:root{color-scheme:light;--ink:#17233a;--muted:#627086;--soft:#8c98a9;--line:#e2e7ef;--bg:#f4f6fb;--paper:#fff;--blue:#3769d6;--blue-dark:#2453ba;--blue-soft:#edf2ff;--mint:#dff7ed;--green:#176c4f;--red:#a53e3e;--gold:#fff3d4;--shadow:0 10px 34px rgba(24,43,77,.07)}
*{box-sizing:border-box}
html{min-width:320px;scroll-behavior:smooth;scroll-padding-top:24px}
body{margin:0;background:var(--bg);color:var(--ink);font-family:Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",sans-serif;font-size:16px;line-height:1.55}
a{color:inherit}
button,input,select{font:inherit}
button{cursor:pointer}
.skip-link{position:absolute;left:12px;top:-60px;z-index:10;padding:10px 14px;border-radius:8px;background:var(--ink);color:#fff}
.skip-link:focus{top:12px}
.topbar{height:70px;display:flex;align-items:center;justify-content:space-between;padding:0 max(24px,calc((100vw - 1240px)/2));background:#fff;border-bottom:1px solid var(--line)}
.math-brand{display:flex;align-items:center;gap:11px;text-decoration:none;font-weight:800;letter-spacing:-.02em}
.brand-icon{display:grid;place-items:center;width:36px;height:36px;border-radius:11px;background:var(--blue);color:#fff;font-size:1.35rem}
.top-links{display:flex;align-items:center;gap:22px;color:var(--muted);font-size:.9rem;font-weight:650}
.top-links a{text-decoration:none}
.top-links a:hover,.page-footer a:hover{color:var(--blue)}
.layout{display:grid;grid-template-columns:235px minmax(0,1fr);gap:36px;width:min(1240px,calc(100% - 48px));margin:32px auto 64px;align-items:start}
.sidebar{position:sticky;top:22px}
.progress-card,.formula-card{padding:18px;border:1px solid var(--line);border-radius:16px;background:var(--paper);box-shadow:var(--shadow)}
.progress-heading,.score-line{display:flex;align-items:center;justify-content:space-between}
.progress-heading{font-size:.68rem;font-weight:850;letter-spacing:.1em;color:var(--muted)}
.progress-heading span:last-child{font-size:.9rem;letter-spacing:0;color:var(--blue)}
.progress-track{height:8px;margin-top:13px;border-radius:99px;background:#e8edf5;overflow:hidden}
.progress-track span{display:block;width:0;height:100%;border-radius:inherit;background:linear-gradient(90deg,#70d1ad,#3769d6);transition:width .25s ease}
.progress-card>p{margin:9px 0 14px;color:var(--muted);font-size:.76rem}
.score-line{padding-top:12px;border-top:1px solid var(--line);font-size:.8rem;color:var(--muted)}
.score-line strong{color:var(--ink)}
.lesson-nav{display:flex;flex-direction:column;gap:3px;margin:24px 0}
.nav-label{margin:0 0 7px 10px;color:var(--soft);font-size:.65rem;font-weight:850;letter-spacing:.12em}
.lesson-nav>a{display:flex;align-items:center;gap:10px;padding:9px 10px;border-radius:9px;color:#4d5b70;text-decoration:none;font-size:.82rem;font-weight:650}
.lesson-nav>a:hover{background:#e9eef8;color:var(--blue)}
.lesson-nav>a>span:first-child{width:23px;color:#8a97a9;font-size:.67rem;font-weight:800}
.lesson-nav .nav-practice,.lesson-nav .nav-test{justify-content:space-between;margin-top:8px;background:var(--blue-soft);color:var(--blue)}
.lesson-nav .nav-test{margin-top:3px;background:#eaf7f2;color:var(--green)}
.formula-card{padding:17px;background:#17233a;color:#fff}
.formula-label{display:block;color:#a9bddf;font-size:.64rem;font-weight:850;letter-spacing:.11em}
.formula-card strong{display:block;margin:9px 0 7px;color:#fff;font-size:1.55rem;letter-spacing:.04em}
.formula-card p{margin:0;color:#cad5e6;font-size:.76rem;line-height:1.55}
.formula-card b{color:#a8c5ff}
.content{min-width:0}
.welcome{position:relative;overflow:hidden;padding:46px 48px 32px;border:1px solid #dfe5f1;border-radius:22px;background:radial-gradient(circle at 95% 5%,rgba(95,134,220,.18),transparent 36%),linear-gradient(135deg,#fff 0%,#f5f8ff 100%);box-shadow:var(--shadow)}
.welcome:after{position:absolute;right:45px;top:33px;width:115px;height:115px;border:1px solid rgba(55,105,214,.12);border-radius:50%;content:"";box-shadow:0 0 0 15px rgba(55,105,214,.035),0 0 0 31px rgba(55,105,214,.025)}
.eyebrow{margin:0 0 8px;color:var(--blue);font-size:.68rem;font-weight:850;letter-spacing:.13em}
.welcome h1{position:relative;z-index:1;margin:0;font-size:clamp(2.3rem,5vw,3.7rem);line-height:1.04;letter-spacing:-.06em}
.welcome h1 span{color:var(--blue)}
.welcome>p:not(.eyebrow){max-width:540px;margin:15px 0 20px;color:var(--muted);font-size:1rem}
.primary-button,.quiet-button{display:inline-flex;align-items:center;justify-content:center;gap:9px;min-height:43px;padding:10px 15px;border:0;border-radius:10px;background:var(--blue);color:#fff;text-decoration:none;font-size:.84rem;font-weight:800;box-shadow:0 4px 10px rgba(55,105,214,.16);transition:background .15s,transform .15s}
.primary-button:hover{background:var(--blue-dark);transform:translateY(-1px)}
.primary-button:focus-visible,.quiet-button:focus-visible,.text-button:focus-visible,.choice:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid #8ab0ff;outline-offset:2px}
.welcome-stats{display:flex;align-items:center;gap:15px;margin-top:25px;padding-top:19px;border-top:1px solid var(--line);color:var(--muted);font-size:.75rem}
.welcome-stats b{color:var(--ink)}
.welcome-stats i{width:4px;height:4px;border-radius:50%;background:#aeb8c7}
.concept-strip{display:flex;align-items:center;gap:15px;margin:18px 0 46px;padding:17px 20px;border:1px solid #cfe9dd;border-radius:14px;background:#f0faf5}
.concept-icon{display:grid;flex:none;place-items:center;width:40px;height:40px;border-radius:12px;background:#d9f3e6;color:var(--green);font-size:1.4rem;font-weight:800}
.concept-strip strong{font-size:.88rem}
.concept-strip p{margin:3px 0 0;color:var(--muted);font-size:.76rem}
.equation-chip{margin-left:auto;padding:7px 10px;border-radius:8px;background:#fff;color:var(--green);font-weight:800;white-space:nowrap}
.lesson{padding:0 0 36px;margin:0 0 36px;border-bottom:1px solid var(--line);scroll-margin-top:25px}
.lesson-kicker{display:flex;gap:12px;margin-bottom:9px;color:var(--blue);font-size:.64rem;font-weight:850;letter-spacing:.11em}
.lesson-kicker span+span{color:#94a0b1}
h2{margin:0;font-size:clamp(1.55rem,3vw,2.05rem);line-height:1.2;letter-spacing:-.04em}
.lesson-lead{max-width:720px;margin:10px 0 22px;color:var(--muted);font-size:.95rem}
.two-col{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;margin:14px 0}
.mini-card,.wide-card,.graph-card{border:1px solid var(--line);border-radius:15px;background:var(--paper);box-shadow:var(--shadow)}
.mini-card{padding:19px}
.mini-card h3,.wide-card h3,.graph-card h3{margin:0 0 9px;font-size:1rem;letter-spacing:-.02em}
.mini-card>p,.wide-card p,.graph-card p{margin:8px 0;color:var(--muted);font-size:.84rem;line-height:1.65}
.formula-box{margin:12px 0;padding:13px 14px;border:1px solid #dfe7fb;border-radius:10px;background:#f2f6ff;color:#254f9c;text-align:center;font-size:1.1rem;font-weight:850;letter-spacing:.015em}
.small-formula{font-size:.9rem;line-height:1.8}
.worked{margin-top:14px;padding:12px 13px;border-left:3px solid #87cfae;border-radius:0 9px 9px 0;background:#f2faf6}
.worked-label{display:block;color:#35735a;font-size:.61rem;font-weight:900;letter-spacing:.1em}
.worked p{margin:5px 0 0;color:#34475e;font-size:.8rem;line-height:1.6}
.worked p+p{margin-top:7px}
.muted{color:var(--muted)!important}
.steps{padding-left:20px;color:#526178;font-size:.81rem}
.steps li{padding:3px 0}
.wide-card{display:grid;grid-template-columns:1.1fr .9fr;gap:18px;padding:19px}
.slope-types{display:grid;grid-template-columns:1fr 1fr;gap:9px;align-content:center}
.slope-types>div{display:grid;grid-template-columns:34px 1fr;column-gap:7px;align-items:center;padding:10px 9px;border-radius:10px;background:#f6f8fc}
.slope-types b{font-size:.76rem}.slope-types small{grid-column:2;color:var(--muted);font-size:.66rem}
.type-line{grid-row:span 2;display:block;width:30px;height:22px;position:relative;overflow:hidden}
.type-line:after{position:absolute;left:1px;top:10px;width:39px;height:3px;border-radius:4px;background:var(--blue);content:""}
.type-line.positive:after{transform:rotate(-35deg)}
.type-line.negative:after{transform:rotate(35deg)}
.type-line.zero:after{transform:rotate(0)}
.type-line.undefined:after{left:13px;top:-2px;width:3px;height:28px}
.text-button{display:inline-flex;align-items:center;gap:7px;margin:10px 10px 0 0;padding:5px 0;border:0;background:none;color:var(--blue);font-size:.82rem;font-weight:850}
.text-button:hover{text-decoration:underline}
.secondary-practice{color:#5a6d86}
.relation-icon{float:right;display:grid;place-items:center;width:35px;height:35px;border-radius:11px;background:#eff3ff;color:var(--blue);font-size:1.4rem;font-weight:850}
.perp-icon{background:#f3efff;color:#7454b5}
.symbol-list{margin:12px 0}
.symbol-list p{display:flex;align-items:center;gap:10px;margin:6px 0;padding:7px 9px;border-radius:7px;background:#f7f8fc;font-size:.79rem}
.symbol-list b{min-width:20px;color:var(--blue);font-size:1rem}
.symbol-list span{margin-left:auto;color:var(--muted);font-size:.69rem;text-align:right}
.graph-card{display:grid;grid-template-columns:.85fr 1.15fr;gap:15px;align-items:center;margin:16px 0;padding:18px}
.graph-copy h3{margin-top:6px}
.graph-controls{display:flex;flex-wrap:wrap;gap:9px;margin-top:14px}
.graph-controls label{display:flex;align-items:center;gap:6px;color:var(--muted);font-size:.72rem}
.graph-controls input{width:67px;padding:7px 8px;border:1px solid var(--line);border-radius:8px;background:#fff;color:var(--ink)}
.graph-controls strong{align-self:center;margin-left:auto;padding:6px 9px;border-radius:8px;background:var(--blue-soft);color:var(--blue);font-size:.83rem}
.graph-frame{min-width:0;padding:7px;border:1px solid #e6eaf1;border-radius:12px;background:#fbfcff}
.graph-frame svg,.question-graph svg{display:block;width:100%;height:auto}
.practice-section,.test-section{margin:48px 0;scroll-margin-top:24px}
.section-heading{display:flex;align-items:center;justify-content:space-between;gap:18px;margin-bottom:18px}
.section-heading>div:first-child{max-width:640px}
.section-heading p:not(.eyebrow){margin:8px 0 0;color:var(--muted);font-size:.88rem}
.practice-badge,.test-badge{display:grid;flex:none;place-items:center;width:52px;height:52px;border-radius:17px;background:#e6f4ed;color:var(--green);font-size:1.5rem;font-weight:850}
.test-badge{background:#fff1d4;color:#916813}
.practice-panel{padding:21px;border:1px solid var(--line);border-radius:17px;background:#fff;box-shadow:var(--shadow)}
.practice-toolbar{display:flex;align-items:end;justify-content:space-between;gap:12px;padding-bottom:17px;border-bottom:1px solid var(--line)}
.practice-toolbar label,.written-form label{display:flex;flex-direction:column;gap:6px;color:var(--muted);font-size:.72rem;font-weight:750}
select,.written-form input{max-width:100%;min-width:210px;padding:9px 11px;border:1px solid #d6deea;border-radius:9px;background:#fff;color:var(--ink);font-size:.82rem}
.quiet-button{min-height:38px;padding:8px 12px;border:1px solid var(--line);background:#fff;color:#4e5d72;box-shadow:none}
.quiet-button:hover{background:#f4f6fa}
.question-meta{display:flex;align-items:center;justify-content:space-between;gap:10px;margin:16px 0 8px;color:var(--soft);font-size:.66rem;font-weight:850;letter-spacing:.08em}
.question-meta span+span{font-weight:600;letter-spacing:0;text-align:right}
.answer-modes{display:flex;gap:7px;margin:0 0 11px}
.answer-modes button{padding:6px 10px;border:1px solid var(--line);border-radius:8px;background:#fff;color:var(--muted);font-size:.71rem;font-weight:750}
.answer-modes button[aria-pressed=true]{border-color:#b8caee;background:var(--blue-soft);color:var(--blue)}
.question-card{min-height:158px;padding:19px;border-radius:13px;background:#f7f9fd}
.question-prompt{margin:0 0 13px;font-size:1.05rem;font-weight:750;line-height:1.5}
.question-table{border-collapse:collapse;margin:8px auto 0;background:#fff;text-align:center}
.question-table th,.question-table td{min-width:52px;padding:7px 11px;border:1px solid #dce3ef}
.question-table th{background:#edf2ff;color:#315cb5;font-size:.75rem}
.question-table td{font-size:.85rem}
.question-graph{max-width:360px;margin:12px auto 0;padding:5px;border:1px solid #e1e7f0;border-radius:10px;background:#fff}
.choice-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:9px}
.choice{display:flex;align-items:center;gap:10px;min-height:46px;padding:9px 11px;border:1px solid #dce3ed;border-radius:10px;background:#fff;color:#3b4c63;text-align:left;font-size:.83rem}
.choice:hover{border-color:#a7bde9;background:#f8faff}
.choice .choice-dot{display:grid;flex:none;place-items:center;width:23px;height:23px;border:1px solid #ccd5e4;border-radius:50%;color:#65758c;font-size:.67rem;font-weight:800}
.choice.selected{border-color:var(--blue);background:#eff4ff;color:#234f9e}
.choice.selected .choice-dot{border-color:var(--blue);background:var(--blue);color:#fff}
.written-form{display:flex;flex-direction:column;align-items:flex-start;gap:7px;margin-top:12px}
.input-help{color:var(--soft);font-size:.68rem}
.practice-actions{display:flex;align-items:flex-start;justify-content:space-between;gap:12px;margin-top:15px}
.hint-button{color:#9a6a11;background:#fffaf0;border-color:#f1e1bc}
.hint-text{max-width:370px;margin:9px 0;color:#7a601f;font-size:.77rem}
.check-button{min-width:130px}
.feedback{margin-top:13px;padding:13px 15px;border:1px solid #cfe9dd;border-radius:11px;background:#f0faf5;color:#28553f;font-size:.83rem}
.feedback.incorrect{border-color:#f0d6d2;background:#fff5f3;color:#873d35}
.feedback strong{display:block;margin-bottom:4px}
.next-actions{align-items:center;margin-top:11px}
.next-actions .muted{font-size:.74rem}
.test-intro{display:flex;align-items:center;justify-content:space-between;gap:18px;padding:20px;border:1px solid #f0dfb5;border-radius:15px;background:#fffaf0}
.test-intro strong{font-size:.91rem}
.test-intro p{margin:4px 0 0;color:var(--muted);font-size:.81rem}
.test-runner,.test-results{padding:21px;border:1px solid var(--line);border-radius:16px;background:#fff;box-shadow:var(--shadow)}
.test-progress-row{display:flex;align-items:center;gap:15px;margin-bottom:17px;color:var(--muted);font-size:.76rem;font-weight:750}
.test-track{height:7px;flex:1;border-radius:99px;background:#e8edf5;overflow:hidden}
.test-track span{display:block;width:0;height:100%;background:var(--blue);transition:width .2s}
.test-runner h3{margin:0 0 14px;font-size:1.1rem}
.test-feedback{margin:11px 0 0;color:var(--muted);font-size:.78rem}
.test-actions{display:flex;justify-content:space-between;gap:10px;margin-top:17px;padding-top:14px;border-top:1px solid var(--line)}
.test-actions button:disabled{opacity:.45;cursor:not-allowed}
.result-score{display:flex;align-items:center;gap:15px;margin-bottom:17px;padding:16px;border-radius:13px;background:#f2f6ff}
.result-score .score-number{display:grid;place-items:center;width:66px;height:66px;border-radius:50%;background:#fff;color:var(--blue);font-size:1.25rem;font-weight:900}
.result-score h3{margin:0;font-size:1.2rem}
.result-score p{margin:3px 0 0;color:var(--muted);font-size:.8rem}
.review-list{display:grid;gap:9px;margin:16px 0}
.review-item{padding:12px 13px;border:1px solid var(--line);border-radius:10px;background:#fff}
.review-item.correct{border-left:3px solid #51a781}
.review-item.wrong{border-left:3px solid #d47a6e}
.review-item strong{display:block;font-size:.8rem}
.review-item p{margin:4px 0 0;color:var(--muted);font-size:.75rem;line-height:1.5}
.test-results>.primary-button{margin-top:6px}
.page-footer{display:flex;justify-content:space-between;gap:14px;margin-top:48px;padding-top:17px;border-top:1px solid var(--line);color:var(--soft);font-size:.72rem}
.page-footer a{color:var(--blue);font-weight:750;text-decoration:none}
[hidden]{display:none!important}
@media(max-width:980px){.layout{grid-template-columns:190px minmax(0,1fr);gap:23px}.welcome{padding:35px 30px 26px}.welcome:after{right:20px;width:86px;height:86px}.wide-card{grid-template-columns:1fr}.graph-card{grid-template-columns:1fr}.graph-copy{display:grid;grid-template-columns:1fr auto;column-gap:12px}.graph-copy .worked-label,.graph-copy h3,.graph-copy p{grid-column:1}.graph-controls{grid-column:2;grid-row:1/4;align-content:center;flex-direction:column}.graph-controls strong{margin-left:0}}
@media(max-width:720px){.topbar{height:62px;padding:0 17px}.math-brand{font-size:.9rem}.brand-icon{width:33px;height:33px}.top-links{gap:13px;font-size:.75rem}.layout{display:block;width:calc(100% - 28px);margin:16px auto 40px}.sidebar{position:static}.progress-card{display:grid;grid-template-columns:1fr auto;gap:0 12px;padding:13px 15px}.progress-heading{grid-column:1/3}.progress-track{grid-column:1/3;margin-top:8px}.progress-card>p{margin:6px 0 9px}.score-line{grid-column:1/3;padding-top:8px}.lesson-nav{display:flex;flex-direction:row;gap:7px;margin:12px 0 18px;overflow:auto;padding:2px 1px 6px;scrollbar-width:thin}.nav-label{display:none}.lesson-nav>a{flex:none;gap:7px;padding:8px 10px;border:1px solid var(--line);background:#fff;font-size:.71rem;white-space:nowrap}.lesson-nav>a>span:first-child{width:auto}.lesson-nav .nav-practice,.lesson-nav .nav-test{margin-top:0}.formula-card{display:none}.welcome{padding:29px 21px 18px;border-radius:17px}.welcome:after{right:14px;top:17px;width:56px;height:56px;box-shadow:0 0 0 9px rgba(55,105,214,.035),0 0 0 18px rgba(55,105,214,.025)}.welcome h1{font-size:2.5rem}.welcome>p:not(.eyebrow){max-width:420px;font-size:.88rem}.welcome-stats{gap:8px;margin-top:18px;padding-top:14px;font-size:.63rem}.concept-strip{gap:10px;margin:12px 0 35px;padding:12px}.concept-icon{width:34px;height:34px}.concept-strip strong{font-size:.77rem}.concept-strip p{font-size:.67rem}.equation-chip{display:none}.lesson{margin-bottom:29px;padding-bottom:29px}.two-col{grid-template-columns:1fr;gap:10px}.mini-card{padding:16px}.wide-card{padding:16px}.slope-types{gap:6px}.slope-types>div{padding:8px 6px}.slope-types small{font-size:.61rem}.graph-card{padding:13px}.graph-copy{display:block}.graph-controls{flex-direction:row;align-items:center}.graph-controls label{font-size:.68rem}.graph-controls input{width:60px}.graph-controls strong{margin-left:auto}.practice-section,.test-section{margin:38px 0}.section-heading{align-items:flex-start}.section-heading p:not(.eyebrow){font-size:.8rem}.practice-badge,.test-badge{width:42px;height:42px;border-radius:13px;font-size:1.2rem}.practice-panel,.test-runner,.test-results{padding:14px}.practice-toolbar{align-items:flex-end}.practice-toolbar label{flex:1}.practice-toolbar select{width:100%;min-width:0}.quiet-button{font-size:.73rem}.question-card{padding:14px}.question-prompt{font-size:.94rem}.choice-list{grid-template-columns:1fr}.choice{min-height:43px}.practice-actions{align-items:center}.check-button{min-width:115px}.hint-text{max-width:220px}.test-intro{align-items:flex-start;flex-direction:column;padding:16px}.test-intro .primary-button{width:100%}.page-footer{flex-direction:column;gap:5px}}
@media(max-width:380px){.layout{width:calc(100% - 22px)}.topbar{padding:0 11px}.top-links{gap:9px;font-size:.7rem}.welcome h1{font-size:2.15rem}.welcome-stats{gap:6px;font-size:.58rem}.welcome-stats i{width:3px;height:3px}.lesson-nav>a{padding:7px 8px;font-size:.67rem}.practice-toolbar{align-items:stretch;flex-direction:column}.practice-toolbar .quiet-button{align-self:flex-start}.question-meta{align-items:flex-start;flex-direction:column;gap:3px}.question-meta span+span{text-align:left}.practice-actions{align-items:flex-start}.graph-controls{gap:6px}.graph-controls label{gap:4px;font-size:.62rem}.graph-controls input{width:52px;padding:6px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{transition:none!important}}

/* Diagnostic pretest */
.welcome-actions{display:flex;align-items:center;gap:12px;flex-wrap:wrap}
.welcome-secondary{padding:8px 4px;color:var(--blue);font-size:.84rem;font-weight:800;text-decoration:none}
.welcome-secondary:hover{text-decoration:underline}
.lesson-nav .nav-pretest{justify-content:space-between;margin-top:3px;background:#edf3ff;color:var(--blue)}
.pretest-section{margin:40px 0 48px;scroll-margin-top:24px}
.pretest-badge{display:grid;flex:none;place-items:center;width:52px;height:52px;border-radius:17px;background:#edf3ff;color:var(--blue);font-size:1.45rem;font-weight:900}
.pretest-intro{display:flex;align-items:center;justify-content:space-between;gap:18px;padding:20px;border:1px solid #dce6fb;border-radius:15px;background:#f6f8ff}
.pretest-intro strong{font-size:.91rem}
.pretest-intro p{margin:4px 0 0;color:var(--muted);font-size:.81rem}
.pretest-intro .primary-button{flex:none}
.pretest-last-result{margin-top:10px!important;color:#315cb5!important;font-weight:750}
.pretest-runner,.pretest-results{padding:21px;border:1px solid var(--line);border-radius:16px;background:#fff;box-shadow:var(--shadow)}
.pretest-progress-row{display:flex;align-items:center;gap:15px;margin-bottom:13px;color:var(--muted);font-size:.76rem;font-weight:750}
.pretest-progress-row .test-track{margin:0}
.pretest-topic{margin:0 0 6px;color:var(--blue);font-size:.68rem;font-weight:850;letter-spacing:.08em;text-transform:uppercase}
.pretest-runner h3{margin:0 0 15px;font-size:1.12rem;line-height:1.45}
.pretest-actions{align-items:center}
.pretest-nudge{margin:9px 0 0;color:#9a6a11;font-size:.77rem}
.pretest-results .diagnostic-score{margin-bottom:20px}
.diagnostic-list-heading{margin:0 0 12px;font-size:1rem}
.diagnostic-list{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.diagnostic-card{padding:12px 13px;border:1px solid var(--line);border-left:3px solid #6bb495;border-radius:10px;background:#fff}
.diagnostic-card.needs-review{border-left-color:#d39a3a;background:#fffdf7}
.diagnostic-card-top{display:flex;align-items:flex-start;justify-content:space-between;gap:10px}
.diagnostic-card-top strong{font-size:.8rem}
.diagnostic-card-top span{color:var(--muted);font-size:.67rem;font-weight:750;text-align:right}
.diagnostic-card p{margin:6px 0 9px;color:var(--muted);font-size:.73rem;line-height:1.45}
.diagnostic-actions{display:flex;align-items:center;gap:12px;flex-wrap:wrap}
.diagnostic-link{color:var(--blue);font-size:.72rem;font-weight:800;text-decoration:none}
.diagnostic-link:hover{text-decoration:underline}
.diagnostic-actions .quiet-button{min-height:31px;padding:5px 9px;font-size:.69rem}
.retake-pretest{margin-top:16px}

/* Sticky note workspace */
.layout{grid-template-columns:220px minmax(0,1fr) 258px;gap:28px;width:min(1480px,calc(100% - 48px))}
.scratchpad-panel{position:sticky;top:84px;align-self:start;min-width:0}
.scratch-note{position:relative;padding:17px 14px 12px;border:1px solid #e7d37a;border-radius:14px 14px 12px 12px;background:linear-gradient(160deg,#fff9c9 0%,#fff2a1 100%);box-shadow:0 10px 26px rgba(99,82,16,.12)}
.scratch-note:before{position:absolute;top:-9px;left:50%;width:72px;height:20px;border:1px solid rgba(180,157,75,.18);background:rgba(255,247,188,.8);content:"";transform:translateX(-50%) rotate(-2deg)}
.scratch-note-heading{position:relative;display:flex;align-items:flex-start;justify-content:space-between;gap:8px}
.scratch-eyebrow{margin:0;color:#8e7a31;font-size:.59rem;font-weight:900;letter-spacing:.1em}
.scratch-note-heading h2{margin:2px 0 0;font-size:1.17rem;letter-spacing:-.035em}
.scratch-close{display:grid;place-items:center;width:29px;height:29px;border:1px solid rgba(110,94,38,.18);border-radius:8px;background:rgba(255,255,255,.55);color:#625622;font-size:1.2rem;line-height:1}
.scratch-help{margin:8px 0 10px;color:#766c43;font-size:.68rem;line-height:1.4}
.scratch-tools{display:grid;grid-template-columns:auto minmax(44px,1fr) auto auto;align-items:center;gap:5px;margin:0 0 8px}
.scratch-color,.scratch-width{display:flex;align-items:center;gap:4px;color:#6d633e;font-size:.65rem;font-weight:800}
.scratch-color input{width:28px;height:27px;padding:2px;border:1px solid rgba(98,81,24,.24);border-radius:7px;background:#fff;cursor:pointer}
.scratch-width{flex-direction:column;align-items:flex-start;gap:0}
.scratch-width input{width:100%;height:17px;margin:0;accent-color:#7765c5}
.scratch-tool{min-height:29px;padding:4px 6px;border:1px solid rgba(98,81,24,.2);border-radius:7px;background:rgba(255,255,255,.52);color:#655a34;font-size:.64rem;font-weight:800}
.scratch-tool[aria-pressed=true]{border-color:#9688d5;background:#eeeaff;color:#4f4293}
#scratchCanvas{display:block;width:100%;height:370px;border:1px solid rgba(126,110,59,.22);border-radius:7px;background-color:#fffdf3;background-image:repeating-linear-gradient(to bottom,transparent 0 25px,rgba(102,126,170,.12) 25px 26px);cursor:crosshair;touch-action:none}
.scratch-footer{display:flex;align-items:center;justify-content:space-between;gap:7px;padding-top:8px;color:#766c43;font-size:.6rem}
.scratch-footer>div{display:flex;gap:8px}
.scratch-text-button{padding:2px;border:0;background:transparent;color:#675890;font-size:.66rem;font-weight:800}
.scratch-text-button:hover{text-decoration:underline}
.scratch-launcher{display:none;align-items:center;gap:8px;position:fixed;right:16px;bottom:16px;z-index:40;padding:11px 15px;border:1px solid #d9c767;border-radius:999px;background:#fff5b2;color:#594c18;font-size:.8rem;font-weight:850;box-shadow:0 8px 22px rgba(37,48,69,.2)}
body.scratch-collapsed .layout{grid-template-columns:235px minmax(0,1fr);width:min(1240px,calc(100% - 48px))}
body.scratch-collapsed .scratchpad-panel{display:none}
body.scratch-collapsed .scratch-launcher{display:flex}

@media(max-width:1100px){
  .layout{grid-template-columns:190px minmax(0,1fr);gap:23px;width:min(1240px,calc(100% - 48px))}
  .scratchpad-panel{display:none}
  body.scratch-open .scratchpad-panel{display:block;position:fixed;top:78px;right:14px;z-index:40;width:min(330px,calc(100vw - 28px));max-height:calc(100dvh - 92px);overflow:auto}
  body.scratch-open .scratch-launcher{display:none}
  .scratch-launcher{display:flex}
  .scratch-note{padding:17px 14px 12px}
}
@media(max-width:720px){
  .welcome-actions{align-items:flex-start;flex-direction:column;gap:6px}
  .welcome-secondary{padding:4px 0}
  .pretest-section{margin:35px 0}
  .pretest-intro{align-items:flex-start;flex-direction:column;padding:16px}
  .pretest-intro .primary-button{width:100%}
  .pretest-runner,.pretest-results{padding:14px}
  .pretest-actions{display:grid;grid-template-columns:1fr 1fr;gap:8px}
  .pretest-actions #pretestNext{grid-column:1/-1}
  .diagnostic-list{grid-template-columns:1fr}
  .diagnostic-card-top span{font-size:.64rem}
  body.scratch-open .scratchpad-panel{top:auto;right:10px;bottom:12px;left:10px;width:auto;max-height:78dvh}
  .scratch-note{padding:16px 14px 10px}
  #scratchCanvas{height:min(34dvh,310px);min-height:190px}
  .scratch-launcher{right:13px;bottom:13px}
}
@media(max-width:380px){
  .pretest-progress-row{gap:8px;font-size:.69rem}
  .diagnostic-actions{gap:8px}
  .scratch-tools{grid-template-columns:auto minmax(38px,1fr) auto auto;gap:4px}
  .scratch-tool{padding:4px 5px;font-size:.6rem}
}