:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-card: #1a1a2e;
  --bg-hover: #222244;
  --purple-400: #a78bfa;
  --purple-500: #8b5cf6;
  --purple-600: #7c3aed;
  --purple-700: #6d28d9;
  --purple-900: #2e1065;
  --purple-glow: rgba(124, 58, 237, 0.15);
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --text-primary: #e5e7eb;
  --text-secondary: #9ca3af;
  --border-color: #1e1e3a;
  --sidebar-width: 280px;
  --header-height: 56px;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + 24px);
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
}

::selection {
  background: var(--purple-600);
  color: white;
}

/* Scrollbar */
::-webkit-scrollbar {
  width: 6px;
}
::-webkit-scrollbar-track {
  background: var(--bg-primary);
}
::-webkit-scrollbar-thumb {
  background: var(--purple-700);
  border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--purple-600);
}

/* Header */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: rgba(10, 10, 15, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 0 16px;
  z-index: 100;
}

.header-brand {
  display: flex;
  align-items: center;
  font-weight: 700;
  font-size: 16px;
  color: var(--purple-400);
  text-decoration: none;
  letter-spacing: -0.5px;
  flex-shrink: 0;
}

.header-brand .brand-accent {
  color: var(--text-primary);
}

.header-lang {
  display: flex;
  gap: 4px;
  margin-left: auto;
  flex-shrink: 0;
}

.lang-btn {
  background: transparent;
  border: 1px solid var(--gray-700);
  color: var(--gray-500);
  padding: 4px 10px;
  font-size: 12px;
  font-family: 'JetBrains Mono', monospace;
  cursor: pointer;
  border-radius: 4px;
  transition: all 0.2s;
}

.lang-btn:hover {
  border-color: var(--purple-600);
  color: var(--purple-400);
}

.lang-btn.active {
  background: var(--purple-700);
  border-color: var(--purple-700);
  color: white;
}

.menu-toggle {
  display: none;
  background: transparent;
  border: 1px solid var(--gray-700);
  color: var(--text-primary);
  padding: 6px 10px;
  cursor: pointer;
  border-radius: 4px;
  font-size: 18px;
}

/* Layout */
.layout {
  display: flex;
  min-height: 100vh;
  padding-top: var(--header-height);
}

/* Sidebar */
.sidebar {
  position: fixed;
  top: var(--header-height);
  left: 0;
  bottom: 0;
  width: var(--sidebar-width);
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  overflow-y: auto;
  overflow-x: hidden;
  padding: 16px 0;
  z-index: 50;
  transition: transform 0.3s ease;
}

.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  z-index: 49;
}

/* Tree Navigation */
.tree { list-style: none; }

.tree-item {
  user-select: none;
}

.tree-link {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 13px;
  cursor: pointer;
  transition: all 0.15s;
  border-left: 2px solid transparent;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.tree-link:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.tree-link.active {
  color: var(--purple-400);
  border-left-color: var(--purple-500);
  background: rgba(124, 58, 237, 0.08);
}

.tree-link.section-link {
  font-weight: 600;
  font-size: 14px;
  color: var(--text-primary);
  padding: 10px 16px;
  letter-spacing: 0.3px;
  text-transform: uppercase;
}

.tree-link.section-link .tree-icon {
  font-size: 16px;
}

.tree-link.category-link {
  padding-left: 36px;
}

.tree-link.project-link {
  padding-left: 56px;
  font-size: 12px;
}

.tree-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 16px;
  height: 16px;
  font-size: 10px;
  color: var(--gray-600);
  transition: transform 0.2s;
  flex-shrink: 0;
}

.tree-toggle.expanded {
  transform: rotate(90deg);
}

.tree-children {
  overflow: hidden;
  max-height: 0;
  transition: max-height 0.3s ease;
}

.tree-children.open {
  max-height: 2000px;
}

.tree-link.inline-cat {
  padding-left: 36px;
  font-size: 13px;
  color: var(--text-secondary);
}

.tree-link.inline-cat:hover {
  color: var(--text-primary);
}

.tree-link.inline-cat .tree-icon {
  flex-shrink: 0;
}

.category-block.inline-category .project-card-title {
  color: var(--purple-400);
  font-weight: 600;
}

/* Main Content */
.main {
  margin-left: var(--sidebar-width);
  flex: 1;
  padding: 32px 40px 80px;
  max-width: 960px;
}

/* Hero */
.hero-subtitle {
  color: var(--text-secondary);
  font-size: 12px;
  font-family: 'JetBrains Mono', monospace;
  white-space: nowrap;
}

.hero-tagline {
  color: var(--gray-600);
  font-size: 11px;
  white-space: nowrap;
}

.hero-links {
  display: flex;
  gap: 4px;
  flex-shrink: 0;
}

.hero-link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  color: var(--gray-400);
  text-decoration: none;
  font-size: 11px;
  padding: 4px 8px;
  border: 1px solid var(--gray-700);
  border-radius: 4px;
  transition: all 0.2s;
}

.hero-link:hover {
  border-color: var(--purple-600);
  color: var(--purple-400);
  background: rgba(124, 58, 237, 0.08);
}

/* Section */
.content-section {
  display: none;
  scroll-margin-top: calc(var(--header-height) + 24px);
}

.content-section.active {
  display: block;
  animation: fadeIn 0.3s ease;
}

.hidden { display: none !important; }

#project-detail.active { display: block; animation: fadeIn .3s ease; }

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.section-header {
  margin-bottom: 32px;
}

.detail-card{background:var(--bg-card);border:1px solid var(--border-color);border-radius:12px;padding:32px;animation:fadeIn .3s ease}.detail-card:hover{border-color:var(--purple-700);box-shadow:0 0 30px var(--purple-glow)}
.breadcrumb{font-size:12px;color:var(--gray-600);font-family:"JetBrains Mono",monospace;margin-bottom:16px}
.page-title{font-size:28px;font-weight:700;margin-bottom:16px}
.page-desc{font-size:15px;color:var(--text-secondary);line-height:1.7;margin-bottom:24px;padding-bottom:24px;border-bottom:1px solid var(--border-color)}
.meta-section{margin-bottom:12px}.meta-label{font-size:11px;color:var(--gray-600);font-family:"JetBrains Mono",monospace;text-transform:uppercase;letter-spacing:1px;margin-bottom:4px}
.back-link{display:inline-block;margin-bottom:24px;color:var(--purple-500);text-decoration:none;font-size:13px;font-family:"JetBrains Mono",monospace}.back-link:hover{color:var(--purple-400)}
.page-links a{display:inline-block;margin-right:12px;color:var(--purple-500);text-decoration:none;font-size:14px}.page-links a:hover{color:var(--purple-400);text-decoration:underline}

.section-title {
  font-size: 28px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.section-count {
  font-size: 12px;
  color: var(--gray-600);
  font-family: 'JetBrains Mono', monospace;
}

/* Category */
.category-block {
  margin-bottom: 36px;
}

.category-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--purple-400);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}

/* Project Card */
.project-grid {
  display: grid;
  gap: 12px;
}

.project-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 16px 20px;
  transition: all 0.2s;
  position: relative;
}

.project-card:hover {
  border-color: var(--purple-700);
  box-shadow: 0 0 20px var(--purple-glow);
  transform: translateY(-1px);
}

.project-card-title {
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 4px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.project-card-desc {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: 10px;
}

.project-card-meta {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.project-card-tag {
  font-size: 10px;
  padding: 2px 8px;
  border-radius: 10px;
  background: rgba(124, 58, 237, 0.12);
  color: var(--purple-400);
  font-family: 'JetBrains Mono', monospace;
}

.project-card-date {
  font-size: 10px;
  color: var(--gray-600);
  font-family: 'JetBrains Mono', monospace;
}

.project-card-links {
  display: flex;
  gap: 8px;
  margin-top: 8px;
}

.project-card-link {
  font-size: 12px;
  color: var(--purple-500);
  text-decoration: none;
  transition: color 0.15s;
}

.project-card-link:hover {
  color: var(--purple-400);
  text-decoration: underline;
}

.project-card {
  cursor: pointer;
}

.project-card-detail-link {
  margin-top: 10px;
  font-size: 12px;
  color: var(--purple-500);
  font-family: 'JetBrains Mono', monospace;
  transition: color 0.15s;
}

.project-card:hover .project-card-detail-link {
  color: var(--purple-400);
}

/* Project Detail */
.project-back-link {
  display: inline-block;
  margin-bottom: 24px;
  color: var(--purple-500);
  text-decoration: none;
  font-size: 13px;
  font-family: 'JetBrains Mono', monospace;
  transition: color 0.15s;
  cursor: pointer;
}

.project-back-link:hover {
  color: var(--purple-400);
}

.project-detail {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 32px;
  animation: fadeIn 0.3s ease;
}

.project-detail:hover {
  border-color: var(--purple-700);
  box-shadow: 0 0 30px var(--purple-glow);
}

.project-detail-breadcrumb {
  font-size: 12px;
  color: var(--gray-600);
  font-family: 'JetBrains Mono', monospace;
  margin-bottom: 16px;
}

.project-detail-title {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--text-primary);
}

.project-detail-desc {
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 24px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border-color);
}

.project-detail-meta {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.project-detail-section {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.project-detail-label {
  font-size: 11px;
  color: var(--gray-600);
  font-family: 'JetBrains Mono', monospace;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.project-detail-link {
  color: var(--purple-500);
  text-decoration: none;
  font-size: 14px;
  transition: color 0.15s;
}

.project-detail-link:hover {
  color: var(--purple-400);
  text-decoration: underline;
}

.project-detail-date {
  font-size: 14px;
  color: var(--text-secondary);
  font-family: 'JetBrains Mono', monospace;
}

/* Footer */
.footer {
  text-align: center;
  padding: 32px 20px;
  border-top: 1px solid var(--border-color);
  margin-top: 48px;
  margin-left: var(--sidebar-width);
}

@media (max-width: 768px) {
  .footer {
    margin-left: 0;
  }
}

.footer-text {
  font-size: 12px;
  color: var(--gray-600);
  font-family: 'JetBrains Mono', monospace;
}

/* Responsive */
@media (max-width: 768px) {
  .menu-toggle {
    display: block;
  }

  .sidebar {
    transform: translateX(-100%);
  }

  .sidebar.open {
    transform: translateX(0);
  }

  .sidebar-overlay.open {
    display: block;
  }

  .main {
    margin-left: 0;
    padding: 24px 16px 40px;
  }

  .project-grid {
    grid-template-columns: 1fr;
  }

  .header {
    gap: 6px;
    padding: 0 8px;
    overflow-x: auto;
  }

  .hero-subtitle, .hero-tagline {
    display: none;
  }
}

@media (min-width: 769px) and (max-width: 1024px) {
  .main {
    padding: 24px 24px 60px;
  }
}

/* Empty state */
.empty-state {
  text-align: center;
  padding: 32px;
  color: var(--gray-600);
  font-size: 13px;
}

/* Glitch effect for brand */
@keyframes glitch {
  0% { text-shadow: 2px 0 var(--purple-600), -2px 0 var(--purple-400); }
  25% { text-shadow: -2px 0 var(--purple-600), 2px 0 var(--purple-400); }
  50% { text-shadow: 1px 0 var(--purple-600), -1px 0 var(--purple-400); }
  75% { text-shadow: -1px 0 var(--purple-600), 1px 0 var(--purple-400); }
  100% { text-shadow: 0 0 transparent; }
}

.header-brand:hover .brand-accent {
  animation: glitch 0.3s ease 2;
}