:root {
  color-scheme: light;
  --bg: #f7f5ef;
  --paper: #fffefa;
  --ink: #252a2f;
  --muted: #5f6870;
  --line: #ded8cb;
  --teal: #0f766e;
  --blue: #315da8;
  --clay: #9a4f2e;
  --gold: #b47b18;
  --mint: #e5f4ef;
  --sky: #e8effb;
  --peach: #f6eadf;
  --lemon: #f7f0d2;
}

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font:
    16px/1.72 Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont,
    "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

a {
  color: inherit;
  text-decoration-color: rgba(15, 118, 110, 0.42);
  text-underline-offset: 3px;
}

code {
  padding: 0.12em 0.34em;
  border-radius: 5px;
  background: #ece7da;
  color: #28414f;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 0.92em;
}

pre {
  overflow-x: auto;
  margin: 18px 0 0;
  padding: 18px 20px;
  border: 1px solid #25313d;
  border-radius: 8px;
  background: #252a2f;
  color: #f6f1e6;
  line-height: 1.55;
}

pre code {
  padding: 0;
  background: transparent;
  color: inherit;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  min-height: 66px;
  padding: 12px clamp(16px, 4vw, 42px);
  border-bottom: 1px solid rgba(222, 216, 203, 0.86);
  background: rgba(255, 254, 250, 0.92);
  backdrop-filter: blur(16px);
}

.brand,
nav {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand {
  text-decoration: none;
  font-weight: 780;
}

.brand-mark {
  display: grid;
  width: 42px;
  height: 34px;
  place-items: center;
  border-radius: 8px;
  background: var(--ink);
  color: var(--paper);
  font-size: 0.82rem;
  letter-spacing: 0;
}

nav a {
  color: var(--muted);
  font-size: 0.94rem;
  font-weight: 680;
  text-decoration: none;
}

main {
  width: min(1120px, 100%);
  margin: 0 auto;
  padding: clamp(24px, 4vw, 48px) clamp(16px, 4vw, 36px) 76px;
}

.hero {
  padding: clamp(28px, 6vw, 64px) 0 clamp(26px, 5vw, 50px);
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--teal);
  font-size: 0.78rem;
  font-weight: 820;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2,
h3,
h4,
p {
  margin: 0;
}

h1 {
  max-width: 920px;
  font-size: clamp(2.35rem, 6vw, 5.15rem);
  line-height: 1.04;
  letter-spacing: 0;
}

h2 {
  font-size: clamp(1.75rem, 3vw, 2.55rem);
  line-height: 1.16;
}

h3 {
  margin-top: 28px;
  font-size: 1.35rem;
  line-height: 1.25;
}

h4 {
  font-size: 1rem;
  line-height: 1.35;
}

.lead {
  max-width: 820px;
  margin-top: 20px;
  color: #41505a;
  font-size: clamp(1.04rem, 2vw, 1.23rem);
}

.hero-facts {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 28px;
}

.hero-facts span,
.source-section li {
  border-radius: 8px;
}

.hero-facts span {
  padding: 10px 13px;
  border: 1px solid var(--line);
  background: var(--paper);
  color: var(--muted);
  font-weight: 680;
}

.section {
  padding: clamp(30px, 5vw, 54px) 0;
  border-top: 1px solid var(--line);
}

.section > p,
.section-head + p {
  max-width: 880px;
  margin-top: 16px;
  color: #3f4850;
}

.section-head {
  display: grid;
  gap: 6px;
}

.process,
.layer-diagram,
.ncu-flow,
.cards,
.stat-grid,
.use-loop,
.takeaways {
  margin-top: 22px;
}

.process,
.layer-diagram {
  display: grid;
  align-items: stretch;
  grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr) auto minmax(0, 1fr);
  gap: 12px;
}

.process div,
.layer,
.ncu-flow div,
.cards article,
.stat-grid article,
.use-loop article,
.takeaways p {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--paper);
}

.process div,
.layer {
  padding: 18px;
}

.process strong,
.layer strong,
.ncu-flow b {
  display: block;
  line-height: 1.25;
}

.process span,
.layer p,
.ncu-flow span,
.cards p,
.use-loop p,
.takeaways p,
td {
  color: var(--muted);
}

.process i,
.arrow {
  align-self: center;
  color: var(--clay);
  font-style: normal;
  font-weight: 900;
}

.process i::before {
  content: "→";
}

.stat-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
}

.stat-grid article {
  padding: 18px;
}

.stat-grid b {
  display: block;
  color: var(--clay);
  font-size: clamp(2rem, 4vw, 3.25rem);
  line-height: 1;
}

.stat-grid span {
  display: block;
  margin-top: 8px;
  color: var(--muted);
  font-weight: 680;
}

.layer {
  min-height: 168px;
}

.layer:nth-of-type(1) {
  background: var(--mint);
}

.layer:nth-of-type(3) {
  background: var(--sky);
}

.layer:nth-of-type(5) {
  background: var(--peach);
}

.layer span {
  color: var(--gold);
  font-size: 0.78rem;
  font-weight: 820;
  text-transform: uppercase;
}

.layer strong {
  margin-top: 7px;
  font-size: 1.4rem;
}

.layer p {
  margin-top: 10px;
}

table {
  width: 100%;
  margin: 18px 0 8px;
  border-collapse: collapse;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--paper);
  overflow: hidden;
}

th,
td {
  padding: 13px 14px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

th {
  background: #f1ece2;
  color: #39434c;
  font-size: 0.84rem;
}

tr:last-child td {
  border-bottom: 0;
}

.cards {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

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

.cards article {
  padding: 18px;
}

.cards p {
  margin-top: 8px;
}

.ncu-flow {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 10px;
}

.ncu-flow div {
  min-height: 134px;
  padding: 16px;
  background: linear-gradient(180deg, #fffefa, #f3f0e7);
}

.ncu-flow div:nth-child(2) {
  border-color: #b8d4c9;
}

.ncu-flow div:nth-child(3) {
  border-color: #bbc9e6;
}

.ncu-flow div:nth-child(4) {
  border-color: #e0c5ad;
}

.ncu-flow div:nth-child(5) {
  border-color: #decf91;
}

.ncu-flow span {
  display: block;
  margin-top: 10px;
}

.use-loop {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 12px;
}

.use-loop article {
  position: relative;
  padding: 48px 16px 18px;
}

.use-loop span {
  position: absolute;
  top: 16px;
  left: 16px;
  display: grid;
  width: 26px;
  height: 26px;
  place-items: center;
  border-radius: 50%;
  background: var(--teal);
  color: white;
  font-size: 0.8rem;
  font-weight: 800;
}

.use-loop h3 {
  margin: 0;
  font-size: 1.04rem;
}

.use-loop p {
  margin-top: 8px;
}

.takeaways {
  display: grid;
  gap: 12px;
}

.takeaways p {
  padding: 18px;
  background: #fffefa;
}

.takeaways strong {
  color: #22313a;
}

.source-section ul {
  display: grid;
  gap: 10px;
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
}

.source-section li {
  padding: 12px 14px;
  border: 1px solid var(--line);
  background: var(--paper);
  color: var(--muted);
}

@media (max-width: 940px) {
  .process,
  .layer-diagram,
  .ncu-flow,
  .use-loop,
  .stat-grid,
  .cards.compact {
    grid-template-columns: 1fr 1fr;
  }

  .process i,
  .arrow {
    display: none;
  }

  .ncu-flow {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .use-loop {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 680px) {
  .topbar {
    align-items: flex-start;
    flex-direction: column;
  }

  main {
    padding-bottom: 54px;
  }

  .process,
  .layer-diagram,
  .ncu-flow,
  .use-loop,
  .stat-grid,
  .cards,
  .cards.compact {
    grid-template-columns: 1fr;
  }

  table {
    display: block;
    overflow-x: auto;
    white-space: nowrap;
  }

  pre {
    white-space: pre-wrap;
    word-break: break-word;
  }
}