.select2-container--open .select2-dropdown {
    position: relative !important;
    width: 100% !important;
    left: 0 !important;
    top: auto !important;
    z-index: 99999 !important;
    max-height: 300px;
    overflow-y: auto;
    background: #fff;
    border: 1px solid #ccc;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}