* {
box-sizing: border-box;
}
body {
font-family: Arial, sans-serif;
margin: 0;
padding: 0;
background-color: #d0e0f0;
}
header {
background-color: #00c853;
color: #ffffff;
padding: 20px;
text-align: center;
}
header h1 {
margin: 0;
}
nav ul {
padding: 0;
}
nav ul li {
list-style: none;
display: inline;
margin-left: 20px;
}
nav ul li a {
color: #ffffff;
text-decoration: none;
}
.articles {
margin: 30px;
}
article {
background-color: #ffffff;
margin-bottom: 20px;
padding: 20px;
border-radius: 5px;
width: 90%;
text-align: justify;
}
div.sidebar {
background-color: #00c853;
color: #ffffff;
text-align: center;
padding: 10px;
position: fixed; right: 0; top: 0;
bottom: 0;
width: 150px; height: 100%;
}
h1 {
font-size: 36px;
font-weight: bold;
color: #333;
text-transform: uppercase;
}
h2 {
font-size: 30px;
font-weight: bold;
color: #555;
margin-top: 20px;
}
h3 {
font-size: 24px;
font-weight: normal;
color: #777;
margin-top: 15px;
}
h4 {
font-size: 18px;
font-weight: normal;
color: #999;
margin-top: 10px;
}
hr.green { border: 4px solid green; margin: }
.toc { background: #f0f8f0; padding: 15px; border: 2px solid green; }
.back { display: block; }
header {
width: calc(100% - 150px);
}
header center {
display: flex;
flex-wrap: wrap;
justify-content: center;
}
header center a {
margin: 6px;
}
header center br {
display: none;
}
@media only screen and (max-width: 1500px) {
article {
width: calc(100% - 150px);
margin-right1: 150px;
box-sizing: border-box;
}
header center {
position: relative;
z-index: 1;
}
}
@media only screen and (max-width: 992px) {
body {
display: flex;
flex-wrap: wrap;
}
header {
order: 1;
}
main {
order: 3;
}
body div.sidebar {
order: 2;
position: sticky;
width: 100%;
left: 0px;
}
.sidebar > br {
display: none;
}
.sidebar center br {
display: none;
}
.sidebar center a {
padding: 0px 10px;
}
article {
width: 100%;
}
h1 {
font-size: 32px;
}
 header {
width: 100%;
}
}
@media only screen and (max-width: 520px) {
header {
padding: 10px;
}
 h1 {
font-size: 22px;
text-align: center;
}
h2 {
font-size: 20px;
text-align: center;
}
.articles {
margin: 10px;
}
article {
padding: 10px;
}
}
@media only screen and (max-width: 992px) {
html {
scroll-padding-top: 90px;
}
}
@media only screen and (max-width: 520px) {
html {
scroll-padding-top: 100px;
}
}