/* =====================
   ROOT VARIABLES
===================== */
:root {
  --navy-dark:  #121F3D;
  --navy:       #1B2D5E;
  --navy-mid:   #243B7A;
  --gold:       #C4973A;
  --gold-light: #D4A94B;
  --white:      #FFFFFF;
  --gray-50:    #F6F7FB;
  --gray-100:   #ECEEF5;
  --gray-200:   #D8DCE9;
  --gray-400:   #8E97AE;
  --gray-600:   #5A6278;
  --gray-800:   #2D3446;
  --text:       #1E2535;
  --font-serif: 'Playfair Display', Georgia, 'Times New Roman', serif;
  --font-sans:  'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --nav-h:      64px;
  --radius:     8px;
  --shadow:     0 2px 12px rgba(27, 45, 94, 0.08);
  --shadow-md:  0 6px 28px rgba(27, 45, 94, 0.13);
  --transition: 0.2s ease;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-h);
}

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

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

ul { list-style: none; }

/* =====================
   CONTAINER
===================== */
.container {
  max-width: 1060px;
  margin: 0 auto;
  padding: 0 36px;
}

/* =====================
   NAVIGATION
===================== */
#navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 200;
  height: var(--nav-h);
  transition: background var(--transition), box-shadow var(--transition);
}

#navbar.scrolled {
  background: var(--navy-dark);
  box-shadow: 0 2px 24px rgba(0, 0, 0, 0.25);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: 1060px;
  margin: 0 auto;
  padding: 0 36px;
}

.nav-logo {
  font-family: var(--font-serif);
  font-size: 1rem;
  font-weight: 600;
  color: #fff;
  letter-spacing: 0.01em;
  white-space: nowrap;
}

.nav-logo:hover { color: var(--gold-light); }

.nav-links {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav-links a {
  color: rgba(255, 255, 255, 0.8);
  font-size: 0.875rem;
  font-weight: 500;
  letter-spacing: 0.025em;
  transition: color var(--transition);
}

.nav-links a:hover,
.nav-links a.active { color: #fff; }

.nav-cv {
  border: 1px solid rgba(255, 255, 255, 0.35);
  padding: 6px 18px;
  border-radius: 4px;
  transition: background var(--transition), border-color var(--transition), color var(--transition) !important;
}

.nav-cv:hover {
  background: #fff !important;
  color: var(--navy) !important;
  border-color: #fff;
}

.lang-toggle {
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.35);
  color: rgba(255, 255, 255, 0.85);
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  padding: 5px 12px;
  border-radius: 4px;
  cursor: pointer;
  transition: all var(--transition);
}

.lang-toggle:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.6);
  color: #fff;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: #fff;
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

/* =====================
   HERO
===================== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  overflow: hidden;
  background:
    radial-gradient(circle at 1px 1px, rgba(255,255,255,0.04) 1px, transparent 0) 0 0 / 36px 36px,
    linear-gradient(145deg, #0F1C38 0%, var(--navy-dark) 50%, #1a2a52 100%);
}

/* Decorative ring */
.hero::after {
  content: '';
  position: absolute;
  right: -120px;
  top: 50%;
  transform: translateY(-50%);
  width: 640px;
  height: 640px;
  border-radius: 50%;
  border: 1px solid rgba(196, 151, 58, 0.12);
  pointer-events: none;
}

.hero .container {
  position: relative;
  z-index: 1;
  padding-top: var(--nav-h);
}

.hero-content {
  max-width: 680px;
  padding: 88px 0 80px;
}

.hero-eyebrow {
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--gold);
  margin-bottom: 1.25rem;
}

.hero-name {
  font-family: var(--font-serif);
  font-size: clamp(2.6rem, 5.5vw, 4.2rem);
  font-weight: 700;
  color: #fff;
  line-height: 1.08;
  letter-spacing: -0.01em;
  margin-bottom: 1.25rem;
}

.hero-rule {
  width: 52px;
  height: 3px;
  background: var(--gold);
  border-radius: 2px;
  margin-bottom: 1.5rem;
}

.hero-tagline {
  font-size: 1.1rem;
  font-weight: 300;
  color: rgba(255, 255, 255, 0.72);
  line-height: 1.75;
  max-width: 540px;
  margin-bottom: 2.5rem;
}

.hero-actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 2.5rem;
}

/* =====================
   BUTTONS
===================== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4em;
  padding: 12px 28px;
  border-radius: 4px;
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 500;
  letter-spacing: 0.03em;
  transition: all var(--transition);
  cursor: pointer;
  border: none;
  white-space: nowrap;
}

.btn-gold {
  background: var(--gold);
  color: #fff;
}

.btn-gold:hover {
  background: var(--gold-light);
  color: #fff;
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(196, 151, 58, 0.4);
}

.btn-outline {
  background: transparent;
  color: #fff;
  border: 1px solid rgba(255, 255, 255, 0.38);
}

.btn-outline:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(255, 255, 255, 0.65);
  color: #fff;
}

.btn-navy {
  background: var(--navy);
  color: #fff;
  margin-top: 2rem;
}

.btn-navy:hover {
  background: var(--navy-mid);
  color: #fff;
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(27, 45, 94, 0.3);
}

/* =====================
   HERO TAGS
===================== */
.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
}

.hero-tags span {
  font-size: 0.77rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: rgba(255, 255, 255, 0.55);
  border: 1px solid rgba(255, 255, 255, 0.14);
  padding: 4px 13px;
  border-radius: 100px;
}

/* =====================
   SECTIONS (shared)
===================== */
.section       { padding: 96px 0; }
.section-white { background: var(--white); }
.section-light { background: var(--gray-50); }
.section-navy  { background: var(--navy-dark); }

.section-header        { margin-bottom: 3rem; }
.section-header.light  { }

.section-label {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--gold);
  margin-bottom: 0.5rem;
}

.section-header h2 {
  font-family: var(--font-serif);
  font-size: clamp(1.65rem, 3vw, 2.25rem);
  font-weight: 600;
  color: var(--navy-dark);
  line-height: 1.2;
}

.section-header.light h2 {
  color: rgba(255, 255, 255, 0.95);
}

/* =====================
   ABOUT
===================== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 4rem;
  align-items: start;
}

.about-bio p {
  font-size: 1rem;
  line-height: 1.85;
  color: var(--gray-800);
  margin-bottom: 1.25rem;
}

.about-bio p:last-child { margin-bottom: 0; }

.about-bio strong {
  color: var(--navy);
  font-weight: 600;
}

.info-card {
  background: var(--gray-50);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  padding: 20px 22px;
  margin-bottom: 1rem;
}

.info-card:last-child { margin-bottom: 0; }

.info-card h3 {
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--gold);
  margin-bottom: 0.55rem;
}

.info-card p {
  font-size: 0.88rem;
  color: var(--gray-600);
  line-height: 1.65;
}

.info-card p em {
  color: var(--gray-400);
  font-style: italic;
}

.info-card p a {
  color: var(--navy);
  border-bottom: 1px solid var(--gray-200);
  transition: color var(--transition), border-color var(--transition);
}

.info-card p a:hover {
  color: var(--gold);
  border-color: var(--gold);
}

.info-card ul li {
  font-size: 0.88rem;
  color: var(--gray-600);
  padding: 4px 0;
  border-bottom: 1px solid var(--gray-100);
  line-height: 1.5;
  display: flex;
  align-items: baseline;
  gap: 8px;
}

.info-card ul li:last-child { border-bottom: none; }

.info-card ul li::before {
  content: '•';
  color: var(--gold);
  font-weight: 600;
  flex-shrink: 0;
  font-size: 0.75rem;
}

/* =====================
   RESEARCH
===================== */
.research-featured {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-left: 4px solid var(--gold);
  border-radius: var(--radius);
  padding: 36px 40px;
  margin-bottom: 1.75rem;
  box-shadow: var(--shadow);
}

.featured-badge {
  display: inline-block;
  background: var(--gold);
  color: #fff;
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 3px 10px;
  border-radius: 3px;
  margin-bottom: 1rem;
}

.research-featured h3 {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--navy-dark);
  line-height: 1.25;
  margin-bottom: 0.4rem;
}

.research-role {
  font-size: 0.82rem;
  color: var(--gray-400);
  font-weight: 500;
  letter-spacing: 0.01em;
  margin-bottom: 1.25rem;
}

.research-featured p {
  font-size: 0.975rem;
  line-height: 1.85;
  color: var(--gray-800);
  margin-bottom: 1rem;
}

.research-featured p:last-of-type { margin-bottom: 0; }

.research-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-top: 1.4rem;
}

.research-tags span {
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--navy);
  background: rgba(27, 45, 94, 0.07);
  padding: 4px 12px;
  border-radius: 100px;
}

.research-tags.sm span {
  font-size: 0.73rem;
  padding: 3px 10px;
}

.research-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
}

.research-card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  padding: 28px 30px;
  transition: box-shadow var(--transition), transform var(--transition);
}

.research-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.research-date {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--gold);
  letter-spacing: 0.06em;
  margin-bottom: 0.55rem;
  text-transform: uppercase;
}

.research-card h4 {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--navy-dark);
  line-height: 1.3;
  margin-bottom: 0.75rem;
}

.research-card p {
  font-size: 0.9rem;
  color: var(--gray-600);
  line-height: 1.8;
  margin-bottom: 1rem;
}

/* =====================
   PRESENTATIONS
===================== */
.presentations-list { }

.presentation-item {
  display: grid;
  grid-template-columns: 110px 1fr;
  gap: 2.5rem;
  padding: 1.75rem 0;
  border-bottom: 1px solid var(--gray-100);
  align-items: start;
}

.presentation-item:first-child { border-top: 1px solid var(--gray-100); }

.presentation-meta {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding-top: 2px;
}

.presentation-year {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--navy);
}

.presentation-type {
  display: inline-block;
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--gold);
  background: rgba(196, 151, 58, 0.1);
  padding: 3px 9px;
  border-radius: 3px;
}

.citation {
  font-size: 0.96rem;
  line-height: 1.85;
  color: var(--gray-800);
}

.citation em { font-style: italic; }

/* =====================
   SKILLS
===================== */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 3rem;
}

.skill-group h4 {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.45);
  margin-bottom: 1.1rem;
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.skill-tags span {
  font-size: 0.82rem;
  color: rgba(255, 255, 255, 0.8);
  border: 1px solid rgba(255, 255, 255, 0.18);
  padding: 5px 14px;
  border-radius: 100px;
  transition: background var(--transition), border-color var(--transition);
}

.skill-tags span:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(255, 255, 255, 0.38);
}

/* =====================
   AWARDS
===================== */
.awards-list { max-width: 780px; }

.award-item {
  display: flex;
  align-items: baseline;
  gap: 1.75rem;
  padding: 0.85rem 0;
  border-bottom: 1px solid var(--gray-100);
}

.award-item:first-child { border-top: 1px solid var(--gray-100); }

.award-year {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--navy);
  min-width: 44px;
  flex-shrink: 0;
}

.award-name {
  font-size: 0.95rem;
  color: var(--gray-800);
  line-height: 1.5;
}

.award-value {
  color: var(--gray-400);
  font-size: 0.88rem;
  font-weight: 400;
}

/* =====================
   CONTACT
===================== */
.contact-content { max-width: 520px; }

.contact-content > p {
  font-size: 1rem;
  color: var(--gray-600);
  margin-bottom: 1.75rem;
  line-height: 1.75;
}

.contact-email {
  display: inline-block;
  font-size: 1.2rem;
  font-weight: 500;
  color: var(--navy);
  border-bottom: 2px solid var(--gold);
  padding-bottom: 2px;
  margin-bottom: 1.5rem;
  transition: color var(--transition);
}

.contact-email:hover { color: var(--gold); }

.contact-affil {
  font-size: 0.875rem;
  color: var(--gray-400);
  line-height: 1.75;
}

/* =====================
   FOOTER
===================== */
footer {
  background: var(--navy-dark);
  padding: 30px 0;
  text-align: center;
}

footer p {
  font-size: 0.8rem;
  color: rgba(255, 255, 255, 0.35);
  letter-spacing: 0.03em;
}

/* =====================
   RESPONSIVE — TABLET
===================== */
@media (max-width: 860px) {
  .about-grid {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }

  .skills-grid {
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
  }
}

/* =====================
   RESPONSIVE — MOBILE
===================== */
@media (max-width: 640px) {
  .container { padding: 0 20px; }

  .section { padding: 64px 0; }

  .hero-content { padding: 72px 0 64px; }

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

  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-h);
    left: 0; right: 0;
    background: var(--navy-dark);
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    padding: 0.5rem 0 1rem;
    box-shadow: 0 8px 24px rgba(0,0,0,0.2);
  }

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

  .nav-links li { width: 100%; }

  .nav-links a {
    display: block;
    padding: 12px 24px;
    font-size: 0.95rem;
  }

  .nav-links .nav-cv {
    margin: 8px 24px 0;
    display: inline-block;
    width: auto;
    padding: 8px 18px;
  }

  .nav-toggle { display: flex; }

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

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

  .presentation-item {
    grid-template-columns: 1fr;
    gap: 0.75rem;
  }

  .research-featured { padding: 24px; }

  .about-grid { gap: 2rem; }

  .award-item { gap: 1.25rem; }
}