:root {
  --bg: #16120e;
  --bg-2: #1d1813;
  --panel: #221c16;
  --line: rgba(255, 236, 210, 0.12);
  --text: #f6efe4;
  --muted: #c9bba8;
  --primary: #4285f4;
  --primary-soft: rgba(66, 133, 244, 0.16);
  --warn: #f59e0b;
  --warn-bg: rgba(245, 158, 11, 0.1);
  --info: #60a5fa;
  --info-bg: rgba(96, 165, 250, 0.1);
  --note: #34d399;
  --note-bg: rgba(52, 211, 153, 0.1);
  --tip: #a78bfa;
  --tip-bg: rgba(167, 139, 250, 0.1);
  --shadow: 0 18px 40px rgba(0, 0, 0, 0.28);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  min-height: 100%;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.65 "IBM Plex Sans", "Segoe UI", system-ui, sans-serif;
}

body {
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
  background-size: 42px 42px;
}

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 1.25rem;
  border-bottom: 1px solid var(--line);
  background: rgba(22, 18, 14, 0.92);
  backdrop-filter: blur(16px);
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  color: inherit;
  text-decoration: none;
}

.brand img {
  height: 36px;
  width: auto;
  display: block;
}

.brand-name {
  font-weight: 650;
  letter-spacing: -0.02em;
}

.main-link {
  display: inline-flex;
  align-items: center;
  padding: 0.55rem 0.9rem;
  border-radius: 999px;
  background: var(--primary);
  color: #fff;
  font-weight: 600;
  text-decoration: none;
}

.layout {
  display: grid;
  grid-template-columns: 260px minmax(0, 1fr);
  max-width: 1180px;
  margin: 0 auto;
}

.sidebar {
  padding: 1.5rem 1.1rem;
  border-right: 1px solid var(--line);
}

.nav-label {
  margin: 0 0 0.7rem;
  color: var(--muted);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  padding: 0.7rem 0.8rem;
  border-radius: 12px;
  background: var(--primary-soft);
  color: var(--text);
  text-decoration: none;
  font-weight: 600;
}

.content {
  padding: 2rem 1.5rem 4rem;
}

.crumb {
  color: var(--muted);
  font-size: 0.88rem;
  margin-bottom: 1rem;
}

h1, h2, h3 { line-height: 1.25; letter-spacing: -0.02em; }
h1 { font-size: 2.15rem; margin: 0 0 0.6rem; }
h2 { font-size: 1.35rem; margin: 2.2rem 0 0.8rem; }
h3 { font-size: 1.08rem; margin: 1.4rem 0 0.55rem; }

p, li { color: var(--text); }
.lede { font-size: 1.05rem; color: #efe6d8; }

hr {
  border: 0;
  border-top: 1px solid var(--line);
  margin: 1.8rem 0;
}

ul { padding-left: 1.2rem; }
li { margin: 0.35rem 0; }

.callout {
  border: 1px solid var(--line);
  border-left: 4px solid var(--info);
  background: var(--info-bg);
  border-radius: 14px;
  padding: 0.95rem 1rem;
  margin: 1rem 0;
}

.callout.warn { border-left-color: var(--warn); background: var(--warn-bg); }
.callout.note { border-left-color: var(--note); background: var(--note-bg); }
.callout.tip { border-left-color: var(--tip); background: var(--tip-bg); }
.callout h3 { margin: 0 0 0.4rem; font-size: 1rem; }

.cards {
  display: grid;
  gap: 0.85rem;
  margin: 1rem 0;
}

.cards.cols-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.cards.cols-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }

.card {
  display: block;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 1rem;
  color: inherit;
  text-decoration: none;
  box-shadow: var(--shadow);
}

.card:hover { border-color: rgba(66, 133, 244, 0.45); text-decoration: none; }
.card strong { display: block; margin-bottom: 0.35rem; }
.card span { color: var(--muted); font-size: 0.95rem; }

details {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 0.85rem 1rem;
  margin: 0.6rem 0;
}

summary { cursor: pointer; font-weight: 650; }

.steps { counter-reset: step; margin: 1rem 0; }
.step {
  display: grid;
  grid-template-columns: 2rem 1fr;
  gap: 0.8rem;
  margin: 0.9rem 0;
}
.step::before {
  counter-increment: step;
  content: counter(step);
  width: 2rem;
  height: 2rem;
  border-radius: 999px;
  display: grid;
  place-items: center;
  background: var(--primary);
  color: #fff;
  font-weight: 700;
}
.step h3 { margin: 0 0 0.25rem; }

.tabs { margin: 1rem 0; }
.tab-bar { display: flex; gap: 0.4rem; flex-wrap: wrap; }
.tab-btn {
  border: 1px solid var(--line);
  background: transparent;
  color: var(--text);
  border-radius: 999px;
  padding: 0.45rem 0.8rem;
  cursor: pointer;
}
.tab-btn.active { background: var(--primary); border-color: var(--primary); }
.tab-panel {
  display: none;
  margin-top: 0.8rem;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 1rem;
}
.tab-panel.active { display: block; }

.footer {
  border-top: 1px solid var(--line);
  padding: 1.2rem;
  color: var(--muted);
  text-align: center;
  font-size: 0.9rem;
}

@media (max-width: 860px) {
  .layout { grid-template-columns: 1fr; }
  .sidebar { display: none; }
  .cards.cols-2, .cards.cols-3 { grid-template-columns: 1fr; }
  .brand-name { display: none; }
}