/* USDT HUB — design system. See /DESIGN.md for rationale. */

:root {
  --bg: #fff;
  --text: #000;
  --muted: #6b7280;
  --line: #e5e7eb;
  --link: #2563eb;
  --link-soft: #bfdbfe;
  --soft: #f9fafb;
  --warn-bg: #fff7ed;
  --warn-line: #fed7aa;
  --max: 760px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.65 -apple-system, BlinkMacSystemFont, "SF Pro Text",
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei",
    "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  letter-spacing: -0.005em;
}

.wrap { width: min(var(--max), calc(100% - 32px)); margin: 0 auto; }

header { padding: 24px 0 18px; border-bottom: 1px solid var(--line); background: linear-gradient(180deg, #fff, #f8fbff); }

main { padding: 32px 0 64px; }

h1, h2, h3 { font-weight: 500; letter-spacing: -0.02em; }
h1 {
  font-size: clamp(28px, 5vw, 40px);
  line-height: 1.15;
  letter-spacing: -0.03em;
  margin: 0 0 12px;
}
h2 {
  font-size: clamp(22px, 3vw, 28px);
  line-height: 1.25;
  margin: 40px 0 12px;
  padding-top: 12px;
  border-top: 1px solid var(--line);
}
h3 {
  font-size: 18px;
  line-height: 1.3;
  margin: 24px 0 8px;
}

.home-section-heading {
  font-size: clamp(24px, 3.5vw, 32px);
  line-height: 1.2;
  margin-top: 30px;
}

.home-intro-heading {
  font-size: 17px;
  line-height: 1.65;
  letter-spacing: -0.005em;
  font-weight: 400;
  margin: 0 0 4px;
}

p { margin: 0 0 14px; }
ul, ol { margin: 10px 0 16px 22px; }
li { margin: 6px 0; }

a {
  color: var(--link);
  text-decoration: underline;
  text-decoration-color: var(--link-soft);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}
a:hover { text-decoration-color: var(--link); }

.meta { font-size: 14px; color: var(--muted); margin-bottom: 18px; }

.kicker {
  display: block;
  font-size: 13px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-weight: 500;
  margin-bottom: 8px;
}

.note {
  background: var(--soft);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 14px 16px;
  margin: 16px 0;
}

.risk {
  background: var(--warn-bg);
  border: 1px solid var(--warn-line);
  border-radius: 8px;
  padding: 14px 16px;
  margin: 16px 0;
}

.toc {
  background: var(--soft);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 14px 18px;
  margin: 20px 0 28px;
  font-size: 15px;
}
.toc ol, .toc ul { margin: 6px 0 0 20px; }
.toc li { margin: 3px 0; }
.toc-title {
  font-size: 13px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-weight: 500;
  margin-bottom: 4px;
}

.chapter-list a { display: block; padding: 2px 0; }

.steps { padding-left: 24px; }
.steps > li { margin: 12px 0; }
.steps > li > strong:first-child { font-weight: 600; }

.source-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 12px;
  margin: 16px 0 24px;
}
.source-card {
  display: block;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--bg);
  color: var(--text);
  text-decoration: none;
  transition: border-color 0.15s ease, background 0.15s ease;
}
.source-card:hover {
  border-color: var(--link);
  background: var(--soft);
  text-decoration: none;
}
.card-kicker {
  display: block;
  font-size: 12px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-weight: 500;
  margin-bottom: 4px;
}
.card-title {
  display: block;
  font-weight: 600;
  color: var(--link);
  font-size: 15px;
  margin-bottom: 6px;
}
.card-copy {
  display: block;
  font-size: 14px;
  color: var(--text);
  line-height: 1.5;
}

footer {
  margin-top: 40px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
  font-size: 14px;
  color: var(--muted);
}

code {
  background: #f3f4f6;
  padding: 2px 6px;
  border-radius: 6px;
  font-size: 14px;
  font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  font-size: 15px;
}
th, td {
  border: 1px solid var(--line);
  padding: 10px 12px;
  text-align: left;
  vertical-align: top;
}
th { background: var(--soft); font-weight: 600; }

img { max-width: 100%; height: auto; }

.fee-tool {
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 18px;
  background: linear-gradient(180deg, #fff, #fbfdff);
  margin: 18px 0 24px;
}

.fee-tool-controls {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 12px;
  margin-bottom: 12px;
}

.fee-tool-controls label {
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 14px;
  color: var(--muted);
}

.fee-tool-controls input,
.fee-tool-controls select {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 12px 14px;
  font: inherit;
  color: var(--text);
  background: #fff;
}

.fee-tool-quick-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 10px 0 16px;
}

.fee-tool-quick-buttons button {
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #fff;
  color: var(--text);
  padding: 8px 12px;
  font: inherit;
  cursor: pointer;
}

.fee-tool-quick-buttons button:hover {
  border-color: var(--link);
  color: var(--link);
}

.fee-tool-note {
  margin-top: 0;
}

.fee-tool-summary {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 12px;
  margin: 16px 0 18px;
}

.fee-summary-card {
  border: 1px solid var(--line);
  border-radius: 10px;
  background: #fff;
  padding: 14px;
}

.fee-summary-card strong {
  display: block;
  font-size: 18px;
  line-height: 1.3;
  margin-bottom: 8px;
}

.fee-summary-card strong span {
  display: block;
  font-size: 13px;
  color: var(--muted);
  font-weight: 500;
  margin-top: 3px;
}

.fee-summary-card p {
  margin: 0 0 8px;
  font-size: 14px;
}

.fee-summary-card p:last-child {
  margin-bottom: 0;
  color: var(--muted);
}

.fee-table-wrap {
  overflow-x: auto;
  margin-top: 10px;
}

.fee-table {
  min-width: 920px;
}

.fee-table-sub {
  font-size: 13px;
  color: var(--muted);
  margin-top: 2px;
}

.fee-tool {
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--soft);
  padding: 16px;
  margin: 18px 0 22px;
}

.fee-tool-controls {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 12px;
  margin-bottom: 12px;
}

.fee-tool-controls label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 14px;
  color: var(--muted);
}

.fee-tool input,
.fee-tool select,
.fee-tool button {
  font: inherit;
}

.fee-tool input,
.fee-tool select {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 10px 12px;
  background: #fff;
  color: var(--text);
}

.fee-tool-quick-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 14px;
}

.fee-tool-quick-buttons button {
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #fff;
  padding: 6px 10px;
  cursor: pointer;
}

.fee-tool-quick-buttons button:hover {
  border-color: var(--link);
  color: var(--link);
}

.fee-tool-summary {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 12px;
  margin: 12px 0 16px;
}

.fee-summary-card {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  padding: 12px 14px;
}

.fee-summary-card strong,
.fee-summary-card span {
  display: block;
}

.fee-summary-card strong {
  margin-bottom: 4px;
}

.fee-table-wrap {
  overflow-x: auto;
}

.site-header-shell {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.site-nav,
.site-nav-links,
.site-utility-nav,
.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

.site-nav {
  justify-content: space-between;
}

.site-nav-links,
.site-utility-nav {
  font-size: 14px;
  color: var(--muted);
}

.site-utility-nav {
  gap: 10px 14px;
}

.brand {
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  text-decoration: none;
  color: var(--text);
}

.site-nav a,
.site-utility-nav a,
.button-link,
.portal-card {
  text-decoration: none;
}

.hero {
  padding: 10px 0 12px;
}

.hero-copy {
  font-size: 19px;
  line-height: 1.7;
  max-width: 58rem;
}

.eyebrow {
  display: block;
  margin: 0 0 10px;
  font-size: 13px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 600;
}

.hero-tagline {
  font-size: 18px;
  color: var(--muted);
  margin-bottom: 10px;
}

.section-head {
  margin-bottom: 10px;
}

.logo-rail-block {
  margin: 10px 0 24px;
}

.logo-rail {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.logo-pill {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 38px;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0 14px;
  background: linear-gradient(180deg, #fff, #f9fbff);
  color: var(--text);
  font-size: 14px;
}

.button-link {
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 10px 16px;
  color: var(--text);
  background: #fff;
}

.cta-row {
  margin: 14px 0 20px;
}

.button-link:hover,
.portal-card:hover {
  border-color: var(--link);
  box-shadow: 0 10px 30px rgba(37, 99, 235, 0.08);
}

.portal-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
  margin: 16px 0 24px;
}

.portal-grid--sections {
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

.spotlight-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
  margin: 12px 0 28px;
}

.spotlight-card,
.ready-block {
  border: 1px solid var(--line);
  border-radius: 16px;
  background: linear-gradient(180deg, #fff, #f8fbff);
  padding: 18px;
}

.spotlight-card h2,
.ready-block h2,
.company-block h2 {
  margin-top: 0;
  border-top: 0;
  padding-top: 0;
}

.spotlight-list {
  margin: 12px 0 18px 18px;
}

.mini-metrics {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 10px;
  margin: 16px 0 18px;
}

.mini-metric {
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #fff;
  padding: 12px 14px;
}

.mini-metric strong,
.mini-metric span {
  display: block;
}

.mini-metric strong {
  font-size: 22px;
  line-height: 1.1;
  margin-bottom: 4px;
}

.mini-metric span {
  font-size: 13px;
  color: var(--muted);
}

.portal-card {
  display: block;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: linear-gradient(180deg, #fff, #fbfdff);
  padding: 16px;
  color: var(--text);
  transition: border-color 0.15s ease, box-shadow 0.15s ease, transform 0.15s ease;
}

.portal-card:hover {
  transform: translateY(-1px);
}

.portal-card h2 {
  margin-top: 0;
  padding-top: 0;
  border-top: 0;
}

.portal-card--section .card-title {
  color: var(--text);
}

.portal-inline-links {
  display: block;
  margin-top: 10px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.6;
}

.section-list {
  margin: 12px 0 0 18px;
}

.section-list li {
  margin: 8px 0;
}

.steps-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 14px;
  margin: 16px 0 28px;
}

.step-card {
  display: block;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: #fff;
  padding: 16px;
  color: var(--text);
  text-decoration: none;
}

.step-number {
  display: inline-block;
  font-size: 12px;
  font-weight: 700;
  color: var(--muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 8px;
}

.step-card strong,
.step-card span {
  display: block;
}

.step-card span:last-child {
  margin-top: 8px;
  color: var(--muted);
  font-size: 14px;
}

.ready-block,
.company-block {
  margin: 24px 0;
}

@media (max-width: 720px) {
  .site-nav {
    align-items: flex-start;
    flex-direction: column;
  }

  .hero-copy {
    font-size: 17px;
  }
}