:root {
  --ink: #1f2a44; --accent: #c8553d; --second: #2a7f9e; --muted: #8a8f98;
  --paper: #fcfbf8; --panel: #f3f1ec; --rule: #e2dfd8; --text: #22262e;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
}
* { box-sizing: border-box; }
html { font-size: 17px; }
body { margin: 0; background: var(--paper); color: var(--text); font-family: var(--sans); line-height: 1.55; }
a { color: var(--second); text-decoration: none; }
a:hover { text-decoration: underline; }
code, pre { font-family: var(--mono); font-size: 0.86em; }
main { max-width: 1100px; margin: 0 auto; padding: 1.5rem 1rem 4rem; }

.site-header { display: flex; flex-wrap: wrap; gap: 1rem 1.5rem; align-items: center; padding: 0.8rem 1rem; border-bottom: 1px solid var(--rule); background: #fff; }
.site-header .brand { font-weight: 700; font-size: 1.25rem; color: var(--ink); letter-spacing: 0.01em; }
.site-header nav a { margin-right: 1rem; color: var(--ink); }
.site-header .search { margin-left: auto; display: flex; gap: 0.4rem; }
.site-header input[type=search] { padding: 0.4rem 0.6rem; border: 1px solid var(--rule); border-radius: 4px; min-width: 14rem; font-size: 0.95rem; }
.site-header button { padding: 0.4rem 0.8rem; border: 0; border-radius: 4px; background: var(--ink); color: #fff; font-size: 0.95rem; cursor: pointer; }
.site-footer { border-top: 1px solid var(--rule); padding: 1rem; color: var(--muted); font-size: 0.85rem; text-align: center; }

.browse { display: grid; grid-template-columns: 220px 1fr; gap: 2rem; }
@media (max-width: 760px) { .browse { grid-template-columns: 1fr; } }
.filters h3 { margin: 1rem 0 0.3rem; font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.08em; color: var(--muted); }
.filters ul { list-style: none; margin: 0; padding: 0; }
.filters li { display: flex; justify-content: space-between; padding: 0.1rem 0.3rem; border-radius: 3px; }
.filters li.active { background: var(--panel); font-weight: 600; }
.filters .count, .topic-list .count { color: var(--muted); font-size: 0.85rem; }
.active-filters { display: flex; flex-wrap: wrap; gap: 0.3rem; align-items: center; }
.chip { display: inline-block; padding: 0.1rem 0.55rem; border-radius: 999px; background: var(--panel); color: var(--ink); font-size: 0.85rem; }
.clear { font-size: 0.85rem; color: var(--muted); }
.result-count { color: var(--muted); margin-top: 0; }
.card { padding: 1rem 0; border-bottom: 1px solid var(--rule); }
.card h2 { margin: 0.2rem 0; font-size: 1.25rem; }
.card h2 a { color: var(--ink); }
.afterwards { margin: 0.2rem 0; }
.meta, .time { color: var(--muted); font-size: 0.9rem; }
.facets { margin: 0; display: flex; gap: 0.4rem; align-items: center; }
.badge { display: inline-block; padding: 0.05rem 0.5rem; border-radius: 3px; background: var(--panel); color: var(--ink); font-size: 0.8rem; }
.badge.type-concept { background: #e6eef3; color: var(--second); }
.badge.type-tool { background: #f6e3de; color: var(--accent); }
.badge.type-recipe { background: #e8e9ee; color: var(--ink); }
.empty { color: var(--muted); }

.tutorial { max-width: 760px; margin: 0 auto; }
.tutorial-header h1 { font-size: 2rem; line-height: 1.2; margin: 0.4rem 0 0.6rem; color: var(--ink); }
.tutorial-header .afterwards { font-size: 1.1rem; }
.header-facts { display: grid; grid-template-columns: max-content 1fr; gap: 0.2rem 1rem; margin: 1rem 0 2rem; padding: 0.8rem 1rem; background: var(--panel); border-radius: 6px; font-size: 0.92rem; }
.header-facts dt { color: var(--muted); }
.header-facts dd { margin: 0; }
.tutorial-body h2 { margin-top: 2.2rem; color: var(--ink); font-size: 1.45rem; }
.tutorial-body h3 { margin-top: 1.6rem; color: var(--ink); }
.tutorial-body img { max-width: 100%; height: auto; display: block; margin: 1rem auto; }
.tutorial-body table { border-collapse: collapse; margin: 1rem 0; }
.tutorial-body th, .tutorial-body td { border-bottom: 1px solid var(--rule); padding: 0.3rem 0.7rem; text-align: left; }
.tutorial-body .math { overflow-x: auto; }
.tutorial-body div.math { margin: 0.8rem 0; }
.tutorial-body :not(pre) > code { background: var(--panel); padding: 0.05rem 0.3rem; border-radius: 3px; }
.cell { margin: 1rem 0 1.4rem; }
.cell-input { position: relative; }
.cell-input pre { margin: 0; padding: 0.8rem 1rem; background: #f6f5f1; border-left: 3px solid var(--ink); border-radius: 0 4px 4px 0; overflow-x: auto; line-height: 1.45; }
.cell-input .copy { position: absolute; top: 0.4rem; right: 0.4rem; padding: 0.15rem 0.5rem; border: 1px solid var(--rule); border-radius: 3px; background: #fff; color: var(--muted); font-size: 0.75rem; cursor: pointer; opacity: 0.7; }
.cell-input:hover .copy { opacity: 1; }
.cell-outputs { margin-top: 0.4rem; }
pre.output { margin: 0.3rem 0; padding: 0.6rem 1rem; background: transparent; border-left: 3px solid var(--rule); overflow-x: auto; line-height: 1.4; white-space: pre; }
pre.output.stderr { border-left-color: var(--accent); color: #7a3b2e; }
pre.output.error { border-left-color: var(--accent); background: #fbeeea; }
img.output { margin: 0.6rem 0; }
details.code > summary, details.outputs > summary { cursor: pointer; color: var(--second); font-size: 0.9rem; margin-bottom: 0.3rem; }
pre.highlight code { background: none; padding: 0; }
.tutorial-body pre:not(.output):not(.highlight) { padding: 0.8rem 1rem; background: #f6f5f1; border-radius: 4px; overflow-x: auto; }
.tutorial-footer { margin-top: 3rem; padding-top: 1rem; border-top: 1px solid var(--rule); font-size: 0.92rem; }
.tutorial-footer .tags .chip { margin-right: 0.3rem; }
.feedback { color: var(--muted); }

.topic-list { list-style: none; padding: 0; }
.topic-list li { padding: 0.5rem 0; border-bottom: 1px solid var(--rule); }
.topic-list .summary { color: var(--muted); font-size: 0.92rem; }
.topic .summary { font-size: 1.1rem; }
.matrix { border-collapse: collapse; width: 100%; }
.matrix th, .matrix td { border: 1px solid var(--rule); padding: 0.5rem 0.7rem; vertical-align: top; text-align: left; }
.matrix thead th { background: var(--panel); }
.matrix .gap { color: var(--rule); }