:root {
  --bg: #f6f7f9;
  --bg-elevated: #ffffff;
  --ink: #15202b;
  --ink-muted: #5b6775;
  --line: #d9e2e8;
  --accent: #0f6e56;
  --accent-soft: #e6f4ef;
  --warning-bg: #fff7e8;
  --warning-ink: #7a4b00;
  --warning-line: #f0d7a3;
  --shadow: 0 1px 2px rgba(21, 32, 43, 0.04), 0 8px 24px rgba(21, 32, 43, 0.06);
  --radius: 12px;
  --max: 1100px;
  --toc-width: 250px;
  --header-h: 72px;
  --font: "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 16px);
}

body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background:
    radial-gradient(1200px 480px at 10% -10%, #e8f2ee 0%, transparent 55%),
    radial-gradient(900px 420px at 100% 0%, #e9eef5 0%, transparent 50%),
    var(--bg);
  line-height: 1.65;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

img {
  max-width: 100%;
}

a {
  color: var(--accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
}

a:hover {
  color: #0b5743;
}

a:focus-visible,
.skip-link:focus {
  outline: 3px solid rgba(15, 110, 86, 0.45);
  outline-offset: 2px;
}

code {
  font-family: var(--mono);
  font-size: 0.9em;
  background: #eef2f6;
  border: 1px solid #e1e7ee;
  border-radius: 4px;
  padding: 0.1em 0.35em;
}

.skip-link {
  position: absolute;
  left: 12px;
  top: -48px;
  background: var(--ink);
  color: #fff;
  padding: 8px 12px;
  border-radius: 6px;
  z-index: 1000;
}

.skip-link:focus {
  top: 12px;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(10px);
  background: rgba(246, 247, 249, 0.88);
  border-bottom: 1px solid rgba(217, 226, 232, 0.9);
}

.header-inner {
  min-height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.85rem;
}

.brand-mark {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background:
    linear-gradient(145deg, #127a5f 0%, #0f6e56 55%, #0c4f3e 100%);
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.15);
  flex: 0 0 auto;
}

.brand-name {
  margin: 0;
  font-weight: 700;
  letter-spacing: -0.02em;
  font-size: 1.05rem;
}

.brand-tag {
  margin: 0.1rem 0 0;
  color: var(--ink-muted);
  font-size: 0.85rem;
}

.header-nav a {
  font-weight: 600;
  text-decoration: none;
  color: var(--ink);
  padding: 0.4rem 0.7rem;
  border-radius: 8px;
}

.header-nav a:hover {
  background: var(--accent-soft);
  color: var(--accent);
}

.layout {
  display: grid;
  grid-template-columns: var(--toc-width) minmax(0, 1fr);
  gap: 2rem;
  padding: 2rem 0 4rem;
  align-items: start;
}

.toc {
  position: sticky;
  top: calc(var(--header-h) + 16px);
  max-height: calc(100vh - var(--header-h) - 32px);
  overflow: auto;
  background: var(--bg-elevated);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1rem 1rem 1.1rem;
}

.toc-title {
  margin: 0 0 0.75rem;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-muted);
}

.toc ol {
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: toc;
}

.toc li {
  counter-increment: toc;
  margin: 0;
}

.toc a {
  display: block;
  text-decoration: none;
  color: var(--ink-muted);
  font-size: 0.9rem;
  line-height: 1.35;
  padding: 0.42rem 0.45rem;
  border-radius: 6px;
}

.toc a::before {
  content: counter(toc) ". ";
  color: #8a95a3;
  font-variant-numeric: tabular-nums;
}

.toc a:hover {
  background: var(--accent-soft);
  color: var(--accent);
}

.content {
  background: var(--bg-elevated);
  border: 1px solid var(--line);
  border-radius: calc(var(--radius) + 2px);
  box-shadow: var(--shadow);
  padding: clamp(1.4rem, 2.5vw, 2.4rem);
}

.hero {
  margin-bottom: 1.5rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--line);
}

.hero h1 {
  margin: 0 0 0.75rem;
  font-size: clamp(1.8rem, 3vw, 2.35rem);
  line-height: 1.2;
  letter-spacing: -0.03em;
}

.lede {
  margin: 0;
  color: var(--ink-muted);
  font-size: 1.05rem;
  max-width: 62ch;
}

section {
  padding: 1.35rem 0;
  border-bottom: 1px solid #eef2f6;
}

section:last-of-type {
  border-bottom: 0;
}

h2 {
  margin: 0 0 0.75rem;
  font-size: 1.25rem;
  letter-spacing: -0.02em;
  line-height: 1.3;
}

p,
ul {
  margin: 0 0 0.9rem;
  color: #243140;
}

ul {
  padding-left: 1.2rem;
}

li + li {
  margin-top: 0.35rem;
}

.callout {
  border-radius: 10px;
  padding: 0.9rem 1rem;
  margin: 0 0 1rem;
}

.callout p {
  margin: 0;
}

.callout-warning {
  background: var(--warning-bg);
  border: 1px solid var(--warning-line);
  color: var(--warning-ink);
}

.placeholder {
  background: #ffe8a8;
  color: #5c3b00;
  padding: 0.1em 0.35em;
  border-radius: 4px;
  border: 1px dashed #d4a84b;
}

.contact-line {
  font-size: 1.05rem;
}

.doc-footer {
  margin-top: 2rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--line);
}

.doc-footer p {
  margin: 0 0 0.35rem;
}

.muted {
  color: var(--ink-muted);
  font-size: 0.92rem;
}

@media (max-width: 900px) {
  .layout {
    grid-template-columns: 1fr;
    gap: 1.25rem;
    padding-top: 1.25rem;
  }

  .toc {
    position: static;
    max-height: none;
  }

  .toc ol {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.15rem 0.75rem;
  }
}

@media (max-width: 560px) {
  .toc ol {
    grid-template-columns: 1fr;
  }

  .brand-tag {
    display: none;
  }

  body {
    font-size: 15.5px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}