#back-to-top-btn {
    position: fixed;
    right: 1rem;
    bottom: 1rem;
    z-index: 1040;
    background: rgb(25, 22, 37);
    border: 4px solid rgb(219, 192, 255);
    width: 50px;
    height: 50px;
    border-radius: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: opacity 0.3s, visibility 0.3s, transform 0.3s, box-shadow 0.3s, background 0.3s, border-color 0.3s;
    box-shadow: 4px 4px 0px rgba(0, 0, 0, 0.5);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateY(10px);
}

#back-to-top-btn.is-visible {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateY(0);
}

#back-to-top-btn:hover {
    transform: translate(2px, 2px);
    box-shadow: 2px 2px 0px rgba(0, 0, 0, 0.5);
}

#back-to-top-btn svg {
    width: 28px;
    height: 28px;
    fill: rgb(219, 192, 255);
}

[data-bs-theme="light"] #back-to-top-btn {
    background: rgb(230, 226, 211);
    border-color: rgb(44, 44, 44);
}

[data-bs-theme="light"] #back-to-top-btn svg {
    fill: rgb(44, 44, 44);
}