You just have to click the below light / dark button:

There’s a color box at bottom right of the builder. Just change it to your desired color scheme:

This is because you’re in page editing mode. You just need to click the below & you can now edit the blocks again:

By default, your latest work will be saved on your browser cache. Thus, when you re-open our builder the next day on the same browser, it will automatically load your latest work. But you may also choose to save it for backup purposes & load it later on.

To save your current work, just click the below & it will download a file with extension .diviblock:

And to load your saved work, just click the below & upload the .diviblock file:

Check this out: https://diviblock.com/how-to-import-json-file/

If you’re unable to import the json file, check if you have Wordfence plugin installed on your Divi site. If yes, then try to disable it & import the json again.

Step 1: Add the below CSS in Divi > Theme Options > Custom CSS:

.et-fb-settings-option-inner-upload--previewable .et-fb-settings-option-input.et-fb-settings-option-upload {
    display: block!important;
    width: 100%!important;
    margin-top: 42px;
}
.et-fb-settings-option-inner-upload--previewable:after {
    margin: 0 0 4px;
    color: #32373c;
    font-size: .875rem;
    font-weight: 600;
    content: 'Image URL';
    position: absolute;
    bottom: 33px;
}

Step 2: Look for your image in the module settings & you will see a new option called Image URL (see screenshot below):

From the image URL, the last 2 values as shown above is the width & height. Take the screenshot for example, the width of the image is 1000px & height is 500px.