/* ==========================================================================
   Yi-Ting Lin Portfolio - Blueprint/Schematic Aesthetic
   Technical Drawing | Architect's Workspace
   ========================================================================== */

/* --------------------------------------------------------------------------
   CSS Custom Properties
   -------------------------------------------------------------------------- */
:root {
  /* Blueprint Colors */
  --bg-primary: #0a0e14;
  --bg-secondary: #0c1018;
  --bg-card: #0c1219;
  --bg-panel: rgba(10, 14, 20, 0.95);

  /* Grid System */
  --grid-major: rgba(0, 180, 216, 0.12);
  --grid-minor: rgba(0, 180, 216, 0.04);
  --grid-accent: rgba(0, 217, 255, 0.25);

  /* Text Hierarchy - Enhanced Contrast */
  --text-primary: #f0f6fc;
  --text-secondary: #a8b2bc;
  --text-muted: #6e7a86;
  --text-dim: #3d444d;

  /* Accent System */
  --accent-cyan: #00d9ff;
  --accent-cyan-dim: rgba(0, 217, 255, 0.12);
  --accent-cyan-glow: rgba(0, 217, 255, 0.4);
  --accent-white: rgba(255, 255, 255, 0.9);

  /* Category Colors - Technical Palette */
  --cat-web3: #00d9ff;
  --cat-fullstack: #4ade80;
  --cat-ai: #a855f7;
  --cat-game: #f87171;
  --cat-tools: #fbbf24;
  --cat-other: #6b7280;

  /* Specification Colors */
  --spec-label: #00d9ff;
  --spec-value: #e6edf3;
  --spec-unit: #6b7280;

  /* Typography - Engineering Precision */
  --font-mono: 'IBM Plex Mono', 'Consolas', monospace;
  --font-sans: 'IBM Plex Sans', -apple-system, sans-serif;
  --font-technical: 'IBM Plex Mono', monospace;

  /* Spacing Grid (8px base) */
  --unit: 8px;
  --space-xs: calc(var(--unit) * 0.5);
  --space-sm: var(--unit);
  --space-md: calc(var(--unit) * 2);
  --space-lg: calc(var(--unit) * 3);
  --space-xl: calc(var(--unit) * 4);
  --space-2xl: calc(var(--unit) * 6);
  --space-3xl: calc(var(--unit) * 8);

  /* Blueprint Line Weights */
  --line-hairline: 0.5px;
  --line-thin: 1px;
  --line-medium: 1.5px;
  --line-thick: 2px;

  /* Transitions */
  --transition-fast: 120ms ease-out;
  --transition-base: 200ms ease-out;
  --transition-slow: 350ms ease-out;
}

/* --------------------------------------------------------------------------
   Reset & Base
   -------------------------------------------------------------------------- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* --------------------------------------------------------------------------
   Blueprint Grid Background - Technical Drawing Paper
   -------------------------------------------------------------------------- */
.grid-bg {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: -1;

  /* Layered grid system - major (64px) + minor (16px) */
  background-image:
    /* Vignette overlay for depth */
    radial-gradient(ellipse at center, transparent 0%, var(--bg-primary) 85%),
    /* Major grid lines */
    linear-gradient(var(--grid-major) var(--line-hairline), transparent var(--line-hairline)),
    linear-gradient(90deg, var(--grid-major) var(--line-hairline), transparent var(--line-hairline)),
    /* Minor grid lines */
    linear-gradient(var(--grid-minor) var(--line-hairline), transparent var(--line-hairline)),
    linear-gradient(90deg, var(--grid-minor) var(--line-hairline), transparent var(--line-hairline));

  background-size:
    100% 100%,
    64px 64px,
    64px 64px,
    16px 16px,
    16px 16px;

  background-position: center, -1px -1px, -1px -1px, -1px -1px, -1px -1px;
}

/* Animated scan line effect */
.grid-bg::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg,
    transparent 0%,
    var(--accent-cyan) 20%,
    var(--accent-cyan) 80%,
    transparent 100%
  );
  opacity: 0.4;
  animation: scanLine 6s linear infinite;
  box-shadow: 0 0 20px var(--accent-cyan-glow), 0 0 40px var(--accent-cyan-dim);
}

@keyframes scanLine {
  0% { transform: translateY(-100vh); opacity: 0; }
  5% { opacity: 0.4; }
  95% { opacity: 0.4; }
  100% { transform: translateY(100vh); opacity: 0; }
}

/* Corner registration marks - all four corners */
.grid-bg::after {
  content: '';
  position: fixed;
  top: 20px;
  left: 20px;
  width: 40px;
  height: 40px;
  border-left: var(--line-thin) solid var(--grid-accent);
  border-top: var(--line-thin) solid var(--grid-accent);
  opacity: 0.5;
  box-shadow:
    calc(100vw - 80px) 0 0 0 var(--grid-accent),
    0 calc(100vh - 80px) 0 0 var(--grid-accent),
    calc(100vw - 80px) calc(100vh - 80px) 0 0 var(--grid-accent);
}

/* Crosshair overlay element */
body::before {
  content: '';
  position: fixed;
  top: 50%;
  left: 50%;
  width: 100px;
  height: 100px;
  transform: translate(-50%, -50%);
  pointer-events: none;
  z-index: 1000;
  opacity: 0;
  transition: opacity 0.3s ease;
  background:
    linear-gradient(var(--accent-cyan) 0%, var(--accent-cyan) 100%) no-repeat center/1px 100%,
    linear-gradient(90deg, var(--accent-cyan) 0%, var(--accent-cyan) 100%) no-repeat center/100% 1px;
}

/* Technical drawing border frame */
body::after {
  content: '';
  position: fixed;
  top: 12px;
  left: 12px;
  right: 12px;
  bottom: 12px;
  border: var(--line-hairline) solid var(--grid-accent);
  pointer-events: none;
  z-index: 9999;
  opacity: 0.3;
}

/* --------------------------------------------------------------------------
   Technical Section Headers
   -------------------------------------------------------------------------- */
.section-header {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
  position: relative;
}

.section-label {
  font-family: var(--font-technical);
  font-size: 0.6875rem;
  font-weight: 500;
  letter-spacing: 0.2em;
  color: var(--accent-cyan);
  text-transform: uppercase;
  white-space: nowrap;
  position: relative;
  padding-left: var(--space-md);
}

/* Section marker */
.section-label::before {
  content: '◇';
  position: absolute;
  left: 0;
  font-size: 0.5rem;
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

.section-line {
  flex: 1;
  height: var(--line-hairline);
  background: linear-gradient(90deg,
    var(--accent-cyan) 0%,
    var(--grid-major) 20%,
    transparent 100%
  );
  position: relative;
}

/* Measurement ticks on section line */
.section-line::before {
  content: '';
  position: absolute;
  left: 0;
  top: -3px;
  width: 100%;
  height: 7px;
  background-image: repeating-linear-gradient(
    90deg,
    var(--grid-major) 0px,
    var(--grid-major) var(--line-hairline),
    transparent var(--line-hairline),
    transparent 32px
  );
}

/* --------------------------------------------------------------------------
   Hero Section - Main Schematic
   -------------------------------------------------------------------------- */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-xl);
  position: relative;
}

/* Blueprint frame around hero */
.hero::before {
  content: '';
  position: absolute;
  top: 40px;
  left: 40px;
  right: 40px;
  bottom: 40px;
  border: var(--line-hairline) solid var(--grid-major);
  pointer-events: none;
}

.hero-panel {
  position: relative;
  padding: var(--space-3xl);
  border: var(--line-thin) solid var(--grid-accent);
  max-width: 640px;
  width: 100%;
  text-align: center;
  background: var(--bg-panel);
  backdrop-filter: blur(12px);
}

/* Technical corner brackets */
.panel-corner {
  position: absolute;
  width: 16px;
  height: 16px;
  border-color: var(--accent-cyan);
  border-style: solid;
}

.panel-corner--tl {
  top: -1px;
  left: -1px;
  border-width: var(--line-medium) 0 0 var(--line-medium);
}

.panel-corner--tr {
  top: -1px;
  right: -1px;
  border-width: var(--line-medium) var(--line-medium) 0 0;
}

.panel-corner--bl {
  bottom: -1px;
  left: -1px;
  border-width: 0 0 var(--line-medium) var(--line-medium);
}

.panel-corner--br {
  bottom: -1px;
  right: -1px;
  border-width: 0 var(--line-medium) var(--line-medium) 0;
}

/* Coordinate labels */
.coord {
  position: absolute;
  font-family: var(--font-technical);
  font-size: 0.5625rem;
  color: var(--text-dim);
  letter-spacing: 0.1em;
}

.coord--tl {
  top: var(--space-sm);
  left: var(--space-sm);
}

.coord--br {
  bottom: var(--space-sm);
  right: var(--space-sm);
}

/* Designation tag */
.designation {
  display: inline-block;
  font-family: var(--font-technical);
  font-size: 0.5625rem;
  font-weight: 500;
  letter-spacing: 0.2em;
  color: var(--text-muted);
  text-transform: uppercase;
  margin-bottom: var(--space-lg);
  padding: var(--space-xs) var(--space-md);
  border: var(--line-hairline) solid var(--grid-accent);
  background: rgba(0, 217, 255, 0.03);
}

/* Main identifier */
.hero-name {
  font-family: var(--font-technical);
  font-size: clamp(1.75rem, 5vw, 2.75rem);
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-md);
  letter-spacing: 0.02em;
}

.cursor {
  color: var(--accent-cyan);
  animation: cursorBlink 1s step-end infinite;
  text-shadow: 0 0 10px var(--accent-cyan-glow);
}

@keyframes cursorBlink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}

.hero-title {
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 400;
  color: var(--text-secondary);
  margin-bottom: var(--space-xs);
  letter-spacing: 0.05em;
}

.hero-subtitle {
  font-family: var(--font-technical);
  font-size: 0.6875rem;
  color: var(--text-muted);
  letter-spacing: 0.08em;
  margin-bottom: var(--space-sm);
}

.hero-focus {
  font-family: var(--font-technical);
  font-size: 0.75rem;
  color: var(--text-muted);
  letter-spacing: 0.1em;
  margin-bottom: var(--space-md);
}

.hero-quote {
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  font-style: italic;
  color: var(--accent-cyan);
  opacity: 0.7;
  margin-bottom: var(--space-xl);
  padding: var(--space-sm) var(--space-md);
  border-left: var(--line-thin) solid var(--accent-cyan);
  text-align: left;
  max-width: 380px;
  margin-left: auto;
  margin-right: auto;
}

/* Action buttons */
.hero-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  justify-content: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  font-family: var(--font-technical);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.05em;
  text-decoration: none;
  text-transform: uppercase;
  padding: var(--space-sm) var(--space-md);
  border: var(--line-thin) solid var(--grid-accent);
  transition: all var(--transition-base);
  cursor: pointer;
  background: transparent;
  position: relative;
}

.btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 0;
  height: 100%;
  background: var(--accent-cyan);
  transition: width var(--transition-base);
  z-index: -1;
}

.btn-icon {
  font-size: 0.8125rem;
}

.btn--primary {
  color: var(--bg-primary);
  background: var(--accent-cyan);
  border-color: var(--accent-cyan);
}

.btn--primary:hover {
  background: transparent;
  color: var(--accent-cyan);
  box-shadow: 0 0 20px var(--accent-cyan-glow), inset 0 0 20px var(--accent-cyan-dim);
}

.btn--secondary {
  color: var(--accent-cyan);
  border-color: var(--accent-cyan);
}

.btn--secondary:hover {
  color: var(--bg-primary);
}

.btn--secondary:hover::before {
  width: 100%;
}

.btn--ghost {
  color: var(--text-secondary);
  border-color: transparent;
}

.btn--ghost:hover {
  color: var(--accent-cyan);
}

.btn-arrow {
  transition: transform var(--transition-base);
}

.btn--ghost:hover .btn-arrow {
  transform: translateY(4px);
  animation: bounce 0.6s ease infinite;
}

@keyframes bounce {
  0%, 100% { transform: translateY(4px); }
  50% { transform: translateY(8px); }
}

/* --------------------------------------------------------------------------
   Skills Section - Node Network
   -------------------------------------------------------------------------- */
.skills {
  padding: var(--space-3xl) var(--space-xl);
  max-width: 1000px;
  margin: 0 auto;
  position: relative;
}

.skills-container {
  display: flex;
  flex-direction: column;
  gap: var(--space-2xl);
  position: relative;
}

/* Connection lines between skill groups */
.skills-container::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: var(--line-hairline);
  background: repeating-linear-gradient(
    to bottom,
    var(--grid-accent) 0px,
    var(--grid-accent) 4px,
    transparent 4px,
    transparent 8px
  );
}

.skills-group {
  position: relative;
  padding-left: var(--space-lg);
}

/* Node connector */
.skills-group::before {
  content: '';
  position: absolute;
  left: -4px;
  top: 8px;
  width: 8px;
  height: 8px;
  border: var(--line-thin) solid var(--accent-cyan);
  background: var(--bg-primary);
  transform: rotate(45deg);
}

.skills-group::after {
  content: '';
  position: absolute;
  left: 4px;
  top: 12px;
  width: var(--space-md);
  height: var(--line-hairline);
  background: var(--grid-accent);
}

.skills-group-title {
  font-family: var(--font-technical);
  font-size: 0.625rem;
  font-weight: 500;
  letter-spacing: 0.15em;
  color: var(--text-muted);
  margin-bottom: var(--space-md);
  text-transform: uppercase;
}

.skills-chips {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

/* Skill chip as circuit node */
.chip {
  font-family: var(--font-technical);
  font-size: 0.6875rem;
  font-weight: 500;
  padding: var(--space-xs) var(--space-sm);
  border: var(--line-hairline) solid var(--grid-accent);
  color: var(--text-secondary);
  transition: all var(--transition-fast);
  cursor: default;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  position: relative;
  background: var(--bg-secondary);
}

/* Connection dots */
.chip::before {
  content: '';
  position: absolute;
  left: -3px;
  top: 50%;
  transform: translateY(-50%);
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--grid-accent);
  transition: all var(--transition-fast);
}

.chip:hover {
  transform: translateY(-2px);
  border-color: currentColor;
}

.chip:hover::before {
  background: currentColor;
  box-shadow: 0 0 8px currentColor;
}

.chip--lang:hover { color: var(--cat-web3); }
.chip--frontend:hover { color: var(--cat-game); }
.chip--backend:hover { color: var(--cat-fullstack); }
.chip--ml:hover { color: var(--cat-ai); }
.chip--devops:hover { color: var(--cat-tools); }
.chip--web3:hover { color: var(--cat-web3); }
.chip--tools:hover { color: var(--cat-tools); }

/* Certifications */
.certifications {
  margin-top: var(--space-2xl);
  padding-top: var(--space-lg);
  border-top: var(--line-hairline) dashed var(--grid-accent);
}

.cert-title {
  font-family: var(--font-technical);
  font-size: 0.625rem;
  font-weight: 500;
  letter-spacing: 0.15em;
  color: var(--text-muted);
  margin-bottom: var(--space-md);
  text-transform: uppercase;
}

.cert-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.cert-item {
  font-family: var(--font-technical);
  font-size: 0.6875rem;
  font-weight: 500;
  padding: var(--space-xs) var(--space-md);
  border: var(--line-hairline) solid var(--cat-tools);
  color: var(--cat-tools);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  background: rgba(251, 191, 36, 0.05);
}

.cert-item--lang {
  border-color: var(--accent-cyan);
  color: var(--accent-cyan);
  background: rgba(0, 217, 255, 0.05);
}

/* --------------------------------------------------------------------------
   Interactive Skill-Project Network Graph (D3.js)
   -------------------------------------------------------------------------- */
.network-view {
  padding: var(--space-3xl) var(--space-xl);
  max-width: 1000px;
  margin: 0 auto;
}

.network-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-xl);
}

.network-description {
  text-align: center;
}

.network-description p {
  font-family: var(--font-sans);
  font-size: 0.875rem;
  color: var(--text-secondary);
  font-style: italic;
}

/* Graph Canvas Container */
.network-graph-canvas {
  position: relative;
  width: 100%;
  min-height: 500px;
  border: var(--line-hairline) solid var(--grid-accent);
  background: var(--bg-card);
  overflow: hidden;
}

.network-graph-canvas svg {
  display: block;
  width: 100%;
  height: 100%;
}

/* Graph Links */
.graph-link {
  stroke-linecap: round;
  transition: stroke 0.2s ease, stroke-width 0.2s ease, opacity 0.2s ease;
}

.graph-link.primary {
  stroke-opacity: 0.6;
}

.graph-link.secondary {
  stroke-opacity: 0.3;
}

/* Graph Nodes */
.graph-node {
  transition: opacity 0.2s ease;
}

.graph-node--skill polygon {
  transition: all 0.2s ease;
}

.graph-node--skill:hover polygon {
  stroke-width: 3;
  filter: url(#glow);
}

.graph-node--project circle {
  transition: all 0.2s ease;
}

.graph-node--project:hover circle {
  stroke-width: 2.5;
  fill: rgba(0, 217, 255, 0.1);
}

/* Node Labels */
.node-label {
  pointer-events: none;
  user-select: none;
  text-shadow: 0 0 4px rgba(0, 0, 0, 0.8);
}

/* Graph Tooltip */
.graph-tooltip {
  position: absolute;
  padding: var(--space-sm) var(--space-md);
  background: var(--bg-secondary);
  border: var(--line-hairline) solid var(--accent-cyan);
  font-family: var(--font-technical);
  font-size: 0.75rem;
  color: var(--text-primary);
  pointer-events: none;
  z-index: 100;
  transition: opacity 0.15s ease;
  max-width: 200px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
}

.graph-tooltip strong {
  color: var(--accent-cyan);
  display: block;
  margin-bottom: 2px;
}

.graph-tooltip .tooltip-sub {
  color: var(--text-secondary);
  font-size: 0.625rem;
}

.graph-tooltip .tooltip-action {
  color: var(--accent-cyan);
  font-size: 0.5625rem;
  font-style: italic;
  margin-top: 4px;
  display: block;
}

/* Network Legend */
.network-legend {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-md);
  padding-top: var(--space-lg);
  border-top: var(--line-hairline) dashed var(--grid-accent);
}

.legend-item {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  font-family: var(--font-technical);
  font-size: 0.625rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.legend-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
}

.legend-dot--language { background: #60a5fa; }
.legend-dot--framework { background: #4ade80; }
.legend-dot--ai { background: #c084fc; }
.legend-dot--devops { background: #fbbf24; }
.legend-dot--project { background: #f0f6fc; }

/* Responsive adjustments for network */
@media (max-width: 640px) {
  .network-graph-canvas {
    min-height: 400px;
  }

  .network-legend {
    gap: var(--space-sm);
  }

  .legend-item {
    font-size: 0.5rem;
  }
}

/* --------------------------------------------------------------------------
   Experience Section - Timeline
   -------------------------------------------------------------------------- */
.experience {
  padding: var(--space-3xl) var(--space-xl);
  max-width: 900px;
  margin: 0 auto;
}

.experience-container {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.experience-card {
  position: relative;
  padding: var(--space-lg);
  border: var(--line-hairline) solid var(--grid-accent);
  background: var(--bg-card);
  padding-left: var(--space-2xl);
}

/* Timeline connector */
.experience-card::before {
  content: '';
  position: absolute;
  left: var(--space-md);
  top: 0;
  bottom: 0;
  width: var(--line-hairline);
  background: var(--grid-accent);
}

/* Timeline node */
.experience-card::after {
  content: '';
  position: absolute;
  left: calc(var(--space-md) - 4px);
  top: var(--space-lg);
  width: 9px;
  height: 9px;
  border: var(--line-thin) solid var(--cat-fullstack);
  background: var(--bg-primary);
  transform: rotate(45deg);
}

.experience-card--research::after {
  border-color: var(--cat-ai);
}

.exp-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-xs);
}

.exp-title {
  font-family: var(--font-technical);
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: 0.02em;
}

.exp-date {
  font-family: var(--font-technical);
  font-size: 0.6875rem;
  color: var(--accent-cyan);
  letter-spacing: 0.05em;
}

.exp-company {
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  color: var(--text-secondary);
  margin-bottom: var(--space-md);
}

.exp-details {
  list-style: none;
  padding: 0;
}

.exp-details li {
  position: relative;
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  color: var(--text-secondary);
  line-height: 1.6;
  padding-left: var(--space-md);
  margin-bottom: var(--space-xs);
}

.exp-details li::before {
  content: '>';
  position: absolute;
  left: 0;
  color: var(--accent-cyan);
  font-family: var(--font-technical);
  font-size: 0.75rem;
}

/* Experience tech tags */
.exp-tech {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  margin-top: var(--space-md);
  padding-top: var(--space-md);
  border-top: var(--line-hairline) dashed var(--grid-accent);
}

.exp-tech span {
  font-family: var(--font-technical);
  font-size: 0.5625rem;
  font-weight: 500;
  padding: 2px var(--space-sm);
  border: var(--line-hairline) solid var(--grid-accent);
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  background: var(--bg-secondary);
}

/* Experience badges */
.exp-badge {
  position: absolute;
  top: 0;
  right: 0;
  font-family: var(--font-technical);
  font-size: 0.5rem;
  font-weight: 600;
  letter-spacing: 0.15em;
  padding: var(--space-xs) var(--space-sm);
  background: var(--cat-fullstack);
  color: var(--bg-primary);
  text-transform: uppercase;
}

.exp-badge--award {
  background: var(--cat-ai);
}

/* Current job highlight */
.experience-card--current {
  border-color: var(--cat-fullstack);
  background: linear-gradient(135deg, var(--bg-card) 0%, rgba(74, 222, 128, 0.03) 100%);
}

.experience-card--current::after {
  border-color: var(--cat-fullstack);
  background: var(--cat-fullstack);
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(74, 222, 128, 0.4); }
  50% { box-shadow: 0 0 0 8px rgba(74, 222, 128, 0); }
}

/* --------------------------------------------------------------------------
   Projects Section - Technical Specifications Grid
   -------------------------------------------------------------------------- */
.projects {
  padding: var(--space-3xl) var(--space-xl);
  max-width: 1200px;
  margin: 0 auto;
}

/* Filter Tabs - Mode Selector */
.filter-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  margin-bottom: var(--space-xl);
  padding: var(--space-xs);
  border: var(--line-hairline) solid var(--grid-accent);
  background: var(--bg-secondary);
}

.filter-tab {
  font-family: var(--font-technical);
  font-size: 0.6875rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: var(--space-xs) var(--space-md);
  border: var(--line-hairline) solid transparent;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  transition: all var(--transition-fast);
  position: relative;
}

.filter-tab:hover {
  color: var(--accent-cyan);
}

.filter-tab.active {
  background: var(--accent-cyan);
  border-color: var(--accent-cyan);
  color: var(--bg-primary);
}

/* Active indicator */
.filter-tab.active::after {
  content: '';
  position: absolute;
  bottom: -6px;
  left: 50%;
  transform: translateX(-50%);
  width: 0;
  height: 0;
  border-left: 4px solid transparent;
  border-right: 4px solid transparent;
  border-top: 4px solid var(--accent-cyan);
}

/* Projects Grid */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--space-md);
}

/* Project Card - Technical Specification Sheet */
.project-card {
  position: relative;
  background: var(--bg-card);
  border: var(--line-hairline) solid var(--grid-accent);
  padding: var(--space-lg);
  transition: all var(--transition-base);
  overflow: hidden;
}

/* Index number */
.project-card::before {
  content: attr(data-index);
  position: absolute;
  top: var(--space-sm);
  right: var(--space-sm);
  font-family: var(--font-technical);
  font-size: 0.5rem;
  color: var(--text-dim);
  letter-spacing: 0.1em;
}

/* Corner detail */
.project-card::after {
  content: '';
  position: absolute;
  bottom: 0;
  right: 0;
  width: 20px;
  height: 20px;
  border-left: var(--line-hairline) solid var(--grid-accent);
  border-top: var(--line-hairline) solid var(--grid-accent);
  opacity: 0.5;
}

.project-card:hover {
  transform: translateY(-4px);
  border-color: var(--accent-cyan);
  box-shadow:
    0 8px 32px rgba(0, 0, 0, 0.4),
    0 0 0 1px var(--accent-cyan-dim),
    inset 0 1px 0 var(--accent-cyan-dim);
}

.project-card.hidden {
  display: none;
}

/* Featured card highlight */
.project-card.featured {
  border-color: var(--cat-ai);
  background: linear-gradient(135deg, var(--bg-card) 0%, rgba(168, 85, 247, 0.05) 100%);
}

.project-card.featured::before {
  display: none;
}

.card-badge {
  position: absolute;
  top: var(--space-sm);
  right: var(--space-sm);
  font-family: var(--font-technical);
  font-size: 0.5rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--cat-ai);
  padding: 2px var(--space-xs);
  border: var(--line-hairline) solid var(--cat-ai);
  background: rgba(168, 85, 247, 0.1);
}

/* Status indicator */
.card-indicator {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  margin-bottom: var(--space-md);
  position: relative;
}

.card-indicator::after {
  content: '';
  position: absolute;
  top: -2px;
  left: -2px;
  right: -2px;
  bottom: -2px;
  border-radius: 50%;
  border: var(--line-hairline) solid currentColor;
  opacity: 0.3;
}

.card-indicator--web3 { background: var(--cat-web3); color: var(--cat-web3); }
.card-indicator--fullstack { background: var(--cat-fullstack); color: var(--cat-fullstack); }
.card-indicator--ai { background: var(--cat-ai); color: var(--cat-ai); }
.card-indicator--game { background: var(--cat-game); color: var(--cat-game); }
.card-indicator--tools { background: var(--cat-tools); color: var(--cat-tools); }
.card-indicator--other { background: var(--cat-other); color: var(--cat-other); }

.card-title {
  font-family: var(--font-technical);
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
  transition: color var(--transition-fast);
  letter-spacing: 0.02em;
}

.project-card:hover .card-title {
  color: var(--accent-cyan);
}

.card-desc {
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  color: var(--text-secondary);
  margin-bottom: var(--space-md);
  line-height: 1.6;
}

/* Tech stack tags */
.card-tech {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  margin-bottom: var(--space-md);
}

.card-tech span {
  font-family: var(--font-technical);
  font-size: 0.5625rem;
  color: var(--text-muted);
  padding: 2px var(--space-xs);
  border: var(--line-hairline) solid var(--grid-accent);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  background: rgba(0, 217, 255, 0.02);
}

/* View link */
.card-link {
  font-family: var(--font-technical);
  font-size: 0.75rem;
  color: var(--accent-cyan);
  text-decoration: none;
  opacity: 0;
  transform: translateX(-8px);
  transition: all var(--transition-fast);
  letter-spacing: 0.05em;
}

.project-card:hover .card-link {
  opacity: 1;
  transform: translateX(0);
}

.card-link:hover {
  text-decoration: underline;
}

/* --------------------------------------------------------------------------
   Specification Panel (appears on hover) - Technical Data Sheet
   -------------------------------------------------------------------------- */
.card-specs {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(10, 14, 20, 0.98);
  padding: var(--space-md);
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-base);
  display: flex;
  flex-direction: column;
  justify-content: center;
  border: var(--line-thin) solid var(--accent-cyan);
  backdrop-filter: blur(8px);
  /* Technical drawing corner marks */
  background-image:
    linear-gradient(var(--accent-cyan) 0%, var(--accent-cyan) 100%),
    linear-gradient(var(--accent-cyan) 0%, var(--accent-cyan) 100%),
    linear-gradient(var(--accent-cyan) 0%, var(--accent-cyan) 100%),
    linear-gradient(var(--accent-cyan) 0%, var(--accent-cyan) 100%);
  background-size: 12px 1px, 1px 12px, 12px 1px, 1px 12px;
  background-position: top left, top left, bottom right, bottom right;
  background-repeat: no-repeat;
}

/* Animated reveal */
.project-card:hover .card-specs {
  opacity: 1;
  visibility: visible;
  animation: specReveal 0.3s ease-out;
}

@keyframes specReveal {
  from {
    clip-path: polygon(0 0, 0 0, 0 100%, 0 100%);
  }
  to {
    clip-path: polygon(0 0, 100% 0, 100% 100%, 0 100%);
  }
}

.spec-header {
  font-family: var(--font-technical);
  font-size: 0.5625rem;
  letter-spacing: 0.2em;
  color: var(--accent-cyan);
  text-transform: uppercase;
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-xs);
  border-bottom: var(--line-hairline) solid var(--grid-accent);
  position: relative;
}

/* Measurement tick marks */
.spec-header::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 0;
  width: 100%;
  height: 5px;
  background-image: repeating-linear-gradient(
    90deg,
    var(--grid-accent) 0px,
    var(--grid-accent) 1px,
    transparent 1px,
    transparent 20px
  );
}

.spec-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: var(--space-xs) 0;
  border-bottom: var(--line-hairline) dashed var(--grid-accent);
  position: relative;
}

/* Data point indicator */
.spec-row::before {
  content: '';
  position: absolute;
  left: -8px;
  top: 50%;
  transform: translateY(-50%);
  width: 3px;
  height: 3px;
  background: var(--accent-cyan);
  border-radius: 50%;
}

.spec-label {
  font-family: var(--font-technical);
  font-size: 0.625rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.spec-value {
  font-family: var(--font-technical);
  font-size: 0.75rem;
  color: var(--text-primary);
  text-align: right;
}

.spec-link {
  margin-top: var(--space-md);
  text-align: center;
}

.spec-link a {
  display: inline-block;
  font-family: var(--font-technical);
  font-size: 0.6875rem;
  color: var(--accent-cyan);
  text-decoration: none;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  padding: var(--space-xs) var(--space-md);
  border: var(--line-thin) solid var(--accent-cyan);
  transition: all var(--transition-fast);
  background: transparent;
}

.spec-link a:hover {
  background: var(--accent-cyan);
  color: var(--bg-primary);
  box-shadow: 0 0 12px var(--accent-cyan-glow);
}

/* --------------------------------------------------------------------------
   Footer - Technical Endnotes
   -------------------------------------------------------------------------- */
.footer {
  padding: var(--space-3xl) var(--space-xl);
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
  position: relative;
}

/* Top border with measurement marks */
.footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: var(--space-xl);
  right: var(--space-xl);
  height: var(--line-hairline);
  background: var(--grid-accent);
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.footer-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-xs);
  text-decoration: none;
  padding: var(--space-md);
  border: var(--line-hairline) solid var(--grid-accent);
  color: var(--text-secondary);
  transition: all var(--transition-base);
  min-width: 80px;
  background: var(--bg-secondary);
}

.footer-btn:hover {
  border-color: var(--accent-cyan);
  color: var(--accent-cyan);
  box-shadow: 0 0 20px var(--accent-cyan-dim);
}

.footer-icon {
  font-family: var(--font-technical);
  font-size: 1.125rem;
}

.footer-btn span:last-child {
  font-family: var(--font-technical);
  font-size: 0.625rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.footer-email {
  font-family: var(--font-technical);
  font-size: 0.8125rem;
  color: var(--text-muted);
  margin-bottom: var(--space-xl);
  letter-spacing: 0.05em;
}

.footer-divider {
  width: 48px;
  height: var(--line-hairline);
  background: var(--grid-accent);
  margin: 0 auto var(--space-lg);
}

.footer-copy {
  font-family: var(--font-technical);
  font-size: 0.6875rem;
  color: var(--text-dim);
  margin-bottom: var(--space-sm);
  letter-spacing: 0.05em;
}

.footer-source {
  font-family: var(--font-technical);
  font-size: 0.625rem;
  color: var(--text-dim);
  text-decoration: none;
  transition: color var(--transition-fast);
  letter-spacing: 0.05em;
}

.footer-source:hover {
  color: var(--accent-cyan);
}

/* --------------------------------------------------------------------------
   Animations
   -------------------------------------------------------------------------- */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(24px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes drawLine {
  from { width: 0; }
  to { width: 100%; }
}

.hero-panel {
  animation: fadeInUp 0.8s ease-out;
}

.skills-group {
  opacity: 0;
  animation: fadeInUp 0.5s ease-out forwards;
}

.skills-group:nth-child(1) { animation-delay: 0.1s; }
.skills-group:nth-child(2) { animation-delay: 0.2s; }
.skills-group:nth-child(3) { animation-delay: 0.3s; }

.project-card {
  opacity: 0;
  animation: fadeInUp 0.4s ease-out forwards;
}

/* Staggered animation */
.project-card:nth-child(1) { animation-delay: 0.05s; }
.project-card:nth-child(2) { animation-delay: 0.08s; }
.project-card:nth-child(3) { animation-delay: 0.11s; }
.project-card:nth-child(4) { animation-delay: 0.14s; }
.project-card:nth-child(5) { animation-delay: 0.17s; }
.project-card:nth-child(6) { animation-delay: 0.20s; }
.project-card:nth-child(7) { animation-delay: 0.23s; }
.project-card:nth-child(8) { animation-delay: 0.26s; }
.project-card:nth-child(9) { animation-delay: 0.29s; }
.project-card:nth-child(10) { animation-delay: 0.32s; }
.project-card:nth-child(11) { animation-delay: 0.35s; }
.project-card:nth-child(12) { animation-delay: 0.38s; }
.project-card:nth-child(13) { animation-delay: 0.41s; }
.project-card:nth-child(14) { animation-delay: 0.44s; }
.project-card:nth-child(15) { animation-delay: 0.47s; }
.project-card:nth-child(16) { animation-delay: 0.50s; }
.project-card:nth-child(17) { animation-delay: 0.53s; }
.project-card:nth-child(18) { animation-delay: 0.56s; }

/* --------------------------------------------------------------------------
   Responsive Design
   -------------------------------------------------------------------------- */
@media (max-width: 768px) {
  .hero::before {
    top: 20px;
    left: 20px;
    right: 20px;
    bottom: 20px;
  }

  .hero-panel {
    padding: var(--space-xl);
  }

  .hero-name {
    font-size: 1.5rem;
  }

  .hero-links {
    flex-direction: column;
    align-items: stretch;
  }

  .btn {
    justify-content: center;
  }

  .filter-tabs {
    justify-content: center;
  }

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

  .skills-container::before {
    display: none;
  }

  .skills-group {
    padding-left: 0;
  }

  .skills-group::before,
  .skills-group::after {
    display: none;
  }
}

@media (max-width: 480px) {
  .section-label {
    font-size: 0.5625rem;
  }

  .hero-focus {
    font-size: 0.6875rem;
  }

  .chip {
    font-size: 0.5625rem;
    padding: 2px var(--space-xs);
  }

  .filter-tab {
    font-size: 0.5625rem;
    padding: 4px var(--space-sm);
  }
}

/* --------------------------------------------------------------------------
   Scrollbar - Technical Style
   -------------------------------------------------------------------------- */
::-webkit-scrollbar {
  width: 6px;
}

::-webkit-scrollbar-track {
  background: var(--bg-primary);
  border-left: var(--line-hairline) solid var(--grid-accent);
}

::-webkit-scrollbar-thumb {
  background: var(--grid-accent);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--accent-cyan);
}

/* --------------------------------------------------------------------------
   Selection
   -------------------------------------------------------------------------- */
::selection {
  background: var(--accent-cyan);
  color: var(--bg-primary);
}

/* --------------------------------------------------------------------------
   Print Styles
   -------------------------------------------------------------------------- */
@media print {
  .grid-bg,
  .grid-bg::before,
  .grid-bg::after {
    display: none;
  }

  body {
    background: white;
    color: black;
  }

  .project-card {
    break-inside: avoid;
  }
}