:root {
  --ink: #0f172a;
  --ink-soft: #1e293b;
  --accent: #3b6cf0;
  --accent-soft: #5b86f5;
  --paper: #f4f7fb;
  --muted: #64748b;
  --line: #dbe3f0;
  --white: #ffffff;
  --max: 42rem;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 1.05rem;
  line-height: 1.65;
  color: var(--ink);
  background:
    radial-gradient(ellipse 80% 50% at 8% -10%, rgba(59, 108, 240, 0.16), transparent 55%),
    radial-gradient(ellipse 55% 40% at 100% 0%, rgba(15, 23, 42, 0.05), transparent 50%),
    var(--paper);
}

a {
  color: var(--ink);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
}

a:hover {
  color: var(--accent);
}

.wrap {
  width: min(100% - 2.5rem, 56rem);
  margin: 0 auto;
}

.site-header {
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--line);
  background: rgba(244, 247, 251, 0.88);
  backdrop-filter: blur(10px);
  position: sticky;
  top: 0;
  z-index: 10;
}

.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  color: var(--ink);
  text-decoration: none;
}

.brand-mark {
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 0.55rem;
  object-fit: contain;
  background: var(--white);
  box-shadow: 0 0 0 1px var(--line);
  flex-shrink: 0;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.brand-name {
  font-family: "Source Serif 4", Georgia, "Times New Roman", serif;
  font-size: 1.35rem;
  font-weight: 600;
  letter-spacing: 0.01em;
}

.brand-subtitle {
  margin-top: 0.15rem;
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.hero-logo {
  display: block;
  width: 5.5rem;
  height: 5.5rem;
  margin: 0 0 1.25rem;
  border-radius: 1rem;
  object-fit: contain;
  background: var(--white);
  box-shadow: 0 0 0 1px var(--line);
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem 1.15rem;
  font-size: 0.92rem;
}

.nav a {
  text-decoration: none;
  color: var(--ink-soft);
}

.nav a:hover,
.nav a[aria-current="page"] {
  color: var(--ink);
  text-decoration: underline;
  text-decoration-color: var(--accent);
}

main {
  padding: 2.75rem 0 4rem;
}

.hero {
  padding: 3.5rem 0 2.5rem;
  max-width: 36rem;
}

.hero h1 {
  margin: 0 0 0.85rem;
  font-family: "Source Serif 4", Georgia, "Times New Roman", serif;
  font-size: clamp(2.4rem, 5vw, 3.4rem);
  font-weight: 600;
  line-height: 1.12;
  letter-spacing: -0.02em;
}

.hero p {
  margin: 0 0 1.75rem;
  color: var(--muted);
  font-size: 1.12rem;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.8rem 1.2rem;
  border-radius: 999px;
  border: 1px solid transparent;
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}

.button-primary {
  background: var(--accent);
  color: var(--white);
}

.button-primary:hover {
  background: var(--accent-soft);
  color: var(--white);
}

.button-secondary {
  background: transparent;
  border-color: var(--line);
  color: var(--ink);
}

.button-secondary:hover {
  border-color: var(--accent);
  color: var(--ink);
}

.prose {
  max-width: var(--max);
}

.prose h1 {
  margin: 0 0 0.5rem;
  font-family: "Source Serif 4", Georgia, "Times New Roman", serif;
  font-size: clamp(2rem, 4vw, 2.6rem);
  font-weight: 600;
  line-height: 1.15;
}

.meta {
  margin: 0 0 2rem;
  color: var(--muted);
  font-size: 0.92rem;
}

.prose h2 {
  margin: 2.25rem 0 0.65rem;
  font-size: 1.2rem;
  line-height: 1.3;
}

.prose h3 {
  margin: 1.5rem 0 0.5rem;
  font-size: 1.05rem;
}

.prose p,
.prose ul,
.prose table {
  margin: 0 0 1rem;
}

.prose ul {
  padding-left: 1.2rem;
}

.prose li {
  margin-bottom: 0.4rem;
}

.prose table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
}

.prose th,
.prose td {
  border: 1px solid var(--line);
  padding: 0.55rem 0.65rem;
  text-align: left;
  vertical-align: top;
}

.prose th {
  background: rgba(59, 108, 240, 0.06);
}

.note {
  margin: 1.5rem 0;
  padding: 1rem 1.1rem;
  border-left: 3px solid var(--accent);
  background: rgba(59, 108, 240, 0.08);
}

.site-footer {
  border-top: 1px solid var(--line);
  padding: 1.5rem 0 2.25rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.site-footer .wrap {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.25rem;
  justify-content: space-between;
}

.site-footer a {
  color: var(--muted);
  text-decoration: none;
}

.site-footer a:hover {
  color: var(--ink);
}

@media (max-width: 640px) {
  .site-header .wrap {
    align-items: flex-start;
    flex-direction: column;
  }

  .nav {
    gap: 0.7rem 1rem;
  }
}