/* ==========================================================================
   AI & Machine Learning Engineer Portfolio - Main Stylesheet
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. Design Tokens & CSS Variables
   -------------------------------------------------------------------------- */
:root {
  /* Color Palette - Dark Theme (Default) */
  --bg-primary: #0a0f1d;
  --bg-secondary: #111827;
  --bg-tertiary: #1f293d;
  --bg-card: rgba(17, 24, 39, 0.75);
  --bg-card-hover: rgba(31, 41, 61, 0.9);
  --bg-glass: rgba(10, 15, 29, 0.85);
  --border-color: rgba(255, 255, 255, 0.08);
  --border-color-hover: rgba(99, 102, 241, 0.45);

  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;

  --accent-primary: #6366f1; /* Indigo */
  --accent-secondary: #06b6d4; /* Cyan */
  --accent-tertiary: #10b981; /* Emerald */
  --accent-gradient: linear-gradient(135deg, #6366f1 0%, #06b6d4 50%, #10b981 100%);
  --accent-glow: 0 0 25px rgba(99, 102, 241, 0.35);

  --badge-bg: rgba(99, 102, 241, 0.12);
  --badge-text: #818cf8;
  --badge-border: rgba(99, 102, 241, 0.25);

  /* Typography */
  --font-sans: 'Pretendard', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Noto Sans KR', sans-serif;
  --font-mono: 'Fira Code', 'JetBrains Mono', Consolas, monospace;

  /* Spacing & Layout */
  --container-max-width: 1200px;
  --header-height: 72px;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;

  /* Transitions & Shadows */
  --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);
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.25);
  --shadow-md: 0 10px 30px -10px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 20px 40px -15px rgba(0, 0, 0, 0.6);
  --shadow-glow: 0 0 30px rgba(99, 102, 241, 0.2);
}

/* Light Theme Variables */
[data-theme="light"] {
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f1f5f9;
  --bg-card: rgba(255, 255, 255, 0.88);
  --bg-card-hover: #ffffff;
  --bg-glass: rgba(248, 250, 252, 0.88);
  --border-color: rgba(0, 0, 0, 0.08);
  --border-color-hover: rgba(99, 102, 241, 0.5);

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

  --badge-bg: rgba(99, 102, 241, 0.08);
  --badge-text: #4f46e5;
  --badge-border: rgba(99, 102, 241, 0.2);

  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 10px 25px -5px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 20px 35px -10px rgba(0, 0, 0, 0.12);
  --shadow-glow: 0 0 30px rgba(99, 102, 241, 0.12);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + 20px);
}

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;
}

/* Background Ambient Glow */
.bg-glow-container {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  overflow: hidden;
  pointer-events: none;
  z-index: 0;
}

.bg-glow-circle-1 {
  position: absolute;
  top: -15%;
  right: -10%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(99, 102, 241, 0.15) 0%, rgba(99, 102, 241, 0) 70%);
  border-radius: 50%;
  filter: blur(60px);
}

.bg-glow-circle-2 {
  position: absolute;
  top: 40%;
  left: -15%;
  width: 650px;
  height: 650px;
  background: radial-gradient(circle, rgba(6, 182, 212, 0.12) 0%, rgba(6, 182, 212, 0) 70%);
  border-radius: 50%;
  filter: blur(70px);
}

.bg-glow-circle-3 {
  position: absolute;
  bottom: -10%;
  right: 15%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(16, 185, 129, 0.1) 0%, rgba(16, 185, 129, 0) 70%);
  border-radius: 50%;
  filter: blur(60px);
}

.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  position: relative;
  z-index: 1;
}

section {
  padding: 5.5rem 0;
}

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

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

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

/* --------------------------------------------------------------------------
   3. Typography & Section Headers
   -------------------------------------------------------------------------- */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.25;
  color: var(--text-primary);
}

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

.section-header {
  text-align: center;
  max-width: 750px;
  margin: 0 auto 3.5rem;
}

.section-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 1rem;
  background: var(--badge-bg);
  color: var(--badge-text);
  border: 1px solid var(--badge-border);
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 1rem;
}

.section-title {
  font-size: 2.3rem;
  letter-spacing: -0.02em;
  margin-bottom: 0.8rem;
}

.section-desc {
  color: var(--text-secondary);
  font-size: 1.05rem;
  line-height: 1.6;
}

/* --------------------------------------------------------------------------
   4. Header & Navigation
   -------------------------------------------------------------------------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-height);
  background: var(--bg-glass);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
  z-index: 1000;
  transition: all var(--transition-normal);
}

.site-header.scrolled {
  box-shadow: var(--shadow-md);
  height: 64px;
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.site-logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 800;
  font-size: 1.25rem;
  letter-spacing: -0.03em;
}

.site-logo .logo-icon {
  width: 36px;
  height: 36px;
  background: var(--accent-gradient);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 1.1rem;
  box-shadow: var(--accent-glow);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 1.8rem;
  list-style: none;
}

.nav-link {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-secondary);
  position: relative;
  padding: 0.4rem 0;
}

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

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent-gradient);
  transition: width var(--transition-fast);
  border-radius: 2px;
}

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

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.8rem;
}

.theme-toggle-btn {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
  background: var(--bg-tertiary);
  transition: var(--transition-fast);
}

.theme-toggle-btn:hover {
  color: var(--accent-primary);
  border-color: var(--accent-primary);
  transform: rotate(15deg);
}

.mobile-menu-toggle {
  display: none;
  font-size: 1.4rem;
  color: var(--text-primary);
}

/* --------------------------------------------------------------------------
   5. Buttons & Badges
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-md);
  font-size: 0.95rem;
  font-weight: 600;
  transition: all var(--transition-fast);
  box-shadow: var(--shadow-sm);
  text-align: center;
}

.btn-primary {
  background: var(--accent-gradient);
  color: #ffffff;
  box-shadow: var(--shadow-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 35px rgba(99, 102, 241, 0.5);
  color: #ffffff;
}

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

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

.btn-sm {
  padding: 0.45rem 0.9rem;
  font-size: 0.85rem;
  border-radius: var(--radius-sm);
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.25rem 0.65rem;
  background: var(--badge-bg);
  color: var(--badge-text);
  border: 1px solid var(--badge-border);
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  font-weight: 600;
}

/* --------------------------------------------------------------------------
   6. Hero Section with Real Avatar & Showcase
   -------------------------------------------------------------------------- */
.hero-section {
  padding-top: calc(var(--header-height) + 3rem);
  padding-bottom: 5.5rem;
  min-height: 88vh;
  display: flex;
  align-items: center;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 3.5rem;
  align-items: center;
}

.hero-badge-live {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.4rem 1rem;
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.3);
  border-radius: var(--radius-full);
  color: #10b981;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
}

.pulse-dot {
  width: 8px;
  height: 8px;
  background-color: #10b981;
  border-radius: 50%;
  box-shadow: 0 0 0 rgba(16, 185, 129, 0.7);
  animation: pulse-animation 2s infinite;
}

@keyframes pulse-animation {
  0% { box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.7); }
  70% { box-shadow: 0 0 0 10px rgba(16, 185, 129, 0); }
  100% { box-shadow: 0 0 0 0 rgba(16, 185, 129, 0); }
}

.hero-profile-row {
  display: flex;
  align-items: center;
  gap: 1.2rem;
  margin-bottom: 0.6rem;
}

.hero-avatar-wrapper {
  position: relative;
  width: 104px;
  height: 134px;
  aspect-ratio: 3.5 / 4.5;
  flex-shrink: 0;
}

.hero-avatar-img {
  width: 100%;
  height: 100%;
  border-radius: 18px;
  object-fit: cover;
  border: 2.5px solid var(--accent-primary);
  box-shadow: var(--shadow-md);
  position: relative;
  z-index: 1;
}

.hero-avatar-glow {
  position: absolute;
  top: -4px;
  left: -4px;
  right: -4px;
  bottom: -4px;
  border-radius: 20px;
  background: var(--accent-gradient);
  filter: blur(8px);
  opacity: 0.55;
  z-index: 0;
}

.hero-profile-info {
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.hero-title {
  font-size: 3rem;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 0.3rem;
}

.hero-name-ko {
  /* not used – handled by gradient-text */
}

.hero-name-en {
  font-size: 0.65em;
  font-weight: 500;
  color: var(--text-secondary);
}

.hero-affiliation {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.95rem;
  color: var(--text-secondary);
  font-weight: 500;
}

/* Role Title - Sans-Serif & Middle Dot */
.hero-role-title {
  font-family: var(--font-sans);
  font-size: 1.32rem;
  font-weight: 700;
  color: #38bdf8;
  margin: 1.1rem 0 0.8rem;
  letter-spacing: -0.01em;
}

.hero-description {
  font-size: 0.98rem;
  color: var(--text-secondary);
  margin-bottom: 1.3rem;
  max-width: 540px;
  line-height: 1.65;
}

/* Credentials Grid in Hero Left Column */
.hero-creds-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.8rem;
  margin: 1.2rem 0;
  max-width: 540px;
}

.hero-cred-card {
  background: rgba(17, 24, 39, 0.75);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: var(--radius-sm);
  padding: 0.85rem 1rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  backdrop-filter: blur(8px);
}

.hero-cred-icon {
  font-size: 1.35rem;
  flex-shrink: 0;
  color: var(--accent-primary);
}

.hero-cred-body {
  display: flex;
  flex-direction: column;
}

.hero-cred-val {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
}

.hero-cred-lbl {
  font-size: 0.74rem;
  color: var(--text-muted);
  margin-top: 0.15rem;
  line-height: 1.3;
}

/* Hero Bottom Divider & Actions Row */
.hero-bottom-divider {
  width: 100%;
  max-width: 540px;
  height: 1px;
  background: rgba(255, 255, 255, 0.08);
  margin: 1.4rem 0 1.2rem;
}

.hero-actions-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 540px;
  gap: 0.8rem;
  flex-wrap: wrap;
}

.hero-action-buttons {
  display: flex;
  gap: 0.65rem;
  flex-wrap: wrap;
}

.hero-dark-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background: rgba(31, 41, 61, 0.7);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--text-primary);
  padding: 0.6rem 1rem;
  border-radius: var(--radius-sm);
  font-size: 0.86rem;
  font-weight: 600;
  text-decoration: none;
  transition: all var(--transition-fast);
}

.hero-dark-btn:hover {
  background: var(--accent-primary);
  border-color: var(--accent-primary);
  color: #ffffff;
  transform: translateY(-2px);
}

.hero-social-circles {
  display: flex;
  gap: 0.55rem;
}

.hero-circle-btn {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: rgba(31, 41, 61, 0.7);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.9rem;
  text-decoration: none;
  transition: all var(--transition-fast);
}

.hero-circle-btn:hover {
  background: var(--accent-primary);
  color: #ffffff;
  border-color: var(--accent-primary);
  transform: translateY(-2px);
}

/* --------------------------------------------------------------------------
   Featured Researcher Showcase Card (Matching Reference Layout)
   -------------------------------------------------------------------------- */
.showcase-card {
  background: #111827;
  border: 1px solid #1f293d;
  border-radius: 16px;
  padding: 1.6rem 1.8rem;
  box-shadow: 0 20px 40px -10px rgba(0, 0, 0, 0.5);
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  transition: transform var(--transition-normal), border-color var(--transition-normal);
}

.showcase-card:hover {
  border-color: rgba(99, 102, 241, 0.45);
}

.showcase-top-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.8rem;
}

.showcase-badge-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  background: rgba(244, 63, 94, 0.15);
  color: #fb7185;
  border: 1px solid #f43f5e;
  padding: 0.32rem 0.85rem;
  border-radius: 20px;
  font-size: 0.82rem;
  font-weight: 700;
}

.showcase-author-tag {
  font-size: 0.84rem;
  color: #34d399;
  font-weight: 600;
}

.showcase-paper-info {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.showcase-paper-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: #f8fafc;
  line-height: 1.4;
}

.showcase-paper-desc {
  font-size: 0.86rem;
  color: #94a3b8;
  line-height: 1.55;
}

.showcase-spectrum-section {
  display: flex;
  flex-direction: column;
}

.showcase-spectrum-header {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  font-size: 0.78rem;
  font-weight: 700;
  color: #94a3b8;
  letter-spacing: 0.06em;
  margin-bottom: 0.7rem;
}

.showcase-spectrum-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.6rem;
}

.spectrum-tag {
  background: rgba(17, 24, 39, 0.9);
  border: 1px solid #1f293d;
  color: #e2e8f0;
  padding: 0.55rem 0.8rem;
  border-radius: 8px;
  font-size: 0.8rem;
  font-weight: 500;
  text-align: center;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.showcase-cta-container {
  margin-top: 0.3rem;
}

.showcase-cta-btn {
  display: block;
  width: 100%;
  padding: 0.82rem;
  text-align: center;
  background: linear-gradient(135deg, #3b82f6 0%, #06b6d4 50%, #10b981 100%);
  color: #0f172a;
  font-weight: 700;
  font-size: 0.92rem;
  border-radius: 10px;
  text-decoration: none;
  transition: all var(--transition-fast);
  box-shadow: 0 4px 15px rgba(6, 182, 212, 0.25);
}

.showcase-cta-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(6, 182, 212, 0.4);
  color: #000000;
}

/* --------------------------------------------------------------------------
   7. About Section
   -------------------------------------------------------------------------- */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
}

.about-text {
  font-size: 1.05rem;
  color: var(--text-secondary);
  line-height: 1.8;
}

.about-text p {
  margin-bottom: 1.2rem;
}

.about-cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.2rem;
}

.competency-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  padding: 1.4rem;
  border-radius: var(--radius-md);
  backdrop-filter: blur(12px);
  transition: all var(--transition-normal);
}

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

.competency-icon {
  width: 42px;
  height: 42px;
  background: var(--badge-bg);
  color: var(--accent-primary);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  margin-bottom: 1rem;
}

.competency-title {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 0.4rem;
}

.competency-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* --------------------------------------------------------------------------
   8. Publications Section
   -------------------------------------------------------------------------- */
.publications-list {
  display: flex;
  flex-direction: column;
  gap: 1.6rem;
}

.pub-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2rem;
  backdrop-filter: blur(12px);
  transition: all var(--transition-normal);
  position: relative;
}

.pub-card:hover {
  border-color: var(--border-color-hover);
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.pub-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.8rem;
}

.pub-badge {
  background: rgba(99, 102, 241, 0.15);
  color: #818cf8;
  font-weight: 700;
  font-size: 0.82rem;
}

.pub-status-tag {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  font-weight: 600;
  color: #10b981;
}

.pub-title {
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 0.6rem;
  line-height: 1.35;
}

.pub-authors {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 0.4rem;
}

.pub-authors strong {
  color: var(--accent-secondary);
  text-decoration: underline;
}

.pub-venue {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  color: var(--accent-primary);
  font-weight: 600;
  margin-bottom: 1rem;
}

.pub-desc {
  font-size: 0.92rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 1.4rem;
}

.pub-actions {
  display: flex;
  gap: 0.8rem;
  flex-wrap: wrap;
}

/* --------------------------------------------------------------------------
   9. Projects Section & Modal
   -------------------------------------------------------------------------- */
.projects-filter-bar {
  display: flex;
  justify-content: center;
  gap: 0.8rem;
  margin-bottom: 2.5rem;
  flex-wrap: wrap;
}

.filter-btn {
  padding: 0.5rem 1.2rem;
  border-radius: var(--radius-full);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  transition: all var(--transition-fast);
}

.filter-btn:hover, .filter-btn.active {
  background: var(--accent-primary);
  color: #ffffff;
  border-color: var(--accent-primary);
  box-shadow: var(--shadow-glow);
}

.projects-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
}

.project-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2rem;
  backdrop-filter: blur(12px);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

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

.project-card-highlight {
  border-color: rgba(99, 102, 241, 0.45);
  box-shadow: 0 0 30px rgba(99, 102, 241, 0.12);
  position: relative;
}

.project-card-highlight::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--accent-gradient);
}

.project-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 1.2rem;
}

.project-icon-box {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: var(--badge-bg);
  border: 1px solid var(--badge-border);
  color: var(--accent-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
}

.project-period {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.project-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.4rem;
  line-height: 1.35;
}

.project-subtitle {
  font-size: 0.85rem;
  color: var(--accent-secondary);
  font-family: var(--font-mono);
  margin-bottom: 1rem;
}

.project-desc {
  font-size: 0.93rem;
  color: var(--text-secondary);
  margin-bottom: 1.3rem;
  line-height: 1.6;
}

.project-metrics-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.6rem;
  padding: 0.8rem;
  background: rgba(0, 0, 0, 0.2);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  margin-bottom: 1.3rem;
}

.metric-col {
  text-align: center;
}

.metric-val {
  font-size: 1rem;
  font-weight: 700;
  color: #10b981;
}

.metric-lbl {
  font-size: 0.7rem;
  color: var(--text-muted);
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 1.3rem;
}

.tag {
  padding: 0.2rem 0.6rem;
  border-radius: var(--radius-sm);
  background: var(--bg-tertiary);
  font-size: 0.75rem;
  color: var(--text-secondary);
  font-family: var(--font-mono);
  border: 1px solid var(--border-color);
}

/* Project Card Teaser Visual Banner */
.project-card-teaser-wrapper {
  position: relative;
  width: 100%;
  max-height: 180px;
  overflow: hidden;
  border-radius: var(--radius-sm);
  margin-bottom: 1.2rem;
  background: #ffffff;
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 4px;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-normal), border-color var(--transition-normal);
}

.project-card:hover .project-card-teaser-wrapper {
  border-color: var(--border-color-hover);
}

.project-card-teaser-img {
  width: 100%;
  display: block;
  border-radius: var(--radius-lg);
  object-fit: cover;
  max-height: 180px;
  transition: transform 0.3s ease;
}

.project-teaser-click {
  cursor: pointer;
}

.project-teaser-click:hover .project-card-teaser-img {
  transform: scale(1.03);
}

.project-card-teaser-badge {
  position: absolute;
  top: 10px;
  right: 10px;
  background: rgba(10, 15, 29, 0.85);
  color: var(--accent-secondary);
  font-size: 1.1rem;
  padding: 0.3rem 0.5rem;
  border-radius: var(--radius-full);
  border: 1px solid rgba(6, 182, 212, 0.35);
  backdrop-filter: blur(8px);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
  cursor: pointer;
  transition: all 0.2s ease;
  line-height: 1;
}

.project-card-teaser-badge:hover {
  background: rgba(6, 182, 212, 0.25);
  border-color: var(--accent-secondary);
  transform: scale(1.15);
  box-shadow: 0 0 16px rgba(6, 182, 212, 0.4);
}

.project-bottom-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 1.2rem;
  border-top: 1px solid var(--border-color);
}

.project-detail-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--accent-primary);
  background: none;
  border: none;
  cursor: pointer;
  transition: var(--transition-fast);
  padding: 0;
}

.project-detail-btn:hover {
  color: var(--accent-secondary);
  gap: 0.6rem;
}

.project-links {
  display: flex;
  gap: 0.8rem;
}

.project-link-btn {
  font-size: 1.15rem;
  color: var(--text-secondary);
  transition: var(--transition-fast);
}

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

/* --------------------------------------------------------------------------
   Modal Overlay & Dialog Styles
   -------------------------------------------------------------------------- */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: 2500;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity 0.25s ease, visibility 0.25s ease;
  padding: 1.5rem;
}

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

.modal-content {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color-hover);
  border-radius: var(--radius-lg);
  width: 100%;
  max-width: 820px;
  max-height: 88vh;
  overflow-y: auto;
  padding: 2.5rem;
  position: relative;
  box-shadow: 0 25px 60px -15px rgba(0, 0, 0, 0.7), var(--accent-glow);
  transform: scale(0.94) translateY(20px);
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.modal-overlay.active .modal-content {
  transform: scale(1) translateY(0);
}

.modal-close-btn {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  width: 38px;
  height: 38px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.modal-close-btn:hover {
  background: var(--accent-primary);
  color: #ffffff;
  border-color: var(--accent-primary);
  transform: rotate(90deg);
}

.modal-header {
  margin-bottom: 1.8rem;
  padding-bottom: 1.2rem;
  border-bottom: 1px solid var(--border-color);
}

.modal-badge {
  display: inline-block;
  margin-bottom: 0.6rem;
}

.modal-title {
  font-size: 1.45rem;
  font-weight: 800;
  line-height: 1.35;
  margin-bottom: 0.4rem;
  color: var(--text-primary);
}

.modal-subtitle {
  font-size: 0.9rem;
  color: var(--accent-secondary);
  font-family: var(--font-mono);
}

.modal-section {
  margin-bottom: 1.6rem;
}

.modal-section-title {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 0.6rem;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.modal-section-title i {
  color: var(--accent-primary);
}

.modal-text {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

.architecture-diagram-box {
  background: rgba(0, 0, 0, 0.35);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 1rem 1.2rem;
  font-family: var(--font-mono);
  font-size: 0.84rem;
  color: #38bdf8;
  line-height: 1.6;
  word-break: break-all;
}

/* Modal Figure / Teaser Image Container */
.modal-image-container {
  background: rgba(0, 0, 0, 0.25);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 0.8rem;
  text-align: center;
}

.modal-teaser-img {
  width: 100%;
  max-height: 400px;
  object-fit: contain;
  border-radius: var(--radius-sm);
  background: #ffffff;
  padding: 6px;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.modal-image-caption {
  margin-top: 0.6rem;
  font-size: 0.84rem;
  color: var(--text-secondary);
  font-family: var(--font-mono);
  line-height: 1.5;
}

.modal-results-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  padding-left: 0;
}

.modal-results-list li {
  position: relative;
  padding-left: 1.4rem;
  font-size: 0.93rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.modal-results-list li::before {
  content: "✔";
  position: absolute;
  left: 0;
  top: 0;
  color: var(--accent-tertiary);
  font-weight: bold;
}

/* --------------------------------------------------------------------------
   10. Skills Section
   -------------------------------------------------------------------------- */
.skills-container {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.8rem;
}

.skill-category-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.8rem;
  backdrop-filter: blur(12px);
  transition: border-color var(--transition-normal), box-shadow var(--transition-normal);
}

.skill-category-card:hover {
  border-color: var(--border-color-hover);
  box-shadow: var(--shadow-md);
}

.skill-category-header {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  margin-bottom: 1.5rem;
  padding-bottom: 0.8rem;
  border-bottom: 1px solid var(--border-color);
}

.skill-category-icon {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  background: var(--accent-gradient);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
}

.skill-category-title {
  font-size: 1.15rem;
  font-weight: 700;
}

.skills-list {
  display: flex;
  flex-direction: column;
  gap: 1.1rem;
}

.skill-item {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.skill-info {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
}

.skill-name {
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--text-primary);
}

.skill-level-badge {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent-secondary);
  font-family: var(--font-mono);
}

.skill-progress-bar {
  width: 100%;
  height: 5px;
  background: var(--bg-tertiary);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.skill-progress-fill {
  height: 100%;
  background: var(--accent-gradient);
  border-radius: var(--radius-full);
  transition: width 1s ease-in-out;
}

.skill-detail-desc {
  font-size: 0.78rem;
  color: var(--text-muted);
  line-height: 1.35;
}

/* --------------------------------------------------------------------------
   11. Experience & Awards Section
   -------------------------------------------------------------------------- */
.experience-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
}

.timeline-column-title {
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 1.8rem;
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.timeline {
  position: relative;
  padding-left: 1.8rem;
  border-left: 2px solid var(--border-color);
  display: flex;
  flex-direction: column;
  gap: 2.2rem;
}

.timeline-item {
  position: relative;
}

.timeline-dot {
  position: absolute;
  top: 4px;
  left: -2.25rem;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background: var(--accent-primary);
  border: 3px solid var(--bg-primary);
  box-shadow: 0 0 10px rgba(99, 102, 241, 0.6);
}

.timeline-period {
  font-size: 0.8rem;
  color: var(--accent-secondary);
  font-family: var(--font-mono);
  margin-bottom: 0.3rem;
}

.timeline-title {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 0.2rem;
}

.timeline-subtitle {
  font-size: 0.95rem;
  color: var(--text-secondary);
  font-weight: 500;
  margin-bottom: 0.8rem;
}

.timeline-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.timeline-bullets {
  margin-top: 0.6rem;
  padding-left: 1.2rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* Awards Vertical List */
.awards-vertical-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.award-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.3rem;
  backdrop-filter: blur(12px);
  display: flex;
  gap: 1.2rem;
  align-items: flex-start;
  transition: transform var(--transition-fast), border-color var(--transition-fast);
}

.award-card:hover {
  border-color: #f59e0b;
  transform: translateY(-2px);
}

.award-icon {
  font-size: 1.8rem;
  color: #f59e0b;
  flex-shrink: 0;
}

.award-title {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.award-org {
  font-size: 0.8rem;
  color: var(--accent-secondary);
  font-family: var(--font-mono);
  margin-bottom: 0.3rem;
}

.award-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.4;
}

/* Personal Projects List */
.personal-projects-list {
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
}

.personal-project-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  padding: 0.9rem 1.2rem;
  border-radius: var(--radius-sm);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  transition: border-color var(--transition-fast);
}

.personal-project-item:hover {
  border-color: var(--accent-primary);
}

.personal-project-title {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-primary);
}

.project-index-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 24px;
  height: 20px;
  padding: 0 0.35rem;
  background: var(--badge-bg);
  border: 1px solid var(--badge-border);
  border-radius: 4px;
  color: var(--accent-secondary);
  font-family: var(--font-mono);
  font-size: 0.76rem;
  font-weight: 700;
  flex-shrink: 0;
}

.personal-project-period {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  flex-shrink: 0;
}

/* --------------------------------------------------------------------------
   12. Contact Section
   -------------------------------------------------------------------------- */
.contact-wrapper {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 3.5rem 2.5rem;
  text-align: center;
  backdrop-filter: blur(16px);
  box-shadow: var(--shadow-lg);
  position: relative;
  overflow: hidden;
}

.contact-title {
  font-size: 2.2rem;
  margin-bottom: 1rem;
}

.contact-desc {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 2.5rem;
}

.contact-email-box {
  display: inline-flex;
  align-items: center;
  gap: 1rem;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  padding: 0.8rem 1.5rem;
  border-radius: var(--radius-full);
  margin-bottom: 2.5rem;
  box-shadow: var(--shadow-sm);
}

.contact-email-text {
  font-family: var(--font-mono);
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
}

.copy-email-btn {
  background: var(--accent-primary);
  color: #fff;
  border-radius: var(--radius-full);
  padding: 0.4rem 0.9rem;
  font-size: 0.8rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 0.4rem;
  transition: var(--transition-fast);
}

.copy-email-btn:hover {
  background: var(--accent-secondary);
}

.contact-social-links {
  display: flex;
  justify-content: center;
  gap: 1.2rem;
  flex-wrap: wrap;
}

/* --------------------------------------------------------------------------
   13. Footer
   -------------------------------------------------------------------------- */
.site-footer {
  padding: 2.5rem 0;
  border-top: 1px solid var(--border-color);
  background: var(--bg-glass);
  text-align: center;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* --------------------------------------------------------------------------
   14. Project Detail Modal
   -------------------------------------------------------------------------- */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: 2000;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-normal);
  padding: 1.5rem;
}

.modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

.modal-content {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  max-width: 820px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  padding: 2.5rem;
  position: relative;
  box-shadow: var(--shadow-lg);
  transform: translateY(20px) scale(0.97);
  transition: transform var(--transition-normal);
}

.modal-overlay.active .modal-content {
  transform: translateY(0) scale(1);
}

.modal-close-btn {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  border: 1px solid var(--border-color);
  transition: var(--transition-fast);
}

.modal-close-btn:hover {
  color: #fff;
  background: #ef4444;
  border-color: #ef4444;
}

.modal-header {
  margin-bottom: 1.5rem;
  padding-right: 2.5rem;
}

.modal-badge {
  display: inline-block;
  margin-bottom: 0.5rem;
}

.modal-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 0.3rem;
}

.modal-subtitle {
  color: var(--accent-secondary);
  font-family: var(--font-mono);
  font-size: 0.9rem;
}

.modal-section {
  margin-bottom: 1.4rem;
}

.modal-section-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.modal-section-title i {
  color: var(--accent-primary);
}

.modal-text {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

.architecture-diagram-box {
  background: rgba(0, 0, 0, 0.3);
  border: 1px dashed var(--border-color-hover);
  border-radius: var(--radius-sm);
  padding: 0.9rem 1.2rem;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: #38bdf8;
  line-height: 1.6;
}

.modal-results-list {
  padding-left: 1.2rem;
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* Toast Notification */
.toast-notification {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: #10b981;
  color: #ffffff;
  padding: 0.8rem 1.5rem;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.9rem;
  display: flex;
  align-items: center;
  gap: 0.6rem;
  box-shadow: var(--shadow-lg);
  z-index: 3000;
  opacity: 0;
  transform: translateY(20px);
  pointer-events: none;
  transition: all var(--transition-normal);
}

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

/* --------------------------------------------------------------------------
   15. Responsive Breakpoints
   -------------------------------------------------------------------------- */
@media (max-width: 1024px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 3rem;
  }
  .skills-container {
    grid-template-columns: 1fr;
  }
  .projects-grid {
    grid-template-columns: 1fr;
  }
  .experience-grid {
    grid-template-columns: 1fr;
  }
  .about-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .nav-menu {
    position: fixed;
    top: var(--header-height);
    left: 0;
    width: 100%;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    flex-direction: column;
    padding: 2rem 1.5rem;
    gap: 1.5rem;
    transform: translateY(-150%);
    transition: transform var(--transition-normal);
  }

  .nav-menu.mobile-open {
    transform: translateY(0);
    box-shadow: var(--shadow-lg);
  }

  .mobile-menu-toggle {
    display: block;
  }

  .hero-profile-row {
    flex-direction: column;
    align-items: flex-start;
    gap: 1rem;
  }

  .hero-title {
    font-size: 2.3rem;
  }

  .hero-stats-grid {
    grid-template-columns: 1fr;
  }

  .about-cards {
    grid-template-columns: 1fr;
  }

  .footer-content {
    flex-direction: column;
    gap: 1rem;
  }

  .modal-content {
    padding: 1.5rem;
  }

  .showcase-creds-grid {
    grid-template-columns: 1fr;
  }

  .showcase-metrics-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 480px) {
  .showcase-metrics-grid {
    grid-template-columns: 1fr;
  }
}