/* =====================================================
   Academic Portfolio – Samson Tilahun Moges
   Arctic Aurora Design System
   ===================================================== */

/* ---------- CSS Custom Properties ---------- */
:root,
[data-theme="dark"] {
  --color-bg:            #050c1a;
  --color-bg-alt:        #08121f;
  --color-surface:       #0e1d32;
  --color-surface-2:     #152440;
  --color-surface-3:     #1a2d4e;

  --color-primary:       #00c8b4;
  --color-primary-dark:  #00a898;
  --color-primary-light: rgba(0, 200, 180, 0.12);

  --color-accent:        #f0a500;
  --color-accent-dark:   #c98a00;
  --color-accent-light:  rgba(240, 165, 0, 0.12);

  --color-purple:        #8b5cf6;
  --color-purple-light:  rgba(139, 92, 246, 0.12);

  --color-text:          #e2ecf8;
  --color-text-muted:    #7a9abd;
  --color-text-faint:    #3d5a78;

  --color-border:        rgba(255, 255, 255, 0.07);
  --color-border-strong: rgba(255, 255, 255, 0.13);
  --color-card-bg:       rgba(14, 29, 50, 0.85);

  /* publication type colours */
  --color-q1:            #00c8b4;
  --color-q1-bg:         rgba(0, 200, 180, 0.15);
  --color-q2:            #60a5fa;
  --color-q2-bg:         rgba(96, 165, 250, 0.15);
  --color-thesis:        #c084fc;
  --color-thesis-bg:     rgba(192, 132, 252, 0.15);
  --color-conf:          #f0a500;
  --color-conf-bg:       rgba(240, 165, 0, 0.15);
  --color-preprint:      #f87171;
  --color-preprint-bg:   rgba(248, 113, 113, 0.15);

  --nav-height:          68px;
  --progress-color:      var(--color-primary);
}

[data-theme="light"] {
  --color-bg:            #f8fbff;
  --color-bg-alt:        #eef4fc;
  --color-surface:       #ffffff;
  --color-surface-2:     #f0f6ff;
  --color-surface-3:     #e8f1fc;

  --color-primary:       #007d72;
  --color-primary-dark:  #006059;
  --color-primary-light: rgba(0, 125, 114, 0.10);

  --color-accent:        #b07400;
  --color-accent-dark:   #8a5c00;
  --color-accent-light:  rgba(176, 116, 0, 0.10);

  --color-purple:        #6d28d9;
  --color-purple-light:  rgba(109, 40, 217, 0.10);

  --color-text:          #0d1e38;
  --color-text-muted:    #426080;
  --color-text-faint:    #8ca8c0;

  --color-border:        rgba(0, 0, 0, 0.08);
  --color-border-strong: rgba(0, 0, 0, 0.14);
  --color-card-bg:       #ffffff;

  --color-q1:            #006b60;
  --color-q1-bg:         rgba(0, 107, 96, 0.10);
  --color-q2:            #1d4ed8;
  --color-q2-bg:         rgba(29, 78, 216, 0.10);
  --color-thesis:        #7c3aed;
  --color-thesis-bg:     rgba(124, 58, 237, 0.10);
  --color-conf:          #92400e;
  --color-conf-bg:       rgba(146, 64, 14, 0.10);
  --color-preprint:      #be185d;
  --color-preprint-bg:   rgba(190, 24, 93, 0.10);
}

/* ---------- Fonts ---------- */
:root {
  --font-display: 'Playfair Display', Georgia, 'Times New Roman', serif;
  --font-sans:    'Source Sans 3', 'Helvetica Neue', system-ui, sans-serif;
  --font-mono:    'JetBrains Mono', 'Fira Code', Consolas, monospace;

  --radius-xs:   4px;
  --radius-sm:   8px;
  --radius-md:   14px;
  --radius-lg:   22px;
  --radius-xl:   32px;
  --radius-full: 9999px;

  --shadow-sm:  0 2px 8px rgba(0,0,0,0.12);
  --shadow-md:  0 8px 32px rgba(0,0,0,0.18), 0 2px 8px rgba(0,0,0,0.12);
  --shadow-lg:  0 20px 60px rgba(0,0,0,0.28), 0 6px 20px rgba(0,0,0,0.16);
  --shadow-glow: 0 0 40px rgba(0, 200, 180, 0.18);

  --transition: 0.22s ease;
  --transition-slow: 0.4s ease;
}

[data-theme="light"] {
  --shadow-sm:  0 2px 8px rgba(0,0,0,0.06);
  --shadow-md:  0 8px 32px rgba(0,0,0,0.10), 0 2px 8px rgba(0,0,0,0.06);
  --shadow-lg:  0 20px 60px rgba(0,0,0,0.12), 0 6px 20px rgba(0,0,0,0.08);
  --shadow-glow: 0 0 40px rgba(0, 125, 114, 0.15);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background var(--transition-slow), color var(--transition-slow);
  overflow-x: hidden;
}

img { max-width: 100%; display: block; }
a  { color: var(--color-primary); text-decoration: none; }
a:hover { text-decoration: underline; }
button { cursor: pointer; font-family: var(--font-sans); }

/* ---------- Scroll Progress Bar ---------- */
#scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0%;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
  z-index: 9999;
  transition: width 0.1s linear;
  border-radius: 0 var(--radius-full) var(--radius-full) 0;
}

/* ---------- Utilities ---------- */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 28px;
}

.inline-link {
  color: var(--color-primary);
  font-weight: 500;
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition);
}
.inline-link:hover { text-decoration: none; border-bottom-color: var(--color-primary); }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 10px 22px;
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 600;
  font-family: var(--font-sans);
  cursor: pointer;
  transition: all var(--transition);
  border: 2px solid transparent;
  text-decoration: none !important;
  white-space: nowrap;
  letter-spacing: 0.01em;
}
.btn:hover { transform: translateY(-2px); text-decoration: none; }
.btn:active { transform: translateY(0); }

.btn-primary {
  background: var(--color-primary);
  color: #050c1a;
  border-color: var(--color-primary);
}
[data-theme="light"] .btn-primary { color: #ffffff; }
.btn-primary:hover { background: var(--color-primary-dark); border-color: var(--color-primary-dark); box-shadow: 0 4px 20px rgba(0, 200, 180, 0.35); }

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}
.btn-outline:hover { background: var(--color-primary-light); }

.btn-ghost {
  background: var(--color-surface-2);
  color: var(--color-text-muted);
  border-color: var(--color-border);
}
.btn-ghost:hover { background: var(--color-surface-3); color: var(--color-text); }

.btn-accent {
  background: var(--color-accent);
  color: #050c1a;
  border-color: var(--color-accent);
}
[data-theme="light"] .btn-accent { color: #ffffff; }
.btn-accent:hover { background: var(--color-accent-dark); border-color: var(--color-accent-dark); }

.btn-sm {
  padding: 6px 14px;
  font-size: 0.8rem;
}

.btn-large {
  padding: 13px 30px;
  font-size: 0.95rem;
}

/* ---------- Sections ---------- */
.section {
  padding: 100px 0;
}
.section-alt {
  background: var(--color-bg-alt);
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 3vw, 2.6rem);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 12px;
  letter-spacing: -0.01em;
  line-height: 1.2;
}
.section-title::after {
  content: '';
  display: block;
  width: 48px;
  height: 3px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
  margin-top: 12px;
  border-radius: var(--radius-full);
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  margin-bottom: 56px;
  max-width: 640px;
  line-height: 1.65;
}

.subsection-title {
  font-family: var(--font-display);
  font-size: 1.4rem;
  font-weight: 600;
  color: var(--color-text);
  margin: 64px 0 28px;
}

/* ---------- Fade-in animation ---------- */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.55s ease, transform 0.55s ease;
}
.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* =====================================================
   NAVBAR
   ===================================================== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--nav-height);
  transition: background var(--transition), box-shadow var(--transition), backdrop-filter var(--transition);
}
.navbar.scrolled {
  background: rgba(5, 12, 26, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: 0 1px 0 var(--color-border), 0 4px 24px rgba(0,0,0,0.3);
}
[data-theme="light"] .navbar.scrolled {
  background: rgba(248, 251, 255, 0.88);
  box-shadow: 0 1px 0 var(--color-border), 0 4px 24px rgba(0,0,0,0.08);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 28px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.nav-brand {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
  text-decoration: none;
  flex-shrink: 0;
}
.nav-brand:hover { text-decoration: none; }
.nav-brand-name {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: -0.01em;
}
.nav-brand-sub {
  font-size: 0.7rem;
  font-weight: 500;
  color: var(--color-primary);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-links {
  display: flex;
  align-items: center;
  list-style: none;
  gap: 2px;
}
.nav-links a {
  display: block;
  padding: 6px 12px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-muted);
  border-radius: var(--radius-sm);
  transition: color var(--transition), background var(--transition);
  text-decoration: none;
  letter-spacing: 0.01em;
}
.nav-links a:hover,
.nav-links a.active {
  color: var(--color-primary);
  background: var(--color-primary-light);
  text-decoration: none;
}

/* Theme Toggle */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
  background: var(--color-surface-2);
  color: var(--color-text-muted);
  transition: all var(--transition);
  flex-shrink: 0;
}
.theme-toggle:hover {
  background: var(--color-surface-3);
  color: var(--color-primary);
  border-color: var(--color-primary);
}
.icon-sun  { display: none; }
.icon-moon { display: block; }
[data-theme="light"] .icon-sun  { display: block; }
[data-theme="light"] .icon-moon { display: none; }

/* Mobile nav toggle */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: space-between;
  width: 24px;
  height: 18px;
  background: transparent;
  border: none;
  padding: 0;
  cursor: pointer;
}
.nav-toggle span {
  display: block;
  height: 2px;
  background: var(--color-text-muted);
  border-radius: 2px;
  transition: all var(--transition);
}

/* =====================================================
   HERO
   ===================================================== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  background: linear-gradient(180deg, #020913 0%, #050c1a 30%, #070f20 60%, #0a1628 100%);
  padding-top: var(--nav-height);
}

[data-theme="light"] .hero {
  background: linear-gradient(180deg, #e8f1fd 0%, #d8eafa 30%, #cee3f8 60%, #c5dcf5 100%);
}

/* Aurora Background */
.hero-aurora {
  position: absolute;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
}
.aurora-1, .aurora-2, .aurora-3 {
  position: absolute;
  inset: -60%;
  border-radius: 50%;
}
.aurora-1 {
  background: radial-gradient(
    ellipse 100% 50% at 25% 55%,
    rgba(0, 200, 180, 0.22) 0%,
    rgba(0, 150, 140, 0.08) 45%,
    transparent 70%
  );
  animation: auroraFloat1 20s ease-in-out infinite alternate;
}
.aurora-2 {
  background: radial-gradient(
    ellipse 80% 60% at 70% 45%,
    rgba(100, 30, 200, 0.18) 0%,
    rgba(80, 20, 160, 0.07) 45%,
    transparent 70%
  );
  animation: auroraFloat2 26s ease-in-out infinite alternate;
}
.aurora-3 {
  background: radial-gradient(
    ellipse 70% 80% at 50% 85%,
    rgba(20, 60, 180, 0.15) 0%,
    transparent 60%
  );
  animation: auroraFloat3 16s ease-in-out infinite alternate;
}

[data-theme="light"] .aurora-1 {
  background: radial-gradient(
    ellipse 100% 50% at 25% 55%,
    rgba(0, 160, 145, 0.20) 0%,
    rgba(0, 120, 110, 0.06) 45%,
    transparent 70%
  );
}
[data-theme="light"] .aurora-2 {
  background: radial-gradient(
    ellipse 80% 60% at 70% 45%,
    rgba(90, 30, 180, 0.13) 0%,
    transparent 70%
  );
}
[data-theme="light"] .aurora-3 {
  background: radial-gradient(
    ellipse 70% 80% at 50% 85%,
    rgba(10, 50, 160, 0.12) 0%,
    transparent 60%
  );
}

@keyframes auroraFloat1 {
  from { transform: translate(0, 0) scale(1); }
  to   { transform: translate(8%, -6%) scale(1.2); }
}
@keyframes auroraFloat2 {
  from { transform: translate(0, 0) scale(1) rotate(0deg); }
  to   { transform: translate(-7%, 9%) scale(1.18) rotate(-6deg); }
}
@keyframes auroraFloat3 {
  from { transform: translate(0, 0) scale(1); }
  to   { transform: translate(5%, 4%) scale(1.12); }
}

/* Hero star field */
.hero-stars {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    radial-gradient(1px 1px at 10% 15%, rgba(255,255,255,0.5) 0%, transparent 100%),
    radial-gradient(1px 1px at 30% 8%, rgba(255,255,255,0.4) 0%, transparent 100%),
    radial-gradient(1px 1px at 55% 22%, rgba(255,255,255,0.6) 0%, transparent 100%),
    radial-gradient(1px 1px at 75% 5%, rgba(255,255,255,0.5) 0%, transparent 100%),
    radial-gradient(1px 1px at 88% 18%, rgba(255,255,255,0.4) 0%, transparent 100%),
    radial-gradient(1px 1px at 20% 40%, rgba(255,255,255,0.3) 0%, transparent 100%),
    radial-gradient(1px 1px at 65% 35%, rgba(255,255,255,0.5) 0%, transparent 100%),
    radial-gradient(1px 1px at 90% 45%, rgba(255,255,255,0.4) 0%, transparent 100%),
    radial-gradient(1.5px 1.5px at 40% 60%, rgba(255,255,255,0.35) 0%, transparent 100%),
    radial-gradient(1px 1px at 80% 72%, rgba(255,255,255,0.45) 0%, transparent 100%),
    radial-gradient(1px 1px at 15% 78%, rgba(255,255,255,0.3) 0%, transparent 100%),
    radial-gradient(1px 1px at 50% 88%, rgba(255,255,255,0.35) 0%, transparent 100%);
}
[data-theme="light"] .hero-stars { display: none; }

.hero-content {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  gap: 64px;
  max-width: 1100px;
  width: 100%;
  padding: 0 28px;
  padding-bottom: 40px;
}

.hero-avatar {
  position: relative;
  flex-shrink: 0;
}
.avatar-img {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--color-primary);
  box-shadow: 0 0 0 8px rgba(0, 200, 180, 0.10), var(--shadow-lg);
  transition: transform var(--transition), box-shadow var(--transition);
}
.avatar-img:hover {
  transform: scale(1.03);
  box-shadow: 0 0 0 10px rgba(0, 200, 180, 0.15), var(--shadow-glow);
}
.avatar-ring {
  position: absolute;
  inset: -12px;
  border-radius: 50%;
  border: 1px solid rgba(0, 200, 180, 0.25);
  animation: pulse 3s ease-in-out infinite;
}
@keyframes pulse {
  0%, 100% { transform: scale(1); opacity: 0.5; }
  50%       { transform: scale(1.05); opacity: 0.2; }
}

.hero-text {
  flex: 1;
  min-width: 0;
}
.hero-pre {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.82rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: 14px;
}
.hero-pre::before {
  content: '';
  display: inline-block;
  width: 28px;
  height: 2px;
  background: var(--color-primary);
  border-radius: 2px;
}

.hero-name {
  font-family: var(--font-display);
  font-size: clamp(2.4rem, 5vw, 4rem);
  font-weight: 700;
  line-height: 1.1;
  color: var(--color-text);
  margin-bottom: 18px;
  letter-spacing: -0.02em;
}
.hero-name-accent {
  color: var(--color-primary);
}
[data-theme="light"] .hero-name { color: #0d1e38; }

.hero-affiliation {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  font-size: 0.95rem;
  color: var(--color-text-muted);
  margin-bottom: 24px;
  line-height: 1.5;
}
.hero-affiliation svg {
  flex-shrink: 0;
  margin-top: 2px;
  color: var(--color-accent);
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 32px;
}
.hero-tag {
  padding: 5px 13px;
  border-radius: var(--radius-full);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
  transition: all var(--transition);
}
.hero-tag:hover {
  background: var(--color-primary-light);
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.hero-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.scroll-down {
  position: absolute;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  color: var(--color-text-faint);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  text-decoration: none;
  animation: bounce 2.5s ease-in-out infinite;
  transition: color var(--transition);
  z-index: 1;
}
.scroll-down:hover { color: var(--color-primary); text-decoration: none; }
@keyframes bounce {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50%       { transform: translateX(-50%) translateY(7px); }
}

/* =====================================================
   ABOUT
   ===================================================== */
.about-metrics {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 2px;
  margin-bottom: 64px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--color-border);
}

.metric-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 28px 16px;
  background: var(--color-surface);
  transition: background var(--transition);
  text-align: center;
}
.metric-item:hover { background: var(--color-surface-2); }

.metric-number {
  font-family: var(--font-mono);
  font-size: clamp(2rem, 3.5vw, 3rem);
  font-weight: 500;
  color: var(--color-primary);
  line-height: 1;
  margin-bottom: 8px;
  display: block;
}

.metric-label {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-text-muted);
}

.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 56px;
  align-items: start;
}

.about-text p {
  font-size: 1.025rem;
  line-height: 1.8;
  color: var(--color-text-muted);
  margin-bottom: 20px;
}
.about-text p:last-child { margin-bottom: 0; }

.about-highlights {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.highlight-card {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  padding: 20px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: all var(--transition);
}
.highlight-card:hover {
  border-color: var(--color-primary);
  background: var(--color-surface-2);
  transform: translateX(4px);
  box-shadow: -3px 0 0 var(--color-primary), var(--shadow-md);
}

.highlight-icon-wrap {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: var(--radius-sm);
  background: var(--color-primary-light);
  color: var(--color-primary);
  flex-shrink: 0;
}

.highlight-card h3 {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 4px;
}
.highlight-card p {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  line-height: 1.5;
}

/* =====================================================
   NEWS
   ===================================================== */
.news-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.news-card {
  display: flex;
  gap: 16px;
  align-items: flex-start;
  padding: 20px 22px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: all var(--transition);
  cursor: default;
}
.news-card:hover {
  border-color: var(--color-border-strong);
  background: var(--color-surface-2);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.news-date {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-width: 52px;
  padding: 8px 6px;
  background: var(--color-surface-2);
  border-radius: var(--radius-sm);
  flex-shrink: 0;
  text-align: center;
}
.news-date-month {
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-primary);
}
.news-date-year {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--color-text-muted);
}

.news-content { flex: 1; min-width: 0; }
.news-type {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 6px;
}
.news-headline {
  font-size: 0.925rem;
  font-weight: 600;
  color: var(--color-text);
  line-height: 1.4;
  margin-bottom: 4px;
}
.news-desc {
  font-size: 0.83rem;
  color: var(--color-text-muted);
  line-height: 1.5;
}

/* =====================================================
   RESEARCH
   ===================================================== */
.research-projects {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-bottom: 0;
}

.project-card {
  padding: 28px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}
.project-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
  opacity: 0;
  transition: opacity var(--transition);
}
.project-card:hover {
  border-color: var(--color-border-strong);
  background: var(--color-surface-2);
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}
.project-card:hover::before { opacity: 1; }

.project-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  background: var(--color-primary-light);
  color: var(--color-primary);
  margin-bottom: 18px;
}

.project-card h3 {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 10px;
  line-height: 1.3;
}

.project-card p {
  font-size: 0.89rem;
  color: var(--color-text-muted);
  line-height: 1.65;
  margin-bottom: 16px;
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.project-tag {
  padding: 3px 10px;
  border-radius: var(--radius-full);
  font-size: 0.72rem;
  font-weight: 600;
  background: var(--color-surface-3);
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
}

.interests-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.interest-card {
  padding: 24px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  text-align: center;
  transition: all var(--transition);
}
.interest-card:hover {
  border-color: var(--color-primary);
  background: var(--color-surface-2);
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.interest-icon-wrap {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 56px;
  height: 56px;
  border-radius: var(--radius-md);
  background: var(--color-primary-light);
  color: var(--color-primary);
  margin: 0 auto 16px;
  transition: all var(--transition);
}
.interest-card:hover .interest-icon-wrap {
  background: var(--color-primary);
  color: var(--color-bg);
}

.interest-card h3 {
  font-size: 0.925rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 8px;
  line-height: 1.3;
}
.interest-card p {
  font-size: 0.835rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* =====================================================
   CV TIMELINE
   ===================================================== */
.timeline {
  position: relative;
  padding-left: 36px;
}
.timeline::before {
  content: '';
  position: absolute;
  left: 8px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: linear-gradient(
    180deg,
    var(--color-primary) 0%,
    var(--color-purple) 50%,
    var(--color-accent) 100%
  );
  border-radius: 2px;
}

.timeline-item {
  position: relative;
  margin-bottom: 36px;
  padding: 24px 28px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: all var(--transition);
}
.timeline-item:last-child { margin-bottom: 0; }
.timeline-item::before {
  content: '';
  position: absolute;
  left: -32px;
  top: 28px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--color-bg-alt);
  border: 3px solid var(--color-primary);
  transition: all var(--transition);
  z-index: 1;
}
.timeline-item:nth-child(2)::before { border-color: var(--color-purple); }
.timeline-item:nth-child(3)::before { border-color: var(--color-accent); }
.timeline-item:nth-child(4)::before { border-color: var(--color-primary); }
.timeline-item:hover {
  border-color: var(--color-border-strong);
  background: var(--color-surface-2);
  transform: translateX(4px);
  box-shadow: var(--shadow-md);
}
.timeline-item:hover::before {
  background: var(--color-primary);
  box-shadow: 0 0 0 4px var(--color-primary-light);
}

.timeline-period {
  display: inline-flex;
  align-items: center;
  padding: 3px 10px;
  border-radius: var(--radius-full);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  background: var(--color-primary-light);
  color: var(--color-primary);
  border: 1px solid rgba(0, 200, 180, 0.2);
  margin-bottom: 10px;
}

.timeline-role {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 4px;
  line-height: 1.3;
}

.timeline-org {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-primary);
  margin-bottom: 8px;
}

.timeline-desc {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

.timeline-badge {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  margin-top: 10px;
  padding: 3px 10px;
  border-radius: var(--radius-full);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  background: var(--color-accent-light);
  color: var(--color-accent);
  border: 1px solid rgba(240, 165, 0, 0.25);
}

/* =====================================================
   PUBLICATIONS
   ===================================================== */
.pub-controls {
  display: flex;
  align-items: flex-start;
  gap: 20px;
  margin-bottom: 48px;
  flex-wrap: wrap;
}

.pub-search-wrap {
  flex: 1;
  min-width: 240px;
  position: relative;
}
.pub-search-wrap svg {
  position: absolute;
  left: 14px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--color-text-faint);
  pointer-events: none;
}

.pub-search {
  width: 100%;
  padding: 10px 16px 10px 42px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  color: var(--color-text);
  transition: all var(--transition);
  outline: none;
}
.pub-search::placeholder { color: var(--color-text-faint); }
.pub-search:focus {
  border-color: var(--color-primary);
  background: var(--color-surface-2);
  box-shadow: 0 0 0 3px var(--color-primary-light);
}

.pub-filters {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.filter-btn {
  padding: 8px 16px;
  border-radius: var(--radius-full);
  font-size: 0.82rem;
  font-weight: 600;
  font-family: var(--font-sans);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
  transition: all var(--transition);
  cursor: pointer;
  letter-spacing: 0.01em;
}
.filter-btn:hover {
  background: var(--color-surface-2);
  color: var(--color-text);
  border-color: var(--color-border-strong);
}
.filter-btn.active {
  background: var(--color-primary);
  color: #050c1a;
  border-color: var(--color-primary);
}
[data-theme="light"] .filter-btn.active { color: #ffffff; }

.pub-year-group {
  margin-bottom: 44px;
}
.pub-year-group:last-of-type { margin-bottom: 0; }

.pub-year-label {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--color-text-faint);
  letter-spacing: 0.08em;
  padding: 6px 0 16px;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.pub-year-label::after {
  content: attr(data-count);
  font-size: 0.7rem;
  padding: 1px 7px;
  background: var(--color-surface-2);
  border-radius: var(--radius-full);
  color: var(--color-text-muted);
}

.publications-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.publication-card {
  padding: 22px 24px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: all var(--transition);
  position: relative;
  border-left: 3px solid transparent;
}
.publication-card:hover {
  border-left-color: var(--color-primary);
  background: var(--color-surface-2);
  transform: translateX(3px);
  box-shadow: var(--shadow-sm);
}
.publication-card[data-type="thesis"] { border-left-color: var(--color-thesis); }
.publication-card[data-type="thesis"]:hover { border-left-color: var(--color-thesis); }

.pub-meta-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 10px;
}

.pub-badge {
  display: inline-flex;
  align-items: center;
  padding: 3px 10px;
  border-radius: var(--radius-full);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}
.pub-badge-journal  { background: var(--color-q1-bg);      color: var(--color-q1); }
.pub-badge-conf     { background: var(--color-conf-bg);     color: var(--color-conf); }
.pub-badge-preprint { background: var(--color-preprint-bg); color: var(--color-preprint); }
.pub-badge-thesis   { background: var(--color-thesis-bg);   color: var(--color-thesis); }

.pub-quality {
  display: inline-flex;
  align-items: center;
  padding: 2px 8px;
  border-radius: var(--radius-full);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 600;
}
.pub-q1 { background: var(--color-q1-bg); color: var(--color-q1); border: 1px solid currentColor; }
.pub-q2 { background: var(--color-q2-bg); color: var(--color-q2); border: 1px solid currentColor; }

.pub-cites {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--color-text-muted);
  margin-left: auto;
  padding: 2px 8px;
  background: var(--color-surface-2);
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
}

.pub-title {
  font-family: var(--font-sans);
  font-size: 0.975rem;
  font-weight: 600;
  line-height: 1.45;
  margin-bottom: 8px;
  color: var(--color-text);
}
.pub-title a {
  color: inherit;
}
.pub-title a:hover {
  color: var(--color-primary);
  text-decoration: none;
}

.pub-authors {
  font-size: 0.855rem;
  color: var(--color-text-muted);
  margin-bottom: 4px;
  line-height: 1.5;
}
.pub-venue {
  font-size: 0.83rem;
  color: var(--color-text-muted);
  margin-bottom: 12px;
  line-height: 1.4;
}
.pub-venue em { font-style: italic; }

.pub-no-results {
  display: none;
  text-align: center;
  padding: 60px 20px;
  color: var(--color-text-muted);
  font-size: 1rem;
}
.pub-no-results.visible { display: block; }

.scholar-cta {
  margin-top: 52px;
  text-align: center;
}

/* =====================================================
   CONTACT
   ===================================================== */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.contact-card {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  padding: 22px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: all var(--transition);
}
.contact-card:hover {
  border-color: var(--color-primary);
  background: var(--color-surface-2);
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.contact-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  background: var(--color-primary-light);
  color: var(--color-primary);
  flex-shrink: 0;
  transition: all var(--transition);
}
.contact-card:hover .contact-icon {
  background: var(--color-primary);
  color: var(--color-bg);
}

.contact-card h3 {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 4px;
}
.contact-card p,
.contact-card a {
  font-size: 0.855rem;
  color: var(--color-text-muted);
  line-height: 1.5;
}
.contact-card a:hover { color: var(--color-primary); }

/* =====================================================
   FOOTER
   ===================================================== */
.footer {
  background: var(--color-bg-alt);
  border-top: 1px solid var(--color-border);
  padding: 40px 0;
}

.footer-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
}

.footer-copy {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}
.footer-copy span { color: var(--color-primary); }

.footer-links {
  display: flex;
  gap: 20px;
}
.footer-links a {
  font-size: 0.82rem;
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--transition);
}
.footer-links a:hover {
  color: var(--color-primary);
  text-decoration: none;
}

/* =====================================================
   RESPONSIVE
   ===================================================== */

/* Tablet – 900px */
@media (max-width: 900px) {
  .section { padding: 80px 0; }

  .hero-content {
    flex-direction: column;
    text-align: center;
    gap: 36px;
    padding-bottom: 80px;
  }
  .hero-pre { justify-content: center; }
  .hero-affiliation { justify-content: center; }
  .hero-tags { justify-content: center; }
  .hero-links { justify-content: center; }

  .about-metrics { grid-template-columns: repeat(2, 1fr); }
  .about-grid { grid-template-columns: 1fr; gap: 40px; }

  .research-projects { grid-template-columns: 1fr; }
  .interests-grid { grid-template-columns: repeat(2, 1fr); }

  .contact-grid { grid-template-columns: repeat(2, 1fr); }

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

/* Mobile – 640px */
@media (max-width: 640px) {
  :root { --nav-height: 60px; }
  .section { padding: 64px 0; }
  .container { padding: 0 20px; }

  .nav-container { padding: 0 20px; }
  .nav-links {
    display: none;
    position: fixed;
    inset: var(--nav-height) 0 0 0;
    background: rgba(5, 12, 26, 0.97);
    backdrop-filter: blur(16px);
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 8px;
    z-index: 999;
  }
  [data-theme="light"] .nav-links {
    background: rgba(248, 251, 255, 0.97);
  }
  .nav-links.open { display: flex; }
  .nav-links a {
    font-size: 1.15rem;
    padding: 12px 24px;
  }
  .nav-toggle { display: flex; }

  .avatar-img { width: 140px; height: 140px; }
  .hero-name { font-size: 2.4rem; }

  .about-metrics { grid-template-columns: repeat(2, 1fr); }

  .interests-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }

  .pub-controls { flex-direction: column; }
  .pub-search-wrap { min-width: 100%; }

  .timeline { padding-left: 24px; }
  .timeline-item::before { left: -20px; width: 12px; height: 12px; }

  .footer-inner { flex-direction: column; text-align: center; }
}

/* Small – 400px */
@media (max-width: 400px) {
  .hero-name { font-size: 2rem; }
  .hero-links { flex-direction: column; align-items: stretch; }
  .hero-links .btn { justify-content: center; }
}