:root {
  --ink: #1d1d1f;
  --soft: #3f3f44;
  --muted: #6d6d72;
  --line: #e4e4e8;
  --paper: #f7f7f9;
  --card: #ffffff;
  --blue: #0071e3;
  --blue-ink: #004ea3;
  --blue-soft: #eaf3fc;
  --ok: #2f6b4f;
  --ok-soft: #e7f4ec;
  --mid: #8a5a12;
  --mid-soft: #fff4df;
  --hard: #8a3d2b;
  --hard-soft: #fbecea;
  --shadow: 0 18px 40px rgba(23, 23, 25, .06);
  --radius: 12px;
  --nav-h: 58px;
  --sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; background: var(--paper); }
body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 8% -8%, rgba(213, 231, 247, .55), transparent 26rem),
    radial-gradient(circle at 96% 12%, rgba(250, 231, 217, .34), transparent 24rem),
    var(--paper);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 40;
  pointer-events: none;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.035'/%3E%3C/svg%3E");
}
p, h1, h2, h3, h4, ul, ol, dl { margin: 0; }
h1, h2, h3, h4 {
  overflow-wrap: anywhere;
  word-break: break-word;
  letter-spacing: -.03em;
  font-weight: 650;
  line-height: 1.2;
}
a { color: var(--blue-ink); text-underline-offset: 3px; }
code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: .9em;
  background: #eeeef0;
  padding: .12em .4em;
  border-radius: 6px;
}
:focus-visible { outline: 2px solid var(--blue); outline-offset: 2px; }
button { font: inherit; }

.progress {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 30;
  height: 2px;
  width: 100%;
  transform: scaleX(0);
  transform-origin: left;
  background: var(--blue);
  animation: read-progress linear;
  animation-timeline: scroll();
}
@keyframes read-progress {
  from { transform: scaleX(0); }
  to { transform: scaleX(1); }
}

.bar {
  position: relative;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  height: var(--nav-h);
  padding: 0 20px;
  background: #f7f7f9;
  border-bottom: 1px solid rgba(228, 228, 232, .8);
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  text-decoration: none;
  font-size: 14px;
  font-weight: 700;
}
.brand img {
  width: 28px;
  height: 28px;
  border: 1px solid var(--line);
  border-radius: 50%;
  object-fit: cover;
}
.bar-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}
.bar-actions a,
.toc-btn {
  display: inline-flex;
  align-items: center;
  min-height: 34px;
  padding: 0 12px;
  border-radius: 999px;
  text-decoration: none;
  font-size: 13px;
  font-weight: 650;
}
.bar-actions a,
.toc-btn {
  color: var(--blue-ink);
  border: 1px solid rgba(0, 113, 227, .16);
  background: #fff;
  cursor: pointer;
}
.toc-btn[aria-expanded="true"] {
  border-color: var(--blue);
  background: var(--blue-soft);
}
.toc-btn:active,
.bar-actions a:active { transform: scale(.98); }

.shell {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  display: grid;
  grid-template-columns: 210px minmax(0, 1fr);
  gap: 28px;
  padding: 22px 0 80px;
}

.toc {
  position: sticky;
  top: 18px;
  align-self: start;
  max-height: calc(100dvh - 36px);
  overflow: auto;
  padding: 14px 12px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: #fff;
  box-shadow: 0 10px 28px rgba(23, 23, 25, .04);
}
.toc p {
  margin-bottom: 8px;
  padding: 0 8px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
}
.toc a {
  display: block;
  padding: 8px 10px;
  border-radius: 10px;
  color: #5c5c61;
  text-decoration: none;
  font-size: 13px;
  line-height: 1.45;
}
.toc a:hover {
  background: #f3f7fc;
  color: var(--ink);
}
.toc a.active {
  background: #e7f1fc;
  color: #0058b8;
  font-weight: 650;
}

.paper {
  min-width: 0;
  padding: 28px 34px 48px;
  border: 1px solid rgba(29, 29, 31, .08);
  border-radius: 18px;
  background: var(--card);
  box-shadow: var(--shadow);
}

.doc-head {
  padding-bottom: 22px;
  margin-bottom: 8px;
  border-bottom: 1px solid var(--line);
}
.kicker {
  margin-bottom: 10px;
  color: var(--blue);
  font-size: 13px;
  font-weight: 700;
}
.doc-head h1 {
  margin-bottom: 12px;
  font-size: clamp(28px, 6vw, 42px);
  line-height: 1.2;
  overflow-wrap: anywhere;
  word-break: break-word;
}
.lede {
  max-width: 62ch;
  color: var(--soft);
  font-size: 16px;
  line-height: 1.75;
}
.facts {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  margin-top: 18px;
}
.facts div {
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: #fafafb;
}
.facts dt {
  color: var(--muted);
  font-size: 12px;
}
.facts dd {
  margin: 3px 0 0;
  font-size: 14px;
  font-weight: 650;
}

.paper section {
  padding: 28px 0 8px;
}
.paper h2 {
  margin: 8px 0 14px;
  font-size: 24px;
}
.paper h3 {
  margin: 22px 0 10px;
  font-size: 18px;
}
.paper p + p,
.paper p + ul,
.paper ul + p,
.paper p + ol { margin-top: 12px; }
.paper li + li { margin-top: 6px; }
.paper ul, .paper ol {
  padding-left: 1.15em;
  color: var(--soft);
}
.paper p { color: var(--soft); overflow-wrap: anywhere; max-width: 68ch; }

.note {
  margin-top: 16px;
  padding: 14px 16px;
  border-left: 3px solid var(--blue);
  border-radius: 0 10px 10px 0;
  background: var(--blue-soft);
  color: var(--blue-ink);
}

.qa {
  display: grid;
  gap: 10px;
  margin-top: 16px;
}
.qa article {
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fbfbfc;
}
.qa b {
  display: block;
  margin-bottom: 8px;
  color: var(--ink);
  font-size: 16px;
}
.qa p { max-width: none; }

.layers {
  display: grid;
  grid-template-columns: 64px 1fr;
  gap: 0 16px;
  margin: 18px 0 8px;
}
.layers i {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  color: #fff;
  background: var(--ink);
  font-style: normal;
  font-size: 13px;
  font-weight: 700;
}
.layers strong { display: block; margin-bottom: 4px; color: var(--ink); }
.layers p { max-width: none; }
.layers > div { padding-bottom: 16px; }
.layers > i { position: relative; }
.layers > i:not(:nth-last-of-type(1))::after {
  content: "";
  position: absolute;
  top: 40px;
  left: 19px;
  width: 1px;
  height: calc(100% + 16px);
  background: var(--line);
}

.checks {
  width: 100%;
  margin: 16px 0 0;
  border-collapse: collapse;
  font-size: 14px;
}
.checks th, .checks td {
  padding: 12px 10px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--line);
}
.checks th {
  color: var(--muted);
  font-size: 12px;
  font-weight: 650;
}
.checks td:first-child { font-weight: 700; color: var(--ink); white-space: nowrap; }

.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 16px;
}
.split article {
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fbfbfc;
}
.split h3 { margin: 0 0 8px; }
.split p, .split li { font-size: 14px; }
.split ul { margin-top: 10px; }

.steps {
  display: grid;
  gap: 12px;
  margin-top: 16px;
}
.steps article {
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.steps strong { display: block; margin-bottom: 6px; }

.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 16px 0 12px;
}
.chips button {
  min-height: 34px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #fff;
  color: #55555a;
  cursor: pointer;
}
.chips button.active,
.chips button:hover {
  border-color: var(--ink);
  background: var(--ink);
  color: #fff;
}

.topics { display: grid; gap: 18px; }
.topics[data-filter] .topic-group { display: none; }
.topics[data-filter="all"] .topic-group,
.topics[data-filter="home"] .topic-group[data-cat="home"],
.topics[data-filter="vision"] .topic-group[data-cat="vision"],
.topics[data-filter="agri"] .topic-group[data-cat="agri"],
.topics[data-filter="safe"] .topic-group[data-cat="safe"],
.topics[data-filter="care"] .topic-group[data-cat="care"],
.topics[data-filter="llm"] .topic-group[data-cat="llm"],
.topics[data-filter="iot"] .topic-group[data-cat="iot"] { display: block; }

.topic-group h3 { margin-bottom: 8px; }
.topic-list { display: grid; gap: 8px; }
.topic {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 12px;
  align-items: center;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 10px;
}
.topic span { color: var(--soft); font-size: 14px; line-height: 1.5; }
.lv {
  display: inline-flex;
  align-items: center;
  min-height: 24px;
  padding: 0 8px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 700;
  white-space: nowrap;
}
.lv-easy { color: var(--ok); background: var(--ok-soft); }
.lv-mid { color: var(--mid); background: var(--mid-soft); }
.lv-hard { color: var(--hard); background: var(--hard-soft); }

.flow {
  display: grid;
  gap: 10px;
  margin-top: 16px;
  padding: 0;
  list-style: none;
  counter-reset: flow;
}
.flow li {
  position: relative;
  padding: 14px 16px 14px 52px;
  border: 1px solid var(--line);
  border-radius: 10px;
}
.flow li::before {
  counter-increment: flow;
  content: counter(flow);
  position: absolute;
  left: 14px;
  top: 16px;
  display: grid;
  place-items: center;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  color: #fff;
  background: var(--ink);
  font-size: 12px;
  font-weight: 700;
}
.flow strong { color: var(--ink); }

.pits {
  display: grid;
  gap: 10px;
  margin-top: 16px;
  padding: 0;
  list-style: none;
}
.pits li {
  padding: 14px 16px;
  border-top: 1px solid var(--line);
}
.pits li:first-child { border-top: 0; }
.pits b { display: block; margin-bottom: 4px; color: var(--ink); }

.sensor-table {
  width: 100%;
  margin-top: 14px;
  border-collapse: collapse;
  font-size: 14px;
}
.sensor-table th,
.sensor-table td {
  padding: 11px 8px;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--line);
}
.sensor-table th {
  color: var(--muted);
  font-size: 12px;
}

.end {
  margin-top: 28px;
  padding: 22px;
  border: 1px solid rgba(0, 113, 227, .12);
  border-radius: 14px;
  background: linear-gradient(145deg, #f7fbff, #eef5fc);
}
.end h2 { color: var(--ink); margin-top: 0; }
.end p { color: var(--soft); max-width: none; }
.end a {
  display: inline-flex;
  margin-top: 14px;
  color: var(--blue-ink);
  font-weight: 650;
  text-decoration: none;
}

@media (max-width: 900px) {
  .shell { grid-template-columns: 1fr; }
  .toc { display: none; }
  .toc.open {
    display: block;
    position: fixed;
    inset: var(--nav-h) 12px auto;
    z-index: 25;
    max-height: min(70dvh, 520px);
    padding: 14px 12px;
    border: 1px solid var(--line);
    border-radius: 16px;
    background: #fff;
    box-shadow: 0 18px 40px rgba(23, 23, 25, .12);
  }
  .toc-btn { display: inline-flex; }
  .paper { padding: 22px 18px 36px; }
  .facts, .split { grid-template-columns: 1fr 1fr; }
  .topic { grid-template-columns: 1fr; }
}
@media (min-width: 901px) {
  .toc-btn { display: none; }
}
@media (max-width: 620px) {
  .facts, .split { grid-template-columns: 1fr; }
  .doc-head h1 { max-width: none; font-size: 26px; }
  .checks, .sensor-table { display: block; overflow-x: auto; }
  .shell { width: calc(100% - 20px); }
  .paper { padding: 20px 16px 32px; overflow: hidden; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none !important; }
}

@media print {
  .bar, .toc, .progress, .toc-btn, .chips, .end a { display: none !important; }
  .shell { display: block; width: auto; }
  .paper { border: 0; box-shadow: none; padding: 0; }
}