/* Textbook Standard Patch 1
   Establishes the online-textbook layout standard across current lesson pages. */
.textbook-page{background:#f5f7fb!important;color:#10233f!important;}
.textbook-shell{max-width:1120px!important;margin:0 auto!important;padding:44px 22px 86px!important;}
.textbook-lesson{max-width:940px!important;margin:0 auto!important;}
.textbook-lesson h1{font-size:clamp(2.4rem,4.8vw,4.4rem)!important;line-height:1.04!important;letter-spacing:-.035em!important;color:#071c34!important;margin:0 0 18px!important;}
.textbook-lesson h2{font-size:clamp(1.55rem,2.7vw,2.25rem)!important;color:#0a2545!important;margin:48px 0 18px!important;line-height:1.16!important;}
.textbook-lesson h3{font-size:1.22rem!important;color:#0a2545!important;line-height:1.25!important;}
.textbook-lesson p,.textbook-lesson li{font-size:1.08rem!important;line-height:1.78!important;color:#263b57!important;}
.textbook-lesson .lead{font-size:1.24rem!important;line-height:1.68!important;color:#29476a!important;}
.toc-box,.key-box,.check-box,.practice-list{background:#fff!important;border:1px solid #dae5f2!important;border-radius:20px!important;box-shadow:0 10px 28px rgba(16,35,63,.06)!important;}
.example-box{background:#fff!important;border:1px solid #d7e2ef!important;border-radius:22px!important;padding:26px!important;margin:34px 0!important;box-shadow:0 16px 38px rgba(16,35,63,.085)!important;}
.solution-steps{background:#fbfdff!important;border:1px solid #e2ebf5!important;border-radius:18px!important;padding:18px 20px!important;margin:18px 0!important;}
.formula-box{background:#f2f7ff!important;border:1px solid #d5e7ff!important;border-left:6px solid #2563eb!important;border-radius:16px!important;padding:18px 20px!important;margin:20px 0!important;color:#10233f!important;font-size:1.08rem!important;overflow-x:auto!important;}
.formula-box mjx-container[jax="SVG"][display="true"],
.example-box mjx-container[jax="SVG"][display="true"],
.practice-list mjx-container[jax="SVG"][display="true"]{font-size:1.08em!important;text-align:center!important;margin:.55rem auto!important;overflow-x:auto!important;overflow-y:hidden!important;max-width:100%!important;}
.textbook-lesson mjx-container[jax="SVG"][display="true"] svg{max-width:100%!important;max-height:none!important;width:auto!important;height:auto!important;}
.textbook-lesson p mjx-container[jax="SVG"] svg,
.textbook-lesson li mjx-container[jax="SVG"] svg,
.textbook-lesson summary mjx-container[jax="SVG"] svg{max-height:1.35em!important;width:auto!important;max-width:none!important;vertical-align:-.25em!important;}
.textbook-lesson .caption mjx-container[jax="SVG"] svg{max-height:1.35em!important;width:auto!important;}
.diagram-wrap{background:#fff!important;border:1px solid #dbe6f3!important;border-radius:18px!important;padding:14px!important;margin:22px auto!important;max-width:780px!important;overflow:hidden!important;}
.diagram-wrap>svg{display:block!important;width:100%!important;height:auto!important;max-height:540px!important;}
.caption{font-size:.98rem!important;line-height:1.55!important;color:#61738b!important;margin:10px 4px 0!important;}
.video-grid-inline{display:grid!important;grid-template-columns:repeat(2,minmax(0,1fr))!important;gap:16px!important;margin-top:18px!important;}
.video-embed{background:#061d37!important;border-radius:20px!important;padding:18px!important;margin:28px 0!important;color:#fff!important;box-shadow:0 14px 35px rgba(6,29,55,.18)!important;}
.video-embed h2,.video-embed h3{color:#fff!important;margin-top:0!important;}
.video-embed p{color:#cbd9ea!important;}
.video-embed.compact{padding:14px!important;margin:0!important;}
.video-embed.compact h3{font-size:1.02rem!important;color:#fff!important;margin:0 0 8px!important;}
.video-embed.compact p{font-size:.95rem!important;line-height:1.5!important;color:#cbd9ea!important;margin:.25rem 0 .75rem!important;}
.solution-toggle{background:#f8fbff!important;border:1px solid #d5e7ff!important;border-radius:16px!important;margin:14px 0!important;overflow:hidden!important;}
.solution-toggle summary{cursor:pointer!important;list-style:none!important;padding:14px 18px!important;font-weight:800!important;color:#0a3d78!important;background:#edf5ff!important;display:flex!important;align-items:center!important;gap:10px!important;}
.solution-toggle summary::-webkit-details-marker{display:none!important;}
.solution-toggle summary::before{content:"＋";font-weight:900;color:#2563eb;}
.solution-toggle[open] summary::before{content:"−";}
.solution-toggle .solution-body{padding:16px 18px 18px!important;}
.practice-list ol{padding-left:1.3rem!important;}
.practice-item{margin:1.05rem 0 1.25rem!important;}
.standard-note{background:#eef7ff!important;border-left:6px solid #38bdf8!important;border-radius:16px!important;padding:16px 18px!important;margin:20px 0!important;}
@media(max-width:760px){.textbook-shell{padding:30px 14px 70px!important}.textbook-lesson p,.textbook-lesson li{font-size:1.02rem!important}.example-box{padding:18px!important}.formula-box{padding:15px 16px!important}.video-grid-inline{grid-template-columns:1fr!important}.diagram-wrap{padding:8px!important}.textbook-lesson h1{font-size:2.25rem!important}}


/* MathJax escape fix 1: keep displayed formulae readable and prevent oversized formula boxes. */
.formula-box mjx-container[jax="SVG"][display="true"]{font-size:1.18em!important;line-height:1.35!important;}
.solution-steps .formula-box mjx-container[jax="SVG"][display="true"]{font-size:1.15em!important;}
.textbook-lesson mjx-container[jax="SVG"][display="true"]{max-width:100%!important;overflow-x:auto!important;overflow-y:hidden!important;}