/* BorderGlow — cursor-following gradient border + edge glow. */

[data-border-glow] {
  --edge-proximity: 0;
  --cursor-angle: 45deg;
  --edge-sensitivity: 30;
  --color-sensitivity: calc(var(--edge-sensitivity) + 20);
  --glow-padding: 34px;
  --cone-spread: 25;
  --fill-opacity: .45;
  --card-bg: #fff;

  /* Brand gold, saturated enough to read against a light page. */
  --glow-color: hsl(45deg 90% 52% / 100%);
  --glow-color-60: hsl(45deg 90% 52% / 60%);
  --glow-color-50: hsl(45deg 90% 52% / 50%);
  --glow-color-40: hsl(45deg 90% 52% / 40%);
  --glow-color-30: hsl(45deg 90% 52% / 30%);
  --glow-color-20: hsl(45deg 90% 52% / 20%);
  --glow-color-10: hsl(45deg 90% 52% / 10%);

  --gradient-one:   radial-gradient(at 80% 55%, #2563EB 0px, transparent 50%);
  --gradient-two:   radial-gradient(at 69% 34%, #F5C518 0px, transparent 50%);
  --gradient-three: radial-gradient(at 8%  6%,  #3B82F6 0px, transparent 50%);
  --gradient-four:  radial-gradient(at 41% 38%, #2563EB 0px, transparent 50%);
  --gradient-five:  radial-gradient(at 86% 85%, #F5C518 0px, transparent 50%);
  --gradient-six:   radial-gradient(at 82% 18%, #3B82F6 0px, transparent 50%);
  --gradient-seven: radial-gradient(at 51% 4%,  #F5C518 0px, transparent 50%);
  --gradient-base:  linear-gradient(#2563EB 0 100%);

  position: relative;
  isolation: isolate;              /* keeps the z-index:-1 layers inside the card */
  overflow: visible;               /* the outer glow extends past the card */
  transform: translate3d(0, 0, 0.01px);
}

[data-border-glow]::before,
[data-border-glow]::after,
[data-border-glow] > .edge-light {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  transition: opacity .25s ease-out;
  z-index: -1;
  pointer-events: none;
}

[data-border-glow]:not(:hover)::before,
[data-border-glow]:not(:hover)::after,
[data-border-glow]:not(:hover) > .edge-light {
  opacity: 0;
  transition: opacity .75s ease-in-out;
}

[data-border-glow]::before {
  border: 1px solid transparent;
  background:
    linear-gradient(var(--card-bg) 0 100%) padding-box,
    linear-gradient(rgb(255 255 255 / 0%) 0% 100%) border-box,
    var(--gradient-one) border-box,
    var(--gradient-two) border-box,
    var(--gradient-three) border-box,
    var(--gradient-four) border-box,
    var(--gradient-five) border-box,
    var(--gradient-six) border-box,
    var(--gradient-seven) border-box,
    var(--gradient-base) border-box;

  opacity: calc((var(--edge-proximity) - var(--color-sensitivity)) / (100 - var(--color-sensitivity)));

  mask-image:
    conic-gradient(
      from var(--cursor-angle) at center,
      black calc(var(--cone-spread) * 1%),
      transparent calc((var(--cone-spread) + 15) * 1%),
      transparent calc((100 - var(--cone-spread) - 15) * 1%),
      black calc((100 - var(--cone-spread)) * 1%)
    );
}

[data-border-glow]::after {
  border: 1px solid transparent;
  background:
    var(--gradient-one) padding-box,
    var(--gradient-two) padding-box,
    var(--gradient-three) padding-box,
    var(--gradient-four) padding-box,
    var(--gradient-five) padding-box,
    var(--gradient-six) padding-box,
    var(--gradient-seven) padding-box,
    var(--gradient-base) padding-box;

  mask-image:
    linear-gradient(to bottom, black, black),
    radial-gradient(ellipse at 50% 50%, black 40%, transparent 65%),
    radial-gradient(ellipse at 66% 66%, black 5%, transparent 40%),
    radial-gradient(ellipse at 33% 33%, black 5%, transparent 40%),
    radial-gradient(ellipse at 66% 33%, black 5%, transparent 40%),
    radial-gradient(ellipse at 33% 66%, black 5%, transparent 40%),
    conic-gradient(from var(--cursor-angle) at center, transparent 5%, black 15%, black 85%, transparent 95%);
  -webkit-mask-composite: source-out, source-over, source-over, source-over, source-over, source-over;
  mask-composite: subtract, add, add, add, add, add;

  opacity: calc(var(--fill-opacity) * (var(--edge-proximity) - var(--color-sensitivity)) / (100 - var(--color-sensitivity)));
  mix-blend-mode: soft-light;
}

/* Outer glow halo. */
[data-border-glow] > .edge-light {
  inset: calc(var(--glow-padding) * -1);
  z-index: -1;
  mask-image:
    conic-gradient(from var(--cursor-angle) at center, black 2.5%, transparent 10%, transparent 90%, black 97.5%);
  opacity: calc((var(--edge-proximity) - var(--edge-sensitivity)) / (100 - var(--edge-sensitivity)));

  mix-blend-mode: normal;
}

[data-border-glow] > .edge-light::before {
  content: "";
  position: absolute;
  inset: var(--glow-padding);
  border-radius: inherit;
  box-shadow:
    inset 0 0 0 1px var(--glow-color),
    inset 0 0 1px 0 var(--glow-color-60),
    inset 0 0 3px 0 var(--glow-color-50),
    inset 0 0 6px 0 var(--glow-color-40),
    inset 0 0 15px 0 var(--glow-color-30),
    inset 0 0 25px 2px var(--glow-color-20),
    inset 0 0 50px 2px var(--glow-color-10),
    0 0 1px 0 var(--glow-color-60),
    0 0 3px 0 var(--glow-color-50),
    0 0 6px 0 var(--glow-color-40),
    0 0 15px 0 var(--glow-color-30),
    0 0 25px 2px var(--glow-color-20),
    0 0 50px 2px var(--glow-color-10);
}

.vh-feature[data-border-glow] { --card-bg: #fff; }
.vh-quote[data-border-glow]   { --card-bg: #fff; }

.vh-principle[data-border-glow] { --card-bg: #0C1826; }

@media (prefers-reduced-motion: reduce) {
  [data-border-glow]::before,
  [data-border-glow]::after,
  [data-border-glow] > .edge-light { display: none; }
}