/* Expand a knowledge node without forcing a course sequence. */
.deep-study{margin-top:26px;padding-top:18px;border-top:1px solid var(--line);min-width:0}
.deep-study-header{background:#edf6f4;border:1px solid #d6e9e4;border-radius:14px;padding:14px 16px;margin-bottom:16px}
.deep-study-header p{font-size:.82rem;color:#476a63;margin:0}
.deep-study-section{padding:14px 0;border-bottom:1px solid var(--line)}
.deep-study-section h3{font-size:1.08rem;margin:0 0 8px}
.deep-study-section p{line-height:1.95;margin:0;white-space:pre-line}
.deep-study-section.deep-example{background:#f4f8fa;padding:17px;border-radius:13px;border:1px solid #dfebf0;margin:10px 0}
.deep-study-source{margin-top:15px;padding:16px;border:1px solid var(--line);border-radius:12px;background:#fafcfe;display:flex;flex-direction:column;gap:8px;min-width:0}
.deep-study-source a{color:#126b65;text-decoration:underline;overflow-wrap:anywhere}
.deep-study-source p{color:var(--muted);font-size:.77rem;margin:0}
.concept-notebook label{display:block;font-weight:650;font-size:.88rem;margin:10px 0 5px}
.concept-notebook textarea{width:100%;padding:12px;border:1px solid #bdcfda;border-radius:10px;background:white;resize:vertical;color:var(--ink);min-height:88px}
.concept-notebook .action-row{display:flex;gap:14px;align-items:center;flex-wrap:wrap;margin-top:12px}
[dir="ltr"] .deep-study,[dir="ltr"] .concept-notebook{text-align:left}
@media(max-width:640px){.deep-study-source{padding:12px}.deep-study-section.deep-example{padding:12px}}
/* v1.9: self-contained, RTL/LTR symmetrical numerical foundation studies */
.foundation-review{margin-top:28px;padding:22px;border-radius:16px;border:1px solid #cbdae5;background:#fff;min-width:0;overflow-wrap:anywhere}
.foundation-review h2{font-size:1.4rem;margin:6px 0}.foundation-review h3{font-size:1.04rem;margin:0 0 10px;color:#163d4d}
.foundation-review p,.foundation-review li{font-size:.95rem;line-height:1.9}
.foundation-review-header{padding:16px;background:#edf6f5;border-radius:12px;margin-bottom:20px}
.foundation-review-header p{color:#3c5857;margin:5px 0}
.foundation-review>div:not(:last-child){border-bottom:1px solid #e2eaf0;padding:15px 0}
.foundation-review .foundation-derivation{background:#f7fafc;padding:18px!important;border-radius:12px;border:1px solid #e2eaf0}
.foundation-derivation ol{padding-inline-start:25px;margin:0}.foundation-derivation li{margin:7px 0}
.foundation-probe{margin-top:15px}.foundation-probe>p{margin:5px 0 15px}
.foundation-controls{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,200px),1fr));gap:18px;margin:16px 0}
.foundation-field{display:flex;flex-direction:column;gap:8px;font-weight:600;font-size:.86rem}
.foundation-field input{width:100%;accent-color:#17817e;min-height:26px}.foundation-field output{align-self:start;border-radius:6px;background:#dff1ed;padding:3px 12px;font-variant-numeric:tabular-nums}
.foundation-metrics{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,140px),1fr));gap:9px}
.foundation-metric{border:1px solid #dce9ed;border-radius:9px;padding:10px;background:#f8fcfc;display:flex;flex-direction:column;gap:4px}
.foundation-metric span{font-size:.76rem;color:#455c65}.foundation-metric strong{font-size:1.07rem;font-variant-numeric:tabular-nums}
.foundation-review .foundation-trace{display:flex;flex-wrap:wrap;gap:8px;color:#36576b;font-size:.82rem}
.foundation-interpret{color:#3d5962}.foundation-review .foundation-caveat{background:#fff9f0;padding:14px!important;border:1px solid #ecd9b2;border-radius:10px;margin:12px 0}
.foundation-question{background:#f4f6fc;padding:14px!important;border-radius:10px;margin-top:10px}
.foundation-citation{display:flex;flex-direction:column;gap:7px;padding:18px 0 2px}.foundation-citation a{color:#10685f;text-decoration:underline}.foundation-citation small{color:#607079;line-height:1.8}
[dir="ltr"] .foundation-review{text-align:left}
@media(max-width:580px){.foundation-review{padding:13px}.foundation-review-header{padding:13px}.foundation-review .foundation-derivation{padding:12px!important}}

.foundation-formula{display:block;direction:ltr;text-align:left;overflow-x:auto;white-space:normal;unicode-bidi:isolate;background:#e9f0f7;padding:12px;border-radius:8px;margin:12px 0 15px;font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:.86rem;line-height:1.8}
/* v1.10 extension uses the exact v1.9 educational surface system. */
.extension-review .extension-bridges{border-top:1px solid #e2eaf0;margin-top:15px;padding:17px 0;display:flex;flex-direction:column;gap:8px}
.extension-bridges a{color:#176e6a;text-decoration:underline;overflow-wrap:anywhere;font-size:.9rem}
.extension-matrix{overflow:auto;max-height:210px;width:max-content;max-width:100%;background:#e9f0f7;border-radius:8px;padding:9px 14px;font:12px/1.65 ui-monospace,Consolas,monospace;margin:11px 0}