/* ==========================================================================
   jairoserrano.dev - Design System & Modern Responsive Stylesheet
   Author: Dr. Jairo Enrique Serrano Castañeda
   Aesthetics: Deep Space Dark (Default) & Clean Alabaster Light
   ========================================================================== */

:root {
  /* Color Palette - Dark Theme (Default) */
  --bg-primary: #070a13;
  --bg-secondary: #0c1222;
  --bg-card: rgba(16, 24, 44, 0.75);
  --bg-card-hover: rgba(24, 35, 64, 0.85);
  --bg-glass: rgba(14, 21, 38, 0.65);
  --border-color: rgba(255, 255, 255, 0.08);
  --border-highlight: rgba(56, 189, 248, 0.3);
  
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  
  --accent-cyan: #38bdf8;
  --accent-indigo: #6366f1;
  --accent-purple: #a855f7;
  --accent-emerald: #10b981;
  --accent-amber: #f59e0b;
  
  --gradient-primary: linear-gradient(135deg, #38bdf8 0%, #6366f1 50%, #a855f7 100%);
  --gradient-accent: linear-gradient(135deg, #0ea5e9, #38bdf8);
  --gradient-glow: radial-gradient(circle at 50% 50%, rgba(56, 189, 248, 0.12), transparent 70%);
  
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 8px 30px rgba(0, 0, 0, 0.35);
  --shadow-lg: 0 20px 50px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 35px rgba(56, 189, 248, 0.18);
  
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  
  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-heading: 'Outfit', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'SF Mono', Consolas, monospace;
}

[data-theme="light"] {
  --bg-primary: #f8fafc;
  --bg-secondary: #edf2f7;
  --bg-card: rgba(255, 255, 255, 0.85);
  --bg-card-hover: rgba(255, 255, 255, 0.98);
  --bg-glass: rgba(255, 255, 255, 0.75);
  --border-color: rgba(0, 0, 0, 0.08);
  --border-highlight: rgba(14, 165, 233, 0.4);
  
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 10px 30px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 20px 45px rgba(0, 0, 0, 0.12);
  --shadow-glow: 0 0 30px rgba(14, 165, 233, 0.15);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  color-scheme: dark light;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.65;
  overflow-x: hidden;
  position: relative;
  transition: background-color var(--transition-normal), color var(--transition-normal);
  -webkit-font-smoothing: antialiased;
}

/* Ambient Radial Glows */
.ambient-glow {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: 0;
  overflow: hidden;
}

.glow-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(120px);
  opacity: 0.18;
  transition: opacity var(--transition-slow);
}

[data-theme="light"] .glow-orb {
  opacity: 0.08;
}

.glow-orb-1 {
  width: 550px;
  height: 550px;
  background: #38bdf8;
  top: -150px;
  left: 10%;
}

.glow-orb-2 {
  width: 500px;
  height: 500px;
  background: #6366f1;
  top: 35%;
  right: -100px;
}

.glow-orb-3 {
  width: 450px;
  height: 450px;
  background: #a855f7;
  bottom: -100px;
  left: 20%;
}

/* Container */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
  position: relative;
  z-index: 1;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.25;
  color: var(--text-primary);
}

p {
  color: var(--text-secondary);
}

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

a:hover {
  color: #7dd3fc;
}

code, .font-mono {
  font-family: var(--font-mono);
}

.gradient-text {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
}

/* ==========================================================================
   Navigation Bar (Glassmorphic)
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  background: var(--bg-glass);
  border-bottom: 1px solid var(--border-color);
  transition: all var(--transition-normal);
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 4.5rem;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--text-primary);
}

.brand-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-card);
  border: 1px solid var(--border-highlight);
  box-shadow: var(--shadow-sm);
}

.brand-text {
  font-family: var(--font-mono);
  font-weight: 600;
  letter-spacing: -0.5px;
}

.brand-text .domain {
  color: var(--accent-cyan);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  list-style: none;
}

.nav-link {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 0.4rem 0.6rem;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.nav-link:hover, .nav-link.active {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.05);
}

[data-theme="light"] .nav-link:hover,
[data-theme="light"] .nav-link.active {
  background: rgba(0, 0, 0, 0.05);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.btn-icon {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-icon:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-highlight);
  transform: translateY(-1px);
}

.lang-switch {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  padding: 0 0.6rem;
  width: auto;
  gap: 0.25rem;
}

.mobile-toggle {
  display: none;
}

/* ==========================================================================
   Hero Section
   ========================================================================== */
.hero-section {
  padding: 5rem 0 4rem;
  position: relative;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.25fr 0.95fr;
  gap: 3.5rem;
  align-items: center;
}

.hero-badge-wrap {
  margin-bottom: 1.25rem;
}

.status-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 0.9rem;
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.3);
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  font-weight: 500;
  color: #34d399;
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #10b981;
  box-shadow: 0 0 10px #10b981;
  animation: pulse-dot 2s infinite;
}

@keyframes pulse-dot {
  0% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.7); }
  70% { transform: scale(1.1); box-shadow: 0 0 0 8px rgba(16, 185, 129, 0); }
  100% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(16, 185, 129, 0); }
}

.hero-title {
  font-size: 3rem;
  letter-spacing: -1px;
  margin-bottom: 0.75rem;
}

.hero-subtitle {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--accent-cyan);
  margin-bottom: 1.25rem;
  line-height: 1.4;
}

.hero-bio {
  font-size: 1.05rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
  line-height: 1.7;
}

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

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.4rem;
  font-size: 0.92rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
  border: 1px solid transparent;
}

.btn-primary {
  background: var(--gradient-primary);
  color: #ffffff;
  box-shadow: 0 4px 20px rgba(99, 102, 241, 0.35);
}

.btn-primary:hover {
  box-shadow: 0 6px 25px rgba(99, 102, 241, 0.5);
  transform: translateY(-2px);
  color: #ffffff;
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-highlight);
  transform: translateY(-2px);
  color: var(--accent-cyan);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
}

.btn-ghost:hover {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.05);
}

/* Verified Profiles Bar */
.hero-profiles {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.75rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-color);
}

.profile-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 0.8rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.profile-chip:hover {
  border-color: var(--border-highlight);
  color: var(--text-primary);
  background: var(--bg-card-hover);
  transform: translateY(-1px);
}

/* Hero Visual & Profile Card */
.hero-visual {
  position: relative;
  display: flex;
  justify-content: center;
}

.profile-card {
  width: 100%;
  max-width: 420px;
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  box-shadow: var(--shadow-lg);
  position: relative;
}

.profile-avatar-wrap {
  position: relative;
  width: 140px;
  height: 140px;
  margin: 0 auto 1.5rem;
}

.profile-avatar {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 50%;
  border: 3px solid var(--accent-cyan);
  box-shadow: var(--shadow-glow);
}

.floating-badge {
  position: absolute;
  background: var(--bg-secondary);
  border: 1px solid var(--border-highlight);
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius-full);
  font-size: 0.72rem;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  white-space: nowrap;
  box-shadow: var(--shadow-md);
  animation: float 4s ease-in-out infinite alternate;
}

.badge-top-left {
  top: -5px;
  left: -35px;
  animation-delay: 0s;
}

.badge-bottom-right {
  bottom: -5px;
  right: -30px;
  animation-delay: 1.5s;
}

@keyframes float {
  0% { transform: translateY(0); }
  100% { transform: translateY(-8px); }
}

/* Terminal Card in Hero */
.terminal-card {
  background: rgba(5, 8, 16, 0.85);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  font-family: var(--font-mono);
  font-size: 0.78rem;
}

.terminal-header {
  background: rgba(255, 255, 255, 0.04);
  padding: 0.5rem 0.8rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
  border-bottom: 1px solid var(--border-color);
}

.terminal-circle {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.circle-red { background: #ef4444; }
.circle-yellow { background: #f59e0b; }
.circle-green { background: #10b981; }

.terminal-title {
  margin-left: 0.5rem;
  font-size: 0.72rem;
  color: var(--text-muted);
}

.terminal-body {
  padding: 1rem;
  line-height: 1.6;
}

.t-key { color: #38bdf8; }
.t-val { color: #a7f3d0; }
.t-arr { color: #c084fc; }

/* ==========================================================================
   Metrics Strip
   ========================================================================== */
.metrics-section {
  padding: 2.5rem 0 4rem;
}

.metrics-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 1.25rem;
}

.metric-card {
  background: var(--bg-card);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem 1.25rem;
  text-align: center;
  transition: all var(--transition-normal);
}

.metric-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-highlight);
  box-shadow: var(--shadow-md);
}

.metric-num {
  font-family: var(--font-heading);
  font-size: 2.2rem;
  font-weight: 800;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 0.35rem;
}

.metric-label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
}

.metric-sub {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* ==========================================================================
   Section Headers & Shared Components
   ========================================================================== */
.section-padding {
  padding: 5rem 0;
}

.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 3.5rem;
}

.section-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--accent-cyan);
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-bottom: 0.75rem;
}

.section-title {
  font-size: 2.3rem;
  letter-spacing: -0.5px;
  margin-bottom: 1rem;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--text-secondary);
}

/* Filter Tabs */
.filter-tabs {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-bottom: 2.5rem;
}

.filter-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.5rem 1.1rem;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.filter-btn:hover {
  color: var(--text-primary);
  border-color: var(--border-highlight);
}

.filter-btn.active {
  background: var(--accent-cyan);
  color: #070a13;
  border-color: var(--accent-cyan);
  font-weight: 600;
  box-shadow: 0 2px 12px rgba(56, 189, 248, 0.3);
}

/* ==========================================================================
   Academic Leadership & Roles
   ========================================================================== */
.leadership-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.75rem;
}

.leadership-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2rem;
  position: relative;
  transition: all var(--transition-normal);
  display: flex;
  flex-direction: column;
}

.leadership-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-highlight);
  box-shadow: var(--shadow-md);
}

.card-icon-wrap {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: rgba(56, 189, 248, 0.1);
  color: var(--accent-cyan);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.25rem;
  font-size: 1.35rem;
}

.leadership-institution {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  color: var(--accent-indigo);
  letter-spacing: 0.5px;
  margin-bottom: 0.35rem;
}

.leadership-title {
  font-size: 1.35rem;
  margin-bottom: 0.75rem;
}

.leadership-desc {
  font-size: 0.95rem;
  line-height: 1.6;
  margin-bottom: 1.25rem;
  flex-grow: 1;
}

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

.tag-badge {
  font-size: 0.75rem;
  font-weight: 500;
  padding: 0.25rem 0.65rem;
  border-radius: var(--radius-full);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
}

[data-theme="light"] .tag-badge {
  background: rgba(0, 0, 0, 0.04);
}

/* ==========================================================================
   Research Areas
   ========================================================================== */
.research-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.75rem;
}

.research-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2rem;
  transition: all var(--transition-normal);
  display: flex;
  flex-direction: column;
}

.research-card:hover {
  border-color: var(--border-highlight);
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.research-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

.research-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
}

.icon-blue { background: rgba(56, 189, 248, 0.15); color: #38bdf8; }
.icon-purple { background: rgba(168, 85, 247, 0.15); color: #a855f7; }
.icon-amber { background: rgba(245, 158, 11, 0.15); color: #f59e0b; }
.icon-emerald { background: rgba(16, 185, 129, 0.15); color: #10b981; }

.research-title {
  font-size: 1.2rem;
}

.research-desc {
  font-size: 0.92rem;
  margin-bottom: 1.25rem;
  flex-grow: 1;
}

.research-bullets {
  list-style: none;
  margin-bottom: 1.25rem;
  font-size: 0.85rem;
}

.research-bullets li {
  position: relative;
  padding-left: 1.2rem;
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
}

.research-bullets li::before {
  content: "▹";
  position: absolute;
  left: 0;
  color: var(--accent-cyan);
}

/* ==========================================================================
   Featured Publications
   ========================================================================== */
.publications-list {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.pub-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem 1.75rem;
  transition: all var(--transition-normal);
  display: grid;
  grid-template-columns: 80px 1fr auto;
  gap: 1.5rem;
  align-items: center;
}

.pub-card:hover {
  border-color: var(--border-highlight);
  transform: translateX(4px);
  box-shadow: var(--shadow-sm);
}

.pub-year {
  font-family: var(--font-heading);
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--accent-cyan);
  text-align: center;
}

.pub-type {
  font-size: 0.7rem;
  text-transform: uppercase;
  color: var(--text-muted);
  font-weight: 600;
  letter-spacing: 0.5px;
}

.pub-title {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 0.4rem;
  line-height: 1.4;
  color: var(--text-primary);
}

.pub-authors {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 0.35rem;
}

.pub-venue {
  font-size: 0.82rem;
  color: var(--accent-indigo);
  font-style: italic;
}

.pub-actions {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.btn-pill {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius-full);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-pill:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-highlight);
  color: var(--text-primary);
}

/* ==========================================================================
   Featured Projects Grid
   ========================================================================== */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.75rem;
}

.project-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  transition: all var(--transition-normal);
  display: flex;
  flex-direction: column;
}

.project-card:hover {
  transform: translateY(-5px);
  border-color: var(--border-highlight);
  box-shadow: var(--shadow-md);
}

.project-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
}

.project-folder-icon {
  font-size: 1.6rem;
  color: var(--accent-cyan);
}

.project-links {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.project-link-icon {
  color: var(--text-muted);
  font-size: 1.1rem;
  transition: color var(--transition-fast);
}

.project-link-icon:hover {
  color: var(--text-primary);
}

.project-title {
  font-size: 1.2rem;
  margin-bottom: 0.6rem;
  color: var(--text-primary);
}

.project-desc {
  font-size: 0.9rem;
  line-height: 1.6;
  margin-bottom: 1.5rem;
  flex-grow: 1;
}

.project-tech {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: auto;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-muted);
}

/* ==========================================================================
   Skills & Tech Stack Matrix
   ========================================================================== */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
}

.skill-category {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem;
}

.skill-cat-title {
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--accent-cyan);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.skill-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.skill-item {
  font-size: 0.8rem;
  font-weight: 500;
  padding: 0.35rem 0.65rem;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
}

[data-theme="light"] .skill-item {
  background: rgba(0, 0, 0, 0.03);
}

/* ==========================================================================
   Contact Section
   ========================================================================== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
}

.contact-card-main {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2.5rem;
  box-shadow: var(--shadow-md);
}

.contact-item {
  display: flex;
  align-items: flex-start;
  gap: 1.25rem;
  margin-bottom: 1.75rem;
}

.contact-item:last-child {
  margin-bottom: 0;
}

.contact-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  background: rgba(56, 189, 248, 0.1);
  color: var(--accent-cyan);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  flex-shrink: 0;
}

.contact-info h4 {
  font-size: 0.85rem;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.5px;
  margin-bottom: 0.25rem;
}

.contact-value {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.copy-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  padding: 0.2rem;
  font-size: 0.9rem;
  transition: color var(--transition-fast);
}

.copy-btn:hover {
  color: var(--accent-cyan);
}

.collab-options {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.collab-box {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  transition: all var(--transition-normal);
  cursor: pointer;
}

.collab-box:hover {
  border-color: var(--border-highlight);
  transform: translateX(4px);
}

.collab-title {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 0.35rem;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.collab-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

/* ==========================================================================
   Footer
   ========================================================================== */
.site-footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: 4rem 0 2rem;
  margin-top: 4rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 3rem;
  margin-bottom: 3rem;
}

.footer-quote {
  font-style: italic;
  color: var(--accent-cyan);
  margin-top: 0.75rem;
  font-size: 0.95rem;
}

.footer-col h4 {
  font-size: 0.95rem;
  margin-bottom: 1.25rem;
  color: var(--text-primary);
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  font-size: 0.88rem;
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Toast Notification */
.toast {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-highlight);
  color: var(--text-primary);
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-lg);
  font-size: 0.88rem;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  z-index: 1000;
  opacity: 0;
  transform: translateY(20px);
  pointer-events: none;
  transition: all var(--transition-normal);
}

.toast.show {
  opacity: 1;
  transform: translateY(0);
}

/* BibTeX Modal */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(6px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 2000;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-normal);
  padding: 1.5rem;
}

.modal-overlay.active {
  opacity: 1;
  pointer-events: auto;
}

.modal-box {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  width: 100%;
  max-width: 600px;
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

.modal-header {
  padding: 1.25rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--border-color);
}

.modal-body {
  padding: 1.5rem;
}

.modal-code {
  background: #050810;
  color: #38bdf8;
  padding: 1rem;
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  overflow-x: auto;
  white-space: pre;
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */
@media (max-width: 1024px) {
  .hero-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }
  
  .hero-actions, .hero-profiles {
    justify-content: center;
  }
  
  .metrics-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .research-grid, .projects-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .skills-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .leadership-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 4.5rem;
    left: 0;
    width: 100%;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    flex-direction: column;
    padding: 1.5rem;
    gap: 1rem;
  }
  
  .nav-links.open {
    display: flex;
  }
  
  .mobile-toggle {
    display: inline-flex;
  }
  
  .hero-title {
    font-size: 2.2rem;
  }
  
  .metrics-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .research-grid, .projects-grid, .skills-grid {
    grid-template-columns: 1fr;
  }
  
  .contact-grid {
    grid-template-columns: 1fr;
  }
  
  .pub-card {
    grid-template-columns: 1fr;
    gap: 1rem;
  }
  
  .pub-actions {
    justify-content: flex-start;
  }
  
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
  
  .footer-bottom {
    flex-direction: column;
    gap: 1rem;
    text-align: center;
  }
}