/* V5: mismo marco plano V4, con sombra interior sobre la lámina. */
.psv3-gallery-host { position: relative !important; }
.psv3-flat-border {
  position: absolute !important;
  box-sizing: border-box !important;
  display: block;
  border: var(--psv3-border-width, 9px) solid var(--psv3-frame-color, #222) !important;
  border-radius: 0 !important;
  outline: 0 !important;
  box-shadow: 2px 3px 4px rgba(0,0,0,0.17), 3px 5px 9px rgba(0,0,0,0.23) !important;
  filter: none !important;
  background: transparent !important;
  opacity: 1 !important;
  padding: 0 !important;
  margin: 0 !important;
  pointer-events: none !important;
  z-index: 20 !important;
}
.psv3-flat-border[hidden] { display: none !important; }
.psv3-flat-border.psv3-white { outline: 1px solid rgba(0,0,0,0.13) !important; outline-offset: -1px !important; }

/* Nueva V5: sombreado interior real justo detrás del borde.
   El pseudo-elemento cae dentro del marco, sin alterar la lámina ni el grosor.
   Solo sombrea los primeros píxeles del interior, como en un cuadro con vidrio. */
.psv3-flat-border::after {
  content: "";
  position: absolute;
  inset: 0;
  display: block;
  pointer-events: none;
  background: transparent;
  border: 0;
  border-radius: 0;
  box-shadow:
    inset 2px 2px 5px rgba(0, 0, 0, 0.23),
    inset -3px -3px 6px rgba(0, 0, 0, 0.18);
}