* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background: #0d1a26;
  color: #f2f2f2;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.65;
}

a {
  color: inherit;
}

header {
  background: linear-gradient(180deg, rgba(4, 8, 12, 0.94) 0%, rgba(13, 26, 38, 0.98) 100%);
  overflow: hidden;
  padding: 34px 20px 74px;
  position: relative;
}

header::before {
  background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='140' height='120' viewBox='0 0 140 120'%3E%3Cg fill='none' stroke='rgba(255,255,255,0.12)' stroke-width='1.8'%3E%3Cpath d='M35 4 L70 24 L70 64 L35 84 L0 64 L0 24 Z'/%3E%3Cpath d='M105 4 L140 24 L140 64 L105 84 L70 64 L70 24 Z'/%3E%3Cpath d='M35 64 L70 84 L70 124 L35 144 L0 124 L0 84 Z'/%3E%3Cpath d='M105 64 L140 84 L140 124 L105 144 L70 124 L70 84 Z'/%3E%3C/g%3E%3C/svg%3E");
  content: "";
  inset: 0;
  opacity: 0.72;
  pointer-events: none;
  position: absolute;
}

.nav,
.hero,
main,
footer {
  margin: 0 auto;
  max-width: 1160px;
  position: relative;
  z-index: 2;
}

.nav {
  align-items: center;
  display: flex;
  gap: 16px;
  justify-content: space-between;
  margin-bottom: 56px;
}

.nav a {
  color: #d6e1ea;
  font-weight: 700;
  text-decoration: none;
}

.nav-brand {
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.nav-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: flex-end;
}

.nav-links a {
  border: 1px solid rgba(255, 255, 255, 0.16);
  border-radius: 999px;
  padding: 8px 12px;
}

.nav-links .primary {
  background: #d6e1ea;
  border-color: #d6e1ea;
  color: #0d1a26;
}

.eyebrow {
  color: #9fb3c4;
  font-size: 0.8rem;
  font-weight: 800;
  letter-spacing: 0.18em;
  margin-bottom: 12px;
  text-transform: uppercase;
}

h1 {
  font-size: clamp(2rem, 4vw, 3.35rem);
  line-height: 1.1;
  margin-bottom: 18px;
  max-width: 880px;
}

.lead {
  color: #d6e1ea;
  font-size: 1.1rem;
  max-width: 880px;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.button {
  align-items: center;
  background: #b0b0b0;
  border: 1px solid #b0b0b0;
  border-radius: 999px;
  color: #0d1a26;
  display: inline-flex;
  font-weight: 800;
  justify-content: center;
  min-height: 46px;
  padding: 12px 22px;
  text-decoration: none;
}

.button.secondary {
  background: transparent;
  border-color: rgba(255, 255, 255, 0.24);
  color: #ffffff;
}

main {
  padding: 50px 20px 20px;
}

.section-title {
  color: #ffffff;
  font-size: 1.85rem;
  margin: 46px 0 14px;
}

.section-lead {
  color: #cbd5df;
  margin-bottom: 24px;
  max-width: 860px;
}

.article-grid,
.feature-grid,
.support-grid {
  display: grid;
  gap: 22px;
  grid-template-columns: repeat(auto-fit, minmax(270px, 1fr));
}

.article-card,
.panel,
.callout,
.toc {
  background: #142433;
  border: 1px solid #1a2d40;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.32);
}

.article-card {
  display: block;
  min-height: 100%;
  padding: 24px;
  text-decoration: none;
}

.article-card h2,
.article-card h3,
.panel h2,
.panel h3,
.callout h2 {
  color: #ffffff;
  line-height: 1.25;
  margin-bottom: 10px;
}

.article-card p,
.article-card li,
.panel p,
.panel li,
.callout p,
.toc a,
.toc li {
  color: #d0d0d0;
}

.article-card ul,
.panel ul,
.callout ul {
  margin-top: 12px;
  padding-left: 20px;
}

.article-card .meta {
  color: #9fb3c4;
  display: block;
  font-size: 0.82rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  margin-bottom: 10px;
  text-transform: uppercase;
}

.article-card:hover {
  border-color: rgba(255, 255, 255, 0.28);
  transform: translateY(-3px);
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.panel,
.callout,
.toc {
  padding: 26px;
}

.callout {
  align-items: center;
  display: grid;
  gap: 18px;
  grid-template-columns: minmax(0, 1fr) auto;
  margin-top: 42px;
}

.article-layout {
  align-items: start;
  display: grid;
  gap: 28px;
  grid-template-columns: minmax(0, 260px) minmax(0, 1fr);
}

.toc {
  position: sticky;
  top: 18px;
}

.toc h2 {
  color: #ffffff;
  font-size: 1rem;
  margin-bottom: 12px;
}

.toc ol,
.toc ul {
  display: grid;
  gap: 8px;
  list-style: none;
}

.toc a {
  text-decoration: none;
}

.toc a:hover {
  color: #ffffff;
}

.article-body {
  display: grid;
  gap: 22px;
}

.article-body section {
  scroll-margin-top: 20px;
}

.article-body h2 {
  color: #ffffff;
  font-size: 1.45rem;
  line-height: 1.25;
  margin-bottom: 10px;
}

.article-body h3 {
  color: #ffffff;
  font-size: 1.05rem;
  margin: 18px 0 6px;
}

.article-body p,
.article-body li {
  color: #d0d0d0;
}

.article-body ul,
.article-body ol {
  display: grid;
  gap: 8px;
  padding-left: 22px;
}

.article-body .panel {
  padding: 28px;
}

.checklist {
  display: grid;
  gap: 10px;
  list-style: none;
  padding-left: 0 !important;
}

.checklist li {
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid #1f3548;
  border-radius: 10px;
  padding: 12px 14px;
}

.note {
  background: rgba(214, 225, 234, 0.08);
  border-left: 3px solid #d6e1ea;
  border-radius: 10px;
  color: #d6e1ea;
  padding: 14px 16px;
}

footer {
  color: #aaaaaa;
  padding: 36px 20px 28px;
  text-align: center;
}

@media (max-width: 820px) {
  .nav,
  .callout,
  .article-layout {
    grid-template-columns: 1fr;
  }

  .nav {
    align-items: stretch;
    flex-direction: column;
    text-align: center;
  }

  .nav-links,
  .actions {
    justify-content: center;
  }

  .toc {
    position: static;
  }
}