:root {
  --bg: #f7f9fc;
  --surface: #ffffff;
  --surface-soft: #eef4fb;
  --ink: #202124;
  --muted: #5f6368;
  --line: #dfe4ea;
  --blue: #1a73e8;
  --blue-dark: #1558b0;
  --blue-soft: #e8f0fe;
  --green: #2e7d5b;
  --shadow: 0 18px 50px rgba(60, 64, 67, .11);
  --soft-shadow: 0 1px 2px rgba(60, 64, 67, .16), 0 10px 28px rgba(60, 64, 67, .08);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 18% 0%, rgba(26, 115, 232, .10), transparent 290px),
    linear-gradient(180deg, #fbfdff 0%, var(--bg) 420px),
    var(--bg);
  font-family: "Google Sans Text", "Segoe UI", system-ui, sans-serif;
}

a { color: inherit; }

.shell {
  width: min(1080px, calc(100% - 36px));
  margin: 0 auto;
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 22px 0;
  color: var(--muted);
  font-size: 14px;
  position: relative;
  z-index: 1;
}

.brand {
  display: inline-flex;
  align-items: center;
  color: var(--ink);
  text-decoration: none;
  font-size: 24px;
  font-weight: 850;
  letter-spacing: -.045em;
  line-height: 1;
}

.nav-links {
  display: flex;
  gap: 6px;
  align-items: center;
  flex-wrap: wrap;
  justify-content: flex-end;
  background: rgba(255, 255, 255, .72);
  border: 1px solid rgba(223, 228, 234, .78);
  border-radius: 999px;
  padding: 4px;
  box-shadow: 0 1px 2px rgba(60, 64, 67, .08);
}

.nav-links a {
  text-decoration: none;
  padding: 8px 10px;
  border-radius: 999px;
  transition: background .18s ease, color .18s ease;
  white-space: nowrap;
}

.nav-links a:hover {
  background: var(--blue-soft);
  color: var(--blue-dark);
}

.hero {
  padding: 64px 0 52px;
  border-top: 1px solid rgba(95, 99, 104, .14);
}

.breadcrumb {
  color: var(--muted);
  font-size: 14px;
  margin-bottom: 28px;
}

.breadcrumb a { text-decoration: none; }

.kicker {
  color: var(--blue);
  font-weight: 900;
  font-size: 13px;
  letter-spacing: .11em;
  text-transform: uppercase;
}

h1, h2, h3, p { margin-top: 0; }

h1 {
  max-width: 840px;
  margin: 12px 0 20px;
  font-size: clamp(40px, 6vw, 70px);
  line-height: 1;
  font-weight: 760;
  letter-spacing: -.035em;
}

.lead {
  max-width: 760px;
  color: var(--muted);
  font-size: 19px;
  line-height: 1.62;
}

.article-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 34px;
  align-items: start;
  padding: 22px 0 76px;
}

.article {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 28px;
  padding: clamp(24px, 4vw, 44px);
  box-shadow: 0 1px 2px rgba(60, 64, 67, .08);
  position: relative;
  overflow: hidden;
}

.article::before {
  content: "";
  position: absolute;
  inset: 0 0 auto;
  height: 4px;
  background: linear-gradient(90deg, var(--blue), rgba(46, 125, 91, .78));
}

.article h2 {
  margin: 34px 0 12px;
  font-size: clamp(26px, 3vw, 36px);
  line-height: 1.08;
}

.article h3 {
  margin: 24px 0 8px;
  font-size: 20px;
}

.article p,
.article li {
  color: #3f4a45;
  line-height: 1.72;
  font-size: 16px;
}

.article ul,
.article ol {
  padding-left: 22px;
}

.summary-box,
.note-box {
  background: var(--surface-soft);
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 20px;
  margin: 26px 0;
}

.note-box {
  background: #fffaf0;
}

.sidebar {
  position: sticky;
  top: 18px;
  display: grid;
  gap: 14px;
}

.side-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 22px;
  padding: 20px;
  box-shadow: 0 1px 2px rgba(60, 64, 67, .08);
}

.side-card h2,
.side-card h3 {
  font-size: 17px;
  margin-bottom: 12px;
}

.side-card a {
  display: block;
  color: var(--blue);
  text-decoration: none;
  margin-top: 10px;
  line-height: 1.45;
  font-weight: 650;
}

.side-card a:hover {
  color: var(--blue-dark);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 12px 16px;
  border-radius: 999px;
  text-decoration: none;
  font-weight: 700;
}

.btn-primary {
  background: var(--blue);
  color: #fff;
}

.btn-primary:hover { background: var(--blue-dark); }

.grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  padding: 22px 0 84px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 24px;
  padding: 24px;
  text-decoration: none;
  box-shadow: 0 1px 2px rgba(60, 64, 67, .08);
  min-height: 188px;
  transition: transform .2s ease, box-shadow .2s ease, border-color .2s ease;
}

.card:hover {
  border-color: #c9d4e5;
  box-shadow: var(--soft-shadow);
  transform: translateY(-2px);
}

.card span {
  color: var(--blue);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: .08em;
  text-transform: uppercase;
}

.card h2 {
  font-size: 22px;
  line-height: 1.15;
  margin: 12px 0 10px;
  letter-spacing: -.015em;
}

.card p {
  color: var(--muted);
  line-height: 1.6;
  margin-bottom: 0;
}

footer {
  border-top: 1px solid rgba(95, 99, 104, .14);
  padding: 32px 0 46px;
  color: var(--muted);
  font-size: 14px;
}

@media (max-width: 900px) {
  .nav {
    align-items: flex-start;
    flex-direction: column;
    gap: 12px;
    padding: 18px 0;
  }

  .nav-links {
    justify-content: flex-start;
    flex-wrap: nowrap;
    max-width: 100%;
    overflow-x: auto;
  }

  .article-layout {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
  }

  .grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 560px) {
  .shell { width: min(100% - 26px, 1080px); }
  h1 { font-size: 39px; }
  .hero { padding-top: 40px; }
  .article { padding: 22px; }
}