/* GENERAL STYLE RULES */

/* apply a natural box layout model to all elements, but allowing components to change */

html{
  box-sizing: border-box;
}
*, *:before, *:after {
  box-sizing: inherit;
}

body {
  padding: 0;
  margin: 0;
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
}

.flex-container {
  display: flex;
}

.left {
  float: left;
}

.right {
  float: right;
}

/* TOP NAVIGATION STYLE RULES */
nav {
  padding: 10px;
  overflow: auto;
}

nav ul {
  list-style: none;
  padding-left: 0;
  margin: 0;
}

nav a {
  display: block;
  padding: 10px 20px;
}

/* MAIN HEADER STYLE RULES */
header {
  height: 280px;
  padding: 20px;
}

/* MAIN CONTENT AND ASIDE AREA STYLE RULES */
main, aside {
  padding: 12px;
}

main {
  width: 70%;
  margin-bottom: 20px;
}

article {
  padding-bottom: 20px;
}

aside {
  width: 30%;
}

aside section {
  padding: 0 10px;
  margin-bottom: 20px;
}

.subscription-form {
  padding: 10px;
}

input, select {
  width: 100%;
  height: 28px;
  margin-bottom: 10px;
}

.subscribe-button {
  display: block;
  margin-top: 20px;
}

/* FOOTER STYLE RULES */
footer {
  overflow: auto;
  padding: 10px;
}

footer p#copyright-text {
  line-height: 32px;
  vertical-align: middle;
}

footer ul#social-media {
  list-style: none;
  padding-left: 0;
  margin: 0;
}

footer ul#social-media li {
  margin: 16px;
  height: 32px;
  display: inline-block;
}

/* RESPONSIVE STYLE RULES FOR MOBILE DEVICES */
@media screen and (max-width: 690px) {

    .flex-container {
      flex-direction: column;
    }

    main, aside {
      width: 100%;
    }

}