/**
 * Tech Sutro — Header & Navigation Styles
 * Bold Tech / Dark Glass — fixed frosted-glass header, pill nav links,
 * glass theme toggle and a full-screen frosted mobile menu.
 */

/* ==================================================================
   HEADER BASE
   ================================================================== */

.site-header {
  position: fixed;
  inset-inline: 0;
  top: 0;
  z-index: var(--z-header);

  background: transparent;
  border-bottom: 1px solid transparent;

  transition:
    background-color var(--transition-base),
    border-color var(--transition-base),
    box-shadow var(--transition-base);
}

/*
 * Soft scrim at the top of the page so the logo / nav stay legible
 * when the header is transparent over the hero media. Fades out as
 * soon as the frosted scrolled state takes over.
 */
/* .site-header::before {
  content: '';
  position: absolute;
  inset: 0;
  z-index: -1;

  background: linear-gradient(
    180deg,
    var(--header-scrim) 0%,
    transparent 78%
  );

  opacity: 1;
  pointer-events: none;

  transition: opacity var(--transition-base);
} */

.site-header.is-scrolled::before {
  opacity: 0;
}

/* Frosted glass on scroll. */
.site-header.is-scrolled {
  background: var(--glass-bg-strong);

  border-bottom-color: var(--border-subtle);

  backdrop-filter: blur(var(--glass-blur)) saturate(140%);
  -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(140%);

  box-shadow:
    var(--shadow-md),
    inset 0 1px 0 0 var(--glass-highlight);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;

  min-height: 72px;
  gap: var(--space-4);
}

/* ==================================================================
   LOGO
   ================================================================== */

.header-logo {
  display: flex;
  align-items: center;
  gap: 0.65rem;

  text-decoration: none;
  color: var(--text-primary);

  flex-shrink: 0;

  transition: opacity var(--transition-fast);
}

.header-logo:hover {
  opacity: 0.86;
}

.logo-img {
  height: 60px;
  width: auto;
  display: block;

  border-radius: var(--radius-sm);
}

.logo-fallback {
  display: inline-flex;
  align-items: center;
  justify-content: center;

  height: 38px;
  padding-inline: 0.85rem;

  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);

  background: var(--glass-bg-soft);

  backdrop-filter: blur(12px) saturate(140%);
  -webkit-backdrop-filter: blur(12px) saturate(140%);
}

.logo-text {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.05rem;
  letter-spacing: -0.02em;

  background: var(--accent-gradient);
  -webkit-background-clip: text;
          background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
}

/* ==================================================================
   DESKTOP NAVIGATION
   ================================================================== */

.site-nav {
  display: none;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 0.25rem;

  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-item {
  display: flex;
}

.nav-link {
  display: inline-flex;
  align-items: center;

  padding: 0.55rem 1rem;

  border-radius: var(--radius-full);

  font-size: var(--text-sm);
  font-weight: 500;
  letter-spacing: 0.01em;

  color: var(--text-secondary);
  text-decoration: none;

  position: relative;

  transition:
    color var(--transition-fast),
    background-color var(--transition-fast),
    box-shadow var(--transition-fast);
}

/* Glass tint pill on hover. */
.nav-link:hover {
  color: var(--text-primary);
  background: var(--glass-bg-soft);

  backdrop-filter: blur(10px) saturate(140%);
  -webkit-backdrop-filter: blur(10px) saturate(140%);
}

/* Active: accent text on a soft gradient wash. */
.nav-link.is-active {
  color: var(--accent-primary);
  font-weight: 600;

  background: var(--accent-gradient-soft);
}

/* Gradient hairline underline under the active link. */
.nav-link.is-active::after {
  content: '';

  position: absolute;
  bottom: 2px;
  left: 50%;

  transform: translateX(-50%);

  width: 18px;
  height: 2.5px;

  border-radius: var(--radius-full);

  background: var(--accent-gradient);
  box-shadow: 0 0 12px var(--accent-glow);
}

.nav-link:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 3px;
}

@media (min-width: 992px) {
  .site-nav {
    display: block;
  }
}

/* ==================================================================
   HEADER ACTIONS
   Theme toggle + mobile trigger
   ================================================================== */

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;

  flex-shrink: 0;
}

/* ==================================================================
   THEME TOGGLE
   Glass square with accent glow on hover.
   ================================================================== */

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;

  width: 42px;
  height: 42px;

  padding: 0;

  border-radius: var(--radius-md);
  border: 1px solid var(--glass-border);

  background: var(--glass-bg-soft);
  color: var(--text-primary);

  cursor: pointer;

  backdrop-filter: blur(12px) saturate(140%);
  -webkit-backdrop-filter: blur(12px) saturate(140%);

  transition:
    transform var(--transition-fast),
    background-color var(--transition-fast),
    border-color var(--transition-fast),
    color var(--transition-fast),
    box-shadow var(--transition-fast);
}

/* Icon sizing */
.theme-toggle svg {
  width: 18px;
  height: 18px;
  flex-shrink: 0;

  transition: transform var(--transition-base);
}

/* Subtle rotate / scale of the icon on hover. */
.theme-toggle:hover .icon-sun,
.theme-toggle:hover .icon-moon {
  transform: rotate(14deg) scale(1.08);
}

/* Hover — accent border + soft glow. */
.theme-toggle:hover {
  background: var(--glass-bg);
  border-color: color-mix(in oklab, var(--accent-primary), transparent 50%);
  color: var(--accent-primary);

  transform: translateY(-1px);

  box-shadow: 0 10px 24px -10px var(--accent-glow);
}

.theme-toggle:active {
  transform: translateY(0) scale(0.96);
}

/* Focus accessibility */
.theme-toggle:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 3px;
}

/* ==================================================================
   THEME TOGGLE ICON VISIBILITY
   ================================================================== */

/* Hide both icons by default */
.theme-toggle .icon-sun,
.theme-toggle .icon-moon {
  display: none;
}

/* Dark mode → moon */
html[data-theme='dark'] .theme-toggle .icon-moon {
  display: block;
}

/* Light mode → sun */
html[data-theme='light'] .theme-toggle .icon-sun {
  display: block;
}

/* Fallback before JavaScript initializes → sun */
html:not([data-theme]) .theme-toggle .icon-sun {
  display: block;
}

/* ==================================================================
   MOBILE MENU TOGGLE
   Hamburger → X animation.
   ================================================================== */

.mobile-menu-toggle {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;

  gap: 5px;

  width: 42px;
  height: 42px;

  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);

  background: var(--glass-bg-soft);
  color: var(--text-primary);

  cursor: pointer;
  padding: 0;

  backdrop-filter: blur(12px) saturate(140%);
  -webkit-backdrop-filter: blur(12px) saturate(140%);

  transition:
    background-color var(--transition-fast),
    border-color var(--transition-fast),
    box-shadow var(--transition-fast);
}

.mobile-menu-toggle:hover {
  border-color: color-mix(in oklab, var(--accent-primary), transparent 50%);
  box-shadow: 0 10px 24px -10px var(--accent-glow);
}

.mobile-menu-toggle:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 3px;
}

.mobile-menu-toggle .bar {
  display: block;

  width: 20px;
  height: 2px;

  background: currentColor;

  border-radius: var(--radius-full);

  transition:
    transform var(--transition-base),
    opacity var(--transition-base),
    background-color var(--transition-fast);
}

.mobile-menu-toggle.is-open {
  color: var(--accent-primary);
  border-color: color-mix(in oklab, var(--accent-primary), transparent 50%);
}

.mobile-menu-toggle.is-open .bar {
  background: var(--accent-gradient);
}

.mobile-menu-toggle.is-open .bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.mobile-menu-toggle.is-open .bar:nth-child(2) {
  opacity: 0;
}

.mobile-menu-toggle.is-open .bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

@media (min-width: 992px) {
  .mobile-menu-toggle {
    display: none;
  }
}

/* ==================================================================
   MOBILE MENU PANEL
   Full-screen frosted glass slide-in.
   ================================================================== */

.mobile-menu {
  position: fixed;

  inset: 0;
  top: 0;

  z-index: calc(var(--z-header) + 10);

  background: color-mix(
    in oklab,
    var(--glass-bg-strong),
    var(--bg-page) 30%
  );

  backdrop-filter: blur(28px) saturate(150%);
  -webkit-backdrop-filter: blur(28px) saturate(150%);

  display: flex;
  flex-direction: column;

  padding: 88px var(--space-6) var(--space-8);

  transform: translateX(100%);

  transition: transform var(--transition-slow);

  overflow-y: auto;
}

/* Gradient hairline along the top edge of the panel. */
.mobile-menu::before {
  content: '';

  position: absolute;
  top: 0;
  left: 0;
  right: 0;

  height: 2px;

  background: var(--accent-gradient);

  opacity: 0.7;
  pointer-events: none;
}

.mobile-menu.is-open {
  transform: translateX(0);
}

.mobile-nav-list {
  list-style: none;

  display: flex;
  flex-direction: column;

  gap: 0.35rem;

  margin: 0;
  padding: 0;
}

.mobile-nav-link {
  display: flex;
  align-items: center;

  padding: 0.85rem 1rem;

  border-radius: var(--radius-lg);

  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 600;

  color: var(--text-secondary);

  text-decoration: none;

  position: relative;

  transition:
    color var(--transition-fast),
    background-color var(--transition-fast),
    box-shadow var(--transition-fast);
}

.mobile-nav-link:hover {
  color: var(--text-primary);
  background: var(--glass-bg-soft);
}

/* Active: accent text, gradient wash, accent glow. */
.mobile-nav-link.is-active {
  color: var(--accent-primary);

  background: var(--accent-gradient-soft);

  box-shadow: inset 0 0 0 1px
    color-mix(in oklab, var(--accent-primary), transparent 82%);
}

.mobile-menu-footer {
  margin-top: auto;

  padding-top: var(--space-8);

  border-top: 1px solid var(--border-subtle);
}

.mobile-menu-parent {
  font-size: var(--text-sm);
  color: var(--text-muted);
}