/* Approved B: a slow 3.2-second glow; editable, accessible HTML lettering. */
.sd .sd-hero .sd-button[href="#sd-check"],
.shindan-page .sd .sd-check .sd-button {
  position: relative;
  isolation: isolate;
  overflow: visible;
  border-color: transparent;
  border-radius: 12px;
  background: linear-gradient(#1e7551, #0c5037);
  box-shadow: none;
  font-size: 22px;
  line-height: 1.6;
}
.sd .sd-hero .sd-button[href="#sd-check"]::before,
.sd .sd-check .sd-button::before {
  content: "";
  position: absolute;
  z-index: -1;
  pointer-events: none;
  /* The approved image has a 512 x 80 face inside a 560 x 136 canvas. */
  inset: -31.25% -4.6875% -38.75%;
  background: url("/shindan/assets/button-glow-b-v1.gif?v=3") center / 100% 100% no-repeat;
}
.sd .sd-hero .sd-button[href="#sd-check"]:focus-visible,
.sd .sd-check .sd-button:focus-visible {
  outline: 3px solid #865900;
  outline-offset: 5px;
}
.sd .sd-check .sd-button:disabled::before {
  display: none;
}
.sd .sd-check .sd-button:disabled {
  cursor: progress;
  transform: none;
}
/* Keep explanatory text above the decorative glow's outer canvas. */
.sd .sd-hero-note,
.sd .sd-submit + .sd-small {
  position: relative;
  z-index: 0;
}
@media (max-width: 760px) {
  .sd .sd-hero .sd-button[href="#sd-check"],
  .shindan-page .sd .sd-check .sd-button {
    font-size: 20px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .sd .sd-hero .sd-button[href="#sd-check"]::before,
  .sd .sd-check .sd-button::before {
    background-image: url("/shindan/assets/button-glow-b-v1-still.png");
  }
  .sd .sd-hero .sd-button[href="#sd-check"],
  .sd .sd-check .sd-button {
    transition: none;
    transform: none;
  }
}

/* B glow remains visible around the button, independent of GIF compositing. */
@keyframes sd-button-glow-b {
  0%, 100% { box-shadow:0 0 0 2px #9ed26a,0 0 8px 3px rgba(151,204,57,.30); }
  50% { box-shadow:0 0 0 3px #c5ed6c,0 0 18px 8px rgba(145,206,37,.70),0 0 30px 12px rgba(185,226,63,.28); }
}
@media (prefers-reduced-motion: no-preference) {
  .sd .sd-hero .sd-button[href="#sd-check"],
  .shindan-page .sd .sd-check .sd-button:not(:disabled) {
    animation:sd-button-glow-b 3.2s ease-in-out infinite;
  }
}
.shindan-page .sd .sd-check .sd-button:disabled { animation:none; box-shadow:none; }