/* ============================================
   PORTFOLIO STYLESHEET
   Author: Pavan Kalaganda
   Description: Modern, responsive portfolio with
   dark/light mode, animations, and accessibility
   ============================================ */

/* ------------------------------------------
   CSS Custom Properties (Design Tokens)
   ------------------------------------------ */
:root {
  /* Light Mode Colors */
  --color-bg: #fafafa;
  --color-bg-alt: #f0f0f0;
  --color-bg-card: #ffffff;
  --color-bg-code: #f5f5f5;
  --color-text: #1a1a2e;
  --color-text-secondary: #4a4a6a;
  --color-text-muted: #6b6b8a;
  --color-border: #e0e0e0;
  --color-border-hover: #c0c0c0;

  /* Primary Accent - Indigo */
  --color-primary: #4f46e5;
  --color-primary-light: #6366f1;
  --color-primary-dark: #4338ca;
  --color-primary-glow: rgba(79, 70, 229, 0.15);

  /* Secondary Accent - Teal */
  --color-secondary: #0d9488;
  --color-secondary-light: #14b8a6;

  /* Gradient */
  --gradient-primary: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
  --gradient-hero: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.1), 0 10px 10px -5px rgba(0,0,0,0.04);
  --shadow-glow: 0 0 20px var(--color-primary-glow);

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

  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
  --text-5xl: 3rem;
  --text-6xl: 3.75rem;

  --font-light: 300;
  --font-normal: 400;
  --font-medium: 500;
  --font-semibold: 600;
  --font-bold: 700;
  --font-extrabold: 800;

  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;

  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.5rem;
  --radius-full: 9999px;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 350ms ease;
  --transition-bounce: 500ms cubic-bezier(0.34, 1.56, 0.64, 1);

  /* Z-Index Scale */
  --z-base: 0;
  --z-dropdown: 100;
  --z-sticky: 200;
  --z-fixed: 300;
  --z-modal-backdrop: 400;
  --z-modal: 500;
  --z-popover: 600;
  --z-tooltip: 700;
}

/* Dark Mode Colors */
[data-theme="dark"] {
  --color-bg: #0f0f1a;
  --color-bg-alt: #1a1a2e;
  --color-bg-card: #16162a;
  --color-bg-code: #1e1e3f;
  --color-text: #e2e8f0;
  --color-text-secondary: #a0aec0;
  --color-text-muted: #718096;
  --color-border: #2d2d4a;
  --color-border-hover: #3d3d6a;

  --color-primary: #818cf8;
  --color-primary-light: #a5b4fc;
  --color-primary-dark: #6366f1;
  --color-primary-glow: rgba(129, 140, 248, 0.2);

  --color-secondary: #2dd4bf;
  --color-secondary-light: #5eead4;

  --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.4), 0 2px 4px -1px rgba(0,0,0,0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.4), 0 4px 6px -2px rgba(0,0,0,0.3);
  --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.5), 0 10px 10px -5px rgba(0,0,0,0.4);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  font-weight: var(--font-normal);
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  transition: background-color var(--transition-base), color var(--transition-base);
  overflow-x: hidden;
}

/* Skip Link for Accessibility */
.skip-link {
  position: absolute;
  top: -100%;
  left: 50%;
  transform: translateX(-50%);
  background: var(--color-primary);
  color: white;
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-md);
  font-weight: var(--font-semibold);
  z-index: var(--z-tooltip);
  text-decoration: none;
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: var(--space-4);
}

/* Selection */
::selection {
  background: var(--color-primary);
  color: white;
}

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

/* Scrollbar */
::-webkit-scrollbar {
  width: 8px;
}

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

::-webkit-scrollbar-thumb {
  background: var(--color-border-hover);
  border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-text-muted);
}

/* ------------------------------------------
   Typography
   ------------------------------------------ */
h1, h2, h3, h4, h5, h6 {
  font-weight: var(--font-bold);
  line-height: 1.2;
  color: var(--color-text);
}

h1 { font-size: var(--text-4xl); }
h2 { font-size: var(--text-3xl); }
h3 { font-size: var(--text-2xl); }
h4 { font-size: var(--text-xl); }

p {
  margin-bottom: var(--space-4);
  color: var(--color-text-secondary);
}

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

a:hover {
  color: var(--color-primary-dark);
}

strong {
  font-weight: var(--font-semibold);
  color: var(--color-text);
}

code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--color-bg-code);
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  color: var(--color-secondary);
}

/* ------------------------------------------
   Layout Utilities
   ------------------------------------------ */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-6);
}

@media (max-width: 768px) {
  .container {
    padding: 0 var(--space-4);
  }
}

.section {
  padding: var(--space-24) 0;
  position: relative;
}

@media (max-width: 768px) {
  .section {
    padding: var(--space-16) 0;
  }
}

/* ------------------------------------------
   Section Headers
   ------------------------------------------ */
.section-header {
  text-align: center;
  margin-bottom: var(--space-16);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.section-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-primary);
  background: var(--color-primary-glow);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-full);
  margin-bottom: var(--space-4);
  letter-spacing: 0.05em;
}

.section-title {
  font-size: var(--text-4xl);
  font-weight: var(--font-extrabold);
  margin-bottom: var(--space-4);
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

@media (max-width: 768px) {
  .section-title {
    font-size: var(--text-3xl);
  }
}

.section-subtitle {
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  margin-bottom: 0;
}

/* ------------------------------------------
   Buttons
   ------------------------------------------ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  font-family: var(--font-sans);
  font-size: var(--text-base);
  font-weight: var(--font-semibold);
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-lg);
  border: 2px solid transparent;
  cursor: pointer;
  transition: all var(--transition-base);
  text-decoration: none;
  line-height: 1.5;
}

.btn-primary {
  background: var(--gradient-primary);
  color: white;
  border-color: transparent;
  box-shadow: var(--shadow-md);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
  color: white;
}

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn-outline:hover {
  background: var(--color-primary);
  color: white;
  transform: translateY(-2px);
}

.btn-sm {
  font-size: var(--text-sm);
  padding: var(--space-2) var(--space-4);
}

.btn-lg {
  font-size: var(--text-lg);
  padding: var(--space-4) var(--space-8);
}

.btn-full {
  width: 100%;
}

/* ------------------------------------------
   Navigation
   ------------------------------------------ */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: var(--z-fixed);
  background: rgba(var(--color-bg), 0.8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  transition: all var(--transition-base);
}

.navbar.scrolled {
  box-shadow: var(--shadow-md);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-6);
  height: 70px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-family: var(--font-mono);
  font-size: var(--text-xl);
  font-weight: var(--font-bold);
  color: var(--color-text);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.logo-bracket {
  color: var(--color-primary);
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: var(--space-8);
  align-items: center;
}

.nav-link {
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-text-secondary);
  text-decoration: none;
  padding: var(--space-2) 0;
  position: relative;
  transition: color var(--transition-fast);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--gradient-primary);
  transition: width var(--transition-base);
}

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

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

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.theme-toggle {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
  background: var(--color-bg-card);
  color: var(--color-text);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.theme-toggle:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-glow);
}

.theme-toggle .fa-sun,
.theme-toggle .fa-moon {
  position: absolute;
  transition: all var(--transition-base);
}

[data-theme="light"] .theme-toggle .fa-sun {
  opacity: 0;
  transform: rotate(90deg) scale(0);
}

[data-theme="light"] .theme-toggle .fa-moon {
  opacity: 1;
  transform: rotate(0) scale(1);
}

[data-theme="dark"] .theme-toggle .fa-sun {
  opacity: 1;
  transform: rotate(0) scale(1);
}

[data-theme="dark"] .theme-toggle .fa-moon {
  opacity: 0;
  transform: rotate(-90deg) scale(0);
}

/* Mobile Toggle */
.mobile-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-2);
}

.hamburger-line {
  width: 24px;
  height: 2px;
  background: var(--color-text);
  border-radius: var(--radius-full);
  transition: all var(--transition-base);
}

@media (max-width: 768px) {
  .mobile-toggle {
    display: flex;
  }

  .nav-menu {
    position: fixed;
    top: 70px;
    left: 0;
    right: 0;
    background: var(--color-bg-card);
    flex-direction: column;
    padding: var(--space-6);
    gap: var(--space-4);
    border-bottom: 1px solid var(--color-border);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
    box-shadow: var(--shadow-lg);
  }

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

  .nav-actions {
    gap: var(--space-2);
  }

  .nav-actions .btn-sm {
    display: none;
  }
}

/* ------------------------------------------
   Hero Section
   ------------------------------------------ */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  padding-top: 70px;
  overflow: hidden;
}

.hero-background {
  position: absolute;
  inset: 0;
  z-index: 0;
}

#heroCanvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.hero-gradient-overlay {
  position: absolute;
  inset: 0;
  background: var(--gradient-hero);
  opacity: 0.95;
}

.hero-content {
  position: relative;
  z-index: 1;
  text-align: center;
  max-width: 800px;
  padding: var(--space-8);
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  background: rgba(255,255,255,0.1);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255,255,255,0.2);
  padding: var(--space-2) var(--space-5);
  border-radius: var(--radius-full);
  color: rgba(255,255,255,0.9);
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  margin-bottom: var(--space-6);
}

.hero-badge i {
  color: var(--color-secondary-light);
}

.hero-title {
  font-size: clamp(var(--text-4xl), 5vw, var(--text-6xl));
  font-weight: var(--font-extrabold);
  color: white;
  margin-bottom: var(--space-4);
  line-height: 1.1;
}

.text-gradient {
  background: linear-gradient(135deg, #a5b4fc 0%, #2dd4bf 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: clamp(var(--text-xl), 3vw, var(--text-2xl));
  font-weight: var(--font-medium);
  color: rgba(255,255,255,0.8);
  margin-bottom: var(--space-6);
  min-height: 2.5em;
}

.typing-cursor {
  color: var(--color-secondary-light);
  animation: blink 1s step-end infinite;
}

@keyframes blink {
  50% { opacity: 0; }
}

.hero-description {
  font-size: var(--text-lg);
  color: rgba(255,255,255,0.7);
  max-width: 600px;
  margin: 0 auto var(--space-8);
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  gap: var(--space-4);
  justify-content: center;
  margin-bottom: var(--space-12);
  flex-wrap: wrap;
}

.hero-actions .btn-primary {
  background: white;
  color: var(--color-primary-dark);
}

.hero-actions .btn-primary:hover {
  background: rgba(255,255,255,0.9);
  color: var(--color-primary-dark);
}

.hero-actions .btn-outline {
  border-color: rgba(255,255,255,0.5);
  color: white;
}

.hero-actions .btn-outline:hover {
  background: rgba(255,255,255,0.1);
  color: white;
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: var(--space-12);
  flex-wrap: wrap;
}

.stat-item {
  text-align: center;
}

.stat-number {
  display: block;
  font-size: var(--text-3xl);
  font-weight: var(--font-extrabold);
  color: white;
  line-height: 1;
}

.stat-label {
  font-size: var(--text-sm);
  color: rgba(255,255,255,0.6);
  margin-top: var(--space-2);
}

/* Scroll Indicator */
.scroll-indicator {
  position: absolute;
  bottom: var(--space-8);
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  color: rgba(255,255,255,0.5);
  font-size: var(--text-xs);
  animation: bounce 2s infinite;
}

.mouse {
  width: 24px;
  height: 36px;
  border: 2px solid rgba(255,255,255,0.5);
  border-radius: var(--radius-full);
  position: relative;
}

.wheel {
  width: 4px;
  height: 8px;
  background: rgba(255,255,255,0.5);
  border-radius: var(--radius-full);
  position: absolute;
  top: 6px;
  left: 50%;
  transform: translateX(-50%);
  animation: scrollWheel 2s infinite;
}

@keyframes scrollWheel {
  0% { opacity: 1; top: 6px; }
  100% { opacity: 0; top: 18px; }
}

@keyframes bounce {
  0%, 20%, 50%, 80%, 100% { transform: translateX(-50%) translateY(0); }
  40% { transform: translateX(-50%) translateY(-10px); }
  60% { transform: translateX(-50%) translateY(-5px); }
}

/* ------------------------------------------
   About Section
   ------------------------------------------ */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-12);
  align-items: start;
}

.about-text p {
  font-size: var(--text-lg);
  line-height: 1.8;
  margin-bottom: var(--space-4);
}

.about-highlights {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-4);
  margin-top: var(--space-8);
}

.highlight-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  text-align: center;
  transition: all var(--transition-base);
}

.highlight-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-primary);
}

.highlight-card i {
  font-size: var(--text-2xl);
  color: var(--color-primary);
  margin-bottom: var(--space-3);
}

.highlight-card h3 {
  font-size: var(--text-base);
  margin-bottom: var(--space-2);
}

.highlight-card p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-bottom: 0;
}

/* Code Window */
.code-window {
  background: var(--color-bg-code);
  border-radius: var(--radius-xl);
  overflow: hidden;
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-xl);
}

.code-header {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-4);
  background: var(--color-bg-alt);
  border-bottom: 1px solid var(--color-border);
}

.code-dot {
  width: 12px;
  height: 12px;
  border-radius: var(--radius-full);
}

.code-dot.red { background: #ff5f56; }
.code-dot.yellow { background: #ffbd2e; }
.code-dot.green { background: #27c93f; }

.code-filename {
  margin-left: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

.code-body {
  padding: var(--space-6);
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.6;
  color: var(--color-text);
}

.code-keyword { color: #c678dd; }
.code-class { color: #e5c07b; }
.code-function { color: #61afef; }
.code-string { color: #98c379; }

[data-theme="dark"] .code-keyword { color: #ff79c6; }
[data-theme="dark"] .code-class { color: #f1fa8c; }
[data-theme="dark"] .code-function { color: #8be9fd; }
[data-theme="dark"] .code-string { color: #50fa7b; }

@media (max-width: 768px) {
  .about-grid {
    grid-template-columns: 1fr;
  }

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

/* ------------------------------------------
   Skills Section
   ------------------------------------------ */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
}

.skill-category {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  transition: all var(--transition-base);
}

.skill-category:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-primary);
}

.skill-category-header {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-5);
  padding-bottom: var(--space-4);
  border-bottom: 1px solid var(--color-border);
}

.skill-icon-wrapper {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-lg);
  background: var(--color-primary-glow);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary);
  font-size: var(--text-lg);
}

.skill-category-header h3 {
  font-size: var(--text-lg);
  font-weight: var(--font-semibold);
}

.skill-items {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.skill-item {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
}

.skill-item:hover {
  background: var(--color-primary-glow);
  border-color: var(--color-primary);
  color: var(--color-primary);
  transform: scale(1.05);
}

.skill-item i {
  font-size: var(--text-base);
}

@media (max-width: 1024px) {
  .skills-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 640px) {
  .skills-grid {
    grid-template-columns: 1fr;
  }
}

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

.timeline-line {
  position: absolute;
  left: 50%;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--gradient-primary);
  transform: translateX(-50%);
}

.timeline-item {
  position: relative;
  display: flex;
  margin-bottom: var(--space-12);
}

.timeline-item:nth-child(odd) {
  flex-direction: row;
}

.timeline-item:nth-child(even) {
  flex-direction: row-reverse;
}

.timeline-marker {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  z-index: 2;
}

.timeline-dot {
  width: 16px;
  height: 16px;
  border-radius: var(--radius-full);
  background: var(--color-primary);
  border: 3px solid var(--color-bg);
  box-shadow: 0 0 0 3px var(--color-primary-glow);
}

.timeline-content {
  width: calc(50% - var(--space-8));
}

.timeline-item:nth-child(odd) .timeline-content {
  margin-right: auto;
  padding-right: var(--space-8);
  text-align: right;
}

.timeline-item:nth-child(even) .timeline-content {
  margin-left: auto;
  padding-left: var(--space-8);
  text-align: left;
}

.timeline-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  transition: all var(--transition-base);
}

.timeline-card:hover {
  box-shadow: var(--shadow-lg);
  border-color: var(--color-primary);
}

.timeline-date {
  margin-bottom: var(--space-3);
}

.date-badge {
  display: inline-block;
  background: var(--color-primary-glow);
  color: var(--color-primary);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: var(--font-semibold);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
}

.timeline-title {
  font-size: var(--text-xl);
  font-weight: var(--font-bold);
  margin-bottom: var(--space-1);
}

.timeline-org {
  font-size: var(--text-base);
  font-weight: var(--font-semibold);
  color: var(--color-primary);
  margin-bottom: var(--space-3);
}

.timeline-desc {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: 1.7;
  margin-bottom: var(--space-4);
}

.timeline-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.timeline-item:nth-child(odd) .timeline-tags {
  justify-content: flex-end;
}

.tag {
  display: inline-block;
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  font-weight: var(--font-medium);
  color: var(--color-text-muted);
}

@media (max-width: 768px) {
  .timeline-line {
    left: var(--space-4);
  }

  .timeline-item,
  .timeline-item:nth-child(odd),
  .timeline-item:nth-child(even) {
    flex-direction: column;
  }

  .timeline-marker {
    left: var(--space-4);
  }

  .timeline-content {
    width: 100%;
    padding-left: var(--space-12);
    padding-right: 0;
    text-align: left;
  }

  .timeline-item:nth-child(odd) .timeline-content,
  .timeline-item:nth-child(even) .timeline-content {
    margin: 0;
    padding-left: var(--space-12);
    padding-right: 0;
    text-align: left;
  }

  .timeline-item:nth-child(odd) .timeline-tags {
    justify-content: flex-start;
  }
}

/* ------------------------------------------
   Projects Section
   ------------------------------------------ */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-6);
}

.project-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  transition: all var(--transition-base);
  display: flex;
  flex-direction: column;
  height: 100%;
}

.project-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-xl);
  border-color: var(--color-primary);
}

.project-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-4);
}

.project-folder {
  font-size: var(--text-2xl);
  color: var(--color-primary);
}

.project-links {
  display: flex;
  gap: var(--space-3);
}

.project-link {
  color: var(--color-text-muted);
  font-size: var(--text-lg);
  transition: color var(--transition-fast), transform var(--transition-fast);
}

.project-link:hover {
  color: var(--color-primary);
  transform: translateY(-2px);
}

.project-title {
  font-size: var(--text-xl);
  font-weight: var(--font-bold);
  margin-bottom: var(--space-3);
}

.project-desc {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: 1.7;
  margin-bottom: var(--space-4);
  flex-grow: 1;
}

.project-metrics {
  display: flex;
  gap: var(--space-4);
  margin-bottom: var(--space-4);
}

.metric {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--text-xs);
  font-weight: var(--font-semibold);
  color: var(--color-secondary);
  background: rgba(13, 148, 136, 0.1);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
}

.metric i {
  font-size: 0.75em;
}

.project-tech {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.tech-tag {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  background: var(--color-bg-alt);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
}

@media (max-width: 768px) {
  .projects-grid {
    grid-template-columns: 1fr;
  }
}

/* ------------------------------------------
   Education Section
   ------------------------------------------ */
.education-grid {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: var(--space-8);
  margin-bottom: var(--space-12);
}

.education-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  text-align: center;
  transition: all var(--transition-base);
}

.education-card:hover {
  box-shadow: var(--shadow-lg);
  border-color: var(--color-primary);
}

.education-icon {
  width: 80px;
  height: 80px;
  border-radius: var(--radius-full);
  background: var(--gradient-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto var(--space-6);
  font-size: var(--text-3xl);
  color: white;
}

.education-content h3 {
  font-size: var(--text-2xl);
  margin-bottom: var(--space-2);
}

.education-degree {
  font-size: var(--text-lg);
  font-weight: var(--font-semibold);
  color: var(--color-primary);
  margin-bottom: var(--space-2);
}

.education-school {
  font-size: var(--text-base);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-4);
}

.education-meta {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.education-meta i {
  color: var(--color-primary);
  margin-right: var(--space-2);
}

.coursework-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
}

.coursework-card h3 {
  font-size: var(--text-xl);
  margin-bottom: var(--space-6);
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.coursework-card h3 i {
  color: var(--color-primary);
}

.coursework-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-3);
}

.course-item {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  background: var(--color-bg-alt);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-lg);
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
}

.course-item:hover {
  background: var(--color-primary-glow);
  color: var(--color-primary);
}

.course-item i {
  color: var(--color-primary);
  font-size: var(--text-sm);
}

.achievements-section {
  margin-top: var(--space-12);
}

.achievements-section h3 {
  font-size: var(--text-2xl);
  margin-bottom: var(--space-6);
  text-align: center;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-3);
}

.achievements-section h3 i {
  color: #f59e0b;
}

.achievements-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-6);
  max-width: 800px;
  margin: 0 auto;
}

.achievement-card {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  transition: all var(--transition-base);
}

.achievement-card:hover {
  box-shadow: var(--shadow-lg);
  border-color: #f59e0b;
}

.achievement-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-full);
  background: var(--color-bg-alt);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-xl);
  color: var(--color-primary);
  flex-shrink: 0;
}

.achievement-icon.gold {
  background: rgba(245, 158, 11, 0.15);
  color: #f59e0b;
}

.achievement-content h4 {
  font-size: var(--text-base);
  margin-bottom: var(--space-1);
}

.achievement-content p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-bottom: 0;
}

@media (max-width: 768px) {
  .education-grid {
    grid-template-columns: 1fr;
  }

  .coursework-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

@media (max-width: 480px) {
  .coursework-grid {
    grid-template-columns: 1fr;
  }
}

/* ------------------------------------------
   GitHub Section
   ------------------------------------------ */
.github-content {
  max-width: 900px;
  margin: 0 auto;
}

.github-profile {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  margin-bottom: var(--space-8);
}

.github-avatar {
  width: 80px;
  height: 80px;
  border-radius: var(--radius-full);
  background: var(--gradient-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-4xl);
  color: white;
  flex-shrink: 0;
}

.github-info h3 {
  font-size: var(--text-2xl);
  margin-bottom: var(--space-2);
}

.github-info p {
  color: var(--color-text-muted);
  margin-bottom: var(--space-4);
}

.github-stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-4);
  margin-bottom: var(--space-8);
}

.github-stat-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  text-align: center;
  transition: all var(--transition-base);
}

.github-stat-card:hover {
  border-color: var(--color-primary);
  transform: translateY(-2px);
}

.github-stat-card i {
  font-size: var(--text-2xl);
  color: var(--color-primary);
  margin-bottom: var(--space-3);
}

.github-stat-number {
  display: block;
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
  color: var(--color-text);
  margin-bottom: var(--space-1);
}

.github-stat-label {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-weight: var(--font-medium);
}

.github-contribution {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  margin-bottom: var(--space-8);
  text-align: center;
}

.github-contribution h4 {
  margin-bottom: var(--space-4);
  font-size: var(--text-lg);
}

.contribution-chart {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-lg);
}

.github-repos h4 {
  font-size: var(--text-lg);
  margin-bottom: var(--space-4);
  text-align: center;
}

.repos-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-4);
}

.repo-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  transition: all var(--transition-base);
}

.repo-card:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-md);
}

.repo-card h5 {
  font-size: var(--text-base);
  margin-bottom: var(--space-2);
  color: var(--color-primary);
}

.repo-card p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-3);
}

.repo-meta {
  display: flex;
  gap: var(--space-4);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

.repo-meta span {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.repo-placeholder {
  grid-column: 1 / -1;
  text-align: center;
  padding: var(--space-8);
  color: var(--color-text-muted);
}

@media (max-width: 768px) {
  .github-profile {
    flex-direction: column;
    text-align: center;
  }

  .github-stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

/* ------------------------------------------
   Resume Section
   ------------------------------------------ */
.resume-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-2xl);
  padding: var(--space-10);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-8);
  position: relative;
  overflow: hidden;
}

.resume-content {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  flex: 1;
}

.resume-icon {
  width: 64px;
  height: 64px;
  border-radius: var(--radius-full);
  background: var(--color-primary-glow);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-2xl);
  color: var(--color-primary);
  flex-shrink: 0;
}

.resume-text h2 {
  font-size: var(--text-2xl);
  margin-bottom: var(--space-2);
}

.resume-text p {
  color: var(--color-text-muted);
  margin-bottom: 0;
}

.resume-preview {
  width: 120px;
  flex-shrink: 0;
  opacity: 0.5;
}

.preview-page {
  background: var(--color-bg-alt);
  border-radius: var(--radius-md);
  padding: var(--space-3);
  border: 1px solid var(--color-border);
  transform: rotate(5deg);
}

.preview-header {
  height: 8px;
  background: var(--color-primary);
  border-radius: var(--radius-sm);
  margin-bottom: var(--space-2);
}

.preview-line {
  height: 4px;
  background: var(--color-border);
  border-radius: var(--radius-sm);
  margin-bottom: var(--space-1);
}

.preview-line.short {
  width: 60%;
}

@media (max-width: 768px) {
  .resume-card {
    flex-direction: column;
    text-align: center;
  }

  .resume-content {
    flex-direction: column;
  }

  .resume-preview {
    display: none;
  }
}

/* ------------------------------------------
   Contact Section
   ------------------------------------------ */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: var(--space-12);
  max-width: 1000px;
  margin: 0 auto;
}

.contact-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  height: 100%;
}

.contact-card h3 {
  font-size: var(--text-xl);
  margin-bottom: var(--space-4);
}

.contact-intro {
  color: var(--color-text-muted);
  margin-bottom: var(--space-6);
  line-height: 1.7;
}

.contact-items {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  margin-bottom: var(--space-8);
}

.contact-item {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-4);
  border-radius: var(--radius-lg);
  transition: all var(--transition-fast);
  text-decoration: none;
  color: inherit;
}

.contact-item:hover {
  background: var(--color-bg-alt);
}

.contact-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-full);
  background: var(--color-primary-glow);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary);
  font-size: var(--text-lg);
  flex-shrink: 0;
}

.contact-detail {
  display: flex;
  flex-direction: column;
}

.contact-label {
  font-size: var(--text-xs);
  font-weight: var(--font-semibold);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.contact-value {
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-text);
}

.contact-social h4 {
  font-size: var(--text-base);
  margin-bottom: var(--space-4);
}

.social-links {
  display: flex;
  gap: var(--space-3);
}

.social-link {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-full);
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-secondary);
  font-size: var(--text-lg);
  transition: all var(--transition-base);
}

.social-link:hover {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: white;
  transform: translateY(-3px);
  box-shadow: var(--shadow-glow);
}

/* Contact Form */
.contact-form-wrapper {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
}

.contact-form h3 {
  font-size: var(--text-xl);
  margin-bottom: var(--space-6);
}

.form-group {
  margin-bottom: var(--space-5);
}

.form-label {
  display: block;
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-text);
  margin-bottom: var(--space-2);
}

.form-input,
.form-textarea {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  font-family: var(--font-sans);
  font-size: var(--text-base);
  color: var(--color-text);
  transition: all var(--transition-base);
}

.form-input:focus,
.form-textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-glow);
}

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

.form-note {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-top: var(--space-4);
  text-align: center;
}

.form-note code {
  background: var(--color-bg-alt);
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
}

@media (max-width: 768px) {
  .contact-grid {
    grid-template-columns: 1fr;
  }
}

/* ------------------------------------------
   Footer
   ------------------------------------------ */
.footer {
  background: var(--color-bg-alt);
  border-top: 1px solid var(--color-border);
  padding: var(--space-16) 0 var(--space-8);
}

.footer-content {
  display: grid;
  grid-template-columns: 1.5fr 1fr;
  gap: var(--space-12);
  margin-bottom: var(--space-12);
}

.footer-brand .footer-logo {
  font-family: var(--font-mono);
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
  color: var(--color-text);
  text-decoration: none;
  display: inline-block;
  margin-bottom: var(--space-4);
}

.footer-brand p {
  color: var(--color-text-muted);
  max-width: 300px;
}

.footer-links {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-8);
}

.footer-column h4 {
  font-size: var(--text-sm);
  font-weight: var(--font-semibold);
  color: var(--color-text);
  margin-bottom: var(--space-4);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.footer-column ul {
  list-style: none;
}

.footer-column li {
  margin-bottom: var(--space-3);
}

.footer-column a {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  text-align: center;
  padding-top: var(--space-8);
  border-top: 1px solid var(--color-border);
}

.footer-bottom p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-1);
}

@media (max-width: 768px) {
  .footer-content {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }

  .footer-links {
    gap: var(--space-6);
  }
}

/* ------------------------------------------
   Back to Top Button
   ------------------------------------------ */
.back-to-top {
  position: fixed;
  bottom: var(--space-6);
  right: var(--space-6);
  width: 48px;
  height: 48px;
  border-radius: var(--radius-full);
  background: var(--color-primary);
  color: white;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-lg);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: all var(--transition-base);
  z-index: var(--z-fixed);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--color-primary-dark);
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
}

/* ------------------------------------------
   Animation Utilities
   ------------------------------------------ */
[data-animate] {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

[data-animate="fade-right"] {
  transform: translateX(-30px);
}

[data-animate="fade-left"] {
  transform: translateX(30px);
}

[data-animate].animated {
  opacity: 1;
  transform: translateY(0) translateX(0);
}

/* Stagger delays */
[data-delay="100"] { transition-delay: 100ms; }
[data-delay="200"] { transition-delay: 200ms; }
[data-delay="300"] { transition-delay: 300ms; }
[data-delay="400"] { transition-delay: 400ms; }
[data-delay="500"] { transition-delay: 500ms; }

/* ------------------------------------------
   Utility Classes
   ------------------------------------------ */
.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;
}

.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.hidden { display: none !important; }

/* ------------------------------------------
   Print Styles
   ------------------------------------------ */
@media print {
  .navbar,
  .hero-background,
  .scroll-indicator,
  .back-to-top,
  .theme-toggle,
  .mobile-toggle,
  .contact-form-wrapper,
  .footer {
    display: none !important;
  }

  .section {
    padding: var(--space-8) 0;
    page-break-inside: avoid;
  }

  body {
    background: white;
    color: black;
  }
}