/* Navigation Bar Styles */

/* Fixed header at top of viewport */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  width: 100%;
  height: var(--header-height);
  background-color: var(--color-white);
  border-bottom: 1px solid var(--color-warm-grey-light);
  z-index: var(--z-fixed);
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--max-content-width);
  margin: 0 auto;
  padding: 0 var(--space-md);
}

/* Brand section */
.brand {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.brand h1 {
  font-family: var(--font-primary);
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-light);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-dark-grey);
  margin: 0;
  line-height: var(--line-height-tight);
}

.brand .tagline {
  font-family: var(--font-primary);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-light);
  color: var(--color-medium-grey);
  margin: 0;
  line-height: var(--line-height-tight);
}

/* Burger menu button - visible on mobile/tablet */
.burger-menu {
  display: flex;
  flex-direction: column;
  justify-content: space-around;
  width: 44px;
  height: 44px;
  min-width: 44px;
  min-height: 44px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: var(--space-sm);
  z-index: calc(var(--z-fixed) + 1);
}

.burger-menu span {
  width: 100%;
  height: 2px;
  background-color: var(--color-dark-grey);
  transition: all var(--transition-normal);
  transform-origin: center;
}

.burger-menu:hover span {
  background-color: var(--color-warm-grey-dark);
}

.burger-menu:focus {
  outline: 2px solid var(--color-black);
  outline-offset: 2px;
}

/* Navigation menu - mobile/tablet styles (default) */
.main-nav {
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  background-color: var(--color-white);
  border-bottom: 1px solid var(--color-warm-grey-light);
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-normal);
}

.main-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
}

.main-nav li {
  border-bottom: 1px solid var(--color-warm-grey-light);
}

.main-nav li:last-child {
  border-bottom: none;
}

.main-nav a {
  display: flex;
  align-items: center;
  padding: var(--space-md);
  font-family: var(--font-primary);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-light);
  letter-spacing: 0.05em;
  text-transform: uppercase;
  text-decoration: none;
  color: var(--color-dark-grey);
  transition: all var(--transition-fast);
  min-height: 44px;
}

.main-nav a:hover {
  background-color: var(--color-warm-grey-light);
  color: var(--color-black);
}

.main-nav a:focus {
  outline: 2px solid var(--color-black);
  outline-offset: 2px;
}

/* Active page indicator */
.main-nav a.active {
  font-weight: var(--font-weight-medium);
  color: var(--color-black);
  background-color: var(--color-warm-grey-light);
}

/* Open state for mobile menu */
body.nav-open .main-nav {
  max-height: 300px;
}

/* Burger menu animation when open */
body.nav-open .burger-menu span:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}

body.nav-open .burger-menu span:nth-child(2) {
  opacity: 0;
}

body.nav-open .burger-menu span:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

/* Tablet styles (768px and up) */
@media (width >= 768px) {
  .header-container {
    padding: 0 var(--space-lg);
  }
  
  .brand h1 {
    font-size: var(--font-size-2xl);
  }
  
  .brand .tagline {
    font-size: var(--font-size-sm);
  }
}

/* Desktop styles (1024px and up) */
@media (width >= 1024px) {
  .header-container {
    padding: 0 var(--space-xl);
  }
  
  /* Hide burger menu on desktop */
  .burger-menu {
    display: none;
  }
  
  /* Show navigation horizontally */
  .main-nav {
    position: static;
    max-height: none;
    overflow: visible;
    border-bottom: none;
    background-color: transparent;
  }
  
  .main-nav ul {
    flex-direction: row;
    gap: var(--space-lg);
  }
  
  .main-nav li {
    border-bottom: none;
  }
  
  .main-nav a {
    padding: var(--space-sm) var(--space-md);
    min-height: auto;
    position: relative;
  }
  
  .main-nav a:hover {
    background-color: transparent;
    color: var(--color-warm-grey-dark);
  }
  
  /* Active page indicator - underline style for desktop */
  .main-nav a.active {
    background-color: transparent;
    font-weight: var(--font-weight-medium);
  }
  
  .main-nav a.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: var(--space-md);
    right: var(--space-md);
    height: 2px;
    background-color: var(--color-black);
  }
}

/* Wide screens (1920px and up) */
@media (width >= 1920px) {
  .header-container {
    padding: 0 var(--space-2xl);
  }
  
  .brand h1 {
    font-size: var(--font-size-3xl);
  }
  
  .main-nav ul {
    gap: var(--space-xl);
  }
}