:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #14141f;
  --bg-tertiary: #1e1e2e;
  --text-primary: #ffffff;
  --text-secondary: #a0a0b0;
  --text-muted: #606070;
  --accent: #00d4ff;
  --accent-secondary: #00ff88;
  --danger: #ff4466;
  --focus-ring: #00d4ff;
  --focus-glow: rgba(0, 212, 255, 0.4);
  --radius-md: 12px;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html, body {
  width: 600px; height: 600px; overflow: hidden;
  background: #000;
  color: var(--text-primary);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}
#app { width: 100%; height: 100%; position: relative; }
.screen { width: 100%; height: 100%; position: absolute; top: 0; left: 0; display: flex; flex-direction: column; }
.screen.hidden { display: none; }
.focusable { transition: all 0.15s ease; border: 2px solid transparent; cursor: pointer; outline: none; }
.focusable:focus { border-color: var(--focus-ring); box-shadow: 0 0 20px var(--focus-glow); }
.hidden { display: none !important; }

/* ---------- Header ---------- */
.hdr { padding: 28px 32px 18px; }
.hdr-row {
  display: flex; align-items: center; gap: 16px;
  padding: 22px 28px 16px;
  border-bottom: 1px solid var(--bg-tertiary);
}
.hdr-title { font-size: 40px; font-weight: 800; letter-spacing: -0.5px; }
.hdr-title.sm { font-size: 26px; font-weight: 700; }
.hdr-sub { margin-top: 8px; font-size: 18px; color: var(--text-secondary); }
.hdr-mid { flex: 1; display: flex; align-items: center; justify-content: space-between; gap: 12px; }

.icon-btn {
  flex: none;
  width: 56px; height: 56px;
  display: flex; align-items: center; justify-content: center;
  font-size: 28px; line-height: 1;
  background: var(--bg-secondary);
  color: var(--text-primary);
  border-radius: var(--radius-md);
}

/* ---------- Home menu ---------- */
.menu {
  flex: 1;
  display: flex; flex-direction: column; gap: 14px;
  padding: 18px 28px 28px;
  overflow: hidden;
}
.menu-item {
  display: flex; align-items: center; gap: 18px;
  min-height: 92px;
  padding: 16px 22px;
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
  text-align: left;
  color: var(--text-primary);
}
.menu-icon {
  flex: none;
  width: 56px; height: 56px;
  display: flex; align-items: center; justify-content: center;
  font-size: 26px;
  background: var(--bg-tertiary);
  border-radius: 10px;
  color: var(--accent);
}
.menu-text { display: flex; flex-direction: column; gap: 4px; }
.menu-label { font-size: 24px; font-weight: 700; }
.menu-hint { font-size: 16px; color: var(--text-secondary); }

/* ---------- Status badge ---------- */
.status-badge {
  flex: none;
  padding: 6px 14px;
  font-size: 15px; font-weight: 700;
  border-radius: 999px;
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  text-transform: uppercase; letter-spacing: 0.5px;
}
.status-badge.is-known { background: rgba(0,255,136,0.15); color: var(--accent-secondary); }
.status-badge.is-learning { background: rgba(255,68,102,0.15); color: var(--danger); }

/* ---------- Flashcards ---------- */
.fc-counter { font-size: 20px; font-weight: 700; color: var(--text-secondary); }
.fc-stage {
  flex: 1;
  display: flex; align-items: center; justify-content: center;
  padding: 24px 32px;
}
.card {
  position: relative;
  width: 100%; height: 100%;
  border-radius: 18px;
  background: linear-gradient(160deg, var(--bg-tertiary), var(--bg-secondary));
}
.card:focus { border-color: var(--focus-ring); box-shadow: 0 0 24px var(--focus-glow); }
.card-face {
  position: absolute; inset: 0;
  display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  gap: 14px; padding: 28px; text-align: center;
}
.card-pos {
  font-size: 18px; font-style: italic;
  color: var(--accent);
}
.card-word {
  font-size: 52px; font-weight: 800; letter-spacing: -1px;
  word-break: break-word;
}
.card-def {
  font-size: 30px; font-weight: 600; line-height: 1.4;
  color: var(--text-primary);
}
.card-tip {
  position: absolute; bottom: 22px; left: 0; right: 0;
  font-size: 15px; color: var(--text-muted);
}
.fc-controls {
  display: grid; grid-template-columns: 1fr 1fr 1fr 1fr;
  gap: 10px; padding: 18px 24px 26px;
}

/* ---------- Buttons ---------- */
.ctl-btn {
  min-height: 64px;
  display: flex; align-items: center; justify-content: center;
  padding: 10px 12px;
  font-size: 17px; font-weight: 700;
  background: var(--bg-secondary);
  color: var(--text-primary);
  border-radius: var(--radius-md);
  text-align: center;
}
.ctl-btn.ctl-wide { min-height: 72px; font-size: 20px; width: 100%; }
.ctl-known { color: var(--accent-secondary); }
.ctl-learn { color: var(--danger); }
.ctl-danger { color: var(--danger); }

/* ---------- Letter grid ---------- */
.letter-grid {
  flex: 1;
  display: grid; grid-template-columns: repeat(5, 1fr);
  gap: 12px; padding: 24px 28px;
  align-content: start;
  overflow-y: auto;
}
.letter-cell {
  min-height: 84px;
  display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  gap: 2px;
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
  color: var(--text-primary);
}
.letter-cell .lc-char { font-size: 30px; font-weight: 800; }
.letter-cell .lc-count { font-size: 13px; color: var(--text-secondary); }

/* ---------- Word list ---------- */
.word-list {
  flex: 1;
  display: flex; flex-direction: column; gap: 10px;
  padding: 20px 28px;
  overflow-y: auto;
}
.word-row {
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  min-height: 64px;
  padding: 12px 20px;
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
  color: var(--text-primary);
}
.word-row .wr-word { font-size: 24px; font-weight: 700; }
.word-row .wr-pos { font-size: 16px; font-style: italic; color: var(--accent); }
.word-row .wr-dot {
  width: 12px; height: 12px; border-radius: 50%;
  background: var(--bg-tertiary); flex: none;
}
.word-row .wr-dot.is-known { background: var(--accent-secondary); }
.word-row .wr-dot.is-learning { background: var(--danger); }

/* ---------- Detail ---------- */
.detail-body {
  flex: 1;
  display: flex; flex-direction: column; justify-content: center;
  gap: 16px; padding: 32px 40px;
}
.detail-pos { font-size: 20px; font-style: italic; color: var(--accent); }
.detail-word { font-size: 48px; font-weight: 800; letter-spacing: -1px; word-break: break-word; }
.detail-def { font-size: 28px; line-height: 1.45; color: var(--text-primary); }
.detail-controls { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; padding: 18px 28px 28px; }

/* ---------- Quiz ---------- */
.quiz-score { font-size: 20px; font-weight: 700; color: var(--text-secondary); }
.quiz-body { flex: 1; display: flex; flex-direction: column; padding: 20px 28px; overflow: hidden; }
.quiz-prompt { font-size: 18px; color: var(--text-secondary); }
.quiz-def {
  font-size: 26px; font-weight: 600; line-height: 1.35;
  margin: 10px 0 18px;
}
.quiz-options { display: flex; flex-direction: column; gap: 10px; }
.quiz-opt {
  min-height: 64px;
  display: flex; align-items: center; gap: 12px;
  padding: 12px 20px;
  font-size: 22px; font-weight: 700;
  background: var(--bg-secondary);
  color: var(--text-primary);
  border-radius: var(--radius-md);
  text-align: left;
}
.quiz-opt.is-correct { background: rgba(0,255,136,0.18); color: var(--accent-secondary); }
.quiz-opt.is-wrong { background: rgba(255,68,102,0.18); color: var(--danger); }
.quiz-feedback { margin-top: 16px; font-size: 20px; font-weight: 700; text-align: center; }
.quiz-feedback.ok { color: var(--accent-secondary); }
.quiz-feedback.no { color: var(--danger); }
.quiz-controls { padding: 14px 28px 26px; }

/* ---------- Progress ---------- */
.prog-body { flex: 1; display: flex; flex-direction: column; justify-content: center; gap: 28px; padding: 28px 36px; }
.prog-bar { width: 100%; height: 22px; background: var(--bg-tertiary); border-radius: 999px; overflow: hidden; }
.prog-fill { height: 100%; width: 0%; background: linear-gradient(90deg, var(--accent), var(--accent-secondary)); transition: width 0.3s ease; }
.prog-stats { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 14px; }
.stat {
  display: flex; flex-direction: column; align-items: center; gap: 6px;
  padding: 22px 12px;
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
}
.stat-num { font-size: 40px; font-weight: 800; }
.stat-label { font-size: 15px; color: var(--text-secondary); text-transform: uppercase; letter-spacing: 0.5px; }
.stat-known .stat-num { color: var(--accent-secondary); }
.stat-learn .stat-num { color: var(--danger); }
.stat-new .stat-num { color: var(--accent); }
.prog-quiz { font-size: 20px; color: var(--text-secondary); text-align: center; }
.prog-controls { padding: 14px 28px 28px; }