:root {
  --bg: #f5f7fa;
  --card: #ffffff;
  --ink: #1f2733;
  --muted: #6b7785;
  --line: #e3e8ef;
  --brand: #2f6df0;
  --brand-d: #1f4fb0;
  --ok: #1f9d6b;
  --warn: #d98a00;
  --radius: 14px;
  --shadow: 0 6px 24px rgba(31,39,51,.08);
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.6;
}
a { color: var(--brand); text-decoration: none; }
.wrap { max-width: 960px; margin: 0 auto; padding: 0 18px; }
header.site {
  background: var(--card);
  border-bottom: 1px solid var(--line);
  position: sticky; top: 0; z-index: 10;
}
header.site .wrap { display: flex; align-items: center; justify-content: space-between; height: 60px; }
.logo { font-weight: 700; font-size: 18px; letter-spacing: .5px; }
.logo small { color: var(--muted); font-weight: 400; font-size: 12px; margin-left: 8px; }
.nav a { margin-left: 16px; font-size: 14px; color: var(--muted); }
.hero { padding: 48px 0 24px; text-align: center; }
.hero h1 { font-size: 28px; margin: 0 0 10px; }
.hero p { color: var(--muted); margin: 0 auto; max-width: 620px; }
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; padding: 24px 0 48px; }
@media (max-width: 760px){ .cards { grid-template-columns: 1fr; } }
.card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 22px; box-shadow: var(--shadow); display: flex; flex-direction: column;
}
.card h3 { margin: 0 0 6px; font-size: 18px; }
.card .tag { font-size: 12px; color: #fff; background: var(--muted); border-radius: 999px; padding: 2px 10px; align-self: flex-start; margin-bottom: 10px; }
.card .tag.free { background: var(--ok); }
.card .tag.login { background: var(--brand); }
.card p { color: var(--muted); font-size: 14px; flex: 1; }
.btn {
  display: inline-block; text-align: center; background: var(--brand); color: #fff;
  border: none; border-radius: 10px; padding: 11px 18px; font-size: 15px; cursor: pointer;
  transition: background .15s; margin-top: 14px;
}
.btn:hover { background: var(--brand-d); }
.btn.ghost { background: #fff; color: var(--brand); border: 1px solid var(--brand); }
.btn:disabled { opacity: .5; cursor: not-allowed; }
footer.site { color: var(--muted); font-size: 13px; text-align: center; padding: 30px 0 50px; }

/* 问卷页通用 */
.survey { max-width: 720px; margin: 0 auto; padding: 24px 18px 60px; }
.survey h2 { font-size: 22px; }
.consent {
  background: #fff8ec; border: 1px solid #f3d79a; color: #6b4e12; border-radius: 10px;
  padding: 14px 16px; font-size: 14px; margin: 16px 0;
}
.consent label { display: flex; gap: 8px; align-items: flex-start; cursor: pointer; }
.q { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 16px 18px; margin: 12px 0; }
.q .no { color: var(--muted); font-size: 12px; }
.q .text { font-size: 15.5px; margin: 6px 0 12px; }
.opts { display: flex; flex-wrap: wrap; gap: 8px; }
.opts label {
  border: 1px solid var(--line); border-radius: 999px; padding: 7px 14px; font-size: 14px;
  cursor: pointer; user-select: none; transition: all .12s; background: #fff;
}
.opts input { display: none; }
.opts input:checked + span { font-weight: 600; }
.opts label:has(input:checked) { border-color: var(--brand); background: #eaf1ff; color: var(--brand-d); }
.progress { height: 6px; background: var(--line); border-radius: 999px; overflow: hidden; margin: 12px 0 24px; }
.progress > i { display: block; height: 100%; background: var(--brand); width: 0; transition: width .2s; }
.row { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; margin: 10px 0; }
.input { width: 100%; padding: 10px 12px; border: 1px solid var(--line); border-radius: 10px; font-size: 15px; }
.note { color: var(--muted); font-size: 13px; }
.result {
  background: #eafaf1; border: 1px solid #b7e6cd; border-radius: 12px; padding: 22px; text-align: center; margin-top: 20px;
}
.code-box {
  font-family: ui-monospace, "SFMono-Regular", Menlo, monospace; font-size: 20px; letter-spacing: 2px;
  background: #fff; border: 1px dashed var(--brand); border-radius: 10px; padding: 14px; margin: 12px 0; color: var(--brand-d);
  word-break: break-all;
}
.coach-cta { margin-top: 14px; font-size: 14px; color: var(--muted); }
.coach-cta b { color: var(--ink); }
.toast { position: fixed; left: 50%; bottom: 30px; transform: translateX(-50%); background: #1f2733; color: #fff; padding: 10px 18px; border-radius: 8px; font-size: 14px; opacity: 0; transition: opacity .2s; pointer-events: none; z-index: 50; }
.toast.show { opacity: 1; }
.hidden { display: none !important; }
.pair-box { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 16px 18px; margin: 12px 0; }
.pair-code { font-size: 26px; letter-spacing: 4px; font-family: ui-monospace, monospace; color: var(--brand-d); font-weight: 700; }