/* Base Styles */
:root {
  --primary-color: #333;
  --secondary-color: #666;
  --accent-color: #4a4a4a;
  --background-color: #fff;
  --background-alt: #f5f5f5;
  --border-color: #e0e0e0;
  --success-color: #4caf50;
  --error-color: #f44336;
  --transition-speed: 0.3s;
  --header-height-desktop: 70px;
  --header-height-mobile: 60px;
  --header-height-scrolled: 60px;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 4rem;
}

body {
  font-family: "Inter", sans-serif;
  line-height: 1.6;
  color: var(--primary-color);
  background-color: var(--background-color);
  overflow-x: hidden;
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

section {
  padding: 80px 0;
}

.section-alt {
  background-color: var(--background-alt);
}

.section-title {
  font-size: 2rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 40px;
}

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

/* Header & Navigation */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background-color: var(--background-color);
  z-index: 1000;
  transition: all var(--transition-speed);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  height: var(--header-height-desktop);
  display: flex;
  align-items: center;
}

.header .container {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100%;
}

.header.scrolled {
  height: var(--header-height-scrolled);
}

.desktop-nav {
  display: none;
}

.nav-link {
  margin: 0 15px;
  text-decoration: none;
  color: var(--primary-color);
  font-weight: 500;
  position: relative;
  transition: color var(--transition-speed);
}

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

.nav-link::after {
  content: "";
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--accent-color);
  transition: width var(--transition-speed);
}

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

/* Improved Mobile Menu Button */
.mobile-menu-btn {
  position: absolute;
  right: 20px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  width: 30px;
  height: 21px;
  background: transparent;
  border: none;
  cursor: pointer;
  z-index: 1001;
  padding: 0;
}

.mobile-menu-btn span {
  display: block;
  width: 100%;
  height: 3px;
  background-color: var(--primary-color);
  transition: all 0.3s ease-in-out;
  border-radius: 2px;
}

.mobile-menu-btn.active span:nth-child(1) {
  transform: translateY(9px) rotate(45deg);
}

.mobile-menu-btn.active span:nth-child(2) {
  opacity: 0;
}

.mobile-menu-btn.active span:nth-child(3) {
  transform: translateY(-9px) rotate(-45deg);
}

/* Improved Mobile Menu */
.mobile-menu {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(255, 255, 255, 0.98);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  z-index: 999;
  transform: translateY(-100%);
  transition: transform 0.4s ease-in-out;
  overflow-y: auto;
}

.mobile-menu.active {
  transform: translateY(0);
}

.mobile-menu-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 100%;
  padding: 20px;
}

.mobile-nav-link {
  display: block;
  margin: 15px 0;
  font-size: 1.2rem;
  text-decoration: none;
  color: var(--primary-color);
  transition: color var(--transition-speed);
  text-align: center;
  padding: 10px;
  width: 100%;
}

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

/* Hero Section */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 100px 0;
}

.hero-content {
  max-width: 800px;
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.8s, transform 0.8s;
  margin: 0 auto;
  width: 100%;
  text-align: center;
}

.hero-content.visible {
  opacity: 1;
  transform: translateY(0);
}

.hero h1 {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 10px;
  line-height: 1.2;
  text-align: center;
}

.hero h2 {
  font-size: 1.5rem;
  font-weight: 500;
  color: var(--secondary-color);
  margin-bottom: 20px;
  text-align: center;
}

.hero p {
  font-size: 1.1rem;
  color: var(--secondary-color);
  margin-bottom: 30px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
  text-align: center;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
}

.tag {
  display: inline-block;
  padding: 5px 10px;
  background-color: #f0f0f0;
  color: var(--secondary-color);
  font-size: 0.8rem;
  border-radius: 4px;
}

/* About Section */
.about p {
  margin-bottom: 20px;
  color: var(--secondary-color);
}

/* Timeline Sections (Experience, Education, Honors) */
.timeline {
  position: relative;
  max-width: 800px;
  margin: 0 auto;
}

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

.timeline-item {
  position: relative;
  padding-left: 30px;
  margin-bottom: 40px;
}

.timeline-marker {
  position: absolute;
  top: 5px;
  left: -4px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: var(--accent-color);
}

.timeline-content h3 {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 5px;
}

.timeline-content .company,
.timeline-content .degree,
.timeline-content .honor-details {
  font-size: 1rem;
  color: var(--secondary-color);
  margin-bottom: 5px;
}

.timeline-content .period,
.timeline-content .field,
.timeline-content .location,
.timeline-content .honor-association {
  font-size: 0.9rem;
  color: var(--secondary-color);
  margin-bottom: 10px;
}

.timeline-content p {
  font-size: 0.95rem;
  color: var(--secondary-color);
}

/* Certifications Section */
.accordion {
  max-width: 800px;
  margin: 0 auto;
}

.accordion-item {
  margin-bottom: 15px;
  border: 1px solid var(--border-color);
  border-radius: 4px;
  overflow: hidden;
}

.accordion-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
  padding: 15px 20px;
  background-color: #f9f9f9;
  border: none;
  text-align: left;
  cursor: pointer;
  transition: background-color var(--transition-speed);
}

.accordion-header:hover {
  background-color: #f0f0f0;
}

.accordion-header h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin: 0;
}

.accordion-icon {
  font-size: 1.5rem;
  transition: transform var(--transition-speed);
}

.accordion-item.active .accordion-icon {
  transform: rotate(180deg);
}

.accordion-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-speed);
}

.accordion-item.active .accordion-content {
  max-height: 2000px;
}

.cert-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 15px;
  padding: 20px;
}

.cert-item {
  padding-bottom: 15px;
  border-bottom: 1px solid var(--border-color);
}

.cert-item h4 {
  font-size: 1rem;
  font-weight: 500;
  margin-bottom: 5px;
}

.cert-issuer {
  font-size: 0.9rem;
  color: var(--secondary-color);
}

.cert-date {
  font-size: 0.8rem;
  color: var(--secondary-color);
}

/* Projects Section */
.projects-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 30px;
  max-width: 800px;
  margin: 0 auto;
}

.project-card {
  border: 1px solid var(--border-color);
  padding: 20px;
  background-color: var(--background-color);
  transition: transform var(--transition-speed), box-shadow var(--transition-speed);
}

.project-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.05);
}

.project-card h3 {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 5px;
}

.project-period {
  font-size: 0.9rem;
  color: var(--secondary-color);
  margin-bottom: 15px;
}

.project-card p {
  font-size: 0.95rem;
  color: var(--secondary-color);
  margin-bottom: 15px;
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

/* Skills Section */
.skills-container {
  max-width: 800px;
  margin: 0 auto;
}

.skill-category {
  margin-bottom: 30px;
}

.skill-category h3 {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 15px;
}

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

/* Skill tag endorsement styling */
.skill-tags .tag {
  display: inline-flex;
  align-items: center;
  padding: 5px 10px;
  background-color: #f0f0f0;
  color: var(--secondary-color);
  font-size: 0.8rem;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.2s ease-in-out;
  position: relative;
  user-select: none;
}

.skill-tags .tag:hover {
  background-color: #e5e5e5;
  transform: translateY(-2px);
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.skill-tags .tag.endorsed {
  background-color: #e8f4fc;
  border: 1px solid #b8d8f8;
}

.skill-tags .tag .endorsement-count {
  margin-left: 5px;
  background-color: rgba(0,0,0,0.1);
  border-radius: 10px;
  padding: 0 6px;
  font-size: 0.7rem;
  line-height: 1.5;
  min-width: 18px;
  text-align: center;
  font-weight: 500;
}

.skill-tags .tag.endorsed .endorsement-count {
  background-color: rgba(76, 139, 245, 0.2);
}

/* Animate the count change */
@keyframes pulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.2); }
  100% { transform: scale(1); }
}

.skill-tags .tag .endorsement-count.animate {
  animation: pulse 0.4s ease-in-out;
}

/* Publications Section */
.publications-grid {
  max-width: 800px;
  margin: 0 auto;
}

.publication-card {
  border: 1px solid var(--border-color);
  padding: 20px;
  background-color: var(--background-color);
  margin-bottom: 20px;
}

.publication-card h3 {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 10px;
}

.publication-publisher {
  font-size: 0.95rem;
  color: var(--secondary-color);
  margin-bottom: 5px;
}

.publication-date {
  font-size: 0.9rem;
  color: var(--secondary-color);
  margin-bottom: 15px;
}

.publication-link {
  display: inline-block;
  color: var(--accent-color);
  text-decoration: none;
  font-size: 0.9rem;
}

.publication-link:hover {
  text-decoration: underline;
}

/* Languages Section */
.languages-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 20px;
  max-width: 800px;
  margin: 0 auto;
}

.language-card {
  border: 1px solid var(--border-color);
  padding: 15px;
  background-color: var(--background-color);
}

.language-card h3 {
  font-size: 1.1rem;
  font-weight: 500;
  margin-bottom: 5px;
}

.language-proficiency {
  font-size: 0.9rem;
  color: var(--secondary-color);
}

/* Contact Section */
.contact-info {
  text-align: center;
  margin-bottom: 40px;
}

.contact-item {
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 15px;
}

.contact-item i {
  margin-right: 10px;
  color: var(--secondary-color);
}

.contact-social {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-top: 20px;
}

.contact-social a {
  color: var(--secondary-color);
  font-size: 1.5rem;
  transition: color var(--transition-speed);
}

.contact-social a:hover {
  color: var(--accent-color);
}

.contact-form {
  max-width: 600px;
  margin: 0 auto;
}

.form-group {
  margin-bottom: 20px;
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 12px 15px;
  border: 1px solid var(--border-color);
  border-radius: 4px;
  font-family: "Inter", sans-serif;
  font-size: 1rem;
  background-color: #f9f9f9;
  transition: border-color var(--transition-speed);
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--accent-color);
}

.form-group textarea {
  min-height: 150px;
  resize: vertical;
}

.error-message {
  color: var(--error-color);
  font-size: 0.8rem;
  margin-top: 5px;
  display: none;
}

.submit-btn {
  display: block;
  width: 100%;
  padding: 12px;
  background-color: var(--primary-color);
  color: white;
  border: none;
  border-radius: 4px;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: background-color var(--transition-speed);
}

.submit-btn:hover {
  background-color: var(--accent-color);
}

.submit-btn:disabled {
  background-color: #ccc;
  cursor: not-allowed;
}

.form-status {
  margin-top: 15px;
  padding: 10px;
  border-radius: 4px;
  text-align: center;
  display: none;
}

.form-status.success {
  background-color: rgba(76, 175, 80, 0.1);
  color: var(--success-color);
  display: block;
}

.form-status.error {
  background-color: rgba(244, 67, 54, 0.1);
  color: var(--error-color);
  display: block;
}

/* Footer */
.footer {
  background-color: var(--background-alt);
  padding: 30px 0;
  text-align: center;
  border-top: 1px solid var(--border-color);
}

.footer p {
  font-size: 0.9rem;
  color: var(--secondary-color);
}

/* Responsive Styles */
@media (min-width: 768px) {
  .desktop-nav {
    display: flex;
  }

  .mobile-menu-btn {
    display: none;
  }

  .hero h1 {
    font-size: 3.5rem;
  }

  .hero h2 {
    font-size: 1.8rem;
  }

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

  .timeline-item {
    padding-left: 50px;
  }

  .timeline::before {
    left: 20px;
  }

  .timeline-marker {
    left: 16px;
  }
}

@media (max-width: 767px) {
  section {
    padding: 60px 0;
  }

  .section-title {
    font-size: 1.8rem;
    margin-bottom: 30px;
  }

  /* Fixed header height for mobile */
  .header {
    height: var(--header-height-mobile);
    min-height: var(--header-height-mobile);
  }

  .header.scrolled {
    height: var(--header-height-mobile);
    min-height: var(--header-height-mobile);
  }

  /* Adjust scroll padding to match header height */
  html {
    scroll-padding-top: var(--header-height-mobile);
  }

  .hero {
    padding: 80px 0 60px;
  }

  .hero h1 {
    font-size: 2.2rem;
  }

  .hero h2 {
    font-size: 1.3rem;
  }

  .hero p {
    font-size: 1rem;
  }

  .timeline-content h3 {
    font-size: 1.1rem;
  }

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

  /* Fix for mobile menu items */
  .mobile-menu-container {
    padding-top: 70px;
  }

  .mobile-nav-link {
    font-size: 1.4rem;
    padding: 12px 0;
  }

  /* Center the mobile menu button vertically */
  .mobile-menu-btn {
    top: 50%;
    transform: translateY(-50%);
  }
}

/* Animation Classes */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.8s, transform 0.8s;
}

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

.slide-in-left {
  opacity: 0;
  transform: translateX(-20px);
  transition: opacity 0.5s, transform 0.5s;
}

.slide-in-left.visible {
  opacity: 1;
  transform: translateX(0);
}

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

::-webkit-scrollbar-track {
  background: #f1f1f1;
}

::-webkit-scrollbar-thumb {
  background: #ddd;
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: #ccc;
}

/* Print Styles */
@media print {
  header,
  footer,
  #contact {
    display: none;
  }

  body {
    font-size: 12pt;
  }

  section {
    page-break-inside: avoid;
    padding: 1cm 0;
  }

  h2 {
    font-size: 16pt;
  }

  .container {
    width: 100%;
    max-width: none;
  }
}