:root {
  --bg: #f5f7fb;
  --surface: #ffffff;
  --surface-muted: #f8fafc;
  --text: #0f172a;
  --text-muted: #475569;
  --line: #e2e8f0;
  --accent: #2563eb;
  --accent-strong: #1d4ed8;
  --shadow-soft: 0 8px 24px rgba(15, 23, 42, 0.06);
  --radius: 12px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Inter, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: var(--accent-strong);
  text-decoration: underline;
}

.site-header,
.site-footer {
  background: rgba(255, 255, 255, 0.95);
}

.site-header {
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  z-index: 30;
  backdrop-filter: blur(8px);
}

.site-footer {
  border-top: 1px solid var(--line);
  margin-top: 48px;
}

.wrap {
  width: min(1040px, 94%);
  margin: 0 auto;
  padding: 14px 0;
}

.brand {
  margin: 0;
  font-size: 1.18rem;
  font-weight: 700;
  letter-spacing: 0.01em;
}

.site-nav {
  display: flex;
  flex-wrap: nowrap;
  gap: 10px;
  margin-top: 10px;
  font-size: 0.94rem;
  overflow-x: auto;
  padding-bottom: 2px;
  scrollbar-width: thin;
}

.site-nav a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--line);
  border-radius: 999px;
  min-height: 40px;
  padding: 7px 13px;
  background: var(--surface);
  text-decoration: none;
  white-space: nowrap;
}

.site-nav a[aria-current="page"] {
  border-color: var(--accent);
  background: #eff6ff;
  color: var(--accent-strong);
  font-weight: 600;
}

main .wrap {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-soft);
  padding: clamp(20px, 3vw, 36px);
  margin-top: 16px;
  position: relative;
}

main article {
  max-width: 74ch;
}

h1,
h2,
h3 {
  line-height: 1.3;
  letter-spacing: 0;
  margin-top: 0;
}

h1 {
  font-size: clamp(1.75rem, 3.4vw, 2.35rem);
  margin-bottom: 12px;
}

h2 {
  font-size: clamp(1.2rem, 2.2vw, 1.55rem);
  margin-top: 28px;
  margin-bottom: 10px;
}

h3 {
  font-size: 1.08rem;
}

p,
li {
  color: #1e293b;
  font-size: 1rem;
}

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

.card {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
  background: var(--surface-muted);
  box-shadow: 0 2px 8px rgba(15, 23, 42, 0.04);
}

.card h2,
.card h3 {
  margin-bottom: 8px;
}

.muted {
  color: var(--text-muted);
}

article > section {
  border-top: 1px solid var(--line);
  padding-top: 14px;
  margin-top: 18px;
}

figure {
  margin: 18px 0;
}

img {
  max-width: 100%;
  height: auto;
  border-radius: calc(var(--radius) - 2px);
  border: 1px solid var(--line);
}

figcaption {
  margin-top: 8px;
  color: var(--text-muted);
  font-size: 0.92rem;
}

hr {
  border: 0;
  border-top: 1px solid var(--line);
  margin: 24px 0;
}

code {
  background: #eef2ff;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 1px 6px;
  font-size: 0.92em;
}

@media (max-width: 767px) {
  .wrap {
    width: min(100%, 96%);
  }

  .site-header {
    position: static;
    backdrop-filter: none;
  }

  .brand {
    font-size: 1.05rem;
  }

  .site-nav {
    margin-top: 8px;
    gap: 8px;
  }

  .site-nav a {
    min-height: 38px;
    font-size: 0.9rem;
    padding: 6px 11px;
  }

  main .wrap {
    padding: 16px;
    margin-top: 10px;
    border-radius: 10px;
    box-shadow: 0 4px 14px rgba(15, 23, 42, 0.05);
  }

  h1 {
    font-size: 1.55rem;
  }

  h2 {
    font-size: 1.2rem;
    margin-top: 22px;
  }

  p,
  li {
    font-size: 0.98rem;
  }

  .grid {
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .card {
    padding: 14px;
  }

  figure {
    margin: 14px 0;
  }

  figcaption {
    font-size: 0.88rem;
  }
}

@media (min-width: 768px) and (max-width: 1099px) {
  .wrap {
    width: min(1000px, 93%);
  }

  main .wrap {
    padding: 26px;
  }
}