:root {
  --color-primary: #0d1b2a;
  --color-secondary: #1b263b;
  --color-accent: #fca311;
  --color-gold: #b8860b;
  --color-silver: #c0c0c0;
  --color-silver-light: #e5e5e5;
  --color-cream: #f4f1de;
  --color-danger: #e63946;
  --color-info: #457b9d;
  --color-black: #000000;
  --color-white: #ffffff;
  --font-sans: 'Source Sans Pro', 'Segoe UI', 'Microsoft YaHei', sans-serif;
  --font-head: 'Noto Sans SC', 'Microsoft YaHei', sans-serif;
  --font-mono: 'IBM Plex Mono', 'Consolas', monospace;
  --container-width: 1200px;
  --radius: 6px;
  --shadow: 0 12px 30px rgba(0, 0, 0, 0.3);
  --transition: 200ms ease;
}

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

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

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
  color: var(--color-cream);
  background-color: var(--color-primary);
  -webkit-font-smoothing: antialiased;
}

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

button {
  font-family: inherit;
}

a {
  color: var(--color-accent);
}

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

h1, h2, h3, h4, h5, h6 {
  margin: 0 0 0.5em;
  font-family: var(--font-head);
  font-weight: 900;
  line-height: 1.15;
  letter-spacing: -0.01em;
  color: var(--color-primary);
}

:focus-visible {
  outline: 3px solid var(--color-accent);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation: none !important;
    transition: none !important;
    scroll-behavior: auto !important;
  }
}

.container {
  width: 100%;
  max-width: var(--container-width);
  margin-inline: auto;
  padding-inline: 24px;
}

@media (max-width: 600px) {
  .container {
    padding-inline: 16px;
  }
}

#main-content {
  background: var(--color-cream);
  color: var(--color-primary);
  min-height: 65vh;
}

#main-content:focus {
  outline: none;
}

.section {
  padding-block: clamp(3rem, 8vw, 6rem);
}

.section--dark {
  background-color: var(--color-primary);
  color: var(--color-cream);
}

.section--dark h1,
.section--dark h2,
.section--dark h3,
.section--dark h4,
.section--dark h5,
.section--dark h6 {
  color: var(--color-cream);
}

.section--dark a:not(.button):not(.link-arrow) {
  color: var(--color-accent);
}

.section--light {
  background-color: var(--color-cream);
  color: var(--color-primary);
}

.section__header {
  margin-bottom: 2rem;
}

.grid {
  display: grid;
  gap: 1.5rem;
}

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

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

@media (max-width: 900px) {
  .grid--two,
  .grid--three {
    grid-template-columns: 1fr;
  }
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

.skip-link {
  position: fixed;
  top: -100%;
  left: 1rem;
  z-index: 200;
  padding: 0.6rem 1rem;
  background: var(--color-accent);
  color: var(--color-primary);
  font-family: var(--font-head);
  font-weight: 700;
  text-decoration: none;
  border-radius: 0 0 var(--radius) var(--radius);
}

.skip-link:focus {
  top: 0;
}

.site-header {
  position: relative;
  z-index: 50;
  background: linear-gradient(180deg, #0d1b2a 0%, #101e30 100%);
  color: var(--color-cream);
}

.site-header::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -6px;
  width: 68%;
  height: 6px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-gold));
  clip-path: polygon(0 0, 100% 0, calc(100% - 24px) 100%, 0 100%);
}

.header-top {
  background: rgba(27, 38, 59, 0.8);
  border-bottom: 1px solid rgba(192, 192, 192, 0.15);
}

.header-top__inner {
  min-height: 40px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.header-top__tagline {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  color: var(--color-silver);
  text-transform: uppercase;
}

.header-quick-navigation {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.header-quick-link {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.05em;
  color: var(--color-silver);
  text-decoration: none;
  padding: 0.4rem 0.6rem;
  border-radius: 2px;
  transition: background-color var(--transition), color var(--transition);
}

.header-quick-link:hover {
  color: var(--color-accent);
  background: rgba(252, 163, 17, 0.1);
}

.header-main {
  background: rgba(13, 27, 42, 0.95);
}

.header-main__inner {
  min-height: 84px;
  display: flex;
  align-items: center;
  gap: 2rem;
  padding-block: 0.75rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--color-cream);
  flex-shrink: 0;
}

.brand__mark {
  width: 32px;
  height: 32px;
  background: linear-gradient(135deg, var(--color-accent) 50%, var(--color-gold) 50%);
  clip-path: polygon(50% 0, 100% 25%, 100% 75%, 50% 100%, 0 75%, 0 25%);
  transition: transform var(--transition);
}

.brand:hover .brand__mark {
  transform: rotate(15deg) scale(1.05);
}

.brand__name {
  font-family: var(--font-head);
  font-weight: 900;
  font-size: 1.35rem;
  letter-spacing: -0.02em;
  line-height: 1.1;
  color: inherit;
  text-transform: uppercase;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 0;
  margin-left: auto;
  background: transparent;
  border: 1px solid rgba(192, 192, 192, 0.35);
  border-radius: var(--radius);
  cursor: pointer;
  flex-shrink: 0;
  transition: border-color var(--transition);
}

.nav-toggle:hover {
  border-color: var(--color-accent);
}

.nav-toggle[aria-expanded="true"] {
  border-color: var(--color-accent);
}

.nav-toggle__bar {
  width: 22px;
  height: 2px;
  background: var(--color-cream);
  display: block;
  transition: transform var(--transition), background-color var(--transition);
}

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

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(2) {
  opacity: 0;
}

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

.site-navigation {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  margin-left: auto;
}

.site-navigation__link {
  position: relative;
  display: inline-block;
  padding: 0.5rem 0.9rem;
  font-family: var(--font-head);
  font-size: 0.95rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--color-silver);
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--transition), background-color var(--transition);
}

.site-navigation__link::after {
  content: "";
  position: absolute;
  left: 0.9rem;
  right: 0.9rem;
  bottom: 2px;
  height: 2px;
  background: var(--color-accent);
  transform: scaleX(0);
  transform-origin: 0 50%;
  transition: transform 180ms ease;
}

.site-navigation__link:hover {
  color: var(--color-white);
}

.site-navigation__link:hover::after,
.site-navigation__link[aria-current="page"]::after {
  transform: scaleX(1);
}

.site-navigation__link[aria-current="page"] {
  color: var(--color-accent);
}

@media (max-width: 960px) {
  .nav-toggle {
    display: flex;
  }

  .site-navigation {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    z-index: 60;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    margin: 0;
    padding: 0.5rem 1rem 1rem;
    background: var(--color-primary);
    border-top: 1px solid rgba(192, 192, 192, 0.2);
    display: none;
    box-shadow: var(--shadow);
  }

  .site-navigation[data-open] {
    display: flex;
  }

  .site-navigation__link {
    padding: 0.9rem 0.75rem;
    border-bottom: 1px solid rgba(192, 192, 192, 0.12);
    font-size: 1rem;
  }

  .site-navigation__link::after {
    display: none;
  }

  .site-navigation__link:last-child {
    border-bottom: none;
  }
}

@media (max-width: 640px) {
  .header-top__tagline {
    display: none;
  }

  .header-quick-navigation {
    justify-content: flex-end;
    width: 100%;
  }

  .header-quick-link {
    font-size: 0.7rem;
    padding: 0.2rem 0.4rem;
  }

  .brand__name {
    font-size: 1.1rem;
  }
}

@media (max-width: 480px) {
  .brand__mark {
    width: 26px;
    height: 26px;
  }

  .brand__name {
    font-size: 0.95rem;
  }
}

.site-footer {
  position: relative;
  background: linear-gradient(180deg, #0d1b2a, #0a1622 100%);
  color: var(--color-silver);
  padding-top: 3.5rem;
  border-top: 4px solid var(--color-gold);
}

.site-footer__inner {
  position: relative;
  display: grid;
  grid-template-columns: 1.4fr 1fr 0.8fr;
  gap: 2.5rem;
  padding-bottom: 2.5rem;
}

.site-footer__inner::before {
  content: "";
  position: absolute;
  top: -4px;
  left: 0;
  width: 40%;
  height: 4px;
  background: var(--color-accent);
  z-index: 2;
}

@media (max-width: 900px) {
  .site-footer__inner {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }
}

.site-footer__brand-name {
  margin: 0 0 0.25rem;
  font-family: var(--font-head);
  font-weight: 900;
  font-size: 1.5rem;
  color: var(--color-cream);
}

.site-footer__slogan {
  margin: 0 0 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--color-accent);
}

.site-footer__statement {
  max-width: 42ch;
  margin: 0;
  font-size: 0.9rem;
  color: var(--color-silver);
}

.site-footer__title {
  margin: 0 0 1rem;
  font-family: var(--font-head);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-gold);
}

.footer-contact-list,
.footer-link-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer-contact-list__item {
  display: flex;
  flex-direction: column;
  margin-bottom: 0.6rem;
  font-size: 0.9rem;
  line-height: 1.5;
  word-break: break-word;
}

.footer-contact-list__label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-silver);
  opacity: 0.8;
}

.footer-link-list li {
  margin-bottom: 0.45rem;
}

.footer-link-list a {
  display: inline-block;
  color: var(--color-silver);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--transition), border-color var(--transition);
}

.footer-link-list a:hover {
  color: var(--color-accent);
  border-bottom-color: var(--color-accent);
}

.site-footer__bottom {
  border-top: 1px solid rgba(192, 192, 192, 0.15);
  padding-block: 1rem;
}

.site-footer__bottom-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.site-footer__copyright,
.site-footer__icp {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-silver);
}

@media (max-width: 640px) {
  .site-footer__bottom-inner {
    flex-direction: column;
    text-align: center;
  }
}

.back-to-top {
  position: fixed;
  right: 1.5rem;
  bottom: 1.5rem;
  z-index: 80;
  padding: 0.6rem 1rem;
  font-family: var(--font-head);
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--color-primary);
  background-color: var(--color-accent);
  border: 1px solid var(--color-accent);
  border-radius: var(--radius);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity var(--transition), transform var(--transition), visibility var(--transition), background-color var(--transition);
}

.back-to-top[data-visible] {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background-color: var(--color-primary);
  color: var(--color-accent);
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius);
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 0.95rem;
  line-height: 1;
  text-decoration: none;
  border: 2px solid transparent;
  cursor: pointer;
  transition: background-color var(--transition), color var(--transition), border-color var(--transition), transform var(--transition);
}

.button--accent {
  background-color: var(--color-accent);
  color: var(--color-primary);
  border-color: var(--color-accent);
}

.button--accent:hover {
  background-color: var(--color-primary);
  color: var(--color-accent);
  border-color: var(--color-accent);
}

.button--ghost {
  background-color: transparent;
  color: var(--color-accent);
  border-color: var(--color-silver);
}

.button--ghost:hover {
  border-color: var(--color-accent);
  background-color: rgba(252, 163, 17, 0.08);
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  list-style: none;
  margin: 0 0 2rem;
  padding: 0.75rem 1rem;
  background: var(--color-silver-light);
  border-left: 4px solid var(--color-gold);
  font-family: var(--font-mono);
  font-size: 0.8rem;
}

.breadcrumb li + li::before {
  content: "/";
  margin-right: 0.5rem;
  color: var(--color-silver);
}

.breadcrumb a {
  color: var(--color-secondary);
  text-decoration: none;
}

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

.prose {
  max-width: 72ch;
  margin-inline: auto;
  color: #233241;
  font-size: 1rem;
}

.prose h2 {
  margin-top: 2.5em;
  font-size: 1.75rem;
  color: var(--color-primary);
  border-bottom: 2px solid var(--color-gold);
  padding-bottom: 0.35em;
}

.prose h3 {
  margin-top: 2em;
  font-size: 1.3rem;
  color: var(--color-primary);
}

.prose p {
  margin: 1em 0;
}

.prose a {
  color: var(--color-info);
  text-decoration: underline;
}

.prose ul,
.prose ol {
  padding-left: 1.5rem;
  margin-block: 1em;
}

.prose li {
  margin-block: 0.3em;
}

.prose blockquote {
  margin: 1.5em 0;
  padding: 0.75rem 1.25rem;
  border-left: 4px solid var(--color-gold);
  background: var(--color-silver-light);
}

.hero {
  background: var(--color-primary);
  color: var(--color-cream);
  padding-block: clamp(3rem, 7vw, 5.5rem);
}

.hero__title {
  font-size: clamp(2.2rem, 6vw, 4.5rem);
  font-weight: 900;
  line-height: 1.05;
  color: var(--color-cream);
  margin: 0;
  text-transform: uppercase;
  clip-path: polygon(0 0, 100% 0, 100% 86%, 0 100%);
  padding-bottom: 0.18em;
}

.hero__lead {
  display: inline-block;
  margin-bottom: 0.75rem;
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.hero__subtitle {
  max-width: 60ch;
  color: var(--color-silver);
  font-size: 1.1rem;
  margin: 0;
}

.card {
  background: var(--color-cream);
  border-radius: var(--radius);
  border: 1px solid rgba(27, 38, 59, 0.15);
  padding: 1.5rem;
  color: var(--color-primary);
  box-shadow: 0 4px 18px rgba(13, 27, 42, 0.08);
  transition: border-color var(--transition), box-shadow var(--transition);
}

.card:hover {
  border-color: var(--color-accent);
  box-shadow: 0 10px 30px rgba(13, 27, 42, 0.16);
}

.card--stacked {
  position: relative;
  margin-top: 1.25rem;
}

.card--stacked::before {
  content: "";
  position: absolute;
  left: 12px;
  right: -12px;
  bottom: -12px;
  height: 100%;
  background: var(--color-secondary);
  border-radius: 4px;
  z-index: -1;
}

.section--dark .card--stacked::before {
  background: rgba(252, 163, 17, 0.35);
}

.tag {
  display: inline-block;
  padding: 0.3rem 0.7rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  border-radius: 2px;
  color: var(--color-secondary);
  background: var(--color-silver-light);
  border: 1px solid rgba(27, 38, 59, 0.2);
}

.tag--version {
  color: var(--color-primary);
  background: var(--color-accent);
  border-color: var(--color-accent);
}

.tag--danger {
  color: var(--color-white);
  background: var(--color-danger);
  border-color: var(--color-danger);
}

.alert {
  padding: 1rem 1.25rem;
  border-radius: var(--radius);
  background: var(--color-silver-light);
  border: 1px solid rgba(27, 38, 59, 0.2);
  font-size: 0.95rem;
  color: var(--color-primary);
}

.alert--danger {
  background: rgba(230, 57, 70, 0.12);
  border-color: var(--color-danger);
  color: #7a1f26;
}

.table-wrap {
  overflow-x: auto;
  border: 1px solid rgba(27, 38, 59, 0.18);
  border-radius: var(--radius);
  background: var(--color-cream);
}

.table-wrap table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.92rem;
  color: var(--color-primary);
}

.table-wrap th,
.table-wrap td {
  padding: 0.85rem 1rem;
  text-align: left;
  border-bottom: 1px solid rgba(27, 38, 59, 0.12);
  white-space: nowrap;
}

.table-wrap th {
  background: var(--color-secondary);
  color: var(--color-cream);
  font-family: var(--font-head);
  font-weight: 700;
  letter-spacing: 0.02em;
}

.table-wrap tr:last-child td {
  border-bottom: none;
}

.table-wrap td.diff-new {
  color: var(--color-gold);
  font-weight: 700;
}

.table-wrap td.diff-danger {
  color: var(--color-danger);
  font-weight: 700;
}

.step-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1.25rem;
}

.step-list__item {
  position: relative;
  display: grid;
  grid-template-columns: 3rem 1fr;
  gap: 1rem;
  padding: 1.25rem;
  background: var(--color-cream);
  border-left: 5px solid var(--color-gold);
  color: var(--color-primary);
  box-shadow: 0 4px 14px rgba(13, 27, 42, 0.08);
}

.step-list__item:not(:last-child)::after {
  content: "";
  position: absolute;
  left: 2.35rem;
  top: 100%;
  width: 2px;
  height: 1.25rem;
  background: var(--color-gold);
}

.step-list__number {
  font-family: var(--font-mono);
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--color-accent);
  line-height: 1;
}

.version-compare {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.5rem;
}

.version-card {
  position: relative;
  padding: 1.75rem;
  background: var(--color-cream);
  border: 2px solid rgba(27, 38, 59, 0.15);
  border-radius: var(--radius);
  color: var(--color-primary);
  box-shadow: 0 4px 18px rgba(13, 27, 42, 0.08);
}

.version-card--featured {
  border-color: var(--color-accent);
  box-shadow: 0 12px 30px rgba(252, 163, 17, 0.2);
}

.version-card__version {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1.1;
}

.version-card__name {
  color: var(--color-secondary);
  margin-top: 0.25rem;
  font-size: 1rem;
}

.version-card__status {
  margin-top: 0.75rem;
}

.query-panel {
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  border: 1px solid rgba(192, 192, 192, 0.25);
  border-radius: var(--radius);
  padding: 1.5rem;
  color: var(--color-cream);
}

.query-panel__title {
  color: var(--color-accent);
  font-size: 1.2rem;
  margin-bottom: 0.75rem;
}

.image-placeholder {
  position: relative;
  display: block;
  overflow: hidden;
  width: 100%;
  aspect-ratio: 4 / 3;
  background: linear-gradient(135deg, #1b263b, #0d1b2a 70%);
  border: 1px solid rgba(192, 192, 192, 0.3);
  border-radius: var(--radius);
}

.image-placeholder::before {
  content: attr(data-label);
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.15em;
  color: rgba(192, 192, 192, 0.55);
  text-transform: uppercase;
}

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

.image-placeholder--ratio-portrait {
  aspect-ratio: 3 / 4;
}

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

.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  color: var(--color-accent);
  text-decoration: none;
  font-family: var(--font-head);
  font-weight: 700;
  border-bottom: 2px solid transparent;
  transition: border-color var(--transition), gap var(--transition);
}

.link-arrow::after {
  content: "→";
  font-family: var(--font-mono);
  transition: transform var(--transition);
}

.link-arrow:hover {
  border-color: var(--color-accent);
  gap: 0.6rem;
}