/* ============================================================
   Portfolio CSS - Product Manager @ Meituan Ticket Marketing
   Dark-first design with glassmorphism, gradient mesh,
   micro-interactions, and responsive layout
   ============================================================ */

/* --- Google Fonts --- */
/* Google Fonts loaded via HTML link tag */

/* ============================================================
   1. CSS CUSTOM PROPERTIES - Dark Theme (Default)
   ============================================================ */
:root {
  /* Base palette */
  --bg-primary: #0a0a0f;
  --bg-secondary: #0d1117;
  --bg-tertiary: #161b22;
  --bg-elevated: #1c2128;
  --bg-surface: #21262d;

  /* Text */
  --text-primary: #f0f6fc;
  --text-secondary: #b1bac4;
  --text-tertiary: #7d8590;
  --text-muted: #484f58;

  /* Accent - Gold */
  --accent-primary: #d4a853;
  --accent-primary-bright: #f0c95c;
  --accent-primary-dim: #9e7c33;
  --accent-glow: rgba(212, 168, 83, 0.3);

  /* Accent - Cyan */
  --accent-secondary: #22d3ee;
  --accent-secondary-bright: #67e8f9;
  --accent-secondary-dim: #0e7490;
  --accent-secondary-glow: rgba(34, 211, 238, 0.25);

  /* Accent - Blue */
  --accent-blue: #3b82f6;

  /* Gradients */
  --gradient-gold: linear-gradient(135deg, #d4a853, #f0c95c);
  --gradient-cyan: linear-gradient(135deg, #22d3ee, #3b82f6);
  --gradient-text: linear-gradient(135deg, #f0c95c 0%, #d4a853 40%, #22d3ee 100%);
  --gradient-mesh-1: radial-gradient(ellipse at 20% 50%, rgba(212, 168, 83, 0.08) 0%, transparent 50%);
  --gradient-mesh-2: radial-gradient(ellipse at 80% 20%, rgba(34, 211, 238, 0.06) 0%, transparent 50%);
  --gradient-mesh-3: radial-gradient(ellipse at 50% 80%, rgba(59, 130, 246, 0.05) 0%, transparent 50%);

  /* Glass */
  --glass-bg: rgba(22, 27, 34, 0.6);
  --glass-border: rgba(240, 246, 252, 0.08);
  --glass-blur: 20px;
  --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);

  /* Borders */
  --border-default: rgba(240, 246, 252, 0.06);
  --border-hover: rgba(240, 246, 252, 0.12);
  --border-glow: rgba(212, 168, 83, 0.4);

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 5rem;
  --space-4xl: 7rem;

  /* Layout */
  --content-max-width: 1100px;
  --nav-height: 64px;

  /* Border radius */
  --border-radius-sm: 6px;
  --border-radius-md: 12px;
  --border-radius-lg: 20px;
  --border-radius-xl: 28px;
  --border-radius-full: 9999px;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-spring: 500ms cubic-bezier(0.34, 1.56, 0.64, 1);
}

/* ============================================================
   2. LIGHT THEME OVERRIDE
   ============================================================ */
[data-theme="light"] {
  --bg-primary: #f8f9fa;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f1f3f5;
  --bg-elevated: #ffffff;
  --bg-surface: #e9ecef;

  --text-primary: #1a1a2e;
  --text-secondary: #495057;
  --text-tertiary: #868e96;
  --text-muted: #adb5bd;

  --accent-primary: #b8941f;
  --accent-primary-bright: #d4a853;
  --accent-primary-dim: #8c6d0f;
  --accent-glow: rgba(184, 148, 31, 0.15);

  --accent-secondary: #0891b2;
  --accent-secondary-bright: #06b6d4;
  --accent-secondary-dim: #0e7490;
  --accent-secondary-glow: rgba(8, 145, 178, 0.12);

  --gradient-text: linear-gradient(135deg, #b8941f 0%, #8c6d0f 40%, #0891b2 100%);

  --glass-bg: rgba(255, 255, 255, 0.7);
  --glass-border: rgba(0, 0, 0, 0.06);
  --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.08);

  --border-default: rgba(0, 0, 0, 0.06);
  --border-hover: rgba(0, 0, 0, 0.12);
  --border-glow: rgba(184, 148, 31, 0.3);
}

/* ============================================================
   3. RESET AND BASE STYLES
   ============================================================ */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

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

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  background-image:
    var(--gradient-mesh-1),
    var(--gradient-mesh-2),
    var(--gradient-mesh-3);
  background-attachment: fixed;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

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

ul, ol {
  list-style: none;
}

/* ============================================================
   4. UTILITY CLASSES
   ============================================================ */
.container {
  width: 100%;
  max-width: var(--content-max-width);
  margin-inline: auto;
  padding-inline: var(--space-xl);
}

.text-gradient {
  background: var(--gradient-text);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.text-glow {
  text-shadow: 0 0 20px var(--accent-glow);
}

.glow-border {
  border: 1px solid var(--accent-primary);
  box-shadow: 0 0 20px var(--accent-glow);
}

.hidden {
  display: none !important;
}

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

/* ============================================================
   5. NAVIGATION - Sticky Glass Effect
   ============================================================ */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  z-index: 1000;
  display: flex;
  align-items: center;
  transition: background var(--transition-normal),
              border-color var(--transition-normal),
              box-shadow var(--transition-normal);
}

/* Subtle bottom glow line */
.nav::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 10%;
  right: 10%;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--border-glow), transparent);
  opacity: 0;
  transition: opacity var(--transition-normal);
}

/* Glass effect on scroll */
.nav.scrolled {
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border-bottom: 1px solid var(--glass-border);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
}

.nav.scrolled::after {
  opacity: 1;
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  max-width: var(--content-max-width);
  margin-inline: auto;
  padding-inline: var(--space-xl);
}

.nav-logo {
  font-weight: 800;
  font-size: 1.2rem;
  background: var(--gradient-text);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

.nav-link {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--border-radius-sm);
  position: relative;
  transition: color var(--transition-fast);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 2px;
  left: 50%;
  width: 0;
  height: 2px;
  background: var(--gradient-gold);
  border-radius: 1px;
  transition: width var(--transition-normal), left var(--transition-normal);
}

.nav-link:hover {
  color: var(--text-primary);
}

.nav-link:hover::after {
  width: 60%;
  left: 20%;
}

.nav-link.active {
  color: var(--accent-primary);
}

.nav-link.active::after {
  width: 60%;
  left: 20%;
}

/* Theme toggle button */
.theme-toggle {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  transition: transform var(--transition-spring),
              background var(--transition-fast),
              border-color var(--transition-fast);
}

.theme-toggle:hover {
  transform: scale(1.1) rotate(15deg);
  border-color: var(--accent-primary);
  box-shadow: 0 0 15px var(--accent-glow);
}

.theme-toggle svg {
  width: 18px;
  height: 18px;
}

/* Mobile menu toggle */
.nav-mobile-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
}

.nav-mobile-menu {
  position: fixed;
  inset: 0;
  background: var(--bg-primary);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-xl);
  z-index: 999;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-normal);
}

.nav-mobile-menu.open {
  opacity: 1;
  pointer-events: all;
}

.nav-mobile-menu a {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
}

/* ============================================================
   6. HERO SECTION - Full Viewport with Animated Mesh
   ============================================================ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding-top: var(--nav-height);
  overflow: hidden;
}

/* Animated gradient mesh background */
.hero-mesh {
  position: absolute;
  inset: 0;
  z-index: 0;
  background:
    radial-gradient(ellipse 80% 60% at 20% 40%, rgba(212, 168, 83, 0.1) 0%, transparent 60%),
    radial-gradient(ellipse 60% 80% at 80% 30%, rgba(34, 211, 238, 0.08) 0%, transparent 60%),
    radial-gradient(ellipse 70% 50% at 50% 80%, rgba(59, 130, 246, 0.06) 0%, transparent 50%);
  animation: meshFloat 20s ease-in-out infinite alternate;
}

@keyframes meshFloat {
  0% {
    transform: translate(0, 0) scale(1);
  }
  33% {
    transform: translate(2%, -2%) scale(1.02);
  }
  66% {
    transform: translate(-1%, 3%) scale(0.98);
  }
  100% {
    transform: translate(3%, 1%) scale(1.01);
  }
}

/* Floating geometric shapes */
.hero-shapes {
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  overflow: hidden;
}

.hero-shape {
  position: absolute;
  border: 1px solid var(--glass-border);
  background: var(--glass-bg);
  opacity: 0.4;
  animation: shapeFloat 15s ease-in-out infinite;
}

.hero-shape:nth-child(1) {
  width: 80px;
  height: 80px;
  top: 15%;
  left: 10%;
  border-radius: var(--border-radius-md);
  animation-duration: 18s;
  animation-delay: 0s;
}

.hero-shape:nth-child(2) {
  width: 120px;
  height: 120px;
  top: 60%;
  right: 10%;
  border-radius: 50%;
  animation-duration: 22s;
  animation-delay: -5s;
}

.hero-shape:nth-child(3) {
  width: 60px;
  height: 60px;
  bottom: 20%;
  left: 20%;
  border-radius: var(--border-radius-sm);
  transform: rotate(45deg);
  animation-duration: 16s;
  animation-delay: -8s;
}

.hero-shape:nth-child(4) {
  width: 100px;
  height: 100px;
  top: 25%;
  right: 20%;
  border-radius: var(--border-radius-lg);
  animation-duration: 20s;
  animation-delay: -3s;
}

.hero-shape:nth-child(5) {
  width: 50px;
  height: 50px;
  top: 70%;
  left: 60%;
  border-radius: 50%;
  animation-duration: 14s;
  animation-delay: -10s;
}

@keyframes shapeFloat {
  0%, 100% {
    transform: translateY(0) rotate(0deg);
    opacity: 0.4;
  }
  50% {
    transform: translateY(-30px) rotate(5deg);
    opacity: 0.7;
  }
}

/* Grid pattern overlay */
.hero-grid {
  position: absolute;
  inset: 0;
  z-index: 0;
  background-image:
    linear-gradient(var(--border-default) 1px, transparent 1px),
    linear-gradient(90deg, var(--border-default) 1px, transparent 1px);
  background-size: 60px 60px;
  opacity: 0.3;
  mask-image: radial-gradient(ellipse at center, black 20%, transparent 70%);
  -webkit-mask-image: radial-gradient(ellipse at center, black 20%, transparent 70%);
}

/* Hero content */
.hero-content {
  position: relative;
  z-index: 1;
  max-width: 800px;
  padding-inline: var(--space-xl);
}

.hero-tagline {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--accent-secondary);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: var(--space-lg);
  opacity: 0.9;
}

.hero-title {
  font-size: clamp(2.5rem, 8vw, 4.5rem);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: var(--space-xl);
  background: var(--gradient-text);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: clamp(1.1rem, 2.5vw, 1.35rem);
  color: var(--text-secondary);
  line-height: 1.7;
  max-width: 600px;
  margin-inline: auto;
  margin-bottom: var(--space-2xl);
}

.hero-cta {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-2xl);
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--bg-primary);
  background: var(--gradient-gold);
  border-radius: var(--border-radius-full);
  transition: transform var(--transition-spring),
              box-shadow var(--transition-normal);
  box-shadow: 0 4px 20px var(--accent-glow);
}

.hero-cta:hover {
  transform: translateY(-2px) scale(1.02);
  box-shadow: 0 8px 40px var(--accent-glow),
              0 0 60px rgba(212, 168, 83, 0.15);
}

/* Scroll indicator */
.hero-scroll {
  position: absolute;
  bottom: var(--space-2xl);
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
  color: var(--text-tertiary);
  font-size: 0.7rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  animation: scrollBounce 2s ease-in-out infinite;
}

.hero-scroll-line {
  width: 1px;
  height: 40px;
  background: linear-gradient(to bottom, var(--accent-primary), transparent);
}

@keyframes scrollBounce {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(8px); }
}

/* ============================================================
   7. STATS BAR - Key Metrics with Animated Counters
   ============================================================ */
.stats-bar {
  padding: var(--space-3xl) 0;
  position: relative;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--space-xl);
  max-width: var(--content-max-width);
  margin-inline: auto;
  padding-inline: var(--space-xl);
}

.stat-item {
  text-align: center;
  padding: var(--space-2xl) var(--space-lg);
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--border-radius-lg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  box-shadow: var(--glass-shadow);
  transition: transform var(--transition-spring),
              border-color var(--transition-normal),
              box-shadow var(--transition-normal);
}

.stat-item:hover {
  transform: translateY(-4px);
  border-color: var(--border-glow);
  box-shadow: var(--glass-shadow),
              0 0 30px var(--accent-glow);
}

.stat-number {
  font-size: 2.2rem;
  font-weight: 800;
  background: var(--gradient-gold);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: var(--space-sm);
}

.stat-label {
  font-size: 0.9rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.stat-sublabel {
  font-size: 0.75rem;
  color: var(--text-tertiary);
  margin-top: var(--space-xs);
  font-family: var(--font-mono);
}

/* Counter animation class */
.stat-number[data-animate] {
  animation: countReveal 1.5s ease-out forwards;
}

@keyframes countReveal {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ============================================================
   8. SECTION SHARED STYLES
   ============================================================ */
.section {
  padding: var(--space-3xl) 0;
  position: relative;
}

.section-header {
  margin-bottom: var(--space-2xl);
  max-width: var(--content-max-width);
  margin-inline: auto;
  padding-inline: var(--space-xl);
}

.section-title {
  font-size: clamp(1.8rem, 4vw, 2.5rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-md);
}

.section-title.gradient {
  background: var(--gradient-text);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 600px;
  line-height: 1.7;
}

/* ============================================================
   9. PROJECTS SECTION - 2-Column Glass Grid
   ============================================================ */
.projects-section {
  padding: var(--space-3xl) 0;
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-xl);
  max-width: var(--content-max-width);
  margin-inline: auto;
  padding-inline: var(--space-xl);
}

.project-card {
  position: relative;
  border-radius: var(--border-radius-lg);
  overflow: hidden;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  box-shadow: var(--glass-shadow);
  transition: transform var(--transition-spring),
              border-color var(--transition-normal),
              box-shadow var(--transition-normal);
  cursor: pointer;
}

.project-card:hover {
  transform: translateY(-6px) scale(1.01);
  border-color: var(--border-glow);
  box-shadow: var(--glass-shadow),
              0 20px 60px rgba(0, 0, 0, 0.3),
              0 0 40px var(--accent-glow);
}

/* Cover image area */
.project-card-cover {
  position: relative;
  width: 100%;
  height: 200px;
  overflow: hidden;
}

.project-card-cover img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-slow);
}

.project-card:hover .project-card-cover img {
  transform: scale(1.05);
}

/* Glass overlay gradient on cover */
.project-card-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to bottom, transparent 30%, var(--bg-primary) 100%);
  opacity: 0.85;
  pointer-events: none;
}

/* Card body */
.project-card-body {
  padding: var(--space-xl);
  position: relative;
}

.project-card-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--accent-secondary);
  background: rgba(34, 211, 238, 0.1);
  border: 1px solid rgba(34, 211, 238, 0.2);
  padding: 3px 10px;
  border-radius: var(--border-radius-full);
  margin-bottom: var(--space-md);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.project-card-tag.gold {
  color: var(--accent-primary);
  background: rgba(212, 168, 83, 0.1);
  border-color: rgba(212, 168, 83, 0.2);
}

.project-card-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: var(--space-sm);
  letter-spacing: -0.01em;
}

.project-card-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: var(--space-lg);
}

/* Metrics row at bottom of card */
.project-card-metrics {
  display: flex;
  gap: var(--space-lg);
  padding-top: var(--space-md);
  border-top: 1px solid var(--border-default);
}

.project-metric {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.project-metric-value {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--accent-primary);
}

.project-metric-label {
  font-size: 0.7rem;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

/* Featured card spans full width */
.project-card.featured {
  grid-column: 1 / -1;
  display: grid;
  grid-template-columns: 1fr 1fr;
}

.project-card.featured .project-card-cover {
  height: 100%;
  min-height: 280px;
}

.project-card.featured .project-card-body {
  display: flex;
  flex-direction: column;
  justify-content: center;
}

/* ============================================================
   10. TIMELINE / JOURNEY SECTION
   ============================================================ */
.journey-section {
  padding: var(--space-3xl) 0;
}

.timeline {
  position: relative;
  padding-left: 50px;
  max-width: var(--content-max-width);
  margin-inline: auto;
  padding-right: var(--space-xl);
}

/* Vertical line */
.timeline::before {
  content: '';
  position: absolute;
  left: 18px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(
    to bottom,
    transparent,
    var(--accent-primary-dim) 10%,
    var(--accent-secondary-dim) 50%,
    var(--accent-primary-dim) 90%,
    transparent
  );
  border-radius: 1px;
}

.timeline-item {
  position: relative;
  margin-bottom: var(--space-2xl);
}

.timeline-item:last-child {
  margin-bottom: 0;
}

/* Timeline node dot */
.timeline-node {
  position: absolute;
  left: -39px;
  top: 8px;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--bg-primary);
  border: 3px solid var(--accent-primary);
  box-shadow: 0 0 14px var(--accent-glow);
  transition: transform var(--transition-spring),
              box-shadow var(--transition-normal);
}

.timeline-item:hover .timeline-node {
  transform: scale(1.3);
  box-shadow: 0 0 24px var(--accent-glow),
              0 0 40px rgba(212, 168, 83, 0.15);
}

.timeline-node.cyan {
  border-color: var(--accent-secondary);
  box-shadow: 0 0 14px var(--accent-secondary-glow);
}

.timeline-item:hover .timeline-node.cyan {
  box-shadow: 0 0 24px var(--accent-secondary-glow),
              0 0 40px rgba(34, 211, 238, 0.15);
}

/* Timeline card */
.timeline-card {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--border-radius-md);
  padding: var(--space-xl);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  box-shadow: var(--glass-shadow);
  transition: transform var(--transition-spring),
              border-color var(--transition-normal),
              box-shadow var(--transition-normal);
}

.timeline-card:hover {
  transform: translateX(6px);
  border-color: var(--border-glow);
  box-shadow: var(--glass-shadow),
              0 10px 40px rgba(0, 0, 0, 0.3),
              0 0 20px var(--accent-glow);
}

.timeline-date {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--accent-primary);
  font-family: var(--font-mono);
  margin-bottom: var(--space-xs);
}

.timeline-title {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: var(--space-sm);
  letter-spacing: -0.01em;
}

.timeline-desc {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.7;
}

/* Horizontal timeline variant */
.timeline-horizontal {
  display: flex;
  gap: var(--space-lg);
  overflow-x: auto;
  padding: var(--space-xl) var(--space-xl);
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
  max-width: var(--content-max-width);
  margin-inline: auto;
}

.timeline-horizontal .timeline-item {
  flex: 0 0 280px;
  scroll-snap-align: start;
  margin-bottom: 0;
  padding-top: 30px;
}

.timeline-horizontal .timeline-node {
  left: 50%;
  top: 0;
  transform: translateX(-50%);
}

.timeline-horizontal .timeline-item:hover .timeline-node {
  transform: translateX(-50%) scale(1.3);
}

/* ============================================================
   11. SKILLS SECTION - Progress Bars and Tags
   ============================================================ */
.skills-section {
  padding: var(--space-3xl) 0;
}

.skills-content {
  max-width: var(--content-max-width);
  margin-inline: auto;
  padding-inline: var(--space-xl);
}

/* Skill progress bars */
.skill-bars {
  display: grid;
  gap: var(--space-lg);
  margin-bottom: var(--space-2xl);
}

.skill-bar-item {
  padding: var(--space-md) 0;
}

.skill-bar-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-sm);
}

.skill-bar-name {
  font-size: 0.9rem;
  font-weight: 600;
}

.skill-bar-value {
  font-size: 0.8rem;
  font-family: var(--font-mono);
  color: var(--accent-primary);
}

.skill-bar-track {
  height: 6px;
  border-radius: var(--border-radius-full);
  background: var(--bg-tertiary);
  overflow: hidden;
  position: relative;
}

.skill-bar-fill {
  height: 100%;
  border-radius: var(--border-radius-full);
  background: var(--gradient-text);
  width: 0;
  transition: width 1.5s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  position: relative;
}

/* Glowing dot at the end of progress bar */
.skill-bar-fill::after {
  content: '';
  position: absolute;
  right: -1px;
  top: 50%;
  transform: translateY(-50%);
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--accent-primary);
  box-shadow: 0 0 10px var(--accent-glow);
  opacity: 0;
  transition: opacity 0.3s ease 1.5s;
}

.skill-bar-fill.animated {
  width: var(--skill-level);
}

.skill-bar-fill.animated::after {
  opacity: 1;
}

/* Animated skill tags */
.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  padding: var(--space-lg) 0;
}

.skill-tag {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-sm) var(--space-md);
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--border-radius-full);
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all var(--transition-normal);
  cursor: default;
}

.skill-tag:hover {
  border-color: var(--accent-primary);
  color: var(--accent-primary);
  box-shadow: 0 0 15px var(--accent-glow);
  transform: translateY(-2px);
}

.skill-tag .tag-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent-primary);
}

.skill-tag.secondary .tag-dot {
  background: var(--accent-secondary);
}

.skill-tag.secondary:hover {
  border-color: var(--accent-secondary);
  color: var(--accent-secondary);
  box-shadow: 0 0 15px var(--accent-secondary-glow);
}

/* Pulsing animation for skill tags */
@keyframes tagPulse {
  0%, 100% { box-shadow: 0 0 0 0 var(--accent-glow); }
  50% { box-shadow: 0 0 12px 2px var(--accent-glow); }
}

.skill-tag.pulse {
  animation: tagPulse 3s ease-in-out infinite;
}

.skill-tag.pulse:nth-child(2n) {
  animation-delay: 0.5s;
}

.skill-tag.pulse:nth-child(3n) {
  animation-delay: 1s;
}

/* Radar chart container */
.skill-radar {
  display: flex;
  justify-content: center;
  padding: var(--space-2xl) 0;
}

.skill-radar svg {
  max-width: 400px;
  width: 100%;
}

/* ============================================================
   12. ABOUT SECTION
   ============================================================ */
.about-section {
  padding: var(--space-3xl) 0;
}

.about-content {
  max-width: var(--content-max-width);
  margin-inline: auto;
  padding-inline: var(--space-xl);
}

.about-intro {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: var(--space-2xl);
  align-items: center;
  margin-bottom: var(--space-3xl);
}

.about-photo {
  width: 100%;
  aspect-ratio: 1;
  border-radius: var(--border-radius-lg);
  object-fit: cover;
  border: 2px solid var(--glass-border);
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3),
              0 0 40px var(--accent-glow);
  transition: box-shadow var(--transition-normal);
}

.about-photo:hover {
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.4),
              0 0 60px var(--accent-glow);
}

.about-text {
  font-size: 1.05rem;
  line-height: 1.8;
  color: var(--text-secondary);
}

.about-highlight {
  color: var(--accent-primary);
  font-weight: 600;
}

.about-highlight.cyan {
  color: var(--accent-secondary);
}

/* ============================================================
   13. GLASS CARD - Reusable Component
   ============================================================ */
.glass-card {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--border-radius-md);
  padding: var(--space-xl);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  box-shadow: var(--glass-shadow);
  transition: transform var(--transition-spring),
              border-color var(--transition-normal),
              box-shadow var(--transition-normal);
}

.glass-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-glow);
  box-shadow: var(--glass-shadow),
              0 20px 60px rgba(0, 0, 0, 0.3),
              0 0 30px var(--accent-glow);
}

/* ============================================================
   14. FOOTER - Minimal Dark
   ============================================================ */
.footer {
  padding: var(--space-2xl) 0;
  border-top: 1px solid var(--border-default);
}

.footer-inner {
  max-width: var(--content-max-width);
  margin-inline: auto;
  padding-inline: var(--space-xl);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.footer-text {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.footer-links {
  display: flex;
  gap: var(--space-md);
}

.footer-links a {
  color: var(--text-muted);
  font-size: 0.85rem;
  transition: color var(--transition-fast);
}

.footer-links a:hover {
  color: var(--accent-primary);
}

/* ============================================================
   15. SCROLL ANIMATIONS
   ============================================================ */
@keyframes fadeSlideUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes scaleIn {
  from {
    opacity: 0;
    transform: scale(0.9);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

@keyframes slideInLeft {
  from {
    opacity: 0;
    transform: translateX(-40px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

/* Intersection Observer triggered classes */
.animate-on-scroll {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.animate-on-scroll.visible {
  opacity: 1;
  transform: translateY(0);
}

.animate-scale {
  opacity: 0;
  transform: scale(0.92);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.animate-scale.visible {
  opacity: 1;
  transform: scale(1);
}

.animate-slide-left {
  opacity: 0;
  transform: translateX(-40px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.animate-slide-left.visible {
  opacity: 1;
  transform: translateX(0);
}

.animate-slide-right {
  opacity: 0;
  transform: translateX(40px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.animate-slide-right.visible {
  opacity: 1;
  transform: translateX(0);
}

/* Stagger children */
.stagger-children > * {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.4s ease, transform 0.4s ease;
}

.stagger-children.visible > *:nth-child(1) { transition-delay: 0.05s; opacity: 1; transform: translateY(0); }
.stagger-children.visible > *:nth-child(2) { transition-delay: 0.1s; opacity: 1; transform: translateY(0); }
.stagger-children.visible > *:nth-child(3) { transition-delay: 0.15s; opacity: 1; transform: translateY(0); }
.stagger-children.visible > *:nth-child(4) { transition-delay: 0.2s; opacity: 1; transform: translateY(0); }
.stagger-children.visible > *:nth-child(5) { transition-delay: 0.25s; opacity: 1; transform: translateY(0); }
.stagger-children.visible > *:nth-child(6) { transition-delay: 0.3s; opacity: 1; transform: translateY(0); }
.stagger-children.visible > *:nth-child(7) { transition-delay: 0.35s; opacity: 1; transform: translateY(0); }
.stagger-children.visible > *:nth-child(8) { transition-delay: 0.4s; opacity: 1; transform: translateY(0); }

/* ============================================================
   16. RESPONSIVE DESIGN
   ============================================================ */

/* Tablet */
@media (max-width: 1024px) {
  .projects-grid {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }

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

  .project-card.featured .project-card-cover {
    min-height: 200px;
  }

  .about-intro {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .about-photo {
    max-width: 280px;
    margin: 0 auto;
  }
}

/* Mobile */
@media (max-width: 768px) {
  :root {
    --space-3xl: 3.5rem;
    --space-2xl: 2rem;
    --space-xl: 1.5rem;
  }

  .nav-links {
    display: none;
  }

  .nav-mobile-toggle {
    display: block;
  }

  .hero-title {
    font-size: clamp(2rem, 10vw, 3rem);
  }

  .hero-subtitle {
    font-size: 1rem;
  }

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

  .timeline {
    padding-left: 40px;
  }

  .timeline::before {
    left: 12px;
  }

  .timeline-node {
    left: -34px;
    width: 14px;
    height: 14px;
  }

  .timeline-horizontal {
    flex-direction: column;
    overflow-x: visible;
  }

  .timeline-horizontal .timeline-item {
    flex: none;
    width: 100%;
  }

  .footer-inner {
    flex-direction: column;
    gap: var(--space-md);
    text-align: center;
  }

  .section-title {
    font-size: 1.6rem;
  }
}

/* Small mobile */
@media (max-width: 480px) {
  :root {
    --space-xl: 1rem;
  }

  body {
    font-size: 0.9rem;
  }

  .hero {
    padding-left: var(--space-md);
    padding-right: var(--space-md);
  }

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

  .project-card-body {
    padding: var(--space-lg);
  }

  .project-card-metrics {
    flex-direction: column;
    gap: var(--space-sm);
  }

  .skill-tags {
    gap: var(--space-xs);
  }

  .skill-tag {
    font-size: 0.75rem;
    padding: var(--space-xs) var(--space-sm);
  }

  .timeline-card {
    padding: var(--space-lg);
  }
}

/* ============================================================
   17. ACCESSIBILITY AND MOTION PREFERENCES
   ============================================================ */

/* Reduce motion for users who prefer it */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .hero-mesh,
  .hero-shape {
    animation: none;
  }

  .animate-on-scroll,
  .animate-scale,
  .animate-slide-left,
  .animate-slide-right {
    opacity: 1;
    transform: none;
  }

  .stagger-children > * {
    opacity: 1;
    transform: none;
  }
}

/* Focus visible styles */
:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 3px;
  border-radius: var(--border-radius-sm);
}

/* Text selection */
::selection {
  background: rgba(212, 168, 83, 0.3);
  color: var(--text-primary);
}

/* Custom scrollbar - Webkit */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
  background: var(--bg-surface);
  border-radius: var(--border-radius-full);
}

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

/* Firefox scrollbar */
html {
  scrollbar-width: thin;
  scrollbar-color: var(--bg-surface) var(--bg-primary);
}

/* ============================================================
   18. PRINT STYLES
   ============================================================ */
@media print {
  body {
    background: white;
    color: black;
  }

  .nav,
  .hero-shapes,
  .hero-mesh,
  .hero-grid,
  .hero-scroll,
  .theme-toggle {
    display: none;
  }

  .glass-card,
  .project-card,
  .timeline-card,
  .stat-item {
    border: 1px solid #ccc;
    background: white;
    box-shadow: none;
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
  }

  .text-gradient,
  .hero-title,
  .nav-logo,
  .stat-number,
  .section-title.gradient {
    -webkit-text-fill-color: initial;
    background: none;
    color: black;
  }
}