/* ====================================================================
   JMaths Explainer Styles — jm-lesson
   Designed for deep-dive concept explainers in AI HL and Year 10
   ==================================================================== */

.jm-lesson {
  --jm-teal: #127970;
  --jm-teal-deep: #0C625B;
  --jm-teal-light: #EBF7F5;
  --jm-orange: #ED8B00;
  --jm-orange-deep: #C77300;
  --jm-orange-pale: #FDF3E6;
  --jm-ink: var(--color-text);
  --jm-line: var(--color-border);
  --jm-muted: var(--color-text-muted);
  --jm-card-bg: #FFFFFF;

  max-width: 820px;
  margin: 0 auto;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  color: var(--jm-ink);
  line-height: 1.65;
  font-size: 1.05rem;
}

.jm-lesson-shell {
  padding: 1.5rem 1rem 4rem;
}

.jm-lesson .jm-kicker {
  font-size: 0.85rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--jm-teal);
  font-weight: 700;
  margin: 0 0 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.jm-lesson h1 {
  font-family: 'Bricolage Grotesque', system-ui, sans-serif;
  font-size: 2.25rem;
  font-weight: 800;
  line-height: 1.2;
  color: var(--jmaths-gray-900);
  margin: 0 0 1.25rem;
  letter-spacing: -0.02em;
}

.jm-lesson .jm-lead {
  font-size: 1.2rem;
  color: var(--jmaths-gray-700);
  line-height: 1.6;
  margin-bottom: 1.75rem;
  font-weight: 400;
}

.jm-lesson .jm-key {
  border-left: 5px solid var(--jm-teal);
  padding: 1.1rem 1.3rem;
  background: var(--jm-teal-light);
  border-radius: 0 10px 10px 0;
  margin: 1.5rem 0 2rem;
  font-size: 1.1rem;
  box-shadow: 0 2px 6px rgba(18, 121, 112, 0.06);
}

.jm-lesson .jm-key strong {
  color: var(--jm-teal-deep);
}

.jm-lesson .jm-card {
  border: 1px solid var(--jm-line);
  border-radius: 12px;
  padding: 1.5rem 1.75rem;
  margin: 1.75rem 0;
  background: var(--jm-card-bg);
  box-shadow: 0 4px 12px rgba(15, 23, 42, 0.03);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.jm-lesson .jm-card h2 {
  font-family: 'Bricolage Grotesque', system-ui, sans-serif;
  font-size: 1.45rem;
  font-weight: 700;
  color: var(--jmaths-gray-900);
  margin: 0 0 1rem;
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.jm-lesson .jm-badge {
  display: inline-block;
  padding: 0.2rem 0.55rem;
  border-radius: 6px;
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.jm-lesson .jm-badge-teal {
  background: var(--jm-teal-light);
  color: var(--jm-teal-deep);
}

.jm-lesson .jm-badge-orange {
  background: var(--jm-orange-pale);
  color: var(--jm-orange-deep);
}

.jm-lesson figure {
  margin: 1.5rem 0;
  text-align: center;
}

.jm-lesson figure svg {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  border: 1px solid var(--jm-line);
  background: #FAFCFC;
}

.jm-lesson figcaption {
  font-size: 0.9rem;
  color: var(--jm-muted);
  margin-top: 0.6rem;
}

.jm-lesson ul, .jm-lesson ol {
  padding-left: 1.4rem;
  margin: 0.75rem 0 1.25rem;
}

.jm-lesson li {
  margin-bottom: 0.5rem;
}

.jm-lesson .jm-slide-box {
  background: linear-gradient(135deg, var(--color-bg-subtle) 0%, var(--jm-teal-light) 100%);
  border: 1px solid var(--jmaths-gray-300);
  border-radius: 12px;
  padding: 1.25rem 1.5rem;
  margin: 2rem 0;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.jm-lesson .jm-slide-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.jm-lesson .jm-slide-title {
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--jmaths-gray-900);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.jm-lesson .jm-slide-actions {
  display: flex;
  gap: 0.5rem;
}

.jm-lesson .jm-btn-download {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.45rem 0.85rem;
  border-radius: 6px;
  font-size: 0.85rem;
  font-weight: 600;
  text-decoration: none;
  background: #FFFFFF;
  color: var(--jm-teal-deep);
  border: 1px solid var(--jm-line);
  transition: all 0.15s ease;
}

.jm-lesson .jm-btn-download:hover {
  background: var(--jm-teal);
  color: #FFFFFF;
  border-color: var(--jm-teal);
}

.jm-lesson .jm-slide-preview {
  width: 100%;
  border-radius: 8px;
  border: 1px solid var(--jmaths-gray-300);
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.05);
}

.jm-lesson table.jm-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.25rem 0 2rem;
  font-size: 0.95rem;
  background: #FFFFFF;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--jm-line);
}

.jm-lesson table.jm-table th,
.jm-lesson table.jm-table td {
  border-bottom: 1px solid var(--jm-line);
  padding: 0.75rem 1rem;
  text-align: left;
  vertical-align: top;
}

.jm-lesson table.jm-table th {
  background: var(--color-bg-subtle);
  color: var(--jm-teal-deep);
  font-weight: 700;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.jm-lesson table.jm-table tr:last-child td {
  border-bottom: none;
}

.jm-lesson .jm-warn {
  border-left: 5px solid var(--jm-orange);
  padding: 1rem 1.25rem;
  background: var(--jm-orange-pale);
  border-radius: 0 8px 8px 0;
  margin: 1.5rem 0;
  color: #78350F;
}

.jm-lesson details.jm-accordion {
  border: 1px solid var(--jm-line);
  border-radius: 10px;
  padding: 0.9rem 1.2rem;
  margin: 0.85rem 0;
  background: #FFFFFF;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.02);
  transition: border-color 0.15s ease;
}

.jm-lesson details.jm-accordion[open] {
  border-color: var(--jm-teal);
}

.jm-lesson details.jm-accordion summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--jmaths-gray-900);
  list-style-type: none;
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1.25rem;
}

.jm-lesson details.jm-accordion summary .jm-summary-title {
  flex: 1;
  line-height: 1.5;
}

.jm-lesson details.jm-accordion summary::-webkit-details-marker {
  display: none;
}

.jm-lesson details.jm-accordion summary::after {
  content: "\f078";
  font-family: "Font Awesome 6 Free";
  font-weight: 900;
  font-size: 0.8rem;
  color: var(--jm-muted);
  transition: transform 0.2s ease;
  margin-top: 0.3rem;
  flex-shrink: 0;
}

.jm-lesson details.jm-accordion[open] summary::after {
  transform: rotate(180deg);
  color: var(--jm-teal);
}

.jm-lesson details.jm-accordion[open] summary {
  margin-bottom: 0.85rem;
  padding-bottom: 0.6rem;
  border-bottom: 1px dashed var(--jm-line);
}

.jm-lesson .jm-answer-body {
  color: var(--jmaths-gray-700);
}

.jm-lesson .jm-footer-nav {
  margin-top: 3.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--jm-line);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
}

.jm-lesson .jm-source {
  font-size: 0.85rem;
  color: var(--jm-muted);
}

@media (max-width: 600px) {
  .jm-lesson h1 {
    font-size: 1.75rem;
  }
  .jm-lesson .jm-card {
    padding: 1.15rem 1rem;
  }
  .jm-lesson table.jm-table {
    display: block;
    overflow-x: auto;
  }
}

/* In-page contents, side notes and figure sizing (used by section pages such as
   "Where are eigenvectors used?"). */
.jm-lesson figure > svg {
  width: 100%;
  max-width: 440px;
}

.jm-lesson .jm-toc {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 1rem;
  font-size: 0.9rem;
  margin: 0 0 1.75rem;
}

.jm-lesson .jm-toc a {
  color: var(--jm-teal-deep);
  text-decoration: none;
  border-bottom: 1px solid var(--jm-line);
}

.jm-lesson .jm-toc a:hover {
  border-bottom-color: var(--jm-teal);
}

.jm-lesson .jm-note {
  font-size: 0.95rem;
  color: var(--jm-muted);
}

.jm-lesson .jm-slide-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: 0.6rem;
}

.jm-lesson .jm-slide-grid img {
  width: 100%;
  height: auto;
  border-radius: 6px;
  border: 1px solid var(--jm-line);
}

.jm-lesson section[id] {
  scroll-margin-top: 5rem;
}

.jm-lesson .jm-table-wrap {
  overflow-x: auto;
}

.jm-lesson .jm-table-wrap table.jm-table {
  min-width: 28rem;
}