No transition but a flash between two passages

Hello !

I’m currently writting my first story, I never learned how to code before and I’ve got a problem I don’t know how to solve. I’m using Twine 2 with Sugarcube 2.30.0.

The story isn’t a game, it is an interactive way to give advices to student. So there’s two parts : the first one is a discussion between two students, with speech bubbles. The students have to choose the answer they prefer, according to what they think is the better way. The second part is the advices. This is just a colored text area above the background image, but the background image is always visible around.

My text area in the 2nd part has always the same size, and I juste want the text to change when they go to the next passage (I don’t what the texte area to disappear). I found how to delete the fade-in/out transition which is present originally, but there is always a little moment where the background of the text area disappears, so we see the background image entirely. This little moment is really uncomfortable because it makes like a flash, but I didn’t found anything to remove it…

Has anyone an idea to change it ?

Here’s the code I’ve got for the moment about the background and text for the 2nd part :

body {
  text-align: center; 
  font-size: 100%;
  font-family: "Chalkboard","Marker felt", "lucida", sans-serif;
  text-transform: uppercase
  background-image: url("url of my image"); ;
  background-repeat: no-repeat; 
  background-size: 80em 60em;}

.advices {
  color: white;
  padding: 0em 3em 0em 4em;
  position: relative ;
	width: 80%;
	height: 500px;
  background-color: #433e49;
  border-radius: 60px;
  transition-property: text;
  transition-duration: 1s;

The .advices is a tag applied on all the passages of the 2nd part of my story.
I tried also with transition-property: none; and transition: none; but the result what the same, there was always this little flash.

I’m really sorry if my english isn’t perfect, I hope you’ll understand me ! The code isn’t perfect either, I learn while testing.

Thank you very much