@font-face {
  font-family: DINPro;
  src: url("https://iridi.com/bitrix/templates/iridi_universal/fonts/DINPro/woff2/DINPro-Light.woff2") format("woff2");
  font-weight: 300;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: DINPro;
  src: url("https://iridi.com/bitrix/templates/iridi_universal/fonts/DINPro/woff2/DINPro.woff2") format("woff2");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: DINPro;
  src: url("https://iridi.com/bitrix/templates/iridi_universal/fonts/DINPro/woff2/DINPro-Medium.woff2") format("woff2");
  font-weight: 500;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: DINPro;
  src: url("https://iridi.com/bitrix/templates/iridi_universal/fonts/DINPro/woff2/DINPro-Bold.woff2") format("woff2");
  font-weight: 700;
  font-style: normal;
  font-display: swap;
}

:root {
  --brand: #0057b7;
  --brand-2: #1c75bc;
  --accent: #ff6600;
  --sky: #0ea2ff;
  --ink: #2c343e;
  --muted: #5c6373;
  --bg: #eff4f9;
  --paper: #ffffff;
  --line: #e1e5ea;
  --on-brand: #ffffff;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: DINPro, "Segoe UI", Helvetica, Arial, sans-serif;
  font-weight: 400;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--brand); }
a:hover { color: var(--accent); }
.wrap { width: min(980px, calc(100% - 40px)); margin: 0 auto; }

header {
  background: var(--brand);
  color: var(--on-brand);
}
.top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 16px 0;
}
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: inherit;
}
.brand img { width: 36px; height: 36px; }
.brand strong { display: block; font-size: 16px; font-weight: 700; letter-spacing: 0.02em; }
.brand small { display: block; color: rgba(255, 255, 255, 0.78); font-size: 12px; font-weight: 400; }
nav { display: flex; gap: 18px; flex-wrap: wrap; font-size: 14px; font-weight: 500; }
nav a { text-decoration: none; color: rgba(255, 255, 255, 0.82); }
nav a:hover, nav a[aria-current="page"] { color: var(--on-brand); }

.hero { padding: 72px 0 28px; }
.kicker {
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--brand);
  margin: 0 0 14px;
}
h1 { font-size: clamp(34px, 5vw, 52px); line-height: 1.12; margin: 0 0 18px; font-weight: 700; }
.lead { font-size: 20px; font-weight: 300; color: var(--muted); max-width: 42rem; }

.section { padding: 18px 0 46px; }
h2 { font-size: 28px; margin: 0 0 14px; font-weight: 700; }
h3 { font-size: 18px; margin: 0 0 8px; font-weight: 500; }
p { margin: 0 0 14px; }
.prose p, .prose li { font-size: 17px; font-weight: 400; }

.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 22px;
}
.card {
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 18px 18px 16px;
}
.card p { color: var(--muted); font-size: 15px; margin: 0; }

.note {
  background: var(--paper);
  border-left: 3px solid var(--accent);
  padding: 16px 18px;
  margin: 22px 0;
  font-size: 15px;
  color: var(--muted);
}

.scheme {
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 22px;
  overflow-x: auto;
}
.scheme svg { width: 100%; height: auto; display: block; }
.caption {
  font-size: 13px;
  color: var(--muted);
  margin-top: 10px;
}

.links { list-style: none; padding: 0; margin: 18px 0 0; }
.links li {
  border-top: 1px solid var(--line);
  padding: 14px 0;
  display: grid;
  gap: 4px;
}
.links li:last-child { border-bottom: 1px solid var(--line); }
.links a { font-weight: 500; text-decoration: none; }
.links span { color: var(--muted); font-size: 14px; }

footer {
  background: var(--brand-2);
  color: var(--on-brand);
  padding: 28px 0 40px;
  font-size: 13px;
}
.foot {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}
footer a { color: inherit; }
footer a:hover { color: #acdaff; }

@media (max-width: 800px) {
  .grid { grid-template-columns: 1fr; }
  .top { flex-direction: column; align-items: flex-start; }
  .hero { padding-top: 40px; }
}