:root {
  --ink: #15191f;
  --ink-soft: #3d4652;
  --paper: #f6f7f4;
  --paper-strong: #ffffff;
  --paper-muted: #e9ece7;
  --line: #cfd5d0;
  --blue: #2457d6;
  --coral: #e45e42;
  --mint: #2b8a72;
  --sun: #f0b44d;
  --shell: min(1180px, calc(100% - 48px));
  --shadow: 0 24px 60px rgba(21, 25, 31, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family:
    "Microsoft YaHei",
    "PingFang SC",
    "Hiragino Sans GB",
    "Noto Sans CJK SC",
    sans-serif;
  font-size: 16px;
  line-height: 1.7;
  text-rendering: optimizeLegibility;
}

body,
a,
button {
  -webkit-font-smoothing: antialiased;
}

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

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

p,
h1,
h2,
h3,
blockquote,
dl,
dd {
  margin: 0;
}

ol,
ul {
  margin: 0;
  padding: 0;
}

::selection {
  background: var(--sun);
  color: var(--ink);
}

.shell {
  width: var(--shell);
  margin-inline: auto;
}

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

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid rgba(21, 25, 31, 0.12);
  background: rgba(246, 247, 244, 0.94);
  backdrop-filter: blur(14px);
}

.header-inner {
  min-height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 17px;
  font-weight: 800;
  letter-spacing: 0;
  white-space: nowrap;
}

.brand-mark {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  object-fit: cover;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 26px;
  overflow-x: auto;
  scrollbar-width: none;
}

.site-nav::-webkit-scrollbar {
  display: none;
}

.site-nav a {
  position: relative;
  padding: 20px 0 18px;
  color: var(--ink-soft);
  font-size: 14px;
  font-weight: 700;
  white-space: nowrap;
}

.site-nav a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 100%;
  bottom: 13px;
  height: 2px;
  background: var(--coral);
  transition: right 180ms ease;
}

.site-nav a:hover,
.site-nav a:focus-visible {
  color: var(--ink);
}

.site-nav a:hover::after,
.site-nav a:focus-visible::after {
  right: 0;
}

.hero {
  position: relative;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
  background: var(--paper-strong);
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0.45;
  background-image: radial-gradient(circle, rgba(21, 25, 31, 0.12) 1px, transparent 1px);
  background-size: 24px 24px;
}

.hero-grid {
  position: relative;
  min-height: calc(100vh - 68px);
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(360px, 0.95fr);
  align-items: center;
  gap: 72px;
  padding-block: 88px;
}

.hero-copy {
  max-width: 660px;
}

.eyebrow {
  margin-bottom: 18px;
  color: var(--blue);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.12em;
}

.eyebrow-light {
  color: #8fb0ff;
}

.hero h1 {
  max-width: 10ch;
  font-size: 96px;
  line-height: 0.98;
  letter-spacing: 0;
}

.hero-lead {
  max-width: 620px;
  margin-top: 28px;
  color: var(--ink-soft);
  font-size: 20px;
  line-height: 1.85;
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 30px;
}

.hero-tags span {
  padding: 7px 11px;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: rgba(255, 255, 255, 0.82);
  color: var(--ink-soft);
  font-size: 13px;
  font-weight: 700;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin-top: 36px;
}

.primary-link,
.secondary-link {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 18px;
  border: 1px solid var(--ink);
  border-radius: 4px;
  font-size: 14px;
  font-weight: 800;
  transition:
    color 160ms ease,
    background-color 160ms ease,
    transform 160ms ease;
}

.primary-link {
  background: var(--ink);
  color: #fff;
}

.secondary-link {
  background: transparent;
  color: var(--ink);
}

.primary-link:hover,
.primary-link:focus-visible,
.secondary-link:hover,
.secondary-link:focus-visible {
  transform: translateY(-2px);
}

.secondary-link:hover,
.secondary-link:focus-visible {
  background: var(--ink);
  color: #fff;
}

:focus-visible {
  outline: 3px solid rgba(36, 87, 214, 0.35);
  outline-offset: 3px;
}

.hero-visual {
  min-width: 0;
}

.visual-frame {
  position: relative;
  width: min(100%, 520px);
  margin-left: auto;
  padding: 22px;
  overflow: hidden;
  border: 1px solid var(--ink);
  border-radius: 8px;
  background: var(--ink);
  color: #fff;
  box-shadow: var(--shadow);
}

.visual-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.07) 1px, transparent 1px);
  background-size: 44px 44px;
}

.visual-label {
  position: relative;
  z-index: 1;
  display: flex;
  justify-content: space-between;
  color: rgba(255, 255, 255, 0.62);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.12em;
}

.project-mark {
  position: relative;
  z-index: 1;
  width: min(76%, 320px);
  height: auto;
  margin: 34px auto 28px;
  border-radius: 24px;
}

.flow-line {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: auto 1fr auto 1fr auto;
  align-items: center;
  gap: 10px;
  margin-top: 10px;
}

.flow-line span {
  width: 28px;
  height: 28px;
  display: grid;
  place-items: center;
  border: 1px solid rgba(255, 255, 255, 0.38);
  border-radius: 50%;
  color: rgba(255, 255, 255, 0.86);
  font-size: 10px;
  font-weight: 800;
}

.flow-line i {
  height: 1px;
  background: rgba(255, 255, 255, 0.28);
}

.flow-labels {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-top: 10px;
  color: rgba(255, 255, 255, 0.7);
  font-size: 12px;
  text-align: center;
}

.statement {
  border-bottom: 1px solid var(--line);
  background: var(--sun);
}

.statement-inner {
  padding-block: 34px;
}

.statement p {
  max-width: 900px;
  font-size: 22px;
  font-weight: 800;
  line-height: 1.65;
}

.section {
  padding-block: 108px;
}

.section-heading {
  display: grid;
  grid-template-columns: 48px minmax(0, 1fr);
  align-items: baseline;
  gap: 16px;
  margin-bottom: 52px;
  border-bottom: 1px solid var(--line);
  padding-bottom: 18px;
}

.section-heading > span {
  color: var(--coral);
  font-size: 13px;
  font-weight: 900;
}

.section-heading h2 {
  font-size: 42px;
  line-height: 1.15;
  letter-spacing: 0;
}

.about-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(280px, 0.65fr);
  gap: 72px;
  align-items: start;
}

.about-copy {
  max-width: 760px;
}

.about-copy p {
  color: var(--ink-soft);
  font-size: 18px;
  line-height: 2;
}

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

.about-copy strong {
  color: var(--ink);
}

.personal-note {
  padding-top: 24px;
  border-top: 4px solid var(--mint);
}

.note-label {
  color: var(--mint);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0.12em;
}

.personal-note blockquote {
  margin-top: 22px;
  font-size: 24px;
  font-weight: 800;
  line-height: 1.6;
}

.personal-note dl {
  margin-top: 34px;
}

.personal-note dl > div {
  padding-block: 14px;
  border-top: 1px solid var(--line);
}

.personal-note dt {
  color: var(--ink-soft);
  font-size: 12px;
  font-weight: 800;
}

.personal-note dd {
  margin-top: 4px;
  font-size: 14px;
}

.section-project {
  background: var(--ink);
  color: #fff;
}

.project-intro {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 0.7fr);
  gap: 72px;
  align-items: end;
  padding-bottom: 54px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.16);
}

.project-intro h2 {
  max-width: 12ch;
  font-size: 54px;
  line-height: 1.12;
}

.project-intro > p {
  color: rgba(255, 255, 255, 0.7);
  font-size: 17px;
  line-height: 1.9;
}

.project-steps {
  list-style: none;
}

.project-steps li {
  display: grid;
  grid-template-columns: 72px minmax(0, 1fr);
  gap: 24px;
  padding-block: 32px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.16);
}

.step-number {
  color: var(--sun);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0.1em;
}

.project-steps h3 {
  font-size: 25px;
}

.project-steps p {
  max-width: 780px;
  margin-top: 8px;
  color: rgba(255, 255, 255, 0.68);
}

.principles {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 40px;
  margin-top: 58px;
}

.principles article {
  padding-top: 20px;
  border-top: 3px solid var(--blue);
}

.principles article:nth-child(2) {
  border-top-color: var(--coral);
}

.principles article:nth-child(3) {
  border-top-color: var(--mint);
}

.principles article > span {
  color: rgba(255, 255, 255, 0.44);
  font-size: 12px;
  font-weight: 800;
}

.principles h3 {
  margin-top: 12px;
  font-size: 21px;
}

.principles p {
  margin-top: 8px;
  color: rgba(255, 255, 255, 0.66);
  font-size: 15px;
}

.section-notes {
  background: var(--paper-strong);
}

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

.note-entry {
  display: grid;
  grid-template-columns: minmax(150px, 0.25fr) minmax(0, 0.75fr);
  grid-template-areas:
    "meta title"
    "meta body";
  gap: 8px 48px;
  padding-block: 34px;
  border-bottom: 1px solid var(--line);
}

.note-meta {
  grid-area: meta;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 8px;
  color: var(--ink-soft);
  font-size: 12px;
  font-weight: 700;
}

.note-meta span {
  color: var(--coral);
}

.note-entry h3 {
  grid-area: title;
  font-size: 27px;
  line-height: 1.35;
}

.note-entry p {
  grid-area: body;
  max-width: 800px;
  color: var(--ink-soft);
  font-size: 16px;
}

.section-updates {
  background: var(--paper-muted);
}

.updates-grid {
  display: grid;
  grid-template-columns: minmax(220px, 0.35fr) minmax(0, 0.65fr);
  gap: 72px;
  align-items: start;
}

.updates-grid .section-heading {
  display: block;
  margin: 0;
  padding-top: 4px;
}

.updates-grid .section-heading > span {
  display: block;
  margin-bottom: 14px;
}

.updates-grid .section-heading h2 {
  font-size: 38px;
}

.timeline {
  list-style: none;
}

.timeline li {
  display: grid;
  grid-template-columns: 120px minmax(0, 1fr);
  gap: 28px;
  padding-block: 24px;
  border-top: 1px solid rgba(21, 25, 31, 0.22);
}

.timeline li:last-child {
  border-bottom: 1px solid rgba(21, 25, 31, 0.22);
}

.timeline time {
  color: var(--ink-soft);
  font-size: 13px;
  font-weight: 800;
}

.timeline h3 {
  font-size: 20px;
}

.timeline p {
  margin-top: 5px;
  color: var(--ink-soft);
  font-size: 15px;
}

.section-site {
  background: var(--paper-strong);
}

.site-note {
  display: grid;
  grid-template-columns: minmax(220px, 0.35fr) minmax(0, 0.65fr);
  gap: 72px;
  align-items: start;
  padding-top: 34px;
  border-top: 4px solid var(--blue);
}

.site-note h2 {
  font-size: 38px;
}

.site-note > p {
  max-width: 760px;
  color: var(--ink-soft);
  font-size: 18px;
  line-height: 1.95;
}

.site-footer {
  padding-block: 44px;
  background: var(--ink);
  color: rgba(255, 255, 255, 0.72);
}

.footer-grid {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 36px;
}

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

.footer-brand img {
  border-radius: 7px;
}

.footer-brand strong {
  display: block;
  color: #fff;
  font-size: 15px;
}

.footer-brand p {
  font-size: 12px;
}

.footer-legal {
  text-align: right;
  font-size: 13px;
}

.footer-legal p + p {
  margin-top: 8px;
}

.footer-legal a {
  color: #fff;
  text-decoration: underline;
  text-underline-offset: 4px;
}

.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition:
    opacity 520ms ease,
    transform 520ms ease;
}

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

@media (max-width: 980px) {
  :root {
    --shell: min(100% - 36px, 760px);
  }

  .hero-grid {
    min-height: auto;
    grid-template-columns: 1fr;
    gap: 54px;
    padding-block: 72px;
  }

  .hero h1 {
    font-size: 78px;
  }

  .visual-frame {
    margin-inline: 0;
  }

  .about-grid,
  .project-intro,
  .updates-grid,
  .site-note {
    grid-template-columns: 1fr;
    gap: 42px;
  }

  .project-intro h2 {
    max-width: 16ch;
  }

  .principles {
    grid-template-columns: 1fr;
    gap: 28px;
  }
}

@media (max-width: 640px) {
  :root {
    --shell: calc(100% - 28px);
  }

  .header-inner {
    min-height: 62px;
    gap: 14px;
  }

  .brand {
    font-size: 15px;
  }

  .brand-mark {
    width: 32px;
    height: 32px;
  }

  .site-nav {
    gap: 18px;
  }

  .site-nav a {
    padding-block: 17px 15px;
    font-size: 13px;
  }

  .hero-grid {
    padding-block: 54px 66px;
  }

  .hero h1 {
    font-size: 58px;
  }

  .hero-lead {
    font-size: 17px;
    line-height: 1.8;
  }

  .hero-actions {
    flex-direction: column;
  }

  .primary-link,
  .secondary-link {
    width: 100%;
  }

  .visual-frame {
    padding: 16px;
  }

  .project-mark {
    width: min(82%, 260px);
    margin-block: 26px 22px;
  }

  .statement p {
    font-size: 18px;
  }

  .section {
    padding-block: 72px;
  }

  .section-heading {
    grid-template-columns: 36px minmax(0, 1fr);
    margin-bottom: 36px;
  }

  .section-heading h2,
  .updates-grid .section-heading h2,
  .site-note h2 {
    font-size: 32px;
  }

  .about-copy p,
  .site-note > p {
    font-size: 16px;
    line-height: 1.85;
  }

  .personal-note blockquote {
    font-size: 21px;
  }

  .project-intro h2 {
    font-size: 38px;
  }

  .project-steps li {
    grid-template-columns: 44px minmax(0, 1fr);
    gap: 14px;
    padding-block: 24px;
  }

  .project-steps h3 {
    font-size: 21px;
  }

  .note-entry {
    grid-template-columns: 1fr;
    grid-template-areas:
      "meta"
      "title"
      "body";
    gap: 8px;
    padding-block: 28px;
  }

  .note-meta {
    flex-direction: row;
    gap: 12px;
  }

  .note-entry h3 {
    font-size: 22px;
  }

  .timeline li {
    grid-template-columns: 1fr;
    gap: 8px;
  }

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

  .footer-legal {
    text-align: left;
  }
}

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

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }

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