/* ============================================================
   SION AN — ACADEMIC PORTFOLIO STYLESHEET
   Modern, clean academic blog/portfolio design
   ============================================================ */

/* ------------------------------------------------------------
   1. CSS CUSTOM PROPERTIES (Design Tokens)
   ------------------------------------------------------------ */
:root {
  /* Color Palette */
  --color-bg:            #ffffff;
  --color-bg-soft:       #f8fafc;
  --color-bg-muted:      #f1f5f9;
  --color-surface:       #ffffff;
  --color-surface-hover: #f8fafc;
  --color-border:        #e2e8f0;
  --color-border-strong: #cbd5e1;

  --color-text-primary:  #0f172a;
  --color-text-secondary:#475569;
  --color-text-muted:    #94a3b8;
  --color-text-inverse:  #ffffff;

  --color-accent:        #3b82f6;
  --color-accent-hover:  #2563eb;
  --color-accent-light:  #eff6ff;
  --color-accent-dark:   #1d4ed8;

  --color-heading:       #1a1a2e;

  /* Badge Colors */
  --badge-journal-bg:    #eff6ff;
  --badge-journal-text:  #1d4ed8;
  --badge-journal-border:#bfdbfe;

  --badge-conf-bg:       #f0fdf4;
  --badge-conf-text:     #15803d;
  --badge-conf-border:   #bbf7d0;

  --badge-workshop-bg:   #fff7ed;
  --badge-workshop-text: #c2410c;
  --badge-workshop-border:#fed7aa;

  --badge-domestic-bg:   #f8fafc;
  --badge-domestic-text: #475569;
  --badge-domestic-border:#e2e8f0;

  --badge-preprint-bg:   #fdf4ff;
  --badge-preprint-text: #7e22ce;
  --badge-preprint-border:#e9d5ff;

  /* Typography */
  --font-sans:    'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-heading: 'Lora', 'Georgia', 'Times New Roman', serif;
  --font-mono:    'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'Courier New', monospace;

  /* Font Sizes (fluid clamp scale) */
  --text-xs:   0.75rem;    /* 12px */
  --text-sm:   0.875rem;   /* 14px */
  --text-base: 1rem;       /* 16px */
  --text-lg:   1.125rem;   /* 18px */
  --text-xl:   1.25rem;    /* 20px */
  --text-2xl:  1.5rem;     /* 24px */
  --text-3xl:  1.875rem;   /* 30px */
  --text-4xl:  2.25rem;    /* 36px */

  /* Font Weights */
  --fw-normal:   400;
  --fw-medium:   500;
  --fw-semibold: 600;
  --fw-bold:     700;

  /* Line Heights */
  --lh-tight:  1.25;
  --lh-snug:   1.375;
  --lh-normal: 1.5;
  --lh-relaxed:1.625;
  --lh-loose:  2;

  /* Spacing Scale */
  --space-1:  0.25rem;   /* 4px */
  --space-2:  0.5rem;    /* 8px */
  --space-3:  0.75rem;   /* 12px */
  --space-4:  1rem;      /* 16px */
  --space-5:  1.25rem;   /* 20px */
  --space-6:  1.5rem;    /* 24px */
  --space-8:  2rem;      /* 32px */
  --space-10: 2.5rem;    /* 40px */
  --space-12: 3rem;      /* 48px */
  --space-16: 4rem;      /* 64px */
  --space-20: 5rem;      /* 80px */
  --space-24: 6rem;      /* 96px */

  /* Border Radius */
  --radius-sm:  0.25rem;   /* 4px */
  --radius-md:  0.375rem;  /* 6px */
  --radius-lg:  0.5rem;    /* 8px */
  --radius-xl:  0.75rem;   /* 12px */
  --radius-2xl: 1rem;      /* 16px */
  --radius-full:9999px;

  /* Shadows */
  --shadow-sm:   0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md:   0 4px 6px -1px rgb(0 0 0 / 0.07), 0 2px 4px -2px rgb(0 0 0 / 0.07);
  --shadow-lg:   0 10px 15px -3px rgb(0 0 0 / 0.08), 0 4px 6px -4px rgb(0 0 0 / 0.05);
  --shadow-xl:   0 20px 25px -5px rgb(0 0 0 / 0.08), 0 8px 10px -6px rgb(0 0 0 / 0.05);
  --shadow-inset:inset 0 1px 2px 0 rgb(0 0 0 / 0.05);

  /* Transitions */
  --transition-fast:   150ms ease;
  --transition-base:   200ms ease;
  --transition-slow:   300ms ease;
  --transition-spring: 300ms cubic-bezier(0.34, 1.56, 0.64, 1);

  /* Layout */
  --navbar-height: 64px;
  --content-max-w: 1100px;
  --page-padding:  clamp(1rem, 5vw, 2.5rem);
}


/* ------------------------------------------------------------
   2. GOOGLE FONTS IMPORT
   ------------------------------------------------------------ */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Lora:ital,wght@0,400;0,600;1,400;1,600&display=swap');


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

html {
  font-size: 16px;
  scroll-padding-top: calc(var(--navbar-height) + 1.5rem);
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  font-weight: var(--fw-normal);
  line-height: var(--lh-relaxed);
  color: var(--color-text-primary);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

img, picture, video, canvas, svg {
  display: block;
  max-width: 100%;
}

input, button, textarea, select {
  font: inherit;
}

p, h1, h2, h3, h4, h5, h6 {
  overflow-wrap: break-word;
}

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

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

ul, ol {
  list-style: none;
}

/* Selection */
::selection {
  background-color: var(--color-accent);
  color: var(--color-text-inverse);
}


/* ------------------------------------------------------------
   4. NAVBAR
   ------------------------------------------------------------ */
.navbar {
  position: sticky;
  top: 0;
  left: 0;
  right: 0;
  height: var(--navbar-height);
  background-color: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px) saturate(180%);
  -webkit-backdrop-filter: blur(12px) saturate(180%);
  border-bottom: 1px solid var(--color-border);
  z-index: 1000;
  transition: box-shadow var(--transition-base), background-color var(--transition-base);
}

.navbar.scrolled {
  box-shadow: var(--shadow-md);
  background-color: rgba(255, 255, 255, 0.97);
}

.navbar-inner {
  max-width: var(--content-max-w);
  margin: 0 auto;
  padding: 0 var(--page-padding);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-8);
}

.navbar-brand {
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: var(--fw-semibold);
  color: var(--color-heading);
  letter-spacing: -0.01em;
  white-space: nowrap;
  transition: color var(--transition-fast), opacity var(--transition-fast);
  flex-shrink: 0;
}

.navbar-brand:hover {
  color: var(--color-accent);
  opacity: 0.9;
}

.navbar-brand span {
  color: var(--color-accent);
}

/* Nav Links */
.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  flex-wrap: nowrap;
}

.nav-link {
  font-size: var(--text-sm);
  font-weight: var(--fw-medium);
  color: var(--color-text-secondary);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  letter-spacing: 0.01em;
  transition: color var(--transition-fast), background-color var(--transition-fast);
  white-space: nowrap;
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 4px;
  left: 50%;
  transform: translateX(-50%) scaleX(0);
  width: calc(100% - var(--space-6));
  height: 2px;
  background-color: var(--color-accent);
  border-radius: var(--radius-full);
  transition: transform var(--transition-base);
}

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

.nav-link:hover::after,
.nav-link.active::after {
  transform: translateX(-50%) scaleX(1);
}

.nav-link.active {
  color: var(--color-accent);
  font-weight: var(--fw-semibold);
}

/* Hamburger (mobile) */
.nav-hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  padding: var(--space-2);
  background: none;
  border: none;
  cursor: pointer;
  border-radius: var(--radius-md);
  transition: background-color var(--transition-fast);
}

.nav-hamburger:hover {
  background-color: var(--color-bg-muted);
}

.nav-hamburger span {
  display: block;
  width: 20px;
  height: 2px;
  background-color: var(--color-text-secondary);
  border-radius: var(--radius-full);
  transition: transform var(--transition-base), opacity var(--transition-base);
}

.nav-hamburger.open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-hamburger.open span:nth-child(2) {
  opacity: 0;
  transform: scaleX(0);
}

.nav-hamburger.open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Mobile Nav Drawer */
.nav-mobile-menu {
  display: none;
  position: fixed;
  top: var(--navbar-height);
  left: 0;
  right: 0;
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-4) var(--page-padding);
  flex-direction: column;
  gap: var(--space-1);
  z-index: 999;
  box-shadow: var(--shadow-lg);
  animation: slideDown var(--transition-base) ease forwards;
}

.nav-mobile-menu.open {
  display: flex;
}

.nav-mobile-menu .nav-link {
  font-size: var(--text-base);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-lg);
}

@keyframes slideDown {
  from { opacity: 0; transform: translateY(-8px); }
  to   { opacity: 1; transform: translateY(0); }
}


/* ------------------------------------------------------------
   5. PAGE LAYOUT
   ------------------------------------------------------------ */
.page-wrapper {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.main-content {
  flex: 1;
  max-width: var(--content-max-w);
  margin: 0 auto;
  padding: 0 var(--page-padding);
  width: 100%;
}

.section-divider {
  border: none;
  height: 1px;
  background: linear-gradient(
    to right,
    transparent,
    var(--color-border) 20%,
    var(--color-border) 80%,
    transparent
  );
  margin: var(--space-16) 0;
}


/* ------------------------------------------------------------
   6. HERO SECTION
   ------------------------------------------------------------ */
.hero {
  padding: var(--space-20) var(--page-padding) var(--space-12);
  max-width: var(--content-max-w);
  margin: 0 auto;
  width: 100%;
  display: flex;
  align-items: center;
  gap: clamp(var(--space-8), 5vw, var(--space-16));
}

.hero-photo-wrapper {
  flex-shrink: 0;
  position: relative;
}

.hero-photo {
  width: 180px;
  height: 180px;
  border-radius: var(--radius-full);
  object-fit: cover;
  object-position: center top;
  border: 3px solid var(--color-border);
  box-shadow: var(--shadow-xl),
              0 0 0 6px var(--color-accent-light);
  transition: transform var(--transition-slow), box-shadow var(--transition-slow);
}

.hero-photo:hover {
  transform: scale(1.03);
  box-shadow: var(--shadow-xl),
              0 0 0 8px var(--color-accent-light);
}

/* Fallback avatar if no photo */
.hero-photo-placeholder {
  width: 180px;
  height: 180px;
  border-radius: var(--radius-full);
  background: linear-gradient(135deg, var(--color-accent-light) 0%, #dbeafe 100%);
  border: 3px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-heading);
  font-size: var(--text-4xl);
  font-weight: var(--fw-semibold);
  color: var(--color-accent);
  box-shadow: var(--shadow-xl), 0 0 0 6px var(--color-accent-light);
}

.hero-info {
  flex: 1;
  min-width: 0;
}

.hero-name {
  font-family: var(--font-heading);
  font-size: clamp(var(--text-3xl), 5vw, var(--text-4xl));
  font-weight: var(--fw-bold);
  color: var(--color-heading);
  line-height: var(--lh-tight);
  letter-spacing: -0.02em;
  margin-bottom: var(--space-2);
}

.hero-name-kr {
  font-family: var(--font-sans);
  font-size: var(--text-lg);
  font-weight: var(--fw-normal);
  color: var(--color-text-muted);
  margin-left: var(--space-3);
  letter-spacing: 0.02em;
}

.hero-title {
  font-size: var(--text-lg);
  font-weight: var(--fw-medium);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-1);
  line-height: var(--lh-snug);
}

.hero-affiliation {
  font-size: var(--text-base);
  color: var(--color-text-muted);
  margin-bottom: var(--space-6);
}

.hero-affiliation a {
  color: var(--color-text-secondary);
  font-weight: var(--fw-medium);
  border-bottom: 1px solid var(--color-border);
  transition: color var(--transition-fast), border-color var(--transition-fast);
}

.hero-affiliation a:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
}

/* Hero Links (email, GitHub, Scholar, etc.) */
.hero-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  align-items: center;
}

.hero-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  font-weight: var(--fw-medium);
  color: var(--color-text-secondary);
  padding: var(--space-2) var(--space-3);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  background-color: var(--color-surface);
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.hero-link:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
  background-color: var(--color-accent-light);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.hero-email {
  margin-bottom: var(--space-3);
  font-size: var(--text-sm);
  color: var(--color-text-primary);
  font-family: var(--font-mono);
  font-weight: var(--fw-medium);
}

.hero-email-label {
  color: var(--color-text-muted);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
}

.hero-link svg,
.hero-link img {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
}

.hero-link .hero-link-icon {
  font-size: 15px;
  line-height: 1;
}


/* ------------------------------------------------------------
   7. SECTION WRAPPERS
   ------------------------------------------------------------ */
.section {
  padding: var(--space-12) 0;
}

.section-header {
  margin-bottom: var(--space-8);
}

.section-title {
  font-family: var(--font-heading);
  font-size: var(--text-2xl);
  font-weight: var(--fw-semibold);
  color: var(--color-heading);
  line-height: var(--lh-tight);
  letter-spacing: -0.01em;
  padding-bottom: var(--space-3);
  border-bottom: 2px solid var(--color-accent);
  display: inline-block;
}

.section-subtitle {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-top: var(--space-2);
}

/* About section text */
.about-text {
  font-size: var(--text-base);
  line-height: var(--lh-loose);
  color: var(--color-text-secondary);
  max-width: 72ch;
}

.about-text p + p {
  margin-top: var(--space-4);
}

.about-text strong {
  color: var(--color-text-primary);
  font-weight: var(--fw-semibold);
}

/* Research Interests */
.interests-label {
  margin-top: var(--space-5);
  margin-bottom: var(--space-1);
  font-size: var(--text-sm);
  font-weight: var(--fw-semibold);
  color: var(--color-text-secondary);
  letter-spacing: 0.02em;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: var(--space-4);
}

.tag {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: var(--fw-medium);
  color: var(--color-accent-dark);
  background-color: var(--color-accent-light);
  border: 1px solid var(--badge-journal-border);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
  letter-spacing: 0.01em;
}

.tag:hover {
  background-color: var(--color-accent);
  color: var(--color-text-inverse);
  border-color: var(--color-accent);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}


/* ------------------------------------------------------------
   8. PUBLICATION FILTERS & GROUP TITLES
   ------------------------------------------------------------ */
.pub-filters {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin: var(--space-6) 0 var(--space-4);
}

.pub-filter {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: var(--fw-bold);
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: var(--space-2) var(--space-4);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  background-color: var(--color-surface);
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.pub-filter:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background-color: var(--color-accent-light);
}

.pub-filter.active {
  background-color: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-text-inverse);
}

.filter-count {
  font-size: 0.65rem;
  opacity: 0.8;
}

.pub-group-title {
  margin: 2rem 0 1rem;
  font-size: 1.05rem;
  font-weight: var(--fw-semibold);
  color: var(--color-accent);
  letter-spacing: -0.01em;
}

.pub-group-count {
  font-weight: var(--fw-normal);
  color: var(--color-text-muted);
  font-size: 0.95em;
}

/* ------------------------------------------------------------
   8b. PUBLICATION CARDS
   ------------------------------------------------------------ */
.pub-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.pub-card {
  display: flex;
  gap: var(--space-5);
  padding: var(--space-5) var(--space-6);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.pub-card::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background-color: transparent;
  transition: background-color var(--transition-base);
  border-radius: var(--radius-sm) 0 0 var(--radius-sm);
}

.pub-card:hover {
  border-color: var(--color-accent);
  box-shadow: var(--shadow-md);
  transform: translateY(-1px);
  background-color: var(--color-surface-hover);
}

.pub-card:hover::before {
  background-color: var(--color-accent);
}

/* Publication Number */
.pub-number {
  flex-shrink: 0;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: var(--fw-bold);
  color: var(--color-text-muted);
  background-color: var(--color-bg-muted);
  width: 28px;
  height: 28px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-top: 2px;
  flex-shrink: 0;
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.pub-card:hover .pub-number {
  background-color: var(--color-accent-light);
  color: var(--color-accent-dark);
}

.pub-body {
  flex: 1;
  min-width: 0;
}

.pub-top-row {
  display: flex;
  align-items: flex-start;
  gap: var(--space-2);
  flex-wrap: wrap;
  margin-bottom: var(--space-2);
}

/* Venue Badge */
.pub-badge {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: var(--fw-bold);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 2px var(--space-2);
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  flex-shrink: 0;
  margin-top: 2px;
}

.pub-badge.journal {
  background-color: var(--badge-journal-bg);
  color: var(--badge-journal-text);
  border-color: var(--badge-journal-border);
}

.pub-badge.conference {
  background-color: var(--badge-conf-bg);
  color: var(--badge-conf-text);
  border-color: var(--badge-conf-border);
}

.pub-badge.workshop {
  background-color: var(--badge-workshop-bg);
  color: var(--badge-workshop-text);
  border-color: var(--badge-workshop-border);
}

.pub-badge.domestic {
  background-color: var(--badge-domestic-bg);
  color: var(--badge-domestic-text);
  border-color: var(--badge-domestic-border);
}

.pub-badge.preprint {
  background-color: var(--badge-preprint-bg);
  color: var(--badge-preprint-text);
  border-color: var(--badge-preprint-border);
}

/* Publication Title */
.pub-title {
  font-size: var(--text-base);
  font-weight: var(--fw-semibold);
  color: var(--color-text-primary);
  line-height: var(--lh-snug);
  margin-bottom: var(--space-1);
  transition: color var(--transition-fast);
}

.pub-card:hover .pub-title {
  color: var(--color-accent-dark);
}

/* Authors */
.pub-authors {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: var(--lh-normal);
  margin-bottom: var(--space-1);
}

.pub-highlight {
  font-weight: var(--fw-bold);
  color: var(--color-text-primary);
  text-decoration: underline;
  text-decoration-color: var(--color-accent);
  text-underline-offset: 2px;
}

/* Venue / Journal name */
.pub-venue {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  font-style: italic;
  margin-bottom: var(--space-3);
  line-height: var(--lh-normal);
}

.pub-venue strong {
  font-style: normal;
  font-weight: var(--fw-semibold);
  color: var(--color-text-primary);
}

/* Publication Meta (year, etc.) */
.pub-meta {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-bottom: var(--space-2);
}

/* Publication action links */
.pub-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: var(--space-2);
}

.btn-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: var(--fw-bold);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: 3px var(--space-3);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background-color: var(--color-bg-muted);
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.btn-link:hover {
  background-color: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-text-inverse);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}

.btn-link.btn-pdf:hover   { background-color: #dc2626; border-color: #dc2626; }
.btn-link.btn-code:hover  { background-color: #16a34a; border-color: #16a34a; }
.btn-link.btn-arxiv:hover { background-color: #b45309; border-color: #b45309; }
.btn-link.btn-demo:hover  { background-color: #7c3aed; border-color: #7c3aed; }
.btn-link.btn-slides:hover{ background-color: #0891b2; border-color: #0891b2; }

.btn-link svg {
  width: 11px;
  height: 11px;
}


/* ------------------------------------------------------------
   9. TIMELINE (Experience & Education)
   ------------------------------------------------------------ */
.timeline {
  position: relative;
  padding-left: var(--space-8);
}

.timeline::before {
  content: '';
  position: absolute;
  left: 11px;
  top: 4px;
  bottom: 4px;
  width: 2px;
  background: linear-gradient(
    to bottom,
    var(--color-accent),
    var(--color-border) 80%,
    transparent
  );
}

.timeline-item {
  position: relative;
  padding-bottom: var(--space-8);
}

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

.timeline-dot {
  position: absolute;
  left: calc(-1 * var(--space-8) + 6px);
  top: 4px;
  width: 14px;
  height: 14px;
  border-radius: var(--radius-full);
  background-color: var(--color-surface);
  border: 2px solid var(--color-accent);
  transition: all var(--transition-base);
  z-index: 1;
}

.timeline-item:hover .timeline-dot {
  background-color: var(--color-accent);
  transform: scale(1.2);
  box-shadow: 0 0 0 3px var(--color-accent-light);
}

.timeline-content {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-5) var(--space-6);
  transition: all var(--transition-base);
}

.timeline-item:hover .timeline-content {
  border-color: var(--color-accent);
  box-shadow: var(--shadow-md);
  transform: translateX(2px);
}

.timeline-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: var(--space-4);
  flex-wrap: wrap;
  margin-bottom: var(--space-1);
}

.timeline-date {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: var(--fw-medium);
  color: var(--color-accent);
  background-color: var(--color-accent-light);
  padding: 2px var(--space-3);
  border-radius: var(--radius-full);
  white-space: nowrap;
  flex-shrink: 0;
}

.timeline-title {
  font-size: var(--text-base);
  font-weight: var(--fw-semibold);
  color: var(--color-text-primary);
  line-height: var(--lh-snug);
}

.timeline-subtitle {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin-top: var(--space-1);
  font-style: italic;
}

.timeline-desc {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: var(--lh-relaxed);
  margin-top: var(--space-3);
}

.timeline-desc ul {
  list-style: disc;
  padding-left: var(--space-5);
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}


/* ------------------------------------------------------------
   10. AWARDS LIST
   ------------------------------------------------------------ */
.award-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.award-item {
  display: flex;
  align-items: flex-start;
  gap: var(--space-4);
  padding: var(--space-4) var(--space-5);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  transition: all var(--transition-base);
}

.award-item:hover {
  border-color: var(--color-accent);
  box-shadow: var(--shadow-sm);
  transform: translateX(2px);
}

.award-icon {
  font-size: var(--text-xl);
  flex-shrink: 0;
  line-height: 1;
  margin-top: 2px;
}

.award-body {
  flex: 1;
  min-width: 0;
}

.award-title {
  font-size: var(--text-sm);
  font-weight: var(--fw-semibold);
  color: var(--color-text-primary);
  line-height: var(--lh-snug);
  margin-bottom: var(--space-1);
}

.award-meta {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-family: var(--font-mono);
}

.award-year {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: var(--fw-bold);
  color: var(--color-accent);
  background-color: var(--color-accent-light);
  padding: 2px var(--space-2);
  border-radius: var(--radius-sm);
  white-space: nowrap;
  flex-shrink: 0;
  align-self: flex-start;
}

.award-desc {
  font-size: var(--text-sm);
  font-weight: var(--fw-medium);
  color: var(--color-text-primary);
  line-height: var(--lh-snug);
  flex: 1;
}


/* ------------------------------------------------------------
   11. PEER REVIEW LIST
   ------------------------------------------------------------ */
.review-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.review-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  border: 1px solid transparent;
  transition: all var(--transition-fast);
}

.review-item:hover {
  background-color: var(--color-bg-soft);
  border-color: var(--color-border);
  color: var(--color-text-primary);
}

.review-item::before {
  content: '';
  display: block;
  width: 6px;
  height: 6px;
  border-radius: var(--radius-full);
  background-color: var(--color-accent);
  flex-shrink: 0;
}

.review-item-name {
  flex: 1;
  font-weight: var(--fw-medium);
}

.review-item-count {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  white-space: nowrap;
}


/* ------------------------------------------------------------
   12. TWO-COLUMN GRID LAYOUT
   ------------------------------------------------------------ */
.two-col-grid {
  display: grid !important;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-8);
  align-items: start;
}

.review-list.two-col-grid {
  row-gap: 0;
  column-gap: var(--space-4);
}

/* ------------------------------------------------------------
   PRESENTATIONS
   ------------------------------------------------------------ */
.presentation-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  margin-top: var(--space-4);
}

.presentation-item {
  display: flex;
  align-items: flex-start;
  gap: var(--space-4);
  padding: var(--space-4) var(--space-5);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  background: var(--color-surface);
  transition: all var(--transition-base);
}

.presentation-item:hover {
  border-color: var(--color-accent);
  box-shadow: var(--shadow-sm);
  transform: translateX(2px);
}

.presentation-year {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: var(--fw-bold);
  color: var(--color-accent);
  background-color: var(--color-accent-light);
  padding: 2px var(--space-2);
  border-radius: var(--radius-sm);
  white-space: nowrap;
  flex-shrink: 0;
  align-self: flex-start;
  margin-top: 2px;
}

.presentation-body {
  flex: 1;
  min-width: 0;
}

.presentation-title {
  font-size: var(--text-sm);
  font-weight: var(--fw-semibold);
  color: var(--color-text-primary);
  line-height: var(--lh-snug);
}

.presentation-venue {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  font-style: italic;
  margin-top: var(--space-1);
}

/* ------------------------------------------------------------
   CV VIEWER
   ------------------------------------------------------------ */
.cv-toolbar {
  display: flex;
  justify-content: flex-end;
  margin-bottom: var(--space-3);
}

.btn-cv-download {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  font-weight: var(--fw-medium);
  color: var(--color-text-inverse);
  background-color: var(--color-accent);
  border: 1px solid var(--color-accent);
  border-radius: var(--radius-full);
  padding: var(--space-2) var(--space-5);
  transition: all var(--transition-fast);
}

.btn-cv-download:hover {
  background-color: var(--color-accent-dark);
  border-color: var(--color-accent-dark);
  color: var(--color-text-inverse);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.cv-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-4);
  gap: var(--space-4);
}

.cv-page-nav {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.cv-nav-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  background: var(--color-surface);
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  font-size: var(--text-xs);
}

.cv-nav-btn:hover:not(:disabled) {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: var(--color-accent-light);
}

.cv-nav-btn:disabled {
  opacity: 0.35;
  cursor: default;
}

.cv-page-info {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  min-width: 60px;
  text-align: center;
}

.cv-viewer {
  width: 100%;
  height: 80vh;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

.cv-viewer object,
.cv-viewer embed {
  display: block;
  border-radius: var(--radius-xl);
}

@media (max-width: 640px) {
  .two-col-grid {
    grid-template-columns: 1fr;
    gap: var(--space-12);
  }
}


/* ------------------------------------------------------------
   13. FOOTER
   ------------------------------------------------------------ */
.footer {
  margin-top: auto;
  padding: var(--space-12) var(--page-padding);
  border-top: 1px solid var(--color-border);
  background-color: var(--color-bg-soft);
}

.footer-inner {
  max-width: var(--content-max-w);
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-3);
  text-align: center;
}

.footer-name {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--fw-semibold);
  color: var(--color-heading);
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-4);
}

.footer-link {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  transition: color var(--transition-fast);
}

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

.footer-copy {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-family: var(--font-mono);
}

.footer-copy a {
  color: var(--color-text-muted);
  border-bottom: 1px solid var(--color-border);
  transition: color var(--transition-fast), border-color var(--transition-fast);
}

.footer-copy a:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
}


/* ------------------------------------------------------------
   14. UTILITY CLASSES
   ------------------------------------------------------------ */

/* Visibility */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Text utilities */
.text-accent  { color: var(--color-accent); }
.text-muted   { color: var(--color-text-muted); }
.text-sm      { font-size: var(--text-sm); }
.text-xs      { font-size: var(--text-xs); }
.font-mono    { font-family: var(--font-mono); }
.font-heading { font-family: var(--font-heading); }

/* Layout utilities */
.flex         { display: flex; }
.flex-wrap    { flex-wrap: wrap; }
.items-center { align-items: center; }
.gap-2        { gap: var(--space-2); }
.gap-3        { gap: var(--space-3); }
.gap-4        { gap: var(--space-4); }
.mt-2         { margin-top: var(--space-2); }
.mt-4         { margin-top: var(--space-4); }
.mt-6         { margin-top: var(--space-6); }
.mt-8         { margin-top: var(--space-8); }
.mb-4         { margin-bottom: var(--space-4); }
.mb-6         { margin-bottom: var(--space-6); }

/* Anchor offset for sticky nav */
.anchor-offset {
  scroll-margin-top: calc(var(--navbar-height) + 1.5rem);
}


/* ------------------------------------------------------------
   15. RESPONSIVE BREAKPOINTS
   ------------------------------------------------------------ */

/* Tablet: 768px */
@media (max-width: 768px) {
  :root {
    --navbar-height: 56px;
  }

  .nav-links {
    display: none;
  }

  .nav-hamburger {
    display: flex;
  }

  .hero {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-6);
    padding: var(--space-12) var(--page-padding) var(--space-8);
    text-align: left;
  }

  .hero-photo,
  .hero-photo-placeholder {
    width: 140px;
    height: 140px;
  }

  .pub-card {
    flex-direction: column;
    gap: var(--space-3);
  }

  .pub-number {
    display: none;
  }

  .timeline {
    padding-left: var(--space-6);
  }
}

/* Mobile: 480px */
@media (max-width: 480px) {
  .hero-name {
    font-size: var(--text-2xl);
  }

  .hero-links {
    gap: var(--space-2);
  }

  .hero-link {
    font-size: 0.75rem;
    padding: var(--space-1) var(--space-2);
  }

  .section-title {
    font-size: var(--text-xl);
  }

  .timeline-header {
    flex-direction: column;
    gap: var(--space-2);
  }

  .award-item {
    flex-wrap: wrap;
  }

  .pub-card {
    padding: var(--space-4);
  }

  .timeline-content {
    padding: var(--space-4);
  }
}


/* ------------------------------------------------------------
   16. PAGE SLIDE TRANSITION
   ------------------------------------------------------------ */
body {
  overflow-x: hidden;
}

/* ------------------------------------------------------------
   17. SCROLL & FOCUS ACCESSIBILITY
   ------------------------------------------------------------ */

/* Focus ring */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  html {
    scroll-behavior: auto;
  }
}


/* ------------------------------------------------------------
   18. SCROLLBAR STYLING (Webkit)
   ------------------------------------------------------------ */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: var(--color-bg-soft);
}

::-webkit-scrollbar-thumb {
  background: var(--color-border-strong);
  border-radius: var(--radius-full);
  border: 2px solid var(--color-bg-soft);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-text-muted);
}


/* ------------------------------------------------------------
   18. DARK MODE (prefers-color-scheme — optional / future)
   ------------------------------------------------------------ */
/*
@media (prefers-color-scheme: dark) {
  :root {
    --color-bg:            #0f172a;
    --color-bg-soft:       #1e293b;
    --color-bg-muted:      #334155;
    --color-surface:       #1e293b;
    --color-surface-hover: #253450;
    --color-border:        #334155;
    --color-border-strong: #475569;
    --color-text-primary:  #f1f5f9;
    --color-text-secondary:#cbd5e1;
    --color-text-muted:    #64748b;
    --color-heading:       #e2e8f0;
  }
}
*/


/* ------------------------------------------------------------
   19. SECTION-SPECIFIC REFINEMENTS
   ------------------------------------------------------------ */

/* News / Updates section */
.news-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.news-item {
  display: flex;
  gap: var(--space-4);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: var(--lh-normal);
  padding-bottom: var(--space-3);
  border-bottom: 1px solid var(--color-border);
}

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

.news-date {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-accent);
  white-space: nowrap;
  flex-shrink: 0;
  padding-top: 2px;
  min-width: 80px;
}

/* Contact info items */
.contact-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.contact-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
}

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

.contact-item a:hover {
  color: var(--color-accent-hover);
  text-decoration: underline;
}

/* Inline note / annotation under publications */
.pub-note {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-style: italic;
  margin-top: var(--space-1);
}

/* Year group separator in publication list */
.pub-year-group {
  margin-top: var(--space-8);
}

.pub-year-heading {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: var(--fw-bold);
  color: var(--color-text-muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-2);
  border-bottom: 1px dashed var(--color-border);
}

/* Stats bar (for quick numbers in hero or about) */
.stats-bar {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-6);
  padding: var(--space-5) 0;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  margin: var(--space-8) 0;
}

.stat-item {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.stat-value {
  font-family: var(--font-heading);
  font-size: var(--text-2xl);
  font-weight: var(--fw-bold);
  color: var(--color-accent);
  line-height: 1;
}

.stat-label {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}