Need help editing my CSS! I hit a roadblock and do not know how to move items on my page

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CSS Code
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body {
  font-family: 'Ubuntu', sans-serif;
}

#wrapper {
  max-width: 940px;
  margin:0 auto;
  padding: 0 5%;
}

a {
  text-decoration:none;
}

img {
  max-width: 100%;
}

h3 {
  margin:0 0 1em 0;
}



/*****************************
COLORS
*****************************/
/*Site Body*/
body {
  background-color:#fff;
  color:#999;
}

/*header color*/
header {
  background:steelblue;
  border-color: lightblue;
}

/*nav background on mobile devices*/
/*
nav {
  background:lightblue;
}
*/

/*logo text*/
h1, h2 {
  color: #fff;
}

/*links*/
a {
  color: steelblue;
}




/*****************************
HEADING
*****************************/

header {
  float:left;
  margin:0 0 30px 0;
  padding: 5px 0 0 0;
  width: 100%;
}

#logo {
  text-align: center;
  margin: 0;
}

h1 {
  font-family: 'Ubuntu', sans-serif;
  margin: 16px 0px;
  font-size: 2em;
  font-weight: bold;
}

h2 {
  font-size:.75em;
  margin:-5px 0 0;
  font-weight:bold;
}


/*****************************
NAVIGATION 
*****************************/

/*****************************
NAVIGATION *DROP-DOWN*
*****************************/
* {
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}
@font-face {
    font-family: 'icomoon';
    src:url('http://treehouse-code-samples.s3.amazonaws.com/CSS-DD/codepen/stage-13/fonts/icomoon.eot');
    src:url('http://treehouse-code-samples.s3.amazonaws.com/CSS-DD/codepen/stage-13/fonts/icomoon.eot?#iefix') format('embedded-opentype'),
        url('http://treehouse-code-samples.s3.amazonaws.com/CSS-DD/codepen/stage-13/fonts/icomoon.woff') format('woff'),
        url('http://treehouse-code-samples.s3.amazonaws.com/CSS-DD/codepen/stage-13/fonts/icomoon.ttf') format('truetype'),
        url('http://treehouse-code-samples.s3.amazonaws.com/CSS-DD/codepen/stage-13/fonts/icomoon.svg#icomoon') format('svg');
}
body {
    margin: 0;
    background: #ecf0f1;
    color: #fff;
    font-family: sans-serif;
    line-height: 1.5;
}
ul {
  list-style: none;
  padding: 0;
  margin: 0; 
}
.main-header {
  margin: auto;
  width: 100%;
  min-height: 90px;
  padding: 1em 2em;
  border: 2px solid #2675a9;
  border-top: none;
  border-radius: 0 0 5px 5px;
    background: #2980b9;
}
  .main-header:after {
    content: " ";
    display: table;
    clear: both;
  }
.logo {
    display: block;
    text-decoration: none;
  float: left;
  margin-top: 5px;
}
  .logo::before {
    color: #fff;
    content: "\e001";
    font-weight: normal;
    font-style: normal;
    font-size: 2.5em;
    font-family: "icomoon";
    -webkit-font-smoothing: antialiased;
  }

/* Nav Demo Styles -------------------- */

.main-nav,
.drop-nav {
  background: #2c3e50;
}
.main-nav {
  float: left;
  border-radius: 4px;
  margin-top: 8px;
  border: solid 1px #1e2a36;
}
  .main-nav > li {
    float: left;
    border-left: solid 1px #1e2a36;
  }
  .main-nav li:first-child {
    border-left: none;
  }
  .main-nav a {
    color: #fff;
    display: block;
    padding: 10px 30px;
    text-decoration: none;
  }


.dropdown,
.flyout {
  position: relative;
}
.dropdown:after {
  font-size: .5em;
  display: block;
  position: absolute;
  top: 38%;
  right: 12%;
}
.drop-nav,
.flyout-nav {
  position: absolute;
  display: none;
}
.drop-nav li {
  border-bottom: 1px solid rgba(255,255,255,.2);
}
.dropdown:hover > .drop-nav,
.flyout:hover > .flyout-nav {
  display: block;
}
.flyout-nav {
  left: 100%;
  top: 0;
}
.flyout:hover a,
.flyout-nav {
  background: #395066;
}

.main-nav li:hover, .dropdown li:hover, .drop-nav li:hover {
  background-color:black;
}


/*****************************
FOOTER
*****************************/

footer {
  font-size:0.75em;
  text-align:center;
  clear:both;
  padding-top:50px;
  color:#CCC;
}


/*****************************
PAGE: HOME
*****************************/

#gallery {
  margin:0px auto;
  padding:0;
  text-align:center;
  list-style:none;
}
#gallery li {
  float:left;
  width:45%;
  margin:2.5%;
  background-color: #f5f5f5;  /* oval roman numeral color */
  color: #bdc3c7;
}

#gallery li a p {
  margin:0;
  padding:5%;
  font-size:1em;
  font-weight:bold;
  color: #bdc3c7;
}


.saber_styles {
  display:block;
  max-width:150px;
  margin:0 auto 30px;
  border-radius:100%;
}


h3 {
  margin:0 12% 0% 12%;
  border: 2px solid;
  color: black;
  text-align:center;
}