/* Universal Selector */

* {
    /* Includes padding and borders in width and height of all elements */
    box-sizing: border-box;
    padding: 0;
    margin: 0;
}

/* ID Selector */

#nav-main {
    /* Styles and positions all items in the nav element and floats it to the right of the page */
    padding-top: 15px;
    margin-right: 20px;
    float: right;
    font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
    font-size: 20px;
}

/* Element Selectors */

body {
    /* body background colour*/
    background-color: #d9dcd6;
}

header {
    /* Styling for header - dictates positioning, size, font, background colour and text colour */
    padding: 20px;
    font-family: 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande', 'Lucida Sans', Arial, sans-serif;
    background-color: #2a607c;
    color: #ffffff;
}

header h1 {
    /* Company logo size and positioning */
    display: inline;
    font-size: 48px;
}

header h1 .seo {
    /* Styles letters "seo" in company logo */
    color: #d9dcd6;
}

header nav ul {
    /* Removes list markers from navigation */
    list-style-type: disc;
}

header nav ul li {
    /* Adds space between each navigation element and displays them side by side */
    display: inline;
    margin-left: 25px;
}

a {
    /* Link colour and style */
    color: #ffffff;
    text-decoration: none;
}

p {
    /* P tag text size */
    font-size: 16px;
}

footer {
    /* Positioning and styling for footer and ensures no floating elements
    on either side */ 
    padding: 30px;
    clear: both;
    font-family: 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande', 'Lucida Sans', Arial, sans-serif;
    text-align: center;
}

footer h4 {
    /* footer text size */
    font-size: 20px;
}

/* Class selectors */

.background {
    /* Positioning, sizing and location of background image */
    height: 800px;
    width: 100%;
    margin-bottom: 25px;
    background-image: url("../images/digital-marketing-meeting.jpg");
    background-size: cover;
    background-position: center;
}

.sr-only {
    /* Visually hides screen-readable version of .background image */
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
  }

.float-left {
    /* Defines positioning for all elements with the .float-left class selector */
    float: left;
    margin-right: 25px;
}

.float-right {
    /* Defines positioning for all elements with the .float-right class selector */
    float: right;
    margin-left: 25px;
}

.content {
    /* Position and size for main content section */
    width: 75%;
    display: inline-block;
    margin-left: 20px;
}

.article-main {
    /* Position, size and styling for each article in main content section */
    margin-bottom: 20px;
    padding: 50px;
    height: 300px;
    font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
    background-color: #0072bb;
    color: #ffffff;
}

.article-main img {
    /* sets size of each image inside article elements */
    max-height: 200px;
}

.article-main h2 {
    /* Text styling for article headings */
    margin-bottom: 20px;
    font-size: 36px;
}

.benefits {
    /* Size, style and positioning for aside element - floats to the right and
    ensures no other floating elements either side */
    margin-right: 20px;
    padding: 20px;
    clear: both;
    float: right;
    width: 20%;
    height: 100%;
    font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
    background-color: #2589bd;
}

.benefit-content {
    /* colour and position of text sections within aside element */
    margin-bottom: 32px;
    color: #ffffff;
}

.benefit-content h3 {
    /* Aside element header positioning */
    margin-bottom: 10px;
    text-align: center;
}

.benefit-content img {
    /* Aside element image positioning and size */
    display: block;
    margin: 10px auto;
    max-width: 150px;
}