:root {
  --bg-primary: #0A1F3C;
  --bg-secondary: #0F2A4A;
  --bg-surface: #12304F;
  --accent: #FF6B35;
  --accent-light: #FF8C5A;
  --text-primary: #FFFFFF;
  --text-secondary: #B0C4DE;
  --grid-line: #2A4A6B;
  --grad-start: #1E3A5F;
  --grad-end: #0A1F3C;
  --font-head: Georgia, "Times New Roman", serif;
  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "SF Mono", SFMono-Regular, Consolas, "Liberation Mono", Menlo, monospace;
  --container-max: 1200px;
  --header-h: 80px;
  --radius: 0;
  --ease: 0.25s ease;
}

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

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

body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--ease);
}

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

ul,
ol {
  list-style: none;
}

button {
  font-family: inherit;
  font-size: inherit;
  line-height: inherit;
  border: none;
  background: none;
  cursor: pointer;
  color: inherit;
  border-radius: var(--radius);
}

address {
  font-style: normal;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-head);
  line-height: 1.25;
  font-weight: 700;
  color: var(--text-primary);
}

::selection {
  background: var(--accent);
  color: #fff;
}

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

#main-content {
  min-height: 60vh;
  scroll-margin-top: calc(var(--header-h) + 16px);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 20px;
  font-size: 14px;
  font-weight: 600;
  line-height: 1.4;
  font-family: var(--font-body);
  border-radius: var(--radius);
  border: 1px solid transparent;
  transition: background var(--ease), color var(--ease), border-color var(--ease);
}

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--accent-light);
  border-color: var(--accent-light);
  color: #fff;
}

.btn-ghost {
  background: transparent;
  border-color: var(--grid-line);
  color: var(--text-primary);
}

.btn-ghost:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: rgba(255, 107, 53, 0.06);
}

.skip-link {
  position: fixed;
  top: -56px;
  left: 16px;
  z-index: 200;
  background: var(--accent);
  color: #fff;
  padding: 10px 18px;
  font-size: 14px;
  font-weight: 600;
  border-radius: var(--radius);
  transition: top var(--ease);
}

.skip-link:focus {
  top: 8px;
}

.skip-link:focus-visible {
  outline: 2px solid #fff;
  outline-offset: 2px;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 32px 32px;
  background-position: 0 0;
  background-color: var(--bg-surface);
  border-bottom: 1px solid var(--grid-line);
  box-shadow: 0 6px 24px rgba(0, 0, 0, 0.25);
}

.probe-track {
  height: 3px;
  background: var(--grid-line);
  position: relative;
  overflow: hidden;
}

.probe-bar {
  display: block;
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--accent), var(--accent-light));
  transition: width 0.12s linear;
}

.header-frame {
  min-height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand-lockup {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--text-primary);
  flex: none;
}

.brand-lockup:hover {
  color: var(--text-primary);
}

.brand-mark {
  position: relative;
  width: 38px;
  height: 38px;
  flex: none;
  border: 2px solid var(--accent);
  background:
    linear-gradient(to right, transparent calc(50% - 1px), var(--grid-line) calc(50% - 1px), var(--grid-line) calc(50% + 1px), transparent calc(50% + 1px)),
    linear-gradient(to bottom, transparent calc(50% - 1px), var(--grid-line) calc(50% - 1px), var(--grid-line) calc(50% + 1px), transparent calc(50% + 1px));
}

.brand-mark-core {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 7px;
  height: 7px;
  background: var(--accent);
  transform: translate(-50%, -50%);
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
  white-space: nowrap;
}

.brand-name {
  font-family: var(--font-head);
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--text-primary);
}

.brand-slogan {
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.14em;
  color: var(--text-secondary);
  margin-top: 3px;
}

.frame-nav {
  display: flex;
  align-items: stretch;
}

.frame-nav::before,
.frame-nav::after {
  content: "";
  display: block;
  width: 14px;
  height: 1px;
  background: var(--accent);
  flex: none;
  align-self: center;
}

.frame-nav::before {
  margin-right: 10px;
}

.frame-nav::after {
  margin-left: 10px;
}

.nav-list {
  display: flex;
  align-items: stretch;
}

.nav-item {
  display: flex;
  align-items: stretch;
}

.nav-item + .nav-item {
  border-left: 1px solid var(--grid-line);
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 5px;
  padding: 9px 12px;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-primary);
  position: relative;
  white-space: nowrap;
  transition: color var(--ease), background var(--ease);
}

.nav-link:hover {
  color: var(--accent-light);
  background: rgba(255, 107, 53, 0.06);
}

.nav-index {
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--accent);
  letter-spacing: 0.04em;
}

.nav-label {
  white-space: nowrap;
}

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

.nav-link[aria-current="page"]::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 12px;
  right: 12px;
  height: 2px;
  background: var(--accent);
}

.btn-cta {
  flex: none;
  border: none;
  background: var(--accent);
  color: #fff;
  clip-path: polygon(10px 0, 100% 0, calc(100% - 10px) 100%, 0 100%);
  padding: 10px 22px;
  white-space: nowrap;
}

.btn-cta:hover {
  background: var(--accent-light);
  color: #fff;
}

.nav-toggle {
  display: none;
  position: relative;
  width: 44px;
  height: 44px;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--grid-line);
  background: rgba(255, 107, 53, 0.06);
  flex: none;
}

.nav-toggle-box {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  width: 18px;
  height: 18px;
}

.nav-toggle-line {
  display: block;
  height: 2px;
  background: var(--accent);
  transition: transform var(--ease), opacity var(--ease);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

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

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

.site-footer {
  position: relative;
  margin-top: 80px;
  background-color: var(--grad-start);
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px),
    linear-gradient(180deg, var(--grad-start), var(--grad-end));
  background-size: 32px 32px, 32px 32px, 100% 100%;
  border-top: 3px solid var(--accent);
  color: var(--text-primary);
}

.site-footer::before {
  content: "";
  position: absolute;
  top: 8px;
  right: 48px;
  width: 140px;
  height: 2px;
  background: var(--accent);
  transform: skewX(-24deg);
  opacity: 0.3;
  pointer-events: none;
}

.site-footer::after {
  content: "";
  position: absolute;
  top: 13px;
  right: 64px;
  width: 100px;
  height: 2px;
  background: var(--accent-light);
  transform: skewX(-24deg);
  opacity: 0.2;
  pointer-events: none;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: 40px;
  padding-block: 64px 48px;
}

.footer-col {
  min-width: 0;
}

.footer-statement {
  margin-top: 16px;
  max-width: 280px;
  font-size: 14px;
  line-height: 1.8;
  color: var(--text-secondary);
}

.footer-heading {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 18px;
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--text-primary);
}

.heading-index {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  background: var(--accent);
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 700;
  color: #fff;
  flex: none;
}

.footer-nav-list li + li {
  margin-top: 10px;
}

.footer-nav-list a {
  font-size: 14px;
  color: var(--text-secondary);
  transition: color var(--ease), padding-left var(--ease);
}

.footer-nav-list a:hover {
  color: var(--accent-light);
  padding-left: 4px;
}

.footer-contact {
  display: flex;
  gap: 10px;
  margin-bottom: 12px;
}

.coord-label {
  flex: none;
  width: 56px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--text-secondary);
}

.contact-value {
  font-size: 14px;
  color: var(--text-primary);
  overflow-wrap: anywhere;
  line-height: 1.5;
}

.footer-legal {
  border-top: 1px solid var(--grid-line);
  background: rgba(0, 0, 0, 0.18);
}

.footer-legal-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 24px;
  padding-block: 16px;
}

.legal-copy,
.legal-icp,
.legal-domain {
  font-size: 12px;
  color: var(--text-secondary);
  font-family: var(--font-body);
}

.to-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 90;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-surface);
  border: 1px solid var(--grid-line);
  color: var(--accent);
  font-size: 20px;
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transform: translateY(12px);
  transition: opacity 0.3s ease, transform 0.3s ease, border-color var(--ease), background var(--ease);
}

.to-top.is-visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

.to-top:hover {
  border-color: var(--accent);
  background: rgba(255, 107, 53, 0.12);
  color: var(--accent-light);
}

.to-top-icon {
  line-height: 1;
  transform: translateY(-1px);
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 28px;
  font-size: 13px;
  color: var(--text-secondary);
}

.breadcrumb a {
  color: var(--text-secondary);
  transition: color var(--ease);
}

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

.breadcrumb-sep {
  color: var(--grid-line);
}

.page-head {
  position: relative;
  padding: 48px 0 28px;
  margin-bottom: 36px;
  border-bottom: 1px solid var(--grid-line);
}

.page-head::after {
  content: "GRID/INDEX";
  position: absolute;
  right: 4px;
  bottom: 14px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.24em;
  color: var(--grid-line);
}

.page-title {
  font-size: clamp(30px, 5vw, 48px);
  line-height: 1.15;
  color: var(--text-primary);
  letter-spacing: 0.01em;
}

.page-meta {
  margin-top: 12px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px 24px;
  font-size: 14px;
  color: var(--text-secondary);
}

.content-body {
  max-width: 760px;
  font-size: 16px;
  line-height: 1.85;
  color: var(--text-primary);
}

.content-body p + p {
  margin-top: 16px;
}

.section {
  margin-top: 56px;
}

.section-head {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 24px;
}

.section-title {
  font-size: 32px;
  line-height: 1.3;
  color: var(--text-primary);
}

.section-title::before {
  content: "";
  display: inline-block;
  width: 8px;
  height: 24px;
  background: var(--accent);
  margin-right: 12px;
  vertical-align: middle;
}

.grid-split {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 48px;
  align-items: start;
}

.card {
  background: var(--bg-secondary);
  border: 1px solid var(--grid-line);
  padding: 24px;
  border-radius: var(--radius);
}

.tag {
  display: inline-flex;
  align-items: center;
  padding: 2px 10px;
  font-size: 12px;
  font-weight: 600;
  line-height: 1.6;
  color: var(--accent);
  border: 1px solid var(--accent);
  border-radius: var(--radius);
}

.data-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  color: var(--text-secondary);
}

.data-chip::before {
  content: "";
  width: 6px;
  height: 6px;
  background: var(--accent);
  flex: none;
}

.image-frame {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  border: 1px solid var(--grid-line);
  background-color: var(--bg-secondary);
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 20px 20px;
}

.image-frame::after {
  content: "IMG";
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--grid-line);
}

.image-frame img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.image-frame--tall {
  aspect-ratio: 4 / 5;
}

.image-frame--wide {
  aspect-ratio: 21 / 9;
}

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

@media (max-width: 1024px) {
  .nav-toggle {
    display: flex;
  }

  .btn-cta {
    display: none;
  }

  .frame-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    display: none;
    margin: 0;
    background: var(--bg-surface);
    border-top: 1px solid var(--grid-line);
    border-bottom: 3px solid var(--accent);
    box-shadow: 0 16px 32px rgba(0, 0, 0, 0.3);
  }

  .frame-nav[data-open="true"] {
    display: block;
  }

  .frame-nav::before,
  .frame-nav::after {
    display: none;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    padding: 10px 16px;
  }

  .nav-item + .nav-item {
    border-left: none;
    border-top: 1px solid var(--grid-line);
  }

  .nav-link {
    padding: 12px 8px;
    border-left: 3px solid transparent;
  }

  .nav-link[aria-current="page"] {
    background: rgba(255, 107, 53, 0.08);
    border-left: 3px solid var(--accent);
    color: var(--accent);
  }

  .nav-link[aria-current="page"]::after {
    display: none;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }

  .grid-split {
    grid-template-columns: 1fr;
    gap: 32px;
  }
}

@media (max-width: 640px) {
  .container {
    padding-inline: 16px;
  }

  .header-frame {
    gap: 8px;
  }

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

  .brand-name {
    font-size: 17px;
  }

  .brand-slogan {
    font-size: 9px;
  }

  .page-head::after {
    display: none;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
    padding-block: 48px 32px;
  }

  .site-footer::before,
  .site-footer::after {
    display: none;
  }

  .footer-legal-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 6px;
  }

  .to-top {
    right: 16px;
    bottom: 16px;
    width: 44px;
    height: 44px;
  }
}

@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;
  }
}