Voici une feuille de style faite pour rendre les exports Markdown > CSS plus jolis.
En rapport avec cet autre post : http://gregoire.surrel.org/links/?l3ILYw

<style>
/* #####################

CSS rules for all

##################### */

/ Text style /
html{
font-family: 'Georgia', serif;
}
h1,h2,h3,h4,h5,h6{
font-weight: normal;
color: #111;
line-height: 1em;
margin-bottom: 0.5em;
}
h4,h5,h6{ font-weight: bold; }
h2{ font-size:1.8em; margin-left: 7mm; }
h3{ font-size:1.5em; margin-left: 12mm; }
h4{ font-size:1.2em; margin-left: 16mm; }
h5{ font-size:1.0em; margin-left: 18mm; }
h6{ font-size:0.9em; margin-left: 20mm; }

p{
text-align: justify;
}

/ Tables, figures /
figure{
text-align:
center; margin: 0;
}
img{
max-width:100%;
padding: 8px;
display: block;
margin: auto;
}
figure > img {
border: 1px #DDD solid;
}
figcaption, caption{
font-style: italic;
margin: auto;
padding: 0;
border: 1px #AAA solid;
}
figcaption{
display: inline-block;
padding: 3px;
margin-top: -1px;
border-top: 1px #DDD solid;
background: white;
}
caption{
border-bottom-width: 0;
}
tbody{
border-top: 4px #AAA solid;
}
table{
border-collapse: collapse;
border-spacing: 0;
border: 1px #AAA solid;
margin: auto;
}
td, th{
vertical-align: top;
padding: 0 3pt;
}
tr ~ tr{
border-top: thin rgba(0, 0, 0, 0.05) solid;
}

/ Text blocks /
blockquote, pre{
margin: 0;
padding:0.1cm 1cm;
padding-left: 1em;
display: inline-block;
}
blockquote{
border-left: 0.5em #DDD solid;
border-radius: 12pt 4pt 4pt 12pt;
}
pre,code,kbd,samp{
font-family: monospace;
max-width: 85%;
white-space: pre-wrap;
word-wrap: break-word;
}
dl{
margin-left: 0.8cm;
}
dt{
font-style: italic;
}

/ Spacing glitches /
pre + figure, h1 + blockquote, figure + figure{
margin-top: 1cm;
}
li > p{
margin: 0.2em;
}

/ Title counters /
body{ counter-reset: ch1; }
h1{
counter-increment: ch1;
counter-reset: ch2;
}
h1:before { content: counter(ch1) " - "; }
h2{
counter-increment: ch2;
counter-reset: ch3;
}
h2:before { content: counter(ch1) "." counter(ch2) " - "; }
h3{
counter-increment: ch3;
}
h3:before { content: counter(ch1) "." counter(ch2) "." counter(ch3) " - "; }

#TOC{
counter-reset: ch1;
}
.title:before, .author:before , .date:before, .TOC-header:before{
content: "";
}

/* ########################

CSS rules for screen

######################## */

@media screen{

/ Media style /

html{
padding: 1cm;
background: #eee;
}

body{
background: #fff url(data:image/png;base64,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) no-repeat;
background-size: 256px;
background-position: 16px 16px;
font-family: Georgia, Palatino, 'Palatino Linotype', Times, 'Times New Roman', serif;
font-size: 16px;
line-height: 1.5em;
padding: 3cm 1cm;
margin: auto;
max-width: 62em;
min-width: 42em;
border: 1px black solid;
}

:target{ background: rgb(181, 230, 29); padding-left: 3mm; padding-right: 3mm; }

/ Document title /
header{
text-align: center;
}
.title{
border-bottom: 1px black solid;
}
.author{
margin: -1px 0 1cm;
margin-bottom: 1cm;
background: #eee;
display: inline-block;
padding: 10pt 15pt;
border: 1px black solid;
border-radius: 0 0 5pt 5pt;
border-top-width: 0;
}
.date{
font-variant: small-caps;
margin: 1cm 0 3cm;
}

/ Text style /

p{ margin:1em 0; }

h1{ font-size:2.5em; background:#eee; padding: 5pt; margin:1cm -1cm 0; border-top: 1px black solid; }

a{ color: #0645ad; text-decoration: none; border-bottom: 1px dotted #0645ad;}
h1 > a, h2 > a, h3 > a{ color: black; }
a:visited{ color: #0b0080; }
h1 > a:visited, h2 > a:visited, h3 > a:visited{ color: black; }
a:hover{ color: #06e; }
a:active{ color: #faa700; }
a:focus{ outline: 1px dotted; background: #fdca23}
a:hover, a:active{ outline: 0; }

/ Tables, figures /

figure > *{
box-shadow: 3px 3px 3px #ccc;
}

blockquote{
background: #EEE;
}

hr{
display: block;
height: 2px;
border: 0;
border-top: 1px solid #aaa;
border-bottom: 1px solid #eee;
margin: 1em 0;
padding: 0;
}

pre {
border: 1px #aaa solid;
border-radius: 5px;
background: #f8f8f8;
padding: 3pt;
margin-left: 1cm;
padding:0.1cm 1cm;
}

b, strong{ font-weight: bold; }

dfn{ font-style: italic; }

ins{ background: #ff9; color: #000; text-decoration: none; }

mark{ background: #ff0; color: #000; font-style: italic; font-weight: bold; }

sub, sup{ font-size: 75%; line-height: 0; position: relative; vertical-align: baseline; }
sup{ top: -0.5em; }
sub{ bottom: -0.25em; }

ul, ol{ padding: 0 0 0 2em; }
li { margin: 0 }
/p:last-child{ margin:0 }/
dd{ margin: 0 0 0 2em; }

td:nth-child(even), th:nth-child(even) { background: #F1F1F1 }

dt{ font-weight: bold; }
dl{ padding: 0 5mm; }

.footnotes{
background: #FDFCF2;
padding: 0 1em;
}
}

/* #######################

CSS rules for print

####################### */

@media print{
body{ font-size:12pt; max-width:100%; }
a{ text-decoration: underline; }
hr{ height: 1px; border:0; border-bottom:1px solid black; }
hr:after{ height: 1px; border:0; border-bottom:1px solid black; }
a[href]:after{ content: " (" attr(href) ")"; }
abbr[title]:after{ content: " (" attr(title) ")"; }
.ir a:after, a[href^="javascript:"]:after, a[href^="#"]:after{ content: ""; }
pre, blockquote{ border: 1px solid #999; padding-right: 1em; page-break-inside: avoid; }
tr, img{ page-break-inside: avoid; }
img{ max-width: 100% !important; }
@page :left{ margin: 15mm 20mm 15mm 10mm; }
@page :right{ margin: 15mm 10mm 15mm 20mm; }
p, h2, h3{ orphans: 3; widows: 3; }
h1, h2, h3{ page-break-after: avoid; }
}
</style>