You have a number of issues here but don’t despair
First, you should remove the inline-styles that you applied to your image in the HTML. Those inline-styles will always override the CSS styles, and it’ll just confuse you if you try to write CSS styles for the same element, but can’t see any effect.
Next, your CSS:
.responsive{
Max width: 500px; /* this should be max-width*/
width:90%;
Height: auto;} /* properties are never uppercase */
#figure{
width 100%;
Height:auto; /* properties are never uppercase */
align-items:center; /* this doesn't do anything because the figure is not a flex-container */
margin:auto auto;
grid-area: img-div; /* this doesn't do anything because you have no grid defined anywhere */
justify-content:center; /* this doesn't do anything because the figure is not a flex-container */
}
#image {
width: 90%;
height: auto;
max-width: 625px;
margin:2em auto 1em auto; /* this is what actually centers the image, but.... */
display:block;
position: absolute; /* ... this makes the image stick to the left corner of the figure element */
}