/* The reference guide stays separate from the simulation workspace. */
#model-dialog.physics-guide {
  width: min(1000px, calc(100% - 32px));
  max-width: 1000px;
  height: min(900px, 90dvh);
  max-height: 90dvh;
  padding: 0;
  overflow: hidden;
  background: var(--surface);
  border-color: var(--line);
}
#model-dialog.physics-guide[open] { display: flex; flex-direction: column; }
body.guide-open { overflow: hidden; }
.guide-header { display: flex; justify-content: space-between; align-items: center; gap: 16px; padding: 24px 30px 20px; flex-shrink: 0; }
.guide-header .eyebrow { color: var(--muted); font-size: .7rem; }
.guide-header h2 { font-size: 1.75rem; margin: 6px 0 0; }
.guide-header .icon-button { flex-shrink: 0; font-size: 1.7rem; width: 44px; height: 44px; }
.guide-tabs { display: grid; grid-template-columns: 1.25fr .8fr 1.25fr; gap: 6px; padding: 0 30px 16px; border-bottom: 1px solid var(--line); flex-shrink: 0; }
.guide-tabs button { border: 1px solid var(--line); border-radius: 9px; background: var(--surface); color: var(--muted); padding: 12px 10px; font-size: .875rem; line-height: 1.4; min-width: 0; }
.guide-tabs button:hover { background: var(--surface-up); color: var(--text); }
.guide-tabs button[aria-selected="true"] { color: var(--orange); background: var(--orange-dark); border-color: var(--orange); font-weight: 600; }
.guide-body { overflow-y: auto; overscroll-behavior: contain; padding: 24px 30px 30px; min-height: 0; scrollbar-gutter: stable; }
.guide-body > [role="tabpanel"] { min-width: 0; }
#model-dialog .guide-intro { margin: 0 0 22px; max-width: 80ch; font-size: .95rem; }
.guide-card { border: 1px solid var(--line); border-radius: 12px; margin-bottom: 12px; background: var(--surface); }
.guide-card > summary { cursor: pointer; padding: 18px 20px; color: var(--text); font-size: 1rem; font-weight: 600; line-height: 1.5; border-radius: 12px; }
.guide-card > summary:hover { background: var(--surface-up); }
.guide-card > summary::marker { color: var(--orange); }
.guide-card-body { padding: 0 22px 20px; min-width: 0; }
#model-dialog .guide-card-body p { font-size: .9rem; margin: 12px 0; line-height: 1.75; }
#model-dialog .guide-card-body p:first-child { margin-top: 0; }
.guide-equation { max-width: 100%; min-width: 0; margin: 12px 0; padding: 10px 16px; background: var(--bg); border-radius: 8px; }
.guide-equation .katex-display { margin: 0; font-size: 1.05rem; }
.guide-definitions { margin: 16px 0; }
.guide-definitions > div { display: grid; grid-template-columns: 105px minmax(0, 1fr); gap: 18px; padding: 12px 0; border-bottom: 1px solid var(--line); }
.guide-definitions > div:last-child { border-bottom: 0; }
.guide-definitions dt { font-weight: 600; color: var(--text); }
.guide-definitions dd { margin: 0; color: var(--muted); font-size: .875rem; line-height: 1.75; min-width: 0; }
#model-dialog .guide-note { border-left: 2px solid var(--orange); padding: 8px 0 8px 14px; }
.guide-figure { margin: 18px 0; padding: 16px; border: 1px solid var(--line); border-radius: 10px; background: var(--map-bg); }
.guide-figure svg { display: block; width: 100%; min-width: 0; max-width: 620px; margin: auto; height: auto; }
.guide-figure svg text { fill: var(--text); font-family: var(--font); font-size: 15px; }
.guide-figure figcaption { max-width: 70ch; margin: 12px auto 0; color: var(--muted); font-size: .8rem; line-height: 1.65; }
.diagram-axis { fill: none; stroke: var(--map-axis); stroke-width: 1.3; }
.diagram-orbit { fill: none; stroke: var(--blue); stroke-width: 1.8; }
.diagram-dashed { fill: none; stroke: var(--map-axis); stroke-width: 1.3; stroke-dasharray: 5 5; }
.diagram-accent { fill: none; stroke: var(--orange); stroke-width: 2.5; }
.diagram-dimension { fill: none; stroke: var(--orange); stroke-width: 1.4; }
.diagram-sun { fill: var(--orange); }
.diagram-dot { fill: var(--text); }
.diagram-planet { fill: var(--blue); }
.diagram-arrival { fill: var(--surface); stroke: var(--orange); stroke-width: 2.5; }
.guide-energy-figure svg { max-width: 560px; }
.guide-energy-figure svg text, .guide-ellipse-figure svg text { font-size: 22px; }
.guide-ellipse-figure svg .ellipse-coordinate { font-size: 20px; }
.guide-ellipse-figure svg { max-width: 560px; }
.guide-energy-figure svg path, .guide-ellipse-figure svg path, .guide-ellipse-figure svg ellipse { vector-effect: non-scaling-stroke; }
.guide-diagram-key { display: flex; flex-wrap: wrap; gap: 12px 24px; justify-content: center; margin: 10px 0; font-size: .85rem; line-height: 1.5; }
.guide-diagram-key > div { display: flex; gap: 8px; align-items: baseline; }
.guide-diagram-key dt { color: var(--orange); font-weight: 600; }
.guide-diagram-key dd { color: var(--text); margin: 0; }
.guide-transfer-layout { display: grid; grid-template-columns: minmax(0, 1fr) 190px; align-items: center; gap: 20px; }
.guide-transfer-figure svg { max-width: 460px; min-width: 0; }
.guide-transfer-figure svg .transfer-symbol { font-size: 19px; }
.guide-transfer-figure svg .transfer-point-label { font-size: 22px; font-weight: 600; }
.guide-transfer-figure svg .transfer-burn-label { font-size: 17px; }
.guide-transfer-key { color: var(--muted); font-size: .85rem; line-height: 1.5; }
.guide-transfer-key dl { display: grid; gap: 16px; margin: 0 0 26px; }
.guide-transfer-key dl > div { display: grid; grid-template-columns: 32px minmax(0, 1fr); align-items: baseline; gap: 8px; }
.guide-transfer-key dt { font-weight: 600; color: var(--orange); }
.guide-transfer-key dt.transfer-earth { color: var(--blue); }
.guide-transfer-key dd { margin: 0; color: var(--text); }
.guide-orbit-key { display: flex; align-items: center; gap: 10px; margin: 10px 0; }
.guide-orbit-key > span { width: 24px; flex-shrink: 0; border-top: 2px solid var(--map-axis); }
.guide-orbit-key .orbit-key-transfer { border-color: var(--orange); border-top-width: 3px; }
.guide-orbit-key .orbit-key-earth { border-color: var(--blue); }
.guide-orbit-key .orbit-key-mars { border-top-style: dashed; }
@media (max-width: 800px) {
  .guide-transfer-layout { grid-template-columns: 1fr; gap: 8px; }
  .guide-transfer-key { display: grid; grid-template-columns: 1fr 1fr; gap: 8px 12px; padding: 8px; font-size: .8rem; }
  .guide-transfer-key dl { grid-column: 1 / -1; grid-template-columns: 1fr; gap: 10px; margin-bottom: 12px; }
  .guide-orbit-key { margin: 0; }
}
.guide-sources { display: flex; gap: 12px 20px; flex-wrap: wrap; padding-top: 16px; margin-top: 20px; border-top: 1px solid var(--line); font-size: .8rem; }
.guide-sources > span { width: 100%; color: var(--muted); }
.guide-sources a { color: var(--orange); text-decoration: underline; text-underline-offset: 3px; }
.guide-model-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; margin-bottom: 20px; }
.guide-model-card { min-width: 0; padding: 20px; background: var(--bg); border: 1px solid var(--line); border-radius: 12px; }
#model-dialog .guide-model-card h3 { font-size: 1rem; margin: 0; }
#model-dialog .guide-model-card p { margin: 10px 0 0; font-size: .875rem; line-height: 1.75; }
#model-dialog .guide-card-body ul { color: var(--muted); font-size: .9rem; line-height: 1.75; margin: 0; }
.guide-table-wrap { overflow-x: auto; }
.guide-table { width: 100%; border-collapse: collapse; font-size: .875rem; }
.guide-table caption { text-align: left; font-weight: 600; padding: 12px 0; }
.guide-table th, .guide-table td { padding: 10px 12px; border-bottom: 1px solid var(--line); text-align: left; }
.guide-table th { background: var(--bg); color: var(--text); }
.guide-table td { color: var(--muted); font-variant-numeric: tabular-nums; }
.guide-table td:last-child, .guide-table th:last-child { text-align: right; }
.guide-facts { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; margin: 16px 0; }
.guide-fact { min-width: 0; background: var(--bg); padding: 10px 12px; border-radius: 8px; }
.guide-fact > span { display: block; color: var(--muted); font-size: .8rem; }
.guide-fact > strong { display: block; margin-top: 4px; font-size: .95rem; font-weight: 500; }
#model-dialog #guide-example-calculations h3 { font-size: .95rem; margin: 24px 0 12px; }
@media (max-width: 600px) {
  #model-dialog.physics-guide { width: calc(100% - 16px); height: 94dvh; max-height: 94dvh; border-radius: 14px; }
  .guide-header { padding: 16px 16px 14px; }
  .guide-header h2 { font-size: 1.4rem; }
  .guide-tabs { gap: 5px; padding: 0 12px 12px; }
  .guide-tabs button { font-size: .75rem; padding: 10px 5px; }
  .guide-body { padding: 18px 12px 24px; scrollbar-gutter: auto; }
  .guide-card > summary { font-size: .9rem; padding: 15px 12px; }
  .guide-card-body { padding: 0 12px 16px; }
  .guide-definitions > div { grid-template-columns: 65px minmax(0, 1fr); gap: 10px; }
  .guide-equation { padding: 10px; }
  .guide-equation .katex-display { font-size: .95rem; }
  .guide-model-grid { grid-template-columns: 1fr; }
  .guide-figure { padding: 8px; }
  .guide-ellipse-figure svg text { font-size: 26px; }
  .guide-ellipse-figure svg .ellipse-coordinate { font-size: 24px; }
  .guide-diagram-key { display: grid; justify-content: start; gap: 8px; padding: 8px; }
  .guide-facts { grid-template-columns: 1fr; }
}