:root { color-scheme: light; }
html { background: #fff; }
body {
  font-family: Verdana, Geneva, sans-serif;
  font-size: 13px;
  line-height: 1.62;
  color: #000;
  background: #fff;
  margin: 0;
  padding: 0;
}

/* ---- the mark -------------------------------------------------------
   Vitruvian figure pinned to the upper left; .page keeps a lane clear
   for it so it never sits on top of the first box. ------------------- */
.mark {
  position: fixed;
  top: 20px;
  left: 20px;
  z-index: 2;
  display: block;
  width: 74px;
  opacity: .9;
}
.mark img { width: 100%; height: auto; display: block; }

.page {
  display: flex;
  align-items: flex-start;
  gap: 20px;
  padding: 20px 20px 20px 114px;
  overflow-x: auto;
  height: 100vh;
  box-sizing: border-box;
}
/* .page.right, content packs to the top right, aside falls to its left */
.page.right { flex-direction: row-reverse; justify-content: flex-start; }
.box {
  border: 1px solid #000;
  padding: 28px 30px 30px;
  width: 500px;
  flex: 0 0 500px;
  height: 100%;
  overflow-y: auto;
  box-sizing: border-box;
  background: transparent;
}
/* .box.wide, room for a 550px embed to render at its native width */
.box.wide { width: 612px; flex-basis: 612px; }
h1 { font-size: 15px; font-weight: bold; margin: 0 0 4px; }
.sub { color: #555; margin: 0 0 28px; }
.code { color: #555; font-style: italic; margin: 0 0 20px; }
.aside { width: 300px; flex: 0 0 300px; }
.quote { font-style: italic; color: #555; margin: 0 0 18px; }
.quote.cont { margin-bottom: 10px; }
.quote .by { display: block; font-style: normal; margin-top: 4px; }
ol { padding-left: 26px; margin: 0; }
li { margin-bottom: 5px; }
li .c { display: block; color: #777; font-style: italic; }
a { color: #000; }
a:visited { color: #555; }
a:hover { color: #666; }
p { margin: 0 0 14px; }
.nav { margin: 0 0 28px; }
.nav a { color: #555; text-decoration: none; }
.nav a:hover { text-decoration: underline; }
.foot { margin-top: 32px; color: #555; }
.feed .box > .foot { margin-top: 18px; }
.foot a { color: #555; }
hr { border: none; border-top: 1px solid #ddd; margin: 32px 0; }

/* one <figure class="model"> per page, the physical model behind the idea */
.model { margin: 0 0 26px; }
.model img { width: 100%; height: auto; display: block; }
.model figcaption { color: #555; font-style: italic; font-size: 12px; margin-top: 7px; }

/* .feed, a column of boxes, newest first, scrolling as one timeline */
.feed {
  display: flex;
  flex-direction: column;
  gap: 20px;
  flex: 0 0 auto;
  height: 100%;
  overflow-y: auto;
}
.feed .box { width: 100%; height: auto; flex: 0 0 auto; overflow-y: visible; }
.feed .vid { margin: 0; }
/* each feed sets its own lane width; the columns scroll independently */
.feed.videos { width: 400px; }
.feed.models { width: 480px; }
.feed.wide   { width: 612px; }
.feed .thumb { display: block; margin-top: 14px; }
.feed .thumb img { width: 100%; height: auto; display: block; }
h2 { font-size: 15px; font-weight: bold; margin: 0 0 4px; }
h2 a { text-decoration: none; }
h2 a:hover { text-decoration: underline; }
.card .code { margin: 0; }

/* a card is a door: say so, and look clickable */
.card { cursor: pointer; }
.card:hover { border-color: #000; }
.card .open { color: #555; font-style: italic; font-size: 12px; margin: 12px 0 0; text-align: right; }
.card:hover .open { color: #000; }
.back { color: #555; text-decoration: none; }
.back:hover { text-decoration: underline; }

/* one <div class="vid"> per video, caption, then the embed */
.vid { margin: 0 0 26px; }
.vid:last-child { margin-bottom: 0; }
.vid .cap { color: #555; font-style: italic; margin: 0 0 8px; }
.vid .twitter-tweet { margin: 0 !important; }
.vid video { width: 100%; display: block; }

@media (max-width: 560px) {
  .page { height: auto; padding: 12px; overflow-x: visible; flex-direction: column; }
  .mark { position: static; width: 56px; margin: 12px 0 0 12px; }
  .page.right { flex-direction: column; }
  .box { width: 100%; flex: 1 1 auto; height: auto; overflow-y: visible; padding: 22px 18px 24px; }
  .box.wide { width: 100%; flex-basis: auto; }
  .feed, .feed.videos, .feed.models, .feed.wide { width: 100%; height: auto; overflow-y: visible; }
}