* { box-sizing: border-box; }
body {
  font-family: "Public Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  margin: 0; color: #e6e6e6; background: #1a1a1a; line-height: 1.5;
}
a { color: #6cb6ff; text-decoration: underline; text-underline-offset: 2px; }
a:visited { color: #b39ddb; }
a:hover { color: #9ecbff; }
a:visited:hover { color: #cebcf5; }
a:active { color: #ffd479; }
a:focus-visible, button:focus-visible, input:focus-visible {
  outline: 2px solid #ffb56c; outline-offset: 2px; border-radius: 2px;
}
/* chrome-like links (nav, cards) carry their own affordance, so no underline */
header nav a, header nav a:visited, header h1 a, header h1 a:visited,
a.track-card, a.track-card:visited,
.lesson-nav a, .lesson-nav a:visited {
  text-decoration: none;
}
a.track-card:visited, header h1 a:visited { color: inherit; }
header nav a:visited { color: #cacaca; }
.lesson-nav a:visited { color: #6cb6ff; }
header {
  position: sticky; top: 0; z-index: 10;
  display: flex; align-items: center; gap: 1.5rem; flex-wrap: wrap;
  padding: 0.8rem 1.5rem; background: #232323; border-bottom: 1px solid #373737;
}
header h1 { font-size: 1.7rem; margin: 0; }
/* VT323 is a small-bodied pixel font, so headings get bumped ~1.5x */
h1, h2, h3, h4, .track-card .title {
  font-family: "VT323", "JetBrains Mono", ui-monospace, monospace;
  font-weight: 400;
}
header nav { display: flex; gap: 0.2rem; }
header nav a {
  padding: 0.4rem 0.75rem; border-radius: 6px; color: #cacaca;
  font-family: "VT323", "JetBrains Mono", ui-monospace, monospace;
  font-size: 1.35rem; font-weight: 400;
}
header nav a:hover { background: #313131; color: #e6e6e6; text-decoration: none; }
header h1 a { color: inherit; }
#search {
  flex: 1; min-width: 200px; max-width: 420px;
  padding: 0.45rem 0.8rem; border-radius: 6px; border: 1px solid #464646;
  background: #131313; color: inherit; font-size: 0.95rem;
}
main { max-width: 980px; margin: 0 auto; padding: 1.5rem; }
footer {
  padding: 2rem 1.5rem; color: #949494; text-align: center;
  font-family: "VT323", "JetBrains Mono", ui-monospace, monospace;
  font-size: 1.25rem;
  line-height: 1.2rem;
}
.track-card {
  display: block; padding: 1rem 1.2rem; margin: 0.6rem 0;
  background: #232323; border: 1px solid #373737; border-radius: 8px; color: inherit;
}
.track-card:hover { border-color: #ffb56c; }
.track-card:visited { color: inherit; }
.track-card .title { font-size: 1.6rem; font-weight: 400; color: #e6e6e6; }
.track-card .meta { color: #949494; font-size: 0.85rem; margin-top: 0.2rem; }
.badge {
  display: inline-block; padding: 0.1rem 0.5rem; border-radius: 3px;
  font-size: 0.72rem; vertical-align: middle; margin-left: 0.5rem;
  background: #353535; color: #aaaaaa; border: 1px solid #464646;
  font-family: "Public Sans", -apple-system, sans-serif; font-weight: 500;
}
.badge.rec { background: #1d3a2a; color: #8fd8a8; border-color: #2e5c40; }
.track-group { margin: 2.2rem 0 1rem; }
.track-group > h2 { font-size: 2.2rem; margin-bottom: 0.2rem; }
.group-desc { margin-top: 0.2rem; font-size: 0.92rem; }
.track-card .track-desc {
  color: #b5b5b5; font-size: 0.9rem; margin-top: 0.35rem; line-height: 1.45;
}
p.track-desc { font-size: 0.95rem; margin-top: -0.3rem; }
.unit { margin: 1.8rem 0 0.8rem; }
.unit > h2 {
  font-size: 1.6rem; color: #ffd29e; margin: 0 0 0.4rem;
  border-bottom: 1px solid #373737; padding-bottom: 0.3rem;
}
.section { margin: 0.9rem 0 0.9rem 1rem; }
.section > h3 { font-size: 1.45rem; color: #cacaca; margin: 0 0 0.3rem; }
.lessons { list-style: none; margin: 0; padding: 0 0 0 1rem; }
.lessons li { padding: 0.18rem 0; font-size: 0.92rem; }
.lessons li .repo { color: #949494; font-family: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 0.78rem; margin-left: 0.4rem; }
.lessons li .missing { color: #d99a9a; font-size: 0.75rem; margin-left: 0.4rem; }
.kind { color: #707070; font-size: 0.7rem; margin-left: 0.4rem; }
.dim { color: #949494; }
table.repos { width: 100%; border-collapse: collapse; font-size: 0.85rem; }
table.repos td, table.repos th { text-align: left; padding: 0.3rem 0.5rem; border-bottom: 1px solid #2c2c2c; }
table.repos tbody tr:nth-child(even) { background: #1f1f1f; }
table.repos thead tr { background: #232323; }
table.repos td.mono { font-family: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 0.8rem; }

/* --- rendered lesson content --- */
.lesson { max-width: 46rem; }
.lesson h1 { font-size: 2.4rem; }
.lesson h2 { font-size: 1.9rem; margin-top: 1.8rem; }
.lesson h3 { font-size: 1.6rem; }
.lesson h4 { font-size: 1.35rem; }
.lesson h1::before { content: "# "; color: #707070; }
.lesson h2::before { content: "## "; color: #707070; }
.lesson h3::before { content: "### "; color: #707070; }
.lesson h4::before { content: "#### "; color: #707070; }
.lesson h5::before { content: "##### "; color: #707070; }
.lesson h6::before { content: "###### "; color: #707070; }
.lesson img { max-width: 100%; }
.lesson iframe {
  display: block; width: 100%; max-width: 100%;
  height: auto; aspect-ratio: 16 / 9;
  border: 1px solid #373737; margin: 1rem 0;
  background: #131313;
}
.lesson code {
  background: #282828; padding: 0.1em 0.35em; border-radius: 4px;
  font-family: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 0.88em;
}
.lesson pre {
  position: relative;
  background: #131313; border: 1px solid #313131; border-radius: 8px;
  padding: 0.9rem 1rem; overflow-x: auto;
}
.copy-btn {
  position: absolute; top: 0.4rem; right: 0.4rem;
  padding: 0.25rem 0.7rem; border-radius: 6px; font-size: 0.75rem;
  border: 1px solid #464646; background: #282828; color: #949494;
  cursor: pointer; opacity: 0.75;
  font-family: inherit;
}
.lesson pre:hover .copy-btn, .lesson pre:focus-within .copy-btn { opacity: 1; }
.copy-btn:hover { border-color: #ffb56c; color: #e6e6e6; }
.copy-btn.copied { color: #7fd6a0; border-color: #2f5c40; }
.lesson pre code { background: none; padding: 0; }
.lesson pre code.hljs { background: transparent; padding: 0; color: #d1d1d1; }
.lesson blockquote {
  margin: 1rem 0; padding: 0.3rem 1rem;
  border-left: 3px solid #464646; color: #c0c0c0;
}
.lesson table { border-collapse: collapse; }
.lesson th, .lesson td { border: 1px solid #373737; padding: 0.35rem 0.7rem; }
.lesson thead tr { background: #232323; }
.lesson tbody tr:nth-child(even) { background: #1f1f1f; }
.lesson a { word-break: break-word; }

/* --- quiz blocks --- */
.quiz {
  border: 1px solid #464646; border-radius: 10px;
  padding: 1rem 1.2rem; margin: 1.2rem 0; background: #202020;
}
.quiz-q { margin: 0.8rem 0; }
.quiz-qtext { font-weight: 600; margin-bottom: 0.3rem; }
.quiz-opts { list-style: none; margin: 0; padding: 0 0 0 0.8rem; }
.quiz-opts li { padding: 0.15rem 0.5rem; border-radius: 4px; }
.quiz-opts li::before { content: "○ "; color: #949494; }
.quiz.show-answers .opt-correct {
  background: #14331f; color: #7fd6a0;
}
.quiz.show-answers .opt-correct::before { content: "✓ "; color: #7fd6a0; }
.quiz-toggle {
  margin-top: 0.6rem; padding: 0.3rem 0.9rem; border-radius: 6px;
  border: 1px solid #464646; background: #282828; color: #cacaca;
  cursor: pointer; font-size: 0.8rem;
}
.quiz-toggle:hover { border-color: #ffb56c; }

/* --- platform note + lab panel --- */
.platform-note {
  border: 1px solid #4a4235; border-top: 3px solid #d0a35f;
  background: #211d16;
  padding: 0.7rem 1rem; margin: 1rem 0; font-size: 0.9rem;
}
.platform-note summary { cursor: pointer; color: #ffd29e; margin-top: 0.3rem; }
.platform-note table { margin: 0.5rem 0 0.2rem; font-size: 0.85rem; }
.platform-note td { border: none; border-bottom: 1px solid #33302a; padding: 0.3rem 0.8rem 0.3rem 0; vertical-align: top; }

.lab-panel {
  border: 1px solid #59442f; border-top: 3px solid #ffb56c;
  background: #241e16;
  padding: 0.8rem 1.1rem; margin: 1.5rem 0; font-size: 0.9rem;
}
.lab-panel pre { margin: 0.6rem 0; }
.lab-panel summary { cursor: pointer; color: #ffd29e; }
.file-tree { list-style: none; padding-left: 0.4rem; columns: 2; column-gap: 2rem; }
.file-tree li { padding: 0.1rem 0; break-inside: avoid; }
.file-tree code { font-size: 0.8rem; }

/* --- lesson prev/next navigation --- */
.lesson-nav {
  display: flex; align-items: center; justify-content: space-between;
  gap: 1rem; margin: 0.8rem 0; padding: 0.55rem 0.9rem;
  background: #232323; border: 1px solid #373737; border-radius: 8px;
  font-family: "VT323", "JetBrains Mono", ui-monospace, monospace;
  font-size: 1.3rem;
}
.lesson-nav .nav-prev { flex: 1; text-align: left; min-width: 0;
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.lesson-nav .nav-next { flex: 1; text-align: right; min-width: 0;
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.lesson-nav .nav-loc {
  flex: 0 1 auto; display: flex; flex-direction: column;
  text-align: center; min-width: 0; padding: 0 0.5rem;
}
.lesson-nav .nav-unit {
  color: #e6e6e6; font-size: 1.2rem; font-weight: 400;
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
}
.lesson-nav .nav-sec {
  color: #949494; font-size: 1.05rem;
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
}