:root {
  --bg: #fbfcf8;
  --paper: #ffffff;
  --ink: #121611;
  --muted: #647067;
  --line: #dce4da;
  --line-strong: #b9c7bb;
  --green: #0b7d4f;
  --green-dark: #064b35;
  --cyan: #dff7ee;
  --red: #b9342a;
  --sand: #f0efe7;
  --shadow: 0 24px 70px rgba(19, 31, 25, 0.12);
  --radius: 8px;
  --max: 1180px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background:
    linear-gradient(90deg, rgba(18, 22, 17, 0.035) 1px, transparent 1px),
    linear-gradient(180deg, rgba(18, 22, 17, 0.035) 1px, transparent 1px),
    var(--bg);
  background-size: 64px 64px;
  color: var(--ink);
  font-family: Inter, -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
  letter-spacing: 0;
}

a {
  color: inherit;
  text-decoration: none;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: min(var(--max), calc(100% - 48px));
  height: 76px;
  margin: 0 auto;
  background: rgba(251, 252, 248, 0.88);
  border-bottom: 1px solid rgba(18, 22, 17, 0.08);
  backdrop-filter: blur(16px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  min-width: 144px;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  background: var(--ink);
  color: white;
  border-radius: 6px;
  font-family: "Noto Serif SC", serif;
  font-size: 24px;
  font-weight: 900;
}

.brand-text {
  font-family: "Noto Serif SC", serif;
  font-size: 22px;
  font-weight: 900;
}

.nav {
  display: flex;
  align-items: center;
  gap: 28px;
  color: #344138;
  font-size: 15px;
  font-weight: 600;
}

.nav a {
  transition: color 0.2s ease;
}

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

.nav-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 86px;
  height: 38px;
  border: 1px solid var(--ink);
  border-radius: 999px;
  font-size: 14px;
  font-weight: 700;
}

.menu-toggle {
  display: none;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(440px, 1fr);
  gap: 72px;
  align-items: center;
  width: min(var(--max), calc(100% - 48px));
  min-height: 560px;
  margin: 0 auto;
  padding: 38px 0 46px;
}

.domain {
  width: max-content;
  margin: 0 0 24px;
  padding-bottom: 7px;
  border-bottom: 3px solid var(--red);
  color: var(--red);
  font-size: 15px;
  font-weight: 800;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 26px;
  font-family: "Noto Serif SC", serif;
  font-size: clamp(72px, 10vw, 132px);
  font-weight: 900;
  line-height: 0.95;
}

.hero-lead {
  max-width: 640px;
  margin-bottom: 34px;
  color: #2d3931;
  font-size: clamp(22px, 2.25vw, 31px);
  font-weight: 600;
  line-height: 1.45;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-bottom: 38px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 24px;
  border-radius: 999px;
  font-size: 15px;
  font-weight: 800;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}

.button:hover {
  transform: translateY(-2px);
}

.button.primary {
  background: var(--ink);
  color: white;
  box-shadow: 0 14px 30px rgba(18, 22, 17, 0.16);
}

.button.primary:hover {
  background: var(--green-dark);
}

.button.secondary {
  border: 1px solid var(--line-strong);
  background: var(--paper);
  color: var(--ink);
}

.button.wide {
  width: 100%;
}

.hero-proof {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 700;
}

.hero-proof span {
  position: relative;
  padding-left: 18px;
}

.hero-proof span::before {
  position: absolute;
  top: 0.55em;
  left: 0;
  width: 7px;
  height: 7px;
  background: var(--green);
  border-radius: 999px;
  content: "";
}

.workbench {
  padding: 18px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 18px;
  box-shadow: var(--shadow);
  transform: rotate(-1deg);
}

.workbench-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 14px 20px;
}

.workbench-top strong {
  display: block;
  font-size: 18px;
  font-weight: 900;
}

.workbench-top span {
  color: var(--muted);
  font-size: 13px;
  font-weight: 700;
}

.workbench-top em {
  padding: 6px 10px;
  background: var(--cyan);
  border-radius: 999px;
  color: var(--green-dark);
  font-size: 12px;
  font-style: normal;
  font-weight: 900;
}

.workbench-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.lab-card {
  min-height: 170px;
  padding: 18px;
  background: #f7f9f3;
  border: 1px solid var(--line);
  border-radius: 12px;
}

.lab-card.tall {
  grid-row: span 2;
  min-height: 352px;
  background:
    linear-gradient(160deg, rgba(11, 125, 79, 0.14), rgba(255, 255, 255, 0) 55%),
    #f7f9f3;
}

.lab-card.dark {
  background: var(--ink);
  color: white;
}

.card-index {
  display: block;
  margin-bottom: 46px;
  color: var(--red);
  font-size: 13px;
  font-weight: 900;
}

.lab-card.dark .card-index {
  color: #ff9d87;
}

.lab-card h2 {
  margin-bottom: 10px;
  font-family: "Noto Serif SC", serif;
  font-size: 28px;
  line-height: 1.15;
}

.lab-card p {
  margin-bottom: 0;
  color: inherit;
  font-size: 15px;
  font-weight: 600;
  line-height: 1.55;
  opacity: 0.78;
}

.progress {
  height: 8px;
  margin-top: 84px;
  overflow: hidden;
  background: rgba(18, 22, 17, 0.1);
  border-radius: 999px;
}

.progress span {
  display: block;
  height: 100%;
  background: var(--green);
  border-radius: inherit;
}

.note-strip {
  display: flex;
  gap: 14px;
  align-items: center;
  margin-top: 12px;
  padding: 16px 18px;
  background: var(--sand);
  border-radius: 12px;
}

.note-strip span {
  color: var(--red);
  font-size: 13px;
  font-weight: 900;
}

.note-strip strong {
  font-size: 15px;
}

.section {
  width: min(var(--max), calc(100% - 48px));
  margin: 0 auto;
  padding: 96px 0;
}

.page-hero {
  padding-top: 72px;
  padding-bottom: 64px;
}

.page-hero h1,
.article-title {
  max-width: 940px;
  margin: 0 0 28px;
  font-family: "Noto Serif SC", serif;
  font-size: clamp(54px, 7vw, 104px);
  font-weight: 900;
  line-height: 1.02;
}

.feature-links {
  padding-top: 64px;
}

.section-heading {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 32px;
  align-items: start;
  margin-bottom: 42px;
}

.section-heading p,
.about-copy p {
  margin: 0;
  color: var(--red);
  font-size: 13px;
  font-weight: 900;
  letter-spacing: 0;
  text-transform: uppercase;
}

.section-heading h2,
.about-copy h2 {
  max-width: 820px;
  margin: 0;
  font-family: "Noto Serif SC", serif;
  font-size: clamp(34px, 4.2vw, 60px);
  font-weight: 900;
  line-height: 1.12;
}

.tool-list {
  border-top: 1px solid var(--ink);
}

.tool-row {
  display: grid;
  grid-template-columns: 74px minmax(0, 1fr) 82px;
  gap: 28px;
  align-items: center;
  padding: 30px 0;
  border-bottom: 1px solid var(--line-strong);
}

.tool-symbol {
  display: grid;
  place-items: center;
  width: 58px;
  height: 58px;
  background: var(--paper);
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  color: var(--green);
  font-family: "Noto Serif SC", serif;
  font-size: 24px;
  font-weight: 900;
}

.tool-row h3 {
  margin-bottom: 7px;
  font-size: 22px;
  font-weight: 900;
}

.tool-row p {
  max-width: 760px;
  margin-bottom: 0;
  color: var(--muted);
  font-size: 16px;
  font-weight: 600;
  line-height: 1.7;
}

.tool-row a {
  justify-self: end;
  color: var(--green);
  font-size: 15px;
  font-weight: 900;
}

.projects-section {
  width: 100%;
  max-width: none;
  padding-right: max(24px, calc((100% - var(--max)) / 2));
  padding-left: max(24px, calc((100% - var(--max)) / 2));
  background: var(--ink);
  color: white;
}

.projects-section .article-title {
  color: white;
}

.page-band {
  min-height: calc(100vh - 148px);
}

.projects-section .section-heading p {
  color: #ff9d87;
}

.project-layout {
  display: grid;
  grid-template-columns: minmax(320px, 0.9fr) minmax(0, 1.1fr);
  gap: 22px;
}

.project-feature,
.project-cases article {
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 14px;
}

.project-feature {
  padding: 34px;
  background: #1d251f;
}

.project-feature span {
  display: block;
  margin-bottom: 78px;
  color: #ff9d87;
  font-size: 13px;
  font-weight: 900;
}

.project-feature h3 {
  max-width: 460px;
  margin-bottom: 16px;
  font-family: "Noto Serif SC", serif;
  font-size: 38px;
  line-height: 1.14;
}

.project-feature p {
  color: rgba(255, 255, 255, 0.72);
  font-size: 17px;
  font-weight: 600;
  line-height: 1.8;
}

.text-link {
  color: #9cf2c8;
  font-size: 15px;
  font-weight: 900;
}

.light-link {
  display: inline-block;
  margin-top: 22px;
  color: var(--green);
}

.project-cases {
  display: grid;
  gap: 14px;
}

.project-cases article {
  padding: 26px;
  background: rgba(255, 255, 255, 0.045);
}

.project-cases strong {
  display: block;
  margin-bottom: 10px;
  font-size: 22px;
  font-weight: 900;
}

.project-cases p {
  margin-bottom: 26px;
  color: rgba(255, 255, 255, 0.68);
  font-size: 16px;
  font-weight: 600;
  line-height: 1.7;
}

.project-cases small {
  color: #9cf2c8;
  font-size: 13px;
  font-weight: 900;
}

.article-list {
  border-top: 1px solid var(--ink);
}

.article-list a {
  display: grid;
  grid-template-columns: 70px minmax(0, 1fr) 110px;
  gap: 22px;
  align-items: center;
  padding: 28px 0;
  border-bottom: 1px solid var(--line-strong);
}

.article-list span {
  color: var(--red);
  font-size: 14px;
  font-weight: 900;
}

.article-list strong {
  font-family: "Noto Serif SC", serif;
  font-size: clamp(22px, 2.6vw, 34px);
  font-weight: 900;
  line-height: 1.25;
}

.article-list em {
  justify-self: end;
  color: var(--muted);
  font-size: 14px;
  font-style: normal;
  font-weight: 900;
}

.long-note {
  padding-top: 28px;
}

.long-note-body {
  max-width: 900px;
  margin-left: 212px;
  padding: 42px 0 10px;
  border-top: 1px solid var(--ink);
}

.long-note-body .note-lead {
  color: #1f2822;
  font-family: "Noto Serif SC", serif;
  font-size: clamp(24px, 3vw, 38px);
  font-weight: 900;
  line-height: 1.35;
}

.long-note-body h3 {
  margin: 54px 0 18px;
  font-family: "Noto Serif SC", serif;
  font-size: clamp(28px, 3vw, 44px);
  font-weight: 900;
  line-height: 1.18;
}

.long-note-body p {
  margin-bottom: 18px;
  color: #334039;
  font-size: 18px;
  font-weight: 600;
  line-height: 1.95;
}

.long-note-body pre {
  margin: 24px 0 28px;
  padding: 22px;
  overflow-x: auto;
  background: #121611;
  border-radius: 10px;
  color: #dff7ee;
  box-shadow: 0 18px 48px rgba(18, 22, 17, 0.16);
}

.long-note-body code {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-size: 13px;
  line-height: 1.75;
  white-space: pre;
}

.note-summary {
  display: grid;
  gap: 10px;
  margin-top: 46px;
  padding: 24px;
  background: var(--sand);
  border-left: 4px solid var(--red);
}

.note-summary strong {
  color: var(--red);
  font-size: 14px;
  font-weight: 900;
}

.note-summary span {
  color: #1f2822;
  font-size: 17px;
  font-weight: 800;
  line-height: 1.8;
}

.note-digest {
  padding-top: 28px;
}

.digest-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.digest-grid article {
  min-height: 268px;
  padding: 28px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 14px;
  box-shadow: 0 14px 40px rgba(19, 31, 25, 0.06);
}

.digest-grid article:target {
  border-color: var(--green);
  box-shadow: 0 18px 52px rgba(11, 125, 79, 0.14);
}

.digest-grid span {
  display: block;
  margin-bottom: 42px;
  color: var(--red);
  font-size: 13px;
  font-weight: 900;
}

.digest-grid h3 {
  margin-bottom: 14px;
  font-family: "Noto Serif SC", serif;
  font-size: clamp(26px, 3vw, 38px);
  line-height: 1.16;
}

.digest-grid p {
  margin-bottom: 0;
  color: #334039;
  font-size: 16px;
  font-weight: 600;
  line-height: 1.8;
}

.manifesto-section {
  padding-top: 28px;
}

.manifesto-list {
  border-top: 1px solid var(--ink);
}

.manifesto-list p {
  display: grid;
  grid-template-columns: 70px 1fr;
  gap: 22px;
  align-items: center;
  margin: 0;
  padding: 30px 0;
  border-bottom: 1px solid var(--line-strong);
  color: #1f2822;
  font-family: "Noto Serif SC", serif;
  font-size: clamp(24px, 3vw, 38px);
  font-weight: 900;
  line-height: 1.22;
}

.manifesto-list p::before {
  color: var(--red);
  font-family: Inter, -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 14px;
  font-weight: 900;
  content: "OPC";
}

.about-section {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 390px;
  gap: 72px;
  align-items: start;
  padding-bottom: 120px;
}

.about-copy p {
  margin-bottom: 22px;
}

.about-panel {
  padding: 28px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 16px;
  box-shadow: 0 18px 50px rgba(19, 31, 25, 0.08);
}

.about-panel p {
  margin-bottom: 26px;
  color: #334039;
  font-size: 16px;
  font-weight: 600;
  line-height: 1.75;
}

.contact-line {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 0;
  border-top: 1px solid var(--line);
}

.contact-line span {
  color: var(--muted);
  font-size: 13px;
  font-weight: 900;
}

.contact-line strong {
  text-align: right;
  font-size: 15px;
}

.about-panel .button {
  margin-top: 22px;
}

.contact-scope {
  margin: 14px 0 0;
  color: var(--muted);
  font-size: 13px;
  font-weight: 700;
  line-height: 1.6;
}

.footer {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  width: min(var(--max), calc(100% - 48px));
  margin: 0 auto;
  padding: 28px 0 44px;
  border-top: 1px solid var(--line-strong);
  color: var(--muted);
  font-size: 14px;
  font-weight: 700;
}

.footer-links {
  display: inline-flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 16px;
}

.reveal {
  opacity: 1;
  transform: none;
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

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

  .button,
  .reveal {
    transition: none;
  }
}

@media (max-width: 920px) {
  .site-header {
    width: calc(100% - 32px);
  }

  .nav,
  .nav-cta {
    display: none;
  }

  .menu-toggle {
    display: inline-grid;
    gap: 6px;
    width: 42px;
    height: 42px;
    place-content: center;
    background: var(--paper);
    border: 1px solid var(--line-strong);
    border-radius: 50%;
  }

  .menu-toggle span {
    width: 18px;
    height: 2px;
    background: var(--ink);
  }

  .site-header.is-open .nav {
    position: absolute;
    top: 74px;
    right: 0;
    left: 0;
    display: grid;
    gap: 0;
    padding: 8px;
    background: var(--paper);
    border: 1px solid var(--line);
    border-radius: 12px;
    box-shadow: var(--shadow);
  }

  .site-header.is-open .nav a {
    padding: 14px 16px;
  }

  .hero {
    grid-template-columns: 1fr;
    gap: 42px;
    width: calc(100% - 32px);
    padding-top: 48px;
  }

  h1 {
    font-size: clamp(68px, 20vw, 108px);
  }

  .workbench {
    transform: none;
  }

  .section {
    width: calc(100% - 32px);
    padding: 72px 0;
  }

  .section-heading,
  .about-section,
  .project-layout,
  .digest-grid,
  .manifesto-list p {
    grid-template-columns: 1fr;
  }

  .projects-section {
    width: 100%;
    padding-right: 16px;
    padding-left: 16px;
  }

  .about-section {
    gap: 34px;
  }

  .long-note-body {
    max-width: none;
    margin-left: 0;
  }
}

@media (max-width: 640px) {
  .site-header {
    height: 68px;
  }

  .brand {
    min-width: 0;
  }

  .brand-mark {
    width: 38px;
    height: 38px;
    font-size: 22px;
  }

  .brand-text {
    font-size: 20px;
  }

  .hero {
    min-height: auto;
    padding-bottom: 64px;
  }

  .hero-lead {
    font-size: 22px;
  }

  .button {
    width: 100%;
  }

  .workbench {
    padding: 12px;
    border-radius: 14px;
  }

  .workbench-grid {
    grid-template-columns: 1fr;
  }

  .lab-card.tall {
    min-height: 270px;
  }

  .progress {
    margin-top: 48px;
  }

  .note-strip {
    align-items: flex-start;
    flex-direction: column;
  }

  .tool-row {
    grid-template-columns: 54px 1fr;
    gap: 18px;
    align-items: start;
  }

  .tool-symbol {
    width: 48px;
    height: 48px;
    font-size: 20px;
  }

  .tool-row a {
    grid-column: 2;
    justify-self: start;
  }

  .project-feature {
    padding: 24px;
  }

  .project-feature span {
    margin-bottom: 48px;
  }

  .project-feature h3 {
    font-size: 32px;
  }

  .article-list a {
    grid-template-columns: 42px 1fr;
    gap: 14px;
  }

  .article-list em {
    grid-column: 2;
    justify-self: start;
  }

  .long-note-body {
    padding-top: 28px;
  }

  .long-note-body p {
    font-size: 16px;
    line-height: 1.85;
  }

  .long-note-body pre {
    padding: 18px;
  }

  .manifesto-list p {
    gap: 10px;
    padding: 24px 0;
  }

  .about-panel {
    padding: 22px;
  }

  .digest-grid article {
    min-height: auto;
    padding: 24px;
  }

  .digest-grid span {
    margin-bottom: 34px;
  }

  .contact-line {
    align-items: flex-start;
    flex-direction: column;
    gap: 5px;
  }

  .contact-line strong {
    text-align: left;
  }

  .footer {
    flex-direction: column;
    align-items: flex-start;
    width: calc(100% - 32px);
  }

  .footer-links {
    justify-content: flex-start;
  }
}