/* clownix.net: one stylesheet for the pages and the two books. No framework,
   no webfont, no javascript: system fonts, and the colours of the canvas,
   blue cables, grey lans, green and cyan interface dots. */

:root {
  --ink:      #16202a;
  --ink-2:    #51606e;
  --rule:     #d8dfe7;
  --wash:     #f0f4f8;
  --cable:    #1b63c6;
  --cable-dk: #0f3f86;
  --lan:      #3a4450;
  --sniff:    #13915a;
  --port:     #1fb1c7;
  --clown:    #d62d45;
  --code-bg:  #f3f6f9;
  --sans:  "Avenir Next", Avenir, "Segoe UI Variable Display", "Segoe UI",
           Ubuntu, Cantarell, "Noto Sans", "DejaVu Sans", Helvetica, Arial,
           sans-serif;
  --serif: Charter, "Bitstream Charter", "Charis SIL", "Sitka Text", Cambria,
           "Noto Serif", "DejaVu Serif", Georgia, serif;
  --mono:  ui-monospace, "SF Mono", "Cascadia Mono", "Segoe UI Mono",
           "DejaVu Sans Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; text-size-adjust: 100%; }

body {
  margin: 0;
  color: var(--ink);
  background: #fff;
  font: 17px/1.62 var(--serif);
}

a { color: var(--cable); text-underline-offset: 2px; }
a:hover { color: var(--cable-dk); }
:focus-visible { outline: 3px solid var(--port); outline-offset: 2px; }

.wrap { max-width: 960px; margin: 0 auto; padding: 0 24px; }

/* header: the name and the pages, over the blue line of a cable */
header { background: #fff; border-bottom: 3px solid var(--cable); }
nav {
  max-width: 960px; margin: 0 auto; padding: 12px 24px;
  display: flex; gap: 6px 20px; align-items: center; flex-wrap: wrap;
  font-family: var(--sans);
}
nav a { color: var(--ink-2); text-decoration: none; font-size: 15px;
        padding: 4px 0; border-bottom: 2px solid transparent; }
nav a:hover { color: var(--cable-dk); border-bottom-color: var(--rule); }
nav a.on { color: var(--ink); font-weight: 600;
           border-bottom-color: var(--sniff); }
nav .brand { color: var(--clown); font-weight: 700; font-size: 19px;
             margin-right: 10px; border: 0; }
nav .brand img { vertical-align: -7px; margin-right: 8px; }

/* the summary of the main page */
.hero { max-width: 960px; margin: 0 auto; padding: 52px 24px 38px; }
.hero .logo { display: block; max-width: 100%; height: auto; margin: 0 0 24px; }
.hero h1 { font: 700 44px/1.08 var(--sans); letter-spacing: -0.015em;
           margin: 0 0 18px; max-width: 18em; }
.lead { font-size: 20px; line-height: 1.55; color: var(--ink-2);
        margin: 0 0 26px; max-width: 38em; }
.cta { margin: 0 0 16px; }

/* three facts, each a way further in; the bullet is a sniffable port */
.facts { list-style: none; padding: 0; margin: 0 0 30px;
         display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px 30px; }
.facts li { position: relative; padding-left: 24px; font-size: 16px;
            line-height: 1.5; color: var(--ink-2); }
.facts li::before { content: ""; position: absolute; left: 1px; top: 0.4em;
                    width: 11px; height: 11px; border-radius: 50%;
                    background: var(--sniff); box-shadow: 0 0 0 3px #d5efe2; }
.facts a { color: inherit; text-decoration: none; }
.facts b { color: var(--ink); font-family: var(--sans); }
.facts a:hover b { color: var(--cable); }
.ver { font: 14px/1.5 var(--sans); color: var(--ink-2); margin: 0; }

.btn {
  display: inline-block; padding: 10px 18px; margin: 0 10px 10px 0;
  font: 600 15px/1.2 var(--sans); text-decoration: none;
  background: var(--cable); color: #fff; border: 2px solid var(--cable);
  border-radius: 4px;
}
.btn:hover { background: var(--cable-dk); border-color: var(--cable-dk);
             color: #fff; }
.btn.ghost { background: transparent; color: var(--cable); }
.btn.ghost:hover { background: var(--wash); color: var(--cable-dk); }

/* sections */
section { padding: 38px 0; }
section.top { padding-top: 44px; }
.band { background: var(--wash); border-top: 1px solid var(--rule);
        border-bottom: 1px solid var(--rule); }

h1, h2, h3 { font-family: var(--sans); color: var(--ink); }
h1 { font-size: 36px; line-height: 1.15; margin: 0 0 16px;
     letter-spacing: -0.01em; }
h2 { font-size: 26px; line-height: 1.2; margin: 38px 0 12px;
     letter-spacing: -0.005em; }
h3 { font-size: 18px; line-height: 1.3; margin: 0 0 8px; }
.wrap > h2:first-child { margin-top: 0; }
p  { margin: 0 0 14px; }
hr { border: 0; border-top: 1px solid var(--rule); margin: 40px 0; }
.wrap > p, .wrap > ul, .wrap > ol { max-width: 44em; }

.cols  { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; }
.cols2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.cols p, .cols2 p { font-size: 16px; color: var(--ink-2); }
.cols > *, .cols2 > *, .duo > *, .facts > * { min-width: 0; }
.wrap > h3 { margin: 28px 0 8px; }

/* a card is a plug: the coloured edge is the cable that leaves it */
.card { border: 1px solid var(--rule); border-top: 4px solid var(--cable);
        border-radius: 0 0 6px 6px; padding: 18px 22px 20px; background: #fff; }
.card.toy { border-top-color: var(--sniff); }
.note { font: 14px/1.5 var(--sans) !important; color: var(--ink-2) !important;
        margin-bottom: 0 !important; }

/* drawn or typed: the same network twice */
.duo { display: grid; grid-template-columns: 1fr 1fr; gap: 28px;
       align-items: center; margin: 6px 0 4px; }
.duo .canvas { border: 1px solid var(--rule); border-radius: 6px;
               background-color: #fbfcfd;
               background-image: radial-gradient(#d3dae2 1px, transparent 1px);
               background-size: 18px 18px; padding: 8px; }
.duo .canvas svg { display: block; width: 100%; height: auto; }
.duo pre { margin: 0; }
.duo .cap { font: 14px/1.5 var(--sans); color: var(--ink-2); margin: 10px 0 0; }

/* code */
pre {
  background: var(--code-bg); border: 1px solid var(--rule);
  border-left: 4px solid var(--lan); border-radius: 4px;
  padding: 14px 16px; overflow-x: auto; margin: 0 0 16px;
}
code { font: 14px/1.6 var(--mono); color: var(--cable-dk); }
p code, li code { overflow-wrap: anywhere; background: var(--code-bg); padding: 1px 5px;
                  border-radius: 3px; }

/* table */
table { border-collapse: collapse; width: 100%; margin: 8px 0 18px;
        font-family: var(--sans); }
th { text-align: left; font: 600 13px/1.4 var(--sans); color: var(--ink-2);
     padding: 6px 10px; border-bottom: 2px solid var(--rule); }
td { border-top: 1px solid var(--rule); padding: 9px 10px; font-size: 15px;
     line-height: 1.5; vertical-align: top; }
th + th, td + td { border-left: 0; }
td:first-child { width: 40%; color: var(--ink); }
td code { overflow-wrap: anywhere; }
td:last-child  { color: var(--ink-2); }
table.course td:first-child { width: 4%; }
table.course td:nth-child(2) { width: 20%; }
table.course td:nth-child(3) { width: 40%; }

/* figures */
.fig { width: 100%; height: auto; margin: 8px 0 12px; }
.fbox { fill: #f6f8fa; stroke: var(--cable-dk); stroke-width: 1.5; }
.facc { fill: #fdeef0; stroke: var(--clown); stroke-width: 1.5; }
.fzone { fill: #eef4fb; stroke: var(--cable); stroke-width: 1.5;
         stroke-dasharray: 7 4; }
.ft { font-size: 14px; font-family: var(--sans); fill: var(--ink); }
.fs { font-size: 11.5px; font-family: var(--sans); fill: var(--ink-2); }
.fm { font-size: 13px; font-family: var(--mono); fill: var(--cable-dk); }
.fz { font-size: 12px; font-weight: bold; font-family: var(--sans);
      fill: var(--cable); }
.farr { stroke: var(--cable); stroke-width: 2; fill: none;
        marker-end: url(#ar); }

/* the two books, sphinx body under the same header and footer */
.book section { padding: 0; }
.book p, .book li, .book dd { max-width: 44em; }
.book pre { font: 14px/1.6 var(--mono); color: var(--cable-dk); }
.book img { max-width: 100%; height: auto; margin: 8px 0 12px; }
.book a { color: var(--cable); }
.book h1 { margin-top: 10px; }
.book h2 { margin: 34px 0 10px; }
.book h3 { margin: 24px 0 8px; }
.book em { color: var(--cable-dk); }
.book li { margin: 0 0 4px; }
.book li p { margin: 0; }
.book blockquote { margin: 0 0 14px; }
.book dl.field-list { display: grid; grid-template-columns: max-content auto;
                      gap: 0 12px; margin: 0 0 18px; font: 14px/1.5 var(--sans);
                      color: var(--ink-2); }
.book dl.field-list dd { margin: 0; }
.book dl.field-list p { margin: 0; }
.book .toctree-wrapper ul { list-style: none; padding: 0; columns: 2; }
.book .toctree-wrapper li { padding: 5px 0; border-top: 1px solid var(--rule);
                            margin: 0; break-inside: avoid;
                            font-family: var(--sans); font-size: 15px; }
.book .toctree-wrapper a { text-decoration: none; }
.book td:first-child { width: auto; }
.book td p { margin: 0; }
.booknav { font: 14px/1.5 var(--sans); color: var(--ink-2); margin: 0 0 22px; }
.booknav a { text-decoration: none; }
.booknav:last-child { margin: 30px 0 0; padding-top: 14px;
                      border-top: 1px solid var(--rule); }

/* footer, the grey of a lan */
footer { background: var(--lan); padding: 26px 0; margin-top: 30px; }
footer p { font: 14px/1.5 var(--sans); color: #dfe5ec; margin: 0; }
footer a { color: #a9d6ff; }
footer a:hover { color: #fff; }

/* narrow screens */
@media (max-width: 760px) {
  .cols, .cols2, .facts, .duo { grid-template-columns: 1fr; gap: 22px; }
  .hero { padding: 36px 20px 30px; }
  .hero h1 { font-size: 32px; }
  .lead { font-size: 18px; }
  .wrap { padding: 0 20px; }
  td:first-child { width: 45%; }
  .book .toctree-wrapper ul { columns: 1; }
}