/* Biology lesson MedStudy-style restyle — additive, scoped to .blr-* / body.blr-page */
body.blr-page{background:var(--blr-paper,#eef1f6)}
:root{
  --blr-paper:#eef1f6; --blr-surface:#ffffff; --blr-ink:#1c2430; --blr-muted:#5b6472; --blr-border:#dde3ec;
  --blr-blue:#1a3a5c; --blr-blue-tint:#eaf1fb; --blr-blue-line:#c7d9ef;
  --blr-red:#b8382a; --blr-red-tint:#fdf1f0; --blr-red-line:#f0c7c0;
  --blr-gold:#9c7209; --blr-gold-tint:#fdf7e3; --blr-gold-line:#ecdca0;
  --blr-green:#1a6b3c; --blr-green-tint:#eff9f2; --blr-green-line:#bfe3cc;
  --blr-purple:#6428b4; --blr-purple-tint:#f4eefc; --blr-purple-line:#ddc8f2;
  --blr-chrome:linear-gradient(135deg,#12233d 0%,#1e3a5f 60%,#2c5282 100%);
  --blr-chrome-ink:#f2f6fb; --blr-chrome-sub:#9fb6d1; --blr-chrome-accent:#7dd3fc;
  --blr-shadow:0 1px 2px rgba(20,30,50,.05), 0 6px 18px rgba(20,30,50,.07);
}
@media (prefers-color-scheme: dark){
  body.blr-page:not([data-theme="light"]){
    --blr-paper:#0b1220; --blr-surface:#111a2c; --blr-ink:#e4eaf3; --blr-muted:#93a1b8; --blr-border:#233046;
    --blr-blue:#7dd3fc; --blr-blue-tint:rgba(125,211,252,.10); --blr-blue-line:rgba(125,211,252,.32);
    --blr-red:#f4897c; --blr-red-tint:rgba(244,137,124,.10); --blr-red-line:rgba(244,137,124,.32);
    --blr-gold:#f0c352; --blr-gold-tint:rgba(240,195,82,.10); --blr-gold-line:rgba(240,195,82,.32);
    --blr-green:#5fd6a0; --blr-green-tint:rgba(95,214,160,.10); --blr-green-line:rgba(95,214,160,.32);
    --blr-purple:#c3a4f5; --blr-purple-tint:rgba(195,164,245,.10); --blr-purple-line:rgba(195,164,245,.32);
    --blr-shadow:0 1px 2px rgba(0,0,0,.3), 0 8px 22px rgba(0,0,0,.35);
  }
}
body.blr-page[data-theme="dark"]{
  --blr-paper:#0b1220; --blr-surface:#111a2c; --blr-ink:#e4eaf3; --blr-muted:#93a1b8; --blr-border:#233046;
  --blr-blue:#7dd3fc; --blr-blue-tint:rgba(125,211,252,.10); --blr-blue-line:rgba(125,211,252,.32);
  --blr-red:#f4897c; --blr-red-tint:rgba(244,137,124,.10); --blr-red-line:rgba(244,137,124,.32);
  --blr-gold:#f0c352; --blr-gold-tint:rgba(240,195,82,.10); --blr-gold-line:rgba(240,195,82,.32);
  --blr-green:#5fd6a0; --blr-green-tint:rgba(95,214,160,.10); --blr-green-line:rgba(95,214,160,.32);
  --blr-purple:#c3a4f5; --blr-purple-tint:rgba(195,164,245,.10); --blr-purple-line:rgba(195,164,245,.32);
  --blr-shadow:0 1px 2px rgba(0,0,0,.3), 0 8px 22px rgba(0,0,0,.35);
}

.blr-chrome{background:var(--blr-chrome);color:var(--blr-chrome-ink);padding:12px 22px;display:flex;align-items:center;justify-content:space-between;gap:14px;flex-wrap:wrap;row-gap:8px;border-radius:12px;margin:14px auto 0;max-width:1180px;box-shadow:var(--blr-shadow);font-family:Inter,'Segoe UI',sans-serif}
.blr-chrome .blr-crumb{font-size:11.5px;color:var(--blr-chrome-sub);letter-spacing:.02em;margin-bottom:3px}
.blr-chrome .blr-title{font-size:15px;font-weight:700;font-family:'Noto Sans Tamil',Inter,sans-serif}
.blr-actions{display:flex;gap:8px;flex-wrap:wrap}
.blr-chip{font:600 12px/1 Inter,sans-serif;color:var(--blr-chrome-ink)!important;text-decoration:none!important;padding:7px 13px;border-radius:7px;background:rgba(255,255,255,.10);border:1px solid rgba(255,255,255,.20);white-space:nowrap}
.blr-chip:hover{background:rgba(255,255,255,.22)}
.blr-chip.qbank{background:rgba(255,255,255,.20);border-color:rgba(255,255,255,.34)}
.blr-chip.mindmap{background:rgba(125,90,220,.34);border-color:rgba(196,168,245,.5)}

.blr-layout{max-width:1180px;margin:0 auto;padding:18px 20px 50px;display:grid;grid-template-columns:230px minmax(0,1fr);gap:22px;align-items:start}

.blr-side{position:sticky;top:16px;display:flex;flex-direction:column;gap:12px}
@media (max-width:900px){.blr-layout{grid-template-columns:1fr}.blr-side{display:none!important}}
.blr-card{background:var(--blr-surface);border:1px solid var(--blr-border);border-radius:12px;box-shadow:var(--blr-shadow);overflow:hidden}
.blr-side-h{font:700 11px/1 Inter,sans-serif;letter-spacing:.06em;text-transform:uppercase;color:#fff;background:var(--blr-blue);padding:10px 14px}
.blr-side nav{display:flex;flex-direction:column}
.blr-side nav a{font-size:12.5px;color:var(--blr-muted);text-decoration:none;padding:8px 14px;border-left:3px solid transparent;border-bottom:1px solid var(--blr-border)}
.blr-side nav a:last-child{border-bottom:none}
.blr-side nav a:hover{background:var(--blr-blue-tint);border-left-color:var(--blr-blue);color:var(--blr-blue);font-weight:600}
.blr-tools a{display:flex;align-items:center;gap:8px;font-size:12.5px;text-decoration:none;color:var(--blr-ink);padding:9px 14px;border-bottom:1px solid var(--blr-border)}
.blr-tools a:last-child{border-bottom:none}
.blr-tools a:hover{background:var(--blr-paper)}
.blr-dot{width:7px;height:7px;border-radius:50%;flex:none}
.blr-dot.qbank{background:var(--blr-red)} .blr-dot.mindmap{background:var(--blr-purple)}
.blr-dot.revise{background:var(--blr-green)} .blr-dot.aki{background:var(--blr-blue)}

.blr-hero{background:var(--blr-chrome);color:var(--blr-chrome-ink);border-radius:14px;padding:22px 26px;margin-bottom:18px;box-shadow:var(--blr-shadow)}
.blr-hero .blr-eyebrow{font:700 11px/1 Inter,sans-serif;letter-spacing:.08em;text-transform:uppercase;color:var(--blr-chrome-accent);margin-bottom:8px}
.blr-hero h1{font-size:21px;font-weight:800;margin:0;text-wrap:balance;color:var(--blr-chrome-ink)}

.blr-hero-meta{margin-top:10px;display:flex;gap:8px;flex-wrap:wrap}
.blr-hero-meta .pill{background:rgba(255,255,255,.14)!important;border:1px solid rgba(255,255,255,.2)!important;color:var(--blr-chrome-ink)!important;border-radius:6px;padding:4px 10px;font:600 12px/1 Inter,sans-serif}

.blr-sec{background:var(--blr-surface);border:1px solid var(--blr-border);border-radius:12px;box-shadow:var(--blr-shadow);margin-bottom:18px;overflow:hidden}
.blr-sec-h{display:flex;align-items:center;gap:12px;padding:13px 20px;border-bottom:1px solid var(--blr-border)}
.blr-sec-h .blr-n{font:700 12px/1 Inter,sans-serif;background:var(--blr-blue);color:#fff;border-radius:6px;padding:4px 10px;flex:none}
.blr-sec-h h3{margin:0!important;font-size:16px!important;font-weight:700!important;color:var(--blr-blue)!important;border:none!important;padding:0!important}
.blr-sec-b{padding:18px 20px;color:var(--blr-ink)}
.blr-sec-b p{color:var(--blr-ink)}

/* re-skin existing lesson box classes to the new palette (no markup change needed) */
.blr-page .lo{background:var(--blr-blue-tint)!important;border:none!important;border-left:4px solid var(--blr-blue)!important;border-radius:0 10px 10px 0!important;color:var(--blr-ink)!important}
.blr-page .lo .lo-h{color:var(--blr-blue)!important}
.blr-page .lo li{color:var(--blr-ink)!important}
.blr-page .nie-note{background:var(--blr-gold-tint)!important;border:none!important;border-left:4px solid var(--blr-gold)!important;color:var(--blr-ink)!important}
.blr-page .nie-note b{color:var(--blr-gold)!important}
.blr-page .callout{background:var(--blr-green-tint)!important;border:none!important;border-left:4px solid var(--blr-green)!important;border-radius:0 10px 10px 0!important;color:var(--blr-ink)!important;padding:14px 18px!important}
.blr-page table{width:100%;border-collapse:collapse;font-size:13.8px;margin:6px 0 4px}
.blr-page th{background:var(--blr-blue)!important;color:#fff!important;text-align:left;font:600 12px/1 Inter,sans-serif;padding:9px 12px}
.blr-page td{padding:9px 12px;border-bottom:1px solid var(--blr-border)}
.blr-page tr:nth-child(even) td{background:var(--blr-paper)}

.blr-recall{background:var(--blr-chrome);color:var(--blr-chrome-ink);border-radius:12px;padding:16px 20px;margin-top:20px;box-shadow:var(--blr-shadow)}
.blr-recall .blr-lbl{font:700 10.5px/1 Inter,sans-serif;letter-spacing:.07em;text-transform:uppercase;color:var(--blr-chrome-accent);margin-bottom:7px;display:block}

/* Chemistry's existing box classes, re-skinned to the same palette (no markup change) */
.blr-page .callout{background:var(--blr-blue-tint)!important;border:none!important;border-left:4px solid var(--blr-blue)!important;border-radius:0 10px 10px 0!important;color:var(--blr-ink)!important;padding:14px 18px!important}
.blr-page .callout .label{color:var(--blr-blue)!important}
.blr-page .callout.trap{background:var(--blr-gold-tint)!important;border-left-color:var(--blr-gold)!important}
.blr-page .callout.trap .label{color:var(--blr-gold)!important}
.blr-page .callout p,.blr-page .callout li{color:var(--blr-ink)!important}