:root{
  --bb-ink:#171b21;--bb-muted:#657083;--bb-line:#cfd5de;--bb-blue:#3158d7;--bb-top:#e9f0fb;
  --bb-yellow:#ffd633;--bb-paper:#fff;--bb-panel:#f5f7fa;--bb-green:#0f7d62;
  --bb-ui:'Inter',-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  --bb-serif:'Noto Serif',Georgia,'Times New Roman',serif;
  --bb-display:'Rubik',Inter,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif
}
body.brain-bee-page{background:#faf8f3;color:var(--bb-ink)}
body.bb-access-pending{visibility:hidden}
body.bb-not-found-page{background:#f7f5ef}
.bb-hidden{display:none!important}
.bb-shell{max-width:1180px;margin:0 auto;padding:42px 24px 82px}
.bb-hero{display:grid;grid-template-columns:minmax(0,1.5fr) minmax(280px,.7fr);gap:36px;align-items:end;padding:34px 0 28px;border-bottom:1px solid #ddd8cd}
.bb-eyebrow{font:800 11px/1 var(--bb-ui);letter-spacing:.15em;text-transform:uppercase;color:#9a7427;margin-bottom:15px}
.bb-hero h1{margin:0;color:#102a43;font:650 clamp(42px,6vw,74px)/.98 var(--bb-display);letter-spacing:-.045em}
.bb-hero h1 em{color:#3158d7;font-style:italic}
.bb-hero p{margin:16px 0 0;color:#42566d;font:500 16px/1.65 var(--bb-ui);max-width:720px}
.bb-private{border:1px solid #d7ccb0;background:#fffaf0;padding:18px 20px;font:600 12px/1.55 var(--bb-ui);color:#634e24}
.bb-private b{display:block;margin-bottom:4px;text-transform:uppercase;letter-spacing:.1em;font-size:10px}
.bb-tabs{display:flex;gap:18px;align-items:center;margin:28px 0 22px;border-bottom:1px solid #d8dde6}
.bb-tab{border:0;background:none;padding:10px 2px 14px;color:#3158d7;font:750 13px var(--bb-ui);text-decoration:none;position:relative}
.bb-tab.active::after{content:"";position:absolute;left:0;right:0;bottom:-1px;height:3px;background:#3158d7}
.bb-units{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:20px}
.bb-unit-card{background:#fff;border:1px solid #dde2e9;border-radius:14px;padding:25px;box-shadow:0 14px 38px rgba(16,42,67,.07);position:relative;overflow:hidden}
.bb-unit-card::before{content:"";position:absolute;left:0;top:0;bottom:0;width:4px;background:linear-gradient(#3158d7,#c89b3c)}
.bb-unit-kicker{font:800 10px var(--bb-ui);letter-spacing:.12em;text-transform:uppercase;color:#6e7887;margin-bottom:10px}
.bb-unit-card h2{margin:0 0 9px;color:#162d45;font:650 25px/1.15 var(--bb-display)}
.bb-unit-meta{font:500 12px/1.55 var(--bb-ui);color:var(--bb-muted);margin-bottom:20px}
.bb-unit-actions{display:flex;gap:10px;flex-wrap:wrap}
.bb-start{border:0;border-radius:999px;min-height:40px;padding:0 20px;background:#eaf0ff;color:#2549ba;font:800 12px var(--bb-ui);box-shadow:0 8px 18px rgba(31,60,134,.11)}
.bb-start.primary{background:#3158d7;color:#fff}.bb-start:hover{transform:translateY(-1px)}
.bb-progress{margin-top:15px;border-top:1px solid #e4e7ec;padding-top:13px;color:#697382;font:600 11px/1.45 var(--bb-ui)}
.bb-gate{max-width:720px;margin:90px auto;background:#fff;border:1px solid #d8dde6;border-radius:14px;padding:38px;text-align:center;box-shadow:0 18px 55px rgba(16,42,67,.08)}
.bb-gate h1{font:650 34px var(--bb-display);color:#102a43}.bb-gate p{color:#657083;line-height:1.65}
.bb-gate.bb-not-found{max-width:760px;margin:clamp(76px,12vh,132px) auto 110px;background:transparent;border:0;border-radius:0;padding:38px 24px;box-shadow:none}
.bb-not-found-code{font:800 clamp(72px,11vw,132px)/.85 var(--bb-ui);letter-spacing:-.08em;color:#3158d7}
.bb-gate.bb-not-found h1{margin:24px 0 10px;font:650 clamp(34px,5vw,54px)/1.04 var(--bb-display);letter-spacing:-.035em;color:#102a43}
.bb-gate.bb-not-found p{max-width:520px;margin:0 auto 28px;font:500 15px/1.7 var(--bb-ui);color:#657083}

/* Display titles use the Ready by May Rubik system; lesson and question copy stays serif. */
.bb-dialog h2,.bb-page-head h1,.bb-tier-head h2,.bb-empty-practice h2,.bb-practice-review-head h2,.bb-study-block>header h2,.bb-study-complete h1,.bb-finish-box h2{font-family:var(--bb-display)}

/* Launch dialog */
.bb-modal{position:fixed;inset:0;z-index:120;background:rgba(16,22,31,.66);display:flex;align-items:center;justify-content:center;padding:22px;font-family:var(--bb-ui)}
.bb-dialog{width:min(620px,100%);background:#fff;border-radius:13px;padding:30px;box-shadow:0 24px 70px rgba(0,0,0,.24);position:relative}
.bb-dialog h2{margin:0 42px 7px 0;font-size:25px}.bb-dialog p{color:#606b79;line-height:1.55;margin:0 0 20px}
.bb-dialog-close{position:absolute;right:20px;top:16px;border:0;background:none;font-size:28px}
.bb-timer-option{display:flex;align-items:center;gap:13px;border:1px solid #d8dde6;border-radius:9px;padding:15px;margin:18px 0}
.bb-switch{width:48px;height:27px;border:0;border-radius:999px;background:#cbd1da;padding:3px;position:relative;flex:none}
.bb-switch::after{content:"";position:absolute;left:3px;top:3px;width:21px;height:21px;border-radius:50%;background:#fff;transition:.15s}
.bb-switch.on{background:#3158d7}.bb-switch.on::after{left:24px}
.bb-dialog-actions{display:flex;justify-content:flex-end;gap:10px;margin-top:23px}.bb-dialog-actions .bb-start{min-width:118px}
.bb-framework-note{border-left:4px solid #c89b3c;background:#fbf8ef;padding:13px 15px;color:#63583c;font-size:12px;line-height:1.55}

/* Bluebook-like Study and Practice surface */
.bb-bluebook{position:fixed;inset:0;z-index:90;background:#fff;display:grid;grid-template-rows:auto 1fr auto;font-family:var(--bb-ui)}
.bb-test-top{position:relative;background:var(--bb-top);padding:18px 28px 13px;min-height:102px;display:flex;align-items:flex-start;gap:20px}
.bb-test-top::after,.bb-test-foot::before{content:"";position:absolute;left:0;right:0;height:2px;background-image:linear-gradient(to right,#171b21 0 86%,transparent 86%);background-size:calc(100%/56) 2px;background-repeat:repeat-x}
.bb-test-top::after{bottom:0}.bb-test-foot::before{top:0}
.bb-section-title{font-size:20px;font-weight:700}.bb-section-sub{font-size:13px;font-weight:650;margin-top:9px}
.bb-timer{position:absolute;left:50%;top:17px;transform:translateX(-50%);display:flex;flex-direction:column;align-items:center;gap:7px}
.bb-time{font-size:22px;font-weight:700;font-variant-numeric:tabular-nums}.bb-hide-time{border:1.5px solid #222;border-radius:999px;background:transparent;padding:2px 13px;font-size:12px;font-weight:700}
.bb-tools{margin-left:auto;display:flex;align-items:flex-start;gap:23px}
.bb-tool{border:0;background:none;min-width:65px;display:flex;flex-direction:column;align-items:center;gap:4px;font:650 11px/1.1 var(--bb-ui);color:#20252b}
.bb-tool-icon{height:26px;display:flex;align-items:center;justify-content:center;font-size:18px;font-weight:800}.bb-tool.active span:last-child,.bb-tool.annotation-on span:last-child{text-decoration:underline;text-underline-offset:3px}.bb-tool.annotation-on .bb-tool-icon{color:#3158d7}
.bb-study-main{min-height:0;display:flex;overflow:hidden;background:#fff}
.bb-outline{width:250px;flex:none;background:#f6f7f9;border-right:1px solid #d4d9e1;padding:24px 17px;overflow:auto}
.bb-outline b{display:block;font-size:11px;letter-spacing:.1em;text-transform:uppercase;color:#6c7582;margin:0 8px 14px}
.bb-outline button{width:100%;border:0;border-radius:7px;background:transparent;text-align:left;padding:11px 12px;color:#2c3540;font:650 12px/1.35 var(--bb-ui)}
.bb-outline button:hover,.bb-outline button.active{background:#e8edf6;color:#2447af}
.bb-reader{flex:1;min-width:0;overflow:auto;scroll-behavior:smooth}.bb-page{max-width:900px;margin:0 auto;padding:42px 52px 100px}
.bb-page-head{padding-bottom:22px;border-bottom:2px solid #20242a;margin-bottom:28px}.bb-page-head .unit{font:800 11px var(--bb-ui);letter-spacing:.13em;text-transform:uppercase;color:#3158d7}.bb-page-head h1{font:700 38px/1.15 var(--bb-serif);margin:9px 0 8px}.bb-page-head p{font:500 13px/1.55 var(--bb-ui);color:#657083;margin:0}
.bb-tier{scroll-margin-top:24px;margin-bottom:30px;border:1px solid #d5dbe4;background:#fff}
.bb-tier-head{display:flex;align-items:center;gap:13px;padding:16px 18px;background:#f1f4f8;border-bottom:1px solid #d5dbe4}.bb-tier-label{background:#171b21;color:#fff;padding:6px 8px;font:800 10px var(--bb-ui)}.bb-tier-head h2{margin:0;font:700 20px var(--bb-serif)}
.bb-tier-copy{padding:20px 22px 24px;font:400 17px/1.75 var(--bb-serif);cursor:text}.bb-tier-copy p{margin:0 0 14px}.bb-tier-copy .bb-placeholder{border:1px dashed #aeb7c4;background:#fafbfc;padding:18px;font:600 13px/1.65 var(--bb-ui);color:#596575}
.bb-source-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px;margin-top:14px}.bb-source-grid div{padding:12px;background:#f7f8fa;border:1px solid #e1e4e9;font:600 11px/1.5 var(--bb-ui);color:#536070}.bb-source-grid b{display:block;color:#1f2933;margin-bottom:3px}
.bb-notesbar{position:relative;height:100%;flex:0 0 300px;min-width:0;background:#f3f4f6;border-left:1px solid #cfd4dc;border-right:1px solid #cfd4dc;overflow:visible}.bb-notesbar-scroll{height:100%;overflow:auto;padding:16px}.bb-notesbar h3{margin:0 0 14px;font-size:12px;letter-spacing:.08em;text-transform:uppercase;color:#626c79}.bb-notesbar.collapsed{flex-basis:18px;min-width:18px}.bb-notesbar.collapsed .bb-notesbar-scroll{display:none}.bb-notescollapse{position:absolute;left:0;bottom:18px;width:32px;height:38px;background:#7d848d;color:#fff;border:1px solid #b8bec8;border-left:0;border-radius:0 19px 19px 0;cursor:pointer;display:flex;align-items:center;justify-content:center;font-size:17px;z-index:5;box-shadow:none}.bb-notescollapse.out{left:-31px;border-right:0;border-left:1px solid #b8bec8;border-radius:19px 0 0 19px}.bb-notescollapse:hover{background:#000}.bb-note{background:#fffdf5;border:1px solid #e8e1c4;border-radius:10px;padding:12px;margin-bottom:12px}.bb-note .quote{display:block;background:#ffe9a8;border:0;border-radius:4px;padding:3px 6px;font:600 11px/1.45 var(--bb-ui);margin:0 0 8px;text-align:left;cursor:pointer}.bb-note textarea{width:100%;min-height:64px;border:1px solid #ccd2dc;border-radius:7px;padding:8px;font:12px/1.45 var(--bb-ui);resize:vertical}.bb-note .delete-note{float:right;border:0;background:none;color:#697382;cursor:pointer}.bb-note .delete-note:hover{color:#9c3434}
.bb-test-foot{position:relative;min-height:75px;background:var(--bb-top);display:flex;align-items:center;padding:13px 28px}.bb-candidate{font-size:14px;font-weight:700}.bb-foot-center{position:absolute;left:50%;transform:translateX(-50%);font-size:12px;font-weight:700}.bb-foot-actions{margin-left:auto;display:flex;gap:10px}.bb-foot-btn{border:0;border-radius:999px;background:#3158d7;color:#fff;min-height:40px;padding:0 23px;font:800 12px var(--bb-ui)}.bb-foot-btn.secondary{background:#fff;color:#1f2933;border:1px solid #9ca5b1}

/* AP exam annotation kernel, reused for Study */
.bb-tier-copy{cursor:text}.hl{cursor:pointer;border-radius:2px;transition:background .1s}.hl.c-yellow{background:#ffe9a8}.hl.c-blue{background:#d6ebff}.hl.c-pink{background:#ffd6ec}.hl.c-yellow:hover{background:#ffd34d}.hl.c-blue:hover{background:#9ccbff}.hl.c-pink:hover{background:#ff9fd1}.hl.u{border-bottom:2px solid #333}.hl.u-dashed{border-bottom-style:dashed}.hl.u-dotted{border-bottom-style:dotted}
.bb-selbar{position:fixed;z-index:140;display:flex;align-items:center;gap:8px;background:#fff;border:1px solid #cfd4dc;box-shadow:0 6px 20px rgba(0,0,0,.18);border-radius:30px;padding:7px 12px}.bb-sw{box-sizing:border-box;width:30px;height:30px;border-radius:50%;border:1px solid #cfd4dc;background:#fff;cursor:pointer;display:flex;align-items:center;justify-content:center;font-weight:700}.bb-sw.y{background:#ffe9a8}.bb-sw.b{background:#d6ebff}.bb-sw.p{background:#ffd6ec}.bb-sw.act{border:2.4px solid #1f2933;box-shadow:none}.bb-note-add{background:#eef0f3}.bb-sel-divider{width:1px;height:22px;background:#cfd4dc}
.bb-ulmenu{position:fixed;z-index:142;background:#fff;border:1px solid #cfd4dc;box-shadow:0 6px 20px rgba(0,0,0,.18);border-radius:10px;padding:6px;display:flex;flex-direction:column}.bb-ulmenu button{border:0;background:none;padding:7px 16px;font-weight:700;font-size:15px;cursor:pointer;border-radius:6px;color:#1f2933}.bb-ulmenu button:hover{background:#eef0f3}.bb-ulmenu .us{border-bottom:2px solid #1f2933;padding-bottom:1px}.bb-ulmenu .ud{border-bottom:2px dashed #1f2933;padding-bottom:1px}.bb-ulmenu .uo{border-bottom:2px dotted #1f2933;padding-bottom:1px}
mjx-container.hl{cursor:pointer}mjx-container.c-yellow{background:#ffe9a8}mjx-container.c-blue{background:#d6ebff}mjx-container.c-pink{background:#ffd6ec}mjx-container.c-yellow:hover{background:#ffd34d}mjx-container.c-blue:hover{background:#9ccbff}mjx-container.c-pink:hover{background:#ff9fd1}mjx-container.u{border-bottom:2px solid #333}mjx-container.u-dashed{border-bottom-style:dashed}mjx-container.u-dotted{border-bottom-style:dotted}

/* Practice runtime */
.bb-practice-main{min-height:0;overflow:auto;background:#fff}.bb-question{max-width:900px;margin:0 auto;padding:48px 44px 100px;font-family:var(--bb-serif)}
.bb-qhead{display:flex;align-items:stretch;background:#f0f0f0;border-bottom:2px dashed #20242a;margin-bottom:24px}.bb-qnum{background:#191b1e;color:#fff;padding:10px 14px;font:800 18px var(--bb-ui)}.bb-qmark{border:0;background:transparent;padding:0 15px;font:600 14px var(--bb-ui)}
.bb-prompt{font-size:18px;line-height:1.7;margin-bottom:24px}.bb-choice{width:100%;display:flex;align-items:center;gap:13px;border:1.8px solid #737a84;border-radius:9px;background:#fff;padding:13px 15px;margin:10px 0;text-align:left;font:400 16px/1.5 var(--bb-serif)}.bb-choice:hover{background:#eceeef}.bb-choice.selected{border-color:#3158d7;border-width:3px;padding:11.8px 13.8px}.bb-choice-letter{width:31px;height:31px;border:2px solid #69717c;border-radius:50%;display:flex;align-items:center;justify-content:center;font:700 13px var(--bb-ui);color:#69717c}.bb-choice.selected .bb-choice-letter{background:#3158d7;border-color:#3158d7;color:#fff}
.bb-fill{border:2px solid #727b86;border-radius:9px;padding:18px}.bb-fill label{display:block;font:700 13px var(--bb-ui);margin-bottom:9px}.bb-fill input{width:100%;border:2px solid #727b86;border-radius:6px;padding:12px;font:600 17px var(--bb-ui)}.bb-fill small{display:block;color:#687383;margin-top:8px;font:12px/1.45 var(--bb-ui)}
.bb-empty-practice{max-width:760px;margin:70px auto;border:1px solid #d8dde6;background:#fff;padding:34px}.bb-empty-practice h2{font:700 28px var(--bb-serif);margin:0 0 10px}.bb-empty-practice p{color:#606b79;line-height:1.65}
.bb-practice-figure{margin:18px auto 24px;width:min(330px,100%);border:1px solid #cfd5de;background:#f7f8fa;padding:14px;text-align:center}.bb-practice-figure.large{width:min(520px,100%)}.bb-practice-figure img{display:block;max-width:100%;height:auto;margin:auto}.bb-practice-review{max-width:920px;margin:0 auto;padding:40px 34px 95px}.bb-practice-review-head{border-left:5px solid #3158d7;background:#f3f6fb;padding:22px 24px;margin-bottom:20px}.bb-practice-review-head h2{font:700 30px var(--bb-serif);margin:4px 0}.bb-review-item{border:1px solid #d7dde5;background:#fff;margin:12px 0;padding:18px 20px}.bb-review-item.correct{border-left:5px solid #0f7d62}.bb-review-item.incorrect{border-left:5px solid #b54747}.bb-review-item h3{margin:0;font:700 17px var(--bb-serif)}.bb-review-item-head{display:flex;align-items:center;justify-content:space-between;gap:14px;margin:4px 0 7px}.bb-mistake-save{flex:0 0 auto;border:1.5px solid #284f43;border-radius:18px;background:#fff;color:#284f43;padding:6px 11px;font:700 11px/1 var(--bb-ui);white-space:nowrap;cursor:pointer}.bb-mistake-save:hover{background:#edf6f1}.bb-mistake-save.saved{background:#284f43;color:#fff}.bb-review-status{font:800 10px var(--bb-ui);letter-spacing:.08em;text-transform:uppercase}.bb-review-item.correct .bb-review-status{color:#0f7d62}.bb-review-item.incorrect .bb-review-status{color:#b54747}.bb-review-question{border:1px solid #dfe4eb;background:#fbfcfe;padding:16px 17px;margin:12px 0 14px}.bb-review-prompt{font:400 16px/1.7 var(--bb-serif);color:#1f2933;margin-bottom:12px}.bb-review-question .bb-practice-figure{margin:12px auto 16px}.bb-review-choices{display:grid;gap:8px}.bb-review-choice{display:grid;grid-template-columns:31px minmax(0,1fr) auto;align-items:center;gap:11px;border:1.5px solid #c4cad3;border-radius:7px;padding:9px 11px;background:#fff;font:400 14px/1.45 var(--bb-serif)}.bb-review-choice.correct-choice{border-color:#0f7d62;background:#eff8f4}.bb-review-choice.wrong-choice{border-color:#b54747;background:#fff4f4}.bb-review-choice.correct-choice .bb-choice-letter{background:#0f7d62;border-color:#0f7d62;color:#fff}.bb-review-choice.wrong-choice .bb-choice-letter{background:#b54747;border-color:#b54747;color:#fff}.bb-review-choice-badges{display:flex;flex-wrap:wrap;justify-content:flex-end;gap:5px;font:800 9px var(--bb-ui)}.bb-review-choice-badge{border-radius:999px;padding:4px 7px;white-space:nowrap}.bb-review-choice-badge.correct{background:#d7eee5;color:#075e49}.bb-review-choice-badge.student{background:#e3e9fb;color:#2847a9}.bb-review-answer{font:650 12px/1.6 var(--bb-ui);color:#44505e;margin:8px 0}.bb-student-answer{margin-bottom:3px}.bb-review-item.incorrect>.bb-review-answer>.bb-student-answer.single-answer,.bb-review-item.incorrect>.bb-review-answer>.bb-student-answer .bb-review-fields span.field-incorrect,.bb-review-item.incorrect>.bb-review-answer>.bb-student-answer .bb-review-fields span.field-incorrect>b{color:#b42318}.bb-review-item.incorrect>.bb-review-answer>.bb-student-answer .bb-review-fields span.field-correct,.bb-review-item.incorrect>.bb-review-answer>.bb-student-answer .bb-review-fields span.field-correct>b{color:#44505e}.bb-review-explanation{border-top:1px solid #e0e4e9;margin-top:10px;padding-top:10px;font:400 15px/1.7 var(--bb-serif)}.bb-review-actions{display:flex;justify-content:flex-end;flex-wrap:wrap;gap:10px;margin-top:22px}
.bb-practice-figure.full{width:min(860px,100%);padding:10px}.bb-practice-figure.tall{width:min(600px,100%)}
.bb-multi-fill{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:10px;border-top:1px solid #d7dce4;margin-top:20px;padding-top:20px}.bb-multi-fill label{display:flex;align-items:center;border:1px solid #c9d0da;background:#fff;min-height:42px}.bb-multi-fill label>span{align-self:stretch;min-width:40px;display:flex;align-items:center;justify-content:center;background:#1d232b;color:#fff;font:800 12px var(--bb-ui)}.bb-multi-fill input{width:100%;min-width:0;border:0;outline:0;padding:10px 9px;font:650 13px var(--bb-ui);background:#fff}.bb-multi-fill input:focus{box-shadow:inset 0 0 0 2px #3158d7}.bb-multi-fill>small{grid-column:1/-1;color:#687382;font:650 9px/1.5 var(--bb-ui)}
.bb-review-fields{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:5px;margin:6px 0 11px}.bb-review-fields span{display:flex;gap:7px;border:1px solid #d8dee7;background:#f7f9fb;padding:6px 8px;line-height:1.4}.bb-review-fields span>b{color:#3158d7}.bb-review-fields.correct-key span{background:#eff8f4;border-color:#cee3da}.bb-review-fields.correct-key span>b{color:#0f7d62}

@media(max-width:820px){.bb-hero{grid-template-columns:1fr}.bb-outline{display:none}.bb-notesbar{position:fixed;right:0;top:102px;bottom:75px;height:auto;z-index:96;box-shadow:-8px 0 25px rgba(0,0,0,.12)}.bb-page{padding:30px 20px 90px}.bb-tools{gap:8px}.bb-tool{min-width:47px}.bb-tool span:last-child{display:none}.bb-source-grid{grid-template-columns:1fr}.bb-test-top{padding-left:16px;padding-right:16px}.bb-section-title{font-size:16px}.bb-practice-review{padding:28px 16px 90px}.bb-review-question{padding:13px}.bb-review-choice{grid-template-columns:28px minmax(0,1fr)}.bb-review-choice-badges{grid-column:2;justify-content:flex-start}}

/* Authored Unit 1 textbook */
.bb-outline{width:278px;padding:21px 14px}
.bb-outline> b{margin-bottom:10px}
.bb-outline-tier{border-top:1px solid #d9dde4;padding:12px 0 7px}
.bb-outline-tier:first-child{border-top:0;padding-top:0}
.bb-outline-tier>span{display:block;padding:0 9px 7px;color:#7a627f;font:800 9px/1.35 var(--bb-ui);letter-spacing:.07em;text-transform:uppercase}
.bb-outline button{display:flex;align-items:flex-start;justify-content:space-between;gap:9px;padding:9px 10px}
.bb-outline button b{font:700 11px/1.35 var(--bb-ui);letter-spacing:0;text-transform:none;color:inherit;margin:0}
.bb-outline button small{font:700 9px/1.3 var(--bb-ui);color:#8b94a1;white-space:nowrap}
.bb-page{max-width:1040px;padding:42px 54px 110px}
.bb-page-head{border-bottom:0;background:linear-gradient(140deg,#f4f7fc 0,#fff 66%);padding:29px 30px 26px;margin:0 0 30px;border-left:5px solid #3158d7;box-shadow:0 12px 34px rgba(28,48,78,.07)}
.bb-page-head p{max-width:790px;font-size:14px}
.bb-page-meta{display:flex;justify-content:space-between;gap:20px;border-top:1px solid #dbe1ea;margin-top:17px;padding-top:13px;color:#667181;font:650 10px/1.5 var(--bb-ui)}
.bb-page-meta b{color:#3158d7;white-space:nowrap}
.bb-objectives{margin-top:18px;background:#fff;border:1px solid #dbe1ea;padding:16px 18px;font:600 12px/1.6 var(--bb-ui)}
.bb-objectives strong{color:#173650}.bb-objectives ul{margin:7px 0 0;padding-left:19px;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:5px 22px;color:#526070}
.bb-tier-group{scroll-margin-top:20px;margin:0 0 42px}
.bb-tier-banner{display:flex;gap:14px;align-items:center;padding:17px 20px;background:#171b21;color:#fff;border-radius:10px 10px 0 0}
.bb-tier-banner h2{margin:0;font:700 22px/1.2 var(--bb-serif)}
.bb-tier-banner p{margin:3px 0 0;color:#cdd3db;font:600 10px/1.4 var(--bb-ui)}
.bb-tier-banner .bb-tier-label{background:#fff;color:#171b21;white-space:nowrap}
.bb-study-block{scroll-margin-top:24px;border:1px solid #d5dbe4;border-top:0;background:#fff}
.bb-study-block+ .bb-study-block{border-top:12px solid #f2f4f7}
.bb-study-block>header{display:flex;align-items:center;gap:13px;padding:16px 20px;background:#f4f6f9;border-bottom:1px solid #d8dee7}
.bb-study-block>header>span{width:34px;height:34px;display:flex;align-items:center;justify-content:center;background:#3158d7;color:#fff;border-radius:50%;font:800 10px var(--bb-ui)}
.bb-study-block>header h2{margin:0;color:#172a3e;font:700 20px/1.3 var(--bb-serif)}
.bb-study-block>header small{font:650 9px var(--bb-ui);color:#7b8593;text-transform:uppercase;letter-spacing:.08em}
.bb-study-block .bb-tier-copy{padding:26px 29px 31px;color:#202831;font-size:16px;line-height:1.85}
.bb-section-checks{margin:0 29px 31px;border:1px solid #cdd7e5;border-radius:10px;overflow:hidden;background:#fff;font-family:var(--bb-ui)}
.bb-section-checks>header{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:16px 18px;background:#edf3ff;border-bottom:1px solid #d4deee}
.bb-section-checks>header span{display:block;color:#3158d7;font:800 9px/1 var(--bb-ui);letter-spacing:.13em;text-transform:uppercase}
.bb-section-checks>header h3{margin:5px 0 0;color:#172a3e;font:800 18px/1.2 var(--bb-ui)}
.bb-section-checks>header>b{color:#42516a;font:750 11px/1.2 var(--bb-ui);white-space:nowrap}
.bb-section-check-intro{margin:0;padding:12px 18px;color:#667287;background:#f8faff;border-bottom:1px solid #e0e6ef;font:600 11px/1.55 var(--bb-ui)}
.bb-section-check-list{display:grid}
.bb-section-check-item{display:grid;grid-template-columns:32px 1fr;gap:13px;padding:18px;border-bottom:1px solid #e1e6ee;background:#fff}
.bb-section-check-number{width:29px;height:29px;display:flex;align-items:center;justify-content:center;border-radius:50%;background:#1e2f46;color:#fff;font:800 11px var(--bb-ui)}
.bb-section-check-body>p{margin:2px 0 12px;color:#202b38;font:650 14px/1.6 var(--bb-ui)}
.bb-section-options{display:grid;gap:8px}
.bb-section-options button{display:flex;align-items:flex-start;gap:10px;width:100%;padding:10px 12px;border:1.5px solid #aeb8c6;border-radius:7px;background:#fff;color:#2f3947;text-align:left;font:600 12px/1.45 var(--bb-ui);cursor:pointer}
.bb-section-options button:hover{background:#f2f4f7}.bb-section-options button>span{flex:0 0 23px;height:23px;display:flex;align-items:center;justify-content:center;border:2px solid #7d8794;border-radius:50%;color:#5d6672;font:800 10px var(--bb-ui)}
.bb-section-options button.selected{border-color:#3158d7;background:#f2f6ff}.bb-section-options button.selected>span{border-color:#3158d7;background:#3158d7;color:#fff}
.bb-section-options button.correct-option{border-color:#278358;background:#effaf4}.bb-section-options button.correct-option>span{border-color:#278358;background:#278358;color:#fff}
.bb-section-options button.wrong-option{border-color:#bb3d45;background:#fff3f3}.bb-section-options button.wrong-option>span{border-color:#bb3d45;background:#bb3d45;color:#fff}
.bb-section-fill-row{display:flex;gap:8px}.bb-section-fill-row input{min-width:0;flex:1;padding:10px 12px;border:1.5px solid #aeb8c6;border-radius:7px;color:#1f2933;background:#fff;font:650 13px var(--bb-ui)}
.bb-section-fill-row input:focus{outline:2px solid #adc3ff;outline-offset:1px;border-color:#3158d7}.bb-section-fill-row button{padding:0 16px;border:1.5px solid #1e2f46;border-radius:7px;background:#1e2f46;color:#fff;font:750 11px var(--bb-ui);cursor:pointer}
.bb-section-check-item.is-correct .bb-section-fill-row input{border-color:#278358;background:#effaf4}.bb-section-check-item.is-incorrect .bb-section-fill-row input{border-color:#bb3d45;background:#fff3f3}
.bb-section-check-feedback{display:none;margin-top:10px;padding:10px 12px;border-radius:7px;font:600 11px/1.55 var(--bb-ui)}.bb-section-check-item.is-checked .bb-section-check-feedback{display:flex;gap:8px;align-items:flex-start}
.bb-section-check-item.is-correct .bb-section-check-feedback{background:#eaf7f0;color:#206847}.bb-section-check-item.is-incorrect .bb-section-check-feedback{background:#fff0f0;color:#8e3037}.bb-section-check-feedback>b{white-space:nowrap}.bb-section-check-feedback span{color:inherit}
.bb-section-checks>footer{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:12px 18px;background:#f4f6f9}.bb-section-checks>footer output{color:#1e2f46;font:800 12px var(--bb-ui)}.bb-section-checks>footer span{color:#7a8492;font:600 10px var(--bb-ui)}
.bb-section-page-head{margin-bottom:20px}.bb-section-page-head .bb-page-meta b{font-variant-numeric:tabular-nums}
.bb-single-section{margin-bottom:26px}.bb-single-section .bb-study-block{border-radius:0 0 10px 10px;overflow:hidden}
.bb-finish-dialog .bb-confirm-time{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px;margin:18px 0}.bb-confirm-time span{border:1px solid #d8dde6;background:#f7f9fc;border-radius:8px;padding:13px;color:#657083;font:700 11px var(--bb-ui)}.bb-confirm-time b{display:block;margin-top:5px;color:#172a3e;font:800 22px var(--bb-ui);font-variant-numeric:tabular-nums}
.bb-study-complete{max-width:760px;margin:0 auto;padding:58px 34px 90px}.bb-study-complete h1{font:700 38px/1.15 var(--bb-serif);margin:10px 0}.bb-study-complete>p{color:#657083;font:600 13px/1.65 var(--bb-ui)}
.bb-time-summary{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;margin:28px 0}.bb-time-summary article{border:1px solid #d7dde6;border-top:5px solid #3158d7;background:#f8fafc;padding:18px}.bb-time-summary span{display:block;color:#667181;font:750 10px var(--bb-ui)}.bb-time-summary b{display:block;margin-top:7px;color:#172a3e;font:800 30px var(--bb-ui);font-variant-numeric:tabular-nums}
.bb-section-time-list{border:1px solid #d7dde6;border-radius:9px;overflow:hidden;margin-bottom:24px}.bb-section-time-list>div{display:grid;grid-template-columns:minmax(0,1fr) auto auto;align-items:center;gap:18px;padding:13px 16px;border-top:1px solid #e1e5eb;font:700 11px/1.4 var(--bb-ui)}.bb-section-time-list>div:first-child{border-top:0}.bb-section-time-list span{color:#273442}.bb-section-time-list b{color:#6b7582}.bb-section-time-list em{min-width:82px;color:#3158d7;font-style:normal;font-variant-numeric:tabular-nums;text-align:right}
.bb-tier-copy h3{font:700 19px/1.35 var(--bb-serif);color:#18344e;margin:25px 0 9px}
.bb-tier-copy h3:first-child{margin-top:0}
.bb-tier-copy p{margin:0 0 15px}
.bb-tier-copy ul,.bb-tier-copy ol{margin:8px 0 16px;padding-left:23px}.bb-tier-copy li{margin:4px 0}
.bb-lead{font-size:19px!important;line-height:1.72!important;color:#162c40;font-weight:600!important}
.bb-equation{text-align:center;background:#f6f8fb;border:1px solid #dbe1e8;padding:16px;margin:14px 0 18px;font-size:21px}
.bb-causal-chain,.bb-pet-chain{display:flex;align-items:stretch;gap:7px;margin:20px 0;overflow-x:auto;padding-bottom:3px}
.bb-causal-chain span,.bb-pet-chain span{min-width:125px;flex:1;background:#edf3ff;border:1px solid #c7d5f1;padding:12px 10px;text-align:center;font:750 11px/1.45 var(--bb-ui);color:#244385}
.bb-causal-chain b,.bb-pet-chain b{align-self:center;color:#788391;font-family:var(--bb-ui)}
.bb-pet-chain span{background:#f3effa;border-color:#d9cceb;color:#5f397c}
.bb-callout{margin:19px 0;padding:16px 18px 16px 49px;border:1px solid #d9dfe7;background:#f8fafc;position:relative;font-size:14px;line-height:1.7}
.bb-callout::before{position:absolute;left:16px;top:14px;width:23px;height:23px;border-radius:50%;display:flex;align-items:center;justify-content:center;font:800 11px var(--bb-ui)}
.bb-callout>b{display:block;margin-bottom:4px;color:#172d43;font-family:var(--bb-ui);font-size:12px;letter-spacing:.02em}
.bb-callout ul,.bb-callout ol{margin:4px 0 0}
.bb-callout.concept{background:#f0f7f5;border-color:#cfe2dc}.bb-callout.concept::before{content:"C";background:#0f7d62;color:#fff}
.bb-callout.why{background:#f0f4ff;border-color:#cbd8f8}.bb-callout.why::before{content:"?";background:#3158d7;color:#fff}
.bb-callout.trap{background:#fff8ed;border-color:#ebd5b2}.bb-callout.trap::before{content:"!";background:#bd7422;color:#fff}
.bb-callout.correction{background:#fff1f1;border-color:#efc8c8}.bb-callout.correction::before{content:"✓";background:#9f3f3f;color:#fff}
.bb-callout.exam-lock{background:#f5f2fb;border-color:#d9ccec}.bb-callout.exam-lock::before{content:"B";background:#654087;color:#fff}
.bb-callout.frontier{background:#eef6ff;border-color:#c4d9ef}.bb-callout.frontier::before{content:"R";background:#24618e;color:#fff}
.bb-callout.reader{background:#f5f0ff;border-color:#d9cbea}.bb-callout.reader::before{content:"读";background:#654087;color:#fff;font-size:9px}
.bb-callout.precision{background:#eef6ff;border-color:#c6dced}.bb-callout.precision::before{content:"准";background:#24618e;color:#fff;font-size:9px}
.bb-reader-note{margin:.2rem 0 1rem;padding:.72rem .9rem;border-left:3px solid #2f6a57;background:#f4f8f6;color:#33483f;font-size:.96rem;line-height:1.65}
.bb-definition{box-decoration-break:clone;-webkit-box-decoration-break:clone}
.bb-definition.bb-term-line{display:block;margin:0 0 8px;padding:0 0 8px;border-bottom:1px solid #e9edf2}
.bb-definition.bb-term-line:last-child{margin-bottom:0}
.bb-definition dfn{font-style:normal;font-weight:800;color:#173f67;border-bottom:1px dotted #6d86a2}
.bb-definition>span{color:#313d4a}
.bb-chapter-orientation,.bb-chapter-synthesis{border:1px solid #cbd7e4;background:linear-gradient(180deg,#f8fbff,#fff);padding:20px;margin:0 0 18px}
.bb-chapter-orientation>h3,.bb-chapter-synthesis>h3{margin:0 0 9px;color:#122f4a}
.bb-chapter-purpose{font:700 18px/1.65 var(--bb-serif);color:#1b2f42;margin:0 0 15px}
.bb-chapter-aha{border-left:5px solid #3158d7;background:#edf3ff;padding:16px 18px;margin:18px 0;font:600 16px/1.75 var(--bb-serif);color:#1c3046}
.bb-chapter-aha b{display:block;margin-bottom:5px;color:#173e73;font:800 12px/1.3 var(--bb-ui);letter-spacing:.08em;text-transform:uppercase}
.bb-mechanism-steps{counter-reset:mechanism;display:grid;gap:8px;margin:15px 0}
.bb-mechanism-steps>article{counter-increment:mechanism;display:grid;grid-template-columns:32px 1fr;gap:10px;align-items:start;border:1px solid #dde4ec;background:#fff;padding:12px 14px}
.bb-mechanism-steps>article:before{content:counter(mechanism);width:28px;height:28px;display:flex;align-items:center;justify-content:center;background:#172a3e;color:#fff;border-radius:50%;font:800 11px var(--bb-ui)}
.bb-mechanism-steps h4{margin:1px 0 4px;font:800 15px/1.3 var(--bb-ui);color:#173f67}.bb-mechanism-steps p{margin:0;font-size:15px;line-height:1.65}
.bb-method-preview,.bb-structure-key{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px;margin:16px 0 20px}
.bb-method-preview article,.bb-structure-key article{border:1px solid #d7dee7;background:#fafbfc;padding:13px 14px}
.bb-method-preview b,.bb-structure-key b{display:block;color:#173650;font:800 11px/1.45 var(--bb-ui);margin-bottom:4px}
.bb-method-preview p{margin:0!important;color:#576474;font:600 10px/1.55 var(--bb-ui)!important}
.bb-structure-key span{display:block;color:#576474;font:600 10px/1.55 var(--bb-ui)}
.bb-two-col{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;margin:17px 0}.bb-two-col>div{border:1px solid #dce1e8;background:#fafbfc;padding:16px 17px}.bb-two-col h3{margin:0 0 7px}.bb-two-col .bb-callout{margin:0}
.bb-numbered{counter-reset:item;list-style:none;padding:0!important}.bb-numbered li{counter-increment:item;position:relative;padding:8px 11px 8px 44px;margin:0!important;border-bottom:1px solid #e4e7ec}.bb-numbered li::before{content:counter(item);position:absolute;left:8px;top:7px;width:25px;height:25px;border-radius:50%;background:#1d3f5f;color:#fff;display:flex;align-items:center;justify-content:center;font:800 10px var(--bb-ui)}
.bb-sources{display:flex;flex-wrap:wrap;gap:7px;margin:18px 0 4px}
.bb-source-link{display:inline-flex;gap:7px;align-items:center;border:1px solid #c9d2de;background:#fff;border-radius:999px;padding:7px 11px;color:#3158d7;text-decoration:none;font:700 9px/1.2 var(--bb-ui)}.bb-source-link:hover{text-decoration:underline;background:#f0f4ff}
.bb-source-figure{margin:22px 0;border:1px solid #cad2dc;background:#fff;box-shadow:0 10px 28px rgba(20,35,52,.08)}.bb-source-figure img{display:block;width:100%;height:auto;max-height:720px;object-fit:contain;background:#fff}.bb-source-figure.portrait img{max-height:820px}.bb-source-figure figcaption{border-top:1px solid #d7dde5;background:#f6f8fa;padding:10px 13px;font:650 9px/1.55 var(--bb-ui);color:#5e6977}.bb-source-figure figcaption b{color:#1f3e59}.bb-source-figure .bb-figure-purpose{display:block;margin-top:3px;color:#3158d7;font-weight:750}
.bb-readout-lab{border:1px solid #cfd7e1;background:#f8fafc;border-radius:8px;padding:17px;margin:18px 0;font-family:var(--bb-ui)}.bb-readout-lab h3{margin:0 0 11px}.bb-readout-buttons{display:flex;flex-wrap:wrap;gap:7px}.bb-readout-buttons button{border:1px solid #aeb8c5;background:#fff;border-radius:999px;padding:7px 11px;color:#33404d;font:750 9px var(--bb-ui)}.bb-readout-buttons button:hover,.bb-readout-buttons button.active{background:#3158d7;border-color:#3158d7;color:#fff}.bb-readout-lab output{display:block;min-height:54px;margin-top:12px;border-left:4px solid #3158d7;background:#fff;padding:11px 13px;color:#374451;font:600 11px/1.6 var(--bb-ui)}
.bb-hierarchy{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:8px;margin:17px 0}.bb-hierarchy article{border:1px solid #d4dbe4;background:#fff;padding:12px}.bb-hierarchy article.root{background:#172a3e;color:#fff;grid-column:1/-1}.bb-hierarchy article b{display:block;font:800 11px/1.4 var(--bb-ui)}.bb-hierarchy article span{display:block;margin-top:4px;color:#687483;font:600 9px/1.5 var(--bb-ui)}.bb-hierarchy article.root span{color:#d4dce5}
.bb-memory-rule{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:9px;margin:16px 0}.bb-memory-rule article{border-top:5px solid #3158d7;background:#f4f7fb;padding:13px}.bb-memory-rule b{display:block;color:#173650;font:800 11px var(--bb-ui)}.bb-memory-rule span{display:block;margin-top:4px;color:#596675;font:600 9px/1.55 var(--bb-ui)}

/* Unit 3: neuron mechanisms. These explain relationships; source figures carry anatomy. */
.bb-cell-factory{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:8px;margin:18px 0;font-family:var(--bb-ui)}
.bb-cell-factory article{position:relative;min-height:118px;border:1px solid #d4dce6;background:linear-gradient(155deg,#fff,#f1f5fa);padding:39px 12px 12px}
.bb-cell-factory article:not(:last-child)::after{content:"→";position:absolute;right:-13px;top:47px;z-index:2;color:#3158d7;font:900 18px/1 var(--bb-ui)}
.bb-cell-factory span{position:absolute;left:11px;top:10px;width:21px;height:21px;border-radius:50%;display:flex;align-items:center;justify-content:center;background:#3158d7;color:#fff;font:800 9px var(--bb-ui)}
.bb-cell-factory b{display:block;color:#173650;font:800 10px/1.4 var(--bb-ui)}
.bb-cell-factory p{margin:6px 0 0!important;color:#5c6876;font:600 9px/1.5 var(--bb-ui)!important}
.bb-transport-lab{margin:19px 0;border:1px solid #cfd8e4;background:#f7f9fc;padding:17px 18px 14px;overflow:hidden;font-family:var(--bb-ui)}
.bb-transport-labels{display:flex;justify-content:space-between;gap:20px;color:#1b344d;font:800 10px/1.3 var(--bb-ui);margin-bottom:9px}
.bb-transport-track{height:42px;position:relative;margin:8px 0;border-radius:6px;background:repeating-linear-gradient(90deg,#6e7c8d 0 13px,#a9b4c2 13px 18px);box-shadow:inset 0 0 0 14px #edf1f6}
.bb-transport-track::before,.bb-transport-track::after{position:absolute;top:50%;transform:translateY(-50%);z-index:1;color:#657180;font:900 14px var(--bb-ui)}
.bb-transport-track.forward::before{content:"胞体";left:8px}.bb-transport-track.forward::after{content:"终末";right:8px}
.bb-transport-track.reverse::before{content:"胞体";left:8px}.bb-transport-track.reverse::after{content:"终末";right:8px}
.bb-transport-track span{position:absolute;top:7px;left:58px;z-index:2;min-width:72px;padding:6px 8px;border-radius:999px;background:#3158d7;color:#fff;text-align:center;font:800 8px/1.2 var(--bb-ui);box-shadow:0 4px 12px rgba(49,88,215,.25);animation:bbCargoForward 4.2s linear infinite}
.bb-transport-track.reverse span{background:#9a5d27;animation-name:bbCargoReverse}
.bb-transport-lab>p{margin:11px 0 0!important;color:#5d6976;font:600 9px/1.55 var(--bb-ui)!important}
@keyframes bbCargoForward{0%{left:58px}100%{left:calc(100% - 140px)}}
@keyframes bbCargoReverse{0%{left:calc(100% - 140px)}100%{left:58px}}
@media(prefers-reduced-motion:reduce){.bb-transport-track span{animation:none}.bb-transport-track.forward span{left:calc(72% - 36px)}.bb-transport-track.reverse span{left:calc(28% - 36px)}}

/* Anatomical planes */
.bb-plane-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin:17px 0}.bb-plane-grid article{border:1px solid #d8dee7;background:#fafbfc;padding:14px;text-align:center;font-family:var(--bb-ui)}.bb-plane-grid b,.bb-plane-grid span{display:block}.bb-plane-grid b{font-size:12px}.bb-plane-grid span{color:#697484;font-size:9px;margin-top:3px}.bb-plane-icon{width:72px;height:72px;border:2px solid #8894a2;border-radius:45% 52% 48% 43%;margin:0 auto 10px;position:relative;background:#edf1f6}.bb-plane-icon::after{content:"";position:absolute;background:#3158d7}.bb-plane-icon.sagittal::after{width:3px;top:-4px;bottom:-4px;left:50%}.bb-plane-icon.coronal::after{height:3px;left:-5px;right:-5px;top:46%}.bb-plane-icon.axial::after{height:3px;left:-5px;right:-5px;top:67%;transform:rotate(-8deg)}

/* Interactives */
.bb-interactive{border:1px solid #c9d1dc;background:#f8fafc;border-radius:9px;padding:18px;margin:20px 0;font-family:var(--bb-ui)}
.bb-interactive p{font:550 11px/1.6 var(--bb-ui);color:#5f6977;margin:12px 0 0}
.bb-interactive-head{display:flex;justify-content:space-between;gap:16px;align-items:flex-start}.bb-interactive-head h3{font-family:var(--bb-serif);margin:4px 0 0}.bb-interactive-head output,.bb-interactive-head>span{background:#171b21;color:#fff;border-radius:999px;padding:6px 10px;font:750 9px var(--bb-ui);white-space:nowrap}
.bb-ct-svg{display:block;width:min(410px,100%);height:auto;margin:6px auto}.bb-slider-label{display:flex;align-items:center;gap:14px;font:750 10px var(--bb-ui);color:#4e5967}.bb-slider-label input{flex:1;accent-color:#3158d7}
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/* Cases, tables, recall and evidence */
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.bb-evidence-ladder{display:grid;grid-template-columns:repeat(4,1fr);gap:6px;margin:18px 0}.bb-evidence-ladder article{border-top:5px solid #9aa5b2;background:#f5f7f9;padding:13px}.bb-evidence-ladder article.current{border-color:#3158d7;background:#eef3ff}.bb-evidence-ladder span{font:800 9px var(--bb-ui);color:#3158d7;text-transform:uppercase}.bb-evidence-ladder p{font-size:11px;line-height:1.55;margin:6px 0 0}
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@media(max-width:980px){.bb-objectives ul{grid-template-columns:1fr}.bb-evidence-ladder{grid-template-columns:repeat(2,1fr)}}
@media(max-width:980px){.bb-cell-factory{grid-template-columns:repeat(2,minmax(0,1fr))}.bb-cell-factory article::after{display:none}}
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@media(max-width:820px){.bb-multi-fill,.bb-review-fields,.bb-hierarchy,.bb-memory-rule{grid-template-columns:1fr}}

/* Unit 4: neurotransmitter mechanisms. Textbook figures carry morphology; these components model logic only. */
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