html {
  scroll-behavior: smooth;
  scroll-padding-block-start: calc(var(--header-height) + var(--admin-bar-offset) + var(--space-s));
}

body {
  min-height: 100vh;
  background: var(--site-bg-outer);
  overflow-x: hidden;
}

.site-shell {
  position: relative;
  display: flex;
  flex-direction: column;
  min-height: 100dvh;
  width: min(100%, var(--site-max-width));
  margin-inline: auto;
  background: var(--site-bg-inner);
  box-shadow: var(--site-shell-shadow);
  overflow: clip;
}

.site-shell > main {
  flex: 1 0 auto;
}

.site-header-spacer {
  flex: 0 0 auto;
  block-size: var(--header-height);
}

.skip-link {
  position: fixed;
  inset-block-start: calc(var(--admin-bar-offset) + var(--space-xs));
  inset-inline-start: var(--space-s);
  z-index: 1000;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-block-size: 2.75rem;
  padding: 0.625rem 1rem;
  border-radius: var(--radius-pill);
  background: var(--color-heading);
  color: var(--color-neutral-0);
  text-decoration: none;
  box-shadow: var(--shadow-soft);
  transform: translateY(calc(-100% - var(--space-s)));
  transition: transform var(--transition-standard), background-color var(--transition-standard);
}

.skip-link:focus,
.skip-link:focus-visible {
  transform: translateY(0);
  background: var(--color-primary-700);
  color: var(--color-neutral-0);
}

body.admin-bar {
  --admin-bar-offset: 32px;
}

@media (max-width: 782px) {
  body.admin-bar {
    --admin-bar-offset: 46px;
  }
}

.scroll-top {
  position: fixed;
  inset-inline-end: max(1rem, calc((100vw - var(--site-max-width)) / 2 + 1rem));
  inset-block-end: 1rem;
  z-index: 120;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  inline-size: 3rem;
  block-size: 3rem;
  border: 1px solid var(--color-gold-soft);
  border-radius: 999px;
  background: var(--color-card-warm);
  color: var(--color-gold-deep);
  text-decoration: none;
  box-shadow: var(--shadow-soft);
  opacity: 0;
  pointer-events: none;
  transform: translateY(0.75rem);
  transition:
    opacity var(--duration-base) var(--easing-standard),
    transform var(--duration-base) var(--easing-standard),
    background-color var(--duration-base) var(--easing-standard),
    border-color var(--duration-base) var(--easing-standard),
    box-shadow var(--duration-base) var(--easing-standard),
    color var(--duration-base) var(--easing-standard);
}

.scroll-top__icon {
  display: inline-flex;
  inline-size: 1.7rem;
  block-size: 1.7rem;
  transform: rotate(-90deg);
  transition: transform var(--duration-base) var(--easing-standard);
}

.scroll-top__icon svg {
  inline-size: 100%;
  block-size: 100%;
}

/* The colour swap alone read as a flash; the border, lift, and arrow nudge
   give the transition something to carry. */
.scroll-top.is-visible:hover,
.scroll-top.is-visible:focus-visible {
  border-color: var(--color-gold);
  background: var(--color-gold-tint);
  color: var(--color-gold-deep);
  box-shadow: var(--shadow-large);
  transform: translateY(-0.2rem);
}

.scroll-top:hover .scroll-top__icon,
.scroll-top:focus-visible .scroll-top__icon { transform: rotate(-90deg) translateX(0.15rem); }

.scroll-top.is-visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .scroll-top,
  .scroll-top__icon {
    transition: none;
  }
}