:root {
  color-scheme: light;
  --bg: #f6f8fc;
  --panel: #ffffff;
  --panel-soft: #f9fbff;
  --text: #111827;
  --muted: #637083;
  --line: #dce4f2;
  --blue: #2558d8;
  --blue-2: #1744ad;
  --gold: #d8a13a;
  --green: #1f8a70;
  --shadow: 0 14px 38px rgba(31, 53, 94, 0.10);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  background:
    radial-gradient(circle at top left, rgba(37, 88, 216, .08), transparent 34rem),
    linear-gradient(180deg, #ffffff 0%, var(--bg) 42%, #eef4ff 100%);
  color: var(--text);
  line-height: 1.72;
  letter-spacing: 0;
}
a { color: var(--blue); text-decoration: none; }
a:hover { color: var(--blue-2); }
.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 14px clamp(18px, 4vw, 52px);
  background: rgba(255, 255, 255, .92);
  border-bottom: 1px solid rgba(220, 228, 242, .9);
  backdrop-filter: blur(14px);
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-width: 150px;
  color: #10203f;
  font-weight: 800;
  letter-spacing: .02em;
}
.brand-mark { width: 38px; height: 38px; border-radius: 12px; box-shadow: 0 8px 22px rgba(37, 88, 216, .22); }
.site-nav {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 6px;
  flex-wrap: wrap;
}
.nav-link {
  display: inline-flex;
  align-items: center;
  min-height: 36px;
  padding: 6px 11px;
  border-radius: 999px;
  color: #38465d;
  font-size: 14px;
  white-space: nowrap;
}
.nav-link.is-active,
.nav-link:hover {
  background: #edf3ff;
  color: var(--blue);
}
main {
  width: min(1180px, calc(100vw - 36px));
  margin: 0 auto;
  padding: 30px 0 54px;
}
.hero {
  position: relative;
  overflow: hidden;
  padding: clamp(30px, 5vw, 58px);
  margin: 0 0 22px;
  background: linear-gradient(135deg, #ffffff 0%, #f7fbff 56%, #fff7eb 100%);
  border: 1px solid var(--line);
  border-radius: 22px;
  box-shadow: var(--shadow);
}
.hero:after {
  content: "";
  position: absolute;
  right: -60px;
  bottom: -70px;
  width: 260px;
  height: 260px;
  border: 34px solid rgba(37, 88, 216, .10);
  border-top-color: rgba(216, 161, 58, .34);
  border-radius: 50%;
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 12px;
  padding: 7px 13px;
  border-radius: 999px;
  background: #eef4ff;
  color: var(--blue);
  font-weight: 700;
}
h1 {
  max-width: 940px;
  margin: 0;
  font-size: clamp(34px, 5.4vw, 72px);
  line-height: 1.08;
  font-weight: 850;
  letter-spacing: 0;
}
.lead {
  max-width: 880px;
  margin: 18px 0 0;
  color: #536174;
  font-size: clamp(17px, 2vw, 22px);
}
.section { margin: 22px 0; }
.section-title {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 14px;
  font-size: clamp(22px, 3vw, 32px);
  line-height: 1.25;
}
.section-title:before {
  content: "";
  width: 8px;
  height: 28px;
  border-radius: 99px;
  background: linear-gradient(180deg, var(--gold), var(--blue));
}
.grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}
.grid.two { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.card, .panel {
  background: rgba(255, 255, 255, .94);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 22px;
  box-shadow: 0 10px 26px rgba(31, 53, 94, .07);
}
.card h2, .card h3, .panel h2, .panel h3 {
  margin: 0 0 10px;
  line-height: 1.28;
}
.card p, .panel p { margin: 8px 0; color: #526174; }
.tag {
  display: inline-flex;
  margin: 0 0 12px;
  padding: 5px 11px;
  border-radius: 999px;
  background: #eef4ff;
  color: var(--blue);
  font-weight: 750;
  font-size: 14px;
}
.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 16px;
}
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 10px 16px;
  border-radius: 12px;
  background: var(--blue);
  color: #fff;
  font-weight: 800;
  box-shadow: 0 10px 22px rgba(37, 88, 216, .18);
}
.button.secondary {
  background: #fff;
  color: var(--blue);
  border: 1px solid #cbd8f4;
  box-shadow: none;
}
.note {
  padding: 16px 18px;
  background: #fffaf1;
  border: 1px solid #f0d9a9;
  border-radius: 14px;
  color: #6f5525;
}
.check-list {
  margin: 10px 0 0;
  padding: 0;
  list-style: none;
}
.check-list li {
  position: relative;
  padding-left: 24px;
  margin: 9px 0;
}
.check-list li:before {
  content: "";
  position: absolute;
  left: 0;
  top: .72em;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--gold);
  box-shadow: 0 0 0 4px rgba(216, 161, 58, .14);
}
.stat-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
}
.stat {
  padding: 18px;
  border-radius: 16px;
  background: #fff;
  border: 1px solid var(--line);
}
.stat strong {
  display: block;
  color: var(--blue);
  font-size: 30px;
  line-height: 1;
}
.table-wrap {
  overflow-x: auto;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 16px;
  box-shadow: 0 10px 26px rgba(31, 53, 94, .06);
}
table {
  width: 100%;
  min-width: 720px;
  border-collapse: collapse;
  font-size: 15px;
}
th, td {
  padding: 13px 14px;
  border-bottom: 1px solid #e7edf8;
  vertical-align: top;
  text-align: left;
}
th {
  position: sticky;
  top: 0;
  background: #f2f6ff;
  color: #233a69;
  font-weight: 850;
}
tr:last-child td { border-bottom: 0; }
.essay {
  padding: 18px;
  border-left: 4px solid var(--gold);
  background: #fbfdff;
  border-radius: 0 14px 14px 0;
}
.formula {
  display: block;
  margin: 10px 0;
  padding: 12px 14px;
  border-radius: 12px;
  background: #eef4ff;
  color: #19366c;
  font-weight: 780;
}
.site-footer {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 16px;
  justify-content: center;
  padding: 28px 20px 34px;
  border-top: 1px solid var(--line);
  background: #fff;
  color: #536174;
}
@media (max-width: 820px) {
  .site-header { position: static; align-items: flex-start; flex-direction: column; padding: 12px 16px; }
  .site-nav { justify-content: flex-start; width: 100%; overflow-x: auto; flex-wrap: nowrap; padding-bottom: 2px; }
  main { width: min(100vw - 24px, 680px); padding-top: 16px; }
  .hero { padding: 26px 22px; border-radius: 18px; }
  .grid, .grid.two, .stat-grid { grid-template-columns: 1fr; }
  .card, .panel { padding: 18px; border-radius: 14px; }
  table { min-width: 640px; }
}