/* Reset and Base Styles */
html {
  scroll-behavior: smooth;
  scroll-padding-top: 90px; /* Offset for sticky header */
}

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

:root {
  --color-bg: #fafbfc;
  --color-surface: #ffffff;
  --color-text-primary: #1e293b;
  --color-text-secondary: #475569;
  --color-text-tertiary: #64748b;
  --color-accent: #2563eb;
  --color-accent-light: #eff6ff;
  --color-border: #e2e8f0;
  --max-width: 1100px;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
}

body {
  background-color: var(--color-bg);
  color: var(--color-text-primary);
  font-family: var(--font-sans);
  line-height: 1.6;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Typography */
h1, h2, h3, h4 {
  font-weight: 700;
  letter-spacing: -0.025em;
  line-height: 1.25;
}

h1 {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
}

h2 {
  font-size: 1.75rem;
  margin-bottom: 1.5rem;
  position: relative;
  padding-bottom: 0.5rem;
}

h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 40px;
  height: 3px;
  background-color: var(--color-accent);
  border-radius: 2px;
}

h3 {
  font-size: 1.25rem;
  font-weight: 600;
}

p {
  color: var(--color-text-secondary);
  margin-bottom: 1rem;
}

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

a:hover {
  color: #1d4ed8;
}

/* Layout */
header {
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 1px 2px 0 rgba(0, 0, 0, 0.02);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text-primary);
}

nav ul {
  display: flex;
  list-style: none;
  gap: 1.5rem;
}

nav a {
  color: var(--color-text-secondary);
  font-size: 0.95rem;
  font-weight: 500;
}

nav a:hover, nav a.active {
  color: var(--color-accent);
}

main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 3rem 1.5rem;
}

section {
  padding: 3rem 0;
  border-bottom: 1px solid var(--color-border);
}

section:last-of-type {
  border-bottom: none;
}

/* Hero Section */
.hero {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  padding: 4rem 0;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--color-accent);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 0.5rem;
}

.tag {
  background-color: var(--color-accent-light);
  color: var(--color-accent);
  font-size: 0.85rem;
  font-weight: 600;
  padding: 0.35rem 0.85rem;
  border-radius: 9999px;
  letter-spacing: 0.02em;
}

.hero-summary {
  font-size: 1.15rem;
  max-width: 800px;
  line-height: 1.7;
}

.contact-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  margin-top: 1rem;
  font-size: 0.95rem;
}

.contact-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--color-text-secondary);
}

/* Cards & Grid Systems */
.grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

@media(min-width: 768px) {
  .grid-2 {
    grid-template-columns: repeat(2, 1fr);
  }
}

.card {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 1.75rem;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.02);
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.04), 0 4px 6px -4px rgba(0, 0, 0, 0.04);
}

/* Experience Timeline */
.timeline {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.timeline-item {
  border-left: 3px solid var(--color-border);
  padding-left: 1.5rem;
  position: relative;
  transition: border-color var(--transition-fast);
}

.timeline-item:hover {
  border-left-color: var(--color-accent);
}

.timeline-dot {
  position: absolute;
  left: -8px;
  top: 6px;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background-color: var(--color-bg);
  border: 3px solid var(--color-border);
  transition: border-color var(--transition-fast), background-color var(--transition-fast);
}

.timeline-item:hover .timeline-dot {
  border-color: var(--color-accent);
  background-color: var(--color-accent);
}

.timeline-meta {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 0.75rem;
}

.role-title {
  font-size: 1.15rem;
  color: var(--color-text-primary);
  font-weight: 600;
}

.company-name {
  color: var(--color-accent);
  font-weight: 600;
  font-size: 1.15rem;
}

.timeline-date {
  font-size: 0.85rem;
  color: var(--color-text-tertiary);
  font-weight: 500;
}

.timeline-item p {
  font-size: 0.95rem;
  color: var(--color-text-secondary);
  line-height: 1.5;
  margin-bottom: 0.5rem;
}

.timeline-details {
  margin-top: 0.5rem;
}

.timeline-details li {
  margin-bottom: 0.4rem;
  list-style-type: none;
  padding-left: 1rem;
  position: relative;
  font-size: 0.9rem;
  color: var(--color-text-secondary);
}

.timeline-details li::before {
  content: "•";
  color: var(--color-accent);
  position: absolute;
  left: 0;
}

/* Skills section styling */
.skills-container {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 1.5rem;
}

.skills-category h3 {
  border-bottom: 1px solid var(--color-border);
  padding-bottom: 0.5rem;
  margin-bottom: 1rem;
  color: var(--color-text-primary);
}

.skills-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.skill-tag {
  background-color: #f1f5f9;
  color: var(--color-text-secondary);
  font-size: 0.85rem;
  padding: 0.3rem 0.65rem;
  border-radius: 4px;
  border: 1px solid #e2e8f0;
}

/* Speaking and Publications */
.pub-item {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  padding: 1rem 0;
  border-bottom: 1px dashed var(--color-border);
}

.pub-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.pub-title {
  font-weight: 600;
  color: var(--color-text-primary);
}

.pub-meta {
  font-size: 0.85rem;
  color: var(--color-text-tertiary);
}

/* Footer & Utilities */
footer {
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: 2.5rem 1.5rem;
  text-align: center;
  color: var(--color-text-tertiary);
  font-size: 0.9rem;
}

.footer-container {
  max-width: var(--max-width);
  margin: 0 auto;
}

/* Animations */
.fade-in {
  opacity: 0;
  transform: translateY(10px);
  animation: fadeInUp 0.6s forwards;
}

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