.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

:root {
  --sky: #d6f6ff;
  --ink: #164e5b;
}

* {
  box-sizing: border-box;
}

html,
body {
  min-height: 100%;
  margin: 0;
  overflow: hidden;
  background: var(--sky);
}

body {
  font-family: ui-rounded, 'Avenir Next', Avenir, 'Trebuchet MS', sans-serif;
  color: var(--ink);
}

.postcard-page {
  position: relative;
  isolation: isolate;
  min-height: 100svh;
  overflow: hidden;
  background: var(--sky);
}

.postcard-stage {
  position: absolute;
  inset: 0;
  z-index: 1;
  display: grid;
  place-items: center;
}

.postcard-scene {
  position: relative;
  z-index: 1;
  width: min(100vw, calc(100svh * 1.4072));
  height: min(100svh, calc(100vw / 1.4072));
  aspect-ratio: 419.25 / 297.75;
  -webkit-mask-image: linear-gradient(
    to right,
    transparent 0,
    #000 2%,
    #000 98%,
    transparent 100%
  );
  mask-image: linear-gradient(
    to right,
    transparent 0,
    #000 2%,
    #000 98%,
    transparent 100%
  );
}

.ocean-extension {
  position: absolute;
  top: 50%;
  left: 50%;
  z-index: 0;
  width: 100vw;
  height: min(100svh, calc(100vw / 1.4072));
  overflow: visible;
  transform: translate(-50%, -50%);
  pointer-events: none;
}

.ocean-extension::before,
.ocean-extension::after {
  content: '';
  position: absolute;
}

.ocean-extension::before {
  top: 82%;
  bottom: 0;
  right: -3rem;
  left: -3rem;
  background-color: #70d1db;
  background-image: url('./water-texture.png');
  background-repeat: no-repeat;
  background-position: center;
  background-size: 100% 100%;
  animation: ocean-wide-drift 8s ease-in-out infinite alternate;
}

.ocean-extension::after {
  top: 99.5%;
  right: 0;
  left: 0;
  height: 100svh;
  background: #7bd6df;
}

.postcard-artwork {
  display: block;
  width: 100%;
  height: 100%;
  border: 0;
  object-fit: contain;
}

.paper-light {
  position: absolute;
  inset: 0;
  z-index: 2;
  background:
    linear-gradient(118deg, transparent 28%, rgb(255 255 255 / 14%) 48%, transparent 68%),
    radial-gradient(circle at 50% 108%, rgb(255 255 255 / 16%), transparent 36%);
  background-size: 210% 100%, 100% 100%;
  background-position: 180% 0, 0 0;
  mix-blend-mode: soft-light;
  pointer-events: none;
  animation: paper-shimmer 11s ease-in-out infinite;
}

.site-footer {
  position: fixed;
  z-index: 5;
  right: max(0.8rem, env(safe-area-inset-right));
  bottom: max(0.8rem, env(safe-area-inset-bottom));
}

.site-footer a {
  display: inline-flex;
  align-items: center;
  min-height: 2.5rem;
  padding: 0.55rem 1rem;
  border: 1px solid rgb(22 78 91 / 18%);
  border-radius: 999px;
  background: rgb(214 246 255 / 78%);
  box-shadow: 0 0.5rem 1.6rem rgb(15 89 102 / 13%);
  color: #164e5b;
  font-size: 0.875rem;
  font-weight: 650;
  letter-spacing: 0.02em;
  text-decoration: none;
  backdrop-filter: blur(0.75rem);
  transition:
    background-color 160ms ease,
    transform 160ms ease,
    box-shadow 160ms ease;
}

.site-footer a:hover {
  background: rgb(255 255 255 / 90%);
  box-shadow: 0 0.65rem 2rem rgb(15 89 102 / 18%);
  transform: translateY(-2px);
}

.site-footer a:focus-visible {
  outline: 3px solid #164e5b;
  outline-offset: 3px;
}

@keyframes paper-shimmer {
  0%, 25% { background-position: 180% 0, 0 0; }
  70%, 100% { background-position: -110% 0, 0 0; }
}

@keyframes ocean-wide-drift {
  from { transform: translateX(-0.8rem) scaleX(1.01); }
  to { transform: translateX(0.8rem) scaleX(1.025); }
}

@media (prefers-reduced-motion: reduce) {
  .paper-light,
  .ocean-extension::before {
    animation: none;
  }
}