:root {
  --bg: #07131a;
  --panel: #0f2430;
  --text: #e8f2f7;
  --muted: #9bb3c1;
  --accent: #3ecf8e;
  --accent-2: #f0b429;
  --border: #1e3a4a;
  --max: 720px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: radial-gradient(1200px 600px at 10% -10%, #123447 0%, var(--bg) 55%);
  color: var(--text);
  line-height: 1.65;
  font-size: 17px;
}

.skip {
  position: absolute;
  left: -9999px;
}
.skip:focus {
  left: 1rem;
  top: 1rem;
  background: var(--accent);
  color: #042015;
  padding: .5rem .75rem;
  z-index: 10;
  border-radius: 6px;
}

.wrap {
  width: min(100% - 2rem, var(--max));
  margin-inline: auto;
}

.site-header {
  border-bottom: 1px solid var(--border);
  background: rgba(7, 19, 26, 0.85);
  backdrop-filter: blur(8px);
  position: sticky;
  top: 0;
  z-index: 5;
}
.site-header .wrap {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  padding: .85rem 0;
}
.brand {
  margin: 0;
  font-weight: 700;
  letter-spacing: .02em;
  color: var(--accent);
}
.tag {
  margin: 0;
  color: var(--muted);
  font-size: .9rem;
}

h1 {
  font-size: clamp(1.55rem, 4.5vw, 2.15rem);
  line-height: 1.25;
  margin: 1.4rem 0 .75rem;
}
h2 {
  font-size: 1.35rem;
  margin: 2rem 0 .75rem;
  color: #fff;
}
h3 {
  font-size: 1.05rem;
  margin: 1rem 0 .4rem;
  color: var(--accent-2);
}

.lead {
  color: #d5e6ef;
  font-size: 1.05rem;
}

.toc {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1rem 1.1rem;
  margin: 1.5rem 0;
}
.toc-title {
  margin: 0 0 .5rem;
  font-size: 1rem;
  color: var(--accent);
}
.toc ol {
  margin: 0;
  padding-left: 1.2rem;
}
.toc a { color: #b9e7ff; }

section {
  margin-bottom: 1.25rem;
}

ul, ol { padding-left: 1.25rem; }
li { margin: .35rem 0; }

.steps {
  counter-reset: step;
  list-style: none;
  padding-left: 0;
}
.steps li {
  position: relative;
  padding: .85rem 1rem .85rem 3.1rem;
  margin: .65rem 0;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
}
.steps li::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  left: .85rem;
  top: .85rem;
  width: 1.7rem;
  height: 1.7rem;
  border-radius: 50%;
  background: var(--accent);
  color: #042015;
  font-weight: 700;
  display: grid;
  place-items: center;
  font-size: .95rem;
}

.note {
  background: #132a18;
  border-left: 4px solid var(--accent);
  padding: .75rem 1rem;
  border-radius: 0 8px 8px 0;
  color: #d7f5e5;
}

.grid-2 {
  display: grid;
  gap: 1rem;
}
@media (min-width: 640px) {
  .grid-2 { grid-template-columns: 1fr 1fr; }
}
.grid-2 > div {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: .85rem 1rem;
}

details {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: .7rem 1rem;
  margin: .55rem 0;
}
summary {
  cursor: pointer;
  font-weight: 600;
  color: #fff;
}
details p { margin: .65rem 0 .25rem; color: #d5e6ef; }

a { color: var(--accent); }
a:hover { text-decoration-thickness: 2px; }

.contact {
  margin-top: 2rem;
  padding-top: .5rem;
  border-top: 1px solid var(--border);
}

.site-footer {
  margin-top: 2.5rem;
  border-top: 1px solid var(--border);
  background: #050e14;
  color: var(--muted);
  font-size: .92rem;
}
.site-footer .wrap { padding: 1.4rem 0 2rem; }
.site-footer strong { color: #d7e7f0; }

@media (max-width: 420px) {
  body { font-size: 16px; }
  .site-header .wrap { flex-direction: column; gap: .2rem; }
}