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

:root {
  --color-primary-bg: #0A192F;
  --color-accent: #FF6B35;
  --color-gold: #FFD700;
  --color-ink-blue: #112340;
  --color-paper: #F5F1E8;
  --color-muted-blue: #223A5E;
  --color-orange-deep: #E55D29;
  --color-cream-border: #E8DCC8;
  --color-text-light: #F5F1E8;
  --color-text-dark: #0A192F;
  --color-text-muted: rgba(245, 241, 232, 0.72);

  --font-headline: Impact, "Arial Black", "Helvetica Neue", sans-serif;
  --font-body: Georgia, "Songti SC", SimSun, serif;

  --border-width: 4px;
  --border-width-sm: 2px;
  --shadow-hard: 8px 8px 0 rgba(10, 25, 47, 0.35);
  --shadow-hard-accent: 8px 8px 0 rgba(255, 107, 53, 0.35);

  --container-max: 1240px;
  --gutter: 24px;
  --transition-fast: 120ms;
  --transition-mid: 240ms;

  --font-size-display: 64px;
  --font-size-h1: 44px;
  --font-size-h2: 28px;
  --font-size-h3: 20px;
  --font-size-body: 16px;
}

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

body {
  font-family: var(--font-body);
  font-size: var(--font-size-body);
  line-height: 1.75;
  letter-spacing: 0.01em;
  color: var(--color-text-light);
  background-color: var(--color-primary-bg);
  background-image:
    radial-gradient(circle, rgba(255, 255, 255, 0.03) 0.5px, transparent 0.5px),
    radial-gradient(circle, rgba(255, 255, 255, 0.02) 0.5px, transparent 0.5px);
  background-size: 4px 4px, 8px 8px;
  background-position: 0 0, 2px 2px;
  min-height: 100vh;
}

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

:where(ul, ol) {
  list-style: none;
}

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

button {
  font: inherit;
  color: inherit;
  cursor: pointer;
  background: none;
  border: none;
}

h1, h2, h3, h4 {
  font-family: var(--font-headline);
  font-style: italic;
  text-transform: uppercase;
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--color-text-light);
}

h1 { font-size: var(--font-size-h1); }
h2 { font-size: var(--font-size-h2); }
h3 { font-size: var(--font-size-h3); }

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

::selection {
  background: var(--color-accent);
  color: var(--color-primary-bg);
}

[hidden] {
  display: none !important;
}

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

.skip-link {
  position: absolute;
  top: -100%;
  left: 24px;
  z-index: 9999;
  padding: 12px 20px;
  background: var(--color-accent);
  color: var(--color-primary-bg);
  font-family: var(--font-headline);
  font-size: 15px;
  font-style: italic;
  text-transform: uppercase;
  transition: top var(--transition-fast);
}
.skip-link:focus {
  top: 0;
}

.container {
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.main-content {
  min-height: 50vh;
  position: relative;
}

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  z-index: 1001;
  background: rgba(255, 255, 255, 0.06);
  transform-origin: 0 0;
  transform: scaleX(0);
  pointer-events: none;
}

.site-header {
  position: relative;
  z-index: 100;
  background: var(--color-primary-bg);
  color: var(--color-text-light);
  border-bottom: var(--border-width) solid var(--color-accent);
}

.header-topbar {
  background: var(--color-ink-blue);
  border-bottom: 1px solid var(--color-muted-blue);
}

.header-topbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding-top: 8px;
  padding-bottom: 8px;
}

.version-switch {
  display: flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
}

.version-switch-label {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  white-space: nowrap;
}

.version-switch-track {
  display: flex;
  align-items: center;
  background: var(--color-primary-bg);
  border: 2px solid var(--color-muted-blue);
  border-radius: 100px;
  padding: 2px;
}

.version-switch-btn {
  padding: 4px 14px;
  font-family: var(--font-headline);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  border-radius: 100px;
  color: var(--color-text-muted);
  transition: background var(--transition-fast), color var(--transition-fast);
}

.version-switch-btn:hover {
  color: var(--color-text-light);
}

.version-switch-btn.is-active {
  background: var(--color-accent);
  color: var(--color-primary-bg);
}

.version-switch-btn[data-version-btn="old"].is-active {
  background: var(--color-gold);
  color: var(--color-primary-bg);
}

.icp-query-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 10px;
  font-size: 13px;
  color: var(--color-text-light);
  border: 2px solid transparent;
  letter-spacing: 0.03em;
  transition: border-color var(--transition-fast), color var(--transition-fast);
}

.icp-query-btn:hover {
  border-color: var(--color-gold);
  color: var(--color-gold);
}

.icp-query-icon {
  display: inline-block;
  width: 14px;
  height: 14px;
  border: 2px solid currentColor;
  border-radius: 50%;
  position: relative;
  flex-shrink: 0;
}

.icp-query-icon::after {
  content: "";
  position: absolute;
  width: 8px;
  height: 2px;
  background: currentColor;
  bottom: -4px;
  right: -4px;
  transform: rotate(45deg);
}

.header-masthead {
  padding: 28px 0 20px;
  text-align: center;
}

.header-masthead .container {
  position: relative;
}

.header-masthead .container::before,
.header-masthead .container::after {
  content: "";
  position: absolute;
  top: 50%;
  width: 18%;
  height: 2px;
  pointer-events: none;
}

.header-masthead .container::before {
  left: 0;
  background: linear-gradient(90deg, transparent, var(--color-accent));
}

.header-masthead .container::after {
  right: 0;
  background: linear-gradient(270deg, transparent, var(--color-accent));
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  vertical-align: middle;
}

.brand-symbol {
  display: block;
  width: 48px;
  height: 48px;
  flex-shrink: 0;
  background:
    radial-gradient(circle at 32% 32%, var(--color-accent) 0%, var(--color-accent) 26%, transparent 28%),
    var(--color-ink-blue);
  border: 3px solid var(--color-accent);
  border-radius: 8px;
  position: relative;
  overflow: hidden;
}

.brand-symbol::after {
  content: "";
  position: absolute;
  top: 50%;
  left: -12%;
  width: 124%;
  height: 4px;
  background: var(--color-gold);
  transform: rotate(-42deg);
  opacity: 0.9;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
  text-align: left;
}

.brand-name {
  font-family: var(--font-headline);
  font-style: italic;
  font-size: 32px;
  letter-spacing: -0.02em;
  text-transform: uppercase;
  color: var(--color-text-light);
}

.brand-subline {
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-top: 4px;
}

.site-nav {
  background: var(--color-primary-bg);
  border-top: 2px solid var(--color-muted-blue);
  border-bottom: 2px solid var(--color-muted-blue);
  position: relative;
}

.nav-container {
  display: flex;
  justify-content: center;
  align-items: center;
}

.nav-list {
  display: flex;
  gap: 0;
}

.nav-link {
  display: block;
  padding: 13px 18px;
  font-family: var(--font-headline);
  font-size: 15px;
  text-transform: uppercase;
  letter-spacing: 0.02em;
  color: var(--color-text-light);
  position: relative;
  transition: background var(--transition-fast), color var(--transition-fast);
}

.nav-link:hover {
  background: var(--color-ink-blue);
  color: var(--color-gold);
}

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

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 0;
  margin: 6px 0;
  border: 2px solid transparent;
  transition: border-color var(--transition-fast);
}

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

.nav-toggle-bar {
  display: block;
  width: 24px;
  height: 3px;
  background: var(--color-accent);
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.site-footer {
  position: relative;
  background: var(--color-ink-blue);
  color: var(--color-text-light);
  border-top: var(--border-width) solid var(--color-accent);
  margin-top: 64px;
}

.footer-diagonal {
  height: 80px;
  background: linear-gradient(
    to right bottom,
    var(--color-primary-bg) 0%,
    var(--color-primary-bg) 32%,
    var(--color-accent) 32%,
    var(--color-accent) 37%,
    var(--color-ink-blue) 37%,
    var(--color-ink-blue) 100%
  );
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 2fr;
  gap: 40px;
  padding-top: 40px;
  padding-bottom: 40px;
}

.footer-brand-col .brand {
  margin-bottom: 16px;
}

.footer-brand .brand-name {
  font-size: 22px;
}

.footer-brand .brand-symbol {
  width: 36px;
  height: 36px;
  border-width: 2px;
}

.footer-desc {
  font-size: 15px;
  line-height: 1.7;
  color: var(--color-text-muted);
  max-width: 32em;
}

.footer-heading {
  font-size: 16px;
  color: var(--color-gold);
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--color-muted-blue);
}

.footer-links {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4px 16px;
}

.footer-links a {
  display: inline-block;
  padding: 4px 0;
  font-size: 14px;
  color: var(--color-text-light);
  transition: color var(--transition-fast), padding-left var(--transition-fast);
}

.footer-links a:hover {
  color: var(--color-gold);
  padding-left: 6px;
}

.footer-contact-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.contact-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 14px;
  line-height: 1.6;
  color: var(--color-text-light);
}

.contact-icon {
  flex-shrink: 0;
  display: inline-block;
  width: 20px;
  text-align: center;
  font-weight: bold;
  color: var(--color-accent);
  line-height: 1.4;
}

.footer-bottom {
  background: var(--color-primary-bg);
  border-top: 2px solid var(--color-muted-blue);
  padding: 16px 0;
}

.footer-bottom-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.footer-copyright {
  font-size: 13px;
  color: var(--color-text-muted);
}

.footer-icp {
  font-size: 13px;
  border: 1px solid var(--color-muted-blue);
  border-radius: 4px;
  padding: 6px 12px;
}

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

.modal {
  position: fixed;
  inset: 0;
  z-index: 2000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
}

.modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(10, 25, 47, 0.88);
  backdrop-filter: blur(3px);
}

.modal-content {
  position: relative;
  z-index: 1;
  max-width: 520px;
  width: 100%;
  background:
    radial-gradient(circle, rgba(10, 25, 47, 0.05) 0.5px, transparent 0.5px),
    var(--color-paper);
  background-size: 4px 4px, auto;
  color: var(--color-text-dark);
  border: var(--border-width) solid var(--color-accent);
  box-shadow: var(--shadow-hard-accent);
  padding: 32px;
  animation: modal-in var(--transition-fast) ease-out;
}

@keyframes modal-in {
  from {
    opacity: 0;
    transform: translateY(24px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.modal-close {
  position: absolute;
  top: 10px;
  right: 10px;
  width: 36px;
  height: 36px;
  font-size: 22px;
  line-height: 1;
  color: var(--color-text-dark);
  border: 2px solid transparent;
  transition: border-color var(--transition-fast), color var(--transition-fast);
}

.modal-close:hover {
  border-color: var(--color-orange-deep);
  color: var(--color-orange-deep);
}

.modal-title {
  font-size: 26px;
  color: var(--color-text-dark);
  margin-bottom: 20px;
  position: relative;
  padding-left: 14px;
}

.modal-title::before {
  content: "";
  position: absolute;
  left: 0;
  top: 6px;
  bottom: 6px;
  width: 6px;
  background: var(--color-orange-deep);
}

.icp-facts {
  margin-bottom: 24px;
}

.icp-fact {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: 8px;
  padding: 10px 0;
  border-bottom: 1px solid var(--color-cream-border);
}

.icp-fact dt {
  font-family: var(--font-headline);
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  color: var(--color-orange-deep);
}

.icp-fact dd {
  margin: 0;
  font-size: 14px;
  color: var(--color-text-dark);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: var(--font-headline);
  font-size: 15px;
  font-style: italic;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  line-height: 1.4;
  padding: 12px 24px;
  position: relative;
  transition: background var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast);
}

.btn-solid {
  background: var(--color-accent);
  color: var(--color-primary-bg);
  border: 2px solid var(--color-accent);
  box-shadow: 4px 4px 0 rgba(10, 25, 47, 0.35);
}

.btn-solid:hover {
  background: var(--color-orange-deep);
  border-color: var(--color-orange-deep);
  color: var(--color-text-light);
}

.btn-outline {
  background: transparent;
  color: var(--color-accent);
  border: 2px solid var(--color-accent);
}

.btn-outline:hover {
  background: var(--color-accent);
  color: var(--color-primary-bg);
}

.card {
  background-image: radial-gradient(circle, rgba(255, 255, 255, 0.04) 0.5px, transparent 0.5px);
  background-size: 4px 4px;
  background-color: var(--color-ink-blue);
  border: var(--border-width) solid var(--color-muted-blue);
  box-shadow: var(--shadow-hard);
  padding: 24px;
  transition: border-color var(--transition-fast);
}

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

.card.is-paper {
  background-image: radial-gradient(circle, rgba(10, 25, 47, 0.05) 0.5px, transparent 0.5px);
  background-size: 4px 4px;
  background-color: var(--color-paper);
  color: var(--color-text-dark);
  border-color: var(--color-cream-border);
}

.card.is-paper h1,
.card.is-paper h2,
.card.is-paper h3 {
  color: var(--color-text-dark);
}

.section {
  padding: 56px 0;
}

.section.is-paper {
  background: var(--color-paper);
  color: var(--color-text-dark);
}

.section.is-paper .section-title {
  color: var(--color-text-dark);
}

.section-title {
  font-size: var(--font-size-h2);
  color: var(--color-text-light);
  position: relative;
  padding-left: 16px;
  margin-bottom: 24px;
}

.section-title::before {
  content: "";
  position: absolute;
  left: 0;
  top: 4px;
  bottom: 4px;
  width: 6px;
  background: var(--color-accent);
}

.eyebrow {
  display: block;
  font-family: var(--font-headline);
  font-size: 14px;
  font-style: italic;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-accent);
  margin-bottom: 8px;
}

.page-header {
  padding: 40px 0 32px;
  border-bottom: var(--border-width) solid var(--color-accent);
  margin-bottom: 40px;
}

.page-title {
  font-size: var(--font-size-h1);
  color: var(--color-text-light);
  line-height: 1.15;
}

.page-header.is-paper .page-title {
  color: var(--color-text-dark);
}

.grid {
  display: grid;
  gap: var(--gutter);
}

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

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

.grid-cols-5-7 {
  grid-template-columns: 5fr 7fr;
}

.grid-cols-7-5 {
  grid-template-columns: 7fr 5fr;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-headline);
  font-size: 12px;
  font-style: italic;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 4px 12px;
  background: var(--color-accent);
  color: var(--color-primary-bg);
  border: 2px solid var(--color-primary-bg);
  box-shadow: 3px 3px 0 rgba(10, 25, 47, 0.3);
}

.badge.is-gold {
  background: var(--color-gold);
}

.tag {
  display: inline-block;
  font-family: var(--font-body);
  font-size: 14px;
  padding: 6px 14px;
  background: transparent;
  border: 2px solid var(--color-muted-blue);
  color: var(--color-text-light);
  cursor: pointer;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast), color var(--transition-fast);
}

.tag:hover {
  border-color: var(--color-accent);
  color: var(--color-gold);
}

.tag.is-active {
  border-color: var(--color-orange-deep);
  color: var(--color-gold);
  box-shadow: inset 0 -3px 0 var(--color-accent);
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  font-size: 14px;
  color: var(--color-text-muted);
  margin-bottom: 16px;
}

.breadcrumb li + li::before {
  content: "／";
  margin-right: 4px;
  color: var(--color-muted-blue);
}

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

.diagonal-divider {
  height: 72px;
  position: relative;
  overflow: hidden;
  background: var(--color-primary-bg);
  border-bottom: 2px solid var(--color-muted-blue);
}

.diagonal-divider::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 140%;
  height: 100%;
  background: linear-gradient(
    to right bottom,
    transparent 43%,
    var(--color-accent) 43%,
    var(--color-accent) 48%,
    transparent 48%
  );
}

.flip-card {
  position: relative;
  perspective: 1200px;
  cursor: pointer;
}

.flip-card-inner {
  position: relative;
  transform-style: preserve-3d;
  transition: transform var(--transition-mid) ease;
}

.flip-card.is-flipped .flip-card-inner {
  transform: rotateY(180deg);
}

.flip-card-face {
  backface-visibility: hidden;
}

.flip-card-back {
  position: absolute;
  inset: 0;
  transform: rotateY(180deg);
}

[data-accordion-panel] {
  display: none;
}

[data-accordion-panel].is-open {
  display: block;
}

.is-hidden {
  display: none !important;
}

body.is-retro::before {
  content: "";
  position: fixed;
  inset: 16px;
  z-index: 1500;
  pointer-events: none;
  border: 6px double var(--color-accent);
}

body.is-retro::after {
  content: "旧版界面";
  position: fixed;
  top: 30px;
  right: 30px;
  z-index: 1501;
  padding: 6px 16px;
  background: var(--color-primary-bg);
  color: var(--color-gold);
  border: 2px solid var(--color-gold);
  font-family: var(--font-headline);
  font-size: 13px;
  font-style: italic;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  transform: rotate(3deg);
  pointer-events: none;
}

@media (max-width: 960px) {
  .nav-container {
    justify-content: flex-start;
  }

  .nav-list {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    z-index: 50;
    flex-direction: column;
    background: var(--color-ink-blue);
    border-bottom: var(--border-width) solid var(--color-accent);
    box-shadow: 8px 8px 0 rgba(10, 25, 47, 0.5);
  }

  .site-nav[data-open="true"] .nav-list {
    display: flex;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-link {
    padding: 15px 24px;
    border-top: 1px solid var(--color-muted-blue);
  }

  .nav-item:first-child .nav-link {
    border-top: none;
  }

  .site-nav[data-open="true"] .nav-toggle-bar:nth-child(2) {
    transform: translateY(8px) rotate(45deg);
  }

  .site-nav[data-open="true"] .nav-toggle-bar:nth-child(3) {
    opacity: 0;
  }

  .site-nav[data-open="true"] .nav-toggle-bar:nth-child(4) {
    transform: translateY(-8px) rotate(-45deg);
  }

  .grid-cols-2,
  .grid-cols-3,
  .grid-cols-5-7,
  .grid-cols-7-5 {
    grid-template-columns: 1fr;
  }

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

  .footer-brand-col {
    grid-column: 1 / -1;
  }

  .footer-links a {
    font-size: 14px;
  }
}

@media (max-width: 640px) {
  .header-topbar-inner {
    flex-wrap: wrap;
  }

  .version-switch-label {
    display: none;
  }

  .version-switch-btn {
    padding: 3px 10px;
    font-size: 11px;
  }

  .icp-query-btn span:last-child {
    font-size: 12px;
  }

  .header-masthead {
    padding: 20px 0 16px;
  }

  .header-masthead .container::before,
  .header-masthead .container::after {
    display: none;
  }

  .brand-name {
    font-size: 24px;
  }

  .brand-symbol {
    width: 38px;
    height: 38px;
    border-width: 2px;
  }

  .brand-subline {
    font-size: 10px;
    letter-spacing: 0.16em;
  }

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

  .footer-brand-col {
    grid-column: auto;
  }

  .footer-links {
    grid-template-columns: 1fr 1fr;
  }

  .footer-bottom-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .modal-content {
    padding: 24px 20px;
  }

  .icp-fact {
    grid-template-columns: 1fr;
    gap: 2px;
  }

  .section {
    padding: 36px 0;
  }

  .page-header {
    padding: 28px 0 24px;
  }

  .scroll-progress {
    height: 3px;
  }

  body.is-retro::before {
    inset: 8px;
    border-width: 3px;
  }

  body.is-retro::after {
    top: 16px;
    right: 16px;
    font-size: 11px;
    padding: 4px 10px;
  }
}

@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;
  }

  .modal-content {
    animation: none;
  }

  .flip-card-inner {
    transform: none !important;
  }

  .flip-card {
    perspective: none;
  }

  .flip-card-back {
    position: absolute;
    inset: 0;
    transform: none;
    opacity: 0;
    transition: opacity var(--transition-fast) linear;
  }

  .flip-card.is-flipped .flip-card-front {
    opacity: 0;
  }

  .flip-card.is-flipped .flip-card-back {
    opacity: 1;
  }
}