:root {
  /* Colors - Light Mode (Updated Modern Palette) */
  --bg-body: #FAFAFA;
  --bg-card: #FFFFFF;
  --text-main: #0F172A; /* Slate 900 for more definition */
  --text-muted: #334155; /* Slate 700 - Better contrast */
  --accent: #1D4ED8; /* Blue 700 - AAA contrast */
  --accent-light: #EFF6FF;
  --accent-hover: #1E40AF; /* Blue 800 */
  --border: #CBD5E1; /* Slate 300 */
  --shadow-sm: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
  --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.15), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  
  /* Button specific vars */
  --btn-text: #FFFFFF;

  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-12: 3rem;
  --container-width: 1024px;
  
  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

/* Dark Mode (Deep Blue/Slate) */
[data-theme="dark"] {
  --bg-body: #0F172A; /* Slate 900 */
  --bg-card: #1E293B; /* Slate 800 */
  --text-main: #F8FAFC; /* Slate 50 */
  --text-muted: #CBD5E1; /* Slate 300 */
  --accent: #60A5FA; /* Blue 400 */
  --accent-light: #1e3a8a;
  --accent-hover: #93C5FD;
  --border: #334155;
  --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.5);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.5);
  
  /* Dark text on bright accent button */
  --btn-text: #0F172A;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  background-color: var(--bg-body);
  color: var(--text-main);
  line-height: 1.6;
  transition: background-color 0.3s ease, color 0.3s ease;
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: inherit;
  text-decoration: none;
  transition: color 0.2s;
}

ul {
  list-style: none;
}

/* Utilities */
.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--space-4);
  width: 100%;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.6rem 1.2rem;
  font-weight: 600;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  font-size: 0.95rem;
  border: 1px solid var(--border);
  background-color: var(--bg-card);
  color: var(--text-main);
}

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

.btn:active {
  transform: translateY(0);
}

.btn-primary {
  background-color: var(--accent);
  color: var(--btn-text);
  border-color: var(--accent);
  font-weight: 700; /* Bolder text for better legibility */
}

.btn-primary:hover {
  background-color: var(--accent-hover);
  color: var(--btn-text);
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3); /* Subtle glow */
}

/* Section styling with more breathing room */
.section {
  padding: var(--space-12) 0;
}

.section-title {
  font-size: 1.8rem;
  font-weight: 800;
  margin-bottom: var(--space-8);
  color: var(--text-main);
  position: relative;
  display: inline-block;
  letter-spacing: -0.02em;
}

.section-title::after {
  content: '';
  display: block;
  width: 100%;
  height: 4px;
  background: var(--accent);
  margin-top: 4px;
  border-radius: 2px;
  opacity: 0.8;
}

.tag {
  display: inline-block;
  padding: 4px 10px;
  background-color: var(--bg-body);
  border: 1px solid var(--border);
  border-radius: 20px; /* Pill shape */
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: all 0.2s;
}

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

/* Header - Glassmorphism */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(255, 255, 255, 0.8); /* Semi-transparent */
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: var(--space-3) 0;
  transition: background-color 0.3s;
}

[data-theme="dark"] .header {
  background-color: rgba(15, 23, 42, 0.8);
}

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

.logo {
  font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
  font-weight: 800;
  font-size: 1.5rem;
  letter-spacing: -0.5px;
  color: var(--accent);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.logo:hover {
  transform: scale(1.05);
  text-shadow: 0 4px 12px rgba(37, 99, 235, 0.25);
}

.nav {
  display: flex;
  gap: var(--space-6);
  align-items: center;
}

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

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

/* Hero Section */
.hero {
  padding: 8rem 0 6rem;
  background: radial-gradient(circle at 100% 0%, var(--accent-light) 0%, transparent 25%), 
              radial-gradient(circle at 0% 100%, var(--accent-light) 0%, transparent 25%);
}

[data-theme="dark"] .hero {
  background: radial-gradient(circle at 100% 0%, rgba(59, 130, 246, 0.1) 0%, transparent 30%);
}

.hero h1 {
  font-size: clamp(2.5rem, 5vw, 4rem); /* Responsive font size */
  font-weight: 900;
  margin-bottom: var(--space-4);
  line-height: 1.1;
  letter-spacing: -0.03em;
  background: linear-gradient(to right, var(--text-main), var(--text-muted));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent; /* Gradient text effect */
  background-clip: text;
  color: var(--text-main); /* Fallback */
}

/* Allow gradient to work, override fallback if needed */
.hero h1 {
    color: var(--text-main);
    -webkit-text-fill-color: var(--text-main);
}

.hero p {
  font-size: 1.25rem;
  color: var(--text-muted);
  margin-bottom: var(--space-8);
  max-width: 800px;
  line-height: 1.6;
}

.hero-buttons {
  display: flex;
  gap: var(--space-4);
  flex-wrap: wrap;
}

/* Skills */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-6);
}

.skill-category {
  background: var(--bg-card);
  padding: var(--space-4);
  border-radius: 12px;
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  transition: transform 0.2s;
}

.skill-category:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}

.skill-category h3 {
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  margin-bottom: var(--space-4);
  font-weight: 700;
}

.skill-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

/* Projects Cards - Improved */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--space-6);
}

.project-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: var(--space-6);
  box-shadow: var(--shadow-sm);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  display: flex;
  flex-direction: column;
  height: 100%;
}

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

.project-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-3);
}

.project-title {
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--text-main);
}

.project-year {
  font-size: 0.8rem;
  font-weight: 600;
  padding: 2px 8px;
  background: var(--bg-body);
  border-radius: 12px;
  color: var(--text-muted);
}

.project-desc {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: var(--space-4);
  flex-grow: 1;
  line-height: 1.6;
}

.project-tech {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: var(--space-6);
}

.project-links {
  display: flex;
  gap: var(--space-4);
  margin-top: auto;
  border-top: 1px solid var(--border);
  padding-top: var(--space-4);
}

.project-link {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--accent);
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.project-link:hover {
  text-decoration: underline;
}

/* Experience */
.experience-item {
  border-left: 2px solid var(--border);
  padding-left: var(--space-6);
  padding-bottom: var(--space-6);
  margin-bottom: 0;
  position: relative;
}

.experience-item::before {
  content: '';
  position: absolute;
  left: -5px; /* (2px width / 2) - (8px width / 2) approx */
  top: 0;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: var(--accent);
  border: 4px solid var(--bg-body);
  box-sizing: content-box; /* To add border outside width */
  margin-left: -5px; /* Center with line */
}

.exp-header {
  margin-bottom: var(--space-2);
}

.exp-role {
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--text-main);
}

.exp-company {
  color: var(--accent);
  font-weight: 600;
  font-size: 1rem;
}

.exp-time {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: var(--space-2);
  display: block;
}

/* Contact Items */
.contact-item { 
    display: flex; 
    align-items: center; 
    gap: var(--space-3); 
    margin-bottom: var(--space-3); 
    padding: var(--space-2) 0;
}
.contact-label { 
    font-weight: 600; 
    min-width: 80px; 
    color: var(--text-muted);
}
.contact-link { 
    color: var(--accent); 
    font-weight: 500;
}
.contact-link:hover { 
    text-decoration: underline; 
}
.copy-btn { 
    background: var(--bg-body); 
    border: 1px solid var(--border); 
    cursor: pointer; 
    padding: 6px; 
    border-radius: 6px;
    display: inline-flex; 
    color: var(--text-muted); 
    transition: all 0.2s; 
}
.copy-btn:hover { 
    background-color: var(--accent-light); 
    color: var(--accent); 
    border-color: var(--accent);
}

/* Footer */
.footer {
  border-top: 1px solid var(--border);
  padding: var(--space-8) 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-top: var(--space-12);
  background-color: var(--bg-body);
}

/* Mobile */
.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  padding: var(--space-2);
  cursor: pointer;
  color: var(--text-main);
}

@media (max-width: 768px) {
  .hero { padding: 4rem 0; }
  .hero h1 { font-size: 2.5rem; }
  
  .nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background-color: var(--bg-card);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: var(--space-4);
    box-shadow: var(--shadow-lg);
  }

  .nav.active {
    display: flex;
  }

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



/* Active Nav Link */
.nav-link.active {
  color: var(--accent);
  font-weight: 700;
}

.nav-link.active::after {
  content: '';
  display: block;
  width: 100%;
  height: 2px;
  background-color: var(--accent);
  position: absolute;
  bottom: -4px;
  left: 0;
}

/* Skeleton Loading Animation */
.skeleton {
  background-color: var(--border);
  background-image: linear-gradient(
    90deg,
    rgba(255, 255, 255, 0) 0,
    rgba(255, 255, 255, 0.4) 50%,
    rgba(255, 255, 255, 0) 100%
  );
  background-size: 200% 100%;
  background-repeat: no-repeat;
  background-position: -150% 0;
  animation: shimmer 1.5s infinite linear;
  border-radius: 4px;
  display: inline-block;
}

[data-theme='dark'] .skeleton {
    background-color: var(--bg-card);
    background-image: linear-gradient(
    90deg,
    rgba(255, 255, 255, 0) 0,
    rgba(255, 255, 255, 0.05) 50%,
    rgba(255, 255, 255, 0) 100%
  );
}

@keyframes shimmer {
  to {
    background-position: 150% 0;
  }
}

.skeleton-text {
  height: 1em;
  margin-bottom: 0.5rem;
  width: 100%;
}

.skeleton-title {
  height: 2rem;
  margin-bottom: 1rem;
  width: 60%;
}

.skeleton-card {
  height: 200px;
  width: 100%;
  border-radius: 8px;
}


/* Mobile Optimizations (Overrides) */
@media (max-width: 768px) {
  .hero { 
    padding: 3rem 0 !important;
  }
  
  .hero h1 { 
    font-size: 2rem !important;
  }
  
  .section {
    padding: var(--space-8) 0 !important;
  }

  .nav {
    gap: 0 !important;
  }

  .mobile-menu-btn {
    padding: 12px !important;
  }

  /* Improved Touch Targets */
  .nav-link {
    display: block;
    padding: 16px 0 !important;
    font-size: 1.1rem;
    border-bottom: 1px solid var(--border);
    width: 100%;
  }

  .btn {
    width: 100%;
    margin-bottom: 10px;
    padding: 14px !important;
  }

  .hero-buttons {
    flex-direction: column;
    width: 100%;
  }

  .project-links {
    flex-direction: column;
    gap: var(--space-3);
  }
  
  .project-link {
    padding: 12px;
    background: var(--bg-body);
    border-radius: 6px;
    justify-content: center;
    border: 1px solid var(--border);
  }
}