/* Chemistry Lab v1.5: Lessons 3 and 4 (2D labs) share the 3D lessons' chrome.
 * The stage is the same rounded, framed panel; the scene fills it edge to edge. */
.flat-lab .flat-stage{height:clamp(540px,56vw,640px);background:transparent}
.temperature-lab .flat-stage{height:clamp(480px,44vw,540px)}
.flat-lab .flat-stage .scene-mount>*{position:absolute;inset:0;min-height:0}
.flat-lab .scene-loading{position:absolute;inset:0;display:grid;place-items:center;margin:0;color:var(--muted);font-size:15px}
.builder-builds{justify-content:flex-start;padding:14px 20px 12px}
.builder-builds .toolbar-label{font-size:13px;color:var(--muted);margin-right:4px}
.builder-builds button{border-radius:999px!important;padding:9px 15px!important}
.builder-builds button[aria-pressed=true]{color:var(--teal);border-color:var(--teal)!important;box-shadow:0 0 0 3px color-mix(in srgb,var(--teal) 18%,transparent)}
.flat-lab .scene-explanation[data-part=proton] .scene-explanation-symbol{background:#f9e4bc;color:#86500c}
.flat-lab .scene-explanation[data-part=electron] .scene-explanation-symbol,.flat-lab .scene-explanation[data-part=shells] .scene-explanation-symbol{background:color-mix(in srgb,#4A86FF 22%,var(--surface));color:#7FA9FF}
:root[data-theme=light] .flat-lab .scene-explanation[data-part=electron] .scene-explanation-symbol,:root[data-theme=light] .flat-lab .scene-explanation[data-part=shells] .scene-explanation-symbol{color:#2E6BE6}
@media(max-width:680px){
 .flat-lab .flat-stage{height:min(640px,max(540px,calc(100dvh - var(--header-height,64px) - 92px)));max-height:none}
 .temperature-lab .flat-stage{height:min(560px,max(470px,calc(100dvh - var(--header-height,64px) - 230px)))}
 /* The explanation card below already carries the full sentence; keep the phone caption short. */
 .temperature-lab .cl-hc-cap-body{display:none}
 .builder-builds{display:flex!important;flex-wrap:nowrap;overflow-x:auto;scrollbar-width:none;padding:12px 13px}
 .builder-builds::-webkit-scrollbar{display:none}
 .builder-builds button{flex:none;font-size:13px!important;min-height:42px!important}
}
/* v1.6: seven activities. An odd last card stretches across both columns so the grid closes cleanly. */
@media(min-width:681px){.ready-grid>.module-card:last-child:nth-child(odd){grid-column:1/-1;padding-right:min(34%,330px)}.ready-grid>.module-card:last-child:nth-child(odd) .card-art{top:22px;right:34px;width:200px;max-width:200px}}