Main Wrapper won't modify??

Hi every one, i cannot change in css the margin or the size of my wrapper.

Here is my css (in the child theme):

#wrapper {
width: 1000px;
margin: 0px auto;
position: relative;
border: transparent;
background-color: #EDF3E6;
padding-left: 10px;

}

the width and the margin wont work, if i change the values nothing happen…and i really need to set the margin to zero