* { box-sizing: border-box; margin: 0; padding: 0; }
:root {
  --ink: #16324a;
  --muted: #5b7388;
  --line: #c5d5e4;
  --card: rgba(255, 255, 255, 0.92);
  --accent: #16324a;
  --green: #146c3a;
}
body {
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: linear-gradient(165deg, #eef3f8 0%, #d9e6f2 45%, #c5d8ea 100%);
  color: var(--ink);
  min-height: 100vh;
  line-height: 1.6;
  padding-bottom: 72px;
}
body.modal-open { overflow: hidden; }
body.lang-en .lang-zh { display: none !important; }
body.lang-en .lang-en { display: block !important; }
body.lang-en .lang-en[hidden] { display: block !important; }
body:not(.lang-en) .lang-en { display: none !important; }
a { color: inherit; text-decoration: none; }
a:hover { text-decoration: underline; }
.header {
  display: flex; justify-content: space-between; align-items: center; gap: 12px;
  padding: 16px 24px; position: sticky; top: 0; z-index: 30;
  background: rgba(238, 243, 248, 0.92); backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.logo-mark { width: 72px; height: 24px; display: block; }
.header-actions { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.hamburger { display: none; border: 1px solid var(--line); background: #fff; border-radius: 8px; padding: 8px 12px; cursor: pointer; }
.lang-btn {
  width: 32px; height: 32px; border-radius: 8px; border: 1px solid var(--line);
  background: #fff; font-size: 12px; font-weight: 700; cursor: pointer;
}
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 10px 16px; border-radius: 12px; border: 0; cursor: pointer;
  font-size: 14px; text-decoration: none;
}
.btn:hover { text-decoration: none; opacity: 0.94; }
.btn.solid { background: var(--accent); color: #fff; }
.btn.ghost { border: 1px solid var(--line); background: #fff; color: var(--ink); }
.btn.text { background: transparent; color: var(--muted); margin-top: 8px; width: 100%; }
.btn-lg { padding: 12px 20px; font-size: 15px; }
.btn.solid:disabled { opacity: 0.55; cursor: not-allowed; }
.header .btn.solid { width: auto; }
main {
  width: min(960px, calc(100% - 32px));
  margin: 0 auto;
  padding: 28px 0 48px;
  display: grid;
  gap: 28px;
}
.kicker { font-size: 12px; letter-spacing: 0.06em; color: var(--muted); text-transform: uppercase; }
h1 { font-size: clamp(24px, 4.5vw, 34px); margin: 8px 0 12px; line-height: 1.25; }
h2 { font-size: 20px; margin-bottom: 12px; }
h3 { font-size: 16px; margin-bottom: 6px; }
.lead { color: var(--muted); max-width: 62ch; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 18px; }
.tool-section { display: flex; justify-content: center; }
.tool-sticky {
  width: min(480px, 100%);
  position: sticky;
  top: 72px;
  z-index: 10;
}
.pitch { text-align: center; margin-bottom: 10px; font-size: 14px; color: var(--muted); }
.hot-pairs { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; margin-bottom: 12px; }
.chip {
  border: 1px solid var(--line); background: #fff; border-radius: 999px;
  padding: 6px 12px; font-size: 12px; cursor: pointer;
}
.chip:hover { border-color: var(--ink); }
.card {
  width: 100%;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 24px;
  display: grid;
  gap: 10px;
  box-shadow: 0 16px 40px #16324a14;
  position: relative;
}
.card .btn.solid { width: 100%; margin-top: 4px; }
.badge {
  position: absolute; right: 16px; top: 16px;
  font-size: 12px; background: #d7f7e3; color: var(--green);
  padding: 2px 8px; border-radius: 999px;
}
select, input[type="number"] {
  width: 100%; padding: 12px; border-radius: 10px;
  border: 1px solid var(--line); font-size: 15px; background: #fff;
}
#flipBtn {
  width: 40px; height: 40px; margin: 4px auto; border-radius: 50%;
  border: 1px solid var(--line); background: #fff; cursor: pointer;
}
.rate { font-weight: 700; font-size: 15px; }
.receive { font-size: 18px; font-weight: 700; color: var(--green); }
.rate-note { font-size: 12px; color: var(--muted); }
#hint { color: #b42318; font-size: 13px; }
.trust-grid {
  list-style: none; display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px;
}
.trust-grid li {
  text-align: center; background: var(--card); border: 1px solid var(--line);
  border-radius: 14px; padding: 14px;
}
.trust-grid strong { display: block; font-size: 20px; }
.trust-grid span { font-size: 12px; color: var(--muted); }
.panel {
  background: var(--card); border: 1px solid var(--line);
  border-radius: 16px; padding: 20px;
}
.panel-note { font-size: 13px; color: var(--muted); margin-bottom: 10px; }
.panel-links { margin-top: 12px; font-size: 14px; }
.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 14px; }
th, td { border: 1px solid var(--line); padding: 10px 12px; text-align: left; }
thead th { background: #e8f0f7; }
.rate-table a { font-weight: 600; }
.why-grid {
  list-style: none; display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px;
}
.why-grid li {
  padding: 14px; border: 1px dashed var(--line); border-radius: 12px; background: rgba(255,255,255,0.6);
}
.why-grid p { font-size: 14px; color: var(--muted); }
.steps {
  list-style: none; display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px;
  counter-reset: step;
}
.steps li {
  padding: 14px; border-radius: 12px; border: 1px dashed var(--line); background: #fff;
  font-size: 14px;
}
.steps li::before {
  counter-increment: step; content: counter(step);
  display: inline-flex; align-items: center; justify-content: center;
  width: 22px; height: 22px; border-radius: 50%;
  background: var(--accent); color: #fff; font-size: 12px; font-weight: 700; margin-right: 6px;
}
.steps li strong { display: block; margin-bottom: 4px; }
.steps li span { color: var(--muted); font-size: 13px; }
.risk {
  font-size: 13px; color: var(--muted); padding: 12px 16px;
  border-left: 3px solid #7aa3c4; background: rgba(255,255,255,0.5); border-radius: 0 8px 8px 0;
}
.faq details { margin-bottom: 8px; border: 1px solid var(--line); border-radius: 10px; padding: 12px; background: #fff; }
.faq summary { cursor: pointer; font-weight: 600; }
.faq p { margin-top: 8px; font-size: 14px; color: var(--muted); }
.modal {
  position: fixed; inset: 0; z-index: 50; background: rgba(22, 50, 74, 0.45);
  display: flex; align-items: center; justify-content: center; padding: 20px;
}
.modal[hidden] { display: none; }
.modal-panel {
  position: relative; background: #fff; border-radius: 16px; padding: 24px;
  max-width: 420px; width: 100%; box-shadow: 0 20px 50px #16324a22;
}
.modal-close {
  position: absolute; top: 10px; right: 12px; border: none; background: none;
  font-size: 26px; cursor: pointer; line-height: 1;
}
.modal-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 16px; }
.sticky-cta {
  position: fixed; bottom: 0; left: 0; right: 0; z-index: 25;
  display: none; gap: 8px; padding: 10px 16px;
  background: rgba(238, 243, 248, 0.96); border-top: 1px solid var(--line);
  backdrop-filter: blur(8px);
}
.sticky-cta .btn { flex: 1; }
.float-help {
  position: fixed; right: 16px; bottom: 88px; z-index: 20;
  padding: 10px 14px; font-size: 13px; background: #fff;
  border: 1px solid var(--line); border-radius: 999px;
  box-shadow: 0 4px 12px #16324a12; text-decoration: none;
}
.footer {
  text-align: center; padding: 24px; color: var(--muted);
  display: grid; gap: 8px;
}
.footer nav { display: flex; justify-content: center; gap: 16px; flex-wrap: wrap; }
.footer-note { font-size: 13px; max-width: 56ch; margin: 0 auto; }
@media (max-width: 720px) {
  .hamburger { display: block; }
  .header-actions { display: none; }
  .header-actions.open {
    display: flex; position: absolute; right: 16px; top: 56px;
    background: #fff; border: 1px solid var(--line); padding: 12px;
    flex-direction: column; align-items: stretch; box-shadow: 0 8px 24px #16324a18;
  }
  .trust-grid { grid-template-columns: repeat(2, 1fr); }
  .why-grid, .steps { grid-template-columns: 1fr; }
  .sticky-cta { display: flex; }
  body { padding-bottom: 64px; }
  .float-help { bottom: 72px; }
  .tool-sticky { position: static; }
}