {
  0% { transform: scale(0.9); opacity: 0; }
  60% { transform: scale(1.03); opacity: 1; }
  100% { transform: scale(1); opacity: 1; }
}
.win-card.is-popping { animation: win-pop 0.4s ease-out; }
.win-title { font-family: var(--font-display); font-size: 18px; font-weight: 600; margin: 0 0 4px; color: var(--text-hi); }
.win-detail { font-size: 13px; color: var(--text-lo); margin: 0 0 14px; }
.next-puzzle-note { font-size: 12px; color: var(--text-lo); margin: -8px 0 14px; }
.win-actions { display: flex; gap: 8px; justify-content: center; flex-wrap: wrap; }
.win-actions button {
  height: 38px;
  padding: 0 16px;
  background: var(--accent);
  color: var(--ink);
}
.win-actions button.ghost {
  background: transparent;
  border: 1px solid var(--rail);
  color: var(--text-lo);
}

.foot {
  padding: 14px 0 24px;
  font-size: 12px;
  color: var(--text-lo);
  text-align: center;
  border-top: 1px solid var(--ink-raised);
}

/* --- Help modal --- */
.modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,0.55);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}
.modal-backdrop[hidden] {
  display: none;
}
.modal {
  background: var(--ink-raised);
  border-radius: 14px;
  padding: 22px;
  max-width: 340px;
  border: 1px solid var(--rail);
}
.help-text { font-size: 14px; line-height: 1.6; color: var(--text-lo); margin: 0 0 14px; }
.help-text:last-of-type { margin-bottom: 18px; }
#closeHelp { height: 38px; padding: 0 18px; background: var(--accent); color: var(--ink); width: 100%; }

.modal-input {
  width: 100%;
  height: 40px;
  border-radius: var(--radius);
  border: 1px solid var(--rail);
  background: var(--ink);
  color: var(--text-hi);
  font-family: var(--font-body);
  font-size: 14px;
  padding: 0 12px;
  margin-bottom: 14px;
}

.lb-list {
  list-style: none;
  margin: 0 0 14px;
  padding: 0;
  max-height: 220px;
  overflow-y: auto;
}
.lb-list li {
  font-size: 14px;
  color: var(--text-hi);
  padding: 6px 0;
  border-bottom: 1px solid var(--ink);
}
.lb-list li:last-child { border-bottom: none; }

@media (max-width: 360px) {
  .tile { width: 30px; height: 30px; font-size: 14px; }
}