.portfolio-header {
    background: #1a1a1a;
    color: #fff;
    padding: 0.8rem 0;
    font-family: 'Open Sans', sans-serif;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
    box-sizing: border-box;
  }
  
  .header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
  }
  
  .header-brand .logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: #fff;
    text-decoration: none;
    transition: opacity 0.3s;
  }
  
  .header-brand .logo:hover {
    opacity: 0.8;
  }
  
  .nav-links {
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
    gap: 2rem;
  }
  
  .nav-links a {
    color: #ddd;
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
    position: relative;
    transition: all 0.3s;
  }
  
  .nav-links a::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: -5px;
    width: 0;
    height: 2px;
    background: #4e9af1;
    transition: width 0.3s;
  }
  
  .nav-links a:hover {
    color: #fff;
  }
  
  .nav-links a:hover::after {
    width: 100%;
  }
  
  .header-social {
    display: flex;
    gap: 1rem;
  }
  
  .social-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.1);
    transition: all 0.3s ease;
  }
  
  .social-link:hover {
    background: #4e9af1;
    transform: translateY(-3px);
  }
  
  .menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
  }
  
  .menu-toggle span {
    display: block;
    width: 25px;
    height: 3px;
    background: #fff;
    margin: 5px 0;
    transition: all 0.3s;
  }
  
  /* Responsive */
  @media (max-width: 768px) {
    .portfolio-header {
        padding: 1rem 0;
    }

    .nav-links {
      position: fixed;
      top: 70px;
      left: 0;
      width: 100%;
      background: #111;
      flex-direction: column;
      align-items: center;
      padding: 2rem 0;
      gap: 1.5rem;
      transform: translateY(-150%);
      transition: transform 0.3s ease;
      box-shadow: 0 10px 10px rgba(0, 0, 0, 0.2);
    }
    
    .nav-links.active {
      transform: translateY(0);
    }
    
    .header-social {
      display: none;
    }
    
    .menu-toggle {
      display: block;
    }
    
    .menu-toggle.active span:nth-child(1) {
      transform: translateY(8px) rotate(45deg);
    }
    
    .menu-toggle.active span:nth-child(2) {
      opacity: 0;
    }
    
    .menu-toggle.active span:nth-child(3) {
      transform: translateY(-8px) rotate(-45deg);
    }
  }