/* Lecture design system.
   One layer for every lecture page: typography, section hierarchy, concept and worked-example
   cards, callouts, QA artifact tables, knowledge checks, and figure frames.
   Loaded after lecture.css, lesson.css and theme.css. Every rule is scoped under .lecture-block so
   other pages are not affected. Colours come from the theme tokens, so light and dark modes both work.

   Components (class names come from js/markdown.js and js/app.js):
   - .l1-hero          lecture title block
   - .l1-section       numbered section (header .num + h2)
   - .concept          subsection card (h3 + paragraphs)
   - .lbl              inline label, e.g. "Simple explanation"
   - .callout          note / important / misconception callout
   - .step             worked-example step (.badge + h3)
   - .table-card       responsive table wrapper; .grid-table with data-label stacks on phones
   - .grid-table--kv   key/value table (first header "Field")
   - .mistake          common mistake card
   - .takeaways        key takeaway list
   - .kc               knowledge-check question
   - .key              answer key (details)
   - .visual           figure with header, canvas and caption
*/

/* Typography and rhythm */
.lecture-block {
  font-size: 17px;
  line-height: 1.7;
  color: var(--text);
  min-width: 0;
  overflow-wrap: break-word;
}
.lecture-block .lecture-body {
  min-width: 0;
}
.lecture-block .lecture-body > p,
.lecture-block .l1-section > p,
.lecture-block .concept > p,
.lecture-block .step > div > p {
  margin: 0 0 14px;
  max-width: 72ch;
}
.lecture-block .lecture-body p,
.lecture-block .lecture-body li {
  overflow-wrap: anywhere;
}
.lecture-block .l1-section > p + p {
  margin-top: -4px;
}
.lecture-block .lecture-body ol,
.lecture-block .lecture-body ul {
  margin: 4px 0 18px;
  padding-left: 1.35em;
  max-width: 72ch;
}
.lecture-block .lecture-body li {
  margin: 6px 0;
}
.lecture-block .lecture-body li::marker {
  color: var(--accent);
  font-weight: 700;
}
.lecture-block .lecture-body strong {
  color: var(--heading);
}
.lecture-block .lecture-body code {
  font-size: 0.92em;
  padding: 1px 6px;
  border-radius: 6px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--indigo);
}
[data-theme="dark"] .lecture-block .lecture-body code {
  color: var(--heading);
}

/* Section hierarchy: each numbered section is a clear chapter */
.lecture-block .l1-section {
  margin: 56px 0 0;
  padding-top: 32px;
  border-top: 1px solid var(--border);
}
.lecture-block .l1-section > header {
  display: flex;
  align-items: center;
  gap: 14px;
  margin: 0 0 20px;
}
.lecture-block .l1-section > header .num {
  flex: 0 0 auto;
  width: 40px;
  height: 40px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  background: var(--brand-gradient);
  color: var(--accent-text);
  font-weight: 800;
  font-size: 16px;
  box-shadow: var(--shadow);
}
.lecture-block .l1-section > header h2 {
  margin: 0;
  font-size: clamp(1.4rem, 1.2rem + 0.8vw, 1.75rem);
  line-height: 1.25;
  letter-spacing: -0.015em;
  color: var(--heading);
}

/* Subsections: concept cards */
.lecture-block .concept {
  margin: 22px 0;
  padding: 20px 22px 8px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
}
.lecture-block .concept > h3 {
  margin: 0 0 12px;
  padding-left: 12px;
  border-left: 3px solid var(--accent);
  font-size: 1.12rem;
  line-height: 1.35;
  color: var(--heading);
}
.lecture-block .lbl {
  display: inline-block;
  margin-right: 6px;
  padding: 2px 9px;
  border-radius: 999px;
  background: var(--brand-soft);
  color: var(--accent);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  vertical-align: 1px;
}
.lecture-block .concept > p:has(> .lbl),
.lecture-block .step p:has(> .lbl) {
  padding-left: 0;
}

/* Callouts: note, important point, common misunderstanding */
.lecture-block .callout {
  display: grid;
  gap: 4px;
  margin: 18px 0;
  padding: 14px 16px 14px 18px;
  border: 1px solid var(--border);
  border-left: 4px solid var(--info);
  border-radius: 14px;
  background: var(--info-bg);
  max-width: 72ch;
}
.lecture-block .callout--important {
  border-left-color: var(--warn);
  background: var(--warn-bg);
}
.lecture-block .callout--misconception {
  border-left-color: var(--bad);
  background: var(--bad-bg);
}
.lecture-block .callout__label {
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--heading);
}
.lecture-block .callout__text {
  margin: 0;
}

/* Worked example: numbered step cards */
.lecture-block .step {
  display: block;
  position: relative;
  margin: 22px 0;
  padding: 18px 20px 18px 66px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
}
.lecture-block .step > .badge {
  position: absolute;
  left: 18px;
  top: 18px;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: var(--brand-gradient);
  color: var(--accent-text);
  font-size: 14px;
  font-weight: 800;
}
.lecture-block .step h3 {
  margin: 4px 0 10px;
  font-size: 1.05rem;
  line-height: 1.35;
  color: var(--heading);
}

/* Artifact tables: responsive, with a stacked layout on phones */
.lecture-block .table-card {
  margin: 14px 0 26px;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: var(--surface);
  box-shadow: var(--shadow);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}
.lecture-block .grid-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  font-size: 15px;
  line-height: 1.5;
}
.lecture-block .grid-table th {
  padding: 11px 14px;
  background: var(--surface-2);
  border-bottom: 1px solid var(--border);
  color: var(--heading);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.05em;
  text-align: left;
  text-transform: uppercase;
  white-space: nowrap;
}
.lecture-block .grid-table td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
  color: var(--text);
  min-width: 8rem;
}
.lecture-block .grid-table tbody tr:last-child td {
  border-bottom: 0;
}
.lecture-block .grid-table tbody tr:hover td {
  background: var(--surface-2);
}
.lecture-block .grid-table td.id {
  white-space: nowrap;
  font-family: ui-monospace, Menlo, Consolas, monospace;
  font-size: 13.5px;
  font-weight: 700;
  color: var(--accent);
}
.lecture-block .grid-table--kv td:first-child {
  width: 30%;
  font-weight: 700;
  color: var(--heading);
  background: var(--surface-2);
}
.lecture-block .caption {
  margin: 22px 0 6px;
  font-size: 15px;
  font-weight: 700;
  color: var(--heading);
}

/* Common mistakes */
.lecture-block .mistake {
  margin: 22px 0;
  padding: 18px 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-top: 4px solid var(--bad);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
}
.lecture-block .mistake h3 {
  margin: 0 0 8px;
  font-size: 1.05rem;
  line-height: 1.35;
  color: var(--heading);
}
.lecture-block .mistake .k {
  display: block;
  margin-top: 6px;
  color: var(--muted);
  max-width: 72ch;
}
.lecture-block .mistake .k b {
  color: var(--heading);
}

/* Learning objectives: numbered cards, badge on the left */
.lecture-block ol.objectives {
  display: grid;
  gap: 10px;
  margin: 4px 0 22px;
  padding: 0;
  list-style: none;
  max-width: none;
  counter-reset: objective;
}
.lecture-block ol.objectives > li {
  counter-increment: objective;
  position: relative;
  margin: 0;
  padding: 14px 16px 14px 64px;
  min-height: 56px;
  display: flex;
  align-items: center;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  box-shadow: var(--shadow);
  line-height: 1.5;
}
.lecture-block ol.objectives > li::before {
  content: counter(objective);
  position: absolute;
  left: 16px;
  top: 50%;
  transform: translateY(-50%);
  width: 32px;
  height: 32px;
  border-radius: 10px;
  display: grid;
  place-items: center;
  background: var(--accent);
  color: #ffffff;
  font-size: 14px;
  font-weight: 800;
}

/* Best practices heading, takeaways, numbered lists */
.lecture-block .practice-title {
  margin: 28px 0 10px;
  font-size: 1.1rem;
  color: var(--heading);
}
.lecture-block .takeaways {
  list-style: none;
  padding: 0;
  margin: 8px 0 18px;
  counter-reset: takeaway;
  max-width: none;
}
.lecture-block .takeaways > li {
  counter-increment: takeaway;
  display: grid;
  grid-template-columns: 30px 1fr;
  gap: 12px;
  align-items: start;
  margin: 0 0 10px;
  padding: 12px 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  /* Overrides the absolute-position card rules in lecture.css, which would
     otherwise push the text into the 30px number column. */
  position: relative;
  left: auto;
  top: auto;
  font-size: 15.5px;
  line-height: 1.6;
  box-shadow: none;
  transform: none;
}
.lecture-block .takeaways > li::before {
  content: counter(takeaway);
  position: static;
  width: 30px;
  height: 30px;
  border-radius: 9px;
  display: grid;
  place-items: center;
  background: var(--brand-soft);
  color: var(--accent);
  font-weight: 800;
  font-size: 14px;
}
.lecture-block .takeaways > li::marker {
  content: "";
}

/* Knowledge check */
.lecture-block .kc {
  margin: 18px 0;
  padding: 18px 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 4px solid var(--accent);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
}
.lecture-block .kc .q .n {
  display: inline-block;
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent);
}
.lecture-block .kc .q p {
  margin: 6px 0 0;
  font-weight: 600;
  color: var(--heading);
  max-width: 72ch;
}
.lecture-block .key {
  margin: 28px 0 0;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
}
.lecture-block .key > summary {
  cursor: pointer;
  padding: 14px 18px;
  font-weight: 800;
  color: var(--heading);
  list-style-position: inside;
}
.lecture-block .key > ol {
  margin: 0;
  padding: 0 18px 16px 42px;
}
.lecture-block .key > ol > li {
  margin: 10px 0;
  max-width: 72ch;
}

/* Figures */
.lecture-block .visual {
  margin: 26px 0;
  min-width: 0;
}
.lecture-block .visual-frame {
  overflow: hidden;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: var(--surface);
  box-shadow: var(--shadow);
}
.lecture-block .visual-header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 12px;
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
  background: var(--surface-2);
}
.lecture-block .visual-badge {
  padding: 3px 10px;
  border-radius: 999px;
  background: var(--brand-soft);
  color: var(--accent);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.lecture-block .visual-kicker {
  font-size: 12px;
  color: var(--muted);
}
.lecture-block .visual-title {
  font-weight: 700;
  color: var(--heading);
}
.lecture-block .visual-canvas {
  padding: 10px;
  overflow-x: auto;
}
.lecture-block .visual-canvas svg {
  display: block;
  width: 100%;
  height: auto;
}
.lecture-block .visual-caption {
  margin: 12px 4px 0;
  max-width: 72ch;
}
.lecture-block .visual-caption__title {
  display: block;
  font-size: 15px;
  color: var(--heading);
}
.lecture-block .visual-caption__text {
  margin: 4px 0 0;
  font-size: 15px;
  color: var(--muted);
}

/* Phones: tighter cards, stacked tables, horizontally scrollable figures */
@media (max-width: 680px) {
  .lecture-block {
    font-size: 16px;
  }
  .lecture-block .l1-section {
    margin-top: 40px;
    padding-top: 24px;
  }
  .lecture-block .l1-section > header .num {
    width: 34px;
    height: 34px;
    font-size: 14px;
  }
  .lecture-block .concept {
    padding: 16px 16px 6px;
  }
  .lecture-block .step {
    padding: 16px 16px 16px 58px;
  }
  .lecture-block .step > .badge {
    left: 14px;
    top: 16px;
    width: 30px;
    height: 30px;
  }
  .lecture-block .table-card {
    overflow-x: auto;
    border: 0;
    background: transparent;
    box-shadow: none;
  }
  .lecture-block .grid-table thead {
    display: none;
  }
  .lecture-block .grid-table,
  .lecture-block .grid-table * {
    box-sizing: border-box;
  }
  .lecture-block .grid-table,
  .lecture-block .grid-table tbody,
  .lecture-block .grid-table tr,
  .lecture-block .grid-table td {
    display: block;
    width: 100%;
  }
  .lecture-block .grid-table tbody tr {
    margin-bottom: 12px;
    padding: 6px 14px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow);
  }
  .lecture-block .grid-table td {
    min-width: 0;
    overflow-wrap: anywhere;
    white-space: normal;
    padding: 8px 0;
    border-bottom: 1px solid var(--border);
  }
  .lecture-block .grid-table tbody tr td:last-child {
    border-bottom: 0;
  }
  .lecture-block .grid-table td[data-label]::before {
    content: attr(data-label);
    display: block;
    margin-bottom: 2px;
    font-size: 11px;
    font-weight: 800;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--muted);
  }
  .lecture-block .grid-table--kv td:first-child {
    width: 100%;
    background: none;
  }
  .lecture-block .visual-canvas svg {
    min-width: 470px;
  }
  .lecture-block .takeaways > li {
    padding: 10px 12px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .lecture-block * {
    transition: none !important;
    animation: none !important;
  }
}

/* Wide figure tables (decision tables) scroll inside their own frame instead of widening the page. */
.lecture-block .visual,
.lecture-block .visual-frame,
.lecture-block .visual-canvas,
.lecture-block .decision-table-wrap,
.lecture-block .decision-table-wrap__scroll {
  max-width: 100%;
  min-width: 0;
}
.lecture-block .decision-table-wrap__scroll {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}