:root {
  --bg-primary: #0D0D0D;
  --bg-secondary: #1A1A1A;
  --bg-tertiary: #2A2A2A;
  --accent-green: #39FF14;
  --accent-blue: #00BFFF;
  --neutral-gray: #8C8C8C;
  --text-primary: #FFFFFF;
  --text-secondary: #B3B3B3;
  --glass-light: rgba(255,255,255,0.1);
  --glass-medium: rgba(255,255,255,0.2);
  --font-heading: 'Inter', 'Noto Sans SC', sans-serif;
  --font-body: 'Noto Sans SC', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
  --nav-width: 240px;
  --nav-width-mobile: 280px;
  --transition-speed: 0.3s;
  --z-nav: 1000;
  --z-overlay: 900;
  --z-progress: 1100;
  --z-skip: 1200;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

@media (max-width: 1023.98px) {
  html { font-size: 15px; }
}

@media (max-width: 639.98px) {
  html { font-size: 14px; }
}

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-body);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

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

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

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
  html { scroll-behavior: auto; }
}

/* Skip Link */
.skip-link {
  position: fixed;
  top: -100%;
  left: 1rem;
  z-index: var(--z-skip);
  padding: 0.5rem 1rem;
  background-color: var(--accent-green);
  color: var(--bg-primary);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 700;
  text-decoration: none;
  border-radius: 0 0 4px 4px;
  transition: top 0.2s ease;
}
.skip-link:focus {
  top: 0;
}

/* Scroll Progress */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  z-index: var(--z-progress);
  background-color: transparent;
  pointer-events: none;
}
.scroll-progress-bar {
  display: block;
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--accent-green), var(--accent-blue));
  transition: width 0.1s linear;
}

/* Header & Navigation */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--nav-width);
  height: 100vh;
  z-index: var(--z-nav);
  display: flex;
  flex-direction: column;
  background: linear-gradient(135deg, rgba(13,13,13,0.92), rgba(26,26,26,0.88));
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-right: 1px solid var(--glass-light);
  overflow-y: auto;
}

.header-mobile-bar {
  display: none;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1rem;
  background-color: var(--bg-primary);
  border-bottom: 1px solid var(--glass-light);
}

.header-mobile-logo {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.25rem;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: 0.02em;
}

.header-mobile-logo:hover {
  color: var(--accent-green);
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.25rem;
  flex-direction: column;
  gap: 4px;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
}

.nav-toggle-line {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--text-primary);
  border-radius: 1px;
  transition: transform var(--transition-speed) ease, opacity var(--transition-speed) 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-nav {
  display: flex;
  flex-direction: column;
  height: 100%;
  padding: 2rem 0;
}

.nav-brand {
  padding: 0 1.5rem 2rem;
  border-bottom: 1px solid var(--glass-light);
  margin-bottom: 2rem;
}

.nav-logo {
  display: block;
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.5rem;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: 0.02em;
  transition: color var(--transition-speed) ease;
}

.nav-logo:hover {
  color: var(--accent-green);
}

.nav-subtitle {
  display: block;
  margin-top: 0.25rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--neutral-gray);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.nav-list {
  list-style: none;
  flex: 1;
  padding: 0 1rem;
}

.nav-list li {
  margin-bottom: 0.25rem;
}

.nav-list a {
  display: flex;
  align-items: center;
  padding: 0.625rem 1rem;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: 6px;
  transition: background-color var(--transition-speed) ease, color var(--transition-speed) ease, box-shadow var(--transition-speed) ease;
  position: relative;
  letter-spacing: 0.02em;
}

.nav-list a:hover {
  color: var(--accent-blue);
  background-color: var(--glass-light);
  box-shadow: 0 0 12px rgba(0,191,255,0.15);
}

.nav-list a[aria-current="page"] {
  color: var(--accent-green);
  background-color: rgba(57,255,20,0.08);
  box-shadow: inset 3px 0 0 var(--accent-green);
  font-weight: 700;
}

.nav-list a[aria-current="page"]::before {
  content: '▸';
  margin-right: 0.5rem;
  color: var(--accent-green);
  font-size: 0.75rem;
}

.nav-footer {
  padding: 1.5rem 1.5rem 0;
  border-top: 1px solid var(--glass-light);
  margin-top: 2rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.nav-slogan {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--neutral-gray);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.nav-badge {
  display: inline-block;
  align-self: flex-start;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--bg-primary);
  background-color: var(--accent-green);
  padding: 0.15rem 0.5rem;
  border-radius: 3px;
  font-weight: 700;
  letter-spacing: 0.05em;
}

.nav-overlay {
  display: none;
}

/* Main Content */
.site-main {
  margin-left: var(--nav-width);
  flex: 1;
  padding: 2rem 2.5rem;
  min-height: 100vh;
  width: 100%;
  max-width: 1280px;
}

#main-content {
  scroll-margin-top: 2rem;
}

/* Breadcrumb */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.375rem;
  flex-wrap: wrap;
  margin-bottom: 2rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--neutral-gray);
  letter-spacing: 0.03em;
}

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

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

.breadcrumb-sep {
  color: var(--neutral-gray);
  font-size: 0.8rem;
  user-select: none;
}

.breadcrumb-current {
  color: var(--accent-green);
  font-weight: 500;
}

/* Footer */
.site-footer {
  margin-left: var(--nav-width);
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--glass-light);
  padding: 3rem 2.5rem 1.5rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1.5fr;
  gap: 2.5rem;
  max-width: 1200px;
  margin: 0 auto;
}

.footer-logo {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.25rem;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: 0.02em;
  transition: color var(--transition-speed) ease;
}

.footer-logo:hover {
  color: var(--accent-green);
}

.footer-desc {
  margin-top: 0.75rem;
  font-size: 0.875rem;
  color: var(--neutral-gray);
  line-height: 1.6;
  max-width: 24rem;
}

.footer-heading {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--glass-light);
}

.footer-link-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-link-list a {
  font-size: 0.875rem;
  color: var(--text-secondary);
  text-decoration: none;
  transition: color var(--transition-speed) ease;
}

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

.footer-contact-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-contact-list a {
  font-size: 0.875rem;
  color: var(--text-secondary);
  text-decoration: none;
  transition: color var(--transition-speed) ease;
  font-family: var(--font-mono);
}

.footer-contact-list a:hover {
  color: var(--accent-green);
}

.footer-note {
  margin-top: 0.75rem;
  font-size: 0.75rem;
  color: var(--neutral-gray);
  line-height: 1.5;
}

.footer-bottom {
  margin-top: 2.5rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--glass-light);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1rem 2rem;
  font-size: 0.75rem;
  color: var(--neutral-gray);
  max-width: 1200px;
  margin-left: auto;
  margin-right: auto;
}

.footer-copyright {
  font-family: var(--font-mono);
}

.footer-icp {
  font-family: var(--font-mono);
  color: var(--text-secondary);
}

.footer-address {
  font-style: normal;
  font-size: 0.7rem;
  color: var(--neutral-gray);
  font-family: var(--font-mono);
}

/* Container */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.625rem 1.5rem;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 600;
  text-decoration: none;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: background-color var(--transition-speed) ease, color var(--transition-speed) ease, box-shadow var(--transition-speed) ease, transform 0.2s ease;
  letter-spacing: 0.03em;
}

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

.btn:active {
  transform: translateY(0);
}

.btn-primary {
  background-color: var(--accent-green);
  color: var(--bg-primary);
  box-shadow: 0 0 16px rgba(57,255,20,0.25);
}

.btn-primary:hover {
  background-color: #5cff3a;
  box-shadow: 0 0 24px rgba(57,255,20,0.4);
  color: var(--bg-primary);
}

.btn-secondary {
  background-color: transparent;
  color: var(--accent-blue);
  border: 1px solid var(--accent-blue);
  box-shadow: 0 0 8px rgba(0,191,255,0.15);
}

.btn-secondary:hover {
  background-color: rgba(0,191,255,0.1);
  box-shadow: 0 0 16px rgba(0,191,255,0.3);
}

/* Section Title */
.section-title {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 2rem;
  line-height: 1.2;
  margin-bottom: 1.5rem;
  letter-spacing: -0.02em;
}

.section-title .highlight {
  color: var(--accent-green);
}

/* Text Mono */
.text-mono {
  font-family: var(--font-mono);
}

/* Visually Hidden */
.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;
}

/* Fade In Animation */
.fade-in {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in-visible {
  opacity: 1;
  transform: translateY(0);
}

/* Responsive */
@media (max-width: 1023.98px) {
  .site-header {
    position: relative;
    width: 100%;
    height: auto;
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
    background: var(--bg-primary);
    border-right: none;
    border-bottom: 1px solid var(--glass-light);
  }

  .header-mobile-bar {
    display: flex;
  }

  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: fixed;
    top: 0;
    left: 0;
    width: var(--nav-width-mobile);
    height: 100vh;
    background: linear-gradient(135deg, rgba(13,13,13,0.98), rgba(26,26,26,0.95));
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-right: 1px solid var(--glass-medium);
    transform: translateX(-100%);
    opacity: 0;
    visibility: hidden;
    transition: transform 0.35s cubic-bezier(0.22, 1, 0.36, 1), opacity 0.35s ease, visibility 0.35s ease;
    z-index: var(--z-nav);
    padding: 1.5rem 0;
    overflow-y: auto;
  }

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

  .nav-overlay {
    display: block;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.6);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    z-index: calc(var(--z-overlay) - 1);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.35s ease, visibility 0.35s ease;
  }

  .nav-overlay[data-open] {
    opacity: 1;
    visibility: visible;
  }

  .site-main {
    margin-left: 0;
    padding: 1.5rem 1.25rem;
    max-width: 100%;
  }

  .site-footer {
    margin-left: 0;
    padding: 2rem 1.25rem 1.25rem;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
  }

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

@media (max-width: 639.98px) {
  .site-main {
    padding: 1rem;
  }

  .site-footer {
    padding: 1.5rem 1rem 1rem;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }

  .section-title {
    font-size: 1.5rem;
  }

  .nav-list a {
    padding: 0.5rem 0.75rem;
    font-size: 0.8125rem;
  }

  .nav-brand {
    padding: 0 1rem 1.5rem;
  }

  .nav-list {
    padding: 0 0.75rem;
  }

  .nav-footer {
    padding: 1rem 1rem 0;
  }
}

@media (min-width: 1024px) {
  .nav-toggle {
    display: none !important;
  }
  .header-mobile-bar {
    display: none !important;
  }
  .nav-overlay {
    display: none !important;
  }
}

/* Scrollbar styling */
.site-nav::-webkit-scrollbar {
  width: 4px;
}
.site-nav::-webkit-scrollbar-track {
  background: transparent;
}
.site-nav::-webkit-scrollbar-thumb {
  background: var(--glass-medium);
  border-radius: 2px;
}
.site-nav::-webkit-scrollbar-thumb:hover {
  background: var(--neutral-gray);
}

/* High contrast helper */
@media (prefers-contrast: high) {
  .nav-list a[aria-current="page"] {
    background-color: rgba(57,255,20,0.25);
    border-left: 3px solid var(--accent-green);
  }
  .btn-primary {
    border: 2px solid var(--bg-primary);
  }
  .btn-secondary {
    border: 2px solid var(--accent-blue);
  }
}