.dx-texteditor-input-container.input-alert:before {
    content: '';
    border-radius: 20px;
    width: 10px;
    height: 10px;
    top: 50%;
    transform: translateY(-50%);
    right: 10px;
    position: absolute;
    display: block;
}
    .dx-texteditor-input-container.input-alert.alert-red:before {
        background-color: rgba(217,83,79,.4);
    }
    .dx-texteditor-input-container.input-alert.alert-yellow:before {
        background-color: rgba(216, 151, 32, 1);
    }
    .dx-texteditor-input-container.input-alert.alert-green:before {
        background-color: rgba(67,184,53,1);
    }

    .dx-texteditor-input-container.input-alert input {
        width: 90%;
    }