/* ===== Reset & Base ===== */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --color-bg: #fafaf9;
  --color-text: #1c1917;
  --color-text-secondary: #57534e;
  --color-accent: #6366f1;
  --color-accent-light: #e0e7ff;
  --color-border: #e7e5e4;
  --color-card-bg: #ffffff;
  --color-tag-bg: #f5f5f4;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-serif: 'Lora', Georgia, 'Times New Roman', serif;
  --max-width: 820px;
  --transition: 0.2s ease;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background-color: var(--color-bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

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

a:hover {
  opacity: 0.75;
}

img {
  max-width: 100%;
  display: block;
}

/* ===== Layout ===== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ===== Navigation ===== */
nav {
  position: sticky;
  top: 0;
  background: rgba(250, 250, 249, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  z-index: 100;
  padding: 1rem 0;
}

nav .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

nav .logo {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--color-text);
}

nav .nav-links {
  display: flex;
  gap: 2rem;
  list-style: none;
}

nav .nav-links a {
  color: var(--color-text-secondary);
  font-size: 0.9rem;
  letter-spacing: 0.02em;
  transition: color var(--transition);
}

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

.menu-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.25rem;
}

.menu-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  margin: 5px 0;
  transition: var(--transition);
}

/* ===== Hero / Page Header ===== */
.hero {
  padding: 5rem 0 3rem;
}

.hero h1 {
  font-family: var(--font-serif);
  font-size: 2.75rem;
  font-weight: 600;
  line-height: 1.2;
  margin-bottom: 1rem;
}

.hero .subtitle {
  font-size: 1.15rem;
  color: var(--color-text-secondary);
  max-width: 600px;
  line-height: 1.7;
}

.hero .links {
  margin-top: 1.5rem;
  display: flex;
  gap: 1.25rem;
  flex-wrap: wrap;
}

.hero .links a {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  border: 1px solid var(--color-border);
  padding: 0.4rem 1rem;
  border-radius: 100px;
  transition: all var(--transition);
}

.hero .links a:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  opacity: 1;
}

/* ===== Sections ===== */
section {
  padding: 3rem 0;
}

section + section {
  border-top: 1px solid var(--color-border);
}

.section-title {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
}

/* ===== About (Home page) ===== */
.about-content {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

.about-content p {
  color: var(--color-text-secondary);
  font-size: 1.02rem;
}

.about-content p + p {
  margin-top: 0.75rem;
}

/* ===== Publication Groups ===== */
.pub-group {
  margin-bottom: 1.5rem;
}

.pub-group + .pub-group {
  padding-top: 1.25rem;
  border-top: 1px solid var(--color-border);
}

.pub-group-title {
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--color-accent);
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.pub-group .pub-item p {
  color: var(--color-text-secondary);
  font-size: 0.95rem;
  margin-bottom: 0.35rem;
}

/* ===== Cards (Projects, Blog) ===== */
.card-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

.card {
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: 1.75rem;
  transition: box-shadow var(--transition), transform var(--transition);
}

.card:hover {
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.04);
  transform: translateY(-2px);
}

.card .card-label {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-accent);
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.card h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.card p {
  color: var(--color-text-secondary);
  font-size: 0.95rem;
  line-height: 1.65;
}

.card .tags {
  margin-top: 1rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.card .tag {
  font-size: 0.78rem;
  background: var(--color-tag-bg);
  color: var(--color-text-secondary);
  padding: 0.25rem 0.7rem;
  border-radius: 100px;
}

/* ===== Timeline (Experience) ===== */
.timeline-item {
  position: relative;
  padding-left: 1.5rem;
  padding-bottom: 2rem;
  border-left: 2px solid var(--color-border);
}

.timeline-item:last-child {
  padding-bottom: 0;
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -5px;
  top: 6px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-accent);
}

.timeline-item h3 {
  font-size: 1.05rem;
  font-weight: 600;
}

.timeline-item .meta {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  margin-bottom: 0.5rem;
}

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

/* ===== Publications ===== */
.pub-item {
  padding: 1.25rem 0;
}

.pub-item + .pub-item {
  border-top: 1px solid var(--color-border);
}

.pub-item h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.pub-item .authors {
  font-size: 0.88rem;
  color: var(--color-text-secondary);
}

.pub-item .venue {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  font-style: italic;
  margin-top: 0.15rem;
}

/* ===== Skills / Tags list ===== */
.skills-group {
  margin-bottom: 1.25rem;
}

.skills-group h3 {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-secondary);
  margin-bottom: 0.5rem;
}

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

/* ===== Blog ===== */
.blog-post-preview {
  padding: 1.5rem 0;
}

.blog-post-preview + .blog-post-preview {
  border-top: 1px solid var(--color-border);
}

.blog-post-preview .date {
  font-size: 0.82rem;
  color: var(--color-text-secondary);
}

.blog-post-preview h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin: 0.25rem 0 0.5rem;
}

.blog-post-preview h3 a {
  color: var(--color-text);
}

.blog-post-preview h3 a:hover {
  color: var(--color-accent);
  opacity: 1;
}

.blog-post-preview p {
  color: var(--color-text-secondary);
  font-size: 0.95rem;
}

.empty-state {
  text-align: center;
  padding: 4rem 1rem;
  color: var(--color-text-secondary);
}

.empty-state p {
  font-size: 1.05rem;
  margin-bottom: 0.5rem;
}

.empty-state .small {
  font-size: 0.88rem;
}

/* ===== Awards ===== */
.awards-list {
  list-style: none;
}

.awards-list li {
  padding: 0.6rem 0;
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 1rem;
  font-size: 0.95rem;
}

.awards-list li + li {
  border-top: 1px solid var(--color-border);
}

.awards-list .year {
  color: var(--color-text-secondary);
  font-size: 0.85rem;
  white-space: nowrap;
}

/* ===== Footer ===== */
footer {
  border-top: 1px solid var(--color-border);
  padding: 2rem 0;
  margin-top: 3rem;
}

footer .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.85rem;
  color: var(--color-text-secondary);
}

footer .footer-links {
  display: flex;
  gap: 1.25rem;
  list-style: none;
}

footer .footer-links a {
  color: var(--color-text-secondary);
}

/* ===== Responsive ===== */
@media (max-width: 640px) {
  .hero h1 {
    font-size: 2rem;
  }

  .hero {
    padding: 3rem 0 2rem;
  }

  .menu-toggle {
    display: block;
  }

  nav .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    padding: 1rem 1.5rem;
    gap: 1rem;
  }

  nav .nav-links.open {
    display: flex;
  }

  footer .container {
    flex-direction: column;
    gap: 1rem;
    text-align: center;
  }

  .awards-list li {
    flex-direction: column;
    gap: 0.15rem;
  }
}