:root {
  --green: #1E8C5A;
  --green-bright: #27AE60;
  --green-dim: rgba(30, 140, 90, 0.14);
  --blue: #1B4F72;
  --blue-deep: #143753;
  --gold: #D4A017;
  --gold-soft: rgba(212, 160, 23, 0.14);
  --ink: #111111;
  --ink-soft: #181818;
  --white: #FFFFFF;
  --grey-050: #F4F6F7;
  --grey-200: #E5E8E8;
  --grey-500: #7F8C8D;
  --grey-700: #2C3E50;
  --font-head: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --font-body: "Noto Serif SC", "Songti SC", "SimSun", "Source Han Serif SC", Georgia, serif;
  --font-mono: "JetBrains Mono", "SF Mono", "Cascadia Code", Consolas, "Courier New", monospace;
  --container: 1200px;
  --header-h: 72px;
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.75;
  color: var(--ink);
  background: var(--white);
  min-height: 100vh;
  overflow-wrap: break-word;
  -webkit-font-smoothing: antialiased;
}

img, svg, video {
  display: block;
  max-width: 100%;
  height: auto;
}

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

button, input, select, textarea {
  font: inherit;
  color: inherit;
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
}

ul, ol {
  list-style: none;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-head);
  font-weight: 900;
  line-height: 1.35;
  color: var(--ink);
}

::selection {
  background: var(--green);
  color: var(--white);
}

:focus-visible {
  outline: 2px solid var(--gold);
  outline-offset: 2px;
}

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

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

.skip-link {
  position: fixed;
  top: 0;
  left: 1rem;
  z-index: 1000;
  padding: 0.75rem 1.25rem;
  background: var(--ink);
  color: var(--white);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  opacity: 0;
  transform: translateY(-100%);
  transition: transform 0.25s ease, opacity 0.25s ease;
}

.skip-link:focus-visible {
  opacity: 1;
  transform: translateY(0);
  outline: 2px solid var(--gold);
  outline-offset: -2px;
}

.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: 2rem;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--ink);
  color: var(--white);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  box-shadow: 0 1px 12px rgba(0, 0, 0, 0.25);
}

.header-topline {
  position: relative;
  height: 4px;
  background: var(--green);
  overflow: hidden;
}

.scroll-progress {
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  width: 100%;
  background: var(--gold);
  transform: scaleX(0);
  transform-origin: left center;
  will-change: transform;
}

.header-inner {
  position: relative;
  height: var(--header-h);
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

.site-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.625rem;
  flex-shrink: 0;
  color: var(--white);
  transition: opacity 0.2s ease;
}

.site-brand:hover {
  opacity: 0.9;
}

.brand-symbol {
  position: relative;
  width: 30px;
  height: 30px;
  flex-shrink: 0;
  background: var(--green);
  clip-path: polygon(12% 0, 88% 0, 100% 12%, 100% 88%, 88% 100%, 12% 100%, 0 88%, 0 12%);
  transition: background 0.25s ease;
}

.brand-symbol::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 50%;
  width: 10px;
  height: 10px;
  background: var(--gold);
  clip-path: polygon(50% 0, 100% 50%, 50% 100%, 0 50%);
  transform: translate(-50%, -50%);
  transition: transform 0.25s ease;
}

.site-brand:hover .brand-symbol {
  background: var(--green-bright);
}

.site-brand:hover .brand-symbol::after {
  transform: translate(-50%, -50%) rotate(45deg);
}

.brand-name {
  font-family: var(--font-head);
  font-size: 1.1875rem;
  font-weight: 900;
  letter-spacing: 0.02em;
  white-space: nowrap;
}

.brand-region {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  color: var(--gold);
  border: 1px solid var(--gold);
  padding: 0.15rem 0.4rem;
  margin-left: 0.25rem;
  white-space: nowrap;
}

.site-nav {
  margin-left: 0.5rem;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.nav-link {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.55rem 0.7rem;
  font-family: var(--font-head);
  font-size: 0.875rem;
  font-weight: 700;
  color: rgba(255, 255, 255, 0.82);
  border-bottom: 2px solid transparent;
  white-space: nowrap;
  transition: color 0.25s ease, border-color 0.25s ease, background 0.25s ease;
}

.nav-index {
  font-family: var(--font-mono);
  font-size: 0.5625rem;
  font-weight: 500;
  line-height: 1;
  color: var(--green-bright);
  background: rgba(30, 140, 90, 0.18);
  padding: 0.2rem 0.32rem;
  border-radius: 2px;
  transition: background 0.25s ease, color 0.25s ease;
}

.nav-link:hover {
  color: var(--white);
  border-bottom-color: var(--green);
}

.nav-link:hover .nav-index {
  background: rgba(30, 140, 90, 0.35);
}

.nav-link[aria-current="page"] {
  color: var(--white);
  border-bottom-color: var(--gold);
}

.nav-link[aria-current="page"] .nav-index {
  background: var(--gold);
  color: var(--ink);
}

.nav-utility {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-shrink: 0;
}

.utility-link {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-head);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  padding: 0.5rem 0.9rem;
  white-space: nowrap;
  transition: color 0.25s ease, background 0.25s ease, border-color 0.25s ease;
}

.utility-download {
  background: var(--green);
  color: var(--white);
  clip-path: polygon(0 0, calc(100% - 10px) 0, 100% 100%, 10px 100%);
}

.utility-download:hover {
  background: var(--green-bright);
  color: var(--white);
}

.utility-legacy {
  color: rgba(255, 255, 255, 0.65);
  border-bottom: 1px dashed rgba(255, 255, 255, 0.35);
}

.utility-legacy:hover {
  color: var(--gold);
  border-bottom-color: var(--gold);
}

.nav-toggle {
  display: none;
  position: relative;
  width: 44px;
  height: 44px;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  background: transparent;
  border: none;
  cursor: pointer;
}

.toggle-line {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--white);
  transition: transform 0.3s ease, opacity 0.3s ease;
}

.nav-toggle[aria-expanded="true"] .toggle-line:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .toggle-line:nth-child(2) {
  opacity: 0;
  transform: translateX(-8px);
}

.nav-toggle[aria-expanded="true"] .toggle-line:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.site-footer {
  position: relative;
  background: var(--ink);
  color: rgba(255, 255, 255, 0.72);
  font-family: var(--font-body);
  font-size: 0.875rem;
  border-top: 4px solid var(--green);
}

.footer-grid {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding: 3.5rem 2rem 3rem;
  display: grid;
  grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr) minmax(0, 1fr) minmax(0, 1.4fr);
  gap: 2.5rem;
}

.footer-block {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  min-width: 0;
}

.footer-brandname {
  font-family: var(--font-head);
  font-size: 1.5rem;
  font-weight: 900;
  color: var(--white);
  letter-spacing: 0.02em;
  line-height: 1.3;
}

.footer-brandname > span {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  font-weight: 500;
  color: var(--gold);
  border: 1px solid var(--gold);
  padding: 0.15rem 0.4rem;
  margin-left: 0.25rem;
  vertical-align: middle;
  letter-spacing: 0.1em;
}

.footer-tagline {
  max-width: 24rem;
  margin-top: 1rem;
  font-size: 0.875rem;
  line-height: 1.9;
  color: rgba(255, 255, 255, 0.55);
}

.footer-trust {
  margin-top: 1.25rem;
  padding-left: 0.75rem;
  border-left: 3px solid var(--green);
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.04em;
  color: var(--green-bright);
}

.footer-title {
  font-family: var(--font-head);
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--white);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  margin-bottom: 1.1rem;
  padding-bottom: 0.6rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
  position: relative;
  width: 100%;
}

.footer-title::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 32px;
  height: 2px;
  background: var(--green);
}

.footer-links li + li {
  margin-top: 0.6rem;
}

.footer-links a {
  display: inline-block;
  color: rgba(255, 255, 255, 0.62);
  transition: color 0.25s ease, padding-left 0.25s ease;
}

.footer-links a:hover {
  color: var(--gold);
  padding-left: 0.5rem;
}

.footer-contact-list {
  display: grid;
  gap: 0.6rem;
  width: 100%;
}

.footer-contact-list li {
  display: grid;
  grid-template-columns: 4em 1fr;
  gap: 0.6rem;
  color: rgba(255, 255, 255, 0.72);
}

.contact-label {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--green-bright);
  padding-top: 0.15em;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  background: #0D0D0D;
}

.footer-bottom-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  padding-top: 1.25rem;
  padding-bottom: 1.25rem;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.05em;
  color: rgba(255, 255, 255, 0.42);
}

.icp {
  color: var(--gold);
}

.footer-note {
  color: rgba(255, 255, 255, 0.35);
}

.back-top {
  position: fixed;
  right: 1.5rem;
  bottom: 1.5rem;
  z-index: 90;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 46px;
  height: 46px;
  background: var(--green);
  color: var(--white);
  clip-path: polygon(0 0, calc(100% - 10px) 0, 100% 100%, 10px 100%);
  opacity: 0;
  visibility: hidden;
  transform: translateY(14px);
  transition: background 0.25s ease, opacity 0.3s ease, transform 0.3s ease, visibility 0.3s ease;
}

.back-top:hover {
  background: var(--green-bright);
}

.back-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-top-arrow {
  font-size: 1.25rem;
  line-height: 1;
  transform: translateY(-1px);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.8rem 1.6rem;
  font-family: var(--font-head);
  font-size: 0.875rem;
  font-weight: 700;
  line-height: 1.2;
  border: 2px solid transparent;
  text-align: center;
  transition: background 0.25s ease, color 0.25s ease, border-color 0.25s ease, transform 0.2s ease;
}

.btn:active {
  transform: translateY(1px);
}

.btn-primary {
  background: var(--green);
  color: var(--white);
  clip-path: polygon(0 0, calc(100% - 12px) 0, 100% 100%, 12px 100%);
}

.btn-primary:hover {
  background: var(--green-bright);
  color: var(--white);
}

.btn-ghost {
  border-color: var(--ink);
  color: var(--ink);
  background: transparent;
}

.btn-ghost:hover {
  background: var(--ink);
  color: var(--white);
}

.section-label {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--green);
}

.section-label::before {
  content: "";
  display: block;
  width: 24px;
  height: 2px;
  background: var(--gold);
}

.meta-index {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--grey-500);
  text-transform: uppercase;
}

.divider-line {
  height: 2px;
  margin: 2rem 0;
  border: none;
  background: linear-gradient(to right, var(--green) 0%, var(--green) 64px, var(--grey-200) 64px, var(--grey-200) 100%);
}

.tag {
  display: inline-block;
  padding: 0.2rem 0.6rem;
  font-family: var(--font-mono);
  font-size: 0.625rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  border: 1px solid var(--grey-200);
  color: var(--grey-700);
  background: var(--white);
}

.tag-accent {
  border-color: var(--green);
  color: var(--green);
  background: var(--green-dim);
}

.tag-gold {
  border-color: var(--gold);
  color: var(--ink);
  background: var(--gold-soft);
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  color: var(--grey-500);
  padding: 1.5rem 0;
}

.breadcrumb li {
  display: inline-flex;
  align-items: center;
}

.breadcrumb a {
  color: var(--grey-700);
  transition: color 0.2s ease;
}

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

.breadcrumb li + li::before {
  content: "→";
  margin: 0 0.5rem;
  color: var(--grey-500);
  font-size: 0.6875rem;
}

.breadcrumb li:last-child {
  color: var(--ink);
  font-weight: 500;
}

.content-body {
  font-family: var(--font-body);
  font-size: 1.0625rem;
  line-height: 1.9;
  color: var(--ink);
  max-width: 46rem;
}

.content-body > * + * {
  margin-top: 1.2em;
}

.content-body h2,
.content-body h3 {
  font-family: var(--font-head);
  font-weight: 900;
  color: var(--ink);
  line-height: 1.3;
}

.content-body h2 {
  font-size: 1.75rem;
  margin-top: 2em;
}

.content-body h3 {
  font-size: 1.3rem;
  margin-top: 1.6em;
}

.content-body a {
  color: var(--green);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.content-body a:hover {
  color: var(--gold);
}

.content-body ul {
  list-style: disc;
  padding-left: 1.5em;
}

.content-body ol {
  list-style: decimal;
  padding-left: 1.5em;
}

.content-body strong {
  font-family: var(--font-head);
  font-weight: 900;
}

.chamfer-panel {
  position: relative;
  padding: 2rem;
  background: var(--grey-050);
  border: 1px solid var(--grey-200);
  clip-path: polygon(0 0, calc(100% - 20px) 0, 100% 20px, 100% 100%, 20px 100%, 0 calc(100% - 20px));
}

.image-frame {
  position: relative;
  display: block;
  overflow: hidden;
  background: var(--grey-050);
  border: 1px solid var(--grey-200);
}

.image-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.4s ease;
}

.image-frame:hover img {
  transform: scale(1.02);
}

.image-frame::before {
  content: "";
  position: absolute;
  z-index: 1;
  top: 0;
  left: 0;
  width: 3px;
  height: 100%;
  background: var(--green);
  pointer-events: none;
}

.image-frame::after {
  content: "";
  position: absolute;
  z-index: 2;
  right: -30px;
  bottom: -30px;
  width: 70px;
  height: 70px;
  background: var(--blue);
  opacity: 0.85;
  transform: rotate(45deg);
  pointer-events: none;
}

.image-frame--wide {
  aspect-ratio: 16 / 9;
}

.image-frame--tall {
  aspect-ratio: 3 / 4;
}

.image-frame--square {
  aspect-ratio: 1 / 1;
}

.step-index {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.25rem;
  height: 2.25rem;
  flex-shrink: 0;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--white);
  background: var(--blue);
  clip-path: polygon(0 0, calc(100% - 8px) 0, 100% 100%, 8px 100%);
}

.grid-2,
.grid-3 {
  display: grid;
  gap: 2rem;
  align-items: start;
}

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

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

@media (max-width: 960px) {
  .container {
    padding-inline: 1.5rem;
  }

  .header-inner {
    gap: 0.9rem;
  }

  .site-brand {
    gap: 0.5rem;
  }

  .nav-toggle {
    display: flex;
    margin-left: auto;
  }

  .nav-utility {
    margin-left: 0;
    gap: 0.4rem;
  }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background: var(--ink-soft);
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    border-bottom: 3px solid var(--green);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity 0.3s ease, transform 0.3s ease, visibility 0.3s ease;
    pointer-events: none;
  }

  .site-nav[data-open] {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
    pointer-events: auto;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 0.75rem 1.5rem 1.25rem;
  }

  .nav-link {
    justify-content: flex-start;
    padding: 0.85rem 0.5rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    border-left: 3px solid transparent;
    font-size: 0.9375rem;
  }

  .nav-link:hover,
  .nav-link[aria-current="page"] {
    background: rgba(30, 140, 90, 0.1);
    border-left-color: var(--green);
  }

  .nav-link[aria-current="page"] {
    border-bottom-color: rgba(255, 255, 255, 0.08);
  }

  .nav-index {
    min-width: 1.75rem;
    text-align: center;
  }

  .footer-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 2rem;
    padding: 3rem 1.5rem 2.5rem;
  }

  .grid-2,
  .grid-3 {
    grid-template-columns: minmax(0, 1fr);
  }
}

@media (max-width: 640px) {
  :root {
    --header-h: 64px;
  }

  .container {
    padding-inline: 1.25rem;
  }

  .header-inner {
    gap: 0.6rem;
  }

  .brand-symbol {
    width: 26px;
    height: 26px;
  }

  .brand-symbol::after {
    width: 8px;
    height: 8px;
  }

  .brand-name {
    font-size: 1rem;
  }

  .brand-region {
    display: none;
  }

  .utility-link {
    padding: 0.42rem 0.7rem;
    font-size: 0.6875rem;
  }

  .utility-download {
    clip-path: polygon(0 0, calc(100% - 7px) 0, 100% 100%, 7px 100%);
  }

  .site-nav .nav-list {
    padding-inline: 1.25rem;
  }

  .footer-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 1.75rem;
    padding: 2.5rem 1.25rem 2rem;
  }

  .footer-bottom-inner {
    flex-direction: column;
    justify-content: center;
    text-align: center;
  }

  .back-top {
    right: 1rem;
    bottom: 1rem;
    width: 42px;
    height: 42px;
  }

  .content-body {
    font-size: 1rem;
  }
}

@media (max-width: 380px) {
  .utility-legacy {
    display: none;
  }
}