:root {
  --bg:         #0f1923;
  --bg-card:    #1a2634;
  --bg-hover:   #243040;
  --accent:     #ff4655;
  --accent-dim: #c73040;
  --correct:    #00c89c;
  --wrong:      #ff4655;
  --text:       #ece8e1;
  --text-muted: #7a8a99;
  --border:     #ffffff12;
  --radius:     10px;
  --transition: 0.18s ease;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: 'Noto Sans JP', sans-serif;
  -webkit-font-smoothing: antialiased;
  overscroll-behavior: none;
}

.screen {
  display: none;
  position: fixed;
  inset: 0;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}
.screen.active { display: flex; }

#screen-loading {
  gap: 20px;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.spinner {
  width: 40px;
  height: 40px;
  border: 3px solid #ffffff15;
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

.start-inner,
.result-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  padding: 40px 24px;
  text-align: center;
  max-width: 400px;
  width: 100%;
}

.start-inner .btn-home,
.result-inner .btn-home {
  align-self: flex-start;
}

.label {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.15em;
}

h1 {
  font-size: 1.8rem;
  font-weight: 700;
  letter-spacing: 0.04em;
}

h2 {
  font-size: 1.6rem;
  font-weight: 700;
}

.desc {
  color: var(--text-muted);
  font-size: 0.88rem;
  line-height: 1.7;
}

.btn-primary {
  margin-top: 8px;
  padding: 14px 48px;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  font-family: inherit;
  transition: background var(--transition), transform var(--transition);
  letter-spacing: 0.06em;
}
.btn-primary:hover  { background: var(--accent-dim); }
.btn-primary:active { transform: scale(0.96); }

.result-score {
  display: flex;
  align-items: baseline;
  gap: 4px;
}
#result-num {
  font-size: 3.5rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
}
.result-denom {
  font-size: 1rem;
  color: var(--text-muted);
}
.result-msg {
  font-size: 1rem;
  color: var(--text-muted);
  min-height: 1.5em;
}

/* ── Quiz screen ── */
#screen-quiz {
  display: none;
  flex-direction: column;
  align-items: stretch;
  justify-content: flex-start;
  overflow: hidden;
}
#screen-quiz.active { display: flex; }

.quiz-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 20px;
  background: #0d1520;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}
.quiz-meta {
  display: flex;
  gap: 16px;
  font-size: 0.85rem;
  color: var(--text-muted);
}
#q-score {
  font-weight: 700;
  color: var(--text);
}

.btn-home {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.78rem;
  font-weight: 600;
  padding: 5px 10px;
  border: 1.5px solid #ffffff20;
  border-radius: 6px;
  transition: color var(--transition), border-color var(--transition);
  white-space: nowrap;
  flex-shrink: 0;
}
.btn-home:hover {
  color: var(--text);
  border-color: #ffffff50;
}

/* 上半分: スクロール可能な画像エリア */
.quiz-image-area {
  flex: 1;
  min-height: 0;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 12px 16px;
}

.card-image-wrap {
  width: 160px;
  background: var(--bg-card);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}

#card-image {
  width: 100%;
  height: auto;
  display: block;
  user-select: none;
  -webkit-user-drag: none;
}

/* 下半分: 固定のコントロールエリア */
.quiz-controls {
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  padding: 12px 16px 24px;
  border-top: 1px solid var(--border);
  background: var(--bg);
  width: 100%;
}

.choices {
  width: 100%;
  max-width: 480px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.choice-btn {
  padding: 14px 10px;
  background: var(--bg-card);
  color: var(--text);
  border: 1.5px solid var(--border);
  border-radius: var(--radius);
  font-size: 0.82rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  text-align: center;
  line-height: 1.4;
  transition: background var(--transition), border-color var(--transition), transform var(--transition);
  word-break: break-all;
}
.choice-btn:hover:not(:disabled) {
  background: var(--bg-hover);
  border-color: #ffffff30;
}
.choice-btn:active:not(:disabled) { transform: scale(0.97); }

.feedback {
  display: none;
  width: 100%;
  max-width: 480px;
  padding: 12px 16px;
  border-radius: var(--radius);
  text-align: center;
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.5;
}
.feedback.correct {
  display: block;
  background: rgba(0, 200, 156, 0.15);
  border: 1.5px solid var(--correct);
  color: var(--correct);
}
.feedback.wrong {
  display: block;
  background: rgba(255, 70, 85, 0.12);
  border: 1.5px solid var(--wrong);
  color: var(--wrong);
}

.choice-btn.selected {
  background: rgba(255, 70, 85, 0.12);
  border-color: var(--accent);
  color: var(--text);
}
.choice-btn.correct {
  background: rgba(0, 200, 156, 0.15);
  border-color: var(--correct);
  color: var(--correct);
}
.choice-btn.wrong {
  background: rgba(255, 70, 85, 0.12);
  border-color: var(--wrong);
  color: var(--wrong);
  opacity: 0.6;
}
.choice-btn:disabled { cursor: default; }

#btn-answer {
  width: 100%;
  max-width: 480px;
  padding: 14px;
  background: var(--accent);
  color: #fff;
  border: 1.5px solid transparent;
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-weight: 700;
  font-family: inherit;
  cursor: pointer;
  transition: background var(--transition), opacity var(--transition);
  letter-spacing: 0.04em;
}
#btn-answer:hover:not(:disabled) { background: var(--accent-dim); }
#btn-answer:disabled {
  background: var(--bg-card);
  color: var(--text-muted);
  border-color: var(--border);
  cursor: default;
}
#btn-answer.hidden { display: none; }

#btn-next {
  width: 100%;
  max-width: 480px;
  padding: 14px;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-weight: 700;
  font-family: inherit;
  cursor: pointer;
  display: none;
  transition: background var(--transition);
  letter-spacing: 0.04em;
}
#btn-next:hover   { background: var(--accent-dim); }
#btn-next.visible { display: block; }

@media (max-width: 400px) {
  .choices { grid-template-columns: 1fr; }
  .choice-btn { font-size: 0.78rem; }
  h1 { font-size: 1.5rem; }
}