Modern CSS Gradient Effects

<div class="d-flex flex-wrap align-items-center justify-content-center gap-3 p-3 h-100" style="min-height:200px">
  <button type="button" class="btn btn-primary btn-lg fx-shimmer-effect">Shop the sale</button>
  <div class="fx-shimmer-effect rounded-3">
    <img src="../assets/img/product-2.svg" alt="Shiny product" class="d-block object-fit-cover" style="width:110px;height:110px">
  </div>
</div>

/* CSS (already in assets/css/effects.css) */
.fx-shimmer-effect { position: relative; overflow: hidden; isolation: isolate; }
.fx-shimmer-effect::after {
  content: ""; position: absolute; top: 0; bottom: 0; left: 0; width: 60%; pointer-events: none;
  background: linear-gradient(110deg, transparent 20%, rgba(255, 255, 255, .55) 50%, transparent 80%);
  transform: translateX(-120%);
  animation: fx-shimmer-effect-sweep 3.2s ease-in-out infinite;
}
@keyframes fx-shimmer-effect-sweep { 0% { transform: translateX(-120%); } 45%, 100% { transform: translateX(260%); } }
@media (prefers-reduced-motion: reduce) {
  .fx-shimmer-effect, .fx-shimmer-effect::before, .fx-shimmer-effect::after, .fx-shimmer-effect *, .fx-shimmer-effect *::before, .fx-shimmer-effect *::after { animation: none !important; transition: none !important; }
}

<div class="d-flex flex-wrap align-items-center justify-content-center gap-3 p-3 h-100" style="min-height:200px">
  <img src="https://images.unsplash.com/photo-1758691462858-f1286e5daf40?auto=format&fit=crop&w=1200&h=800&q=70" alt="Photo with a colourful shadow" class="fx-gradient-shadow rounded-4 object-fit-cover" style="width:200px;height:135px">
</div>

/* CSS (already in assets/css/effects.css) */
.fx-gradient-shadow {
  box-shadow: -14px 12px 30px -10px rgba(var(--wt-primary-rgb), .55), 14px 12px 30px -10px rgba(var(--wt-secondary-rgb), .55), 0 22px 36px -14px rgba(var(--wt-accent-rgb), .55);
  transition: box-shadow .4s ease, transform .4s ease;
}
.fx-gradient-shadow:hover, .fx-gradient-shadow:focus-visible {
  transform: translateY(-4px);
  box-shadow: -20px 18px 40px -10px rgba(var(--wt-primary-rgb), .7), 20px 18px 40px -10px rgba(var(--wt-secondary-rgb), .7), 0 30px 46px -14px rgba(var(--wt-accent-rgb), .7);
}
@media (prefers-reduced-motion: reduce) {
  .fx-gradient-shadow, .fx-gradient-shadow::before, .fx-gradient-shadow::after, .fx-gradient-shadow *, .fx-gradient-shadow *::before, .fx-gradient-shadow *::after { animation: none !important; transition: none !important; }
}

<div class="d-flex flex-wrap align-items-center justify-content-center gap-3 p-3 h-100" style="min-height:200px">
  <div class="fx-iridescent rounded-4 p-4 shadow-sm" style="width:15rem">
    <div class="d-flex justify-content-between align-items-start mb-4">
      <span class="fw-bold">Bloom</span><i class="bi bi-gem" aria-hidden="true"></i>
    </div>
    <div class="font-monospace small mb-1">
      **** **** **** 6678
    </div>
    <div class="small">
      Diego Moreau
    </div>
  </div>
</div>

/* CSS (already in assets/css/effects.css) */
.fx-iridescent {
  position: relative; overflow: hidden; color: #1d1d2b;
  background: linear-gradient(120deg, #f6d5f7, #fbe9d7, #d5f2ef, #d7e2fb, #e9d5fb, #f6d5f7);
  background-size: 300% 300%; background-position: 0% 50%;
  transition: background-position 1.2s ease;
}
.fx-iridescent::after {
  content: ""; position: absolute; inset: 0; pointer-events: none; mix-blend-mode: overlay;
  background: linear-gradient(105deg, transparent 35%, rgba(255, 255, 255, .7) 50%, transparent 65%);
  background-size: 250% 100%; background-position: 100% 0; transition: background-position 1.2s ease;
}
.fx-iridescent:hover, .fx-iridescent:focus-within { background-position: 100% 50%; }
.fx-iridescent:hover::after, .fx-iridescent:focus-within::after { background-position: 0 0; }
@media (prefers-reduced-motion: reduce) {
  .fx-iridescent, .fx-iridescent::before, .fx-iridescent::after, .fx-iridescent *, .fx-iridescent *::before, .fx-iridescent *::after { animation: none !important; transition: none !important; }
}