Font awesome sun icon not showing

<div class="search-wrapper">
          <form action="" class="search-form">
          </form>

          <button class="dark-light-mode">
            <i class="fa-sharp fa-regular fa-sun-bright"></i>
          </button>
        </div>

.dark-light-mode{
    outline: 2px solid red;
    display: flex;
    align-items: center ;
    justify-content: center;
}