/* ====================================================
   IMÁN INFERIOR EN LAS PÁGINAS INTERIORES (2026-10-20)
   Sustituye al botón .back-to-top. Misma posición que en la portada:
   centro en (ancho/2 + 450) y línea de contacto a 91 px del borde inferior.
   ==================================================== */
:root { --im-k: 0.6667; } /* 2/3 del tamaño de la portada */
@media (max-width: 759px) { :root { --im-k: 0.3667; } }
.im-low {
  position: fixed;
  left: var(--im-x, calc(100% - 72px));
  top: calc(var(--im-contact, calc(100vh - 91px)) - 18.75px * var(--im-k, 1));
  transform: translateX(-50%);
  width: calc(112.5px * var(--im-k, 1));
  height: calc(112.5px * var(--im-k, 1));
  z-index: 20;
  cursor: pointer;
  background: transparent;
  border: none;
  padding: 0;
  margin: 0;
  overflow: visible;
  display: none;
  outline: none;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}
html.im-on .im-low { display: block; }
html.im-on .back-to-top { display: none !important; }
.im-low:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.im-low-bounce { display: block; position: relative; width: calc(112.5px * var(--im-k, 1)); height: calc(112.5px * var(--im-k, 1)); transform-origin: center top; }
.im-low-window { display: block; position: relative; width: calc(112.5px * var(--im-k, 1)); height: calc(112.5px * var(--im-k, 1)); overflow: hidden; border-radius: 2px; transition: transform 120ms ease-out; }
.im-low:active .im-low-window { transform: scale(0.97); }
.im-strip { display: block; height: calc(112.5px * var(--im-k, 1)); width: calc(112.5px * var(--im-k, 1) * 37); max-width: none; transform: translate3d(0, 0, 0); will-change: transform; }
.im-low.im-clac .im-low-bounce { animation: imLowBote .4s cubic-bezier(.3,1.6,.5,1); }
@keyframes imLowBote { 0% { transform: translateY(-6px); } 60% { transform: translateY(2px); } 100% { transform: none; } }
@media (prefers-reduced-motion: reduce) { .im-low.im-clac .im-low-bounce { animation: none; } }