:root {
  --bg: #eef3f1;
  --card: #ffffff;
  --panel: rgba(255, 255, 255, 0.94);
  --subtle: #f5f8f7;
  --control: #eef4f2;
  --answer: #f7faf9;
  --border: rgba(23, 33, 31, 0.1);
  --text: #17211f;
  --muted: #66736f;
  --accent: #256f68;
  --accent-soft: #dcefeb;
  --success: #21835b;
  --danger: #c74638;
  --warning: #c78321;
  --hint-text: #5f4209;
  --hint-bg: #fff3d8;
  --correct-bg: #dff3e9;
  --correct-text: #114d35;
  --wrong-bg: #fde4df;
  --wrong-text: #76231b;
  --feedback-correct: #e2f5eb;
  --feedback-wrong: #fff0dd;
  --shadow: 0 18px 45px rgba(25, 43, 38, 0.14);
  --radius: 8px;
}

body.dark-theme,
:root.dark-theme {
  --bg: #101615;
  --card: #18211f;
  --panel: rgba(24, 33, 31, 0.96);
  --subtle: #202c29;
  --control: #22312e;
  --answer: #1f2b28;
  --border: rgba(220, 239, 235, 0.16);
  --text: #eef7f4;
  --muted: #aab9b5;
  --accent: #62c7b8;
  --accent-soft: #1e3f3a;
  --success: #62c78f;
  --danger: #ee796b;
  --warning: #e2a94d;
  --hint-text: #ffe1a1;
  --hint-bg: #3a2b12;
  --correct-bg: #163c2c;
  --correct-text: #d9f8e8;
  --wrong-bg: #48221f;
  --wrong-text: #ffe1dc;
  --feedback-correct: #183d2d;
  --feedback-wrong: #3b2a16;
  --shadow: 0 18px 45px rgba(0, 0, 0, 0.32);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    linear-gradient(135deg, rgba(37, 111, 104, 0.12), transparent 34%),
    linear-gradient(315deg, rgba(199, 131, 33, 0.14), transparent 30%),
    var(--bg);
  color: var(--text);
  font-family: Arial, Helvetica, sans-serif;
}

button {
  font: inherit;
}

.app-shell {
  width: min(1120px, calc(100% - 28px));
  margin: 0 auto;
  padding: 22px 0 36px;
}

.credits-top {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 8px;
  margin-bottom: 16px;
  color: var(--muted);
  font-size: 0.88rem;
  font-weight: 800;
}

.credits-top a {
  color: var(--accent);
  text-decoration: none;
}

.credits-top a:hover {
  text-decoration: underline;
}

.credits-separator {
  color: var(--muted);
  opacity: 0.55;
}

.controls-disclosure,
.control-band,
.context-block,
.task-card,
.game-over,
.weak-spots,
.cheat-sheet {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.app-title p {
  margin: 0 0 3px;
  color: var(--accent);
  font-size: clamp(1.35rem, 3vw, 2.1rem);
  font-weight: 900;
  line-height: 1.1;
  text-transform: uppercase;
}

.app-title span {
  display: block;
  color: var(--muted);
  font-size: 0.9rem;
  font-weight: 700;
}

.theme-toggle {
  margin-top: 10px;
  min-height: 40px;
  padding: 0 14px;
  color: var(--text);
  background: var(--control);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  cursor: pointer;
  font-weight: 800;
}

h2,
p {
  margin-top: 0;
}

main {
  display: grid;
  gap: 12px;
  margin-top: 12px;
}

.controls-disclosure {
  overflow: hidden;
}

.controls-disclosure summary {
  display: none;
}

.control-band {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 18px;
  padding: 18px;
  background: transparent;
  border: 0;
  box-shadow: none;
}

.control-band h2,
.context-block h2,
.weak-spots h2 {
  font-size: 1rem;
  margin-bottom: 10px;
  color: var(--muted);
}

.context-block {
  display: grid;
  grid-template-columns: minmax(180px, 0.65fr) 1fr;
  gap: 12px;
  align-items: center;
  padding: 14px;
}

.context-block p {
  margin: 0;
  color: var(--muted);
  font-weight: 700;
}

.context-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 8px;
}

.context-grid button {
  min-height: 42px;
  padding: 0 10px;
  color: var(--text);
  background: var(--control);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  cursor: pointer;
  font-weight: 800;
}

.button-row,
.level-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 9px;
}

.level-grid {
  display: grid;
  grid-template-columns: repeat(8, minmax(44px, 1fr));
}

.primary-button,
.secondary-button,
.ghost-button,
.mode-button,
.level-button,
.answer-button {
  min-height: 44px;
  border: 0;
  border-radius: var(--radius);
  cursor: pointer;
  transition: transform 0.15s ease, background 0.15s ease, border 0.15s ease;
}

.primary-button {
  background: var(--accent);
  color: white;
  padding: 0 22px;
  font-weight: 700;
}

.secondary-button,
.mode-button,
.level-button,
.ghost-button {
  background: var(--control);
  color: var(--text);
  border: 1px solid var(--border);
  padding: 0 14px;
  font-weight: 700;
}

.mode-button.active,
.level-button.active {
  background: var(--accent);
  color: white;
}

.level-button.locked {
  color: var(--text);
  background: var(--control);
}

.level-button.active,
.level-button.locked.active {
  background: var(--accent);
  color: white;
}

.level-description {
  margin: 10px 0 0;
  color: var(--muted);
  font-weight: 700;
  line-height: 1.4;
}

.primary-button:active,
.secondary-button:active,
.ghost-button:active,
.mode-button:active,
.level-button:active,
.answer-button:active {
  transform: scale(0.98);
}

.timer-box {
  color: white;
  background: var(--warning);
  padding: 8px 10px;
  border-radius: var(--radius);
}

.task-card {
  padding: 24px;
}

.task-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 10px;
  color: var(--muted);
  font-weight: 800;
  font-size: 0.92rem;
}

.task-stats span {
  padding: 5px 9px;
  background: var(--subtle);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.task-stats strong {
  color: var(--text);
}

.task-stats span:nth-child(3) strong {
  color: var(--danger);
}

.heart-stat {
  letter-spacing: 0;
}

.task-header {
  display: flex;
  justify-content: space-between;
  gap: 8px;
  align-items: flex-start;
}

.nano-context {
  display: inline-block;
  margin: 0 0 6px;
  padding: 5px 8px;
  color: var(--muted);
  background: var(--subtle);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 0.92rem;
  font-weight: 800;
}

#originalSentence {
  font-size: clamp(2rem, 5vw, 4.2rem);
  line-height: 1.1;
  margin-bottom: 0;
}

.translation {
  color: var(--muted);
  font-size: 1.08rem;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  align-content: flex-start;
  justify-content: flex-end;
  gap: 4px;
  max-width: 360px;
  margin: 2px 0 0;
}

.tag {
  position: relative;
  color: var(--accent);
  background:
    linear-gradient(135deg, rgba(91, 197, 179, 0.24), rgba(91, 197, 179, 0.08)),
    var(--accent-soft);
  border: 1px solid rgba(91, 197, 179, 0.28);
  border-radius: 999px;
  padding: 5px 9px;
  font-size: 0.78rem;
  font-weight: 700;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.16);
  cursor: pointer;
}

.tag:hover,
.tag:focus-visible {
  color: var(--text);
  border-color: var(--accent);
  transform: translateY(-1px);
}

.tag:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
}

.hint-box {
  margin: 8px 0 0;
  padding: 12px;
  color: var(--hint-text);
  background: var(--hint-bg);
  border: 1px solid rgba(199, 131, 33, 0.35);
  border-radius: var(--radius);
  font-weight: 700;
}

.hint-button {
  margin-top: 14px;
}

.answers-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 10px;
}

.answer-button {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 10px;
  text-align: center;
  color: var(--text);
  background: var(--answer);
  border: 2px solid var(--border);
  padding: 14px 18px;
  font-size: clamp(1.05rem, 2vw, 1.35rem);
  font-weight: 700;
}

.answer-button::after {
  content: "";
}

.answer-letter {
  color: var(--muted);
  opacity: 0.58;
  font-weight: 900;
}

.answer-button.correct {
  background: var(--correct-bg);
  border-color: var(--success);
  color: var(--correct-text);
}

.answer-button.wrong {
  background: var(--wrong-bg);
  border-color: var(--danger);
  color: var(--wrong-text);
}

.answer-button:disabled {
  cursor: default;
}

.feedback-panel {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 16px;
  align-items: end;
  margin-top: 18px;
  padding: 16px;
  border-radius: var(--radius);
}

.feedback-panel.correct {
  background: var(--feedback-correct);
  border: 1px solid rgba(33, 131, 91, 0.25);
}

.feedback-panel.wrong {
  background: var(--feedback-wrong);
  border: 1px solid rgba(199, 70, 56, 0.25);
}

.feedback-title {
  font-size: 1.35rem;
  font-weight: 800;
  margin-bottom: 6px;
}

.correct-answer {
  font-weight: 800;
  margin-bottom: 8px;
}

.explanation {
  color: var(--text);
  margin-bottom: 10px;
}

.case-logic {
  margin: 0;
  padding-left: 18px;
  color: var(--muted);
}

.game-over {
  padding: 22px;
  border-left: 6px solid var(--danger);
}

.bottom-tools {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.weak-spots,
.cheat-sheet {
  padding: 18px;
}

.weak-spot-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  color: var(--muted);
}

.weak-chip {
  background: var(--control);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 8px 11px;
  font-weight: 700;
}

.cheat-sheet summary {
  cursor: pointer;
  font-weight: 800;
  font-size: 1.1rem;
}

.cheat-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin-top: 16px;
}

.cheat-block {
  background: var(--subtle);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 13px;
}

.cheat-block h3 {
  margin: 0 0 8px;
  color: var(--accent);
}

.cheat-block p {
  margin-bottom: 0;
  line-height: 1.5;
}

.note-list {
  margin: 14px 0 0;
  color: var(--muted);
  line-height: 1.55;
}

.hidden {
  display: none !important;
}

.help-tooltip {
  position: fixed;
  z-index: 40;
  max-width: 260px;
  padding: 9px 11px;
  color: var(--text);
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  font-size: 0.9rem;
  font-weight: 700;
  line-height: 1.35;
  pointer-events: none;
}

.help-dialog {
  position: fixed;
  inset: 0;
  z-index: 50;
  display: grid;
  place-items: center;
  padding: 18px;
  background: rgba(0, 0, 0, 0.45);
}

.help-dialog-card {
  width: min(360px, 100%);
  padding: 18px;
  color: var(--text);
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.help-dialog-card h2 {
  margin-bottom: 8px;
  color: var(--accent);
}

.help-dialog-card p {
  color: var(--muted);
  font-weight: 700;
  line-height: 1.45;
}

@media (max-width: 820px) {
  .app-shell {
    padding-top: 8px;
    padding-bottom: 132px;
  }

  main {
    gap: 10px;
    margin-top: 10px;
  }

  .task-header,
  .feedback-panel {
    grid-template-columns: 1fr;
    flex-direction: column;
    align-items: stretch;
  }

  .control-band,
  .context-block,
  .answers-grid,
  .cheat-grid {
    grid-template-columns: 1fr;
  }

  .theme-toggle {
    min-height: 38px;
    margin-top: 8px;
  }

  .controls-disclosure summary {
    display: flex;
    align-items: center;
    justify-content: space-between;
    min-height: 44px;
    padding: 0 14px;
    color: var(--text);
    background: var(--control);
    border-radius: var(--radius);
    cursor: pointer;
    font-weight: 800;
  }

  .controls-disclosure summary::after {
    content: "+";
    color: var(--accent);
    font-size: 1.4rem;
  }

  .controls-disclosure[open] summary::after {
    content: "-";
  }

  .control-band {
    padding: 12px;
    gap: 12px;
  }

  .context-block {
    padding: 12px;
    gap: 8px;
  }

  .context-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .level-grid {
    grid-template-columns: repeat(4, 1fr);
  }

  .task-card {
    padding: 14px;
  }

  .task-stats {
    justify-content: space-between;
    margin-bottom: 8px;
  }

  .task-stats span {
    flex: 1;
    padding: 5px 8px;
  }

  .timer-box {
    flex: 0 0 auto;
  }

  #originalSentence {
    font-size: clamp(1.7rem, 8vw, 2.45rem);
    margin-bottom: 4px;
  }

  .tag {
    padding: 3px 6px;
  }

  .answers-grid {
    gap: 8px;
    margin-top: 8px;
  }

  .hint-button {
    margin-top: 12px;
  }

  .tag-list {
    justify-content: flex-start;
    max-width: none;
  }

  .feedback-panel {
    display: grid;
    position: fixed;
    left: 9px;
    right: 9px;
    bottom: 9px;
    z-index: 20;
    max-height: 44vh;
    overflow: auto;
    box-shadow: var(--shadow);
  }
}

@media (max-width: 520px) {
  .app-shell {
    width: min(100% - 18px, 1120px);
    padding-top: 9px;
  }

  .control-band,
  .context-block,
  .task-card,
  .weak-spots,
  .cheat-sheet {
    padding: 14px;
  }

  .answer-button {
    min-height: 50px;
    padding: 9px 12px;
  }
}