header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  width: 100%;
  z-index: 1000;
  background: rgba(26, 26, 26, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255, 107, 53, 0.1);
  transition: var(--transition-normal);
  will-change: background, box-shadow;
}

header.scrolled {
  background: rgba(26, 26, 26, 0.98);
  box-shadow: var(--shadow-lg);
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
  min-height: var(--header-height);
}

.logo {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  background: linear-gradient(135deg, var(--primary-orange), var(--secondary-orange));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  transition: var(--transition-normal);
  will-change: transform;
}

.logo:hover {
  transform: scale(1.05);
}

.nav {
  display: flex;
  align-items: center;
  margin-left: 44%;
  gap: var(--spacing-xl);
  transition: none;
}

.nav-link {
  color: var(--text-gray);
  font-weight: 500;
  position: relative;
  transition: var(--transition-normal);
  will-change: color;
}

.nav-link::after {
  content: '';
  position: absolute;
  width: 0;
  height: 2px;
  bottom: -5px;
  left: 50%;
  background: linear-gradient(135deg, var(--primary-orange), var(--secondary-orange));
  transition: var(--transition-normal);
  transform: translateX(-50%);
}

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

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

.mobile-menu-toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  padding: var(--spacing-sm);
  color: var(--text-light);
}

.mobile-menu-toggle span {
  width: 25px;
  height: 3px;
  background: var(--primary-orange);
  transition: var(--transition-fast);
}

@media (max-width: 768px) {
  .nav {
    position: fixed;
    top: var(--header-height);
    left: -100%;
    width: 100%;
    height: calc(100vh - var(--header-height));
    background: rgba(26, 26, 26, 0.98);
    backdrop-filter: blur(10px);
    flex-direction: column;
    justify-content: flex-start;
    align-items: center;
    padding-top: var(--spacing-3xl);
    transition: left 0.3s ease;
    z-index: 999;
    margin-left: 0;
    overflow-y: auto;
    visibility: hidden;
  }

  .nav.open {
    left: 0;
    visibility: visible;
  }

  .nav-link {
    font-size: var(--font-size-lg);
    padding: var(--spacing-md) 0;
    width: 100%;
    text-align: center;
  }

  .mobile-menu-toggle {
    display: flex;
    background: none;
    border: none;
    cursor: pointer;
    z-index: 1001;
  }

  .mobile-menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
  }

  .mobile-menu-toggle.active span:nth-child(2) {
    opacity: 0;
  }

  .mobile-menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -7px);
  }
}