.whatsapp {
    position: fixed;
    bottom: 30px;
    right: 25px;

    width: 60px;
    height: 60px;

    background-color: #25D366;
    border-radius: 50%;

    display: flex;
    align-items: center;
    justify-content: center;

    cursor: pointer;
    z-index: 1000;

    box-shadow: 0 4px 10px rgba(0,0,0,0.3);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

/* hover (desktop) */
.whatsapp:hover{
    transform: scale(1.1);
    box-shadow: 0 6px 15px rgba(0,0,0,0.4);
}

/* ícone */
.whatsapp svg{
    width: 35px;
    height: 35px;
}

/* MOBILE */
@media (max-width: 768px) {
    .whatsapp {
        bottom: 20px;   /* mais espaço da borda */
        right: 15px;

        width: 55px;    /* levemente menor */
        height: 55px;
    }

    .whatsapp svg {
        width: 30px;
        height: 30px;
    }
}

/* TELAS MUITO PEQUENAS */
@media (max-width: 400px) {
    .whatsapp {
        bottom: 15px;
        right: 10px;

        width: 50px;
        height: 50px;
    }

    .whatsapp svg {
        width: 26px;
        height: 26px;
    }
}