/* Sticky header. Transparent over the hero, solid once scrolled. */

.nav {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  background: transparent;
  transition: background-color .3s var(--ease), box-shadow .3s var(--ease);
}
.nav.is-scrolled {
  background: rgba(255, 255, 255, .96);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-sm);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  width: 100%;
}

.nav__brand { display: flex; align-items: center; gap: 11px; text-decoration: none; }
.nav__logo {
  width: 40px;
  /* Artwork is solid black on transparency — invert it to white over the hero. */
  filter: brightness(0) invert(1);
  transition: filter .3s var(--ease);
}
.nav.is-scrolled .nav__logo { filter: none; }

.nav__wordmark {
  font-size: 19px;
  font-weight: 700;
  letter-spacing: .2px;
  color: var(--white);
  transition: color .3s var(--ease);
}
.nav.is-scrolled .nav__wordmark { color: var(--dark); }

.nav__links { display: flex; align-items: center; gap: 30px; }

.nav__link {
  position: relative;
  font-size: 15px;
  font-weight: 500;
  color: rgba(255, 255, 255, .85);
  text-decoration: none;
  transition: color .2s var(--ease);
}
.nav__link::after {
  content: "";
  position: absolute;
  left: 0; bottom: -5px;
  width: 100%; height: 2px;
  background: currentColor;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform .25s var(--ease);
}
.nav__link:hover::after { transform: scaleX(1); }
.nav__link:hover { color: var(--white); }
.nav.is-scrolled .nav__link { color: var(--grey); }
.nav.is-scrolled .nav__link:hover { color: var(--teal); }

.nav__cta { padding: 11px 22px; font-size: 14px; }
.nav.is-scrolled .nav__cta { background: var(--teal); color: var(--white); border-color: transparent; }

.nav__toggle {
  display: none;
  width: 44px; height: 44px;
  padding: 0;
  border: 0;
  background: transparent;
  cursor: pointer;
}
.nav__toggle span {
  display: block;
  width: 22px; height: 2px;
  margin: 5px auto;
  border-radius: 2px;
  background: var(--white);
  transition: transform .3s var(--ease), opacity .2s var(--ease), background-color .3s var(--ease);
}
.nav.is-scrolled .nav__toggle span { background: var(--dark); }
.nav__toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav__toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav__toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }