:root {
      --primary: #0a66c2;
      --primary-dark: #004182;
      --secondary: #00d2ff;
      --bg: #f8f9fa;
      --text: #333333;
      --text-light: #666666;
      --card-bg: #ffffff;
      --shadow: 0 5px 15px rgba(0,0,0,0.08);
      --transition: all 0.3s ease;
      --nav-height: 70px;
    }

    body.dark {
      --bg: #0f172a;
      --text: #e2e8f0;
      --text-light: #94a3b8;
      --card-bg: #1e293b;
      --shadow: 0 5px 15px rgba(0,0,0,0.3);
    }

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
      font-family: "Poppins", sans-serif;
      scroll-behavior: smooth;
    }

    body {
      background: var(--bg);
      color: var(--text);
      line-height: 1.6;
      transition: background-color 0.3s, color 0.3s;
      overflow-x: hidden;
    }

    /* --- Navigation --- */
    nav {
      position: fixed;
      width: 100%;
      top: 0;
      height: var(--nav-height);
      background: rgba(255, 255, 255, 0.9);
      backdrop-filter: blur(10px);
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 0 5%;
      box-shadow: 0 2px 10px rgba(0,0,0,0.05);
      z-index: 1000;
      transition: background 0.3s;
    }

    body.dark nav {
      background: rgba(30, 41, 59, 0.9);
    }

    .logo {
      font-size: 1.5rem;
      font-weight: 700;
      color: var(--primary);
      text-decoration: none;
    }

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

    .nav-links li a {
      margin: 0 15px;
      text-decoration: none;
      color: var(--text);
      font-weight: 500;
      position: relative;
      transition: var(--transition);
    }

    .nav-links li a::after {
      content: '';
      position: absolute;
      width: 0;
      height: 2px;
      bottom: -5px;
      left: 0;
      background-color: var(--primary);
      transition: var(--transition);
    }

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

    #themeToggle {
      background: none;
      border: none;
      font-size: 1.2rem;
      cursor: pointer;
      color: var(--text);
      margin-left: 20px;
      transition: transform 0.3s;
    }

    #themeToggle:hover {
      transform: rotate(15deg);
    }

    .hamburger {
      display: none;
      cursor: pointer;
      font-size: 1.5rem;
      color: var(--text);
    }

    /* --- Hero Section --- */
    .hero {
      height: 100vh;
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      text-align: center;
      padding: 0 20px;
      background: radial-gradient(circle at top right, rgba(10, 102, 194, 0.1), transparent 40%),
                  radial-gradient(circle at bottom left, rgba(0, 210, 255, 0.1), transparent 40%);
    }

    .hero h1 {
      font-size: 3.5rem;
      margin-bottom: 10px;
      background: linear-gradient(135deg, var(--primary), var(--secondary));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      animation: fadeInDown 1s ease;
    }

    .hero p {
      font-size: 1.2rem;
      color: var(--text-light);
      margin-bottom: 30px;
      animation: fadeInUp 1s ease 0.2s backwards;
    }

    .btn {
      padding: 12px 30px;
      background: var(--primary);
      color: white;
      text-decoration: none;
      border-radius: 50px;
      font-weight: 600;
      box-shadow: 0 4px 15px rgba(10, 102, 194, 0.3);
      transition: var(--transition);
      display: inline-flex;
      align-items: center;
      gap: 10px;
      border: 2px solid transparent;
      animation: fadeInUp 1s ease 0.4s backwards;
    }

    .btn:hover {
      background: transparent;
      border-color: var(--primary);
      color: var(--primary);
      transform: translateY(-3px);
    }

    /* --- Common Section Styles --- */
    section {
      padding: 100px 5%;
      max-width: 1200px;
      margin: auto;
    }

    .section-title {
      text-align: center;
      font-size: 2rem;
      margin-bottom: 60px;
      position: relative;
    }

    .section-title::after {
      content: '';
      display: block;
      width: 60px;
      height: 4px;
      background: var(--primary);
      margin: 10px auto 0;
      border-radius: 2px;
    }

    /* --- Animation Classes --- */
    .reveal {
      opacity: 0;
      transform: translateY(30px);
      transition: all 0.8s ease;
    }

    .reveal.active {
      opacity: 1;
      transform: translateY(0);
    }

    /* --- About Section --- */
    #about p {
      max-width: 700px;
      margin: 0 auto;
      text-align: center;
      font-size: 1.1rem;
      color: var(--text-light);
    }

    /* --- Skills Section --- */
    .skills-container {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      gap: 20px;
    }

    .skill-item {
      background: var(--card-bg);
      padding: 15px 25px;
      border-radius: 12px;
      box-shadow: var(--shadow);
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 500;
      transition: var(--transition);
      border: 1px solid transparent;
    }

    .skill-item i {
      font-size: 1.2rem;
      color: var(--primary);
    }

    .skill-item:hover {
      transform: translateY(-5px);
      border-color: var(--primary);
    }

    /* --- Projects Section --- */
    .projects-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
      gap: 30px;
    }

    .project-card {
      background: var(--card-bg);
      border-radius: 15px;
      overflow: hidden;
      box-shadow: var(--shadow);
      transition: var(--transition);
      display: flex;
      flex-direction: column;
    }

    .project-card:hover {
      transform: translateY(-10px);
      box-shadow: 0 15px 30px rgba(0,0,0,0.15);
    }

    .project-img {
      width: 100%;
      height: 180px;
      object-fit: cover;
      background-color: #ddd;
    }

    .project-content {
      padding: 20px;
      flex-grow: 1;
      display: flex;
      flex-direction: column;
    }

    .project-content h3 {
      margin-bottom: 10px;
      font-size: 1.25rem;
    }

    .project-content p {
      color: var(--text-light);
      font-size: 0.95rem;
      margin-bottom: 20px;
      flex-grow: 1;
    }

    .project-link {
      text-decoration: none;
      color: var(--primary);
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      gap: 5px;
      transition: gap 0.2s;
    }

    .project-link:hover {
      gap: 10px;
    }

    /* --- Contact Section --- */
    .contact-container {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 50px;
      background: var(--card-bg);
      padding: 40px;
      border-radius: 20px;
      box-shadow: var(--shadow);
    }

    .contact-info h3 {
      margin-bottom: 20px;
      font-size: 1.5rem;
    }

    .info-item {
      display: flex;
      align-items: center;
      gap: 15px;
      margin-bottom: 20px;
      color: var(--text-light);
    }

    .info-item i {
      color: var(--primary);
      font-size: 1.2rem;
    }

    .info-item a {
      color: var(--text);
      text-decoration: none;
      transition: color 0.3s;
    }

    .info-item a:hover {
      color: var(--primary);
    }

    .social-links {
      margin-top: 30px;
      display: flex;
      gap: 15px;
    }

    .social-btn {
      width: 40px;
      height: 40px;
      border-radius: 50%;
      background: var(--bg);
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--text);
      text-decoration: none;
      transition: var(--transition);
      border: 1px solid #ddd;
    }

    .social-btn:hover {
      background: var(--primary);
      color: white;
      border-color: var(--primary);
    }

    .contact-form {
      display: flex;
      flex-direction: column;
      gap: 15px;
    }

    .form-group input, 
    .form-group textarea {
      width: 100%;
      padding: 15px;
      border-radius: 8px;
      border: 1px solid #ddd;
      background: var(--bg);
      color: var(--text);
      font-family: inherit;
      outline: none;
      transition: border-color 0.3s;
    }

    .form-group input:focus, 
    .form-group textarea:focus {
      border-color: var(--primary);
    }

    .submit-btn {
      background: var(--primary);
      color: white;
      border: none;
      padding: 12px;
      border-radius: 8px;
      cursor: pointer;
      font-weight: 600;
      transition: background 0.3s;
    }

    .submit-btn:hover {
      background: var(--primary-dark);
    }

    /* --- Footer --- */
    footer {
      text-align: center;
      padding: 30px;
      background: var(--card-bg);
      border-top: 1px solid #eee;
      color: var(--text-light);
      margin-top: 50px;
    }

    /* --- Scroll Top --- */
    #scrollTop {
      position: fixed;
      bottom: 30px;
      right: 30px;
      width: 45px;
      height: 45px;
      font-size: 20px;
      border: none;
      background: var(--primary);
      color: white;
      border-radius: 50%;
      cursor: pointer;
      display: none;
      align-items: center;
      justify-content: center;
      box-shadow: 0 4px 10px rgba(0,0,0,0.2);
      transition: transform 0.3s;
      z-index: 999;
    }

    #scrollTop:hover {
      transform: translateY(-5px);
    }

    /* --- Toast Notification --- */
    .toast {
      position: fixed;
      bottom: 30px;
      left: 50%;
      transform: translateX(-50%) translateY(100px);
      background: #333;
      color: white;
      padding: 12px 25px;
      border-radius: 30px;
      box-shadow: 0 5px 15px rgba(0,0,0,0.2);
      opacity: 0;
      transition: all 0.4s ease;
      z-index: 2000;
    }
    
    .toast.show {
      transform: translateX(-50%) translateY(0);
      opacity: 1;
    }

    /* --- Animations --- */
    @keyframes fadeInDown {
      from { opacity: 0; transform: translateY(-30px); }
      to { opacity: 1; transform: translateY(0); }
    }
    
    @keyframes fadeInUp {
      from { opacity: 0; transform: translateY(30px); }
      to { opacity: 1; transform: translateY(0); }
    }

    /* --- Responsive --- */
    @media (max-width: 768px) {
      .hero h1 { font-size: 2.5rem; }
      
      .hamburger { display: block; }
      
      .nav-links {
        position: fixed;
        top: var(--nav-height);
        right: -100%;
        width: 100%;
        height: calc(100vh - var(--nav-height));
        background: var(--card-bg);
        flex-direction: column;
        justify-content: center;
        transition: 0.4s ease;
        box-shadow: -5px 0 15px rgba(0,0,0,0.1);
      }

      .nav-links.active { right: 0; }
      .nav-links li { margin: 20px 0; }
      
      .contact-container {
        grid-template-columns: 1fr;
        padding: 25px;
      }
    }