/* MODERN PROFESSIONAL DESIGN SYSTEM - PORTFOLIO 2025 */

:root {
  /* Primary Brand Colors - Modern Blue Palette */
  --primary-color: #0f1419;
  --primary-dark: #000000;
  --primary-light: #1e293b;
  --secondary-color: #64748b;
  --accent-color: #3b82f6;
  --accent-dark: #2563eb;
  --accent-light: #60a5fa;

  /* Status Colors - Professional Palette */
  --success-color: #10b981;
  --warning-color: #f59e0b;
  --error-color: #ef4444;
  --info-color: #06b6d4;

  /* Text Colors - Enhanced Readability */
  --text-primary: #0f1419;
  --text-secondary: #374151;
  --text-muted: #6b7280;
  --text-light: #9ca3af;
  --text-white: #ffffff;
  --text-inverse: #f9fafb;

  /* Background Colors - Clean & Modern */
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-muted: #f1f5f9;
  --bg-dark: #0f1419;
  --bg-darker: #000000;
  --bg-accent: #f0f9ff;

  /* Gradient Backgrounds - Subtle & Professional */
  --bg-gradient: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 50%, #cbd5e1 100%);
  --bg-gradient-hero: linear-gradient(135deg, #0f1419 0%, #1e293b 50%, #374151 100%);
  --bg-gradient-card: linear-gradient(135deg, #ffffff 0%, #f8fafc 100%);

  /* Border & Surface */
  --border-color: #e5e7eb;
  --border-light: #f3f4f6;
  --border-dark: #d1d5db;
  --border-radius: 12px;
  --border-radius-lg: 16px;
  --border-radius-xl: 20px;
  --border-radius-full: 9999px;

  /* Shadows - Modern & Subtle */
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
  --shadow-2xl: 0 25px 50px -12px rgb(0 0 0 / 0.25);
  --shadow-inner: inset 0 2px 4px 0 rgb(0 0 0 / 0.05);

  /* Transitions - Smooth & Modern */
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-fast: all 0.15s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-bounce: all 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);

  /* Typography - Modern & Readable */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', monospace;

  /* Spacing - Consistent Scale */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;

  /* Z-Index Scale */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;
  --z-toast: 1080;
}

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

body {
  font-family: var(--font-family);
  font-size: 16px;
  line-height: 1.6;
  font-weight: 400;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  -webkit-text-size-adjust: 100%;
}

/* MODERN TYPOGRAPHY SYSTEM */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: 1.2;
  margin-bottom: var(--space-lg);
  letter-spacing: -0.025em;
  color: var(--text-primary);
}

h1 {
  font-size: clamp(2.5rem, 5vw, 4rem);
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 1.1;
}

h2 {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.15;
}

h3 {
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

h4 {
  font-size: clamp(1.25rem, 2.5vw, 1.5rem);
  font-weight: 600;
  line-height: 1.25;
}

p {
  margin-bottom: var(--space-lg);
  color: var(--text-secondary);
  line-height: 1.7;
  font-size: 1rem;
}

.section-description {
  font-size: 1.125rem;
  color: var(--text-muted);
  max-width: 600px;
  margin: 0 auto var(--space-3xl);
  line-height: 1.6;
  font-weight: 400;
}

/* MODERN NAVIGATION */
.main-navigation {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-color);
  z-index: var(--z-fixed);
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-xl);
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
  text-decoration: none;
  transition: var(--transition);
  letter-spacing: -0.02em;
}

.logo-image {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  object-fit: cover;
}

.nav-logo:hover {
  color: var(--accent-color);
  transform: scale(1.02);
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: var(--space-xl);
  align-items: center;
}

.nav-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.95rem;
  transition: var(--transition-fast);
  position: relative;
  padding: var(--space-sm) 0;
  letter-spacing: 0.01em;
}

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

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--accent-color), var(--accent-light));
  transition: var(--transition);
  border-radius: var(--border-radius-full);
}

.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}

.cta-button {
  background: linear-gradient(135deg, var(--accent-color), var(--accent-dark));
  color: var(--text-white);
  padding: var(--space-md) var(--space-xl);
  border-radius: var(--border-radius-full);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  transition: var(--transition-fast);
  box-shadow: var(--shadow-sm);
  border: 2px solid transparent;
  letter-spacing: 0.01em;
  position: relative;
  overflow: hidden;
}

.cta-button::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
  transition: left var(--transition);
}

.cta-button:hover::before {
  left: 100%;
}

.cta-button:hover {
  background: linear-gradient(135deg, var(--accent-dark), var(--accent-color));
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

/* MOBILE MENU TOGGLE */
.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.mobile-menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: space-around;
  width: 30px;
  height: 30px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 0;
  z-index: 10;
}

.hamburger-line {
  width: 100%;
  height: 3px;
  background-color: var(--text-primary);
  border-radius: 2px;
  transition: var(--transition-fast);
  transform-origin: center;
}

.mobile-menu-toggle.active .hamburger-line:nth-child(1) {
  transform: rotate(45deg) translate(6px, 6px);
}

.mobile-menu-toggle.active .hamburger-line:nth-child(2) {
  opacity: 0;
}

.mobile-menu-toggle.active .hamburger-line:nth-child(3) {
  transform: rotate(-45deg) translate(6px, -6px);
}

/* MODERN HERO SECTION */
.hero-section {
  padding: 140px 0 100px;
  background: var(--bg-gradient-hero);
  color: var(--text-white);
  min-height: 100vh;
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
}

.hero-section::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="25" cy="25" r="1" fill="white" opacity="0.03"/><circle cx="75" cy="75" r="1" fill="white" opacity="0.03"/><circle cx="50" cy="10" r="0.5" fill="white" opacity="0.02"/><circle cx="10" cy="50" r="0.5" fill="white" opacity="0.02"/><circle cx="90" cy="30" r="0.5" fill="white" opacity="0.02"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
  pointer-events: none;
}

.hero-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-xl);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6rem;
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  background: rgba(255, 255, 255, 0.15);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--border-radius-xl);
  padding: var(--space-sm) var(--space-lg);
  margin-bottom: var(--space-xl);
  font-size: 0.875rem;
  font-weight: 500;
  letter-spacing: 0.025em;
}

.hero-title {
  font-size: clamp(2.5rem, 5vw, 4rem);
  font-weight: 700;
  margin-bottom: var(--space-lg);
  line-height: 1.1;
  letter-spacing: -0.04em;
  color: var(--text-white);
}

.hero-subtitle {
  font-size: 1.25rem;
  color: rgba(255, 255, 255, 0.9);
  margin-bottom: var(--space-3xl);
  line-height: 1.6;
  font-weight: 400;
}

.hero-actions {
  display: flex;
  gap: var(--space-lg);
  flex-wrap: wrap;
  margin-bottom: var(--space-3xl);
}

.btn-primary, .btn-secondary {
  padding: var(--space-lg) var(--space-2xl);
  border-radius: var(--border-radius-xl);
  text-decoration: none;
  font-weight: 600;
  font-size: 1rem;
  transition: var(--transition);
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  position: relative;
  overflow: hidden;
}

.btn-primary {
  background: var(--text-white);
  color: var(--text-primary);
  box-shadow: var(--shadow-xl);
  border: 2px solid var(--text-white);
}

.btn-primary::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(59, 130, 246, 0.1), transparent);
  transition: var(--transition);
}

.btn-primary:hover::before {
  left: 100%;
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-2xl);
  background: rgba(255, 255, 255, 0.95);
}

.btn-secondary {
  background: transparent;
  color: var(--text-white);
  border: 2px solid rgba(255, 255, 255, 0.3);
  backdrop-filter: blur(10px);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.5);
  transform: translateY(-2px);
}

.btn-tertiary {
  background: transparent;
  color: var(--text-white);
  border: 2px solid var(--accent-color);
  padding: var(--space-md) var(--space-xl);
  border-radius: var(--border-radius-full);
  font-weight: 600;
  text-decoration: none;
  transition: all 0.3s ease;
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  backdrop-filter: blur(10px);
  position: relative;
  overflow: hidden;
}

.btn-tertiary:hover {
  background: var(--accent-color);
  color: var(--text-white);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
  margin-top: var(--space-3xl);
}

.stat-item {
  text-align: center;
  padding: var(--space-lg);
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  border-radius: var(--border-radius-lg);
  border: 1px solid rgba(255, 255, 255, 0.2);
}

.stat-number {
  font-size: 2rem;
  font-weight: 700;
  display: block;
  margin-bottom: var(--space-sm);
  color: var(--text-white);
}

.stat-label {
  font-size: 0.875rem;
  color: rgba(255, 255, 255, 0.8);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.025em;
}

.hero-visual {
  position: relative;
}

/* NEURAL NETWORK VISUALIZATION */
.neural-network-container {
  position: relative;
  width: 100%;
  max-width: 500px;
  height: 400px;
  margin: 0 auto;
}

.neural-canvas {
  width: 100%;
  height: 100%;
  border-radius: var(--border-radius-lg);
  background: rgba(15, 20, 25, 0.02);
  backdrop-filter: blur(20px);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.neural-overlay {
  position: absolute;
  bottom: 20px;
  left: 20px;
  right: 20px;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(20px);
  border-radius: var(--border-radius);
  padding: var(--space-lg);
  border: 1px solid rgba(255, 255, 255, 0.2);
}

.data-metrics {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-md);
  text-align: center;
}

.metric-item {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.metric-value {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent-color);
  margin-bottom: var(--space-xs);
}

.metric-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: 500;
}

.hero-illustration {
  filter: drop-shadow(0 20px 40px rgba(0, 0, 0, 0.1));
}

.hero-illustration svg {
  width: 100%;
  height: auto;
  max-width: 400px;
}

/* MODERN CONTENT SECTIONS */
.content-section {
  padding: var(--space-4xl) 0;
  background: var(--bg-secondary);
}

.content-section:nth-child(even) {
  background: var(--bg-primary);
}

.section-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

.section-header {
  text-align: center;
  margin-bottom: var(--space-4xl);
}

.section-header h2 {
  color: var(--text-primary);
  margin-bottom: var(--space-lg);
}

/* ABOUT SECTION */
.about-grid {
  max-width: 800px;
  margin: 0 auto;
}

.about-content p {
  font-size: 1.125rem;
  line-height: 1.7;
  margin-bottom: var(--space-xl);
}

.about-highlights {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-xl);
  margin-top: var(--space-3xl);
}

.highlight-item {
  background: var(--bg-primary);
  padding: var(--space-xl);
  border-radius: var(--border-radius-lg);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
}

.highlight-item h4 {
  margin-bottom: var(--space-md);
  font-size: 1.125rem;
}

.highlight-item p {
  margin: 0;
  font-size: 0.95rem;
  color: var(--text-muted);
}

/* EXPERTISE SECTION */
.expertise-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-xl);
}

/* ENHANCED VISUAL EFFECTS */
.expertise-card {
  background: var(--bg-primary);
  padding: var(--space-2xl);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow);
  transition: all var(--transition);
  cursor: pointer;
  border: 1px solid var(--border-color);
  position: relative;
  overflow: hidden;
}

.expertise-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--accent-color), var(--accent-light));
  transform: scaleX(0);
  transition: var(--transition);
  transform-origin: left;
}

.expertise-card::after {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(59, 130, 246, 0.03), transparent);
  transition: var(--transition-slow);
}

.expertise-card:hover::before {
  transform: scaleX(1);
}

.expertise-card:hover::after {
  left: 100%;
}

.expertise-card:hover {
  transform: translateY(-6px) scale(1.02);
  box-shadow: 0 20px 40px -12px rgba(59, 130, 246, 0.15);
  border-color: var(--accent-color);
}

.card-icon {
  font-size: 2.5rem;
  margin-bottom: var(--space-lg);
  display: block;
  color: var(--accent-color);
  transition: var(--transition);
}

.expertise-card:hover .card-icon {
  transform: scale(1.1) rotate(5deg);
  color: var(--accent-dark);
}

.expertise-card h3 {
  color: var(--text-primary);
  margin-bottom: var(--space-md);
  font-size: 1.25rem;
  font-weight: 600;
  transition: var(--transition);
}

.expertise-card:hover h3 {
  color: var(--accent-color);
}

.expertise-card p {
  color: var(--text-secondary);
  margin-bottom: var(--space-lg);
  line-height: 1.6;
  transition: var(--transition);
}

.expertise-card:hover p {
  color: var(--text-primary);
}

.tech-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.tag {
  background: var(--bg-secondary);
  color: var(--text-secondary);
  padding: var(--space-xs) var(--space-md);
  border-radius: 20px;
  font-size: 0.875rem;
  font-weight: 500;
  border: 1px solid var(--border-color);
  transition: var(--transition);
}

.expertise-card:hover .tag {
  background: rgba(59, 130, 246, 0.1);
  border-color: var(--accent-color);
  color: var(--accent-color);
  transform: translateY(-2px);
}

/* PROJECTS SECTION - Enhanced */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: var(--space-xl);
}

.project-card {
  background: var(--bg-primary);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow);
  transition: all var(--transition);
  border: 1px solid var(--border-color);
  overflow: hidden;
  position: relative;
  cursor: pointer;
}

.project-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(59, 130, 246, 0.03), transparent);
  transition: var(--transition-slow);
}

.project-card:hover::before {
  left: 100%;
}

.project-card:hover {
  transform: translateY(-8px) scale(1.02);
  box-shadow: 0 25px 50px -12px rgba(59, 130, 246, 0.15);
  border-color: var(--accent-color);
}

.project-header {
  padding: var(--space-xl) var(--space-xl) var(--space-lg);
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: var(--space-md);
  position: relative;
}

.project-header::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: var(--space-xl);
  right: var(--space-xl);
  height: 1px;
  background: linear-gradient(90deg, var(--accent-color), transparent);
  opacity: 0;
  transition: var(--transition);
}

.project-card:hover .project-header::after {
  opacity: 1;
}

.project-header h3 {
  margin: 0;
  font-size: 1.25rem;
  color: var(--text-primary);
  font-weight: 600;
  transition: var(--transition);
}

.project-card:hover .project-header h3 {
  color: var(--accent-color);
}

.project-status {
  background: var(--success-color);
  color: white;
  padding: var(--space-xs) var(--space-md);
  border-radius: var(--border-radius-full);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.025em;
  white-space: nowrap;
  box-shadow: 0 4px 12px rgba(16, 185, 129, 0.25);
  transition: var(--transition);
}

.project-card:hover .project-status {
  transform: scale(1.05);
  box-shadow: 0 6px 16px rgba(16, 185, 129, 0.35);
}

.project-card p {
  padding: 0 var(--space-xl);
  margin-bottom: var(--space-lg);
  color: var(--text-secondary);
  line-height: 1.6;
  transition: var(--transition);
}

.project-card:hover p {
  color: var(--text-primary);
}

.project-tags {
  padding: 0 var(--space-xl);
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-xl);
}

.project-actions {
  padding: 0 var(--space-xl) var(--space-xl);
}

.project-actions .btn-primary,
.project-actions .btn-secondary {
  padding: var(--space-md) var(--space-lg);
  font-size: 0.875rem;
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}

.project-actions .btn-secondary {
  background: transparent;
  border: 2px solid var(--border-color);
  color: var(--text-secondary);
}

.project-card:hover .project-actions .btn-secondary {
  border-color: var(--accent-color);
  color: var(--accent-color);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

/* EXPERIENCE SECTION */
.timeline {
  max-width: 800px;
  margin: 0 auto;
  position: relative;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 30px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--border-color);
}

.timeline-item {
  position: relative;
  margin-bottom: var(--space-3xl);
  padding-left: 80px;
}

.timeline-marker {
  position: absolute;
  left: 20px;
  top: 0;
  width: 20px;
  height: 20px;
  background: var(--accent-color);
  border-radius: 50%;
  border: 4px solid var(--bg-primary);
  box-shadow: 0 0 0 4px var(--border-color);
}

.timeline-content {
  background: var(--bg-primary);
  padding: var(--space-xl);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-color);
}

.timeline-content h3 {
  margin-bottom: var(--space-sm);
  color: var(--text-primary);
  font-size: 1.25rem;
}

.timeline-content h4 {
  margin-bottom: var(--space-sm);
  color: var(--text-secondary);
  font-size: 1rem;
  font-weight: 500;
}

.timeline-date {
  color: var(--accent-color);
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: var(--space-md);
  display: block;
}

.timeline-content p {
  margin: 0;
  color: var(--text-secondary);
}

/* CONTACT SECTION */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4xl);
  align-items: start;
}

.contact-info {
  display: flex;
  flex-direction: column;
  gap: var(--space-xl);
}

.contact-item {
  display: flex;
  align-items: flex-start;
  gap: var(--space-lg);
  padding: var(--space-lg);
  background: var(--bg-primary);
  border-radius: var(--border-radius-lg);
  border: 1px solid var(--border-color);
}

.contact-icon {
  color: var(--accent-color);
  font-size: 1.25rem;
  margin-top: var(--space-xs);
}

.contact-item h4 {
  margin-bottom: var(--space-sm);
  color: var(--text-primary);
  font-size: 1rem;
}

.contact-item p {
  margin: 0;
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.contact-form {
  background: var(--bg-primary);
  padding: var(--space-2xl);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow);
  border: 1px solid var(--border-color);
}

.form-group {
  margin-bottom: var(--space-xl);
}

.form-group label {
  display: block;
  margin-bottom: var(--space-sm);
  color: var(--text-primary);
  font-weight: 500;
  font-size: 0.95rem;
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: var(--space-md);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  font-family: var(--font-family);
  font-size: 1rem;
  background: var(--bg-primary);
  color: var(--text-primary);
  transition: var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--accent-color);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.form-group textarea {
  resize: vertical;
  min-height: 120px;
}

.contact-form .btn-primary {
  background: var(--accent-color);
  color: var(--text-white);
  border: none;
  padding: var(--space-lg) var(--space-2xl);
  border-radius: var(--border-radius);
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  font-size: 1rem;
}

.contact-form .btn-primary:hover {
  background: var(--accent-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

/* FOOTER */
.site-footer {
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--primary-light) 100%);
  color: var(--text-white);
  padding: var(--space-4xl) 0 var(--space-2xl);
  border-top: 1px solid var(--border-color);
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-xl);
  margin-bottom: var(--space-2xl);
}

.footer-section h4 {
  color: var(--text-white);
  margin-bottom: var(--space-lg);
  font-size: 1.125rem;
  font-weight: 600;
}

.footer-section p {
  color: rgba(255, 255, 255, 0.8);
  margin-bottom: var(--space-lg);
  line-height: 1.6;
}

.footer-section ul {
  list-style: none;
  padding: 0;
}

.footer-section ul li {
  margin-bottom: var(--space-sm);
}

.footer-section ul a {
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
  transition: var(--transition);
  font-size: 0.875rem;
}

.footer-section ul a:hover {
  color: var(--accent-light);
}

/* RESPONSIVE DESIGN */
@media (max-width: 768px) {
  .nav-container {
    padding: 0 var(--space-lg);
    height: 60px;
  }

  .mobile-menu-toggle {
    display: flex;
  }

  .cta-button {
    display: none;
  }

  .nav-menu {
    position: fixed;
    top: 60px;
    left: 0;
    right: 0;
    background: var(--bg-primary);
    border-top: 1px solid var(--border-color);
    box-shadow: var(--shadow-lg);
    flex-direction: column;
    padding: var(--space-lg);
    gap: var(--space-lg);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition);
    z-index: var(--z-dropdown);
  }

  .nav-menu.active {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav-menu li {
    width: 100%;
  }

  .nav-link {
    display: block;
    padding: var(--space-md);
    text-align: center;
    font-size: 1.1rem;
    border-bottom: 1px solid var(--border-light);
  }

  .nav-link:last-child {
    border-bottom: none;
  }

  .neural-network-container {
    height: 300px;
    margin: var(--space-xl) 0;
  }
  
  .data-metrics {
    grid-template-columns: 1fr;
    gap: var(--space-sm);
  }
  
  .metric-item {
    padding: var(--space-sm);
  }

  .hero-container {
    grid-template-columns: 1fr;
    gap: var(--space-2xl);
    text-align: center;
    padding: 0 var(--space-lg);
  }

  .hero-title {
    font-size: 2.5rem;
  }

  .hero-stats {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }

  .section-container {
    padding: 0 var(--space-lg);
  }

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

  .about-highlights {
    grid-template-columns: 1fr;
  }

  .contact-grid {
    grid-template-columns: 1fr;
    gap: var(--space-2xl);
  }

  .timeline::before {
    left: 15px;
  }

  .timeline-item {
    padding-left: 60px;
  }

  .timeline-marker {
    left: 5px;
    width: 20px;
    height: 20px;
  }

  .footer-content {
    grid-template-columns: 1fr;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .hero-section {
    padding: 100px 0 60px;
  }

  .hero-title {
    font-size: 2rem;
  }

  .hero-actions {
    flex-direction: column;
    align-items: center;
  }

  .btn-primary,
  .btn-secondary,
  .btn-tertiary {
    width: 100%;
    text-align: center;
  }

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

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

  .contact-form {
    padding: var(--space-lg);
  }
}

/* ACCESSIBILITY */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* FOCUS STYLES */
.nav-link:focus,
.cta-button:focus,
.btn-primary:focus,
.btn-secondary:focus,
.expertise-card:focus,
.project-card:focus {
  outline: 2px solid var(--accent-color);
  outline-offset: 2px;
}