/* Course-local styles. The design system is /assets/css/idst.css on idst.uk;
   this file only adds what markdown content and the course chrome need on top
   of it: code, tables, the contents dropdown, the session pager and the cards. */

/* The site nav is sticky and about 63px tall, so an anchor jump would land a
   heading underneath it. Same rule every sub-site carries. */
:target { scroll-margin-top: 5rem; }

/* ---------- markdown prose ---------- */

.prose.course .wrap { padding-bottom: 1rem; }
.prose.course h1 { margin-bottom: 1.2rem; }
.prose.course h2 { margin-top: 3rem; padding-top: 1.4rem; border-top: 1px solid var(--rule-soft); }
.prose.course h3 { margin-top: 2rem; margin-bottom: 0.6rem; }
.prose.course h4 { font-family: var(--display); font-variation-settings: "wght" 700, "wdth" 92;
  font-size: 1.02rem; margin-top: 1.6rem; margin-bottom: 0.4rem; }
.prose.course p, .prose.course li { max-width: 68ch; }
.prose.course ol { padding-left: 1.2rem; display: grid; gap: 0.5rem; }
.prose.course li > ul, .prose.course li > ol { margin-top: 0.5rem; }
.prose.course hr { border: 0; border-top: 1px solid var(--rule); margin: 2.6rem 0; }
.prose.course strong { color: var(--ink); font-variation-settings: "wght" 600; }
.prose.course img { margin: 1.4rem 0; box-shadow: 0 0 0 1px var(--rule-soft); }

.prose.course a { color: var(--accent); text-underline-offset: 0.18em; }
.prose.course a:hover { color: var(--ink); }

.prose.course code {
  font-family: var(--mono); font-size: 0.86em; background: var(--bg-sink);
  padding: 0.12em 0.36em; border-radius: 3px; color: var(--ink);
  overflow-wrap: anywhere;
}
.prose.course pre {
  background: var(--ink); color: #f4f2ee; padding: 1.1rem 1.2rem; margin: 1.3rem 0;
  overflow-x: auto; font-size: 0.84rem; line-height: 1.55; max-width: none;
}
.prose.course pre code { background: none; padding: 0; color: inherit; font-size: inherit; }

.prose.course blockquote {
  margin: 1.6rem 0; padding: 1.1rem 1.3rem; background: var(--accent-sink);
  border-left: 3px solid var(--accent);
}
.prose.course blockquote p { margin: 0; max-width: none; }
.prose.course blockquote p + p { margin-top: 0.7rem; }

/* Tables are the one thing that will not fit 68ch, so they scroll in place
   rather than pushing the page sideways. */
.prose.course table {
  width: 100%; border-collapse: collapse; margin: 1.4rem 0; font-size: 0.9rem;
  display: block; overflow-x: auto;
}
.prose.course th, .prose.course td {
  border-bottom: 1px solid var(--rule-soft); padding: 0.6rem 0.8rem 0.6rem 0;
  text-align: left; vertical-align: top; color: var(--dim);
}
.prose.course th {
  font-family: var(--mono); font-size: 0.68rem; letter-spacing: 0.06em;
  text-transform: uppercase; color: var(--muted); border-bottom-color: var(--rule);
  white-space: nowrap;
}

/* ---------- course chrome ---------- */

.badge {
  display: inline-block; font-family: var(--mono); font-size: 0.66rem;
  letter-spacing: 0.08em; text-transform: uppercase; color: var(--muted);
  border: 1px solid var(--rule); padding: 0.3rem 0.7rem; margin-bottom: 1.4rem;
}
.badge.tutor-badge { color: var(--accent); border-color: var(--accent); }

.coursenav { border-bottom: 1px solid var(--rule-soft); background: var(--bg-sink); }
.coursenav summary {
  cursor: pointer; list-style: none;
  max-width: 1180px; margin-inline: auto; padding: 0.85rem clamp(20px, 5vw, 48px);
  font-family: var(--mono); font-size: 0.7rem; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--muted);
}
.coursenav summary::-webkit-details-marker { display: none; }
.coursenav summary::after { content: " +"; color: var(--accent); }
.coursenav[open] summary::after { content: " −"; }
.coursenav summary:hover { color: var(--ink); }
.coursenav nav { display: grid; gap: 1.6rem; padding-bottom: 1.8rem; }
@media (min-width: 700px)  { .coursenav nav { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 1000px) { .coursenav nav { grid-template-columns: repeat(4, 1fr); } }
.coursenav nav a { display: block; font-size: 0.88rem; color: var(--dim); padding: 0.16rem 0; }
.coursenav nav a:hover { color: var(--accent); }
.nav-group {
  font-family: var(--mono); font-size: 0.64rem; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--ink); margin: 0 0 0.5rem;
}

.pager {
  display: flex; justify-content: space-between; align-items: center; gap: 1rem;
  margin-top: 3.4rem; padding-top: 1.4rem; border-top: 1px solid var(--rule);
  font-size: 0.9rem;
}
/* Scoped under .prose.course, because the generic `.prose.course a` colour
   rule outranks a bare `.pager a` and would paint the Homework pill's label
   accent-on-accent, i.e. invisible. */
.prose.course .pager a { color: var(--dim); }
.prose.course .pager a:hover { color: var(--accent); }
.pager .prev::before { content: "← "; }
.pager .next::after { content: " →"; }
.prose.course .pager .hw {
  background: var(--accent); color: var(--on-accent); padding: 0.5rem 1rem;
  border-radius: 999px; font-size: 0.84rem;
}
.prose.course .pager .hw:hover { background: var(--ink); color: var(--on-accent); }
.pager .hw::after { content: " →"; }

/* ---------- the course home page ---------- */

.course-hero { padding-block: clamp(2.4rem, 6vh, 4rem) 0; }
.card-grid { display: grid; gap: 0; margin: 1.2rem 0 2rem; }
/* Two columns, not three: the content column is .wrap.narrow at 760px, so a
   third column would leave each card too narrow to hold a session subtitle. */
@media (min-width: 620px) { .card-grid { grid-template-columns: repeat(2, 1fr); } }
.card-grid a.card {
  display: flex; flex-direction: column; gap: 0.35rem;
  background: var(--bg); padding: 1.2rem 1.2rem 1.3rem;
  box-shadow: 0 0 0 1px var(--rule-soft);
  font-family: var(--display); font-variation-settings: "wght" 700, "wdth" 86;
  font-size: 1.06rem; letter-spacing: -0.02em; color: var(--ink); line-height: 1.2;
}
.card-grid a.card:hover { background: var(--bg-sink); color: var(--accent); }
.card-kicker {
  font-family: var(--mono); font-size: 0.63rem; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--accent);
  font-variation-settings: normal;
}
.card-sub {
  font-family: var(--body); font-variation-settings: "wght" 400;
  font-size: 0.86rem; line-height: 1.45; letter-spacing: 0; color: var(--dim);
}

/* ---------- image lightbox (site/js/img-zoom.js) ---------- */

.img-zoom { position: relative; display: block; }
.img-zoom-btn {
  position: absolute; right: 0.6rem; bottom: 0.6rem; width: 2rem; height: 2rem;
  border: 1px solid var(--rule); background: var(--bg); color: var(--dim);
  cursor: pointer; font-size: 0.9rem; line-height: 1;
}
.img-zoom-btn:hover { border-color: var(--ink); color: var(--ink); }
.img-zoom-overlay {
  display: none; position: fixed; inset: 0; z-index: 60;
  background: rgba(22, 21, 26, 0.94);
}
.img-zoom-overlay.open { display: flex; flex-direction: column; }
.img-zoom-stage { flex: 1; overflow: auto; display: flex; align-items: flex-start; justify-content: center; }
.img-zoom-overlay img { max-width: none; box-shadow: none; margin: 0; }
.img-zoom-bar { display: flex; gap: 0.4rem; padding: 0.7rem; }
.img-zoom-bar-top { justify-content: flex-end; }
.img-zoom-bubble {
  position: fixed; left: 50%; bottom: 1.2rem; transform: translateX(-50%);
  background: var(--bg); box-shadow: 0 0 0 1px var(--rule); border-radius: 999px;
}
.img-zoom-bar button {
  min-width: 2.1rem; height: 2.1rem; border: 0; border-radius: 999px;
  background: transparent; color: var(--dim); cursor: pointer; font-size: 0.95rem;
}
.img-zoom-bar-top button { background: var(--bg); }
.img-zoom-bar button:hover { background: var(--accent); color: var(--on-accent); }