:root{
  --bg:#FFFCF0; --card:#FFFFFF; --ink:#0F172A; --muted:#475569; --cyan:#00D5E5; --teal:#007C86;
  --amber:#F59E0B; --amber-ink:#B45309; --amber-bg:#FEF3C7; --band:#0F172A; --band-ink:#FFFFFF; --line:#CFEFF2; --head:#F4F4F6; --head-line:#E5E7EB;
  box-sizing:border-box;
  padding-top:env(safe-area-inset-top,0px);
  padding-bottom:env(safe-area-inset-bottom,0px);
}
@media (prefers-color-scheme: dark){
  :root:not([data-theme="light"]){
    --bg:#0B1320; --card:#15202F; --ink:#E8F1F5; --muted:#A7B4C4; --teal:#3FE3F0;
    --amber-ink:#FBBF24; --amber-bg:#3A2A0C; --band:#00D5E5; --band-ink:#0F172A; --line:#22364A; --head:#1F2733; --head-line:#2B3647;
  }
}
:root[data-theme="dark"]{
  --bg:#0B1320; --card:#15202F; --ink:#E8F1F5; --muted:#A7B4C4; --teal:#3FE3F0;
  --amber-ink:#FBBF24; --amber-bg:#3A2A0C; --band:#00D5E5; --band-ink:#0F172A; --line:#22364A; --head:#1F2733; --head-line:#2B3647;
}
*,*::before,*::after{box-sizing:inherit}
html{scroll-padding-top:env(safe-area-inset-top,0px)}
body::before{content:"";position:fixed;inset:0;z-index:-1;background:url("bg.webp") center / cover no-repeat;pointer-events:none;opacity:.2}
@media (prefers-color-scheme: dark){:root:not([data-theme="light"]) body::before{display:none}}
:root[data-theme="dark"] body::before{display:none}
body{margin:0;background:var(--bg);color:var(--ink);font-family:Inter,system-ui,-apple-system,"Segoe UI",sans-serif;font-size:16px;line-height:1.5}
.wrap{max-width:1100px;margin:15px auto;padding:20px 16px 48px;background:#c9deff;border-radius:16px}

.top{display:flex;align-items:center;gap:12px}
.brand{display:flex;align-items:center;gap:8px;font-weight:800;font-size:1.35rem;letter-spacing:-.02em}
.brand-dot{width:12px;height:12px;border-radius:50%;background:var(--cyan)}
.pill{display:inline-block;font-weight:400;font-size:.85rem;padding:6px 14px;border-radius:999px}

.head{display:flex;flex-direction:column;gap:18px;margin:22px 0 20px}
.hero{margin:0}
.sub{margin:10px 0 0;max-width:36rem;color:var(--muted);font-size:1rem;line-height:1.5}
.disclaimer{margin-top:32px;padding-top:16px;border-top:1px solid var(--line)}
.disclaimer p{margin:0;max-width:48rem;color:var(--muted);font-size:.8rem;line-height:1.5}
.hero h1{margin:0;font-size:clamp(2.6rem,11vw,4.5rem);font-weight:800;line-height:1;letter-spacing:-.04em}
.h1-sub{display:block;margin-top:8px;font-size:.42em;font-weight:700;letter-spacing:-.01em;color:#FFF;font-size:26px}

.filters{display:flex;gap:12px}
.filter-group{flex:1;min-width:0}
.filter-group--marks{flex:1 1 40%}
.filter-group{display:flex;flex-direction:column;gap:6px}
.filter-label{font-weight:400;font-size:.9rem}
.select-wrap{position:relative}
.select-wrap::after{content:"";position:absolute;right:18px;top:50%;width:10px;height:10px;border-right:3px solid var(--ink);border-bottom:3px solid var(--ink);transform:translateY(-70%) rotate(45deg);pointer-events:none}
.select{width:100%;min-height:44px;padding:0 42px 0 16px;border-radius:12px;border:0;background:var(--card);color:var(--ink);font:inherit;font-weight:400;font-size:1rem;appearance:none;-webkit-appearance:none;cursor:pointer}
.toggle:focus-visible,.select:focus-visible{outline:3px solid var(--cyan);outline-offset:2px}

.count{font-weight:400;font-size:.9rem;color:var(--muted);margin:0 0 12px;padding-top:14px;border-top:1px solid var(--line)}
.list{display:grid;grid-template-columns:minmax(0,1fr);gap:14px;list-style:none;margin:0;padding:0}
.list > li{display:flex;flex-direction:column}

.q{background:var(--card);border:0;border-radius:20px;padding:20px;display:flex;flex-direction:column;gap:6px;height:100%}
@media (hover:hover){.q{transition:box-shadow .2s ease}.q:hover{box-shadow:0 6px 18px rgba(15,23,42,.10)}}
@media (prefers-reduced-motion:reduce){.q{transition:none}}
.q-meta{display:flex;flex-wrap:wrap;align-items:center;gap:8px;margin:-20px -20px 0;padding:12px 20px;background:var(--head);border-bottom:1px solid var(--head-line);border-radius:19px 19px 0 0}
.q-num{font-weight:600;font-size:0.95rem;color:#00A6E7;line-height:1;margin-right:4px}
.pill-unit{border:1px solid #B5B7BA;background:#fff;font-size:11px;padding:3px 10px;color:#0F172A}
.stem{margin-top:18px;margin-bottom:22px}
.pill-marks{margin-left:auto;border:1px solid #F3D57A;background:#FFF8DB;font-size:11px;padding:3px 10px;color:#0F172A}
.stem p{margin:0 0 12px;font-weight:400;font-size:1.05rem;line-height:1.6}
.stem strong{font-weight:700}
.opts{list-style:none;margin:-8px 0 22px;padding:0;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}
.opt{display:flex;align-items:center;gap:10px;padding:10px 12px;border:1px solid var(--head-line);border-radius:12px;background:var(--card);font-size:1rem}
.opt-l{flex-shrink:0;width:26px;height:26px;border-radius:50%;background:var(--head);display:flex;align-items:center;justify-content:center;font-size:.8rem;font-weight:600}
.q.is-open .opt--correct{border-color:#22A06B;background:#E3F7EC;color:#14532D}
.q.is-open .opt--correct .opt-l{background:#22A06B;color:#fff}
.colsum{display:inline-grid;grid-template-columns:auto auto;column-gap:14px;row-gap:4px;align-self:flex-start;margin:-8px 0 22px 8px;font-size:1.5rem;font-variant-numeric:tabular-nums;letter-spacing:.08em}
.ldiv{display:inline-flex;align-items:center;align-self:flex-start;margin:-4px 0 22px 8px;font-size:1.5rem;font-variant-numeric:tabular-nums}
.ld-divisor{padding-right:10px}
.ld-dividend{border-left:2px solid var(--ink);border-bottom:2px solid var(--ink);padding:10px 22px 10px 16px;letter-spacing:.35em}
.cs-n{grid-column:2;text-align:right}
.cs-op{grid-column:1}
.cs-line{grid-column:1 / span 2;border-bottom:2px solid var(--ink);margin-top:2px;height:0}
.gparts{list-style:none;margin:-8px 0 22px;padding:0;display:flex;flex-direction:column;gap:10px;font-size:1.05rem}
.gparts .opts{margin:10px 0 0}
.gp-l{color:var(--muted)}
.opts--1{grid-template-columns:minmax(0,1fr)}
.gparts li{padding:10px 14px;border:1px solid var(--head-line);border-radius:12px;background:var(--card)}
.blank{display:inline-block;width:64px;height:1.3em;vertical-align:middle;border:1.5px solid var(--muted);border-radius:6px;margin:0 4px}
.ga{display:inline-block;margin-right:18px;white-space:nowrap}
.ga-l{color:var(--amber);font-weight:400}
.gs-l{margin:10px 0 6px;font-size:.95rem;font-weight:400;color:var(--muted)}
.gs-l:first-of-type{margin-top:0}
.match{display:grid;grid-template-columns:auto minmax(0,1fr);gap:10px 16px;margin:-8px 0 22px;align-items:start}
.m-left,.m-right{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:8px}
.m-left li{min-width:56px;text-align:center;padding:10px 12px;border:1px solid var(--head-line);border-radius:12px;background:var(--card);font-weight:600}
.m-right li{padding:10px 14px;border:1px solid var(--head-line);border-radius:12px;background:var(--card)}
.ma{display:block;font-size:1.05rem;line-height:1.5}
.done-btn{margin-left:auto;min-height:28px;padding:0 10px;border-radius:999px;border:1px solid #B5B7BA;background:var(--card);color:var(--ink);font:inherit;font-size:.72rem;cursor:pointer}
.done-btn[aria-pressed="true"]{background:#E3F7EC;border-color:#22A06B;color:#14532D}
.done-btn:focus-visible,.hide-done:focus-visible{outline:3px solid var(--cyan);outline-offset:2px}
.q.is-done{background:#F7F7F8}
.q.is-done .stem,.q.is-done .q-fig,.q.is-done .opts,.q.is-done .colsum,.q.is-done .ldiv,.q.is-done .gparts,.q.is-done .match{opacity:.55}
.hide-done{min-height:48px;padding:0 16px;border-radius:12px;border:1px solid #B5B7BA;background:var(--card);color:var(--ink);font:inherit;font-size:1rem;cursor:pointer;white-space:nowrap}
.hide-done[aria-pressed="true"]{background:var(--ink);color:var(--bg);border-color:var(--ink)}
.filter-group--done{flex:0 0 auto}
.filter-group[hidden]{display:none}
.filters .filter-group--diff{flex:1 1 40%}
.filters .filter-group--set{flex:1 1 100%}
.filters{flex-wrap:wrap}
.filters .filter-group:first-child{flex:1 1 100%}
.filter-group--done .filter-label{display:none}
.filter-group--done{align-self:flex-end}
.more-wrap{display:flex;justify-content:center;margin-top:20px}
.show-more{min-height:44px;padding:0 24px;border-radius:999px;border:1px solid #B5B7BA;background:var(--card);color:var(--ink);font:inherit;font-size:.95rem;cursor:pointer}
.show-more:focus-visible{outline:3px solid var(--cyan);outline-offset:2px}
.fexpr{display:flex;align-items:center;gap:10px;margin:-4px 0 22px 8px;font-size:1.6rem}
.fexpr .fr{font-size:.85em}
.fx-op{padding:0 2px}
.q-fig{margin:-8px 0 22px;padding:12px;background:#fff;border:1px solid var(--head-line);border-radius:14px;display:flex;justify-content:center}
.q-fig img{display:block;width:100%;max-width:260px;height:auto}
.stem p:last-child{margin-bottom:0}

.q-actions{margin-top:auto;display:flex;flex-wrap:wrap;gap:8px;align-items:center}
.toggle{align-self:flex-start;min-height:34px;padding:0 14px;border-radius:999px;border:0;background:var(--cyan);color:#FFFFFF;font:inherit;font-size:.82rem;font-weight:400;cursor:pointer}

.reveal{display:flex;flex-direction:column;gap:12px;margin-top:14px}
.reveal[hidden]{display:none}
.answer{background:var(--band);color:var(--band-ink);border-radius:16px;padding:12px 18px;display:flex;align-items:center;gap:14px;flex-wrap:wrap}
.answer-label{font-weight:400;font-size:1rem;color:var(--amber);line-height:1}
.answer-value{font-weight:400;font-size:1.3rem}
:root[data-theme="dark"] .answer-label{color:#0F172A}
@media (prefers-color-scheme: dark){:root:not([data-theme="light"]) .answer-label{color:#0F172A}}

.steps h3{margin:15px 0 15px;font-size:1rem;font-weight:400;font-weight:700;border-top:1px solid #ccc;padding-top:13px}
.steps ol{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:10px;counter-reset:step}
.steps li{display:flex;gap:12px;align-items:center;counter-increment:step}
.step-text{flex:1;min-width:0}
.steps li::before{content:counter(step);flex-shrink:0;width:30px;height:30px;border-radius:50%;background:var(--cyan);color:#0F172A;font-weight:400;font-size:.9rem;display:flex;align-items:center;justify-content:center}

.watch{background:var(--amber-bg);border-radius:16px;padding:12px 16px;display:flex;flex-direction:column;gap:2px;margin-top:12px;font-size:15px}
.watch-label{font-weight:400;font-size:1rem;color:var(--amber-ink);line-height:1.3}
.watch p{margin:0}

.fr{display:inline-flex;flex-direction:column;align-items:center;vertical-align:middle;line-height:1.1;margin:0 3px;font-weight:400;font-size:.85em}
.mixed{white-space:nowrap}
.nw{white-space:nowrap}
.mixed .fr{margin-left:2px}
.fr-n{border-bottom:2px solid currentColor;padding:0 3px 1px}
.fr-d{padding:1px 3px 0}

.empty{background:var(--card);border-radius:22px;padding:24px;text-align:center}

/* phones: step numbers smaller and level with the first line of the step */
@media (max-width:640px){
  .steps li{align-items:flex-start;gap:10px}
  .steps li::before{width:22px;height:22px;font-size:.75rem;margin-top:1px}
  .watch{border-radius:12px;font-size:14px;line-height:20px;margin-top:18px}
  .q-num{font-size:0.9rem;color:#E3B608}
  .q-meta{margin:-20px -13px 0;padding:12px 13px;border-radius:14px 14px 0 0}
  .q{border-radius:14px;padding:20px 13px}
  .toggle{padding:0 12px;font-size:.8rem}
  .done-btn{padding:0 7px;font-size:.7rem}
  .wrap{padding:20px 12px 48px}
  .steps h3{margin:12px 0 16px;font-size:1rem;font-weight:700}
  .step-text{font-size:16px;line-height:22px}
}
@media (min-width:860px){
  .wrap{padding:32px 32px 64px}
  .head{gap:20px;margin:0 0 24px}
  .filter-group{width:260px;flex:none}
  .filters{flex-wrap:nowrap}
  .filters .filter-group:first-child{flex:none}
  .filters .filter-group--diff{flex:none;width:200px}
  .filters .filter-group--set{flex:none;width:220px}
  .filter-group--done{width:auto}
  .filter-group--marks{width:170px}
  .list{grid-template-columns:repeat(2,minmax(0,1fr));align-items:stretch;gap:20px}
  .q{padding:24px 26px}
  .q-meta{margin:-24px -26px 0;padding:14px 26px}
}
@media (prefers-reduced-motion:no-preference){.toggle{transition:background-color .15s,color .15s}}

/* ---------- loaders ---------- */
.preloader{position:fixed;inset:0;z-index:50;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:16px;background:var(--bg);transition:opacity .4s ease,visibility .4s ease}
.preloader.is-hidden{opacity:0;visibility:hidden}
.pl-brand{font-size:1.8rem;font-weight:800;letter-spacing:-.03em;color:var(--ink)}
.pl-text{font-size:.9rem;color:var(--muted)}
.pl-ring{display:inline-block;width:40px;height:40px;border-radius:50%;border:4px solid rgba(0,166,231,.18);border-top-color:#00A6E7;animation:pl-spin .8s linear infinite;flex-shrink:0}
.pl-ring--sm{width:16px;height:16px;border-width:2px}
@keyframes pl-spin{to{transform:rotate(360deg)}}
.mini-loader{position:sticky;top:12px;z-index:5;display:flex;align-items:center;gap:8px;width:max-content;margin:0 auto 12px;padding:8px 16px;border-radius:999px;background:var(--card);color:var(--ink);font-size:.85rem;box-shadow:0 4px 14px rgba(15,23,42,.12)}
.mini-loader[hidden]{display:none}
.list{transition:opacity .2s ease}
.list.is-busy{opacity:.4;pointer-events:none}
.show-more{display:inline-flex;align-items:center;gap:8px}
.show-more[hidden]{display:none}
.show-more.is-busy{cursor:progress;opacity:.85}
@media (prefers-reduced-motion:reduce){.pl-ring{animation-duration:2.4s}.preloader,.list{transition:none}}

/* ---------- report link + popup ---------- */
.q-report{align-self:flex-end;margin-top:6px;padding:4px 0;background:none;border:0;color:#64748B;font:inherit;font-size:.8rem;text-decoration:underline;text-underline-offset:2px;cursor:pointer}
.q-report:hover{color:var(--ink)}
.rp-overlay{position:fixed;inset:0;z-index:60;display:flex;align-items:center;justify-content:center;padding:16px;background:rgba(15,23,42,.45)}
.rp-overlay[hidden]{display:none}
body.rp-open{overflow:hidden}
.rp-box{width:100%;max-width:420px;background:var(--card);border-radius:20px;padding:24px;box-shadow:0 12px 40px rgba(15,23,42,.25)}
.rp-title{margin:0 0 6px;font-size:1.15rem;font-weight:700}
.rp-sub{margin:0 0 14px;color:var(--muted);font-size:.95rem}
.rp-reasons{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin-bottom:14px}
.rp-reason{display:flex}
.rp-reason input{position:absolute;opacity:0;pointer-events:none}
.rp-reason span{flex:1;padding:10px 12px;border:1px solid #CBD5E1;border-radius:12px;font-size:.9rem;text-align:center;cursor:pointer}
.rp-reason input:checked+span{border-color:#00A6E7;background:#E6F6FD;color:#0F172A;font-weight:600}
.rp-reason input:focus-visible+span{outline:2px solid #00A6E7;outline-offset:2px}
.rp-note-label{display:block;margin-bottom:6px;font-size:.85rem;color:var(--muted)}
.rp-note{width:100%;box-sizing:border-box;padding:10px 12px;border:1px solid #CBD5E1;border-radius:12px;font:inherit;font-size:.95rem;resize:vertical}
.rp-actions{display:flex;justify-content:flex-end;gap:10px;margin-top:16px}
.rp-cancel{padding:10px 18px;border:0;border-radius:999px;background:#F1F5F9;color:var(--ink);font:inherit;font-size:.9rem;cursor:pointer}
.rp-send{padding:10px 22px;border:0;border-radius:999px;background:#00D5E5;color:#0F172A;font:inherit;font-size:.9rem;font-weight:600;cursor:pointer}
.rp-thanks{margin:8px 0 0;font-weight:600}