.offcanvas-custom {
    position: fixed;
    top: 0;
    right: -520px;
    width: 500px;
    height: 100vh;
    background: #fff;
    z-index: 1060;
    transition: .25s;
    box-shadow: -5px 0 15px rgba(0,0,0,.2);
    display: flex;
    flex-direction: column;
}

    .offcanvas-custom.show {
        right: 0;
    }

.offcanvas-header {
    padding: 18px;
}

.offcanvas-body {
    flex: 1;
    overflow: auto;
    padding: 20px;
}

.offcanvas-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,.35);
    z-index: 1050;
}