/* Классная касса — сайт. Без сборки и библиотек.
   Шрифты системные: текст — системный гротеск (как в Telegram), заголовки — Georgia/PT Serif
   (есть на Mac, Windows, iOS; на Android — Noto Serif). Акцент — синий Telegram. */
:root{
  --bg:#ffffff;
  --paper:#f6f5f1;
  --text:#15171b;
  --muted:#5d636b;
  --line:#e2e0d9;
  --rule:#d9e3ee;          /* линовка «тетради» */
  --margin:#e7a3a3;        /* красное поле тетради */
  --accent:#2481cc;
  --accent-ink:#1a6aa9;
  --accent-soft:#e7f1fa;
  --ok:#23934a;
  --danger:#cf3d2e;
  --btn-text:#ffffff;
  --max:#7b4ce0;           /* MAX — фиолетовый, только для кнопки */
  --serif:Georgia,"PT Serif","Noto Serif","Times New Roman",serif;
  --sans:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  --mono:ui-monospace,"SF Mono",Menlo,"Roboto Mono",Consolas,monospace;
  color-scheme:light;
}
@media (prefers-color-scheme:dark){
  :root:not([data-theme="light"]){
    --bg:#101215; --paper:#171a1f; --text:#ecebe7; --muted:#9ba2ab; --line:#2a2e35;
    --rule:#232a33; --margin:#6e3434; --accent:#4ea3e6; --accent-ink:#7dbcf0; --accent-soft:#16283a;
    --ok:#4cc477; --danger:#ff6b5b; --btn-text:#0b1520; --max:#a383f0; color-scheme:dark;
  }
}
:root[data-theme="dark"]{
  --bg:#101215; --paper:#171a1f; --text:#ecebe7; --muted:#9ba2ab; --line:#2a2e35;
  --rule:#232a33; --margin:#6e3434; --accent:#4ea3e6; --accent-ink:#7dbcf0; --accent-soft:#16283a;
  --ok:#4cc477; --danger:#ff6b5b; --btn-text:#0b1520; --max:#a383f0; color-scheme:dark;
}

*{box-sizing:border-box}
[hidden]{display:none!important}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--text);font:17px/1.55 var(--sans);-webkit-font-smoothing:antialiased}
img{max-width:100%;height:auto;display:block}
a{color:var(--accent-ink);text-underline-offset:.18em;text-decoration-thickness:1px}
a:hover{text-decoration-thickness:2px}
h1,h2,h3{font-family:var(--serif);font-weight:700;line-height:1.12;letter-spacing:-.01em;margin:0 0 .5em}
h1{font-size:clamp(34px,6vw,58px);letter-spacing:-.02em}
h2{font-size:clamp(26px,3.6vw,36px);margin-top:0}
h3{font-size:21px;line-height:1.25}
p{margin:0 0 1em}
ul,ol{padding-left:1.25em;margin:0 0 1em}
li{margin:.25em 0}
.num{font-variant-numeric:tabular-nums}
.muted{color:var(--muted)}
.small{font-size:14px}

.wrap{max-width:1080px;margin:0 auto;padding:0 16px}
@media (min-width:700px){.wrap{padding:0 28px}}
.prose{max-width:720px}

/* шапка */
.top{border-bottom:1px solid var(--line);background:var(--bg)}
.top .wrap{display:flex;align-items:center;gap:8px 20px;flex-wrap:wrap;padding-top:12px;padding-bottom:12px}
.brand{display:flex;align-items:center;gap:10px;color:var(--text);text-decoration:none;font-weight:700;font-size:18px;letter-spacing:-.01em;margin-right:auto}
.brand svg{flex:none}
.nav{display:flex;flex-wrap:wrap;gap:4px 16px;font-size:15px}
.nav a{color:var(--muted);text-decoration:none}
.nav a:hover,.nav a[aria-current="page"]{color:var(--text)}
@media (max-width:640px){.nav{order:3;width:100%;gap:2px 14px;font-size:14px}}

/* кнопки */
.btns{display:flex;flex-wrap:wrap;gap:10px;margin:22px 0 10px}
.btn{display:inline-flex;align-items:center;gap:9px;min-height:48px;padding:0 20px;border-radius:12px;font-weight:600;font-size:17px;
  text-decoration:none;background:var(--accent);color:var(--btn-text);border:0;cursor:pointer;font-family:var(--sans)}
.btn:hover{filter:brightness(1.06);text-decoration:none}
.btn.max{background:transparent;color:var(--text);box-shadow:inset 0 0 0 1.5px var(--line)}
.btn.max:hover{box-shadow:inset 0 0 0 1.5px var(--max)}
.btn.ghost{background:transparent;color:var(--accent-ink);box-shadow:inset 0 0 0 1.5px var(--accent)}
.btn svg{flex:none}
@media (max-width:420px){.btns .btn{flex:1 1 100%;justify-content:center}}
.fine{font-size:14px;color:var(--muted)}

/* секции */
section{padding:56px 0;border-top:1px solid var(--line)}
section.paper{background:var(--paper)}
.kicker{font-size:13px;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);font-weight:600;margin-bottom:10px}
.lead{font-size:clamp(18px,2.1vw,21px);color:var(--muted);max-width:640px}

/* герой */
.hero{padding:40px 0 48px;border-top:0}
.hero-grid{display:grid;grid-template-columns:minmax(0,1fr);gap:36px;align-items:start}
.hero-grid>*{min-width:0}
@media (min-width:960px){.hero-grid{grid-template-columns:minmax(0,1fr) 470px;gap:48px}.hero{padding:64px 0}}
.hero h1 em{font-style:normal;color:var(--accent-ink)}

/* ВЕДОМОСТЬ — тетрадный лист с красным полем, живая */
.ledger{position:relative;background:var(--bg);border:1px solid var(--line);border-radius:4px;
  background-image:linear-gradient(to bottom, transparent 31px, var(--rule) 31px, var(--rule) 32px);background-size:100% 32px;
  padding:0 14px 8px 44px;font-variant-numeric:tabular-nums}
.ledger::before{content:"";position:absolute;top:0;bottom:0;left:30px;border-left:1.5px solid var(--margin)}
.ledger-head{background:var(--bg);margin:0 -14px 0 -44px;padding:16px 14px 12px 44px;border-bottom:1.5px solid var(--text);position:relative}
.ledger-head .t{font-family:var(--serif);font-size:15px;color:var(--muted);font-style:italic}
.ledger-head .big{font-family:var(--serif);font-size:clamp(40px,8vw,56px);font-weight:700;line-height:1;letter-spacing:-.02em;margin:6px 0 4px}
.ledger-head .big small{font-size:.42em;font-weight:400;color:var(--muted);letter-spacing:0}
.ledger-head .sum{font-size:15px}
.ledger-head .sum b{color:var(--danger);font-weight:600}
.ledger-head .sum b.zero{color:var(--ok)}
.ledger-bar{height:4px;background:var(--line);margin-top:10px;border-radius:2px;overflow:hidden}
.ledger-bar i{display:block;height:100%;background:var(--ok);transition:width .35s ease}
.ledger-list{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);column-gap:16px}
.ledger-list li{margin:0}
.ledger-list button{all:unset;box-sizing:border-box;display:flex;align-items:center;gap:7px;width:100%;height:32px;cursor:pointer;font-size:15px;white-space:nowrap;overflow:hidden}
.ledger-list button:focus-visible{outline:2px solid var(--accent);outline-offset:-2px}
.ledger-list .nm{overflow:hidden;text-overflow:ellipsis;flex:1;min-width:0}
.ledger-list .mk{width:18px;flex:none;text-align:center;font-weight:700;color:var(--ok)}
.ledger-list .debt .mk{color:var(--danger)}
.ledger-list .debt .nm{color:var(--danger)}
.ledger-list .amt{font-size:13px;color:var(--danger);flex:none}
.ledger-foot{display:flex;justify-content:space-between;gap:10px;align-items:center;font-size:13px;color:var(--muted);padding-top:8px;min-height:32px}
.ledger-foot button{all:unset;cursor:pointer;color:var(--accent-ink);text-decoration:underline;text-underline-offset:.18em}
@keyframes tick{0%{transform:scale(1.6)}100%{transform:scale(1)}}
.ledger-list .just .mk{animation:tick .3s ease}
@media (max-width:380px){.ledger{padding-left:36px}.ledger::before{left:24px}.ledger-head{margin-left:-36px;padding-left:36px}.ledger-list{column-gap:8px}.ledger-list button{font-size:14px}}

/* сценарии */
.scenario{display:grid;grid-template-columns:minmax(0,1fr);gap:24px;align-items:center;padding:32px 0;border-top:1px dashed var(--line)}
.scenario:first-of-type{border-top:0;padding-top:8px}
.scenario figure{margin:0;max-width:300px;justify-self:center}
.scenario figure img{border-radius:22px;border:1px solid var(--line)}
.scenario h3{font-size:clamp(23px,2.8vw,29px)}
.scenario .figure-n{font-family:var(--serif);font-size:15px;font-style:italic;color:var(--muted);margin-top:8px;text-align:center}
@media (min-width:820px){
  .scenario{grid-template-columns:minmax(0,1fr) 300px;gap:56px}
  .scenario.flip{grid-template-columns:300px minmax(0,1fr)}
  .scenario.flip figure{order:-1}
}
.big-quote{font-family:var(--serif);font-size:clamp(26px,3.4vw,34px);line-height:1.2;margin:0 0 14px;font-weight:700}
.big-quote .num{color:var(--accent-ink)}

/* списки-пункты без иконок: тире */
.dash{list-style:none;padding:0}
.dash li{padding-left:1.1em;position:relative}
.dash li::before{content:"—";position:absolute;left:0;color:var(--muted)}

/* сравнение */
.cmp-wrap{margin-top:24px}
.cmp{width:100%;border-collapse:collapse;font-size:15px}
.cmp th,.cmp td{text-align:left;vertical-align:top;padding:12px 12px 12px 0;border-bottom:1px solid var(--line)}
.cmp thead th{font-family:var(--serif);font-size:18px;border-bottom:1.5px solid var(--text)}
.cmp tbody th{font-weight:600;width:20%}
.cmp td.us{background:var(--accent-soft);padding-left:12px}
.cmp thead th.us{background:var(--accent-soft);padding-left:12px;color:var(--accent-ink)}
@media (max-width:760px){
  .cmp thead{display:none}
  .cmp,.cmp tbody,.cmp tr,.cmp th,.cmp td{display:block;width:100%}
  .cmp tr{border-bottom:1.5px solid var(--line);padding:12px 0}
  .cmp tbody th{width:auto;border:0;padding:0 0 6px;font-family:var(--serif);font-size:18px}
  .cmp td{border:0;padding:6px 0 6px 0;display:grid;grid-template-columns:120px 1fr;gap:10px}
  .cmp td::before{content:attr(data-h);color:var(--muted);font-size:13px;line-height:1.5}
  .cmp td.us{padding:8px;border-radius:6px}
}

/* инструменты */
.tools{display:grid;gap:0;margin-top:20px;border-top:1.5px solid var(--text)}
.tool{display:grid;gap:4px 24px;padding:20px 0;border-bottom:1px solid var(--line);text-decoration:none;color:var(--text)}
.tool:hover h3{color:var(--accent-ink);text-decoration:underline;text-underline-offset:.15em}
.tool h3{margin:0}
.tool p{margin:0;color:var(--muted)}
.tool .q{font-size:13px;color:var(--muted);font-family:var(--mono)}
@media (min-width:820px){.tool{grid-template-columns:320px 1fr}}

/* цена */
.price{display:grid;gap:20px;margin-top:20px}
@media (min-width:760px){.price{grid-template-columns:1fr 1fr 1fr}}
.price-item{border-top:1.5px solid var(--text);padding-top:14px}
.price-item .v{font-family:var(--serif);font-size:44px;font-weight:700;line-height:1;letter-spacing:-.02em}
.price-item .v small{font-size:18px;font-weight:400;color:var(--muted);letter-spacing:0}

/* FAQ */
.faq details{border-bottom:1px solid var(--line);padding:4px 0}
.faq details:first-of-type{border-top:1.5px solid var(--text)}
.faq summary{cursor:pointer;list-style:none;padding:14px 32px 14px 0;font-weight:600;font-size:18px;position:relative}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";position:absolute;right:4px;top:10px;font-size:24px;font-weight:400;color:var(--muted)}
.faq details[open] summary::after{content:"−"}
.faq details>div{padding:0 0 14px;max-width:720px}

/* инструменты-формы */
.tool-box{background:var(--paper);border:1px solid var(--line);border-radius:8px;padding:18px 16px;margin:24px 0}
@media (min-width:700px){.tool-box{padding:24px}}
.fields{display:grid;gap:14px}
@media (min-width:640px){.fields.two{grid-template-columns:1fr 1fr}}
label.f{display:flex;flex-direction:column;gap:6px;font-size:15px;font-weight:600}
label.f span.h{font-weight:400;color:var(--muted);font-size:13px}
input[type=text],input[type=number],select,textarea{font:inherit;font-size:17px;color:var(--text);background:var(--bg);border:1px solid var(--line);border-radius:8px;
  padding:10px 12px;width:100%;min-width:0;min-height:46px}
input:focus,select:focus,textarea:focus{outline:2px solid var(--accent);outline-offset:-1px;border-color:transparent}
textarea{min-height:120px;resize:vertical;line-height:1.45}
.rows{display:grid;gap:10px}
.row-line{display:grid;gap:8px;grid-template-columns:minmax(0,1fr) 110px 40px;align-items:center}
@media (max-width:560px){.row-line{grid-template-columns:minmax(0,1fr) 92px 40px}}
.row-line.coll{grid-template-columns:minmax(0,1fr) 110px 80px 80px 40px;align-items:end;padding-bottom:10px;border-bottom:1px dashed var(--line)}
.mini{display:flex;flex-direction:column;gap:3px;font-size:12px;color:var(--muted);min-width:0}
.row-line .x{all:unset;cursor:pointer;width:40px;height:40px;display:flex;align-items:center;justify-content:center;color:var(--muted);font-size:22px;border-radius:8px}
.row-line .x:hover{color:var(--danger);background:var(--bg)}
.row-head{font-size:12px;color:var(--muted);display:grid;gap:8px}
@media (max-width:560px){
  .row-line.coll{grid-template-columns:minmax(0,1fr) minmax(0,1fr) minmax(0,1fr) 40px}
  .row-line.coll .mini:first-child{grid-column:1 / -1}
}
.add{all:unset;cursor:pointer;color:var(--accent-ink);font-weight:600;padding:8px 0;margin-top:4px}
.out{background:var(--bg);border:1px solid var(--line);border-left:3px solid var(--accent);border-radius:6px;padding:14px 16px;white-space:pre-wrap;
  font-size:16px;line-height:1.5;margin:16px 0 10px;min-height:80px;overflow-wrap:anywhere}
.result-big{font-family:var(--serif);font-size:clamp(44px,9vw,72px);font-weight:700;line-height:1;letter-spacing:-.02em;margin:6px 0}
.result-note{color:var(--muted);font-size:15px}
.copied{color:var(--ok);font-size:14px;margin-left:10px}
.privacy{font-size:14px;color:var(--muted);margin-top:8px}

/* статьи */
.article h2{margin-top:1.6em}
.article h3{margin-top:1.4em}
.article .lead{margin-bottom:1.2em}
.note{border-left:3px solid var(--accent);padding:4px 0 4px 16px;margin:1.4em 0;font-size:16px}
.note.warn{border-color:var(--danger)}
.toc{font-size:15px;border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:12px 0;margin:20px 0}
.toc ol{margin:0}
.src{font-size:14px;color:var(--muted)}
.src li{overflow-wrap:anywhere}
table.plain{border-collapse:collapse;width:100%;font-size:15px;margin:1em 0}
table.plain th,table.plain td{border-bottom:1px solid var(--line);padding:9px 8px 9px 0;text-align:left;vertical-align:top}
table.plain th{font-weight:600}
.tbl-scroll{overflow-x:auto;-webkit-overflow-scrolling:touch}

/* мягкий призыв внизу */
.cta-soft{border-top:1.5px solid var(--text);margin-top:40px;padding-top:20px}
.cta-soft h2{font-size:clamp(24px,3vw,30px)}

/* подвал */
footer{border-top:1px solid var(--line);padding:32px 0 40px;font-size:14px;color:var(--muted);background:var(--paper)}
footer .cols{display:grid;gap:20px}
@media (min-width:760px){footer .cols{grid-template-columns:2fr 1fr 1fr 1fr}}
footer li{padding:3px 0}
footer a{color:var(--muted)}
footer ul{list-style:none;padding:0;margin:0}
.crumbs{font-size:14px;color:var(--muted);margin:22px 0 0}
.crumbs a{color:var(--muted)}
.page-head{padding:16px 0 8px;border:0}
@media (max-width:480px){.ledger-list .amt{display:none}}