:root {
  --bg: #0f172a;
  --panel: #1e293b;
  --accent: #38bdf8;
  --good: #4ade80;
  --bad: #f87171;
  --text: #e2e8f0;
  --muted: #94a3b8;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Yu Gothic", sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

.screen { display: none; padding: 20px; max-width: 480px; margin: 0 auto; }
.screen.active { display: block; }

h1 { font-size: 20px; text-align: center; margin-bottom: 4px; }
.sub { text-align: center; color: var(--muted); font-size: 13px; margin-bottom: 20px; }

.card {
  background: var(--panel);
  border-radius: 12px;
  padding: 16px;
  margin-bottom: 16px;
}

label { display: block; font-size: 13px; color: var(--muted); margin: 10px 0 4px; }
summary { font-size: 13px; color: var(--text); cursor: pointer; user-select: none; }
summary::marker { color: var(--muted); }
details .hint { text-align: left; margin-top: 10px; }
details .hint strong { color: var(--text); }
input[type="text"], input[type="number"], select {
  width: 100%;
  padding: 10px;
  border-radius: 8px;
  border: 1px solid #334155;
  background: #0b1220;
  color: var(--text);
  font-size: 16px;
}

button {
  width: 100%;
  padding: 12px;
  border: none;
  border-radius: 8px;
  background: var(--accent);
  color: #06202f;
  font-weight: bold;
  font-size: 15px;
  margin-top: 10px;
  cursor: pointer;
}
button.secondary { background: #334155; color: var(--text); }
button:disabled { opacity: 0.5; cursor: default; }

.level-badge {
  display: inline-block;
  background: var(--accent);
  color: #06202f;
  font-weight: bold;
  padding: 4px 12px;
  border-radius: 999px;
  font-size: 14px;
}

.flash-area {
  height: 220px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 64px;
  font-weight: bold;
  background: #0b1220;
  border-radius: 12px;
  margin-bottom: 16px;
}
.flash-area.plus { color: var(--good); }
.flash-area.minus { color: var(--bad); }
.flash-area.expr { color: var(--accent); font-size: 48px; }
.flash-area.start-cue { color: var(--accent); font-size: 44px; }

.answer-input {
  font-size: 28px;
  text-align: center;
  letter-spacing: 2px;
}

.status-line { text-align: center; font-size: 15px; margin-top: 10px; min-height: 22px; }
.status-line.correct { color: var(--good); }
.status-line.incorrect { color: var(--bad); }
.status-line.pending { color: var(--muted); }

.mode-toggle { display: flex; gap: 8px; }
.mode-toggle button { flex: 1; margin-top: 0; }
.mode-toggle button.active { background: var(--accent); }
.mode-toggle button.inactive { background: #334155; color: var(--text); }

.result-summary { text-align: center; }
.result-summary .big { font-size: 40px; font-weight: bold; margin: 10px 0; }
.result-summary .pass { color: var(--good); }
.result-summary .fail { color: var(--bad); }

.hint { font-size: 12px; color: var(--muted); text-align: center; margin-top: 8px; }

/* アプリ専用の数字キーパッド(端末標準キーボードの出現/消失によるガタつきを避けるため) */
.numpad {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  margin-top: 14px;
}
.numpad button {
  margin-top: 0;
  height: 52px;
  font-size: 20px;
  background: #334155;
  color: var(--text);
  font-weight: normal;
}
.numpad button:active { background: #475569; }
.numpad button.numpad-minus { color: #fbbf24; }
.numpad button.numpad-backspace { color: var(--bad); font-size: 18px; }
.numpad.hidden { display: none; }

/* 正答時の花火演出(canvas) */
#firework-canvas {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 998;
  display: none;
}

/* 中央に大きく出す演出バナー(正解/骸骨/次の問題で共用) */
.center-banner {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%) scale(0.4);
  font-weight: 900;
  text-align: center;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  z-index: 1000;
  transition: transform 350ms cubic-bezier(.34, 1.56, .64, 1), opacity 250ms ease;
}
.center-banner.show {
  opacity: 1;
  visibility: visible;
  transform: translate(-50%, -50%) scale(1);
}
.correct-banner {
  font-size: 56px;
  color: #ffd166;
  text-shadow: 0 0 14px rgba(255, 209, 102, 0.9), 0 0 28px rgba(255, 209, 102, 0.5);
}
.skull-banner {
  font-size: 76px;
  color: #f87171;
  text-shadow: 0 0 14px rgba(248, 113, 113, 0.9), 0 0 28px rgba(248, 113, 113, 0.5);
}
.next-banner {
  font-size: 32px;
  color: #38bdf8;
  text-shadow: 0 0 10px rgba(56, 189, 248, 0.7);
}

.play-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}
.play-header h1 { margin: 0; }
.quit-btn {
  width: auto;
  padding: 8px 14px;
  font-size: 13px;
  margin-top: 0;
  background: #334155;
  color: var(--text);
}

/* ホーム画面の技能一覧(加算/減算/掛け算/割り算) */
.skill-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
}
.skill-row-label { font-size: 15px; font-weight: bold; flex: 1 1 auto; }
.skill-row-level { flex: 0 0 auto; }
.skill-row-actions {
  flex: 1 0 100%;
  display: flex;
  gap: 8px;
}
.skill-row-actions button { flex: 1; margin-top: 0; padding: 8px 6px; font-size: 12px; }