.sharpen-page,.sharpen-lesson,.sharpen-session,.sharpen-summary{min-width:0}
.sharpen-page h2,.sharpen-lesson h2,.sharpen-session h2,.sharpen-summary h2{text-wrap:balance;letter-spacing:0}
.sharpen-home{display:flex;flex-wrap:wrap;gap:14px;align-items:center;border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:18px 0;margin-bottom:24px}
.sharpen-home>span{color:var(--teal)}.sharpen-home>div{flex:1;min-width:170px}.sharpen-home h2{font-size:18px}.sharpen-home p{font-size:12px;color:var(--muted);margin-top:4px}
.sharpen-page p,.sharpen-lesson p{ text-wrap:pretty }
.sharpen-next{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:20px;padding:23px 0 25px;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.sharpen-next-copy{flex:1 1 250px;min-width:0}
.sharpen-next h2{font-size:22px;line-height:1.35;margin:7px 0}
.sharpen-next p{font-size:13px;color:var(--muted);max-width:660px}
.sharpen-meta{display:flex;flex-wrap:wrap;align-items:center;gap:7px 16px;color:var(--muted);font-size:12px;margin-top:12px}
.sharpen-meta span{display:inline-flex;align-items:center;gap:6px}
.sharpen-meta svg{width:16px;height:16px}
.sharpen-stats{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));padding:20px 0;border-bottom:1px solid var(--line)}
.sharpen-stats>div{padding:0 20px;border-right:1px solid var(--line);min-width:0}
.sharpen-stats>div:first-child{padding-left:0}
.sharpen-stats>div:last-child{border:0}
.sharpen-stats span{font-size:11px;color:var(--muted);display:block}
.sharpen-stats b{display:block;font-size:26px;font-variant-numeric:tabular-nums;line-height:1.3;margin-top:6px}
.sharpen-stats small{font-size:13px;color:var(--muted);font-weight:400}
.sharpen-tracks{display:grid;gap:28px;margin:28px 0}
.sharpen-track{min-width:0;--track-color:var(--sky);--track-soft:var(--sky-soft)}
.sharpen-track[data-topic=vectors]{--track-color:var(--teal);--track-soft:var(--teal-soft)}
.sharpen-track[data-topic=probability]{--track-color:var(--pink);--track-soft:var(--pink-soft)}
.sharpen-track[data-topic=histograms]{--track-color:var(--gold);--track-soft:var(--gold-soft)}
.sharpen-track-heading{display:flex;align-items:flex-start;gap:13px;margin-bottom:15px}
.sharpen-track-symbol{width:43px;height:43px;flex:none;display:grid;place-items:center;background:var(--track-soft);color:var(--track-color);border-radius:6px}
.sharpen-track-heading>div{min-width:0;flex:1}
.sharpen-track-heading h2{font-size:19px;line-height:1.3}
.sharpen-track-heading p{font-size:12px;color:var(--muted);margin-top:5px}
.sharpen-track-count{font-size:11px;white-space:nowrap;color:var(--track-color);font-variant-numeric:tabular-nums;padding-top:5px}
.sharpen-path{list-style:none;padding:0;margin:0;border-top:1px solid var(--line)}
.sharpen-path li{margin:0;position:relative;border-bottom:1px solid var(--line)}
.sharpen-path a{display:flex;align-items:center;gap:13px;min-height:84px;padding:15px 0;color:var(--ink)}
.sharpen-path a:hover .sharpen-lesson-copy>b{color:var(--track-color)}
.sharpen-step{position:relative;display:grid;place-items:center;border:1px solid var(--line);background:var(--surface);width:34px;height:34px;flex:none;border-radius:50%;color:var(--muted);font-size:12px;font-weight:650;font-variant-numeric:tabular-nums}
.sharpen-step.secured{border-color:var(--track-color);color:var(--track-color);background:var(--track-soft)}
.sharpen-step.review{color:var(--coral);border-color:var(--coral)}
.sharpen-step.learning{color:var(--track-color);border-color:var(--track-color)}
.sharpen-step svg{width:17px;height:17px}
.sharpen-lesson-copy{flex:1;min-width:0}
.sharpen-lesson-copy>b{font-size:13px;display:block;line-height:1.45}
.sharpen-lesson-copy>small{display:block;font-size:11px;color:var(--muted);margin-top:4px;line-height:1.55}
.sharpen-path-tail{display:flex;flex-direction:column;align-items:flex-end;gap:4px;flex:none;color:var(--muted);font-size:10px;font-variant-numeric:tabular-nums}
.sharpen-path-tail svg{width:17px;height:17px;color:var(--track-color)}
.sharpen-review-note{display:flex;align-items:flex-start;gap:9px;color:var(--muted);font-size:12px;margin-top:24px}
.sharpen-review-note svg{flex:none;color:var(--coral);width:17px;height:17px;margin-top:3px}
.sharpen-plan{margin:30px 0 0;border-top:1px solid var(--line);padding-top:20px}
.sharpen-plan summary{display:flex;align-items:center;justify-content:space-between;font-weight:650;min-height:44px;font-size:14px;list-style:none}
.sharpen-plan summary svg{width:18px}
.sharpen-plan ol{list-style:none;padding:8px 0 0;margin:0;display:grid;gap:0}
.sharpen-plan li{display:flex;gap:12px;align-items:center;padding:12px 0;border-bottom:1px solid var(--line);font-size:12px}
.sharpen-plan-day{width:32px;flex:none;color:var(--muted);font-variant-numeric:tabular-nums}
.sharpen-plan li>span:nth-child(2){flex:1;min-width:0}
.sharpen-plan li small{display:block;font-size:10px;color:var(--muted);margin-top:2px}
.sharpen-plan li[aria-current=step]{color:var(--teal);font-weight:650}
.sharpen-resume{display:flex;flex-wrap:wrap;justify-content:space-between;align-items:center;gap:12px;padding:15px 0;border-bottom:1px solid var(--line);font-size:12px;color:var(--teal)}
.sharpen-resume>span{display:flex;align-items:center;gap:8px}
.sharpen-lesson-layout{display:grid;grid-template-columns:minmax(0,1fr);gap:24px}
.sharpen-rule{border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:22px 0}
.sharpen-rule h2{font-size:19px;margin:8px 0 12px}
.sharpen-rule-copy{font-size:14px;line-height:1.8}
.sharpen-rule-copy>.math-display{font-size:22px;line-height:1.5;max-width:100%;overflow-x:auto;overflow-y:hidden;text-align:left;padding:9px 0 12px;scrollbar-width:thin}
.sharpen-rule-copy>.math-display>.katex-display{margin:0;text-align:left}
.sharpen-rule-copy>.math-display>.katex-display>.katex{display:table;margin:0}
.sharpen-rule ol{padding-left:22px;margin:14px 0 0;font-size:13px}
.sharpen-rule li{margin:9px 0;padding-left:5px}
.sharpen-example,.sharpen-trap{padding:23px 0;border-bottom:1px solid var(--line);min-width:0}
.sharpen-example h2,.sharpen-trap h2{font-size:17px;margin-bottom:12px}
.sharpen-example>p{font-size:14px}
.sharpen-example .solution-steps{margin-bottom:0}
.sharpen-trap{display:grid;gap:10px}
.sharpen-trap h2{display:flex;align-items:center;gap:8px;margin:0}
.sharpen-trap h2 svg{color:var(--coral);width:19px}
.sharpen-trap p{font-size:13px}
.sharpen-trap .sharpen-wrong{color:var(--coral)}
.sharpen-cue{padding:15px 0 0;font-size:12px;color:var(--muted)}
.sharpen-cue b{color:var(--ink)}
.sharpen-source{font-size:11px;margin:-12px 0 22px;color:var(--muted)}
.sharpen-source a{display:inline-flex;align-items:center;gap:6px;min-height:44px}
.sharpen-source svg{width:15px;height:15px}
.sharpen-lesson-actions{display:flex;flex-wrap:wrap;gap:10px;align-items:center;margin-top:22px}
.sharpen-links{margin-top:22px;display:flex;flex-wrap:wrap;gap:10px 25px;font-size:12px}
.sharpen-links a{display:flex;gap:7px;align-items:center;color:var(--teal);min-height:44px}
.sharpen-links svg{width:17px;height:17px}
.sharpen-visual{max-width:560px;min-width:0;margin:16px 0 0}
.sharpen-visual svg{display:block;width:100%;height:auto;max-height:330px}
.sharpen-diagram text{fill:var(--muted);font:13px Studio,Arial,sans-serif}
.sharpen-axis{fill:none;stroke:var(--muted);stroke-width:1.4}
.sharpen-line{fill:none;stroke:var(--teal);stroke-width:3}
.sharpen-area-a{fill:var(--teal-soft)}.sharpen-area-b{fill:var(--coral-soft)}
.sharpen-dot{fill:var(--teal)}
.sharpen-median{fill:none;stroke:var(--coral);stroke-width:2;stroke-dasharray:5 4}
.sharpen-session .question-layout{max-width:1060px}
.sharpen-session .question-surface{min-width:0}
.sharpen-session .question-title{font-size:20px;line-height:1.6}
.sharpen-stage{display:flex;gap:8px;flex-wrap:wrap;font-size:11px;color:var(--muted);align-items:center;margin-bottom:16px}
.sharpen-stage b{color:var(--teal)}
.sharpen-session .feedback{scroll-margin-top:90px}
.sharpen-confidence{display:flex;gap:6px;margin-top:14px}
.sharpen-confidence button{flex:1;min-height:44px;background:var(--surface);border:1px solid var(--line);border-radius:5px;font-size:12px;color:var(--muted)}
.sharpen-confidence button.active{background:var(--teal-soft);border-color:var(--teal);color:var(--teal)}
.sharpen-feedback{display:flex;gap:9px;align-items:flex-start}
.sharpen-feedback>svg{width:21px;height:21px;flex:none;margin-top:2px}
.sharpen-feedback>div{min-width:0}
.sharpen-feedback b{display:block}
.sharpen-earned{display:inline-flex;gap:5px;align-items:center;font-size:12px;color:var(--teal);font-variant-numeric:tabular-nums;margin-top:10px}
.sharpen-earned svg{width:16px;height:16px}
.sharpen-summary-result{border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:25px 0;display:flex;align-items:center;gap:20px}
.sharpen-summary-medal{width:62px;height:62px;flex:none;background:var(--gold-soft);color:var(--gold);border-radius:8px;display:grid;place-items:center}
.sharpen-summary-medal svg{width:30px;height:30px}
.sharpen-summary-result>div:last-child{min-width:0}
.sharpen-summary-result h2{font-size:21px}
.sharpen-summary-result p{font-size:13px;color:var(--muted);margin-top:5px}
.sharpen-summary-score{font-variant-numeric:tabular-nums;font-size:14px;color:var(--teal);margin-top:9px}
.sharpen-summary .question-actions{margin-top:20px}
.sharpen-page button,.sharpen-lesson button,.sharpen-session button,.sharpen-summary button{min-height:44px}
@media(min-width:1100px){.sharpen-tracks{grid-template-columns:repeat(3,minmax(0,1fr));gap:22px}.sharpen-track-heading{min-height:106px}.sharpen-track-count{display:none}.sharpen-path a{min-height:116px}.sharpen-lesson-layout{grid-template-columns:minmax(0,1fr) minmax(250px,.7fr);gap:32px}.sharpen-lesson-main .sharpen-rule{border-bottom:0}.sharpen-lesson-side{border-left:1px solid var(--line);padding-left:28px}.sharpen-lesson-side .sharpen-trap{padding-top:22px}}
@media(max-width:550px){.sharpen-next{padding:18px 0}.sharpen-next h2{font-size:20px}.sharpen-next>.primary{width:100%}.sharpen-stats>div{padding:0 10px}.sharpen-stats b{font-size:23px}.sharpen-stats span{font-size:10px}.sharpen-track-heading{gap:10px}.sharpen-track-count{font-size:10px}.sharpen-path a{gap:10px}.sharpen-step{width:30px;height:30px}.sharpen-rule-copy>.math-display{font-size:20px}.sharpen-lesson-actions>*{flex:1 1 150px}.sharpen-session .page-heading{align-items:flex-start}.sharpen-session .page-heading .secondary{padding:10px;min-width:44px}.sharpen-session .page-heading .secondary .button-label{display:none}.sharpen-session .question-title{font-size:18px}.sharpen-summary-result{gap:13px}.sharpen-summary-medal{width:48px;height:48px}.sharpen-summary-result h2{font-size:18px}}
@media(prefers-reduced-motion:no-preference){.sharpen-confidence button{transition:background-color .12s ease-out,border-color .12s ease-out}.sharpen-lesson-actions button:active,.sharpen-session .question-actions button:active{transform:scale(.96)}}
@media(min-width:1100px){.sharpen-tracks:has(>.sharpen-track:nth-child(4)){grid-template-columns:repeat(2,minmax(0,1fr))}.sharpen-tracks:has(>.sharpen-track:nth-child(4)) .sharpen-track-heading{min-height:74px}.sharpen-tracks:has(>.sharpen-track:nth-child(4)) .sharpen-path a{min-height:90px}}