/* free_body.css — object + force arrows (see free_body.js). */
.fb-svg { display: block; width: 100%; height: auto; }
.fb-ground { stroke: rgba(148, 163, 184, 0.4); stroke-width: 2; }
.fb-box { fill: rgba(104, 130, 176, 0.22); stroke: #8fa8cf; stroke-width: 1.8; }
.fb-mass { fill: #ede9fe; font-size: 11px; font-weight: 700; }
.fb-arrow { stroke-width: 3; stroke-linecap: round; }
.fb-w { stroke: #94a3b8; color: #94a3b8; } .fb-n { stroke: #94a3b8; color: #94a3b8; }
.fb-f { stroke: #34d399; color: #34d399; } .fb-fr { stroke: #fb7185; color: #fb7185; }
.fb-res { stroke: #fbbf24; color: #fbbf24; stroke-width: 3.6; }
.fb-lab { font-size: 9.5px; font-weight: 700; paint-order: stroke; stroke: #0a0f1a; stroke-width: 2.6px; stroke-linejoin: round; }
.fb-lab.fb-w, .fb-lab.fb-n { fill: #cbd5e1; } .fb-lab.fb-f { fill: #6ee7b7; } .fb-lab.fb-fr { fill: #fda4af; } .fb-lab.fb-res { fill: #fde68a; }