:root,[data-theme=light]{--font-display:Georgia,"Iowan Old Style","Palatino Linotype",serif;--font-body:-apple-system,BlinkMacSystemFont,"Segoe UI","Inter",sans-serif;--text-xs:clamp(0.75rem,0.7rem + 0.25vw,0.875rem);--text-sm:clamp(0.875rem,0.8rem + 0.35vw,1rem);--text-base:clamp(1rem,0.95rem + 0.25vw,1.125rem);--text-lg:clamp(1.125rem,1rem + 0.75vw,1.5rem);--text-xl:clamp(1.5rem,1.2rem + 1.25vw,2.15rem);--space-2:0.5rem;--space-3:0.75rem;--space-4:1rem;--space-5:1.25rem;--space-6:1.5rem;--space-8:2rem;--space-page:clamp(0.75rem,2.4vw,1.5rem);--radius-sm:0.375rem;--radius-md:0.6rem;--radius-lg:1rem;--radius-full:999px;--color-bg:#f7f6f2;--color-surface:#fdfcf9;--color-surface-2:#f3f0ec;--color-border:rgba(40,37,29,0.12);--color-text:#28251d;--color-text-muted:#65625a;--color-text-faint:#9f9b92;--color-primary:#0d6b6f;--color-primary-2:#d9eceb;--color-success:#437a22;--color-warning:#a05a16;--color-error:#a12c7b;--shadow-sm:0 1px 2px rgba(31,27,20,0.06),0 8px 24px rgba(31,27,20,0.04);--theme-eq:#1f7a8c;--theme-ineq:#8d5a00;--theme-word:#9d3d54;--theme-func:#4754b8;--theme-geo:#6b4c2a}[data-theme=dark]{--color-bg:#171614;--color-surface:#1d1b19;--color-surface-2:#252321;--color-border:rgba(235,231,223,0.12);--color-text:#ece7df;--color-text-muted:#b3aea6;--color-text-faint:#7d786f;--color-primary:#63a8af;--color-primary-2:#253739;--color-success:#83ba5f;--color-warning:#f0b75d;--color-error:#dc78b2;--shadow-sm:0 1px 2px rgba(0,0,0,0.2),0 8px 24px rgba(0,0,0,0.2);--theme-eq:#76b9ca;--theme-ineq:#f0c86f;--theme-word:#e08ba1;--theme-func:#93a2ff;--theme-geo:#d4a574}*,:after,:before{box-sizing:border-box}html{-webkit-font-smoothing:antialiased;-webkit-text-size-adjust:100%}body{margin:0;min-height:100vh;font-family:var(--font-body);font-size:var(--text-base);line-height:1.55;background:var(--color-bg);color:var(--color-text)}button,input{font:inherit}button{cursor:pointer;border:none;background:none}a,button{color:inherit}a{text-decoration:none}.app{max-width:1160px;margin:0 auto;padding:0 var(--space-page) calc(var(--space-6) + env(safe-area-inset-bottom))}.skip-link{position:absolute;left:-9999px;top:0}.skip-link:focus{left:var(--space-4);top:var(--space-4);background:var(--color-surface);padding:var(--space-2) var(--space-3);border-radius:var(--radius-sm);z-index:100}.topbar{position:-webkit-sticky;position:sticky;top:0;z-index:30;justify-content:space-between;padding:calc(var(--space-3) + env(safe-area-inset-top)) 0 var(--space-4);background:color-mix(in srgb,var(--color-bg) 88%,transparent);-webkit-backdrop-filter:blur(14px);backdrop-filter:blur(14px)}.brand,.topbar{display:flex;gap:var(--space-3);align-items:center}.brand-mark{width:46px;height:46px;border-radius:14px;background:linear-gradient(135deg,var(--color-primary-2),transparent),var(--color-surface);display:grid;place-items:center;border:1px solid var(--color-border);box-shadow:var(--shadow-sm)}.eyebrow{font-size:var(--text-xs);text-transform:uppercase;letter-spacing:.08em;color:var(--color-text-muted)}h1,h2,h3{margin:0;line-height:1.15}h1{font-family:var(--font-display);font-size:var(--text-xl)}h2{font-size:var(--text-lg)}p{margin:0;color:var(--color-text-muted)}.hero-actions,.nav-links,.toolbar{display:flex;gap:var(--space-3);flex-wrap:wrap;align-items:center}.nav-links a{min-height:40px;padding:.45rem .85rem;border-radius:var(--radius-full);border:1px solid transparent;color:var(--color-text-muted);font-size:var(--text-sm)}.nav-links a:hover,.nav-links a[aria-current=page]{background:var(--color-surface);border-color:var(--color-border);color:var(--color-text)}.btn{min-height:46px;padding:0 var(--space-4);border-radius:var(--radius-full);border:1px solid var(--color-border);background:var(--color-surface-2);display:inline-flex;align-items:center;justify-content:center;gap:.55rem;box-shadow:var(--shadow-sm)}.btn-primary{background:var(--color-primary);color:#fff;border-color:transparent}.btn-ghost{background:transparent;box-shadow:none}.panel{background:var(--color-surface);border:1px solid var(--color-border);border-radius:var(--radius-lg);box-shadow:var(--shadow-sm)}.empty-card,.login-card,.section-card{padding:var(--space-6)}.stack{grid-gap:var(--space-4)}.stack,.topic-grid{display:grid;gap:var(--space-4)}.topic-grid{grid-template-columns:repeat(2,1fr);grid-gap:var(--space-4)}.topic-card{padding:var(--space-4);border-radius:var(--radius-md);border:1px solid var(--color-border);background:var(--color-surface-2);display:grid;grid-gap:var(--space-2);gap:var(--space-2)}.topic-head{display:flex;justify-content:space-between;gap:var(--space-2);align-items:flex-start}.topic-symbol{width:38px;height:38px;border-radius:12px;display:grid;place-items:center;font-weight:700;color:#fff}.theme-eq{background:var(--theme-eq)}.theme-ineq{background:var(--theme-ineq)}.theme-word{background:var(--theme-word)}.theme-func{background:var(--theme-func)}.theme-geo{background:var(--theme-geo)}.task-figure{margin:0;padding:var(--space-3);border-radius:var(--radius-md);border:1px solid var(--color-border);background:var(--color-surface-2)}.recognize-card img,.task-figure img,.task-figure svg{display:block;width:min(100%,320px);height:auto}.recognize-grid{display:grid;grid-template-columns:1fr 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var(--space-4);text-align:center;color:var(--color-text-faint);font-size:var(--text-sm)}.topic-card{color:inherit}.practice-card,.question-card,.review-card,.section-card{padding:var(--space-6);display:grid;grid-gap:var(--space-4);gap:var(--space-4)}.question-head{display:flex;justify-content:space-between;gap:var(--space-4);align-items:flex-start}.badge{display:inline-flex;align-items:center;gap:.4rem;border-radius:var(--radius-full);padding:.35rem .75rem;background:var(--color-primary-2);font-size:var(--text-xs);border:1px solid var(--color-border)}.timer{font-feature-settings:"tnum";font-variant-numeric:tabular-nums;font-weight:700}.progress{height:10px;background:var(--color-surface-2);border-radius:999px;overflow:hidden;border:1px solid var(--color-border)}.progress>span{display:block;height:100%;background:var(--color-primary)}.timer-modes,.timer-toggle{display:grid;grid-gap:var(--space-2);gap:var(--space-2)}.timer-hint{font-size:var(--text-sm)}.exam-mode{outline:2px solid color-mix(in srgb,var(--color-warning) 35%,transparent)}.check-list{display:grid;grid-gap:var(--space-2);gap:var(--space-2)}.check-item{align-items:flex-start;min-height:44px}.check-item,.pill-row{display:flex;gap:var(--space-2)}.pill-row{flex-wrap:wrap}.pill{padding:.45rem .8rem;border-radius:var(--radius-full);background:var(--color-surface-2);border:1px solid var(--color-border);font-size:var(--text-xs);color:var(--color-text-muted)}.prompt{color:var(--color-text);font-size:var(--text-lg)}.options{display:grid;grid-gap:var(--space-3)}.option,.options{gap:var(--space-3)}.option{display:flex;align-items:flex-start;padding:var(--space-4);border-radius:var(--radius-md);border:1px solid var(--color-border);background:var(--color-surface-2)}.option.selected{border-color:var(--color-primary);background:var(--color-primary-2)}.input-answer{width:min(280px,100%);min-height:48px;border-radius:var(--radius-md);border:1px solid var(--color-border);background:var(--color-surface-2);padding:0 var(--space-4);color:var(--color-text);font-size:16px}.feedback{padding:var(--space-4);border-radius:var(--radius-md)}.feedback.ok{background:color-mix(in srgb,var(--color-success) 16%,var(--color-surface));border:1px solid color-mix(in srgb,var(--color-success) 35%,var(--color-border))}.feedback.bad{background:color-mix(in srgb,var(--color-error) 14%,var(--color-surface));border:1px solid color-mix(in srgb,var(--color-error) 35%,var(--color-border))}.memory-illustration{display:grid;grid-template-columns:1fr 1fr;grid-gap:var(--space-3);gap:var(--space-3)}.memory-box{padding:var(--space-4);border-radius:var(--radius-md);border:1px solid var(--color-border);background:var(--color-surface-2)}.memory-box.good{outline:2px solid color-mix(in srgb,var(--color-success) 25%,transparent)}.memory-box.bad{outline:2px solid color-mix(in srgb,var(--color-error) 22%,transparent)}.algorithm{display:grid;grid-gap:var(--space-4);gap:var(--space-4);grid-template-columns:1fr 1fr}.steps{grid-gap:var(--space-3);counter-reset:step;margin-top:var(--space-4)}.step,.steps{display:grid;gap:var(--space-3)}.step{grid-template-columns:34px 1fr;grid-gap:var(--space-3);align-items:flex-start}.step:before{counter-increment:step;content:counter(step);width:34px;height:34px;border-radius:50%;display:grid;place-items:center;background:var(--color-surface-2);border:1px solid var(--color-border);font-weight:700}.tag-row{display:flex;flex-wrap:wrap;gap:var(--space-2)}.tag-btn{min-height:40px;padding:0 .85rem;border-radius:var(--radius-full);border:1px solid var(--color-border);background:var(--color-surface-2)}.tag-btn.active{background:var(--color-primary);color:#fff;border-color:transparent}.mobile-drawer,.mobile-toolbar,.nav-backdrop{display:none}.icon-btn,.menu-btn{width:44px;height:44px;min-width:44px;min-height:44px;padding:0;border-radius:var(--radius-full);border:1px solid var(--color-border);background:var(--color-surface);box-shadow:var(--shadow-sm);display:inline-flex;align-items:center;justify-content:center;color:var(--color-text)}.icon-btn:hover,.menu-btn:hover{background:var(--color-surface-2)}.icon-btn-sun{color:var(--color-warning)}.nav-backdrop{position:fixed;inset:0;background:rgba(28,24,18,.28);z-index:40}.mobile-drawer{position:fixed;top:0;right:0;z-index:50;width:min(22rem,88vw);height:100dvh;padding:calc(var(--space-3) + env(safe-area-inset-top)) var(--space-5) calc(var(--space-6) + env(safe-area-inset-bottom));background:var(--color-surface);border-left:1px solid var(--color-border);box-shadow:var(--shadow-sm);transform:translateX(110%);transition:transform .2s ease}.mobile-drawer-head{display:flex;align-items:center;justify-content:space-between;gap:var(--space-3);min-height:44px;margin-bottom:var(--space-4)}.mobile-drawer.show,.nav-backdrop.show{display:block}.mobile-drawer.show{transform:translateX(0)}.mobile-drawer a{display:flex;align-items:center;min-height:48px;padding:0 var(--space-3);border-radius:var(--radius-md);color:var(--color-text-muted)}.mobile-drawer a[aria-current=page]{background:var(--color-primary-2);color:var(--color-text)}.mobile-drawer-actions{display:flex;gap:var(--space-2);flex-wrap:wrap;margin-top:var(--space-5)}.week-list{padding-left:1.1rem}.queue-list,.week-list{margin:0;display:grid;grid-gap:var(--space-3);gap:var(--space-3)}.queue-list{list-style:none;padding:0}.queue-row{display:flex;justify-content:space-between;gap:var(--space-3);align-items:center;padding:var(--space-3);border:1px solid var(--color-border);border-radius:var(--radius-md);background:var(--color-surface-2)}.queue-actions{display:flex;gap:var(--space-2);flex-wrap:wrap}.pill.state-holds{color:var(--color-success)}.pill.state-shaky{color:var(--color-warning)}.pill.state-hole{color:var(--color-error)}.tutor-form{display:grid;grid-template-columns:1fr 1fr;grid-gap:var(--space-4);gap:var(--space-4);margin-top:var(--space-4)}.field{display:grid;grid-gap:var(--space-2);gap:var(--space-2)}.field-wide{grid-column:1/-1}.input-area,select.input-answer{width:100%;min-height:48px;border-radius:var(--radius-md);border:1px solid var(--color-border);background:var(--color-surface-2);padding:var(--space-3) var(--space-4);color:var(--color-text);font-size:16px}.input-area{resize:vertical;min-height:5.5rem}.table-wrap{overflow-x:auto;margin-top:var(--space-4)}.cohort-table{width:100%;border-collapse:collapse;font-size:var(--text-sm)}.cohort-table td,.cohort-table th{text-align:left;padding:var(--space-3);border-bottom:1px solid var(--color-border);vertical-align:top}.cohort-table th{color:var(--color-text-muted);font-size:var(--text-xs);text-transform:uppercase;letter-spacing:.06em}.digest-page{padding-top:var(--space-6)}.digest-head{display:grid;grid-gap:var(--space-3);gap:var(--space-3);margin-bottom:var(--space-5)}.digest-head h1{font-size:var(--text-xl)}.digest-grid{display:grid;grid-gap:var(--space-4);gap:var(--space-4)}@media (min-width:800px){.digest-grid{grid-template-columns:1fr 1fr}.digest-grid>:last-child:nth-child(odd){grid-column:1/-1}}body.nav-open{overflow:hidden}@media (max-width:899px){.desktop-toolbar{display:none}.mobile-toolbar{display:flex;align-items:center;gap:var(--space-3)}.mobile-drawer,.nav-backdrop{display:block;opacity:0;pointer-events:none}.mobile-drawer.show,.nav-backdrop.show{opacity:1;pointer-events:auto}.nav-backdrop:not(.show){display:none}h1{font-size:clamp(1.25rem,5vw,1.6rem)}.brand-mark{width:40px;height:40px;border-radius:12px}.empty-card,.login-card,.practice-card,.question-card,.review-card,.section-card{padding:var(--space-4)}.hero-actions,.queue-actions{flex-direction:column;align-items:stretch}.btn{width:100%;min-height:48px}.icon-btn,.menu-btn{width:44px;min-width:44px}.input-answer{width:100%}.question-head,.queue-row{flex-direction:column;align-items:stretch}.recognize-grid,.tutor-form{grid-template-columns:1fr}}@media (max-width:800px){.algorithm,.memory-illustration,.topic-grid{grid-template-columns:1fr}}@media (min-width:640px) and (max-width:899px){.topic-grid{grid-template-columns:1fr 1fr}.hero-actions{flex-direction:row}.btn{width:auto}}@media (max-width:639px){:root{--text-base:1rem;--text-lg:1.2rem;--space-6:1.15rem}.prompt{font-size:1.15rem}.option,.tag-btn{min-height:48px}}