/*
 * Lesson stylesheet.
 *
 * Source of truth for all lesson visual styling. Lessons under
 * learning/agents-sdk/lessons/ load this from /assets/lesson.css. Do not
 * inline any of these rules in lesson HTML; if you need a one-off tweak,
 * either add it here as a documented variant or scope it via a class.
 *
 * Palette uses CSS variables on :root. Override per-lesson by setting
 * variables in a small inline <style> block in the lesson header (e.g. for
 * the per-work-item color identity feature, when implemented).
 */

:root {
  --bg: #0f1115;
  --panel: #171a21;
  --panel-2: #1e222b;
  --border: #2a2f3a;
  --text: #e6e8eb;
  --muted: #9aa3af;
  --accent: #f6821f;
  --ok: #4ade80;
  --warn: #fbbf24;
  --err: #f87171;
  --code-bg: #0b0d11;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family:
    -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto,
    Helvetica, Arial, sans-serif;
  line-height: 1.55;
  -webkit-text-size-adjust: 100%;
  /*
   * NOTE: do not set overflow-x: hidden here. Setting any overflow other
   * than visible on an ancestor breaks position: sticky on the nav (the
   * sticky element sticks to that ancestor instead of the viewport).
   * Horizontal blowout is handled per-element on .table-wrap and .diagram.
   */
}

.layout {
  display: grid;
  grid-template-columns: 260px minmax(0, 1fr);
  max-width: 1280px;
  margin: 0 auto;
  min-height: 100vh;
}

/*
 * Nav uses --accent as its background. Lesson HTML sets --accent per work
 * item via an inline <style>. Text colors flip to dark for legibility on
 * the colored background. Hover uses a subtle dark tint that reads against
 * the accent across hues.
 */
nav {
  position: sticky;
  top: 0;
  align-self: start;
  padding: 24px 16px;
  border-right: 1px solid rgba(15, 17, 21, 0.2);
  height: 100vh;
  overflow-y: auto;
  background: var(--accent);
  color: #0f1115;
}
nav > details > summary { display: none; }
nav > details > h2,
nav > details > ol { display: block; }
nav h2 {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: rgba(15, 17, 21, 0.65);
  margin: 0 0 12px;
}
nav ol { margin: 0; padding: 0 0 0 18px; }
nav ol li { margin: 6px 0; }
nav a {
  color: #0f1115;
  text-decoration: none;
  font-size: 14px;
}
nav a:hover {
  color: #0f1115;
  text-decoration: underline;
}

main { padding: 32px 40px 80px; max-width: 880px; min-width: 0; }
h1 { font-size: 28px; margin: 0 0 8px; }
h2 {
  font-size: 22px;
  margin: 40px 0 12px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 6px;
}
h3 { font-size: 17px; margin: 24px 0 8px; color: var(--accent); }
p, li { font-size: 15px; }

/*
 * Inline code uses a subtle panel; block code uses the darker code-bg.
 * Prism syntax highlighting is applied on top via /assets/prism.css and
 * /assets/lesson.js. Lesson authors should set class="language-<lang>" on
 * each <code> inside a <pre>. Supported languages: typescript, javascript,
 * tsx, jsx, json, bash, sql, html, css. If you need a language not in that
 * list, add it to the Prism component list in lesson.js.
 */
code {
  background: var(--code-bg);
  padding: 1px 6px;
  border-radius: 4px;
  font-size: 13px;
  font-family:
    "SF Mono", Menlo, Monaco, Consolas, "Liberation Mono", monospace;
  color: var(--text);
  border: 1px solid var(--border);
}
pre {
  background: var(--code-bg);
  padding: 14px 16px;
  border-radius: 6px;
  overflow-x: auto;
  border: 1px solid var(--border);
  font-size: 13px;
  line-height: 1.5;
}
pre code { background: transparent; border: 0; padding: 0; }

/* Prism Tomorrow theme overrides to integrate with the lesson palette. */
pre[class*="language-"],
code[class*="language-"] {
  background: var(--code-bg);
  color: var(--text);
  text-shadow: none;
  font-family:
    "SF Mono", Menlo, Monaco, Consolas, "Liberation Mono", monospace;
}

.callout {
  padding: 12px 16px;
  border-left: 3px solid var(--accent);
  background: var(--panel-2);
  border-radius: 0 6px 6px 0;
  margin: 16px 0;
}
.callout.warn { border-left-color: var(--warn); }
.callout.err { border-left-color: var(--err); }
.callout.ok { border-left-color: var(--ok); }
.callout h4 {
  margin: 0 0 6px;
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
}

.diagram {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 16px;
  margin: 16px 0;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}
.diagram svg { max-width: 100%; height: auto; display: block; }
.diagram .edgeLabel,
.diagram .edgeLabel p,
.diagram .edgeLabel span,
.diagram .edgeLabel .label text,
.diagram .edgeLabel foreignObject div {
  color: var(--text) !important;
  fill: var(--text) !important;
}
.diagram .edgeLabel .label rect,
.diagram .edgeLabel rect {
  fill: var(--panel) !important;
  opacity: 1 !important;
}
.diagram .edgeLabel foreignObject { background: transparent !important; }
.diagram .nodeLabel,
.diagram .cluster-label {
  fill: var(--text) !important;
  color: var(--text) !important;
}

.table-wrap {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  margin: 16px 0;
  border: 1px solid var(--border);
  border-radius: 6px;
}
.table-wrap table { margin: 0; border: 0; }
table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  font-size: 14px;
}
th, td {
  text-align: left;
  padding: 8px 12px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}
th {
  color: var(--muted);
  font-weight: 600;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.pill {
  display: inline-block;
  padding: 1px 8px;
  border-radius: 999px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.pill.ok { background: rgba(74, 222, 128, 0.16); color: var(--ok); }
.pill.warn { background: rgba(251, 191, 36, 0.16); color: var(--warn); }
.pill.err { background: rgba(248, 113, 113, 0.16); color: var(--err); }
.pill.muted { background: rgba(154, 163, 174, 0.16); color: var(--muted); }

.ref {
  color: var(--muted);
  font-size: 12px;
  font-family:
    "SF Mono", Menlo, Monaco, Consolas, "Liberation Mono", monospace;
}
.ref a { color: var(--accent); text-decoration: none; }

.check {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 16px 20px;
  margin: 16px 0;
}
.check h4 {
  margin: 0 0 8px;
  color: var(--accent);
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.check details { margin-top: 8px; }
.check summary { cursor: pointer; color: var(--muted); font-size: 13px; }
.check details[open] summary { color: var(--text); }

footer {
  margin-top: 60px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 13px;
}

@media (max-width: 820px) {
  .layout { display: block; max-width: 100%; }
  nav {
    position: static;
    height: auto;
    border-right: 0;
    border-bottom: 1px solid rgba(15, 17, 21, 0.2);
    padding: 12px 16px;
  }
  nav > details { display: block; }
  nav > details > summary {
    display: block;
    cursor: pointer;
    padding: 6px 0;
    color: #0f1115;
    font-size: 14px;
    font-weight: 600;
    list-style: none;
  }
  nav > details > summary::-webkit-details-marker { display: none; }
  nav > details > summary::before {
    content: "☰  ";
    color: rgba(15, 17, 21, 0.6);
    margin-right: 4px;
  }
  nav > details[open] > summary::before { content: "✕  "; }
  nav h2 { margin-top: 12px; }
  nav h2:first-of-type { margin-top: 8px; }
  main { padding: 20px 16px 60px; max-width: 100%; }
  h1 { font-size: 24px; }
  h2 { font-size: 19px; margin-top: 32px; }
  h3 { font-size: 16px; }
  p, li { font-size: 15px; }
  pre { padding: 12px; font-size: 12px; border-radius: 6px; }
  .diagram {
    padding: 10px;
    margin-left: -16px;
    margin-right: -16px;
    border-radius: 0;
    border-left: 0;
    border-right: 0;
  }
  .table-wrap {
    margin-left: -16px;
    margin-right: -16px;
    border-radius: 0;
    border-left: 0;
    border-right: 0;
  }
  table { font-size: 13px; }
  th, td { padding: 8px 10px; }
  .callout { padding: 10px 14px; }
  .check { padding: 14px 16px; }
}