/* Global Styles */
body {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: #1a1a1a;
  color: #ffffff;
  line-height: 1.6;
  overflow-x: hidden;
  transition: background-color 0.3s, color 0.3s;
}

body.light-mode {
  background: #ffffff;
  color: #2c3e50;
}

/* Navigation */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: rgba(26, 26, 26, 0.95);
  backdrop-filter: blur(10px);
  z-index: 1000;
  padding: 20px 0;
  border-bottom: 1px solid #404040;
  transition: background-color 0.3s, border-color 0.3s;
}

body.light-mode .nav {
  background: rgba(255, 255, 255, 0.95);
  border-bottom: 1px solid #f0f0f0;
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 40px;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: #ffffff;
  transition: color 0.3s;
}

body.light-mode .logo {
  color: #2c3e50;
}

.nav-links {
  display: flex;
  gap: 40px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  text-decoration: none;
  color: #ffffff;
  font-weight: 500;
  transition: color 0.3s;
  position: relative;
}

body.light-mode .nav-links a {
  color: #2c3e50;
}

.nav-links a:hover {
  color: #3498db;
}

.nav-links a::after {
  content: "";
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background: #3498db;
  transition: width 0.3s;
}

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

.language-switcher {
  display: flex;
  gap: 5px;
  align-items: center;
}

.theme-toggle {
  background: transparent;
  border: 2px solid #3498db;
  color: #3498db;
  padding: 8px 12px;
  border-radius: 6px;
  cursor: pointer;
  font-weight: 600;
  font-size: 0.9rem;
  transition: all 0.3s;
  margin-right: 10px;
}

.theme-toggle:hover {
  background: #3498db;
  color: white;
}

.lang-btn {
  background: transparent;
  border: 2px solid #3498db;
  color: #3498db;
  padding: 8px 12px;
  border-radius: 6px;
  cursor: pointer;
  font-weight: 600;
  font-size: 0.9rem;
  transition: all 0.3s;
}

.lang-btn:hover {
  background: #3498db;
  color: white;
}

.lang-btn.active {
  background: #3498db;
  color: white;
}

/* Hero Section */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 120px 40px 80px;
  background: linear-gradient(135deg, #2a2a2a 0%, #1a1a1a 100%);
  transition: background 0.3s;
}

body.light-mode .hero {
  background: linear-gradient(135deg, #f8f9fa 0%, #ffffff 100%);
}

.hero-content {
  max-width: 800px;
  animation: fadeInUp 1s ease-out;
}

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

.hero-greeting {
  font-size: 1.2rem;
  color: #3498db;
  margin-bottom: 20px;
  font-weight: 500;
}

.hero-name {
  font-size: 4rem;
  font-weight: 800;
  color: #ffffff;
  margin-bottom: 20px;
  letter-spacing: -2px;
  transition: color 0.3s;
}

body.light-mode .hero-name {
  color: #2c3e50;
}

.hero-title {
  font-size: 1.5rem;
  color: #b0b0b0;
  margin-bottom: 40px;
  font-weight: 400;
  transition: color 0.3s;
}

body.light-mode .hero-title {
  color: #7f8c8d;
}

.hero-description {
  font-size: 1.1rem;
  color: #c0c0c0;
  margin-bottom: 50px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
  transition: color 0.3s;
}

body.light-mode .hero-description {
  color: #5a6c7d;
}

.cta-buttons {
  display: flex;
  gap: 20px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  padding: 15px 30px;
  border-radius: 8px;
  text-decoration: none;
  font-weight: 600;
  transition: all 0.3s;
  border: none;
  cursor: pointer;
  font-size: 1rem;
}

.btn-primary {
  background: #3498db;
  color: white;
}

.btn-primary:hover {
  background: #2980b9;
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(52, 152, 219, 0.3);
}

.btn-secondary {
  background: transparent;
  color: #3498db;
  border: 2px solid #3498db;
}

.btn-secondary:hover {
  background: #3498db;
  color: white;
  transform: translateY(-2px);
}

/* Sections */
.section {
  padding: 100px 40px;
  background: #1a1a1a;
  transition: background-color 0.3s;
}

body.light-mode .section {
  background: #ffffff;
}

.section.alt-bg {
  background: #222;
}

body.light-mode .section.alt-bg {
  background: #f8f9fa;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
}

.section-title {
  font-size: 2.5rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 20px;
  color: #ffffff;
  transition: color 0.3s;
}

body.light-mode .section-title {
  color: #2c3e50;
}

.section-subtitle {
  text-align: center;
  color: #b0b0b0;
  margin-bottom: 80px;
  font-size: 1.1rem;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
  transition: color 0.3s;
}

body.light-mode .section-subtitle {
  color: #7f8c8d;
}

/* Stats */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 40px;
  margin-bottom: 80px;
}

.stat-item {
  text-align: center;
  padding: 40px 20px;
  border-radius: 12px;
  background: #2a2a2a;
  transition: transform 0.3s, background-color 0.3s;
}

body.light-mode .stat-item {
  background: #f8f9fa;
}

.stat-item:hover {
  transform: translateY(-5px);
}

.stat-number {
  font-size: 3rem;
  font-weight: 800;
  color: #3498db;
  margin-bottom: 10px;
}

.stat-label {
  color: #c0c0c0;
  font-weight: 500;
  transition: color 0.3s;
}

body.light-mode .stat-label {
  color: #5a6c7d;
}

/* Experience */
.experience-grid {
  display: grid;
  gap: 40px;
}

.exp-card {
  background: #2a2a2a;
  border-radius: 16px;
  padding: 40px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
  border: 1px solid #404040;
  transition: all 0.3s;
  position: relative;
}

body.light-mode .exp-card {
  background: white;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
  border: 1px solid #f0f0f0;
}

.exp-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.4);
}

body.light-mode .exp-card:hover {
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.12);
}

.exp-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: #3498db;
  border-radius: 16px 16px 0 0;
}

.company-name {
  font-size: 1.5rem;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 8px;
  transition: color 0.3s;
}

body.light-mode .company-name {
  color: #2c3e50;
}

.position {
  font-size: 1.1rem;
  color: #3498db;
  margin-bottom: 8px;
  font-weight: 600;
}

.duration {
  color: #b0b0b0;
  margin-bottom: 20px;
  font-size: 0.95rem;
  transition: color 0.3s;
}

body.light-mode .duration {
  color: #7f8c8d;
}

.exp-description {
  color: #c0c0c0;
  margin-bottom: 20px;
  font-style: italic;
  transition: color 0.3s;
}

body.light-mode .exp-description {
  color: #5a6c7d;
}

.achievements {
  list-style: none;
  padding: 0;
}

.achievements li {
  margin-bottom: 12px;
  padding-left: 25px;
  position: relative;
  color: #c0c0c0;
  transition: color 0.3s;
}

body.light-mode .achievements li {
  color: #5a6c7d;
}

.achievements li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: #3498db;
  font-weight: bold;
}

/* Project Boxes */
.project-box {
  background: #404040;
  padding: 20px;
  border-radius: 8px;
  margin: 20px 0;
  transition: background-color 0.3s;
}

body.light-mode .project-box {
  background: #f8f9fa;
}

.project-box-railway {
  border-left: 4px solid #3498db;
}

.project-box-logistics {
  border-left: 4px solid #e74c3c;
}

.project-title {
  color: #ffffff;
  margin: 0 0 15px 0;
  font-size: 1.1rem;
  transition: color 0.3s;
}

body.light-mode .project-title {
  color: #2c3e50;
}

.project-achievements li {
  color: #e0e0e0;
  transition: color 0.3s;
}

body.light-mode .project-achievements li {
  color: #5a6c7d;
}

.technical-achievements {
  margin-top: 20px;
}

.technical-achievements-title {
  color: #3498db;
}

/* Skills */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 30px;
}

.skill-category {
  background: #2a2a2a;
  border-radius: 16px;
  padding: 30px;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
  border: 1px solid #404040;
  transition: background-color 0.3s, box-shadow 0.3s, border-color 0.3s;
}

body.light-mode .skill-category {
  background: white;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
  border: 1px solid #f0f0f0;
}

.skill-category h3 {
  font-size: 1.3rem;
  margin-bottom: 20px;
  color: #ffffff;
  font-weight: 600;
  transition: color 0.3s;
}

body.light-mode .skill-category h3 {
  color: #2c3e50;
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.skill-tag {
  background: #404040;
  color: #e0e0e0;
  padding: 8px 16px;
  border-radius: 20px;
  font-size: 0.9rem;
  font-weight: 500;
  border: 1px solid #555;
  transition: all 0.3s;
}

body.light-mode .skill-tag {
  background: #f8f9fa;
  color: #5a6c7d;
  border: 1px solid #e9ecef;
}

.skill-tag:hover {
  background: #3498db;
  color: white;
  transform: translateY(-2px);
}

/* Contact */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 30px;
  text-align: center;
}

.contact-item {
  background: #2a2a2a;
  border-radius: 16px;
  padding: 40px 30px;
  text-decoration: none;
  color: inherit;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
  border: 1px solid #404040;
  transition: all 0.3s;
}

body.light-mode .contact-item {
  background: white;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
  border: 1px solid #f0f0f0;
}

.contact-item:hover {
  transform: translateY(-5px);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.4);
}

body.light-mode .contact-item:hover {
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.12);
}

.contact-icon {
  font-size: 2.5rem;
  margin-bottom: 20px;
  display: block;
}

.contact-label {
  font-size: 1.1rem;
  font-weight: 600;
  color: #ffffff;
  margin-bottom: 8px;
  transition: color 0.3s;
}

body.light-mode .contact-label {
  color: #2c3e50;
}

.contact-value {
  color: #b0b0b0;
  font-size: 0.95rem;
  transition: color 0.3s;
}

body.light-mode .contact-value {
  color: #7f8c8d;
}

/* Animations */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: all 0.8s ease-out;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Mobile Menu */
.mobile-menu-toggle {
  display: none;
  background: transparent;
  border: none;
  color: #ffffff;
  font-size: 1.5rem;
  cursor: pointer;
  transition: color 0.3s;
}

body.light-mode .mobile-menu-toggle {
  color: #2c3e50;
}

.mobile-menu {
  position: fixed;
  top: 0;
  left: -100%;
  width: 80%;
  max-width: 400px;
  height: 100vh;
  background: #1a1a1a;
  z-index: 1002;
  transition: left 0.5s ease-in-out;
  padding: 80px 30px 30px;
  display: flex;
  flex-direction: column;
  gap: 30px;
  box-shadow: 2px 0 15px rgba(0, 0, 0, 0.3);
  overflow-y: auto;
}

body.light-mode .mobile-menu {
  background: #ffffff;
  box-shadow: 2px 0 15px rgba(0, 0, 0, 0.1);
}

.mobile-menu.active {
  left: 0;
}

.mobile-menu a {
  color: #ffffff;
  text-decoration: none;
  font-size: 1.2rem;
  font-weight: 500;
  padding: 15px 0;
  border-bottom: 1px solid #404040;
  transition: color 0.3s;
}

body.light-mode .mobile-menu a {
  color: #2c3e50;
  border-bottom: 1px solid #f0f0f0;
}

.mobile-menu a:hover {
  color: #3498db;
}

.mobile-controls {
  display: flex;
  gap: 10px;
  margin-top: 20px;
  flex-wrap: wrap;
}

.mobile-close {
  position: absolute;
  top: 20px;
  right: 20px;
  background: transparent;
  border: none;
  color: #ffffff;
  font-size: 2rem;
  cursor: pointer;
  transition: color 0.3s;
  z-index: 1003;
  line-height: 1;
  padding: 0;
}

body.light-mode .mobile-close {
  color: #2c3e50;
}

/* Scroll Indicator */
.scroll-indicator {
  position: fixed;
  top: 0;
  left: 0;
  width: 0%;
  height: 3px;
  background: #3498db;
  z-index: 1001;
  transition: width 0.3s;
}

/* Responsive */
@media (max-width: 768px) {
  .nav-links {
    display: none;
  }

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

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

  .section {
    padding: 60px 20px;
  }

  .nav-container {
    padding: 0 20px;
  }

  .cta-buttons {
    flex-direction: column;
    align-items: center;
  }
}