/* Textbook Rebuild Patch 2: stable lesson layout */
.textbook-shell{max-width:1080px;margin:0 auto;padding:42px 20px 80px;color:#10233f;}
.textbook-page{background:#f5f7fb;color:#10233f;}
.textbook-lesson{max-width:920px;margin:0 auto;}
.textbook-lesson h1{font-size:clamp(2.35rem,5vw,4.3rem);line-height:1.03;margin:0 0 16px;color:#071c34;letter-spacing:-.04em;}
.textbook-lesson h2{font-size:clamp(1.55rem,2.8vw,2.25rem);margin:44px 0 16px;color:#0a2545;letter-spacing:-.02em;}
.textbook-lesson h3{font-size:1.25rem;margin:24px 0 10px;color:#0a2545;}
.textbook-lesson p,.textbook-lesson li{font-size:1.05rem;line-height:1.76;color:#263b57;}
.textbook-lesson .lead{font-size:1.22rem;line-height:1.65;color:#29476a;margin-bottom:22px;}
.lesson-meta{display:flex;gap:10px;flex-wrap:wrap;margin:12px 0 28px}.lesson-meta span{background:#eaf2ff;color:#174d83;border:1px solid #cfe3ff;border-radius:999px;padding:6px 10px;font-size:.86rem;font-weight:700}.toc-box,.key-box,.check-box{background:#fff;border:1px solid #dae5f2;border-radius:18px;padding:20px 22px;box-shadow:0 10px 26px rgba(16,35,63,.06);margin:20px 0}.toc-box ol{columns:2;gap:36px;margin-bottom:0}.key-box{border-left:6px solid #2563eb}.warning-box{background:#fff8e8;border:1px solid #f7d58a;border-left:6px solid #f5a524;border-radius:18px;padding:18px 20px;margin:22px 0}.example-box{background:#fff;border:1px solid #d7e2ef;border-radius:22px;padding:22px;margin:28px 0;box-shadow:0 14px 35px rgba(16,35,63,.08)}.example-box h3{margin-top:0}.formula-box{background:#f2f7ff;border:1px solid #d5e7ff;border-left:6px solid #2563eb;border-radius:16px;padding:16px 18px;margin:18px 0;color:#10233f}.solution-steps{background:#fbfdff;border:1px solid #e2ebf5;border-radius:16px;padding:14px 18px;margin:16px 0}.diagram-wrap{background:#fff;border:1px solid #dbe6f3;border-radius:18px;padding:14px;margin:18px auto;max-width:760px}.diagram-wrap > svg{display:block;width:100%;height:auto;max-height:480px}.caption{font-size:.93rem!important;color:#61738b!important;margin:8px 4px 0!important}.practice-list{background:#fff;border:1px solid #dbe6f3;border-radius:18px;padding:20px 24px;margin:20px 0}.video-embed{background:#061d37;border-radius:20px;padding:18px;margin:26px 0;color:#fff}.video-embed h3{color:#fff}.ratio{position:relative;width:100%;padding-bottom:56.25%;border-radius:14px;overflow:hidden;background:#000}.ratio iframe{position:absolute;inset:0;width:100%;height:100%;border:0}.mini-nav{display:flex;gap:12px;flex-wrap:wrap;margin-top:30px}.mini-nav a{display:inline-block;background:#0b315e;color:#fff;border-radius:999px;padding:10px 14px;font-weight:700}.mathjax-error{background:#ffecec!important;color:#a40000!important}
@media(max-width:720px){.textbook-shell{padding:28px 14px 60px}.toc-box ol{columns:1}.example-box,.toc-box,.key-box,.practice-list{padding:16px}.diagram-wrap{padding:8px}.textbook-lesson p,.textbook-lesson li{font-size:1rem}.textbook-lesson h1{font-size:2.25rem}.lesson-meta span{font-size:.8rem}}


/* Textbook Rebuild Patch 3: MathJax and textbook consistency fixes */
.textbook-page{background:#f5f7fb!important;color:#10233f!important;}
.textbook-shell{max-width:1080px;margin:0 auto;padding:42px 20px 80px;color:#10233f;}
.textbook-lesson{max-width:920px;margin:0 auto;}
.textbook-lesson mjx-container{max-width:100%;overflow-x:auto;overflow-y:hidden;}
.textbook-lesson mjx-container[display="true"]{font-size:1.04em!important;padding:.25rem 0;}
.textbook-lesson .caption mjx-container{font-size:1em!important;display:inline-block!important;overflow:visible!important;}
.textbook-lesson .caption mjx-container svg,
.diagram-wrap mjx-container svg,
.example-box mjx-container svg{width:auto!important;max-width:none!important;max-height:1.45em!important;display:inline!important;vertical-align:-0.25em!important;}
.diagram-wrap > svg{display:block;width:100%;height:auto;max-height:480px;}
.textbook-lesson .example-box{background:#fff;border:1px solid #d7e2ef;border-radius:22px;padding:24px;margin:30px 0;box-shadow:0 14px 35px rgba(16,35,63,.08);}
.textbook-lesson .example-box .solution-steps{background:#fbfdff;border:1px solid #e2ebf5;border-radius:16px;padding:16px 18px;margin:16px 0;}
.textbook-lesson .diagram-wrap{background:#fff;border:1px solid #dbe6f3;border-radius:18px;padding:14px;margin:20px auto;max-width:780px;}
.textbook-lesson .two-column-notes{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px;align-items:start;}
.textbook-lesson .small-example{background:#ffffff;border:1px solid #dbe6f3;border-radius:18px;padding:16px;}
.textbook-lesson .transformation-rule{display:grid;grid-template-columns:minmax(180px,.8fr) minmax(0,1.4fr);gap:16px;align-items:start;background:#fff;border:1px solid #dae5f2;border-radius:18px;padding:18px 20px;margin:18px 0;box-shadow:0 10px 26px rgba(16,35,63,.05)}
.textbook-lesson .rule-symbol{font-weight:800;color:#0a2545;background:#f2f7ff;border-left:6px solid #2563eb;border-radius:14px;padding:14px;}
.textbook-lesson .video-grid-inline{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px;margin-top:18px;}
.textbook-lesson .video-embed.compact{padding:14px;margin:0;background:#061d37;}
.textbook-lesson .video-embed.compact h3{font-size:1rem;margin:0 0 8px;color:#fff;}
.textbook-lesson .video-embed.compact p{font-size:.92rem;line-height:1.45;color:#cbd9ea;margin:.25rem 0 .7rem;}
@media(max-width:760px){.textbook-lesson .two-column-notes,.textbook-lesson .transformation-rule,.textbook-lesson .video-grid-inline{grid-template-columns:1fr}.textbook-lesson mjx-container[display="true"]{font-size:1em!important}.textbook-lesson .diagram-wrap{padding:8px}.textbook-lesson .example-box{padding:18px}}