/* ========================================
   CSS Custom Properties & Theme System
   ======================================== */
:root {
  /* Light mode (default) — blue accent */
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-card: #ffffff;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --accent: #2563eb;
  --accent-light: #3b82f6;
  --accent-glow: rgba(37, 99, 235, 0.3);
  --accent-bg: rgba(37, 99, 235, 0.08);
  --border: rgba(15, 23, 42, 0.08);
  --card-shadow: 0 1px 3px rgba(0, 0, 0, 0.06), 0 4px 16px rgba(0, 0, 0, 0.04);
  --card-hover-shadow: 0 8px 32px rgba(0, 0, 0, 0.08);
  --nav-bg: rgba(248, 250, 252, 0.85);
  --particle-color: rgba(37, 99, 235, 0.25);
  --particle-line: rgba(37, 99, 235, 0.12);
  --honor-line: #e2e8f0;
}

[data-theme="dark"] {
  /* Dark mode — light blue + purple accent */
  --bg-primary: #0a0e1a;
  --bg-secondary: #111827;
  --bg-card: #151c2e;
  --text-primary: #e2e8f0;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent: #7c3aed;
  --accent-light: #67e8f9;
  --accent-glow: rgba(103, 232, 249, 0.25);
  --accent-bg: rgba(124, 58, 237, 0.12);
  --border: rgba(255, 255, 255, 0.06);
  --card-shadow: 0 1px 3px rgba(0, 0, 0, 0.3), 0 4px 16px rgba(0, 0, 0, 0.2);
  --card-hover-shadow: 0 8px 32px rgba(124, 58, 237, 0.15);
  --nav-bg: rgba(10, 14, 26, 0.85);
  --particle-color: rgba(124, 58, 237, 0.35);
  --particle-line: rgba(103, 232, 249, 0.15);
  --honor-line: #1e293b;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  transition: background 0.4s ease, color 0.4s ease;
}

a {
  color: inherit;
  text-decoration: none;
}

/* ========================================
   Background Canvas
   ======================================== */
#bg-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  pointer-events: none;
}

/* ========================================
   Navigation
   ======================================== */
#navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 2rem;
  background: var(--nav-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  transition: all 0.4s ease;
}

#navbar.scrolled {
  padding: 0.6rem 2rem;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
}

.nav-logo {
  font-size: 1.4rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--accent), var(--accent-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.02em;
}

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

.nav-links a {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: color 0.3s ease;
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: width 0.3s ease;
}

.nav-links a:hover {
  color: var(--text-primary);
}

.nav-links a:hover::after {
  width: 100%;
}

#theme-toggle {
  background: none;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.5rem;
  cursor: pointer;
  color: var(--text-secondary);
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
}

#theme-toggle:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-bg);
}

.icon-moon { display: none; }
[data-theme="dark"] .icon-sun { display: none; }
[data-theme="dark"] .icon-moon { display: block; }

/* ========================================
   Hero Section
   ======================================== */
#hero {
  position: relative;
  z-index: 1;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 2rem;
}

.hero-content {
  max-width: 600px;
}

.hero-photo-wrapper {
  position: relative;
  width: 180px;
  height: 180px;
  margin: 0 auto 2.5rem;
}

.hero-photo {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  overflow: hidden;
  position: relative;
  z-index: 2;
  border: 3px solid var(--accent);
  box-shadow: 0 0 30px var(--accent-glow);
}

.hero-photo img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.photo-placeholder {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-secondary);
  color: var(--accent);
  font-size: 3rem;
  font-weight: 800;
}

.hero-ring {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 210px;
  height: 210px;
  border: 1px solid var(--accent-glow);
  border-radius: 50%;
  transform: translate(-50%, -50%);
  animation: ring-pulse 3s ease-in-out infinite;
}

.hero-ring.ring-2 {
  width: 240px;
  height: 240px;
  animation-delay: 1.5s;
}

@keyframes ring-pulse {
  0%, 100% { opacity: 0.3; transform: translate(-50%, -50%) scale(1); }
  50% { opacity: 0.8; transform: translate(-50%, -50%) scale(1.05); }
}

.hero-name {
  font-size: 3.5rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 0.75rem;
  line-height: 1.1;
}

.reveal-text {
  display: inline-block;
  perspective: 600px;
}

.letter {
  display: inline-block;
  opacity: 0;
  transform: translateY(40px) rotateX(-80deg);
  animation: letter-drop 0.5s cubic-bezier(0.22, 0.61, 0.36, 1) forwards;
}

@keyframes letter-drop {
  to {
    opacity: 1;
    transform: translateY(0) rotateX(0deg);
  }
}

@keyframes reveal {
  to { opacity: 1; transform: translateY(0); }
}

.hero-tagline {
  font-size: 1.25rem;
  color: var(--text-secondary);
  font-weight: 400;
  min-height: 1.8em;
}

.typing-cursor {
  animation: blink 0.8s step-end infinite;
  color: var(--accent);
  font-weight: 300;
}

@keyframes blink {
  50% { opacity: 0; }
}

.hero-scroll-hint {
  margin-top: 3rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-muted);
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  opacity: 0;
  animation: reveal 0.8s ease forwards 1.5s;
}

.scroll-arrow {
  width: 20px;
  height: 20px;
  border-right: 2px solid var(--text-muted);
  border-bottom: 2px solid var(--text-muted);
  transform: rotate(45deg);
  animation: scroll-bounce 2s ease-in-out infinite;
}

@keyframes scroll-bounce {
  0%, 100% { transform: rotate(45deg) translate(0, 0); opacity: 0.5; }
  50% { transform: rotate(45deg) translate(4px, 4px); opacity: 1; }
}

/* ========================================
   Sections
   ======================================== */
.section {
  position: relative;
  z-index: 1;
  padding: 6rem 2rem;
}

#bio.section {
  padding-top: 1rem;
}

.container {
  max-width: 1000px;
  margin: 0 auto;
}

.section-title {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 3rem;
  letter-spacing: -0.02em;
}

.title-accent {
  color: var(--accent);
  font-family: 'JetBrains Mono', monospace;
  font-weight: 500;
  margin-right: 0.5rem;
}

/* Fade-up animation */
.fade-up {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.fade-up.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ========================================
   Bio Section
   ======================================== */
.bio-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 3rem;
  position: relative;
  overflow: hidden;
}

.bio-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--accent), var(--accent-light), var(--accent));
  background-size: 200% 100%;
  animation: gradient-slide 3s ease infinite;
}

@keyframes gradient-slide {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

.bio-text {
  margin-bottom: 2.5rem;
}

.bio-text p {
  font-size: 1.1rem;
  color: var(--text-secondary);
  line-height: 1.9;
  margin-bottom: 1rem;
}

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

.bio-stats {
  display: flex;
  gap: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
}

.stat-item {
  text-align: center;
}

.stat-number {
  display: block;
  font-size: 2.5rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--accent), var(--accent-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.2;
}

.stat-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-weight: 500;
}

/* ========================================
   Extra Animations
   ======================================== */
/* Slide in from left */
.slide-left {
  opacity: 0;
  transform: translateX(-60px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.slide-left.visible {
  opacity: 1;
  transform: translateX(0);
}

/* Slide in from right */
.slide-right {
  opacity: 0;
  transform: translateX(60px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.slide-right.visible {
  opacity: 1;
  transform: translateX(0);
}

/* Scale up */
.scale-up {
  opacity: 0;
  transform: scale(0.85);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.scale-up.visible {
  opacity: 1;
  transform: scale(1);
}

/* Glow pulse on nav-logo */
.nav-logo {
  animation: logo-glow 3s ease-in-out infinite alternate;
}

@keyframes logo-glow {
  from { filter: drop-shadow(0 0 0px transparent); }
  to { filter: drop-shadow(0 0 8px var(--accent-glow)); }
}

/* Stagger children animation */
.stagger-children > * {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.3s ease, transform 0.3s ease;
}

.stagger-children.visible > *:nth-child(1) { transition-delay: 0s; }
.stagger-children.visible > *:nth-child(2) { transition-delay: 0.03s; }
.stagger-children.visible > *:nth-child(3) { transition-delay: 0.06s; }
.stagger-children.visible > *:nth-child(4) { transition-delay: 0.09s; }
.stagger-children.visible > *:nth-child(5) { transition-delay: 0.11s; }

.stagger-children.visible > * {
  opacity: 1;
  transform: translateY(0);
}

/* Status Banner */
.status-banner {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.875rem 1.25rem;
  background: var(--accent-bg);
  border: 1px solid var(--accent-glow);
  border-radius: 12px;
  margin-bottom: 1.5rem;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-primary);
}

.status-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #22c55e;
  flex-shrink: 0;
  animation: status-pulse 2s ease-in-out infinite;
}

@keyframes status-pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(34, 197, 94, 0.5); }
  50% { box-shadow: 0 0 0 6px rgba(34, 197, 94, 0); }
}

/* Active nav link */
.nav-links a.active {
  color: var(--accent);
}

.nav-links a.active::after {
  width: 100%;
}

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

.about-text p {
  font-size: 1.1rem;
  color: var(--text-secondary);
  line-height: 1.8;
}

.currently-doing h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
  color: var(--accent);
  font-family: 'JetBrains Mono', monospace;
}

.current-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.current-list li {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  padding: 1rem;
  border-radius: 12px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  transition: all 0.3s ease;
}

.current-list li:hover {
  border-color: var(--accent-glow);
  box-shadow: 0 4px 20px var(--accent-glow);
  transform: translateX(4px);
}

.current-icon {
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 10px;
  background: var(--accent-bg);
  color: var(--accent);
}

.current-list li strong {
  display: block;
  margin-bottom: 0.2rem;
  font-weight: 600;
}

.current-list li p {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

/* ========================================
   Projects Section
   ======================================== */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}

.project-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  transition: all 0.4s ease;
  position: relative;
  overflow: hidden;
  cursor: pointer;
  text-decoration: none;
  color: inherit;
  display: flex;
  flex-direction: column;
}

.project-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), var(--accent-light));
  opacity: 0;
  transition: opacity 0.3s ease;
  z-index: 2;
}

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

.project-card:hover::before {
  opacity: 1;
}

.project-card:hover .project-image img {
  transform: scale(1.05);
}

.project-card:hover .project-image-placeholder {
  background: var(--accent-bg);
}

/* Project Image */
.project-image {
  position: relative;
  width: 100%;
  height: 220px;
  overflow: hidden;
  background: var(--bg-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
}

.project-image img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  transition: transform 0.4s ease;
  display: block;
}

.project-image img[src=""],
.project-image img:not([src]) {
  display: none;
}

.project-image-placeholder {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  transition: background 0.3s ease;
}

.project-image-placeholder svg {
  color: var(--text-muted);
  opacity: 0.5;
}

.project-image-placeholder small {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 500;
}

/* Hide placeholder when image loads */
.project-image img.loaded + .project-image-placeholder {
  display: none;
}

.project-body {
  padding: 1.5rem;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.project-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
}

.project-links a {
  color: var(--text-muted);
  transition: color 0.3s ease;
}

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

.project-title {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.project-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 1.25rem;
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.project-tags span {
  font-size: 0.75rem;
  font-weight: 500;
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  background: var(--accent-bg);
  color: var(--accent);
  font-family: 'JetBrains Mono', monospace;
}

/* ========================================
   Honors & Awards Section
   ======================================== */
.honors-timeline {
  position: relative;
  padding-left: 2rem;
}

.honors-timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: linear-gradient(180deg, var(--accent), var(--honor-line));
}

.honor-item {
  position: relative;
  padding: 0 0 2.5rem 2rem;
}

.honor-item::before {
  content: '';
  position: absolute;
  left: -2rem;
  top: 0.5rem;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--accent);
  border: 3px solid var(--bg-primary);
  box-shadow: 0 0 0 3px var(--accent-glow);
  transition: background 0.4s, border-color 0.4s;
}

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

.honor-year {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--accent);
  margin-bottom: 0.4rem;
}

.honor-content h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.3rem;
}

.honor-content p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ========================================
   Contact Section
   ======================================== */
.contact-subtitle {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 2.5rem;
}

.contact-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
}

.contact-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
  padding: 2rem 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  transition: all 0.3s ease;
  text-align: center;
}

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

.contact-card svg {
  color: var(--accent);
}

.contact-card span {
  font-weight: 600;
  font-size: 0.95rem;
}

.contact-card small {
  font-size: 0.8rem;
  color: var(--text-muted);
  word-break: break-all;
}


/* ========================================
   Footer
   ======================================== */
footer {
  position: relative;
  z-index: 1;
  text-align: center;
  padding: 2rem;
  color: var(--text-muted);
  font-size: 0.85rem;
  border-top: 1px solid var(--border);
}

/* ========================================
   Mobile Nav (hamburger)
   ======================================== */
#nav-hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  background: none;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.5rem;
  cursor: pointer;
  width: 38px;
  height: 38px;
  flex-shrink: 0;
}

#nav-hamburger span {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--text-secondary);
  border-radius: 2px;
  transition: transform 0.3s ease, opacity 0.3s ease;
  transform-origin: center;
}

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

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

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

/* ========================================
   Responsive
   ======================================== */
@media (max-width: 768px) {
  .hero-name {
    font-size: 2.5rem;
  }

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

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

  .hero-ring {
    width: 170px;
    height: 170px;
  }

  .hero-ring.ring-2 {
    width: 200px;
    height: 200px;
  }

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

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

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

  .nav-links {
    gap: 1rem;
  }

  .nav-links a {
    font-size: 0.8rem;
  }

  #navbar {
    padding: 0.8rem 1rem;
  }

  .bio-card {
    padding: 2rem;
  }

  .bio-stats {
    gap: 1.5rem;
    flex-wrap: wrap;
    justify-content: center;
  }

  .section-title {
    font-size: 1.6rem;
    margin-bottom: 2rem;
  }
}

@media (max-width: 600px) {
  #nav-hamburger {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--bg-primary);
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 2.5rem;
    z-index: 99;
    transform: translateY(-100%);
    transition: transform 0.4s cubic-bezier(0.22, 0.61, 0.36, 1), visibility 0.4s;
    visibility: hidden;
    pointer-events: none;
  }

  .nav-links.mobile-open {
    transform: translateY(0);
    visibility: visible;
    pointer-events: auto;
  }

  .nav-links a {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
  }

  .nav-links a::after {
    display: none;
  }
}

@media (max-width: 480px) {
  .hero-name {
    font-size: 2rem;
  }

  .hero-tagline {
    font-size: 1rem;
  }

  .section {
    padding: 4rem 1rem;
  }

  .bio-card {
    padding: 1.25rem;
  }

  .bio-stats {
    gap: 1rem;
  }

  .stat-number {
    font-size: 2rem;
  }

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