:root {
  --bg: #f7f7f5;
  --surface: #ffffff;
  --line: #e6e6e2;
  --line-strong: #d5d5d0;
  --ink: #1f1f1d;
  --ink-2: #5c5c57;
  --ink-3: #8b8b85;
  --blue: #185fa5;
  --blue-bg: #e6f1fb;
  --teal: #0f6e56;
  --teal-bg: #e1f5ee;
  --amber: #ba7517;
  --amber-bg: #faeeda;
  --red: #a32d2d;
  --red-bg: #fcebeb;
  --radius: 12px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Segoe UI", "Microsoft YaHei", sans-serif;
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3 { font-weight: 600; margin: 0; }
h1 { font-size: 16px; }
h2 { font-size: 20px; letter-spacing: -0.01em; }
h3 { font-size: 15px; }
p { margin: 0; }

/* ── 顶栏 ───────────────────────────────────────────── */
.topbar {
  background: var(--surface);
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  z-index: 20;
}
.topbar-inner {
  max-width: 900px;
  margin: 0 auto;
  padding: 12px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand-mark {
  width: 36px; height: 36px;
  border-radius: 9px;
  background: var(--blue);
  color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-size: 13px; font-weight: 600; letter-spacing: 0.04em;
  flex-shrink: 0;
}
.brand-sub { font-size: 12px; color: var(--ink-3); }
.topbar-right { display: flex; align-items: center; gap: 10px; }

.badge {
  font-size: 12px;
  padding: 4px 10px;
  border-radius: 999px;
  white-space: nowrap;
}
.badge-muted { background: #f1f1ee; color: var(--ink-2); }
.badge-live { background: var(--teal-bg); color: var(--teal); }
.badge-demo { background: var(--amber-bg); color: var(--amber); }

/* ── 通用按钮 ───────────────────────────────────────── */
.primary-btn {
  background: var(--blue);
  color: #fff;
  border: none;
  border-radius: 10px;
  padding: 11px 22px;
  font-size: 15px;
  font-weight: 500;
  font-family: inherit;
  cursor: pointer;
}
.primary-btn:hover { background: #0c447c; }
.primary-btn:disabled { opacity: 0.45; cursor: not-allowed; }
.primary-btn.small { padding: 9px 16px; font-size: 14px; }

.ghost-btn {
  background: transparent;
  border: 1px solid var(--line-strong);
  border-radius: 9px;
  padding: 7px 13px;
  font-size: 13px;
  color: var(--ink-2);
  font-family: inherit;
  cursor: pointer;
}
.ghost-btn:hover { border-color: var(--ink-3); color: var(--ink); }

.back-btn {
  background: none;
  border: none;
  padding: 0;
  font-size: 13px;
  color: var(--ink-3);
  font-family: inherit;
  cursor: pointer;
  margin-bottom: 10px;
}
.back-btn:hover { color: var(--blue); }

/* ── 布局 ───────────────────────────────────────────── */
.shell {
  max-width: 900px;
  margin: 0 auto;
  padding: 28px 20px 40px;
}
.view-head { margin-bottom: 22px; }
.view-sub { font-size: 13px; color: var(--ink-2); margin-top: 6px; }
.view-foot { display: flex; gap: 12px; align-items: center; margin-top: 26px; }

.notice {
  max-width: 900px;
  margin: 16px auto 0;
  padding: 11px 16px;
  background: var(--amber-bg);
  color: #633806;
  border-radius: 10px;
  font-size: 13px;
  border: 1px solid #f0d9a8;
}
.notice.error { background: var(--red-bg); color: var(--red); border-color: #f2c4c4; }

/* ── 场景卡片 ───────────────────────────────────────── */
.scene-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(255px, 1fr));
  gap: 12px;
}
.scene-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px 18px;
  text-align: left;
  font-family: inherit;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  gap: 8px;
  position: relative;
}
.scene-card:hover { border-color: var(--blue); }
.scene-card-top { display: flex; align-items: baseline; justify-content: space-between; gap: 10px; }
.scene-card h3 { font-size: 15px; }
.scene-goal { font-size: 12.5px; color: var(--ink-2); line-height: 1.55; }
.scene-meta { font-size: 11.5px; color: var(--ink-3); margin-top: 2px; }
.scene-meta.done { color: var(--teal); }

/* ── 词汇预热 ───────────────────────────────────────── */
.warmup-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 10px;
}
.word-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 14px 16px;
  cursor: pointer;
  text-align: left;
  font-family: inherit;
  display: flex;
  gap: 12px;
  align-items: flex-start;
}
.word-card:hover { border-color: var(--blue); background: #fbfcfe; }
.word-card.playing { border-color: var(--blue); background: var(--blue-bg); }
.word-icon {
  width: 26px; height: 26px; flex-shrink: 0;
  border-radius: 7px;
  background: var(--blue-bg);
  color: var(--blue);
  display: flex; align-items: center; justify-content: center;
  font-size: 11px; font-weight: 600;
}
.word-en { font-size: 15px; font-weight: 500; color: var(--ink); }
.word-cn { font-size: 12.5px; color: var(--ink-2); margin-top: 1px; }
.word-eg { font-size: 12.5px; color: var(--ink-3); margin-top: 6px; font-style: italic; }

/* ── 对话 ───────────────────────────────────────────── */
.chat-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 18px;
  flex-wrap: wrap;
}
.chat-head-left { display: flex; flex-direction: column; gap: 0; }
.chat-goal { font-size: 12.5px; color: var(--ink-2); margin-top: 3px; max-width: 520px; }
.lang-pick { font-size: 12px; color: var(--ink-3); display: flex; align-items: center; gap: 6px; }
.lang-pick select {
  font-family: inherit; font-size: 12.5px;
  padding: 5px 8px; border-radius: 8px;
  border: 1px solid var(--line-strong);
  background: var(--surface); color: var(--ink);
}

.messages { display: flex; flex-direction: column; gap: 14px; min-height: 120px; }

.msg { display: flex; gap: 10px; align-items: flex-start; }
.msg.user { flex-direction: row-reverse; }
/* 输入框是悬浮吸底的，最后一条消息要留出空间，否则会被盖住 */
.msg:last-child { scroll-margin-bottom: 150px; }
.avatar {
  width: 28px; height: 28px; flex-shrink: 0; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 11px; font-weight: 600;
}
.msg.ai .avatar { background: var(--teal-bg); color: var(--teal); }
.msg.user .avatar { background: var(--blue-bg); color: var(--blue); }

.bubble { max-width: 74%; }
.bubble-body {
  padding: 11px 15px;
  border-radius: 12px;
  font-size: 15px;
  line-height: 1.55;
}
.msg.ai .bubble-body { background: var(--surface); border: 1px solid var(--line); }
.msg.user .bubble-body { background: var(--blue); color: #fff; }
.bubble-zh { font-size: 12.5px; color: var(--ink-3); margin-top: 5px; padding-left: 3px; }
.msg.user .bubble-zh { text-align: right; padding-right: 3px; padding-left: 0; }

.correction {
  margin-top: 8px;
  background: var(--amber-bg);
  border-radius: 10px;
  padding: 10px 13px;
  font-size: 13px;
}
.correction-title { font-size: 11.5px; color: var(--amber); font-weight: 600; margin-bottom: 4px; }
.correction-del { color: var(--red); text-decoration: line-through; }
.correction-add { color: var(--teal); font-weight: 500; }
.correction-why { color: #633806; font-size: 12.5px; margin-top: 4px; }

.tip {
  margin-top: 8px;
  font-size: 12.5px;
  color: var(--ink-2);
  border-left: 2px solid var(--line-strong);
  padding-left: 10px;
}

.sys-msg {
  text-align: center;
  font-size: 12px;
  color: var(--ink-3);
  padding: 4px 0;
}

.progress-card {
  margin-top: 22px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 14px 18px;
}
.progress-title { font-size: 12px; color: var(--ink-3); margin-bottom: 8px; }
.progress-stats { display: flex; gap: 26px; flex-wrap: wrap; }
.stat-num { font-size: 20px; font-weight: 600; }
.stat-label { font-size: 11.5px; color: var(--ink-3); }
.error-item { font-size: 12.5px; color: var(--ink-2); margin-top: 6px; }

/* ── 输入区 ─────────────────────────────────────────── */
.composer {
  margin-top: 22px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 12px 14px;
  position: sticky;
  bottom: 12px;
}
.composer-row { display: flex; gap: 10px; align-items: center; }

.mic-btn {
  border: 1px solid var(--line-strong);
  background: var(--surface);
  border-radius: 10px;
  padding: 10px 18px;
  font-size: 14px;
  font-family: inherit;
  color: var(--ink);
  cursor: pointer;
  white-space: nowrap;
  display: flex;
  align-items: center;
  gap: 8px;
  user-select: none;
  -webkit-user-select: none;
  touch-action: none;
}
.mic-btn:hover { border-color: var(--blue); }
.mic-btn:disabled { opacity: 0.4; cursor: not-allowed; }
.mic-btn::before {
  content: '';
  width: 9px; height: 9px; border-radius: 50%;
  background: var(--line-strong);
}
.mic-btn.listening { border-color: var(--red); background: var(--red-bg); color: var(--red); }
.mic-btn.listening::before { background: var(--red); }

#textInput {
  flex: 1;
  min-width: 0;
  font-family: inherit;
  font-size: 15px;
  padding: 10px 13px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: #fbfbfa;
  color: var(--ink);
}
#textInput:focus { outline: none; border-color: var(--blue); background: #fff; }

.composer-foot {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  margin-top: 9px;
  font-size: 11.5px;
  color: var(--ink-3);
}
.hud { font-variant-numeric: tabular-nums; }
.hud-toggle { display: flex; align-items: center; gap: 5px; cursor: pointer; }

.footer {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 20px 40px;
}
.footer p { font-size: 11.5px; color: var(--ink-3); }

@media (max-width: 560px) {
  .shell { padding: 20px 14px 28px; }
  h2 { font-size: 18px; }
  .bubble { max-width: 88%; }
  .composer-row { flex-wrap: wrap; }
  #textInput { order: 3; width: 100%; flex-basis: 100%; }
  .chat-head-right { width: 100%; }
}