:root {
  --paper: #f4f7f4;
  --surface: #ffffff;
  --ink: #18231f;
  --muted: #5f6d67;
  --line: #cfd9d4;
  --green: #23624f;
  --blue: #326fa5;
  --coral: #d65c45;
  --yellow: #e7ad35;
  --header-height: 72px;
  --content: 1160px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: "Noto Sans SC", "Microsoft YaHei", "PingFang SC", system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.75;
  letter-spacing: 0;
}

img {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 100;
  padding: 8px 12px;
  background: var(--ink);
  color: #fff;
  transform: translateY(-160%);
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  height: var(--header-height);
  border-bottom: 1px solid rgba(24, 35, 31, 0.12);
  background: rgba(248, 251, 249, 0.94);
  backdrop-filter: blur(16px);
}

.nav-shell {
  width: min(var(--content), calc(100% - 40px));
  height: 100%;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  text-decoration: none;
  font-weight: 800;
  white-space: nowrap;
}

.brand-mark {
  width: 25px;
  height: 25px;
  position: relative;
  display: inline-block;
  border: 2px solid var(--green);
  border-radius: 50%;
}

.brand-mark::before,
.brand-mark::after {
  content: "";
  position: absolute;
  top: 50%;
  height: 2px;
  background: var(--coral);
  transform: translateY(-50%);
}

.brand-mark::before {
  left: -7px;
  width: 9px;
}

.brand-mark::after {
  right: -7px;
  width: 9px;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 6px;
}

.site-nav a {
  padding: 8px 13px;
  border-bottom: 2px solid transparent;
  color: var(--muted);
  font-size: 14px;
  font-weight: 650;
  text-decoration: none;
}

.site-nav a:hover,
.site-nav a[aria-current="page"] {
  border-color: var(--green);
  color: var(--ink);
}

.menu-toggle {
  width: 42px;
  height: 42px;
  display: none;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: var(--surface);
  color: var(--ink);
  font-size: 22px;
  cursor: pointer;
}

.hero {
  min-height: 520px;
  height: min(720px, calc(100svh - 112px));
  position: relative;
  display: grid;
  align-items: center;
  overflow: hidden;
  background: #dfe9e5 url("hero-lab.webp") 62% center / cover no-repeat;
}

.hero-copy {
  width: min(610px, 54%);
  min-height: 100%;
  padding: clamp(54px, 8vw, 110px) max(24px, calc((100vw - var(--content)) / 2));
  padding-right: clamp(30px, 5vw, 72px);
  display: flex;
  flex-direction: column;
  justify-content: center;
  background: rgba(249, 252, 250, 0.80);
  backdrop-filter: blur(4px);
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--green);
  font-size: 13px;
  font-weight: 800;
  text-transform: uppercase;
}

.hero h1 {
  margin: 0;
  max-width: 7em;
  font-size: clamp(48px, 7vw, 86px);
  line-height: 1.04;
  letter-spacing: 0;
}

.hero-lead {
  max-width: 32em;
  margin: 24px 0 0;
  color: #34453e;
  font-size: clamp(17px, 2vw, 21px);
}

.hero-actions {
  margin-top: 32px;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 14px;
}

.text-link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 8px 0;
  border-bottom: 2px solid var(--green);
  color: var(--ink);
  font-weight: 750;
  text-decoration: none;
}

.text-link.secondary {
  border-color: var(--coral);
  color: var(--muted);
}

.status-band {
  background: var(--ink);
  color: #f4f7f4;
}

.status-inner {
  width: min(var(--content), calc(100% - 40px));
  min-height: 72px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 24px;
}

.status-label {
  color: #9fcbb9;
  font-size: 12px;
  font-weight: 800;
}

.status-topics {
  display: flex;
  gap: 22px;
  flex-wrap: wrap;
  font-size: 14px;
}

.status-date {
  color: #cbd6d1;
  font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
  font-size: 12px;
}

.section {
  padding: clamp(70px, 9vw, 120px) 0;
}

.section.alt {
  background: #eaf0ed;
}

.section-inner {
  width: min(var(--content), calc(100% - 40px));
  margin: 0 auto;
}

.section-heading {
  display: grid;
  grid-template-columns: minmax(220px, 0.7fr) minmax(300px, 1.3fr);
  gap: clamp(28px, 6vw, 84px);
  align-items: end;
  margin-bottom: 48px;
}

.section-heading h2,
.page-title h1 {
  margin: 0;
  font-size: clamp(34px, 5vw, 56px);
  line-height: 1.15;
  letter-spacing: 0;
}

.section-heading p,
.page-title p {
  margin: 0;
  color: var(--muted);
  font-size: 17px;
}

.learning-path {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-top: 1px solid var(--line);
}

.path-item {
  padding: 28px 28px 8px 0;
  border-right: 1px solid var(--line);
}

.path-item + .path-item {
  padding-left: 28px;
}

.path-item:last-child {
  border-right: 0;
}

.path-index {
  color: var(--coral);
  font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
  font-size: 12px;
  font-weight: 800;
}

.path-item h3 {
  margin: 14px 0 8px;
  font-size: 21px;
}

.path-item p {
  margin: 0;
  color: var(--muted);
}

.article-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}

.article-card {
  min-height: 300px;
  padding: 24px;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--surface);
  text-decoration: none;
  transition: transform 160ms ease, border-color 160ms ease;
}

.article-card:hover {
  transform: translateY(-3px);
  border-color: var(--green);
}

.article-meta {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  color: var(--muted);
  font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
  font-size: 11px;
}

.article-card h3 {
  margin: 38px 0 12px;
  font-size: 23px;
  line-height: 1.35;
}

.article-card p {
  margin: 0;
  color: var(--muted);
}

.article-arrow {
  margin-top: auto;
  padding-top: 28px;
  color: var(--green);
  font-weight: 800;
}

.image-band {
  min-height: 500px;
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  background: var(--ink);
  color: #f6f8f7;
}

.image-band-media img {
  width: 100%;
  height: 100%;
  min-height: 500px;
  object-fit: cover;
}

.image-band-copy {
  padding: clamp(48px, 7vw, 92px);
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.image-band-copy h2 {
  margin: 0;
  font-size: clamp(32px, 4vw, 52px);
  line-height: 1.18;
}

.image-band-copy p {
  margin: 20px 0 0;
  color: #c9d5d0;
}

.image-band-copy .text-link {
  width: fit-content;
  margin-top: 28px;
  color: #fff;
  border-color: var(--yellow);
}

.page-main {
  min-height: calc(100vh - var(--header-height));
}

.page-title {
  width: min(var(--content), calc(100% - 40px));
  margin: 0 auto;
  padding: clamp(64px, 9vw, 112px) 0 48px;
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 70px;
  align-items: end;
}

.page-title p {
  max-width: 32em;
}

.feature-image {
  width: min(1320px, calc(100% - 40px));
  margin: 0 auto;
  aspect-ratio: 16 / 7;
  overflow: hidden;
  border-radius: 6px;
}

.feature-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.notes-layout {
  width: min(var(--content), calc(100% - 40px));
  margin: 0 auto;
  padding: 80px 0 120px;
  display: grid;
  grid-template-columns: 230px minmax(0, 760px);
  justify-content: space-between;
  gap: 72px;
}

.notes-toc {
  position: sticky;
  top: 104px;
  align-self: start;
  padding-top: 8px;
}

.notes-toc strong {
  display: block;
  margin-bottom: 14px;
  font-size: 13px;
}

.notes-toc a {
  display: block;
  padding: 8px 0;
  border-bottom: 1px solid var(--line);
  color: var(--muted);
  font-size: 13px;
  text-decoration: none;
}

.notes-toc a:hover {
  color: var(--green);
}

.prose article {
  padding: 0 0 74px;
  margin-bottom: 74px;
  border-bottom: 1px solid var(--line);
  scroll-margin-top: 100px;
}

.prose article:last-child {
  margin-bottom: 0;
}

.prose h2 {
  margin: 0 0 18px;
  font-size: clamp(28px, 4vw, 42px);
  line-height: 1.25;
}

.prose h3 {
  margin: 34px 0 10px;
  font-size: 20px;
}

.prose p {
  margin: 0 0 20px;
  color: #34433d;
}

.prose blockquote {
  margin: 30px 0;
  padding: 18px 0 18px 24px;
  border-left: 4px solid var(--yellow);
  color: var(--ink);
  font-size: 19px;
  font-weight: 650;
}

.prose pre {
  margin: 28px 0;
  padding: 20px;
  overflow-x: auto;
  border-radius: 5px;
  background: #1d2924;
  color: #e9f2ee;
  font: 13px/1.7 ui-monospace, "SFMono-Regular", Consolas, monospace;
}

.project-grid {
  width: min(var(--content), calc(100% - 40px));
  margin: 0 auto;
  padding: 80px 0 120px;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.project-card {
  min-height: 360px;
  padding: 30px;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--surface);
}

.project-card:first-child {
  grid-column: span 2;
  min-height: 320px;
  background: #e3efe9;
}

.project-type {
  color: var(--green);
  font-size: 12px;
  font-weight: 800;
}

.project-card h2 {
  margin: 24px 0 12px;
  font-size: clamp(26px, 3vw, 38px);
  line-height: 1.25;
}

.project-card p {
  margin: 0;
  color: var(--muted);
}

.project-tags {
  margin-top: auto;
  padding-top: 36px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  color: #3d5048;
  font: 12px ui-monospace, "SFMono-Regular", Consolas, monospace;
}

.principles {
  width: min(var(--content), calc(100% - 40px));
  margin: 0 auto;
  padding: 80px 0 120px;
  display: grid;
  grid-template-columns: 0.8fr 1.2fr;
  gap: 80px;
}

.about-intro h2 {
  margin: 0 0 18px;
  font-size: 38px;
  line-height: 1.25;
}

.about-intro p {
  color: var(--muted);
}

.principle-list {
  border-top: 1px solid var(--line);
}

.principle {
  display: grid;
  grid-template-columns: 54px 1fr;
  gap: 20px;
  padding: 24px 0;
  border-bottom: 1px solid var(--line);
}

.principle b {
  color: var(--coral);
  font-family: ui-monospace, "SFMono-Regular", Consolas, monospace;
}

.principle h3 {
  margin: 0 0 5px;
  font-size: 19px;
}

.principle p {
  margin: 0;
  color: var(--muted);
}

.site-footer {
  border-top: 1px solid var(--line);
  background: #edf2ef;
}

.footer-inner {
  width: min(var(--content), calc(100% - 40px));
  margin: 0 auto;
  padding: 32px 0;
  display: flex;
  justify-content: space-between;
  gap: 24px;
  color: var(--muted);
  font-size: 12px;
}

.footer-inner p {
  margin: 0;
}

.reveal {
  opacity: 1;
  transform: none;
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

@media (max-width: 820px) {
  .menu-toggle {
    display: inline-grid;
    place-items: center;
  }

  .site-nav {
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    display: none;
    padding: 14px 20px 20px;
    border-bottom: 1px solid var(--line);
    background: #f8fbf9;
  }

  .site-nav.is-open {
    display: grid;
  }

  .site-nav a {
    min-height: 44px;
    display: flex;
    align-items: center;
  }

  .hero {
    min-height: 560px;
    height: calc(100svh - 104px);
    align-items: end;
    background-position: 67% center;
  }

  .hero-copy {
    width: 100%;
    min-height: auto;
    padding: 36px 20px 42px;
    background: rgba(249, 252, 250, 0.88);
  }

  .hero h1 {
    font-size: clamp(46px, 14vw, 66px);
  }

  .status-inner {
    padding: 18px 0;
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .status-date {
    display: none;
  }

  .section-heading,
  .page-title,
  .principles {
    grid-template-columns: 1fr;
    gap: 22px;
  }

  .learning-path,
  .article-list,
  .project-grid {
    grid-template-columns: 1fr;
  }

  .path-item,
  .path-item + .path-item {
    padding: 24px 0;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }

  .article-card {
    min-height: 260px;
  }

  .image-band {
    grid-template-columns: 1fr;
  }

  .image-band-media img {
    min-height: 300px;
    max-height: 420px;
  }

  .image-band-copy {
    padding: 44px 20px 56px;
  }

  .page-title {
    padding-top: 56px;
  }

  .feature-image {
    width: 100%;
    border-radius: 0;
    aspect-ratio: 4 / 3;
  }

  .notes-layout {
    grid-template-columns: 1fr;
    gap: 46px;
    padding-top: 54px;
  }

  .notes-toc {
    position: static;
  }

  .project-card:first-child {
    grid-column: span 1;
  }

  .principles {
    padding-top: 60px;
  }

  .footer-inner {
    flex-direction: column;
  }
}

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

  .reveal,
  .article-card {
    opacity: 1;
    transform: none;
    transition: none;
  }
}