/* THEME VARIABLES */
:root {
    --bg-color: #f8f9fa;
    --text-color: #1f2937;
    --muted-text: #4b5563;
    --border-color: #e5e7eb;
    --accent-color: #2563eb;
    --card-bg: #ffffff;
  }
  
  /* DARK MODE */
  html[data-theme="dark"] {
    --bg-color: #0f172a;
    --text-color: #e5e7eb;
    --muted-text: #9ca3af;
    --border-color: #1e293b;
    --accent-color: #60a5fa;
    --card-bg: #020617;
  }
  
  /* RESET */
  *,
  *::before,
  *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
  }
  
  html {
    scroll-behavior: smooth;
  }
  
  body {
    font-family: system-ui, -apple-system, BlinkMacSystemFont,
                 "Segoe UI", Roboto, sans-serif;
    line-height: 1.6;
    font-size: 16px;
    background: var(--bg-color);
    color: var(--text-color);
  }
  
  /* GLOBAL ELEMENTS */
  h1, h2, h3 {
    line-height: 1.3;
  }
  
  h2 {
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
  }
  
  p {
    max-width: 100%;
  }
  
  /* LINKS */
  a {
    color: var(--accent-color);
    text-decoration: none;
    transition: color 0.2s ease;
  }
  
  a:hover {
    text-decoration: underline;
  }
  
  /* LAYOUT */
  .section {
    max-width: 1000px;
    margin: 0 auto;
    padding: 4rem 1.5rem;
  }
  
  /* NAVBAR */
  .site-header {
    position: sticky;
    top: 0;
    background: var(--card-bg);
    border-bottom: 1px solid var(--border-color);
    z-index: 100;
    backdrop-filter: blur(10px);
  }
  
  .navbar {
    max-width: 1000px;
    margin: 0 auto;
    padding: 1rem 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
  }
  
  .nav-brand {
    display: flex;
    flex-direction: column;
  }
  
  .brand-name {
    font-weight: 600;
  }
  
  .brand-tagline {
    font-size: 0.8rem;
    color: var(--muted-text);
  }
  
  #theme-toggle {
    background: none;
    border: none;
    font-size: 1.2rem;
    cursor: pointer;
  }
  
  /* HERO */
  .hero {
    text-align: center;
    padding-top: 5rem;
  }
  
  .profile-photo {
    width: 220px;
    height: 220px;
    border-radius: 50%;
    object-fit: cover;
    margin-bottom: 1.5rem;
    border: 3px solid var(--border-color);
  }
  
  .hero-name {
    font-size: 2.4rem;
    font-weight: 700;
  }
  
  .hero-role {
    margin-top: 0.5rem;
    font-size: 1rem;
    color: var(--muted-text);
  }
  
  .hero-subtitle {
    margin-top: 0.75rem;
    font-size: 0.95rem;
    color: var(--muted-text);
  }
  
  .hero-actions {
    margin-top: 2rem;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 1rem;
  }
  
  /* BUTTONS */
  .btn {
    padding: 0.6rem 1.2rem;
    border: 1px solid var(--text-color);
    text-decoration: none;
    color: var(--text-color);
    font-size: 0.9rem;
    border-radius: 6px;
    background: transparent;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition:
      background 0.2s ease,
      color 0.2s ease,
      transform 0.15s ease,
      border-color 0.2s ease;
  }
  
  .btn:hover {
    background: var(--text-color);
    color: #ffffff;
    transform: translateY(-2px);
  }
  
  .btn:active {
    transform: translateY(0);
  }
  
  /* ABOUT */
  .about p {
    color: var(--muted-text);
  }
  
  /* TECH STACK */
  .tech-stack .stack-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1.5rem;
  }
  
  .stack-item {
    border: 1px solid var(--border-color);
    padding: 1.2rem;
    border-radius: 8px;
    background: var(--card-bg);
    transition:
      transform 0.25s ease,
      box-shadow 0.25s ease,
      background 0.25s ease,
      border-color 0.25s ease;
  }
  
  .stack-item h3 {
    margin-bottom: 0.5rem;
    font-size: 1rem;
  }
  
  .stack-note {
    margin-top: 0.5rem;
    font-size: 0.85rem;
    color: var(--muted-text);
  }
  
  /* PROJECTS */
  .section-intro {
    margin-bottom: 1.5rem;
    color: var(--muted-text);
  }
  
  .project-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 2rem;
  }
  
  .project-card {
    border: 1px solid var(--border-color);
    padding: 1.5rem;
    border-radius: 10px;
    background: var(--card-bg);
    transition:
      transform 0.25s ease,
      box-shadow 0.25s ease,
      background 0.25s ease,
      border-color 0.25s ease;
  }
  
  .project-card h3 {
    margin-bottom: 0.5rem;
  }
  
  .project-tagline {
    font-size: 0.85rem;
    color: var(--muted-text);
    margin-bottom: 0.75rem;
  }
  
  .project-link {
    display: inline-block;
    margin-top: 1rem;
    font-size: 0.9rem;
  }
  
  /* ACADEMIC & EXPLORATION */
  .academic-links {
    margin-top: 1rem;
    list-style: none;
  }
  
  .academic-links li {
    margin-bottom: 0.5rem;
  }
  
  .exploration ul {
    margin-top: 1rem;
    padding-left: 1.2rem;
  }
  
  .exploration li {
    margin-bottom: 0.5rem;
  }
  
  /* FOOTER */
  .site-footer {
    text-align: center;
    padding: 2rem 1rem;
    font-size: 0.85rem;
    color: var(--muted-text);
    max-width: 100%;
  }

  .site-footer p {
    max-width: 100%;
    margin: 0 auto;
  }
  /* HOVER CARDS */
  .stack-item:hover,
  .project-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.08);
  }
  
  /* THEME TRANSITION */
  body,
  .site-header,
  .stack-item,
  .project-card {
    transition:
      background-color 0.3s ease,
      color 0.3s ease,
      border-color 0.3s ease;
  }
  
  /* REVEAL ON LOAD */
  .section {
    opacity: 0;
    transform: translateY(20px);
    animation: fadeUp 0.6s ease forwards;
  }
  
  .section:nth-of-type(1) { animation-delay: 0.1s; }
  .section:nth-of-type(2) { animation-delay: 0.2s; }
  .section:nth-of-type(3) { animation-delay: 0.3s; }
  .section:nth-of-type(4) { animation-delay: 0.4s; }
  .section:nth-of-type(5) { animation-delay: 0.5s; }
  
  @keyframes fadeUp {
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }
  
  /* RESPONSIVE */
  @media (max-width: 640px) {
    .hero-name {
      font-size: 2rem;
    }
  
    .navbar {
      padding-inline: 1rem;
    }
  
    .section {
      padding-inline: 1.25rem;
    }
  }