.smrpwa-install-btn {
    display: none;
    position: fixed;
    z-index: 999999;
    background: #ff0000;
    color: #ffffff;
    border: none;
    padding: 12px 18px;
    border-radius: 30px;
    font-weight: 600;
    cursor: pointer;
    box-shadow: 0 6px 14px rgba(0,0,0,0.18);
}

/* position helpers */
.smrpwa-install-btn--top { top: 20px; }
.smrpwa-install-btn--bottom { bottom: 20px; }
.smrpwa-install-btn--left { left: 20px; transform: none; }
.smrpwa-install-btn--right { right: 20px; transform: none; }
.smrpwa-install-btn--center-h { left: 50%; transform: translateX(-50%); }
.smrpwa-install-btn--center-v { top: 50%; transform: translateY(-50%); }

@media (max-width:600px){
    .smrpwa-install-btn { padding:10px 14px; font-size:14px; }
}