.formulation-intro{max-width:72ch;color:var(--mut);margin:0 0 1.2rem}
.formulation-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;align-items:start}
.formulation-card{margin:0!important;border:1px solid var(--line);border-radius:12px;min-width:0;background:var(--panel)}
.formulation-card>summary{display:flex;align-items:baseline;gap:14px;padding:18px;cursor:pointer;font-weight:600;list-style:none}
.formulation-card>summary::after{content:'+';margin-left:auto;color:var(--mut)}
.formulation-card[open]>summary::after{content:'−'}
.formulation-card>summary::-webkit-details-marker{display:none}
.formulation-number{font-size:.72rem;font-variant-numeric:tabular-nums;color:var(--mut)}
.formulation-body{padding:0 18px 18px;font-size:.88rem;line-height:1.6}
.formulation-body section{margin:20px 0;min-width:0}
.formulation-body h3{font-size:.88rem;margin-bottom:8px}
.formulation-body .theory-equation{font-size:.9rem;padding:12px;max-width:100%;overflow:auto}
.formulation-caveat{padding-left:12px;border-left:2px solid var(--line);color:var(--mut)}
.formulation-sources{display:flex;gap:8px;margin-bottom:0}
.formulation-dynamics{margin:12px 0 18px}
@media(max-width:720px){.formulation-grid{grid-template-columns:1fr}.formulation-card>summary{padding:15px}.formulation-body{padding:0 15px 15px}}