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

:root {
  --color-bg: #fafafa;
  --color-surface: #ffffff;
  --color-primary: #111111;
  --color-primary-light: #333333;
  --color-accent: #e8f4f8;
  --color-text: #111111;
  --color-text-light: #333333;
  --color-border: #dce8ed;
  --color-link: #111111;
  --font-heading: 'DM Serif Display', Georgia, serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --max-width: 960px;
  --nav-height: 72px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.1);
  --radius: 10px;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--color-link); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--color-primary-light); }

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

/* ===== TYPOGRAPHY ===== */
h1, h2, h3 { font-family: var(--font-heading); font-weight: 400; color: var(--color-text); }
h1 { font-size: 2.4rem; line-height: 1.2; }
h2 { font-size: 1.8rem; line-height: 1.3; margin-bottom: 1rem; }
h3 { font-size: 1.3rem; line-height: 1.4; margin-bottom: 0.5rem; }
p { margin-bottom: 1rem; }

/* ===== NAVIGATION ===== */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-height);
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
}

.nav-inner {
  width: 100%;
  max-width: var(--max-width);
  padding: 0 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-family: var(--font-heading);
  font-size: 1.3rem;
  color: var(--color-primary);
  letter-spacing: 0.02em;
}

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

.nav-links a {
  font-size: 0.9rem;
  color: var(--color-text-light);
  letter-spacing: 0.02em;
  position: relative;
  padding-bottom: 2px;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px; left: 0;
  width: 0; height: 2px;
  background: #7ec8e3;
  transition: width 0.25s ease;
}

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

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

/* Mobile nav toggle */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  margin: 6px 0;
  transition: 0.3s;
}

/* ===== LAYOUT ===== */
.page-wrapper {
  padding-top: var(--nav-height);
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 3rem 2rem;
}

.section { margin-bottom: 3rem; }

/* ===== HERO (Home page) ===== */
.hero {
  padding: 4rem 0 2rem;
  display: flex;
  gap: 3rem;
  align-items: flex-start;
}

.hero-photo {
  width: 200px;
  height: 200px;
  border-radius: 50%;
  object-fit: cover;
  border: 4px solid var(--color-accent);
  flex-shrink: 0;
}

.hero-placeholder {
  width: 200px;
  height: 200px;
  border-radius: 50%;
  background: linear-gradient(135deg, #7ec8e3, #a8dce8);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-family: var(--font-heading);
  font-size: 3rem;
  flex-shrink: 0;
}

.hero-text h1 {
  margin-bottom: 0.5rem;
}

.hero-subtitle {
  font-size: 1.1rem;
  color: var(--color-text-light);
  margin-bottom: 1.2rem;
}

.hero-links {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}

.hero-links a {
  font-size: 0.85rem;
  color: var(--color-text-light);
}

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

/* ===== CARDS ===== */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.8rem;
  margin-bottom: 1.2rem;
  transition: box-shadow 0.2s ease, transform 0.2s ease;
}

.card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-1px);
}

.card-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #111111;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.card h3 { margin-bottom: 0.4rem; }

.card p {
  color: var(--color-text-light);
  font-size: 0.95rem;
  margin-bottom: 0;
}

.card .meta {
  font-size: 0.85rem;
  color: var(--color-text-light);
  margin-top: 0.3rem;
}

/* ===== TAGS ===== */
.tags { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-top: 0.8rem; }

.tag {
  display: inline-block;
  background: var(--color-accent);
  color: #111111;
  font-size: 0.78rem;
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  font-weight: 600;
}

/* ===== PUBLICATION LIST ===== */
.pub-item {
  padding: 1.2rem 0;
  border-bottom: 1px solid var(--color-border);
}

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

.pub-item p {
  font-size: 0.95rem;
  line-height: 1.6;
  color: var(--color-text);
  margin-bottom: 0.3rem;
}

.pub-item .pub-link {
  font-size: 0.85rem;
  color: var(--color-primary);
  word-break: break-all;
}

.pub-year {
  display: inline-block;
  background: var(--color-accent);
  color: #111111;
  font-size: 0.78rem;
  font-weight: 700;
  padding: 0.15rem 0.6rem;
  border-radius: 4px;
  margin-bottom: 0.4rem;
}

/* ===== PAGE HEADER ===== */
.page-header {
  padding: 3rem 0 1.5rem;
  border-bottom: 2px solid var(--color-accent);
  margin-bottom: 2rem;
}

.page-header h1 { margin-bottom: 0.5rem; }
.page-header p { color: var(--color-text-light); font-size: 1.05rem; margin-bottom: 0; }

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

.timeline-item::before {
  content: '';
  position: absolute;
  left: -5px; top: 6px;
  width: 8px; height: 8px;
  border-radius: 50%;
  background: #7ec8e3;
}

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

.timeline-item h3 { font-size: 1.05rem; margin-bottom: 0.2rem; }
.timeline-item .meta { font-size: 0.85rem; color: var(--color-text-light); }

/* ===== GRID ===== */
.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.2rem;
}

.grid-3 {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 1rem;
}

/* ===== BUTTON ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.7rem 1.5rem;
  background: #7ec8e3;
  color: #111111;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  transition: background 0.2s, transform 0.15s;
  border: none;
  cursor: pointer;
}

.btn:hover {
  background: #5bb8d9;
  color: #111111;
  transform: translateY(-1px);
}

.btn-outline {
  background: transparent;
  color: #111111;
  border: 1.5px solid #111111;
}

.btn-outline:hover {
  background: var(--color-accent);
  color: #111111;
}

/* ===== CONTACT ===== */
.contact-info {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.contact-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.95rem;
}

.contact-icon {
  width: 40px;
  height: 40px;
  background: var(--color-accent);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-size: 1.1rem;
}

/* ===== FOOTER ===== */
.footer {
  border-top: 1px solid var(--color-border);
  padding: 2rem;
  text-align: center;
  font-size: 0.85rem;
  color: var(--color-text-light);
  margin-top: 2rem;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
  h1 { font-size: 1.8rem; }
  h2 { font-size: 1.4rem; }

  .hero {
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: 1.5rem;
    padding: 2rem 0 1rem;
  }

  .hero-placeholder, .hero-photo { width: 150px; height: 150px; font-size: 2.5rem; }
  .hero-links { justify-content: center; }

  .grid-2, .grid-3 { grid-template-columns: 1fr; }

  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0; right: 0;
    background: var(--color-surface);
    flex-direction: column;
    padding: 1rem 2rem;
    gap: 0.8rem;
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-md);
  }

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

  .nav-toggle { display: block; }

  .container { padding: 2rem 1.2rem; }
}