解决CSS Hover效果在独立SVG中有效，但在Card组件中失效的问题

.center__div--heartFilled {
  /* z-index: -1;  Remove this line */
}

<div class="card restaurant__card">
  <a href="#">
    <div class="card__image">
      <img src="https://zupimages.net/up/21/31/oomv.jpg">
    </div>
    <div class="card__body">

      <div class="card__title">
        <h3>À la française</h3>
        <p>Cité Rouge</p>
      </div>

      <div class="card__heart">
        <div class="center__div center__div--heartFilled">
          <svg class="svg__heart--filled" width="29" height="29" viewBox="0 0 16 16">
            <defs>
              <linearGradient id="grad1" x1="0%" y1="100%" x2="50%" y2="0%">
                <stop offset="0%" class="color-primary" />
                <stop offset="100%" class="color-secondary" />
              </linearGradient>
            </defs>
            <path d="M8 1.314C12.438-3.248 23.534 4.735 8 15-7.534 4.736 3.562-3.248 8 1.314z" fill="url(#grad1)"></path>
          </svg>
        </div>

        <div class="center__div">
          <svg class="svg__heart--outline" width="30" height="30" fill="currentColor" viewBox="0 0 16 16">
            <path d="m8 2.748-.717-.737C5.6.281 2.514.878 1.4 3.053c-.523 1.023-.641 2.5.314 4.385.92 1.815 2.834 3.989 6.286 6.357 3.452-2.368 5.365-4.542 6.286-6.357.955-1.886.838-3.362.314-4.385C13.486.878 10.4.28 8.717 2.01L8 2.748zM8 15C-7.333 4.868 3.279-3.04 7.824 1.143c.06.055.119.112.176.171a3.12 3.12 0 0 1 .176-.17C12.72-3.042 23.333 4.867 8 15z" />
          </svg>
        </div>
      </div>
    </div>
  </a>
</div>

body {
  background: black;
}

body a {
  text-decoration: none;
  color: black;
}

.card {
  width: 90%;
  height: 225px;
  margin-bottom: 25px;
  border-radius: 15px;
  overflow: hidden;
}

.card__image {
  height: 160px;
}

.card__image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.card__body {
  height: 65px;
  width: 100%;
  display: flex;
  align-items: center;
  flex-flow: row wrap;
  justify-content: space-between;
  background: white;
}

.card__title {
  padding-left: 15px;
  display: flex;
  flex-flow: column wrap;
  gap: 3px;
}

.card__title h3 {
  margin-top: 0px;
  margin-bottom: 0px;
}

.card__title p {
  margin-top: 0px;
  margin-bottom: 0px;
}

.card__heart {
  margin-right: 40px;
  border: solid black 1px;
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
  width: 32px;
  height: 32px;
}


/* styliser les svg heart */

.center__div {
  width: 32px;
  height: 32px;
  position: absolute;
  cursor: pointer;
}

.center__div--heartFilled {
  /* z-index: -1;  Remove this line */
}

.svg__heart--filled {
  opacity: 0;
  transition: all 500ms ease-in-out;
}

.card__heart:hover .svg__heart--filled {
  opacity: 1;
}


/*.
.svg__heart--filled {
  opacity: 1;
}
*/

.svg__heart--outline {
  background: rgba(0, 0, 0, 0);
}

.color-primary {
  stop-color: yellow;
  stop-opacity: 1;
}

.color-secondary {
  stop-color: red;
  stop-opacity: 1;
}