/* ============================================
   CUSTOM PROPERTIES (CSS Variables)
   Theme: Light & Dark Mode
   ============================================ */

:root {
  /* Colors - Light Mode */
  --color-primary: #3B82F6;
  --color-primary-dark: #2563EB;
  --color-primary-light: #60A5FA;
  
  --color-text: #1F2937;
  --color-text-secondary: #6B7280;
  --color-text-tertiary: #9CA3AF;
  
  --color-bg: #FFFFFF;
  --color-bg-secondary: #F9FAFB;
  --color-bg-tertiary: #F3F4F6;
  
  --color-border: #E5E7EB;
  --color-border-light: #F3F4F6;
  
  --color-success: #10B981;
  --color-warning: #F59E0B;
  --color-error: #EF4444;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 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);
  
  /* Spacing */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2rem;
  --space-xl: 3rem;
  --space-2xl: 4rem;
  --space-3xl: 6rem;
  
  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', 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;
  
  /* Layout */
  --container-max: 1200px;
  --container-padding: 1.5rem;
  
  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 200ms ease;
  --transition-slow: 300ms ease;
  
  /* Z-index */
  --z-modal: 1000;
  --z-nav: 900;
  --z-dropdown: 800;
}

/* Dark Mode Variables */
[data-theme="dark"] {
  --color-text: #F9FAFB;
  --color-text-secondary: #D1D5DB;
  --color-text-tertiary: #9CA3AF;
  
  --color-bg: #111827;
  --color-bg-secondary: #1F2937;
  --color-bg-tertiary: #374151;
  
  --color-border: #374151;
  --color-border-light: #4B5563;
  
  --shadow-sm: 0 1px 2px 0 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, 0.5), 0 4px 6px -2px rgba(0, 0, 0, 0.4);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.6), 0 10px 10px -5px rgba(0, 0, 0, 0.5);
}

/* ============================================
   BASE STYLES
   ============================================ */

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

/* Container */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

/* Section Spacing */
section {
  padding: var(--space-2xl) 0;
}

/* Section Title & Subtitle */
.section__title {
  font-size: var(--text-4xl);
  font-weight: 700;
  text-align: center;
  margin-bottom: var(--space-md);
  color: var(--color-text);
}

.section__subtitle {
  font-size: var(--text-lg);
  text-align: center;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-2xl);
}

/* ============================================
   NAVIGATION
   ============================================ */

.nav {
  position: sticky;
  top: 0;
  z-index: var(--z-nav);
  background-color: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  backdrop-filter: blur(10px);
  background-color: rgba(255, 255, 255, 0.9);
  transition: all var(--transition-base);
}

[data-theme="dark"] .nav {
  background-color: rgba(17, 24, 39, 0.9);
}

.nav__container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--space-sm);
  padding-bottom: var(--space-sm);
  gap: var(--space-md);
}

.nav__logo {
  display: flex;
  align-items: center;
  font-weight: 700;
  font-size: var(--text-xl);
  color: var(--color-primary);
}

.nav__logo-text {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: white;
  border-radius: var(--radius-md);
  font-weight: 700;
}

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

.nav__link {
  font-weight: 500;
  color: var(--color-text-secondary);
  transition: color var(--transition-fast);
  position: relative;
  padding: var(--space-xs) 0;
}

.nav__link:hover,
.nav__link.active {
  color: var(--color-primary);
}

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

.nav__link:hover::after,
.nav__link.active::after {
  width: 100%;
}

/* Theme Toggle Button */
.theme-toggle {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  background-color: var(--color-bg-tertiary);
  color: var(--color-text);
  transition: all var(--transition-fast);
}

.theme-toggle:hover {
  background-color: var(--color-border);
  transform: rotate(20deg);
}

.theme-toggle__icon {
  width: 20px;
  height: 20px;
}

.theme-toggle__icon--moon {
  display: none;
}

[data-theme="dark"] .theme-toggle__icon--sun {
  display: none;
}

[data-theme="dark"] .theme-toggle__icon--moon {
  display: block;
}

/* Mobile Menu Toggle */
.nav__toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
}

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

/* ============================================
   HERO SECTION
   ============================================ */

.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  background: linear-gradient(135deg, 
    var(--color-bg) 0%, 
    var(--color-bg-secondary) 100%);
  overflow: hidden;
}

.hero__container {
  padding-top: var(--space-3xl);
  padding-bottom: var(--space-3xl);
}

.hero__content {
  max-width: 800px;
  margin: 0 auto;
  text-align: center;
}

.hero__greeting {
  font-size: var(--text-lg);
  color: var(--color-primary);
  font-weight: 600;
  margin-bottom: var(--space-sm);
}

.hero__title {
  font-size: clamp(var(--text-4xl), 8vw, var(--text-6xl));
  font-weight: 800;
  margin-bottom: var(--space-md);
  background: linear-gradient(135deg, var(--color-text), var(--color-text-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero__subtitle {
  font-size: clamp(var(--text-xl), 3vw, var(--text-3xl));
  font-weight: 600;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-lg);
}

.hero__description {
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
  max-width: 600px;
  margin: 0 auto var(--space-2xl);
  line-height: 1.8;
}

.hero__cta {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  flex-wrap: wrap;
}

.hero__scroll {
  position: absolute;
  bottom: var(--space-2xl);
  left: 50%;
  transform: translateX(-50%);
}

.hero__scroll-link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  color: var(--color-text-secondary);
  animation: bounce 2s infinite;
}

@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(10px); }
}

/* ============================================
   BUTTONS
   ============================================ */

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: 0.875rem 1.75rem;
  font-weight: 600;
  font-size: var(--text-base);
  border-radius: var(--radius-lg);
  transition: all var(--transition-base);
  cursor: pointer;
  border: 2px solid transparent;
}

.btn svg {
  width: 20px;
  height: 20px;
}

.btn--primary {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: white;
  box-shadow: var(--shadow-md);
}

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

.btn--secondary {
  background-color: var(--color-bg-tertiary);
  color: var(--color-text);
}

.btn--secondary:hover {
  background-color: var(--color-border);
}

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

.btn--ghost:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.btn--sm {
  padding: 0.5rem 1rem;
  font-size: var(--text-sm);
}

/* ============================================
   FEATURED PROJECTS SECTION
   ============================================ */

.featured {
  background-color: var(--color-bg-secondary);
}

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

.featured-card {
  background-color: var(--color-bg);
  border-radius: var(--radius-xl);
  padding: var(--space-xl);
  box-shadow: var(--shadow-lg);
  transition: all var(--transition-slow);
  border: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
}

.featured-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-xl);
}

.featured-card__header {
  margin-bottom: var(--space-lg);
}

.featured-card__badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: 0.375rem 0.75rem;
  background: linear-gradient(135deg, var(--color-primary-light), var(--color-primary));
  color: white;
  border-radius: var(--radius-full);
  font-size: var(--text-sm);
  font-weight: 600;
  margin-bottom: var(--space-md);
}

.featured-card__title {
  font-size: var(--text-3xl);
  font-weight: 700;
  margin-bottom: var(--space-xs);
  color: var(--color-text);
}

.featured-card__subtitle {
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-md);
}

.featured-card__description {
  font-size: var(--text-base);
  color: var(--color-text-secondary);
  line-height: 1.8;
  margin-bottom: var(--space-lg);
}

.featured-card__meta {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
  padding: var(--space-md);
  background-color: var(--color-bg-secondary);
  border-radius: var(--radius-md);
}

.featured-card__meta-item {
  display: flex;
  gap: var(--space-sm);
  font-size: var(--text-sm);
}

.featured-card__meta-label {
  font-weight: 600;
  color: var(--color-text);
  min-width: 80px;
}

.featured-card__meta-value {
  color: var(--color-text-secondary);
}

.featured-card__stack {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  margin-bottom: var(--space-lg);
}

.stack-tag {
  padding: 0.375rem 0.875rem;
  background-color: var(--color-bg-tertiary);
  color: var(--color-text-secondary);
  border-radius: var(--radius-full);
  font-size: var(--text-sm);
  font-weight: 500;
}

.featured-card__actions {
  display: flex;
  gap: var(--space-md);
  flex-wrap: wrap;
  margin-top: auto;
}

/* ============================================
   EXPERIENCE SECTION
   ============================================ */

.experience__timeline {
  max-width: 900px;
  margin: 0 auto;
  position: relative;
}

/* Timeline line */
.experience__timeline::before {
  content: '';
  position: absolute;
  left: 30px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(to bottom, var(--color-primary), var(--color-primary-light));
}

.experience-card {
  position: relative;
  padding-left: 80px;
  margin-bottom: var(--space-2xl);
  opacity: 0;
  transform: translateY(20px);
  transition: all var(--transition-slow);
}

.experience-card.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Timeline dot */
.experience-card::before {
  content: '';
  position: absolute;
  left: 21px;
  top: 8px;
  width: 20px;
  height: 20px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  border: 3px solid var(--color-bg);
  border-radius: 50%;
  box-shadow: var(--shadow-md);
  z-index: 1;
}

.experience-card--current::before {
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% {
    box-shadow: 0 0 0 0 rgba(59, 130, 246, 0.7);
  }
  50% {
    box-shadow: 0 0 0 10px rgba(59, 130, 246, 0);
  }
}

.experience-card__content {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  box-shadow: var(--shadow-md);
  transition: all var(--transition-base);
}

.experience-card__content:hover {
  box-shadow: var(--shadow-lg);
  transform: translateX(5px);
}

.experience-card__header {
  margin-bottom: var(--space-md);
}

.experience-card__company {
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--space-xs);
}

.experience-card__position {
  font-size: var(--text-lg);
  color: var(--color-primary);
  font-weight: 600;
  margin-bottom: var(--space-sm);
}

.experience-card__meta {
  display: flex;
  gap: var(--space-md);
  flex-wrap: wrap;
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
}

.experience-card__period,
.experience-card__location {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.experience-card__current-badge {
  display: inline-flex;
  padding: 0.25rem 0.75rem;
  background-color: var(--color-success);
  color: white;
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  font-weight: 600;
}

.experience-card__responsibilities {
  list-style: none;
  margin-top: var(--space-md);
}

.experience-card__responsibilities li {
  position: relative;
  padding-left: var(--space-lg);
  margin-bottom: var(--space-sm);
  color: var(--color-text-secondary);
  line-height: 1.7;
}

.experience-card__responsibilities li::before {
  content: '▹';
  position: absolute;
  left: 0;
  color: var(--color-primary);
  font-size: var(--text-lg);
}

/* ============================================
   PROJECTS SECTION
   ============================================ */

.projects {
  background-color: var(--color-bg-secondary);
}

.projects__filters {
  display: flex;
  gap: var(--space-sm);
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: var(--space-2xl);
}

.filter-btn {
  padding: 0.625rem 1.25rem;
  border-radius: var(--radius-full);
  background-color: var(--color-bg);
  color: var(--color-text-secondary);
  font-weight: 500;
  border: 2px solid transparent;
  transition: all var(--transition-fast);
}

.filter-btn:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.filter-btn--active {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: white;
  border-color: transparent;
}

.projects__grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--space-xl);
}

.project-card {
  background-color: var(--color-bg);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  border: 1px solid var(--color-border);
  transition: all var(--transition-slow);
  opacity: 0;
  transform: translateY(20px);
  display: flex;
  flex-direction: column;
}

.project-card.visible {
  opacity: 1;
  transform: translateY(0);
}

.project-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

.project-card__title {
  font-size: var(--text-xl);
  font-weight: 700;
  margin-bottom: var(--space-xs);
  color: var(--color-text);
}

.project-card__subtitle {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-md);
}

.project-card__description {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: 1.7;
  margin-bottom: var(--space-md);
}

.project-card__stack {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  margin-bottom: var(--space-md);
}

.project-card__actions {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
  margin-top: auto;
}

/* ============================================
   SKILLS SECTION
   ============================================ */

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

.skill-category {
  background-color: var(--color-bg);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  border: 1px solid var(--color-border);
  transition: all var(--transition-slow);
  opacity: 0;
  transform: scale(0.95);
}

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

.skill-category:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-5px);
}

.skill-category__header {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
}

.skill-category__icon {
  font-size: var(--text-3xl);
}

.skill-category__name {
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-text);
}

.skill-category__list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.skill-item {
  display: inline-flex;
  align-items: center;
  padding: var(--space-sm) var(--space-md);
  background-color: var(--color-bg-secondary);
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
  cursor: default;
}

.skill-item:hover {
  background-color: var(--color-bg-tertiary);
  transform: translateY(-2px);
}

.skill-item__name {
  font-weight: 500;
  color: var(--color-text);
}

.skill-item__evidence {
  display: none;
}

/* ============================================
   EDUCATION SECTION
   ============================================ */

.education {
  background-color: var(--color-bg-secondary);
}

.education__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
  gap: var(--space-xl);
  max-width: 900px;
  margin: 0 auto;
}

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

.education-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-3px);
}

.education-card__institution {
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--space-xs);
}

.education-card__degree {
  font-size: var(--text-lg);
  color: var(--color-primary);
  font-weight: 600;
  margin-bottom: var(--space-sm);
}

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

.education-card__specialization {
  font-size: var(--text-sm);
  color: var(--color-text-tertiary);
  margin-bottom: var(--space-md);
}

.education-card__meta {
  display: flex;
  gap: var(--space-md);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  padding-top: var(--space-md);
  border-top: 1px solid var(--color-border);
}

/* ============================================
   CONTACT SECTION
   ============================================ */

.contact__content {
  max-width: 700px;
  margin: 0 auto;
}

.contact__info {
  display: grid;
  gap: var(--space-lg);
  margin-top: var(--space-2xl);
}

.contact-item {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-lg);
  background-color: var(--color-bg-secondary);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  transition: all var(--transition-base);
}

.contact-item:hover {
  background-color: var(--color-bg-tertiary);
  transform: translateX(5px);
}

.contact-item__icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: white;
  border-radius: var(--radius-md);
  font-size: var(--text-xl);
  flex-shrink: 0;
}

.contact-item__content {
  flex: 1;
}

.contact-item__label {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin-bottom: 0.25rem;
}

.contact-item__value {
  font-size: var(--text-lg);
  font-weight: 600;
  color: var(--color-text);
}

.contact-item__value a {
  color: var(--color-primary);
  transition: color var(--transition-fast);
}

.contact-item__value a:hover {
  color: var(--color-primary-dark);
  text-decoration: underline;
}

/* ============================================
   FOOTER
   ============================================ */

.footer {
  background-color: var(--color-bg-secondary);
  border-top: 1px solid var(--color-border);
  padding: var(--space-2xl) 0;
}

.footer__content {
  text-align: center;
}

.footer__copyright {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-sm);
}

.footer__legal {
  font-size: var(--text-sm);
  color: var(--color-text-tertiary);
}

.footer__legal a {
  color: var(--color-primary);
  text-decoration: underline;
}

/* ============================================
   MODAL
   ============================================ */

.modal {
  position: fixed;
  inset: 0;
  z-index: var(--z-modal);
  display: none;
  align-items: center;
  justify-content: center;
  padding: var(--space-md);
}

.modal.active {
  display: flex;
}

.modal__overlay {
  position: absolute;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(4px);
  animation: fadeIn var(--transition-base);
}

.modal__container {
  position: relative;
  max-width: 900px;
  max-height: 90vh;
  width: 100%;
  background-color: var(--color-bg);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  overflow-y: auto;
  animation: slideUp var(--transition-slow);
  z-index: 1;
}

.modal__close {
  position: sticky;
  top: var(--space-md);
  right: var(--space-md);
  margin-left: auto;
  display: flex;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  background-color: var(--color-bg-tertiary);
  border-radius: var(--radius-md);
  z-index: 2;
  transition: all var(--transition-fast);
  float: right;
  margin-bottom: calc(-40px - var(--space-md));
}

.modal__close:hover {
  background-color: var(--color-error);
  color: white;
  transform: rotate(90deg);
}

.modal__content {
  padding: var(--space-2xl);
}

.modal__title {
  font-size: var(--text-2xl);
  font-weight: 700;
  margin-bottom: var(--space-lg);
  color: var(--color-text);
}

.modal__gallery {
  display: grid;
  gap: var(--space-lg);
}

.modal__image {
  width: 100%;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(50px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ============================================
   LIGHTBOX - Full Screen Image Viewer
   ============================================ */

.lightbox {
  position: fixed;
  inset: 0;
  z-index: calc(var(--z-modal) + 10);
  display: none;
  align-items: center;
  justify-content: center;
  background-color: rgba(0, 0, 0, 0.95);
  opacity: 0;
  transition: opacity var(--transition-base);
}

.lightbox.active {
  display: flex;
  opacity: 1;
}

.lightbox__overlay {
  position: absolute;
  inset: 0;
  cursor: zoom-out;
}

.lightbox__close {
  position: fixed;
  top: var(--space-lg);
  right: var(--space-lg);
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  background-color: rgba(0, 0, 0, 0.8);
  border-radius: var(--radius-full);
  color: white;
  transition: all var(--transition-fast);
}

.lightbox__close:hover {
  background-color: var(--color-error);
  transform: rotate(90deg) scale(1.1);
}

.lightbox__nav {
  position: fixed;
  top: 50%;
  transform: translateY(-50%);
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  background-color: rgba(0, 0, 0, 0.8);
  border-radius: var(--radius-full);
  color: white;
  transition: all var(--transition-fast);
  opacity: 0.7;
}

.lightbox__nav:hover {
  opacity: 1;
  background-color: var(--color-primary);
  transform: translateY(-50%) scale(1.1);
}

.lightbox__nav--prev {
  left: var(--space-lg);
}

.lightbox__nav--next {
  right: var(--space-lg);
}

.lightbox__nav.hidden {
  display: none;
}

.lightbox__image {
  max-width: 90vw;
  max-height: 90vh;
  object-fit: contain;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-2xl);
  animation: lightboxZoom var(--transition-slow);
}

.lightbox__counter {
  position: fixed;
  bottom: var(--space-lg);
  left: 50%;
  transform: translateX(-50%);
  z-index: 10;
  padding: var(--space-sm) var(--space-md);
  background-color: rgba(0, 0, 0, 0.8);
  border-radius: var(--radius-full);
  color: white;
  font-size: var(--text-sm);
  font-weight: 500;
}

@keyframes lightboxZoom {
  from {
    opacity: 0;
    transform: scale(0.8);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

/* ============================================
   ANIMATIONS & UTILITIES
   ============================================ */

.animate-fade-up {
  animation: fadeUp 0.8s ease-out;
}

@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Hidden class for accessibility */
.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;
}

/* ============================================
   RESPONSIVE DESIGN
   ============================================ */

@media (max-width: 768px) {
  :root {
    --container-padding: 1rem;
    --text-4xl: 2rem;
    --text-5xl: 2.5rem;
    --text-6xl: 3rem;
  }
  
  section {
    padding: var(--space-2xl) 0;
  }
  
  /* Navigation - Mobile */
  .nav__list {
    position: fixed;
    top: 60px;
    left: 0;
    right: 0;
    flex-direction: column;
    background-color: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-lg);
    gap: var(--space-md);
    transform: translateY(-100%);
    opacity: 0;
    transition: all var(--transition-base);
    pointer-events: none;
    box-shadow: var(--shadow-lg);
  }
  
  .nav__list.active {
    transform: translateY(0);
    opacity: 1;
    pointer-events: all;
  }
  
  .nav__toggle {
    display: flex;
  }
  
  .nav__toggle.active .nav__toggle-line:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
  }
  
  .nav__toggle.active .nav__toggle-line:nth-child(2) {
    opacity: 0;
  }
  
  .nav__toggle.active .nav__toggle-line:nth-child(3) {
    transform: rotate(-45deg) translate(6px, -6px);
  }
  
  /* Hero */
  .hero__cta {
    flex-direction: column;
    align-items: stretch;
  }
  
  .btn {
    width: 100%;
    justify-content: center;
  }
  
  /* Experience Timeline */
  .experience__timeline::before {
    left: 15px;
  }
  
  .experience-card {
    padding-left: 50px;
  }
  
  .experience-card::before {
    left: 6px;
  }
  
  /* Projects & Skills Grid */
  .projects__grid,
  .skills__grid,
  .featured__grid {
    grid-template-columns: 1fr;
  }
  
  .education__grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .featured-card {
    padding: var(--space-lg);
  }
  
  .featured-card__actions,
  .project-card__actions {
    flex-direction: column;
  }
  
  .btn {
    width: 100%;
    justify-content: center;
  }
}