:root{
  /* ===== Light Theme ===== */
  --bg:#f7f7fb;
  --text:#111827;
  --muted:#6b7280;
  --line:rgba(17,24,39,.12);
  --panel:rgba(255,255,255,.92);

  --ok:#059669;
  --ng:#e11d48;

  --barOff: rgba(17,24,39,.18);
  --barOn:  rgba(17,24,39,.85);
}

*{box-sizing:border-box}
html,body{height:100%}

body{
  margin:0;
  font-family: system-ui, -apple-system, "Hiragino Sans", "Noto Sans JP", Segoe UI, Roboto, Arial, sans-serif;
  background: var(--bg);
  color:var(--text);
}

.app{
  min-height:100%;
  display:flex;
  flex-direction:column;
  align-items:center;
  padding: clamp(12px, 3vw, 18px);
  padding-top: calc(12px + env(safe-area-inset-top));
  padding-bottom: calc(12px + env(safe-area-inset-bottom));
  gap: 12px;
}

.screen{
  width:min(620px, 100%);
  flex:1;
  display:none;
  flex-direction:column;
  gap: 12px;
}
.screen.is-active{ display:flex; }

/* ===== header ===== */
.topbar{
  display:grid;
  grid-template-columns: 1fr auto;
  align-items:center;
  padding: 10px 12px;
  border: 1px solid var(--line);
  background: var(--panel);
  border-radius: 16px;
  backdrop-filter: blur(8px);
  gap: 10px;
  box-shadow: 0 6px 18px rgba(17,24,39,.06);
}
.counter{
  font-variant-numeric: tabular-nums;
  color: var(--muted);
  font-size: 14px;
  letter-spacing:.02em;
}
.qid{
  font-variant-numeric: tabular-nums;
  color: rgba(17,24,39,.60);
  font-size: 13px;
  letter-spacing:.04em;
  justify-self:end;
}

/* ===== cards ===== */
.tiles{
  width:100%;
  flex:1;
  display:flex;
  flex-direction:column;
  justify-content:center;
  gap: 12px;
  padding-bottom: 104px; /* bottom buttons */
}
.tile{
  border: 1px solid var(--line);
  background: linear-gradient(180deg, rgba(255,255,255,1), rgba(255,255,255,.92));
  border-radius: 18px;
  padding: 14px 14px;
  box-shadow: 0 12px 28px rgba(17,24,39,.08);
  text-align:center;
  display:flex;
  align-items:center;
  justify-content:center;
  min-height: 64px;
}
.tile.is-hidden{ visibility:hidden; } /* keep layout */
.tile--answer{
  border-style: dashed;
  background: rgba(255,255,255,.75);
  color: rgba(17,24,39,.92);
}

.en{
  font-size: clamp(24px, 4.6vw, 36px);
  font-weight: 860;
  letter-spacing: .03em;
  line-height: 1.12;
  word-break: break-word;
}
.ja{
  font-size: clamp(28px, 5.4vw, 44px);
  font-weight: 900;
  letter-spacing: .02em;
  line-height: 1.12;
  word-break: break-word;
}

/* ===== beat bar ===== */
.beatWrap{
  border-radius: 16px;
  border: 1px solid var(--line);
  background: rgba(255,255,255,.92);
  padding: 10px 10px;
  box-shadow: 0 8px 20px rgba(17,24,39,.06);
}
.beatBar{
  display:grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
}
.seg{
  height: 10px;
  border-radius: 999px;
  background: var(--barOff);
  box-shadow: inset 0 0 0 1px rgba(17,24,39,.10);
  transition: background .12s ease;
}
.seg.is-on{ background: var(--barOn); }

/* ===== bottom buttons ===== */
.bottomBar{
  position: fixed;
  left: 0; right: 0;
  bottom: 0;
  padding: 12px;
  padding-bottom: calc(12px + env(safe-area-inset-bottom));
  background:
    linear-gradient(180deg, rgba(247,247,251,0), rgba(247,247,251,.90) 30%, rgba(247,247,251,.98));
  backdrop-filter: blur(10px);
  border-top: 1px solid rgba(17,24,39,.10);
  display:none;
  justify-content:center;
}
.bottomBar.is-active{ display:flex; }

.buttons{
  width:min(620px, 100%);
  display:grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

button{
  appearance:none;
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 18px 12px;
  background: rgba(255,255,255,.92);
  color: var(--text);
  font-size: clamp(18px, 3.8vw, 22px);
  font-weight: 900;
  letter-spacing:.02em;
  cursor:pointer;
  user-select:none;
  touch-action: manipulation;
  box-shadow: 0 10px 22px rgba(17,24,39,.10);
  transition: transform .08s ease, box-shadow .12s ease, border-color .12s ease, background .12s ease, filter .12s ease;
}
button:active{ transform: translateY(1px); }

.btn-ok{
  border-color: rgba(5,150,105,.30);
  background: rgba(5,150,105,.10);
}
.btn-ng{
  border-color: rgba(225,29,72,.30);
  background: rgba(225,29,72,.10);
}

/* beat1-2: keep selection (changeable) */
html.select-ok #btnOk{
  box-shadow: 0 0 0 8px rgba(5,150,105,.16), 0 10px 22px rgba(17,24,39,.10);
  border-color: rgba(5,150,105,.70);
  background: rgba(5,150,105,.18);
  filter: brightness(1.02);
}
html.select-ng #btnNg{
  box-shadow: 0 0 0 8px rgba(225,29,72,.14), 0 10px 22px rgba(17,24,39,.10);
  border-color: rgba(225,29,72,.70);
  background: rgba(225,29,72,.18);
  filter: brightness(1.02);
}

/* beat3-4: highlight correct button */
html.show-correct-ok #btnOk{
  box-shadow: 0 0 0 10px rgba(5,150,105,.18), 0 10px 22px rgba(17,24,39,.10);
  border-color: rgba(5,150,105,.80);
  background: rgba(5,150,105,.22);
}
html.show-correct-ng #btnNg{
  box-shadow: 0 0 0 10px rgba(225,29,72,.16), 0 10px 22px rgba(17,24,39,.10);
  border-color: rgba(225,29,72,.80);
  background: rgba(225,29,72,.22);
}

/* ===== home ===== */
.homeTitle{
  font-size: clamp(26px, 5vw, 38px);
  font-weight: 900;
  letter-spacing:.02em;
  margin: 8px 0 0;
}
.homeList{
  display:flex;
  flex-direction:column;
  gap: 12px;
  margin-top: 8px;
}
.levelCard{
  border: 1px solid var(--line);
  background: rgba(255,255,255,.92);
  border-radius: 18px;
  padding: 12px;
  display:flex;
  flex-direction:column;
  gap: 10px;
  box-shadow: 0 10px 22px rgba(17,24,39,.08);
}
.levelHead{
  display:flex;
  justify-content:space-between;
  align-items:baseline;
  gap: 10px;
}
.levelName{
  font-size: 18px;
  font-weight: 900;
  letter-spacing:.02em;
}
.levelKey{
  color: rgba(17,24,39,.50);
  font-size: 12px;
  letter-spacing:.08em;
  font-variant-numeric: tabular-nums;
}
.levelActions{
  display:grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}
.miniBtn{
  padding: 12px 10px;
  border-radius: 14px;
  font-size: 16px;
  font-weight: 850;
  box-shadow: 0 8px 16px rgba(17,24,39,.08);
}
.startRow{
  display:grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
  align-items:center;
}
.codeInput{
  width: 100%;
  padding: 12px 12px;
  border-radius: 14px;
  border: 1px solid var(--line);
  background: rgba(255,255,255,.92);
  color: var(--text);
  font-size: 16px;
  font-weight: 850;
  letter-spacing:.12em;
  font-variant-numeric: tabular-nums;
  outline: none;
  text-align:center;
}
.codeInput::placeholder{
  color: rgba(17,24,39,.35);
  letter-spacing:.06em;
}

/* ===== result ===== */
.resultBox{
  border: 1px solid var(--line);
  background: rgba(255,255,255,.92);
  border-radius: 18px;
  padding: 18px;
  display:flex;
  flex-direction:column;
  gap: 12px;
  box-shadow: 0 12px 28px rgba(17,24,39,.10);
  margin-top: 8px;
}
.resultTitle{
  font-size: 22px;
  font-weight: 900;
  letter-spacing:.02em;
}
.resultLine{
  display:flex;
  justify-content:space-between;
  align-items:baseline;
  gap: 10px;
  font-variant-numeric: tabular-nums;
}
.resultLabel{ color: rgba(17,24,39,.70); font-weight: 800; }
.resultValue{ font-weight: 950; letter-spacing:.04em; }
.resultButtons{
  margin-top: 6px;
  display:grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.homeIntro{
  border: 1px solid var(--line);
  background: var(--panel);
  border-radius: 18px;
  padding: 14px 14px;
  box-shadow: 0 10px 22px rgba(17,24,39,.08);
  margin-top: 8px;
}

.homeIntroTitle{
  margin: 0 0 8px;
  font-size: 15px;
  font-weight: 900;
  letter-spacing: .02em;
}

.homeIntroP{
  margin: 0;
  color: var(--text);
  line-height: 1.55;
  font-size: 14px;
}

.homeIntroList{
  margin: 0;
  padding-left: 1.2em;
  color: var(--text);
  line-height: 1.55;
  font-size: 14px;
}

.homeIntroHr{
  border: none;
  border-top: 1px solid var(--line);
  margin: 12px 0;
}