/* ===== CSS CUSTOM PROPERTIES ===== */
:root {
  /* Colors */
  --primary-color: #667eea;
  --secondary-color: #764ba2;
  --accent-color: #f093fb;
  --text-primary: #333333;
  --text-secondary: #666666;
  --text-light: #ffffff;
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
  --shadow-hover: 0 10px 30px rgba(0, 0, 0, 0.15);
  
  /* Typography */
  --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;
  --font-size-4xl: 2.5rem;
  --font-size-5xl: 3.5rem;
  
  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  --spacing-2xl: 4rem;
  --spacing-3xl: 6rem;
  
  /* Layout */
  --container-max-width: 1200px;
  --border-radius: 10px;
  --border-radius-full: 50px;
  
  /* Transitions */
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
  --transition-slow: 0.6s ease;
}

/* ===== RESET & BASE STYLES ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-primary);
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg-gradient);
  min-height: 100vh;
}

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

a {
  text-decoration: none;
  color: inherit;
}

/* ===== UTILITY CLASSES ===== */
.container {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.section {
  padding: var(--spacing-3xl) 0;
  background: var(--bg-primary);
}

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

.section-title {
  text-align: center;
  font-size: var(--font-size-4xl);
  font-weight: 700;
  margin-bottom: var(--spacing-xl);
  color: var(--text-primary);
  position: relative;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -10px;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 3px;
  background: var(--bg-gradient);
  border-radius: 2px;
}

/* ===== HEADER ===== */
#header {
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  position: fixed;
  top: 0;
  width: 100%;
  z-index: 1000;
  box-shadow: var(--shadow);
  transition: all var(--transition-normal);
}

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-sm) 0;
}

.logo {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--text-primary);
}

.nav-links {
  display: flex;
  list-style: none;
  gap: var(--spacing-lg);
}

.nav-links a {
  font-weight: 500;
  color: var(--text-primary);
  transition: color var(--transition-normal);
  position: relative;
}

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

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary-color);
  transition: width var(--transition-normal);
}

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

.mobile-menu-btn {
  display: none;
  flex-direction: column;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-xs);
}

.mobile-menu-btn span {
  width: 25px;
  height: 3px;
  background: var(--text-primary);
  margin: 3px 0;
  transition: var(--transition-normal);
}

/* ===== HERO SECTION ===== */
.hero {
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  color: var(--text-light);
  position: relative;
  overflow: hidden;
}

.hero-bg-animation {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(-45deg, #667eea, #764ba2, #f093fb, #667eea);
  background-size: 400% 400%;
  animation: gradientShift 15s ease infinite;
  z-index: -1;
}

@keyframes gradientShift {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

.hero-content {
  max-width: 800px;
  z-index: 1;
}

.hero-title {
  font-size: var(--font-size-5xl);
  font-weight: 700;
  margin-bottom: var(--spacing-sm);
  opacity: 0;
  animation: fadeInUp 1s ease 0.5s forwards;
}

.hero-subtitle {
  font-size: var(--font-size-2xl);
  font-weight: 300;
  margin-bottom: var(--spacing-lg);
  opacity: 0;
  animation: fadeInUp 1s ease 0.8s forwards;
}

.hero-description {
  font-size: var(--font-size-xl);
  font-weight: 300;
  margin-bottom: var(--spacing-lg);
  opacity: 0;
  animation: fadeInUp 1s ease 1.1s forwards;
  line-height: 1.8;
}

.cta-button {
  display: inline-block;
  padding: var(--spacing-md) var(--spacing-xl);
  background: rgba(255, 255, 255, 0.2);
  color: var(--text-light);
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-radius: var(--border-radius-full);
  font-weight: 600;
  font-size: var(--font-size-lg);
  transition: all var(--transition-normal);
  opacity: 0;
  animation: fadeInUp 1s ease 1.4s forwards;
}

.cta-button:hover {
  background: rgba(255, 255, 255, 0.3);
  transform: translateY(-2px);
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
}

/* ===== ABOUT SECTION ===== */
.about-content {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: var(--spacing-xl);
  align-items: center;
}

.profile-image {
  position: relative;
  width: 300px;
  height: 300px;
  margin: 0 auto;
}

.profile-image img {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  object-fit: cover;
  border: 5px solid var(--primary-color);
}

.profile-placeholder {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  background: var(--bg-gradient);
  display: none;
  align-items: center;
  justify-content: center;
  font-size: 4rem;
  color: var(--text-light);
}

.about-text h3 {
  font-size: var(--font-size-3xl);
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
  color: var(--text-primary);
}

.about-text p {
  margin-bottom: var(--spacing-sm);
  font-size: var(--font-size-lg);
  line-height: 1.8;
  color: var(--text-secondary);
}

.achievements {
  display: flex;
  gap: var(--spacing-lg);
  margin-top: var(--spacing-lg);
}

.achievement {
  text-align: center;
}

.achievement-number {
  display: block;
  font-size: var(--font-size-3xl);
  font-weight: 700;
  color: var(--primary-color);
}

.achievement-text {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  font-weight: 500;
}

/* ===== SKILLS SECTION ===== */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-lg);
}

.skill-category {
  background: var(--bg-primary);
  padding: var(--spacing-lg);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow);
  transition: all var(--transition-normal);
  text-align: center;
  border: 1px solid transparent;
}

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

.skill-icon {
  font-size: 3rem;
  margin-bottom: var(--spacing-sm);
}

.skill-category h3 {
  color: var(--text-primary);
  margin-bottom: var(--spacing-sm);
  font-size: var(--font-size-xl);
  font-weight: 600;
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  justify-content: center;
}

.skill-tag {
  background: #f0f2ff;
  color: var(--primary-color);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: 20px;
  font-size: var(--font-size-sm);
  font-weight: 500;
  transition: all var(--transition-fast);
}

.skill-tag:hover {
  background: var(--primary-color);
  color: var(--text-light);
  transform: scale(1.05);
}

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

.timeline::before {
  content: '';
  position: absolute;
  left: 50px;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--bg-gradient);
}

.experience-item {
  position: relative;
  margin-bottom: var(--spacing-xl);
  padding-left: 120px;
}

.experience-date {
  position: absolute;
  left: 0;
  top: 0;
  width: 80px;
  text-align: center;
  font-weight: 600;
  color: var(--primary-color);
  background: var(--bg-primary);
  padding: var(--spacing-xs);
  border-radius: var(--spacing-xs);
}

.experience-date::after {
  content: '';
  position: absolute;
  right: -15px;
  top: 50%;
  transform: translateY(-50%);
  width: 12px;
  height: 12px;
  background: var(--primary-color);
  border-radius: 50%;
  border: 3px solid var(--bg-primary);
}

.experience-content {
  background: var(--bg-primary);
  padding: var(--spacing-lg);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow);
  transition: all var(--transition-normal);
}

.experience-content:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-hover);
}

.experience-content h3 {
  color: var(--text-primary);
  margin-bottom: var(--spacing-xs);
  font-size: var(--font-size-xl);
  font-weight: 600;
}

.experience-meta {
  color: var(--primary-color);
  font-weight: 500;
  margin-bottom: var(--spacing-sm);
}

.experience-highlights {
  margin-top: var(--spacing-sm);
  padding-left: var(--spacing-md);
}

.experience-highlights li {
  margin-bottom: var(--spacing-xs);
  color: var(--text-secondary);
}

/* ===== EDUCATION SECTION ===== */
.education-item {
  position: relative;
  margin-bottom: var(--spacing-xl);
  padding-left: 120px;
}

.education-item .timeline-date {
  position: absolute;
  left: 0;
  top: 0;
  width: 80px;
  text-align: center;
  font-weight: 600;
  color: var(--secondary-color);
  background: var(--bg-primary);
  padding: var(--spacing-xs);
  border-radius: var(--spacing-xs);
}

.education-item .timeline-date::after {
  content: '';
  position: absolute;
  right: -15px;
  top: 50%;
  transform: translateY(-50%);
  width: 12px;
  height: 12px;
  background: var(--secondary-color);
  border-radius: 50%;
  border: 3px solid var(--bg-primary);
}

.education-item .timeline-content {
  background: var(--bg-primary);
  padding: var(--spacing-lg);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow);
  transition: all var(--transition-normal);
}

.education-item .timeline-content:hover {
  box-shadow: var(--shadow-hover);
  transform: scale(1.02);
}

.education-item .timeline-content h3 {
  color: var(--text-primary);
  margin-bottom: var(--spacing-xs);
  font-size: var(--font-size-xl);
  font-weight: 600;
}

.education-item .timeline-meta {
  color: var(--secondary-color);
  font-weight: 500;
  margin-bottom: var(--spacing-sm);
}

.education-highlights {
  margin-top: var(--spacing-sm);
  padding-left: var(--spacing-md);
}

.education-highlights li {
  margin-bottom: var(--spacing-xs);
  color: var(--text-secondary);
}

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

.project-card {
  background: var(--bg-primary);
  border-radius: var(--border-radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: all var(--transition-normal);
  border: 1px solid transparent;
}

.project-card:hover {
  transform: translateY(-10px);
  box-shadow: var(--shadow-hover);
  border-color: var(--primary-color);
}

.project-header {
  height: 200px;
  background: var(--bg-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
}

.project-icon {
  font-size: 4rem;
  color: var(--text-light);
  z-index: 1;
}

.project-content {
  padding: var(--spacing-md);
}

.project-content h3 {
  margin-bottom: var(--spacing-sm);
  color: var(--text-primary);
  font-size: var(--font-size-xl);
  font-weight: 600;
}

.project-content p {
  margin-bottom: var(--spacing-sm);
  color: var(--text-secondary);
  line-height: 1.7;
}

.project-tech {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  margin-bottom: var(--spacing-sm);
}

.tech-tag {
  background: #f0f2ff;
  color: var(--primary-color);
  padding: 0.25rem 0.75rem;
  border-radius: 15px;
  font-size: var(--font-size-xs);
  font-weight: 500;
}

.project-links {
  display: flex;
  gap: var(--spacing-sm);
}

.project-link {
  padding: var(--spacing-xs) var(--spacing-sm);
  background: var(--primary-color);
  color: var(--text-light);
  border-radius: var(--spacing-xs);
  font-size: var(--font-size-sm);
  font-weight: 500;
  transition: all var(--transition-normal);
}

.project-link:hover {
  background: var(--secondary-color);
  transform: translateY(-1px);
}

/* ===== CONTACT SECTION ===== */
.contact-content {
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
}

.contact-description {
  font-size: var(--font-size-lg);
  color: var(--text-secondary);
  margin-bottom: var(--spacing-lg);
  line-height: 1.8;
}

.contact-links {
  display: flex;
  justify-content: center;
  gap: var(--spacing-lg);
  flex-wrap: wrap;
}

.contact-link {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm) var(--spacing-lg);
  background: var(--primary-color);
  color: var(--text-light);
  border-radius: var(--border-radius-full);
  font-weight: 500;
  transition: all var(--transition-normal);
  min-width: 140px;
  justify-content: center;
}

.contact-link:hover {
  background: var(--secondary-color);
  transform: translateY(-3px);
  box-shadow: var(--shadow-hover);
}

.contact-icon {
  font-size: var(--font-size-lg);
}

/* ===== FOOTER ===== */
.footer {
  background: var(--text-primary);
  color: var(--text-light);
  padding: var(--spacing-lg) 0;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.footer-links {
  display: flex;
  gap: var(--spacing-lg);
}

.footer-links a {
  color: var(--text-light);
  font-size: var(--font-size-sm);
  transition: color var(--transition-normal);
}

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

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

@keyframes slideInLeft {
  from {
    opacity: 0;
    transform: translateX(-30px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

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

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

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

/* Tablet */
@media (max-width: 992px) {
  :root {
    --font-size-5xl: 3rem;
    --font-size-4xl: 2rem;
    --spacing-3xl: 4rem;
  }
  
  .about-content {
    grid-template-columns: 1fr;
    text-align: center;
  }
  
  .achievements {
    justify-content: center;
  }
  
  .timeline::before {
    left: 30px;
  }
  
  .experience-item {
    padding-left: 80px;
  }
  
  .experience-date {
    width: 60px;
    font-size: var(--font-size-sm);
  }
}

/* Mobile */
@media (max-width: 768px) {
  :root {
    --spacing-lg: 1rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 3rem;
  }
  
  .container {
    padding: 0 var(--spacing-sm);
  }
  
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background: var(--bg-primary);
    flex-direction: column;
    padding: var(--spacing-sm);
    box-shadow: var(--shadow);
  }
  
  .nav-links.active {
    display: flex;
  }
  
  .mobile-menu-btn {
    display: flex;
  }
  
  .mobile-menu-btn.active span:nth-child(1) {
    transform: rotate(-45deg) translate(-5px, 6px);
  }
  
  .mobile-menu-btn.active span:nth-child(2) {
    opacity: 0;
  }
  
  .mobile-menu-btn.active span:nth-child(3) {
    transform: rotate(45deg) translate(-5px, -6px);
  }
  
  .hero-title {
    font-size: var(--font-size-4xl);
  }
  
  .hero-subtitle {
    font-size: var(--font-size-xl);
  }
  
  .hero-description {
    font-size: var(--font-size-base);
  }
  
  .section-title {
    font-size: var(--font-size-3xl);
  }
  
  .profile-image {
    width: 250px;
    height: 250px;
  }
  
  .achievements {
    flex-direction: column;
    gap: var(--spacing-sm);
  }
  
  .skills-grid {
    grid-template-columns: 1fr;
  }
  
  .timeline::before {
    display: none;
  }
  
  .experience-item {
    padding-left: 0;
  }
  
  .experience-date {
    position: static;
    width: auto;
    margin-bottom: var(--spacing-xs);
    display: inline-block;
  }
  
  .experience-date::after {
    display: none;
  }
  
  .projects-grid {
    grid-template-columns: 1fr;
  }
  
  .contact-links {
    flex-direction: column;
    align-items: center;
  }
  
  .footer-content {
    flex-direction: column;
    text-align: center;
  }
}

/* Small Mobile */
@media (max-width: 480px) {
  .hero-title {
    font-size: var(--font-size-3xl);
  }
  
  .about-text h3 {
    font-size: var(--font-size-xl);
  }
  
  .profile-image {
    width: 200px;
    height: 200px;
  }
  
  .skill-category {
    padding: var(--spacing-sm);
  }
  
  .project-content {
    padding: var(--spacing-sm);
  }
}

/* ===== ACCESSIBILITY ===== */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  
  .hero-bg-animation {
    animation: none;
    background: var(--bg-gradient);
  }
}

/* Focus styles for keyboard navigation */
a:focus,
button:focus {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
  :root {
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.4);
  }
  
  .skill-tag,
  .tech-tag {
    border: 1px solid var(--primary-color);
  }
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
  :root {
    --text-primary: #e5e7eb;
    --text-secondary: #9ca3af;
    --text-light: #ffffff;
    --bg-primary: #1f2937;
    --bg-secondary: #111827;
    --shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
    --shadow-hover: 0 10px 30px rgba(0, 0, 0, 0.4);
  }
  
  #header {
    background: rgba(31, 41, 55, 0.95);
  }
  
  .skill-tag,
  .tech-tag {
    background: rgba(102, 126, 234, 0.2);
    color: #a5b4fc;
  }
}