.fab-button,
.fab-button.secondary {
    position: fixed;
    right: 24px;
    bottom: 24px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    border: none;
    border-radius: 50%;
    background: #1f2937;
    color: #ffffff;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.16);
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease, opacity 0.2s ease;
    opacity: 0;
    visibility: hidden;
    z-index: 999;
}

.fab-button.is-visible {
    opacity: 1;
    visibility: visible;
}

.fab-button:hover,
.fab-button:focus {
    transform: translateY(-2px);
    box-shadow: 0 14px 24px rgba(0, 0, 0, 0.2);
}

.fab-button:active {
    transform: translateY(0);
}

.fab-button svg {
    width: 20px;
    height: 20px;
}

.fab-button.secondary {
    background: #1f2937;
}

.fab-button.secondary + .fab-button {
    bottom: 88px;
}