/* VLA learning roadmap */
.vla { max-width: 920px; }
.vla-stats { list-style: none; display: flex; flex-wrap: wrap; gap: 8px 22px; margin: 14px 0 0; padding: 0; color: var(--ink-2); font-size: 15px; }
.vla-stats strong { color: var(--ink); font-size: 20px; font-weight: 800; margin-right: 3px; }
.vla-note { margin: 16px 0 0; padding: 10px 14px; background: var(--orange-2); border-left: 4px solid var(--orange); border-radius: 6px; color: var(--ink); font-size: 14.5px; }
.vla-journey { list-style: none; display: flex; flex-wrap: wrap; gap: 8px; margin: 22px 0 6px; padding: 0; counter-reset: stage; }
.vla-journey li { counter-increment: stage; flex: 1 1 140px; display: flex; flex-direction: column; padding: 10px 14px; background: var(--cobalt-2); border-radius: 8px; position: relative; }
.vla-journey li:last-child { background: var(--orange-2); }
.vla-journey strong { font-size: 15px; }
.vla-journey span { font-size: 12.5px; color: var(--ink-2); }
.vla-bar { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 10px; margin-top: 30px; }
.vla-h2 { font-size: 22px; font-weight: 800; font-stretch: 85%; margin: 0; }
.vla-actions { display: flex; gap: 8px; }
.vla-actions[hidden] { display: none; }
.vla-hint { color: var(--ink-2); margin: 4px 0 18px; font-size: 14.5px; }
.vla-timeline { list-style: none; margin: 0; padding: 0 0 0 22px; position: relative; }
.vla-timeline::before { content: ''; position: absolute; left: 21px; top: 8px; bottom: 8px; width: 2px; background: var(--rule); }
.vla-phase { position: relative; margin: 0 0 14px; padding-left: 34px; }
.vla-node { position: absolute; left: -2px; top: 14px; width: 28px; height: 28px; border-radius: 50%; background: var(--cobalt); color: #fff; font: 800 13px/28px var(--font); text-align: center; box-shadow: 0 0 0 4px var(--paper); }
:root[data-theme="dark"] .vla-node { color: #0F1729; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .vla-node { color: #0F1729; } }
.vla-phase:last-child .vla-node { background: var(--orange); }
.vla-phase details { background: var(--panel); border: 1px solid var(--rule); border-radius: 10px; }
.vla-phase details[open] { border-color: var(--cobalt); }
.vla-phase summary { list-style: none; cursor: pointer; display: grid; gap: 6px; padding: 14px 44px 14px 16px; position: relative; border-radius: 10px; }
.vla-phase summary::-webkit-details-marker { display: none; }
.vla-phase summary::after { content: ''; position: absolute; right: 18px; top: 22px; width: 8px; height: 8px; border-right: 2px solid var(--ink-3); border-bottom: 2px solid var(--ink-3); transform: rotate(45deg); transition: transform .15s; }
.vla-phase details[open] > summary::after { transform: rotate(-135deg); top: 26px; }
.vla-phase summary:hover { background: var(--grid); }
.vla-phase-head { display: flex; flex-direction: column; gap: 1px; }
.vla-phase-label { font-size: 12px; font-weight: 800; letter-spacing: .08em; text-transform: uppercase; color: var(--cobalt); }
.vla-phase-title { font-size: 19px; font-weight: 800; line-height: 1.25; }
.vla-phase-sum { color: var(--ink-2); font-size: 14.5px; }
.vla-chips { list-style: none; display: flex; flex-wrap: wrap; gap: 6px; margin: 2px 0 0; padding: 0; }
.vla-phase details[open] .vla-chips { display: none; }
.vla-chips li { font-size: 12.5px; padding: 2px 9px; border: 1px solid var(--rule); border-radius: 999px; color: var(--ink-2); background: var(--paper); }
.vla-phase-meta { font-size: 12.5px; color: var(--ink-3); }
.vla-topics { list-style: none; margin: 0; padding: 4px 16px 14px; border-top: 1px solid var(--rule); }
.vla-topic { display: grid; grid-template-columns: 38px minmax(0, 1fr) auto; gap: 4px 12px; align-items: start; padding: 12px 0; border-bottom: 1px solid var(--grid); }
.vla-topic:last-child { border-bottom: 0; padding-bottom: 0; }
.vla-topic:target { background: var(--cobalt-2); border-radius: 6px; }
.vla-topic-no { font: 700 12px/1.9 var(--mono); color: var(--ink-3); }
.vla-topic h4 { margin: 0; font-size: 16px; line-height: 1.35; }
.vla-topic p { margin: 2px 0 0; color: var(--ink-2); font-size: 14px; }
.vla-lesson { font-size: 12.5px; font-weight: 600; color: var(--ink-3); border: 1px dashed var(--rule); border-radius: 999px; padding: 2px 10px; white-space: nowrap; }
.vla-lesson.is-live { color: var(--cobalt); border: 1px solid var(--cobalt); text-decoration: none; }
.vla-lesson.is-live:hover { background: var(--cobalt-2); }
.vla-foot { margin: 22px 0 0; }
@media (max-width: 620px) {
  .vla-timeline { padding-left: 14px; }
  .vla-timeline::before { left: 13px; }
  .vla-phase { padding-left: 26px; }
  .vla-node { left: -2px; width: 24px; height: 24px; font-size: 12px; line-height: 24px; }
  .vla-topic { grid-template-columns: 32px minmax(0, 1fr); }
  .vla-lesson { grid-column: 2; justify-self: start; }
  .vla-phase-title { font-size: 17px; }
}
@media (prefers-reduced-motion: reduce) { .vla-phase summary::after { transition: none; } }

/* track hub (/vla/) */
.vla-road, .vla-papers-tile { display: flex; flex-direction: column; gap: 4px; margin: 0 0 28px; padding: 16px 18px; background: var(--panel); border: 1px solid var(--cobalt); border-left-width: 4px; border-radius: 8px; color: var(--ink); text-decoration: none; max-width: 640px; }
.vla-road:hover, .vla-papers-tile:hover { background: var(--cobalt-2); }
.vla-road strong, .vla-papers-tile strong { font-size: 19px; line-height: 1.25; }
.vla-empty { color: var(--ink-2); margin: 0 0 24px; max-width: 60ch; padding: 12px 14px; border: 1px dashed var(--rule); border-radius: 8px; }

/* prerequisites */
.vla-pre { margin-top: 30px; }
.vla-pre-groups { list-style: none; margin: 0; padding: 0; display: grid; gap: 22px; }
.vla-pre-group { padding-left: 14px; border-left: 3px solid var(--cobalt-2); }
.vla-pre-group:nth-child(2) { border-left-color: var(--cobalt); }
.vla-pre-group:nth-child(3) { border-left-color: var(--green); }
.vla-pre-group:nth-child(4) { border-left-color: var(--orange); }
.vla-pre-group h3 { margin: 0; font-size: 17px; }
.vla-pre-group > p { margin: 2px 0 10px; color: var(--ink-2); font-size: 14px; }
.vla-modules { list-style: none; margin: 0; padding: 0; display: grid; gap: 10px; grid-template-columns: repeat(auto-fill, minmax(min(100%, 380px), 1fr)); align-items: start; }
.vla-module details { background: var(--panel); border: 1px solid var(--rule); border-radius: 10px; }
.vla-module details[open] { border-color: var(--cobalt); }
.vla-module summary { list-style: none; cursor: pointer; display: grid; gap: 6px; padding: 12px 40px 12px 14px; position: relative; border-radius: 10px; }
.vla-module summary::-webkit-details-marker { display: none; }
.vla-module summary::after { content: ''; position: absolute; right: 16px; top: 20px; width: 8px; height: 8px; border-right: 2px solid var(--ink-3); border-bottom: 2px solid var(--ink-3); transform: rotate(45deg); }
.vla-module details[open] > summary::after { transform: rotate(-135deg); top: 24px; }
.vla-module summary:hover { background: var(--grid); }
.vla-module .vla-phase-title { font-size: 17px; }
.vla-level { display: inline-block; margin-left: 6px; padding: 1px 8px; border-radius: 999px; font-size: 11.5px; font-weight: 700; letter-spacing: 0; text-transform: none; border: 1px solid var(--rule); color: var(--ink-2); background: var(--paper); vertical-align: 1px; }
.vla-level-essential { color: var(--cobalt); border-color: var(--cobalt); }
.vla-level-recommended { color: var(--green); border-color: var(--green); }
.vla-level-learn-along { color: var(--ink-2); border-style: dashed; }
.vla-pre + .vla-bar { margin-top: 36px; }