How to Widen Post Width Content Area

I don’t know how to use that…

Here is the code that I used in my child theme, and I can’t figure out why it doesn’t work…

#page {
 max-width: 1200px;
}

Is it incompatible with my other code in my child theme?

#logo {
    float: none;
    margin: 0;
    text-align: center;
}

.menu { display: none;}

#page {
 max-width: 1200px;
}

.home #container { max-width: 100%; } .home #header { margin: 0 auto; max-width: 1060px; } .home-widgets { max-width: 1060px; margin: 0 auto; }

@media screen and (min-width: 1200px) {
/* Menu bar */
.menu {
	background-color: #C3BEAE;
background-image: -webkit-gradient(linear, left top, left bottom, from(#C3BEAE), to(#C3BEAE));
	background-image: -webkit-linear-gradient(top, #C3BEAE, #C3BEAE);
	background-image: -moz-linear-gradient(top, #C3BEAE, #C3BEAE);
	background-image: -ms-linear-gradient(top, #C3BEAE, #C3BEAE);
	background-image: -o-linear-gradient(top, #C3BEAE, #C3BEAE);
	background-image: linear-gradient(top, #C3BEAE, #C3BEAE);
	clear: both;
    filter: progid:DXImageTransform.Microsoft.gradient(startColorstr=#C3BEAE, endColorstr=#C3BEAE);

	margin: 0 auto;
}
/* Menu items */
.menu a {
	border-left: 1px solid #C3BEAE;
	color: #160F07;
	font-size: 15px;
	font-weight: 700;
        font-style: Garamond;
	height: 45px;
	line-height: 45px;
	padding: .5em;
}

/* Menu item hover */
.menu a:hover {
	background-color: #C3BEAE;
	background-image: -webkit-gradient(linear, left top, left bottom, from(#C3BEAE), to(#C3BEAE));
	background-image: -webkit-linear-gradient(top, #C3BEAE, #C3BEAE);
	background-image: -moz-linear-gradient(top, #C3BEAE, #C3BEAE);
	background-image: -ms-linear-gradient(top, #C3BEAE, #C3BEAE);
	background-image: -o-linear-gradient(top, #C3BEAE, #C3BEAE);
	background-image: linear-gradient(top, #C3BEAE, #C3BEAE);
	color: #fcfcfc;
    filter: progid:DXImageTransform.Microsoft.gradient(startColorstr=#C3BEAE, endColorstr=#C3BEAE);
}
/* Current page */
.menu .current_page_item a,
.menu .current-menu-item a {
	background-color: #C3BEAE;
}
/* Menu dropdown */
.menu li li {
	background: #fcfcfc;
	background-image: none;
	border: 1px solid #C3BEAE;
	color: #fcfcfc;
	filter: none;
    margin: -1px 0 1px 0;
	width: auto;
}
/* Menu dropdown hover */
.menu li li a:hover {
	background: #C3BEAE !important;
	background-image: none;
	border: none;
	color: #fcfcfc;
	filter: none;
}
}

.main-nav {
	width: 100%;
	position: absolute;
	left: 0;
	margin-top: -45px;
}
#header {
	margin-top: -15px;
}

@media screen and (min-width: 1200px) {
    .menu {
        text-align:center
    }
    .menu li {
        display:inline-block;
        float:none;
        margin-left: -5px;
    }
    .menu li li {
        display:block;
        text-align:left
    }
}

a {
color: #160F07;
}
.post-title {
line-height: 1.3em;
}