:root {
  --bg: #0f1620;
  --panel: #1a2533;
  --panel-light: #233044;
  --accent: #4fd1c5;
  --accent-dark: #2ca39a;
  --text: #eef3f8;
  --text-dim: #9fb0c2;
  --correct: #4ade80;
  --incorrect: #f87171;

  --diff-1: #4ade80;
  --diff-2: #facc15;
  --diff-3: #fb923c;
  --diff-4: #f87171;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
}

#app {
  max-width: 1000px;
  margin: 0 auto;
  padding: 20px;
  min-height: 100vh;
}

.screen { display: none; }
.screen.active { display: block; }
.hidden { display: none !important; }

h1 {
  text-align: center;
  font-size: 2.2rem;
  margin-bottom: 4px;
  letter-spacing: 1px;
}

.subtitle {
  text-align: center;
  color: var(--text-dim);
  margin-top: 0;
  margin-bottom: 28px;
}

.setup-group {
  margin-bottom: 24px;
}

.setup-group h2 {
  font-size: 1.05rem;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-bottom: 10px;
  font-weight: 600;
}

.setup-group h2 .hint {
  text-transform: none;
  letter-spacing: normal;
  font-weight: 400;
  font-size: 0.85rem;
  opacity: 0.8;
}

.options-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}

.option-btn {
  background: var(--panel);
  border: 2px solid transparent;
  border-radius: 10px;
  padding: 14px 16px;
  text-align: left;
  cursor: pointer;
  color: var(--text);
  display: flex;
  flex-direction: column;
  gap: 4px;
  transition: border-color 0.15s, background 0.15s, transform 0.1s;
}

.option-btn:hover {
  background: var(--panel-light);
  transform: translateY(-1px);
}

.option-btn.selected {
  border-color: var(--accent);
  background: var(--panel-light);
}

#difficulty-options .option-btn[data-difficulty="1"] { border-color: color-mix(in srgb, var(--diff-1) 35%, transparent); }
#difficulty-options .option-btn[data-difficulty="2"] { border-color: color-mix(in srgb, var(--diff-2) 35%, transparent); }
#difficulty-options .option-btn[data-difficulty="3"] { border-color: color-mix(in srgb, var(--diff-3) 35%, transparent); }
#difficulty-options .option-btn[data-difficulty="4"] { border-color: color-mix(in srgb, var(--diff-4) 35%, transparent); }

#difficulty-options .option-btn[data-difficulty="1"].selected { border-color: var(--diff-1); box-shadow: 0 0 0 1px var(--diff-1) inset; }
#difficulty-options .option-btn[data-difficulty="2"].selected { border-color: var(--diff-2); box-shadow: 0 0 0 1px var(--diff-2) inset; }
#difficulty-options .option-btn[data-difficulty="3"].selected { border-color: var(--diff-3); box-shadow: 0 0 0 1px var(--diff-3) inset; }
#difficulty-options .option-btn[data-difficulty="4"].selected { border-color: var(--diff-4); box-shadow: 0 0 0 1px var(--diff-4) inset; }

.opt-title {
  font-weight: 700;
  font-size: 1.05rem;
}

.opt-desc {
  font-size: 0.82rem;
  color: var(--text-dim);
}

.primary-btn {
  display: block;
  width: 100%;
  margin-top: 8px;
  padding: 14px;
  font-size: 1.1rem;
  font-weight: 700;
  border: none;
  border-radius: 10px;
  background: var(--accent);
  color: #06231f;
  cursor: pointer;
  transition: background 0.15s, opacity 0.15s;
}

.primary-btn:hover:not(:disabled) {
  background: var(--accent-dark);
}

.primary-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.back-link { text-align: center; margin-top: 16px; font-size: 0.9rem; }
.back-link a { color: var(--muted); text-decoration: none; }
.back-link a:hover { color: var(--accent); }

.how-to {
  border: 1px solid var(--panel-light);
  border-radius: 8px;
  margin-top: 20px;
  background: var(--panel);
  max-width: 520px;
  width: 100%;
  text-align: left;
}

.how-to-summary {
  display: block;
  padding: 10px 14px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 1px;
  cursor: pointer;
  list-style: none;
  user-select: none;
}
.how-to-summary::-webkit-details-marker { display: none; }
.how-to-summary::before {
  content: "\25B8";
  display: inline-block;
  margin-right: 8px;
  transition: transform 0.2s;
}
details.how-to[open] > .how-to-summary::before { transform: rotate(90deg); }
.how-to-summary:hover { color: var(--text); }

.how-to-body { padding: 0 16px 12px; }
.how-to-body p {
  font-size: 0.9rem;
  color: var(--text-dim);
  line-height: 1.55;
  margin: 0 0 10px;
}
.how-to-body p:last-child { margin-bottom: 0; }
.how-to-body strong { color: var(--text); }

.text-btn {
  background: none;
  border: none;
  color: var(--text-dim);
  cursor: pointer;
  font-size: 0.95rem;
  text-decoration: underline;
}

.text-btn:hover { color: var(--text); }

/* ---------- Game screen ---------- */

.game-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

.hud {
  display: flex;
  gap: 18px;
  font-weight: 600;
  color: var(--text-dim);
}

#score-counter { color: var(--accent); }

.category-badge {
  text-align: center;
  margin-bottom: 16px;
  font-size: 0.9rem;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 1.5px;
  font-weight: 600;
}

.question-card {
  background: var(--panel);
  border-radius: 12px;
  border: 1px solid #233044;
  padding: 40px 32px;
  min-height: 120px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.question-text {
  font-size: 1.35rem;
  font-weight: 700;
  text-align: center;
  line-height: 1.5;
  margin: 0;
}

.feedback-banner {
  text-align: center;
  padding: 10px 22px;
  border-radius: 8px;
  font-weight: 700;
  font-size: 1.1rem;
  margin-top: 12px;
}

.feedback-banner.correct {
  background: var(--correct);
  color: #06270f;
}

.feedback-banner.incorrect {
  background: var(--incorrect);
  color: #2a0606;
}

.feedback-banner.hidden { display: none; }

.answers {
  margin-top: 18px;
}

.answer-btn {
  background: var(--panel);
  border: 2px solid transparent;
  border-radius: 10px;
  padding: 16px;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text);
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
  text-align: left;
}

.answer-btn:hover:not(:disabled) {
  background: var(--panel-light);
  border-color: var(--accent);
}

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

.answer-btn.correct {
  background: rgba(74, 222, 128, 0.18);
  border-color: var(--correct);
}

.answer-btn.incorrect {
  background: rgba(248, 113, 113, 0.18);
  border-color: var(--incorrect);
}

.final-score {
  text-align: center;
  font-size: 1.4rem;
  color: var(--accent);
  font-weight: 700;
}

.results-summary {
  margin: 24px 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.result-row {
  background: var(--panel);
  border-radius: 8px;
  padding: 12px 16px;
  display: flex;
  gap: 12px;
  align-items: flex-start;
  font-size: 0.92rem;
  line-height: 1.4;
}

.result-icon {
  flex-shrink: 0;
  font-size: 1.1rem;
  margin-top: 1px;
}

.result-question {
  color: var(--text-dim);
}

.result-answer {
  font-weight: 600;
}

.result-answer.correct { color: var(--correct); }
.result-answer.incorrect { color: var(--incorrect); }

.result-player {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  background: var(--accent);
  color: #fff;
  border-radius: 3px;
  padding: 1px 5px;
  margin-right: 4px;
  vertical-align: middle;
}

/* ---------- Format grid (4 columns on wide screens) ---------- */

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

/* ---------- True or False ---------- */

.tf-options { margin-top: 18px; }
.tf-options.hidden { display: none; }

.tf-proposed {
  background: var(--panel);
  border-radius: 10px;
  padding: 20px 24px;
  font-size: 1.15rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 14px;
  border: 1px solid var(--panel-light);
  color: var(--accent);
}

.tf-buttons {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.tf-btn {
  padding: 18px;
  font-size: 1.15rem;
  font-weight: 800;
  border-radius: 10px;
  border: 2px solid transparent;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
}

.tf-btn.true  { background: rgba(74,222,128,0.12);  color: var(--correct);   border-color: rgba(74,222,128,0.3); }
.tf-btn.false { background: rgba(248,113,113,0.12); color: var(--incorrect); border-color: rgba(248,113,113,0.3); }

.tf-btn.true:hover:not(:disabled)  { background: rgba(74,222,128,0.25);  border-color: var(--correct); }
.tf-btn.false:hover:not(:disabled) { background: rgba(248,113,113,0.25); border-color: var(--incorrect); }

.tf-btn:disabled { cursor: default; opacity: 0.7; }
.tf-btn.selected-correct { background: rgba(74,222,128,0.35);  border-color: var(--correct); }
.tf-btn.selected-wrong   { background: rgba(248,113,113,0.35); border-color: var(--incorrect); }

/* ---------- Type the answer ---------- */

.type-form { margin-top: 18px; display: flex; flex-direction: column; gap: 10px; }
.type-form.hidden { display: none; }

.type-input {
  width: 100%;
  padding: 16px 18px;
  font-size: 1.1rem;
  border-radius: 10px;
  border: 2px solid var(--panel-light);
  background: var(--panel);
  color: var(--text);
  font-family: inherit;
  transition: border-color 0.2s, background 0.2s;
}

.type-input:focus { outline: none; border-color: var(--accent); }
.type-input.correct   { background: rgba(74,222,128,0.12);  border-color: var(--correct); }
.type-input.incorrect { background: rgba(248,113,113,0.12); border-color: var(--incorrect); }

.type-submit { margin-top: 0; }

/* ---------- Add question button ---------- */

.add-q-btn {
  position: fixed;
  bottom: 20px;
  right: 20px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 2px solid var(--panel-light);
  background: var(--panel);
  font-size: 1.2rem;
  cursor: pointer;
  color: var(--text-dim);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: border-color 0.15s, color 0.15s;
  z-index: 100;
}

.add-q-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* ---------- Add question form ---------- */

.aq-input {
  width: 100%;
  padding: 12px 14px;
  font-size: 1rem;
  border-radius: 10px;
  border: 2px solid var(--panel-light);
  background: var(--panel);
  color: var(--text);
  font-family: inherit;
  transition: border-color 0.2s;
}

.aq-input:focus {
  outline: none;
  border-color: var(--accent);
}

.aq-textarea {
  min-height: 90px;
  resize: vertical;
}

.aq-mt { margin-top: 8px; }

.aq-feedback {
  padding: 10px 16px;
  border-radius: 8px;
  font-weight: 700;
  margin-bottom: 8px;
}

.aq-feedback.success { background: rgba(74,222,128,0.18); color: var(--correct); border: 1px solid var(--correct); }
.aq-feedback.error   { background: rgba(248,113,113,0.18); color: var(--incorrect); border: 1px solid var(--incorrect); }
.aq-feedback.hidden  { display: none; }

.aq-buttons {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 28px;
}

.aq-saved-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 12px;
}

.aq-saved-item {
  background: var(--panel);
  border-radius: 8px;
  padding: 10px 14px;
  font-size: 0.88rem;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 10px;
}

.aq-saved-item-text { color: var(--text-dim); flex: 1; }
.aq-saved-item-text strong { color: var(--text); }

.aq-delete-btn {
  background: none;
  border: none;
  color: var(--incorrect);
  cursor: pointer;
  font-size: 1rem;
  flex-shrink: 0;
  padding: 0 4px;
}

.aq-clear-btn {
  background: none;
  border: 1px solid var(--incorrect);
  color: var(--incorrect);
  border-radius: 8px;
  padding: 8px 16px;
  cursor: pointer;
  font-size: 0.88rem;
  width: 100%;
  transition: background 0.15s;
}

.aq-clear-btn:hover { background: rgba(248,113,113,0.1); }

@media (max-width: 600px) {
  .options-grid { grid-template-columns: 1fr; }
  .answers { grid-template-columns: 1fr; }
  h1 { font-size: 1.6rem; }
  .question-text { font-size: 1.15rem; }
  .question-card { padding: 28px 20px; min-height: 100px; }
}