:root {
  --bg: #f4f4f7;
  --card: #fff;
  --line: #e6e6ec;
  --ink: #1a1a22;
  --ink-2: #5a5a6b;
  --ink-3: #9191a3;
  --brand: #0b6bcb;
  --brand-soft: #e6f0fb;
  --radius: 16px;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--bg); color: var(--ink);
  font: 15px/1.6 -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
  -webkit-font-smoothing: antialiased; padding-bottom: 40px;
}
.wrap { max-width: 560px; margin: 0 auto; padding: 20px 16px 0; }

.top { display: flex; align-items: center; justify-content: space-between; padding: 4px 2px 16px; }
.brand { display: flex; align-items: center; gap: 9px; }
.dot { width: 11px; height: 11px; border-radius: 50%; background: var(--brand); box-shadow: 0 0 0 4px var(--brand-soft); }
.brand h1 { font-size: 17px; font-weight: 600; margin: 0; }
.weak { font-size: 12px; color: var(--ink-3); }

.kinds { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 14px; }
.kind {
  border: 1px solid var(--line); background: #fff; border-radius: 20px;
  padding: 6px 13px; font-size: 13px; color: var(--ink-2); cursor: pointer; font-family: inherit;
  transition: .15s;
}
.kind:hover { border-color: #c9d9f3; }
.kind.on { background: var(--brand); border-color: var(--brand); color: #fff; font-weight: 500; }

.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 18px; margin-bottom: 14px; }
.card h2 { font-size: 13px; font-weight: 600; color: var(--ink-2); margin: 0 0 12px; letter-spacing: .3px; }

.pair { display: flex; align-items: flex-end; gap: 10px; }
.side { flex: 1; min-width: 0; }
.side input {
  width: 100%; border: 1px solid var(--line); background: #fbfbfd; border-radius: 11px;
  padding: 11px 12px; font-size: 19px; font-weight: 600; color: var(--ink);
  font-family: inherit; font-variant-numeric: tabular-nums; outline: none;
}
.side input:focus { border-color: #b8d1f2; background: #fff; }
.side input::-webkit-outer-spin-button, .side input::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0; }
.side select {
  width: 100%; margin-top: 8px; border: 1px solid var(--line); background: #fff; border-radius: 9px;
  padding: 8px 9px; font-size: 13px; color: var(--ink-2); font-family: inherit; outline: none; cursor: pointer;
}
.swap {
  flex: 0 0 auto; width: 38px; height: 38px; border-radius: 50%; border: 1px solid var(--line);
  background: #fff; color: var(--ink-2); font-size: 15px; cursor: pointer; margin-bottom: 40px;
}
.swap:hover { background: var(--brand-soft); border-color: #b8d1f2; color: var(--brand); }

.result {
  margin-top: 14px; padding: 12px 14px; border-radius: 11px;
  background: var(--brand-soft); font-size: 14px; color: #0a5aa8; line-height: 1.6; word-break: break-all;
}
.result b { font-size: 16px; }

.quick { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.q {
  border: 1px solid var(--line); border-radius: 11px; padding: 10px 12px;
  font-size: 13px; color: var(--ink-2); background: #fbfbfd; cursor: pointer; text-align: left; font-family: inherit;
}
.q:hover { background: var(--brand-soft); border-color: #b8d1f2; }
.q em { font-style: normal; color: var(--ink); font-weight: 600; }

.foot { text-align: center; font-size: 12px; color: #b3b3c1; padding: 8px 0 20px; }

@media (max-width: 420px) {
  .pair { flex-direction: column; align-items: stretch; }
  .swap { margin: 2px auto; }
  .quick { grid-template-columns: 1fr; }
}