/* Reset, from
   http://meyerweb.com/eric/tools/css/reset/
   v2.0 | 20110126
*/

html, body, div, span, applet, object, iframe, h1, h2, h3, h4, h5, h6, p,
blockquote, pre, a, abbr, acronym, address, big, cite, code, del, dfn, em, img,
ins, kbd, q, s, samp, small, strike, strong, sub, sup, tt, var, b, u, i, center,
dl, dt, dd, ol, ul, li, fieldset, form, label, legend, table, caption, tbody,
tfoot, thead, tr, th, td, article, aside, canvas, details, embed,figure,
figcaption, footer, header, hgroup, menu, nav, output, ruby, section, summary,
time, mark, audio, video {
    margin: 0;
    padding: 0;
    border: 0;
    font-size: 100%;
    font: inherit;
    vertical-align: baseline;
}
/* HTML5 display-role reset for older browsers */
article, aside, details, figcaption, figure,
footer, header, hgroup, menu, nav, section, pre code {
    display: block;
}
body {
    line-height: 1;
}
ol, ul {
    padding-left: 1rem;
    list-style: disc;
}
blockquote, q {
    quotes: none;
}
blockquote:before, blockquote:after, q:before, q:after {
    content: '';
    content: none;
}
table {
    border-collapse: collapse;
    border-spacing: 0;
}
/* end reset */

html {
    /* background-image:url(../img/2.png); */
    /* background-repeat: no-repeat; */
    /* background-position: center top; */
    /* background-origin: content-box; */
    width : 100%;
    height: 100%;
}

/* colors */
#clear{
    clear: both;
}

/* article */
/* .art { */
/*     display: inline-block; */
/*     margin : 25px; */
/*     float  : top left; */
/* } */
/* #art1 { */
/*     width:450px; */
/*     height: 500px; */
/*     border: solid black 1px; */
/* } */

/* #art2 { */
/*     width: 450px; */
/*     height: 500px; */
/*     border: solid green 1px; */
/* } */
/* #art3 { */
/*     width: 250px; */
/*     height: 500px; */
/*     border: solid red 1px; */
/* } */


nav a:hover {
    color           : black;
    background-color: #44aaff;
}

nav a:visited {
    color: black;
}

footer, pre code {
    background-color: #ddd;
}

nav a {
    color: black;
    /* http://colorzilla.com/gradient-editor/#bee2f4+0,7db9e8+100&1+0,0.2+100 */
    /* FF3.6-15 */
    background: -moz-linear-gradient(top,
                                     rgba(190,226,244,1  )   0%,
                                     rgba(125,185,232,0.2) 100%);
    /* Chrome10-25,Safari5.1-6 */
    background: -webkit-linear-gradient(top,
                                        rgba(190,226,244,1  )   0%,
                                        rgba(125,185,232,0.2) 100%);
    /* W3C, IE10+, FF16+, Chrome26+, Opera12+, Safari7+ */
    background: linear-gradient(to bottom,
                                rgba(190,226,244,1  )   0%,
                                rgba(125,185,232,0.2) 100%);
    width      : 225px;
    border     : solid #3eb6f2 1px;
    font-weight: bold;
}
a {
    color: #22a;
}
a:visited {
    color: #606;
}
a:hover {
    color: #05f;
}

/* fonts */
code {
    font-family: monospace;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif, "Apple Color Emoji",
    "Segoe UI Emoji", "Segoe UI Symbol";
    background-color:rgba(255,255,255,0.8);
}
strong {
    font-weight: bold;
}
em {
    font-style: italic;
}

/* non-main elements */

header h1 {
    font-size: 3.5rem;
    margin-bottom: 0.6rem;
}

header #logo {
    float: right;
}

footer {
    padding: 0.4rem;
    border-radius: 0.4rem;
}

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

nav a {
    display: block;
    border-radius: 0.4rem;
    margin-bottom: 0.3rem;
    padding: 0.2rem 0.4em 0.2rem 0.4rem;
    text-decoration: none;
}

nav ul ul {
    padding: 0 0 0 2rem;
}

/* code blocks */
pre code {
    padding      : 0.5rem;
    border-radius: 0.5rem
}

/* vertical rythm */
body {
    font-size: 16px;
    line-height: 1.5rem;
}

h1 {
    font-size: 2.7rem;
    line-height: 3rem;
    margin: 0 0 1.5rem 0;
}
h2 {
    font-size: 2rem;
    line-height: 2rem;
    margin: 0 0 1rem 0;
}
h3 {
    font-size: 1.4rem;
    line-height: 1.5rem;
    margin: 0 0 0 0;
}
p, ul, ol, pre code {
    margin: 0 0 1.5rem 0;
}

/* desktop layout */
body {
    max-width: 1250px;
    margin: 0 auto 0 auto;
    display: flex;
    flex-direction: column;
}
header {
    flex: none;
    margin: 0 1rem 1rem 1rem;
}
footer {
    flex: none;
    margin: 1rem 1rem 1rem 1rem;
}
.center {
    display: flex;
    flex: 1;
    padding: 0 1rem 0 1rem;
}
nav {
    order: -1;
    flex: 0 0 18rem;
    margin: 0 1rem 0 0;
}
article {
    flex: 1;
}

/* mobile layout */
@media (max-width:1000px) {
    header h1 {
        font-size: 2.8rem;
        margin-bottom: 0.2rem;
    }
    body {
        max-width: 100%;
        margin: 1 0 1 0;
        flex-direction: column;
    }
    .center {
        flex-direction: column;
    }
    nav {
        order: 1;
        flex: 0 0 auto;
        margin: 1rem 0 0 0;
    }
}