/* Layout: app shell on a 12-col editorial grid (1080px). Frosted rail ≥840px, frosted bottom bar below, sticky frosted top bar. Cards are white sheets with hairlines; tint is reserved for state.
   Palette: navy ink + paper white, a single pillar-box red used only in the brand and rules; green/red for answer states. Type: Source Serif 4 for headings and questions, Roboto Flex for UI. */
:root{
  --primary:#16315F; --on-primary:#FFFFFF; --primary-container:#E3E9F4; --on-primary-container:#0B1E3D;
  --secondary:#4C5A73; --on-secondary:#FFFFFF; --secondary-container:#E6EBF3; --on-secondary-container:#152238;
  --tertiary:#B4232F; --on-tertiary:#FFFFFF; --tertiary-container:#FBE6E6; --on-tertiary-container:#5A0F16;
  --brand-red:#C8202F;
  --error:#B3261E; --on-error:#FFFFFF; --error-container:#FCE8E6; --on-error-container:#5C0F0A;
  --success:#1D6B45; --on-success:#FFFFFF; --success-container:#DDF2E6; --on-success-container:#0A2E1C;
  --surface:#F6F7F9; --sc-lowest:#FFFFFF; --sc-low:#FFFFFF; --sc:#EEF1F5; --sc-high:#E8EBF0; --sc-highest:#DFE3EA;
  --on-surface:#0F1B2D; --on-surface-variant:#4A5568; --outline:#7A8496; --outline-variant:#D6DBE3; --hair:#E2E6EC;
  --inverse-surface:#1B2638; --inverse-on-surface:#EEF1F6; --scrim:rgba(8,15,30,.45);
  --glass:rgba(246,247,249,.74); --glass-edge:rgba(15,27,45,.09);
  --shadow:0 1px 2px rgba(15,27,45,.05),0 6px 20px -10px rgba(15,27,45,.18);
  --shadow-lg:0 2px 4px rgba(15,27,45,.04),0 22px 48px -20px rgba(15,27,45,.28);
  --font-serif:"Source Serif 4","Source Serif Pro",Georgia,"Times New Roman",serif;
  --font-brand:"Roboto Flex","Roboto",system-ui,-apple-system,"Segoe UI",sans-serif;
  --font-mono:"Roboto Mono",ui-monospace,"SFMono-Regular",Menlo,Consolas,monospace;
  --ease-spring:cubic-bezier(.42,1.5,.3,.95);
  --ease-spring-soft:cubic-bezier(.32,1.1,.3,1);
  --ease-emph:cubic-bezier(.2,0,0,1);
  --r-xs:4px; --r-sm:8px; --r-md:12px; --r-lg:16px; --r-xl:20px; --r-xxl:24px; --r-full:999px;
}
:root,:root[data-theme]{color-scheme:light}

*{box-sizing:border-box}
[hidden]{display:none!important}
html,body{min-height:100%}
body{margin:0;background:var(--surface);color:var(--on-surface);font-family:var(--font-brand);font-size:16px;line-height:1.55;-webkit-font-smoothing:antialiased;-webkit-tap-highlight-color:transparent;font-optical-sizing:auto}
body.quiz-open{overflow:hidden}
h1,h2,h3,p,dl,dd{margin:0}
a{color:var(--primary);text-underline-offset:3px}
button{font:inherit;color:inherit;border:0;background:none;cursor:pointer;padding:0;text-align:inherit}
button:disabled{cursor:not-allowed}
:focus-visible{outline:3px solid var(--primary);outline-offset:2px;border-radius:4px}
.muted{color:var(--on-surface-variant)}
.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
.ms{width:1em;height:1em;font-size:24px;fill:currentColor;flex:none;display:inline-block;vertical-align:middle;overflow:visible}
.sheet{background:var(--sc-lowest);border:1px solid var(--hair);border-radius:var(--r-lg)}

/* ---------- Type ---------- */
.eyebrow{font-size:.75rem;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:var(--on-surface-variant)}
.eyebrow.red{color:var(--brand-red)}
.display{font-family:var(--font-serif);font-size:clamp(2.35rem,6.4vw,3.75rem);line-height:1.04;font-weight:600;letter-spacing:-.02em;text-wrap:balance;font-optical-sizing:auto}
.headline{font-family:var(--font-serif);font-size:clamp(1.85rem,4.6vw,2.5rem);line-height:1.1;font-weight:600;letter-spacing:-.015em;text-wrap:balance}
.title{font-family:var(--font-serif);font-size:1.375rem;line-height:1.25;font-weight:600;letter-spacing:-.005em;text-wrap:balance}
.small{font-size:.875rem}
.rule{display:block;width:44px;height:3px;border-radius:2px;background:var(--brand-red)}

/* ---------- Glass ---------- */
.glass{background:var(--glass);-webkit-backdrop-filter:blur(22px) saturate(1.5);backdrop-filter:blur(22px) saturate(1.5)}
@supports not ((backdrop-filter:blur(1px)) or (-webkit-backdrop-filter:blur(1px))){.glass{background:var(--surface)}}

/* ---------- Brand ---------- */
.logo{width:34px;height:34px;flex:none;display:block}
.logo .bg{fill:var(--primary)} .logo .tick{stroke:var(--on-primary)} .logo .band{fill:var(--brand-red)}
.brand{display:flex;align-items:center;gap:10px;color:inherit;text-decoration:none}
.rail-logo{display:block}
@media (min-width:840px){.topbar .brand .logo{display:none}}
.wm{font-family:var(--font-serif);font-weight:600;font-size:1.125rem;letter-spacing:-.01em;line-height:1;white-space:nowrap}
.wm b{font-family:var(--font-brand);font-weight:800;font-size:.6875rem;letter-spacing:.12em;text-transform:uppercase;color:var(--on-primary);background:var(--brand-red);padding:3px 6px 2px;border-radius:4px;margin-left:6px;vertical-align:3px}

/* ---------- Shell ---------- */
.rail{display:none}
.main{min-height:100vh;padding-bottom:calc(var(--dock-h,96px) + 24px)}
.topbar{position:sticky;top:0;z-index:15;padding-top:env(safe-area-inset-top,0px);transition:background-color .3s,box-shadow .3s}
.topbar:not(.scrolled){background:transparent;-webkit-backdrop-filter:none;backdrop-filter:none}
.topbar.scrolled{box-shadow:0 1px 0 var(--glass-edge)}
.topbar-in{max-width:1080px;margin:0 auto;padding-inline:16px;height:64px;display:flex;align-items:center;gap:12px}
.topbar .spacer{flex:1}
.save-chip{display:none;align-items:center;gap:6px;height:32px;padding:0 12px;border-radius:var(--r-full);font-size:.8125rem;font-weight:600;color:var(--on-surface-variant)}
.save-chip .ms{font-size:16px}
.wrap{max-width:1080px;margin:0 auto;padding-inline:16px;padding-block:4px 32px}
@media (min-width:600px){.wrap,.topbar-in{padding-inline:28px}.save-chip{display:inline-flex}}

/* Docked bar: nav icons, then the ad as its own section underneath (mobile). Beside the rail it holds only the ad. */
.dock{position:fixed;left:0;right:0;bottom:0;z-index:20;padding-bottom:env(safe-area-inset-bottom,0px);box-shadow:0 -1px 0 var(--glass-edge)}
.navbar{display:grid;grid-template-columns:repeat(4,1fr);padding:10px 4px 12px}
.dock-ad{padding:0 12px 8px}
.ad-in{display:flex;flex-direction:column;align-items:center;gap:3px;padding-top:6px;border-top:1px solid var(--hair)}
.ad-label{font-size:.625rem;line-height:14px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--on-surface-variant)}
.dock-ins{width:100%;max-width:728px;height:50px}
.dock-ad:has(ins[data-ad-status="unfilled"]){display:none}
.dock.solo .ad-in{border-top:0}
body:has(.dock.solo){padding-bottom:calc(88px + env(safe-area-inset-bottom,0px))}
body:has(.dock.solo ins[data-ad-status="unfilled"]){padding-bottom:0}
body:has(.dock.solo ins[data-ad-status="unfilled"]) .dock{display:none}
/* Question screens: the dock rises above the quiz sheet with only the ad showing, and the sheet stops just above it */
body.quiz-open.has-ad .dock{z-index:41;left:0;background:var(--surface);-webkit-backdrop-filter:none;backdrop-filter:none}
body.quiz-open .navbar{display:none}
body.quiz-open.has-ad .quiz{bottom:var(--dock-h,0px)}
body.quiz-open.has-ad .q-foot{padding-bottom:12px}
body.quiz-open.has-ad .dock-ad{padding-top:2px}
body.quiz-open.has-ad .ad-in{border-top:0}
.nav-item{display:flex;flex-direction:column;align-items:center;gap:4px;color:var(--on-surface-variant);font-size:.75rem;font-weight:650;letter-spacing:.02em;min-width:0}
.nav-ind{position:relative;width:56px;height:32px;border-radius:var(--r-full);display:grid;place-items:center;transition:background-color .25s var(--ease-emph),width .4s var(--ease-spring)}
.nav-ind::after{content:"";position:absolute;inset:0;border-radius:inherit;background:currentColor;opacity:0;transition:opacity .15s}
.nav-item:hover .nav-ind::after{opacity:.08}
.nav-item[aria-current="page"]{color:var(--on-surface)}
.nav-item[aria-current="page"] .nav-ind{background:var(--secondary-container);color:var(--on-secondary-container);width:64px}
.nbadge{position:absolute;top:-3px;right:6px;min-width:18px;height:18px;padding:0 5px;border-radius:9px;background:var(--brand-red);color:#fff;font-size:.6875rem;font-weight:700;display:grid;place-items:center;font-variant-numeric:tabular-nums}
@media (min-width:840px){
  .rail{display:flex;position:fixed;left:0;top:0;bottom:0;z-index:20;width:92px;flex-direction:column;align-items:center;gap:20px;padding-block:calc(16px + env(safe-area-inset-top,0px)) 20px;box-shadow:1px 0 0 var(--glass-edge)}
  .rail-items{display:flex;flex-direction:column;gap:14px}
  .navbar{display:none}
  .main{padding-left:92px;padding-bottom:calc(var(--dock-h,0px) + 24px)}
  .dock{left:92px}
  .dock.solo{left:0}
  body:not(.has-ad) .dock:not(.solo),.dock:has(ins[data-ad-status="unfilled"]){display:none}
  .dock-ad{padding:8px 16px 10px}
  .ad-in{border-top:0;padding-top:0}
  .dock-ins{height:90px}
  body:has(.dock.solo){padding-bottom:132px}
}
.fab{position:relative;overflow:hidden;isolation:isolate;width:56px;height:56px;border-radius:var(--r-lg);display:grid;place-items:center;background:var(--primary-container);color:var(--on-primary-container);transition:border-radius .35s var(--ease-spring),transform .35s var(--ease-spring)}
.fab:hover{border-radius:var(--r-xl)}
.fab:active{transform:scale(.95)}
.fab::before{content:"";position:absolute;inset:0;background:currentColor;opacity:0;transition:opacity .15s;z-index:-1}
.fab:hover::before{opacity:.08}
.fab-label{font-size:.6875rem;font-weight:700;color:var(--on-surface-variant);margin-top:-12px;letter-spacing:.02em}

/* ---------- Buttons ---------- */
.btn{position:relative;overflow:hidden;isolation:isolate;display:inline-flex;align-items:center;justify-content:center;gap:8px;height:48px;padding:0 24px;border-radius:var(--r-full);font-size:1rem;font-weight:650;letter-spacing:.005em;white-space:nowrap;text-decoration:none;transition:border-radius .3s var(--ease-spring),background-color .2s,color .2s,box-shadow .2s}
.btn::before,.icon-btn::before,.chip::before,.opt::before,.ex::before,.mode::before,.qcell::before,.stat-btn::before{content:"";position:absolute;inset:0;background:currentColor;opacity:0;transition:opacity .15s;pointer-events:none;z-index:-1}
.btn:hover::before,.icon-btn:hover::before,.chip:hover::before,.opt:hover::before,.ex:hover::before,.mode:hover::before,.qcell:hover::before,.stat-btn:hover::before{opacity:.06}
.btn:active::before,.icon-btn:active::before,.chip:active::before,.opt:active::before,.ex:active::before,.mode:active::before{opacity:.1}
.btn:active{border-radius:18px}
.btn.lg:active{border-radius:20px}
.btn .ms{font-size:20px}
.btn.filled{background:var(--primary);color:var(--on-primary)}
.btn.filled:hover{box-shadow:var(--shadow)}
.btn.tonal{background:var(--secondary-container);color:var(--on-secondary-container)}
.btn.tertiary,.btn.filled-t{background:var(--primary);color:var(--on-primary)}
.btn.outlined{box-shadow:inset 0 0 0 1px var(--outline-variant);color:var(--on-surface)}
.btn.text{color:var(--primary);padding:0 14px}
.btn.danger{background:var(--error);color:var(--on-error)}
.btn.danger-text{color:var(--error);padding:0 14px}
.btn.lg{height:56px;padding:0 28px;font-size:1.0625rem}
.btn.lg .ms{font-size:22px}
.btn:disabled{background:color-mix(in srgb,var(--on-surface) 10%,transparent);color:color-mix(in srgb,var(--on-surface) 38%,transparent);box-shadow:none}
.btn:disabled::before{display:none}
.btn:disabled:active{border-radius:var(--r-full)}
.btn .arrow{transition:transform .35s var(--ease-spring)}
.btn:hover .arrow{transform:translateX(3px)}
.icon-btn{position:relative;overflow:hidden;isolation:isolate;width:48px;height:48px;border-radius:var(--r-full);display:inline-grid;place-items:center;color:var(--on-surface-variant);flex:none;transition:border-radius .3s var(--ease-spring),background-color .2s}
.icon-btn:active{border-radius:18px}
.icon-btn[aria-pressed="true"]{background:var(--tertiary-container);color:var(--on-tertiary-container);border-radius:var(--r-lg)}
.icon-btn:disabled{opacity:.38}
.actions{display:flex;flex-wrap:wrap;gap:10px}

/* ---------- Chips & tags ---------- */
.chips{display:flex;flex-wrap:wrap;gap:8px}
.chip{position:relative;overflow:hidden;isolation:isolate;display:inline-flex;align-items:center;gap:6px;height:36px;padding:0 16px;border-radius:var(--r-sm);box-shadow:inset 0 0 0 1px var(--outline-variant);font-size:.875rem;font-weight:650;color:var(--on-surface-variant);background:var(--sc-lowest);transition:border-radius .3s var(--ease-spring),background-color .2s}
.chip[aria-pressed="true"]{background:var(--primary);color:var(--on-primary);box-shadow:none;border-radius:var(--r-lg)}
.chip .ms{font-size:18px}
.tag{display:inline-flex;align-items:center;gap:4px;height:24px;padding:0 9px;border-radius:var(--r-xs);font-size:.75rem;font-weight:700;letter-spacing:.02em;background:var(--sc-high);color:var(--on-surface-variant);white-space:nowrap}
.tag .ms{font-size:15px}
.tag.ok{background:var(--success-container);color:var(--on-success-container)}
.tag.warn{background:var(--tertiary-container);color:var(--on-tertiary-container)}
.tag.prog{background:var(--secondary-container);color:var(--on-secondary-container)}
.tag.pri{background:var(--primary-container);color:var(--on-primary-container)}

/* ---------- Page blocks ---------- */
.page{display:flex;flex-direction:column;gap:36px}
.stagger > *{animation:rise .6s var(--ease-spring-soft) both;animation-delay:calc(var(--i,0) * 45ms)}
@keyframes rise{from{transform:translateY(12px);opacity:.45}}
.sec{display:flex;flex-direction:column;gap:14px}
.sec-h{display:flex;align-items:flex-end;justify-content:space-between;gap:12px;flex-wrap:wrap}
.sec-h p{max-width:62ch}
.page-h{display:flex;flex-direction:column;gap:10px;padding-top:12px}
.page-h p{max-width:62ch}
.surface{background:var(--sc-lowest);border:1px solid var(--hair);border-radius:var(--r-lg)}

/* Hero */
.hero{display:grid;gap:32px;align-items:center;padding-top:20px}
.hero-main{display:flex;flex-direction:column;gap:18px;min-width:0}
.hero-sub{font-size:1.125rem;color:var(--on-surface-variant);max-width:44ch}
.trust{list-style:none;margin:2px 0 0;padding:0;display:flex;flex-direction:column;gap:8px}
.trust li{display:grid;grid-template-columns:auto minmax(0,1fr);gap:10px;align-items:start;font-size:.9375rem}
.trust .ms{font-size:20px;color:var(--success);margin-top:1px}
.hero .actions{margin-top:6px}
.next{font-size:.875rem;color:var(--on-surface-variant);display:flex;align-items:center;gap:8px;flex-wrap:wrap}
.next b{color:var(--on-surface);font-weight:700}
.next .dot{width:8px;height:8px;border-radius:50%;background:var(--success);box-shadow:0 0 0 4px color-mix(in srgb,var(--success) 18%,transparent)}
.next .dot.live{background:var(--brand-red);box-shadow:0 0 0 4px color-mix(in srgb,var(--brand-red) 18%,transparent);animation:blink 2s ease-in-out infinite}
@keyframes blink{50%{box-shadow:0 0 0 7px color-mix(in srgb,var(--brand-red) 6%,transparent)}}
@media (min-width:900px){.hero{grid-template-columns:minmax(0,1.08fr) minmax(0,.92fr);gap:48px;padding-top:28px}}

/* Preview: a real question card, the product's own UI */
.preview{position:relative;background:var(--sc-lowest);border:1px solid var(--hair);border-radius:var(--r-xl);box-shadow:var(--shadow-lg);padding:18px 18px 16px;display:flex;flex-direction:column;gap:14px;max-width:460px;width:100%;justify-self:center}
.preview::before{content:"";position:absolute;inset:10px -10px -10px 10px;border-radius:var(--r-xl);background:var(--sc);border:1px solid var(--hair);z-index:-1}
.pv-top{display:flex;align-items:center;justify-content:space-between;gap:10px;font-size:.8125rem;font-weight:650;color:var(--on-surface-variant)}
.pv-timer{display:inline-flex;align-items:center;gap:6px;height:28px;padding:0 10px;border-radius:var(--r-full);background:var(--sc);font-family:var(--font-mono);font-weight:700;font-size:.8125rem;color:var(--on-surface)}
.pv-timer .ms{font-size:15px}
.pv-bar{height:4px;border-radius:2px;background:var(--sc-high);overflow:hidden}
.pv-bar i{display:block;height:100%;width:29%;background:var(--primary);border-radius:inherit}
.pv-q{font-family:var(--font-serif);font-size:1.25rem;line-height:1.3;font-weight:600}
.pv-opts{display:flex;flex-direction:column;gap:8px}
.pv-opt{display:grid;grid-template-columns:28px minmax(0,1fr);gap:10px;align-items:center;padding:9px 12px;border-radius:var(--r-md);border:1px solid var(--hair);font-size:.9375rem}
.pv-opt span:first-child{width:28px;height:28px;border-radius:50%;display:grid;place-items:center;box-shadow:inset 0 0 0 1.5px var(--outline-variant);font-size:.8125rem;font-weight:700;color:var(--on-surface-variant)}
.pv-opt.right{background:var(--success-container);border-color:color-mix(in srgb,var(--success) 50%,transparent);color:var(--on-success-container)}
.pv-opt.right span:first-child{background:var(--success);box-shadow:none;color:var(--on-success)}
.pv-opt.right span:first-child .ms{font-size:18px}
.pv-note{display:grid;grid-template-columns:auto minmax(0,1fr);gap:8px;font-size:.8125rem;color:var(--on-surface-variant);padding-top:2px}
.pv-note .ms{font-size:18px;color:var(--success)}

/* Stats strip */
.stats{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));background:var(--sc-lowest);border:1px solid var(--hair);border-radius:var(--r-lg);overflow:hidden}
.stat,.stat-btn{display:flex;flex-direction:column;gap:6px;padding:18px 20px;min-width:0;text-align:left;color:inherit;border-top:1px solid var(--hair)}
.stats > :nth-child(-n+2){border-top:0}
.stats > :nth-child(even){border-left:1px solid var(--hair)}
.stat-btn{position:relative;overflow:hidden;isolation:isolate}
.stat .k,.stat-btn .k{font-size:.75rem;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--on-surface-variant)}
.stat .v,.stat-btn .v{font-family:var(--font-serif);font-size:clamp(1.75rem,4.6vw,2.25rem);font-weight:600;line-height:1;font-variant-numeric:tabular-nums lining-nums;letter-spacing:-.01em}
.stat .v small,.stat-btn .v small{font-family:var(--font-brand);font-size:.45em;font-weight:650;color:var(--on-surface-variant);margin-left:2px;letter-spacing:0}
.stat .s,.stat-btn .s{font-size:.8125rem;color:var(--on-surface-variant);display:inline-flex;align-items:center;gap:4px}
.stat-btn .s{color:var(--primary);font-weight:650}
.stat-btn .s .ms{font-size:16px}
.meter{height:6px;border-radius:3px;background:var(--sc-high);overflow:hidden;margin-top:2px}
.meter i{display:block;height:100%;border-radius:inherit;background:var(--success);transform-origin:left;animation:grow 1s var(--ease-emph) .2s both}
@media (min-width:760px){.stats{grid-template-columns:1.5fr 1fr 1fr 1fr}.stats > *{border-top:0!important;border-left:1px solid var(--hair)}.stats > :first-child{border-left:0}}

/* Ticket: the real test at a glance */
.ticket{display:grid;grid-template-columns:minmax(0,1fr);background:var(--sc-lowest);border:1px solid var(--hair);border-radius:var(--r-lg);overflow:hidden}
.ticket-main{padding:22px 24px 20px;display:flex;flex-direction:column;gap:16px}
.tfacts{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:12px}
.tfacts div{display:flex;flex-direction:column;gap:4px;min-width:0}
.tfacts dt{font-size:.75rem;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--on-surface-variant)}
.tfacts dd{font-family:var(--font-serif);font-size:clamp(1.5rem,4.4vw,2rem);font-weight:600;font-variant-numeric:tabular-nums lining-nums;line-height:1.05}
.tfacts dd small{font-family:var(--font-brand);font-size:.45em;font-weight:650;color:var(--on-surface-variant);margin-left:4px}
.ticket-stub{position:relative;display:flex;align-items:center;justify-content:space-between;gap:12px;padding:16px 24px;background:var(--sc);font-size:.9375rem}
.ticket-stub::before{content:"";position:absolute;left:18px;right:18px;top:0;border-top:2px dashed var(--outline-variant)}
.ticket-stub a{display:inline-flex;align-items:center;gap:6px;font-weight:700;text-decoration:none}
.ticket-stub a .ms{font-size:18px}
@media (max-width:520px){.tfacts{grid-template-columns:repeat(2,minmax(0,1fr));row-gap:16px}}
@media (max-width:599px){.ticket-stub{flex-direction:column;align-items:flex-start;gap:8px}}
@media (min-width:880px){.ticket{grid-template-columns:minmax(0,1fr) 260px}.ticket-stub{flex-direction:column;align-items:flex-start;justify-content:center;padding:22px 24px}.ticket-stub::before{left:0;right:auto;top:16px;bottom:16px;border-top:0;border-left:2px dashed var(--outline-variant)}}

/* Book: official handbook (affiliate) */
.book{display:grid;grid-template-columns:auto minmax(0,1fr);gap:24px;align-items:center;padding:22px 24px;border-radius:var(--r-lg);background:var(--sc-lowest);border:1px solid var(--hair)}
.book-art{width:86px;height:116px;perspective:600px;flex:none}
.book .cover{position:relative;width:100%;height:100%;border-radius:3px 8px 8px 3px;background:var(--primary);box-shadow:0 12px 24px -12px rgba(10,20,40,.6),inset 5px 0 0 rgba(0,0,0,.22);transform:rotateY(-16deg);transform-origin:left center;transition:transform .6s var(--ease-spring);display:flex;flex-direction:column;justify-content:flex-start;gap:6px;padding:16px 12px 0 16px;overflow:hidden}
.book:hover .cover{transform:rotateY(-4deg) translateY(-2px)}
.book .cover .emblem{display:none}
.book .cover i{display:block;height:4px;border-radius:2px;background:color-mix(in srgb,var(--on-primary) 75%,transparent)}
.book .cover i:nth-child(2){width:88%} .book .cover i:nth-child(3){width:64%} .book .cover i:nth-child(4){width:40%;opacity:.55;margin-top:6px}
.book .cover::after{content:"";position:absolute;left:5px;right:0;bottom:14px;height:3px;background:var(--brand-red)}
.book-body{display:flex;flex-direction:column;gap:8px;min-width:0}
.book-body .small{color:var(--on-surface-variant);max-width:56ch}
.book-row{display:flex;flex-wrap:wrap;align-items:center;gap:8px 14px;margin-top:4px}
.paid{font-size:.75rem;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:var(--on-surface-variant)}
@media (max-width:520px){.book{grid-template-columns:1fr;padding:22px}.book-art{width:70px;height:94px}}

/* Lists */
.list{display:flex;flex-direction:column;background:var(--sc-lowest);border:1px solid var(--hair);border-radius:var(--r-lg);overflow:hidden}
.li{display:grid;grid-template-columns:auto minmax(0,1fr) auto;gap:14px;align-items:center;padding:14px 18px;text-align:left}
.li + .li{border-top:1px solid var(--hair)}
.lead{width:36px;height:36px;border-radius:var(--r-sm);display:grid;place-items:center;background:var(--sc-high);color:var(--on-surface-variant)}
.lead .ms{font-size:20px}
.lead.ok{background:var(--success-container);color:var(--on-success-container)}
.lead.warn{background:var(--tertiary-container);color:var(--on-tertiary-container)}
.li-t{font-weight:650;line-height:1.35}
.li-s{font-size:.8125rem;color:var(--on-surface-variant);line-height:1.4}
.li-s .good{color:var(--success);font-weight:650}
.li-end{font-family:var(--font-serif);font-weight:600;font-size:1.125rem;font-variant-numeric:tabular-nums lining-nums}

/* Empty state */
.empty{display:flex;flex-direction:column;align-items:center;text-align:center;gap:10px;padding:36px 20px;color:var(--on-surface-variant)}
.empty .shape{width:56px;height:56px;border-radius:50%;display:grid;place-items:center;background:var(--sc);color:var(--on-surface-variant)}
.empty .shape svg.s{display:none}
.empty .shape .ms{font-size:26px}
.empty p{max-width:44ch}
.empty .t{color:var(--on-surface);font-weight:700}

/* Exams grid */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(170px,1fr));gap:12px}
.ex{position:relative;overflow:hidden;isolation:isolate;display:flex;flex-direction:column;gap:14px;padding:16px 16px 14px;text-align:left;transition:border-color .2s,box-shadow .25s,transform .35s var(--ease-spring)}
.ex:hover{box-shadow:var(--shadow);border-color:var(--outline-variant);transform:translateY(-1px)}
.badge{position:relative;display:flex;align-items:baseline;gap:6px}
.badge svg.s{display:none}
.badge .num{font-family:var(--font-serif);font-weight:600;font-size:2rem;line-height:1;font-variant-numeric:tabular-nums lining-nums;letter-spacing:-.02em}
.badge .ms{font-size:24px}
.ex-top{display:flex;justify-content:space-between;align-items:flex-start;gap:8px}
.ex-title{font-weight:700;font-size:.9375rem}
.ex-meta{font-size:.8125rem;color:var(--on-surface-variant);line-height:1.35}
.ex .stripe{position:absolute;left:0;top:0;bottom:0;width:3px;background:transparent}
.ex.ok .stripe{background:var(--success)} .ex.warn .stripe{background:var(--tertiary)} .ex.prog .stripe{background:var(--primary)}
.mini-bar{height:4px;border-radius:2px;background:var(--sc-high);overflow:hidden}
.mini-bar i{display:block;height:100%;border-radius:inherit;background:var(--outline);transform-origin:left;animation:grow .9s var(--ease-emph) .2s both}
.mini-bar i.ok{background:var(--success)} .mini-bar i.warn{background:var(--tertiary)}
@keyframes grow{from{transform:scaleX(0)}}

/* Chapters */
.chaps{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,320px),1fr));gap:14px}
.chap{display:grid;grid-template-columns:auto minmax(0,1fr);gap:4px 18px;padding:20px 20px 18px;scroll-margin-top:84px;transition:box-shadow .25s,border-color .2s}
.chap:hover{box-shadow:var(--shadow);border-color:var(--outline-variant)}
.chap-num{grid-row:1/3;font-family:var(--font-serif);font-size:2.75rem;line-height:.9;font-weight:600;color:var(--primary);font-variant-numeric:lining-nums;letter-spacing:-.03em;min-width:1.2ch}
.chap-num::after{content:"";display:block;width:24px;height:3px;border-radius:2px;background:var(--brand-red);margin-top:10px}
.chap-body{display:flex;flex-direction:column;gap:8px;min-width:0}
.chap-body .t{font-family:var(--font-serif);font-weight:600;font-size:1.25rem;line-height:1.25}
.chap-actions{grid-column:1/-1;display:flex;gap:6px;flex-wrap:wrap;align-items:center;padding-top:10px}
.chap-actions .btn.tonal{padding:0 20px}
.chap-actions .btn.text{padding:0 12px}
.bar{height:6px;border-radius:3px;background:var(--sc-high);overflow:hidden;display:flex}
.bar i{display:block;height:100%;transform-origin:left;animation:grow .9s var(--ease-emph) .25s both}
.bar i.ok{background:var(--success)} .bar i.warn{background:var(--tertiary)}
.topic-row{display:flex;flex-direction:column;gap:10px}
.legend{display:flex;gap:16px;flex-wrap:wrap;font-size:.8125rem;color:var(--on-surface-variant)}
.legend span{display:inline-flex;align-items:center;gap:6px}
.legend i{width:10px;height:10px;border-radius:2px;display:inline-block}
.legend i.ok{background:var(--success)} .legend i.warn{background:var(--tertiary)} .legend i.ns{background:var(--sc-high);box-shadow:inset 0 0 0 1px var(--outline-variant)}

.note{display:grid;grid-template-columns:auto minmax(0,1fr);gap:12px;padding:16px 18px;border-radius:var(--r-lg);border:1px solid var(--hair);background:var(--sc-lowest);color:var(--on-surface-variant);font-size:.9375rem}
.note .ms{color:var(--primary)}

/* ---------- Learn (static, crawlable) ---------- */
.learn{max-width:1080px;margin:0 auto;padding-inline:16px;padding-block:24px 48px;display:flex;flex-direction:column;gap:40px}
@media (min-width:600px){.learn{padding-inline:28px}}
.learn h2{font-family:var(--font-serif);font-size:clamp(1.5rem,3.8vw,2rem);line-height:1.15;font-weight:600;letter-spacing:-.015em;text-wrap:balance}
.learn p{max-width:68ch;color:var(--on-surface-variant)}
.learn-intro{display:flex;flex-direction:column;gap:12px;padding-top:32px;border-top:1px solid var(--hair)}
.guides{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,240px),1fr));gap:0;list-style:none;margin:0;padding:0;border:1px solid var(--hair);border-radius:var(--r-lg);overflow:hidden;background:var(--sc-lowest)}
.guides li{border-bottom:1px solid var(--hair);border-right:1px solid var(--hair);margin:0 -1px -1px 0}
.guides a{display:grid;grid-template-columns:auto minmax(0,1fr) auto;gap:14px;align-items:center;padding:16px 16px 16px 18px;color:inherit;text-decoration:none;height:100%;transition:background-color .2s}
.guides a:hover{background:var(--sc)}
.guides .g-n{font-family:var(--font-serif);font-size:1.75rem;font-weight:600;color:var(--primary);line-height:1;width:1.2ch;font-variant-numeric:lining-nums}
.guides .g-t{font-weight:680;line-height:1.3}
.guides .g-s{display:block;font-size:.8125rem;color:var(--on-surface-variant);font-weight:500}
.guides .ms{color:var(--on-surface-variant);transition:transform .35s var(--ease-spring)}
.guides a:hover .ms{transform:translateX(3px)}
.faq{display:flex;flex-direction:column;background:var(--sc-lowest);border:1px solid var(--hair);border-radius:var(--r-lg);overflow:hidden}
.faq details + details{border-top:1px solid var(--hair)}
.faq summary{list-style:none;cursor:pointer;display:flex;align-items:center;justify-content:space-between;gap:16px;padding:16px 20px;font-weight:650;line-height:1.35}
.faq summary::-webkit-details-marker{display:none}
.faq summary:hover{background:var(--sc)}
.faq summary .ms{flex:none;color:var(--on-surface-variant);transition:transform .4s var(--ease-spring)}
.faq details[open] summary .ms{transform:rotate(180deg)}
.faq .a{padding:0 20px 18px;color:var(--on-surface-variant);max-width:72ch}
.faq details[open] .a{animation:rise .4s var(--ease-spring-soft)}
.foot{font-size:.8125rem;color:var(--on-surface-variant);max-width:72ch}
.foot a{color:inherit}

/* ---------- Ads ---------- */

/* ---------- Quiz layer ---------- */
.quiz{position:fixed;inset:0;z-index:40;background:var(--surface);display:flex;flex-direction:column;animation:sheet-up .45s var(--ease-spring-soft)}
@keyframes sheet-up{from{transform:translateY(20px);opacity:.3}}
.q-top{display:flex;align-items:center;gap:8px;padding:calc(8px + env(safe-area-inset-top,0px)) 8px 4px}
.q-title{flex:1;min-width:0;display:flex;flex-direction:column}
.q-title .t{font-weight:700;font-size:1.0625rem;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.q-title .s{font-size:.75rem;font-weight:650;color:var(--on-surface-variant);letter-spacing:.06em;text-transform:uppercase}
.chk{display:inline-flex;align-items:center;gap:8px;white-space:nowrap;align-self:flex-start;margin-top:2px;padding:2px 2px 2px 0;font-size:.75rem;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:var(--on-surface-variant);border-radius:var(--r-full)}
.chk .sw{position:relative;width:32px;height:18px;border-radius:9px;background:var(--sc-highest);box-shadow:inset 0 0 0 1.5px var(--outline);transition:background-color .2s,box-shadow .2s;flex:none}
.chk .sw::after{content:"";position:absolute;left:4px;top:4px;width:10px;height:10px;border-radius:50%;background:var(--outline);transition:transform .35s var(--ease-spring),width .2s,height .2s,background-color .2s}
.chk[aria-checked="true"]{color:var(--primary)}
.chk[aria-checked="true"] .sw{background:var(--primary);box-shadow:none}
.chk[aria-checked="true"] .sw::after{transform:translateX(13px);background:var(--on-primary);width:12px;height:12px;top:3px}
.timer{display:inline-flex;align-items:center;gap:6px;height:36px;padding:0 14px;border-radius:var(--r-full);background:var(--sc-lowest);border:1px solid var(--hair);font-family:var(--font-mono);font-weight:700;font-size:.9375rem;font-variant-numeric:tabular-nums;transition:background-color .3s,color .3s}
.timer .ms{font-size:18px}
.timer.low{background:var(--tertiary-container);color:var(--on-tertiary-container);border-color:transparent}
.qstrip{display:flex;flex-wrap:wrap;gap:4px;width:100%;max-width:752px;margin:0 auto;padding:6px 16px 6px}
.qs{position:relative;width:26px;height:26px;border-radius:50%;display:grid;place-items:center;font-size:.6875rem;font-weight:700;font-variant-numeric:tabular-nums;color:var(--on-surface-variant);box-shadow:inset 0 0 0 1px var(--outline-variant);background:var(--sc-lowest);transition:border-radius .3s var(--ease-spring),background-color .2s,color .2s}
.qs:hover{box-shadow:inset 0 0 0 1px var(--outline)}
.qs.ans{background:var(--primary-container);color:var(--on-primary-container);box-shadow:none}
.qs.ok{background:var(--success);color:var(--on-success);box-shadow:none}
.qs.bad{background:var(--error);color:var(--on-error);box-shadow:none}
.qs.ok,.qs.bad{animation:icon-pop .45s var(--ease-spring)}
@keyframes icon-pop{40%{transform:scale(.8)}}
.qs.cur{border-radius:8px;outline:2px solid var(--primary);outline-offset:2px}
.qs.flag::after{content:"";position:absolute;top:-3px;right:-3px;width:8px;height:8px;border-radius:50%;background:var(--brand-red);box-shadow:0 0 0 2px var(--surface)}
.wprog{height:12px;margin:2px 16px 0}
.wprog svg{display:block}
.wtrack{stroke:var(--sc-highest);stroke-width:4;stroke-linecap:round;fill:none}
.wind{stroke:var(--primary);stroke-width:4;stroke-linecap:round;stroke-linejoin:round;fill:none}
.wstop{fill:var(--primary)}
.q-body{flex:1;overflow-y:auto;overscroll-behavior:contain}
.q-col{max-width:720px;margin:0 auto;padding:22px 16px 32px;display:flex;flex-direction:column;gap:20px}
.slide-f{animation:slideF .5s var(--ease-spring-soft)} .slide-b{animation:slideB .5s var(--ease-spring-soft)}
@keyframes slideF{from{transform:translateX(24px);opacity:.3}} @keyframes slideB{from{transform:translateX(-24px);opacity:.3}}
.fb{display:grid;grid-template-columns:auto minmax(0,1fr) auto;gap:10px;align-items:center;padding:8px 6px 8px 14px;border-radius:var(--r-md);font-size:.9375rem;animation:rise .45s var(--ease-spring-soft)}
.fb .ms{font-size:20px}
.fb.ok{background:var(--success-container);color:var(--on-success-container)}
.fb.bad{background:var(--error-container);color:var(--on-error-container)}
.fb .btn.text{height:36px;padding:0 12px;color:inherit;font-size:.875rem;text-decoration:underline;text-underline-offset:3px}
.q-meta{display:flex;flex-wrap:wrap;gap:8px;align-items:center}
.q-meta .count{font-family:var(--font-mono);font-weight:700;font-size:.8125rem;color:var(--on-surface-variant);margin-right:4px;font-variant-numeric:tabular-nums;letter-spacing:.02em}
.q-text{font-family:var(--font-serif);font-size:clamp(1.5rem,4.6vw,2rem);line-height:1.22;font-weight:600;letter-spacing:-.012em;text-wrap:balance}
.q-text:focus{outline:none}
.opts{display:flex;flex-direction:column;gap:10px}
.opt{position:relative;overflow:hidden;isolation:isolate;display:grid;grid-template-columns:36px minmax(0,1fr);gap:14px;align-items:center;min-height:60px;padding:11px 18px 11px 12px;border-radius:var(--r-md);background:var(--sc-lowest);box-shadow:inset 0 0 0 1px var(--hair);font-size:1.0625rem;line-height:1.35;font-weight:500;transition:border-radius .4s var(--ease-spring),background-color .2s,box-shadow .2s,transform .35s var(--ease-spring),opacity .25s}
.opts .opt{animation:rise .5s var(--ease-spring-soft) both}
.opts .opt:nth-child(2){animation-delay:35ms}.opts .opt:nth-child(3){animation-delay:70ms}.opts .opt:nth-child(4){animation-delay:105ms}
.opt:hover{box-shadow:inset 0 0 0 1px var(--outline-variant)}
.opt:active{transform:scale(.99)}
.opt-badge{width:36px;height:36px;display:grid;place-items:center;border-radius:50%;box-shadow:inset 0 0 0 1.5px var(--outline-variant);font-weight:700;font-size:.875rem;color:var(--on-surface-variant);transition:border-radius .45s var(--ease-spring),background-color .2s,box-shadow .2s}
.opt-badge .ms{font-size:20px}
.opt.sel{background:var(--primary-container);color:var(--on-primary-container);border-radius:var(--r-lg);box-shadow:inset 0 0 0 2px var(--primary)}
.opt.sel .opt-badge{background:var(--primary);box-shadow:none;color:var(--on-primary);border-radius:var(--r-sm)}
.opt.right{background:var(--success-container);color:var(--on-success-container);border-radius:var(--r-lg);box-shadow:inset 0 0 0 2px var(--success)}
.opt.right .opt-badge{background:var(--success);box-shadow:none;color:var(--on-success);border-radius:var(--r-sm)}
.opt.wrong{background:var(--error-container);color:var(--on-error-container);box-shadow:inset 0 0 0 2px var(--error);animation:shake .35s ease-in-out}
.opt.wrong .opt-badge{background:var(--error);box-shadow:none;color:var(--on-error)}
@keyframes shake{25%,75%{transform:translateX(-3px)}50%{transform:translateX(3px)}}
.opt.dim{opacity:.55}
.opt[aria-disabled="true"]{cursor:default}
.opt[aria-disabled="true"]::before{display:none}
.opt[aria-disabled="true"]:active{transform:none}
.explain{display:grid;grid-template-columns:auto minmax(0,1fr);gap:12px;padding:16px 18px;border-radius:var(--r-lg);background:var(--sc-lowest);border:1px solid var(--hair);border-left:3px solid var(--outline);animation:rise .45s var(--ease-spring-soft)}
.explain .ms{font-size:24px}
.explain.ok{border-left-color:var(--success)} .explain.bad{border-left-color:var(--error)}
.explain.ok .ms{color:var(--success)} .explain.bad .ms{color:var(--error)}
.explain strong{display:block;font-size:1rem;margin-bottom:2px}
.q-foot{padding:12px 16px calc(12px + env(safe-area-inset-bottom,0px));box-shadow:0 -1px 0 var(--glass-edge)}
.q-foot-in{max-width:720px;margin:0 auto;display:flex;align-items:center;gap:8px}
.q-foot .grow{flex:1}
.q-foot .btn.lg{min-width:136px}
.q-foot .btn.check{padding:0 18px}
.kbd-hint{font-size:.75rem;color:var(--on-surface-variant);text-align:center;padding-top:4px}
@media (hover:none){.kbd-hint{display:none}}
@media (max-width:440px){.q-foot .back{width:48px;padding:0}.q-foot .back .wide{display:none}.q-foot .btn.lg{min-width:0;padding:0 22px}.q-foot .btn.check{padding:0 14px}}

/* Navigator grid */
.qgrid{display:grid;grid-template-columns:repeat(6,minmax(0,1fr));gap:8px}
.qcell{position:relative;overflow:hidden;isolation:isolate;aspect-ratio:1;max-width:100%;border-radius:var(--r-md);display:grid;place-items:center;font-weight:700;font-variant-numeric:tabular-nums;box-shadow:inset 0 0 0 1px var(--outline-variant);transition:border-radius .3s var(--ease-spring)}
.qcell.ans{background:var(--primary-container);color:var(--on-primary-container);box-shadow:none}
.qcell.cur{box-shadow:inset 0 0 0 2px var(--primary)}
.qcell.flag::after{content:"";position:absolute;top:4px;right:4px;width:8px;height:8px;border-radius:50%;background:var(--brand-red)}

/* Results */
.res{display:flex;flex-direction:column;align-items:center;text-align:center;gap:16px;padding-top:8px}
.res-ring{position:relative;width:200px;height:200px;display:grid;place-items:center}
.res-ring .ring-center b{font-family:var(--font-serif);font-size:3rem;font-weight:600}
.ring{position:relative;display:block}
.ring-track{fill:none;stroke:var(--sc-high)}
.ring-ind{fill:none;stroke:var(--primary);stroke-linecap:round;stroke-dasharray:1 1;animation:draw 1.3s var(--ease-emph) .15s both}
.ring.pass .ring-ind{stroke:var(--success)}
.ring.fail .ring-ind{stroke:var(--tertiary)}
@keyframes draw{from{stroke-dashoffset:1}to{stroke-dashoffset:0}}
.ring-center{position:absolute;inset:0;display:grid;place-content:center;text-align:center;line-height:1.1}
.ring-center span{font-size:.8125rem;font-weight:650;color:var(--on-surface-variant)}
.res .lead-text{max-width:46ch;font-size:1.0625rem;color:var(--on-surface-variant)}
.res .chips{justify-content:center}
.res-actions{display:flex;flex-wrap:wrap;gap:10px;justify-content:center}
.burst{display:none}
.rv-list{display:flex;flex-direction:column;gap:10px}
.rv{display:flex;flex-direction:column;gap:10px;padding:16px 18px;border-radius:var(--r-lg);background:var(--sc-lowest);border:1px solid var(--hair)}
.rv-head{display:flex;align-items:center;gap:8px;font-size:.8125rem;font-weight:700;color:var(--on-surface-variant)}
.rv-head .ms{font-size:20px}
.rv.ok .rv-head .ms{color:var(--success)} .rv.bad .rv-head .ms{color:var(--error)}
.rv h3{font-family:var(--font-serif);font-size:1.125rem;font-weight:600;line-height:1.35}
.ans-line{display:grid;grid-template-columns:auto minmax(0,1fr);gap:8px;align-items:start;font-size:.9375rem}
.ans-line .ms{font-size:20px}
.ans-line.good .ms{color:var(--success)} .ans-line.bad .ms{color:var(--error)}
.rv p{font-size:.875rem;color:var(--on-surface-variant)}

/* ---------- Dialogs & sheets ---------- */
#dlg{position:fixed;inset:0;z-index:60;display:grid;place-items:center;padding:16px}
#dlg .scrim{position:absolute;inset:0;background:var(--scrim);opacity:0;transition:opacity .25s;-webkit-backdrop-filter:blur(2px);backdrop-filter:blur(2px)}
#dlg.open .scrim{opacity:1}
.dlg{position:relative;width:min(560px,100%);max-height:calc(100% - 16px);overflow:auto;background:var(--sc-lowest);color:var(--on-surface);border-radius:var(--r-xxl);padding:24px;display:flex;flex-direction:column;gap:16px;box-shadow:var(--shadow-lg);transform:scale(.94);opacity:0;transition:transform .4s var(--ease-spring),opacity .2s}
#dlg.open .dlg{transform:none;opacity:1}
.handle{display:none;width:36px;height:4px;border-radius:2px;background:var(--outline);opacity:.5;margin:0 auto}
@media (max-width:599px){
  #dlg.sheet-mode{place-items:end stretch;padding:0}
  .dlg.sheet{width:100%;max-height:92%;border-radius:var(--r-xxl) var(--r-xxl) 0 0;padding:12px 20px calc(24px + env(safe-area-inset-bottom,0px));transform:translateY(100%);opacity:1}
  .dlg.sheet .handle{display:block}
}
.dlg h2{font-family:var(--font-serif);font-size:1.5rem;font-weight:600;line-height:1.2}
.dlg-actions{display:flex;justify-content:flex-end;gap:8px;flex-wrap:wrap;padding-top:4px}
.modes{display:flex;flex-direction:column;gap:10px}
.mode{position:relative;overflow:hidden;isolation:isolate;display:grid;grid-template-columns:auto minmax(0,1fr) auto;gap:14px;align-items:center;text-align:left;padding:16px;border-radius:var(--r-md);background:var(--sc-lowest);box-shadow:inset 0 0 0 1px var(--hair);transition:border-radius .35s var(--ease-spring),background-color .2s,box-shadow .2s}
.mode[aria-checked="true"]{box-shadow:inset 0 0 0 2px var(--primary);background:var(--primary-container);color:var(--on-primary-container);border-radius:var(--r-lg)}
.mode .ico{width:44px;height:44px;border-radius:var(--r-md);display:grid;place-items:center;background:var(--sc);color:var(--on-surface)}
.mode[aria-checked="true"] .ico{background:var(--primary);color:var(--on-primary)}
.mode .mt{font-weight:700}
.mode .md{font-size:.875rem;opacity:.85;line-height:1.4}
.radio{width:22px;height:22px;border-radius:50%;box-shadow:inset 0 0 0 2px var(--outline);display:grid;place-items:center}
.mode[aria-checked="true"] .radio{box-shadow:inset 0 0 0 2px var(--primary)}
.mode[aria-checked="true"] .radio::after{content:"";width:10px;height:10px;border-radius:50%;background:var(--primary)}
.set{display:flex;flex-direction:column;gap:10px;padding-block:6px}
.set + .set{border-top:1px solid var(--hair);padding-top:16px}
.set-l{font-weight:700}
.seg{display:flex;gap:2px}
.seg button{flex:1;height:44px;display:inline-flex;align-items:center;justify-content:center;gap:6px;background:var(--sc);font-weight:650;font-size:.875rem;color:var(--on-surface-variant);border-radius:var(--r-sm);transition:border-radius .3s var(--ease-spring),background-color .2s}
.seg button:first-child{border-radius:var(--r-full) var(--r-sm) var(--r-sm) var(--r-full)}
.seg button:last-child{border-radius:var(--r-sm) var(--r-full) var(--r-full) var(--r-sm)}
.seg button[aria-pressed="true"]{background:var(--primary);color:var(--on-primary);border-radius:var(--r-full)}
.seg .ms{font-size:18px}
textarea{width:100%;min-height:84px;resize:vertical;border-radius:var(--r-sm);border:1px solid var(--outline);background:transparent;color:var(--on-surface);font-family:var(--font-mono);font-size:.75rem;line-height:1.4;padding:10px 12px}
textarea:focus{outline:2px solid var(--primary);outline-offset:-1px}
#snack{position:fixed;left:50%;bottom:calc(var(--dock-h,96px) + 16px);z-index:80;transform:translate(-50%,24px);opacity:0;background:var(--inverse-surface);color:var(--inverse-on-surface);padding:14px 18px;border-radius:var(--r-sm);font-size:.9375rem;width:max-content;max-width:min(560px,calc(100% - 32px));transition:transform .4s var(--ease-spring),opacity .2s;pointer-events:none;box-shadow:var(--shadow)}
#snack.show{transform:translate(-50%,0);opacity:1}
body.quiz-open #snack{bottom:calc(100px + env(safe-area-inset-bottom,0px))}
body.quiz-open.has-ad #snack{bottom:calc(var(--dock-h,0px) + 92px)}
@media (min-width:840px){#snack{bottom:calc(var(--dock-h,0px) + 24px)}}

@media (prefers-reduced-motion: reduce){
  *,*::before,*::after{animation-duration:.01ms!important;animation-delay:0ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}
}

/* ---------- Static pages: study guides, privacy ---------- */
.topbar.static{position:sticky}
.topbar.static .brand .logo{display:block}
.topbar.static .brand span:last-child{white-space:nowrap}
@media (max-width:440px){.topbar.static .btn.sm{width:44px;padding:0}.topbar.static .btn.sm .lbl{display:none}}
.btn.sm{height:40px;padding:0 18px;font-size:.9375rem}
.article{max-width:820px;margin:0 auto;padding:8px 16px 48px;display:flex;flex-direction:column;gap:28px}
@media (min-width:600px){.article{padding-inline:24px}}
.crumbs{font-size:.875rem;color:var(--on-surface-variant);display:flex;gap:6px;flex-wrap:wrap;align-items:center}
.crumbs a{color:inherit;text-underline-offset:3px}
.crumbs .ms{font-size:16px;opacity:.6}
.art-head{display:flex;flex-direction:column;gap:14px;padding:12px 0 28px;border-bottom:1px solid var(--hair);animation:rise .6s var(--ease-spring-soft) both}
.art-head h1{font-family:var(--font-serif);font-size:clamp(2.1rem,6vw,3.25rem);line-height:1.06;font-weight:600;letter-spacing:-.02em;text-wrap:balance;max-width:20ch}
.art-head p{max-width:58ch;color:var(--on-surface-variant);font-size:1.125rem}
.art-head .doc-meta{font-size:.875rem;color:var(--on-surface-variant);display:flex;gap:6px;flex-wrap:wrap}
.art-head .actions{margin-top:6px}
.prose{font-size:1.0625rem;line-height:1.7;display:flex;flex-direction:column;gap:14px;animation:rise .8s var(--ease-spring-soft) .08s both}
.prose > *{max-width:70ch}
.prose > table,.prose > .tablewrap,.prose > .cards2{max-width:none}
.prose h2{font-family:var(--font-serif);font-size:1.625rem;line-height:1.2;font-weight:600;margin-top:18px;letter-spacing:-.01em;text-wrap:balance}
.prose h3{font-size:1.0625rem;font-weight:720;line-height:1.3}
.prose p{margin:0}
.prose .lede{font-size:1.1875rem;line-height:1.6;color:var(--on-surface-variant)}
.prose ul{margin:0;padding-left:1.2em}
.prose ul.ticks{list-style:none;padding:0;display:flex;flex-direction:column;gap:10px}
.prose ul.ticks li{position:relative;padding-left:30px}
.prose ul.ticks li::before{content:"";position:absolute;left:4px;top:.62em;width:10px;height:10px;border-radius:2px;background:var(--brand-red)}
.prose .tip{padding:14px 18px;border-radius:0 var(--r-md) var(--r-md) 0;border-left:3px solid var(--brand-red);background:var(--sc-lowest);font-size:1rem}
.prose table{width:100%;border-collapse:separate;border-spacing:0;font-size:.9375rem;line-height:1.45;background:var(--sc-lowest);border:1px solid var(--hair);border-radius:var(--r-lg);overflow:hidden}
.prose th{text-align:left;font-size:.75rem;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:var(--on-surface-variant);padding:12px 14px;background:var(--sc)}
.prose td{padding:12px 14px;border-top:1px solid color-mix(in srgb,var(--outline-variant) 70%,transparent);vertical-align:top}
.prose table.dates td:first-child{font-family:var(--font-serif);font-weight:600;min-width:6.5em;width:30%;font-variant-numeric:tabular-nums;color:var(--primary);font-variation-settings:"wdth" 110}
.tablewrap{overflow-x:auto;border-radius:var(--r-lg)}
.tablewrap table{min-width:520px}
.tablewrap table.dates{min-width:0}
.cards2{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,240px),1fr));gap:10px}
.card{padding:16px 18px;border-radius:var(--r-lg);background:var(--sc-lowest);border:1px solid var(--hair);display:flex;flex-direction:column;gap:6px}
.cta{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:14px 20px;padding:22px 24px;border-radius:var(--r-lg);background:var(--primary-container);color:var(--on-primary-container)}
.cta h2{font-family:var(--font-serif);font-size:1.375rem;font-weight:600;line-height:1.25}
.cta p{opacity:.85;font-size:.9375rem;margin-top:2px}
.pager{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}
.pager a{display:flex;flex-direction:column;gap:2px;padding:14px 16px;border-radius:var(--r-lg);background:var(--sc-lowest);border:1px solid var(--hair);color:inherit;text-decoration:none;transition:border-radius .4s var(--ease-spring),background-color .2s;min-width:0}
.pager a:hover{border-radius:var(--r-xl);background:var(--sc)}
.pager .k{font-size:.75rem;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:var(--on-surface-variant)}
.pager .v{font-weight:680;line-height:1.3}
.pager .next{grid-column:2;text-align:right}
.site-foot{max-width:820px;margin:0 auto;padding:22px 16px 48px;font-size:.8125rem;color:var(--on-surface-variant);display:flex;flex-direction:column;gap:10px;border-top:1px solid color-mix(in srgb,var(--outline-variant) 70%,transparent)}
@media (min-width:600px){.site-foot{padding-inline:24px}}
.site-foot nav{display:flex;gap:16px;flex-wrap:wrap}
.site-foot a{color:inherit;font-weight:600}
.guide-list{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,300px),1fr));gap:12px;list-style:none;margin:0;padding:0}
.guide-list a{display:flex;flex-direction:column;gap:8px;height:100%;padding:20px;border-radius:var(--r-lg);background:var(--sc-lowest);border:1px solid var(--hair);color:inherit;text-decoration:none;transition:border-radius .45s var(--ease-spring),transform .45s var(--ease-spring),box-shadow .3s}
.guide-list a:hover{transform:translateY(-2px);box-shadow:var(--shadow);border-radius:var(--r-lg)}
.guide-list .g-n{font-family:var(--font-serif);font-size:2.25rem;line-height:1;font-weight:600;color:var(--primary)}
.guide-list h2{font-family:var(--font-serif);font-size:1.25rem;font-weight:600;line-height:1.25}
.guide-list p{font-size:.9375rem;color:var(--on-surface-variant)}

/* ---------- Topic pages ---------- */
.quick{display:flex;flex-direction:column;gap:6px;padding:18px 22px;border-radius:var(--r-lg);background:var(--sc-lowest);border:1px solid var(--hair);border-left:4px solid var(--brand-red);animation:rise .6s var(--ease-spring-soft) .04s both}
.quick p{font-size:1.125rem;line-height:1.55;max-width:66ch}
.pairs{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,330px),1fr));gap:12px;max-width:none!important}
.pair{position:relative;display:flex;flex-direction:column;gap:8px;padding:18px 18px 16px 58px;border-radius:var(--r-lg);background:var(--sc-lowest);border:1px solid var(--hair)}
.pair .pn{position:absolute;left:18px;top:14px;font-family:var(--font-serif);font-size:1.75rem;font-weight:600;color:var(--primary);line-height:1}
.pair h3{font-family:var(--font-serif);font-size:1.125rem;font-weight:600;line-height:1.3}
.pair p{font-size:.9375rem;line-height:1.55}
.pair .mem{color:var(--on-surface-variant);font-size:.875rem;padding-top:8px;border-top:1px dashed var(--outline-variant)}
.facts-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:0;max-width:none!important;background:var(--sc-lowest);border:1px solid var(--hair);border-radius:var(--r-lg);overflow:hidden}
.facts-grid div{display:flex;flex-direction:column;gap:4px;padding:16px 18px;border-left:1px solid var(--hair)}
.facts-grid div:first-child{border-left:0}
.facts-grid b{font-family:var(--font-serif);font-size:1.875rem;font-weight:600;line-height:1;color:var(--primary);font-variant-numeric:lining-nums}
.facts-grid span{font-size:.8125rem;color:var(--on-surface-variant);line-height:1.35}
.facts-grid.ten{grid-template-columns:repeat(5,minmax(0,1fr))}
.facts-grid.ten div:nth-child(n+6){border-top:1px solid var(--hair)}
.facts-grid.ten div:nth-child(6){border-left:0}
@media (max-width:620px){.facts-grid,.facts-grid.ten{grid-template-columns:repeat(2,minmax(0,1fr))}.facts-grid div{border-left:0;border-top:1px solid var(--hair)}.facts-grid div:nth-child(-n+2){border-top:0}.facts-grid div:nth-child(even){border-left:1px solid var(--hair)}}
.prose ol.steps{list-style:none;counter-reset:s;padding:0;margin:0;display:flex;flex-direction:column;gap:10px}
.prose ol.steps li{counter-increment:s;position:relative;padding-left:44px;min-height:32px}
.prose ol.steps li::before{content:counter(s);position:absolute;left:0;top:-2px;width:30px;height:30px;border-radius:50%;background:var(--primary);color:var(--on-primary);display:grid;place-items:center;font-weight:700;font-size:.875rem}
.prose .faq{max-width:none}
.related{display:flex;flex-direction:column;gap:10px}
.related ul{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,240px),1fr));gap:8px}
.related a{display:flex;align-items:center;justify-content:space-between;gap:10px;padding:14px 16px;border-radius:var(--r-md);background:var(--sc-lowest);border:1px solid var(--hair);color:inherit;text-decoration:none;font-weight:650;transition:background-color .2s}
.related a:hover{background:var(--sc)}
.related .ms{color:var(--on-surface-variant);font-size:20px}
.topic-list .g-n .ms{font-size:30px}

/* ---------- Cheat sheet ---------- */
.cheat{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,300px),1fr));gap:12px;align-items:start}
.cs{background:var(--sc-lowest);border:1px solid var(--hair);border-radius:var(--r-lg);padding:16px 18px;break-inside:avoid}
.cs h2{font-family:var(--font-serif);font-size:1.125rem;font-weight:600;margin:0 0 10px;padding-bottom:8px;border-bottom:2px solid var(--brand-red);display:inline-block}
.cs dl{margin:0;display:flex;flex-direction:column}
.cs dl div{display:grid;grid-template-columns:minmax(5.5em,auto) minmax(0,1fr);gap:10px;padding:5px 0;border-top:1px solid var(--hair);font-size:.875rem;line-height:1.35}
.cs dl div:first-child{border-top:0}
.cs dt{font-weight:750;color:var(--primary);font-variant-numeric:tabular-nums lining-nums}
.cs dd{margin:0}
.cs table{width:100%;border-collapse:collapse;font-size:.8125rem}
.cs th{text-align:left;font-size:.6875rem;letter-spacing:.06em;text-transform:uppercase;color:var(--on-surface-variant);padding:4px 6px 6px 0}
.cs td{padding:5px 6px 5px 0;border-top:1px solid var(--hair)}
.cs-test dl{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:6px 12px}
.cs-test dl div{grid-template-columns:1fr;gap:0;border-top:0;padding:0}
.cs-test dt{font-family:var(--font-serif);font-size:1.5rem;font-weight:600;line-height:1.1}
.cs-test dd{font-size:.8125rem;color:var(--on-surface-variant)}
@media (min-width:980px){.cs-tall{grid-row:span 3}}
.cs-foot{font-size:.8125rem;color:var(--on-surface-variant);text-align:center}
@media print{
  @page{size:A4;margin:10mm}
  body{background:#fff;font-size:9pt}
  .topbar,.site-foot,.no-print,.crumbs,.dock{display:none!important}
  body{padding-bottom:0!important}
  .article{max-width:none;padding:0;gap:6px}
  .art-head{padding:0 0 4px;border-bottom:2px solid var(--brand-red);animation:none}
  .art-head h1{font-size:18pt;max-width:none}
  .art-head p{font-size:9pt}
  .cheat{display:block;column-count:3;column-gap:6px}
  .cs{display:block;width:100%;padding:6px 8px;margin:0 0 6px;border-radius:6px;box-shadow:none;break-inside:avoid;page-break-inside:avoid}
  .cs h2{font-size:10pt;margin-bottom:4px;padding-bottom:2px}
  .cs dl div{padding:1.5px 0;font-size:7.5pt;gap:6px}
  .cs table{font-size:7.5pt}
  .cs-test dt{font-size:12pt}
  .cs-foot{font-size:7pt;margin:0}
  *{animation:none!important;transition:none!important}
}