:root {
  --ink: #18222d;
  --muted: #637381;
  --paper: #f7f8f4;
  --line: #d7dde5;
  --rail: #17212b;
  --teal: #0f766e;
  --gold: #b7791f;
  --surface: #ffffff;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font: 16px/1.55 "Segoe UI", Arial, sans-serif;
}
a { color: #155e75; }
.layout {
  min-height: 100vh;
  display: grid;
  grid-template-columns: 56px minmax(210px, 260px) minmax(0, 1fr);
}
.rail {
  position: sticky;
  top: 0;
  height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: .7rem;
  padding: .7rem .45rem;
  background: var(--rail);
  z-index: 5;
}
.rail-logo {
  width: 40px;
  height: 40px;
}
.rail-toggle,
.rail-link {
  width: 38px;
  height: 38px;
  border-radius: 8px;
  border: 1px solid rgba(255,255,255,.18);
  display: grid;
  place-items: center;
  color: #fff;
  background: #243343;
  text-decoration: none;
  cursor: pointer;
}
.rail-link.active,
.rail-toggle:hover,
.rail-link:hover {
  background: var(--teal);
}
.side {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow: auto;
  padding: 1.1rem;
  border-right: 1px solid var(--line);
  background: #fbfcfa;
}
.side strong {
  display: block;
  margin: 0 0 1rem;
  font-size: 1.15rem;
}
.side a {
  display: block;
  padding: .55rem .65rem;
  border-radius: 8px;
  color: var(--ink);
  text-decoration: none;
}
.side a:hover {
  background: #e8f3f1;
  color: #0f4f4a;
}
main {
  min-width: 0;
  padding: clamp(.75rem, 2vw, 1.5rem) clamp(1rem, 3vw, 2.5rem) 2.5rem;
}
section {
  max-width: 1020px;
  padding: 1.1rem 0;
  border-bottom: 1px solid var(--line);
  scroll-margin-top: .75rem;
}
.intro {
  min-height: auto;
  display: flex;
  flex-direction: column;
  gap: .9rem;
  align-items: flex-start;
  justify-content: flex-start;
  padding-top: .6rem;
}
.product-logo {
  width: 116px;
  height: 116px;
  flex: 0 0 auto;
}
.intro-copy {
  width: min(100%, 820px);
  min-width: 0;
}
h1 {
  margin: 0;
  font-size: clamp(2.35rem, 5.6vw, 4.15rem);
  line-height: 1;
  letter-spacing: 0;
  overflow-wrap: normal;
}
h2 {
  margin: 0 0 .6rem;
  font-size: clamp(1.5rem, 3vw, 2.2rem);
  letter-spacing: 0;
}
h3 {
  margin: 0 0 .3rem;
  letter-spacing: 0;
}
p {
  width: min(100%, 75ch);
  margin: 0 0 .75rem;
}
.actions {
  display: flex;
  flex-wrap: wrap;
  gap: .55rem;
}
.actions a {
  min-height: 38px;
  display: inline-flex;
  align-items: center;
  white-space: nowrap;
  padding: .45rem .8rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  text-decoration: none;
}
.actions a:first-child {
  border-color: var(--teal);
  background: var(--teal);
  color: #fff;
}
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: .75rem;
}
.feature-grid article {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  padding: .9rem;
}
body.nav-collapsed .layout {
  grid-template-columns: 56px 0 minmax(0, 1fr);
}
body.nav-collapsed .side {
  display: none;
}
@media (max-width: 760px) {
  .layout {
    grid-template-columns: 48px minmax(0, 1fr);
  }
  .side {
    position: fixed;
    left: 48px;
    top: 0;
    bottom: 0;
    width: min(82vw, 300px);
    z-index: 10;
    box-shadow: 0 12px 28px rgba(15, 23, 42, .22);
  }
  body.nav-collapsed .layout {
    grid-template-columns: 48px minmax(0, 1fr);
  }
  .intro {
    min-height: auto;
  }
  .product-logo {
    width: 96px;
    height: 96px;
  }
}