:root {
  --blue: #2563eb;
  --blue-d: #1d4ed8;
  --bg: #f4f5f7;
  --card: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --line: #e5e7eb;
  --again: #ef4444;
  --hard: #f59e0b;
  --good: #22c55e;
  --easy: #3b82f6;
}
* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
html, body { margin: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Kaku Gothic ProN",
    "Yu Gothic", Meiryo, sans-serif;
  background: var(--bg);
  color: var(--text);
  padding-bottom: env(safe-area-inset-bottom);
}

.topbar {
  position: sticky;
  top: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: calc(12px + env(safe-area-inset-top)) 16px 12px;
  background: var(--blue);
  color: #fff;
}
.topbar .link { font-size: 18px; font-weight: 700; }
.icon-btn { font-size: 20px; background: none; border: none; color: #fff; }

main { max-width: 640px; margin: 0 auto; padding: 16px; }
.screen { display: flex; flex-direction: column; gap: 16px; }
.hidden { display: none !important; }

button { cursor: pointer; font-family: inherit; }
.link { background: none; border: none; color: inherit; }

.primary {
  background: var(--blue);
  color: #fff;
  border: none;
  border-radius: 12px;
  padding: 14px 18px;
  font-size: 16px;
  font-weight: 700;
}
.primary:active { background: var(--blue-d); }
.big { width: 100%; padding: 16px; font-size: 17px; }

.secondary {
  background: #eef2ff;
  color: var(--blue-d);
  border: 1px solid #c7d2fe;
  border-radius: 12px;
  padding: 14px 18px;
  font-size: 16px;
  font-weight: 700;
}
.secondary:active { background: #e0e7ff; }

/* ホーム */
.stats {
  display: flex;
  gap: 10px;
  margin-top: 8px;
}
.stat {
  flex: 1;
  background: var(--card);
  border-radius: 12px;
  padding: 16px 8px;
  text-align: center;
  border: 1px solid var(--line);
}
.stat .num { display: block; font-size: 28px; font-weight: 800; }
.stat .lbl { font-size: 12px; color: var(--muted); }
#stat-due { color: var(--blue); }
#stat-new { color: var(--good); }
#stat-archived { color: var(--muted); }

/* ヒアリングモード（ターゲット語句を空欄にして聞き取りテスト） */
.listen-note {
  font-size: 13px;
  font-weight: 600;
  color: var(--blue-d);
  margin-bottom: 10px;
}
.face .blank {
  color: var(--blue-d);
  border-bottom: 2px solid var(--blue-d);
  letter-spacing: 1px;
}

.card-list { display: flex; flex-direction: column; gap: 10px; }
.action {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 2px;
  text-align: left;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 14px 16px;
  width: 100%;
  color: var(--text);
}
.action-main { font-weight: 700; font-size: 15px; }
.action-sub { font-size: 12px; color: var(--muted); }
.action.danger { border-color: #fecaca; }
.action.danger .action-main { color: var(--again); }
.action:disabled { opacity: 0.5; cursor: default; }

/* ステージ選択 */
.stage {
  display: flex;
  align-items: center;
  gap: 12px;
  text-align: left;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 14px 16px;
  width: 100%;
  color: var(--text);
}
.stage-icon { font-size: 22px; width: 26px; text-align: center; flex: none; }
.stage-body { display: flex; flex-direction: column; gap: 2px; flex: 1 1 auto; min-width: 0; }
.stage-title { font-weight: 700; font-size: 15px; }
.stage-title small { color: var(--muted); font-weight: 400; font-size: 12px; }
.stage-sub { font-size: 12px; color: var(--muted); }
.stage-state { font-size: 12px; font-weight: 700; color: var(--muted); flex: none; }
.stage.ready { border-color: var(--blue); }
.stage.ready .stage-state { color: var(--blue); }
.stage.active { border-color: var(--hard); }
.stage.active .stage-state { color: var(--hard); }
.stage.cleared { border-color: var(--good); }
.stage.cleared .stage-state { color: var(--good); }
.stage.locked { opacity: 0.55; }
.stage:disabled { cursor: default; }

.note { font-size: 13px; color: var(--muted); }
.version { text-align: center; margin-top: 20px; }
.msg { font-size: 14px; color: var(--blue-d); min-height: 1.2em; }

/* 学習 */
.progress { text-align: center; color: var(--muted); font-size: 14px; }
.flashcard {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 24px 18px;
  min-height: 180px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}
.face { font-size: 20px; line-height: 1.6; }
.face.front { font-weight: 600; }
.face b { color: var(--blue-d); }
.face.back {
  border-top: 1px dashed var(--line);
  padding-top: 14px;
  font-size: 17px;
  font-weight: 400;
}
.back .card-img {
  display: block;
  width: 200px;
  max-width: 60%;
  height: auto;
  margin: 0 auto 12px;
  border-radius: 12px;
}
.back .jp { font-size: 18px; margin-bottom: 10px; }
.back .note { color: var(--text); margin-bottom: 12px; }
.back .ex-label { color: var(--muted); font-size: 13px; }
.back .ex-en { margin: 4px 0; }
.back .ex-jp { color: var(--muted); }
.back .src { color: var(--muted); font-size: 12px; margin-top: 10px; word-break: break-all; }
.back .src a { color: var(--blue-d); }
.replay {
  align-self: flex-start;
  background: #eef2ff;
  color: var(--blue-d);
  border: none;
  border-radius: 999px;
  padding: 8px 16px;
  font-size: 14px;
  font-weight: 700;
}
.ex-replay {
  background: #eef2ff;
  color: var(--blue-d);
  border: none;
  border-radius: 999px;
  padding: 6px 14px;
  font-size: 13px;
  margin-top: 8px;
}

.controls { display: flex; flex-direction: column; gap: 10px; }
.rate-row { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; }
.rate {
  border: none;
  border-radius: 12px;
  padding: 12px 4px;
  color: #fff;
  font-weight: 700;
  font-size: 14px;
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.rate small { font-weight: 500; font-size: 11px; opacity: 0.95; }
.rate.again { background: var(--again); }
.rate.hard { background: var(--hard); }
.rate.good { background: var(--good); }
.rate.easy { background: var(--easy); }
.quit { color: var(--muted); font-size: 13px; align-self: center; padding: 6px; }

/* 聞き流し */
.listen-controls {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
}
.lc-btn {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 999px;
  width: 56px;
  height: 56px;
  font-size: 22px;
  color: var(--blue-d);
  display: flex;
  align-items: center;
  justify-content: center;
}
.lc-btn:active { background: #eef2ff; }
.lc-play {
  background: var(--blue);
  color: #fff;
  border-color: var(--blue);
  width: 68px;
  height: 68px;
  font-size: 26px;
}
.lc-play:active { background: var(--blue-d); }
.listen-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
  text-align: left;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 12px 14px;
  width: 100%;
  color: var(--text);
}
.listen-item .li-en { font-weight: 600; font-size: 15px; }
.listen-item .li-en b { color: var(--blue-d); }
.listen-item .li-jp { font-size: 13px; color: var(--muted); }
.listen-item.playing {
  border-color: var(--blue);
  background: #eff6ff;
  box-shadow: 0 0 0 1px var(--blue) inset;
}

/* 完了 */
#screen-done { align-items: center; text-align: center; margin-top: 40px; }
.done-emoji { font-size: 56px; margin: 0; }
.done-msg { font-size: 18px; }

/* 設定 */
.field { display: flex; flex-direction: column; gap: 6px; font-size: 14px; }
.field select, .field input[type="range"] { width: 100%; padding: 8px; font-size: 15px; }
h2 { font-size: 18px; margin: 4px 0; }