:root {
  --bg: #f4f7fb;
  --card: #ffffff;
  --ink: #2c2c2a;
  --muted: #888780;
  --primary: #378add;
  --primary-d: #185fa5;
  --correct: #1d9e75;
  --correct-bg: #e1f5ee;
  --wrong: #e24b4a;
  --wrong-bg: #fcebeb;
  --current: #ffe9a8;
  --current-border: #ef9f27;
  --radius: 16px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--ink);
  -webkit-text-size-adjust: 100%;
}

[hidden] { display: none !important; }

.app {
  max-width: 920px;
  margin: 0 auto;
  padding: 20px 16px 40px;
}

.app-header { text-align: center; margin-bottom: 16px; }
.app-header h1 { font-size: 28px; margin: 0; font-weight: 600; }
.subtitle { color: var(--muted); margin: 6px 0 0; font-size: 15px; }

.lesson-bar { display: flex; align-items: center; flex-wrap: wrap; gap: 10px; margin-bottom: 18px; }
.lesson-label { color: var(--muted); font-size: 14px; }
.lesson-list { display: flex; flex-wrap: wrap; gap: 8px; }
.lesson-chip {
  padding: 8px 14px;
  border: 2px solid var(--primary);
  color: var(--primary-d);
  background: #fff;
  border-radius: 999px;
  font-size: 14px;
  cursor: pointer;
  transition: .15s;
}
.lesson-chip:hover { background: #e6f1fb; }
.lesson-chip.active { background: var(--primary); color: #fff; }

.play-area {
  background: var(--card);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: 0 2px 12px rgba(0, 0, 0, .05);
}

.stats { display: flex; gap: 10px; margin-bottom: 16px; flex-wrap: wrap; }
.stat {
  flex: 1;
  min-width: 70px;
  background: var(--bg);
  border-radius: 12px;
  padding: 10px;
  text-align: center;
}
.stat-val { display: block; font-size: 22px; font-weight: 600; }
.stat-key { font-size: 12px; color: var(--muted); }

.text-display {
  font-size: 26px;
  line-height: 1.9;
  letter-spacing: 1px;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  outline: none;
  user-select: none;
  white-space: pre-wrap;
  word-break: break-word;
  min-height: 120px;
}
.char { display: inline-block; padding: 2px 1px; border-radius: 6px; transition: .1s; }
.char.current { background: var(--current); box-shadow: 0 0 0 2px var(--current-border); }
.char.correct { color: var(--correct); }
.char.wrong { color: var(--wrong); background: var(--wrong-bg); }

.btn-restart {
  margin-top: 16px;
  padding: 8px 16px;
  border: 1px solid var(--muted);
  background: #fff;
  border-radius: 10px;
  cursor: pointer;
  font-size: 14px;
}

.keyboard { margin-top: 22px; user-select: none; touch-action: manipulation; overflow-x: auto; padding-bottom: 6px; }
.kb-row { display: flex; justify-content: center; gap: 6px; margin-bottom: 6px; flex-wrap: nowrap; }
.kb-spacer { width: 16px; flex: 0 0 auto; }
.key-fn { font-size: 12px; min-width: 30px; padding: 0 4px; }
.key {
  min-width: 34px;
  height: 46px;
  padding: 0 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #fff;
  border: 1px solid #d3d1c7;
  border-bottom-width: 3px;
  border-radius: 10px;
  font-size: 15px;
  font-family: inherit;
  color: var(--ink);
  cursor: pointer;
  transition: .08s;
  user-select: none;
}
.key:active { transform: translateY(1px); }
.key.active {
  background: var(--current);
  box-shadow: 0 0 0 2px var(--current-border);
}
.key-wide { min-width: 60px; }
.key-space { min-width: 220px; }

.hint { text-align: center; color: var(--muted); font-size: 13px; margin-top: 18px; }

/* 关卡"最佳成绩"徽标 */
.chip-best {
  display: inline-block;
  margin-left: 4px;
  font-size: 11px;
  color: #fff;
  background: var(--correct);
  border-radius: 999px;
  padding: 1px 7px;
  vertical-align: middle;
}

/* 功能键认知模式：把每一步渲染成"键帽卡片" */
.text-display.keys-mode {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
  justify-content: center;
  min-height: 140px;
}
.key-card {
  display: inline-flex;
  align-items: center;
  gap: 2px;
  padding: 14px 18px;
  background: var(--bg);
  border: 2px solid #d3d1c7;
  border-radius: 14px;
  transition: .12s;
}
.key-card .kc-cap {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 34px;
  height: 38px;
  padding: 0 8px;
  background: #fff;
  border: 1px solid #d3d1c7;
  border-bottom-width: 3px;
  border-radius: 9px;
  font-size: 16px;
  font-family: inherit;
}
.key-card .kc-plus { color: var(--muted); font-size: 16px; margin: 0 1px; }
.key-card.current { border-color: var(--current-border); box-shadow: 0 0 0 3px var(--current); background: #fff; }
.key-card.done { opacity: .5; }
.key-card.done .kc-cap { color: var(--correct); border-color: var(--correct); }
.key-card .kc-cap.active {
  background: var(--current);
  box-shadow: 0 0 0 2px var(--current-border);
  border-color: var(--current-border);
}

.result-modal {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, .4);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  z-index: 10;
}
.result-card {
  background: #fff;
  border-radius: var(--radius);
  padding: 28px;
  max-width: 360px;
  width: 100%;
  text-align: center;
  box-shadow: 0 8px 30px rgba(0, 0, 0, .2);
}
.result-card h2 { margin: 0 0 16px; }
.result-stats { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-bottom: 20px; }
.result-stats div { background: var(--bg); border-radius: 12px; padding: 12px; }
.result-stats b { display: block; font-size: 24px; }
.result-stats span { font-size: 12px; color: var(--muted); }
.btn-primary {
  background: var(--primary);
  color: #fff;
  border: none;
  padding: 12px 24px;
  border-radius: 12px;
  font-size: 16px;
  cursor: pointer;
}

@media (max-width: 560px) {
  .app-header h1 { font-size: 24px; }
  .text-display { font-size: 22px; }
  .key { min-width: 26px; height: 42px; font-size: 13px; padding: 0 5px; }
  .key-wide { min-width: 44px; }
  .key-space { min-width: 140px; }
}