/* ==========================================================================
   Global sticky layer — logo (left), nav (center), mode switcher (right).
   Shared by all future sections/pages.
   ========================================================================== */

/* Fixed header bar; translucent active-mode canvas over hero image */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: var(--space-lg);
  padding: var(--space-lg) var(--space-huge);
  background-color: color-mix(in srgb, var(--c-canvas) 72%, transparent);
  backdrop-filter: blur(var(--space-md));
  -webkit-backdrop-filter: blur(var(--space-md));
  border-bottom: 1px solid var(--c-hairline);
}

/* Text wordmark — placeholder until /assets/logo/logo.jpg is provided */
.site-logo {
  justify-self: start;
  font-family: var(--font-display);
  font-size: 22px;      /* display-md */
  font-weight: 400;
  line-height: 1.25;
  letter-spacing: -0.3px;
  color: var(--c-text-primary);
  text-decoration: none;
}

/* Accent dot on wordmark */
.site-logo span {
  color: var(--c-accent-strong);
}

/* Primary navigation list */
.site-nav ul {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-xs) var(--space-xl);
  margin: 0;
  padding: 0;
  list-style: none;
}

/* Nav link — body-md, hover = text shift + accent underline */
.site-nav a {
  display: inline-block;
  padding: var(--space-sm) var(--space-xs);
  font-family: var(--font-body);
  font-size: 16px;      /* body-md */
  font-weight: 360;
  line-height: 1.5;
  color: var(--c-text-secondary);
  text-decoration: none;
  border-bottom: 2px solid transparent;
}

.site-nav a:hover,
.site-nav a:focus-visible {
  color: var(--c-text-primary);
  border-bottom-color: var(--c-accent);
}

/* Current page indicator */
.site-nav a[aria-current="page"] {
  color: var(--c-text-primary);
  border-bottom-color: var(--c-accent);
}

/* Day/Night switcher — 44px tap target, secondary-button styling */
.theme-toggle {
  justify-self: end;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  padding: 0;
  background: transparent;
  color: var(--c-text-primary);
  border: 1px solid var(--c-hairline-strong);
  border-radius: var(--rounded-sm);
  cursor: pointer;
}

.theme-toggle:hover,
.theme-toggle:focus-visible {
  border-color: var(--c-accent);
  color: var(--c-accent-strong);
}

.theme-toggle svg {
  width: 20px;
  height: 20px;
}

/* Show moon in Day Mode (switch to dark), sun in Dark Mode (switch to light) */
[data-theme="light"] .theme-toggle .icon-sun,
[data-theme="dark"] .theme-toggle .icon-moon {
  display: none;
}

/* Keyboard focus ring */
.site-nav a:focus-visible,
.theme-toggle:focus-visible,
.site-logo:focus-visible {
  outline: 2px solid var(--c-accent);
  outline-offset: var(--space-xxs);
}

/* Large tablet: tighten side padding */
@media (max-width: 1024px) {
  .site-header {
    padding: var(--space-lg) var(--space-xxl);
  }
}

/* Small tablet + mobile: nav drops to its own row, items wrap */
@media (max-width: 768px) {
  .site-header {
    grid-template-columns: 1fr auto;
    row-gap: var(--space-xs);
    padding: var(--space-md) var(--space-lg) var(--space-xs);
  }

  .site-nav {
    grid-column: 1 / -1;
    grid-row: 2;
  }

  .site-nav ul {
    gap: 0 var(--space-md);
  }
}

/* Mobile: smaller wordmark and nav text */
@media (max-width: 480px) {
  .site-logo {
    font-size: 18px;    /* display-sm */
    line-height: 1.3;
    letter-spacing: -0.2px;
  }

  .site-nav ul {
    justify-content: space-between;
    gap: 0 var(--space-sm);
  }

  .site-nav a {
    font-size: 14px;    /* body-sm */
    line-height: 1.45;
  }
}