:root {
  --bg: #f7f8fc;
  --surface: #ffffff;
  --surface-secondary: #f9fbff;
  --text-primary: #111827;
  --text-secondary: #374151;
  --text-muted: #6b7280;
  --border: #e5e7eb;
  --accent: #4f8ef7;
  --accent-dark: #2563eb;
  --accent-light: #eff6ff;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 12px 40px rgba(17, 24, 39, 0.08), 0 4px 12px rgba(17, 24, 39, 0.04);
  --radius: 18px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--text-primary);
  background:
    radial-gradient(circle at top, rgba(79, 142, 247, 0.08), transparent 32%),
    var(--bg);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent-dark);
  text-decoration: none;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(12px);
  background: rgba(255, 255, 255, 0.92);
  border-bottom: 1px solid rgba(229, 231, 235, 0.9);
}

.inner,
.wrap {
  width: min(920px, calc(100% - 32px));
  margin: 0 auto;
}

.inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  min-height: 72px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--text-primary);
  font-weight: 800;
  letter-spacing: -0.02em;
}

.brand-logo {
  width: 40px;
  height: 40px;
  border-radius: 12px;
  display: block;
}

.brand-text {
  font-size: 1.05rem;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.nav-links a {
  padding: 8px 14px;
  border-radius: 999px;
  color: var(--text-secondary);
  font-size: 0.92rem;
  font-weight: 600;
  transition: background 0.2s ease, color 0.2s ease;
}

.nav-links a:hover,
.nav-links a[aria-current="page"] {
  background: var(--accent-light);
  color: var(--accent-dark);
}

.wrap {
  margin-top: 40px;
  margin-bottom: 48px;
  padding: 40px clamp(20px, 3vw, 40px);
  background: rgba(255, 255, 255, 0.94);
  border: 1px solid rgba(229, 231, 235, 0.9);
  border-radius: 28px;
  box-shadow: var(--shadow-md);
}

h1 {
  margin: 0 0 12px;
  font-size: clamp(2rem, 4vw, 2.8rem);
  line-height: 1.15;
  letter-spacing: -0.04em;
}

.sub {
  margin: 0 0 28px;
  color: var(--text-muted);
  font-size: 0.95rem;
}

h2 {
  margin: 34px 0 12px;
  font-size: 1.2rem;
  line-height: 1.3;
  letter-spacing: -0.02em;
}

p,
ul {
  margin: 0 0 16px;
  color: var(--text-secondary);
  font-size: 0.96rem;
}

ul {
  padding-left: 20px;
}

li + li {
  margin-top: 8px;
}

strong {
  color: var(--text-primary);
}

.site-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  margin-top: 40px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
}

.site-footer a {
  font-size: 0.92rem;
  font-weight: 600;
}

.site-footer p {
  margin: 0 0 0 auto;
  color: var(--text-muted);
  font-size: 0.86rem;
}

@media (max-width: 720px) {
  .inner {
    padding: 14px 0;
    align-items: flex-start;
    flex-direction: column;
  }

  .wrap {
    margin-top: 24px;
    padding: 28px 20px;
    border-radius: 22px;
  }

  .nav-links {
    width: 100%;
  }

  .site-footer {
    align-items: flex-start;
    flex-direction: column;
  }

  .site-footer p {
    margin-left: 0;
  }
}