:root {
  --purple: #7050f8;
  --purple-dark: #5a3ee0;
  --purple-soft: #efeafd;
  --bg: #f4f2fc;
  --card: #ffffff;
  --text: #241f3a;
  --muted: #8b86a3;
  --line: #e5e1f6;
  --ok: #1f9d61;
  --ok-bg: #e8f7ef;
  --bad: #e5484d;
  --bad-bg: #fdecec;
  --radius: 16px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { -webkit-text-size-adjust: 100%; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", "Helvetica Neue", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

.hidden { display: none !important; }

#app { max-width: 640px; margin: 0 auto; padding: 0 14px calc(40px + env(safe-area-inset-bottom)); }

/* ---------- 认证 ---------- */
#auth-view { min-height: 100vh; display: flex; align-items: center; }
.auth-wrap { width: 100%; padding: 28px 8px; }
.logo {
  font-size: 34px; font-weight: 800; text-align: center; letter-spacing: .5px;
  background: linear-gradient(135deg, var(--purple), #9a7bff);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.logo-sub { text-align: center; color: var(--muted); margin: 6px 0 28px; font-size: 14px; }
.auth-form { display: flex; flex-direction: column; gap: 12px; }
.auth-form input {
  width: 100%; padding: 14px 16px; border: 1.5px solid var(--line); border-radius: 12px;
  font-size: 16px; background: #fff; outline: none; transition: border-color .15s;
}
.auth-form input:focus { border-color: var(--purple); }
.divider {
  display: flex; align-items: center; gap: 12px; color: var(--muted);
  font-size: 13px; margin: 22px 0;
}
.divider::before, .divider::after { content: ""; flex: 1; height: 1px; background: var(--line); }
.err {
  background: var(--bad-bg); color: var(--bad); padding: 10px 14px; border-radius: 10px;
  font-size: 14px; margin-bottom: 14px;
}

/* ---------- 按钮 ---------- */
.btn {
  border: none; border-radius: 12px; padding: 13px 18px; font-size: 16px; font-weight: 600;
  cursor: pointer; transition: transform .06s, opacity .15s, background .15s;
  -webkit-tap-highlight-color: transparent;
}
.btn:active { transform: scale(.98); }
.btn:disabled { opacity: .45; cursor: default; }
.btn.primary { background: var(--purple); color: #fff; }
.btn.primary:not(:disabled):hover { background: var(--purple-dark); }
.btn.outline { background: transparent; color: var(--purple); border: 1.5px solid var(--purple); }
.btn.small { padding: 6px 12px; font-size: 13px; border-radius: 999px; }
.btn.ghost { background: transparent; color: var(--muted); border: 1.5px solid var(--line); }

/* ---------- 顶栏 ---------- */
.topbar {
  position: sticky; top: 0; z-index: 10;
  display: flex; align-items: center; justify-content: space-between; gap: 8px;
  padding: 12px 2px; margin-bottom: 6px;
  background: rgba(244, 242, 252, .9); backdrop-filter: blur(8px); -webkit-backdrop-filter: blur(8px);
}
.brand {
  font-weight: 800; font-size: 18px;
  background: linear-gradient(135deg, var(--purple), #9a7bff);
  -webkit-background-clip: text; background-clip: text; color: transparent;
  white-space: nowrap;
}
.topbar-right { display: flex; align-items: center; gap: 6px; }
.meta { font-size: 12px; color: var(--muted); white-space: nowrap; }

/* ---------- 卡片 ---------- */
.card {
  background: var(--card); border-radius: var(--radius);
  padding: 18px; margin: 12px 0;
  box-shadow: 0 2px 14px rgba(112, 80, 248, .07);
  border: 1px solid rgba(112, 80, 248, .06);
  animation: rise .25s ease;
}
@keyframes rise { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }

.chip {
  display: inline-block; font-size: 12px; color: var(--purple);
  background: var(--purple-soft); border-radius: 999px; padding: 3px 10px;
  margin-bottom: 10px; font-weight: 600;
}
.chip.warn { background: #fdf0e3; color: #c47a1f; }
.q { font-size: 17px; font-weight: 600; margin-bottom: 14px; }
.q .tts, .explain .tts, .right .tts, .passage .tts, .ex-line .tts {
  border: none; background: var(--purple-soft); border-radius: 8px;
  padding: 3px 8px; font-size: 14px; cursor: pointer; margin-left: 6px; vertical-align: 1px;
}
.sub { color: var(--muted); font-size: 13px; }

.opt {
  display: block; width: 100%; text-align: left;
  border: 1.5px solid var(--line); background: #fff; color: var(--text);
  border-radius: 12px; padding: 13px 15px; font-size: 16px; margin: 8px 0;
  cursor: pointer; transition: border-color .12s, background .12s;
  -webkit-tap-highlight-color: transparent;
}
.opt.sel { border-color: var(--purple); background: var(--purple-soft); font-weight: 600; }

.conf-row { display: flex; gap: 8px; margin: 14px 0 4px; }
.conf {
  flex: 1; border: 1.5px solid var(--line); background: #fff; color: var(--muted);
  border-radius: 999px; padding: 8px; font-size: 14px; cursor: pointer;
}
.conf.active { border-color: var(--purple); color: var(--purple); background: var(--purple-soft); font-weight: 600; }

textarea.answer {
  width: 100%; min-height: 88px; padding: 13px 15px; font-size: 16px;
  border: 1.5px solid var(--line); border-radius: 12px; outline: none;
  font-family: inherit; resize: vertical; background: #fff;
}
textarea.answer:focus { border-color: var(--purple); }

.busy { text-align: center; color: var(--purple); font-size: 14px; padding: 10px 0; }
.spin { display: inline-block; width: 16px; height: 16px; border: 2px solid var(--purple-soft);
  border-top-color: var(--purple); border-radius: 50%; animation: rot .7s linear infinite; vertical-align: -3px; margin-right: 6px; }
@keyframes rot { to { transform: rotate(360deg); } }

/* ---------- 结果 ---------- */
.card.ok { border-left: 4px solid var(--ok); }
.card.bad { border-left: 4px solid var(--bad); }
.result { font-size: 17px; font-weight: 700; margin-bottom: 8px; }
.card.ok .result { color: var(--ok); }
.card.bad .result { color: var(--bad); }
.your { font-size: 14px; color: var(--muted); margin-bottom: 4px; }
.right { font-size: 15px; font-weight: 600; margin: 6px 0; }
.explain {
  margin-top: 10px; padding: 12px 14px; background: var(--bg); border-radius: 12px;
  font-size: 14.5px;
}
.hint { font-size: 13px; color: var(--muted); margin-top: 8px; }

/* ---------- 阅读 / 微课 ---------- */
.passage {
  font-size: 16.5px; line-height: 1.75; margin: 6px 0 12px;
  border-left: 3px solid var(--purple); padding-left: 12px;
}
.translation { font-size: 14px; color: var(--muted); margin: 8px 0 12px; }
details.context { margin: 8px 0 12px; }
details.context summary { font-size: 13px; color: var(--purple); cursor: pointer; }
details.context .passage { font-size: 14px; border-left-color: var(--line); color: var(--muted); }
.lesson-title { font-size: 16px; font-weight: 700; margin-bottom: 10px; color: var(--purple-dark); }
.explain-block { margin-bottom: 12px; }
.ex-line { margin: 8px 0; }
.mistake { color: var(--bad); margin: 6px 0; font-size: 14.5px; }
.actions { display: flex; gap: 10px; margin-top: 16px; }
.actions .btn { flex: 1; }

/* ---------- 完成 / 提示 ---------- */
.done-card { text-align: center; padding: 36px 18px; }
.done-card .big { font-size: 44px; margin-bottom: 12px; }
.done-card h2 { margin-bottom: 6px; }
.done-card p { color: var(--muted); font-size: 14px; margin-bottom: 20px; }
.done-card .btn { margin: 6px 8px; }

.toast {
  position: fixed; left: 50%; bottom: 30px; transform: translateX(-50%);
  background: #2c2747; color: #fff; padding: 11px 18px; border-radius: 999px;
  font-size: 14px; z-index: 99; box-shadow: 0 6px 24px rgba(0, 0, 0, .25);
  max-width: 90vw; text-align: center;
}

.gen-wrap { text-align: center; padding: 60px 20px; color: var(--muted); }
.gen-wrap .spin { width: 26px; height: 26px; }