/* SERU course design system. Tokens first; light + dark. System font stack (no font origin, CSP-safe).
   Palette: deep teal brand + one amber call-to-action. Radius scale: 12px surfaces, 999px buttons/pills. */
:root{
  --bg:#f2f6f5;--panel:#fff;--ink:#10201e;--muted:#475a57;--line:#d5e0de;
  --accent:#0a6b5c;--accent-ink:#fff;--soft:#e2f0ec;
  --brand:#08332e;--brand-2:#0d4a42;--on-brand:#f1faf7;--on-brand-muted:#b5d4cd;
  --cta:#f5b301;--cta-ink:#1b1400;--cta-hover:#ffc933;
  --ok:#1b7a3d;--bad:#b3261e;--warn:#fdf3dc;--warn-line:#e8cf8a;
  --shadow:0 10px 30px -12px rgba(8,51,46,.28);
  --r:12px;
}
@media(prefers-color-scheme:dark){:root:not([data-theme="light"]){
  --bg:#0c1413;--panel:#142120;--ink:#e7f1ef;--muted:#9fb5b1;--line:#25403b;
  --accent:#4fd1b5;--accent-ink:#05211c;--soft:#123029;
  --brand:#0a2a26;--brand-2:#0f3d36;--on-brand:#eefaf6;--on-brand-muted:#a9cbc3;
  --shadow:0 10px 30px -12px rgba(0,0,0,.6);--warn:#2b2616;--warn-line:#6b5a22;--ok:#5ad083;--bad:#ff8a80;
}}
:root[data-theme="dark"]{
  --bg:#0c1413;--panel:#142120;--ink:#e7f1ef;--muted:#9fb5b1;--line:#25403b;
  --accent:#4fd1b5;--accent-ink:#05211c;--soft:#123029;
  --brand:#0a2a26;--brand-2:#0f3d36;--on-brand:#eefaf6;--on-brand-muted:#a9cbc3;
  --shadow:0 10px 30px -12px rgba(0,0,0,.6);--warn:#2b2616;--warn-line:#6b5a22;--ok:#5ad083;--bad:#ff8a80;
}
:root[data-theme="light"]{color-scheme:light}
:root[data-theme="dark"]{color-scheme:dark}
@media(prefers-color-scheme:dark){:root:not([data-theme="light"]){color-scheme:dark}}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:72px}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
body{margin:0;background:var(--bg);color:var(--ink);font:17px/1.6 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif}
a{color:var(--accent)}
img,svg{max-width:100%}
.wrap{max-width:1080px;margin:0 auto;padding:0 18px}
.wrap.narrow{max-width:760px}
.ic{width:1.25em;height:1.25em;flex:none;fill:none;stroke:currentColor;stroke-width:2;stroke-linecap:round;stroke-linejoin:round;vertical-align:-.25em}

/* header */
header.site{background:var(--panel);border-bottom:1px solid var(--line);position:sticky;top:0;z-index:20}
header.site .wrap{display:flex;align-items:center;justify-content:space-between;gap:12px;height:64px}
header.site a.brand{display:flex;align-items:center;gap:10px;font-weight:750;color:var(--ink);text-decoration:none;letter-spacing:-.01em}
.mark{display:grid;place-items:center;width:32px;height:32px;border-radius:9px;background:var(--brand);color:var(--cta)}
header.site nav{display:flex;align-items:center;gap:4px;white-space:nowrap}
header.site nav a{padding:.55rem .75rem;border-radius:999px;font-size:.95rem;font-weight:600;color:var(--ink);text-decoration:none;min-height:44px;display:inline-flex;align-items:center}
header.site nav a:hover{background:var(--soft)}
header.site nav a.signin{border:1.5px solid var(--accent);color:var(--accent)}
@media(max-width:560px){header.site nav a.opt{display:none}header.site a.brand span.long{display:none}}

/* typography */
main{padding:28px 0 64px}
h1{font-size:clamp(1.75rem,5.4vw,2.6rem);line-height:1.12;letter-spacing:-.02em;margin:0 0 .7rem}
h2{font-size:clamp(1.4rem,3.8vw,1.85rem);line-height:1.2;letter-spacing:-.015em;margin:2.6rem 0 .6rem}
h3{font-size:1.08rem;margin:1.3rem 0 .3rem}
p,li{max-width:68ch}
.lead{font-size:1.15rem;color:var(--muted)}
.meta{color:var(--muted);font-size:.9rem}
.sec-sub{color:var(--muted);margin:-.2rem 0 1.4rem;max-width:60ch}

/* buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:.5rem;background:var(--cta);color:var(--cta-ink);padding:.8rem 1.4rem;border-radius:999px;text-decoration:none;font-weight:700;border:0;font:inherit;font-weight:700;cursor:pointer;min-height:48px;transition:transform .15s,background .15s}
.btn:hover{background:var(--cta-hover)}
.btn:active{transform:translateY(1px) scale(.99)}
.btn:disabled{opacity:.5;cursor:not-allowed}
.btn.alt{background:transparent;color:var(--accent);box-shadow:inset 0 0 0 2px var(--accent)}
.btn.alt:hover{background:var(--soft)}
.btn.lg{font-size:1.08rem;padding:.95rem 1.7rem;min-height:54px}
.btn.block{width:100%}
.cta{display:flex;flex-wrap:wrap;gap:12px;margin:1.2rem 0}
:focus-visible{outline:3px solid var(--accent);outline-offset:2px}

/* surfaces */
.card{background:var(--panel);border:1px solid var(--line);border-radius:var(--r);padding:18px 20px;margin:16px 0}
.note{background:var(--soft);border:1px solid var(--line);border-radius:var(--r);padding:12px 16px;font-size:.95rem;margin:16px 0}
.price{font-size:2rem;font-weight:800}

/* hero */
.hero{background:radial-gradient(900px 420px at 85% -10%,var(--brand-2),transparent 70%),var(--brand);color:var(--on-brand);padding:36px 0 44px}
.hero .grid{display:grid;gap:28px;align-items:center}
@media(min-width:880px){.hero{padding:56px 0 64px}.hero .grid{grid-template-columns:1.15fr .85fr;gap:48px}}
.hero h1{color:#fff;font-size:clamp(2rem,7vw,3.3rem);margin-bottom:.8rem}
.hero h1 em{font-style:normal;color:var(--cta)}
.hero p.sub{font-size:1.15rem;color:var(--on-brand-muted);margin:0 0 1.2rem;max-width:34ch}
.hero .btn.alt{color:var(--on-brand);box-shadow:inset 0 0 0 2px rgba(255,255,255,.55)}
.hero .btn.alt:hover{background:rgba(255,255,255,.1)}
.hero .cta{margin-bottom:0}
.hero-card{background:var(--panel);color:var(--ink);border-radius:16px;padding:20px;box-shadow:var(--shadow)}
.hero-card .row{display:flex;justify-content:space-between;align-items:baseline;gap:12px;padding:12px 0;border-bottom:1px solid var(--line)}
.hero-card .row:last-of-type{border:0}
.hero-card .row b{font-size:1.05rem}
.hero-card .row .meta{display:block}
.hero-card .amt{font-size:1.9rem;font-weight:800;letter-spacing:-.02em;white-space:nowrap}
.hero-card .amt.free{color:var(--ok)}
.hero-card .btn{margin-top:10px}
.kicker{margin:0 0 .6rem;font-size:.82rem;font-weight:750;letter-spacing:.04em;text-transform:uppercase;color:var(--cta)}
.trust{margin:.2rem 0 0;max-width:42ch;font-size:.92rem;color:var(--on-brand-muted)}
.sheet{background:#fffef8;color:#1c1915;border-radius:16px;box-shadow:var(--shadow);overflow:hidden}
.sheet-bar{display:flex;justify-content:space-between;align-items:center;gap:12px;background:var(--brand);color:var(--on-brand);padding:10px 14px;font-weight:750;font-size:.92rem}
.sheet-clock{font-variant-numeric:tabular-nums;color:var(--cta);border:1px solid rgba(245,179,1,.55);border-radius:999px;padding:.15rem .65rem}
.sheet-k{margin:0;padding:12px 16px 0;font-size:.82rem;font-weight:750;letter-spacing:.03em;text-transform:uppercase;color:#6b6256}
.sheet-q{margin:6px 16px 12px;font-family:Georgia,"Iowan Old Style",Palatino,serif;font-size:1.15rem;line-height:1.35}
.sheet-opts{margin:0;padding:0 12px 8px}
.sheet-opts p{display:flex;gap:10px;align-items:center;margin:0 0 8px;padding:8px 10px;border:1px solid #e4dccb;border-radius:10px;background:#fff;max-width:none}
.sheet-opts b{display:grid;place-items:center;width:28px;height:28px;border-radius:50%;border:1.5px solid #c9bfae;font-size:.85rem;flex:none}
.sheet-opts .on{border-color:var(--accent);box-shadow:inset 0 0 0 1px var(--accent)}
.sheet-opts .on b{background:var(--accent);color:#fff;border-color:var(--accent)}
.sheet-foot{margin:0;padding:10px 16px 14px;font-size:.88rem;color:#6b6256;border-top:1px solid #efe6d6}

/* chips row (real facts) */
.facts{background:var(--panel);border-bottom:1px solid var(--line)}
.facts ul{list-style:none;margin:0;padding:14px 0;display:grid;grid-template-columns:1fr 1fr;gap:10px 14px}
@media(min-width:760px){.facts ul{grid-template-columns:repeat(4,1fr)}}
.facts li{display:flex;gap:10px;align-items:center;font-weight:650;font-size:.95rem;max-width:none;line-height:1.3}
.facts .ic{color:var(--accent);width:1.5em;height:1.5em}

/* plans */
.plans{display:grid;gap:16px;align-items:stretch}
@media(min-width:820px){.plans{grid-template-columns:1fr 1fr}}
.plan{background:var(--panel);border:1.5px solid var(--line);border-radius:16px;padding:22px;display:flex;flex-direction:column;position:relative}
.plan[hidden]{display:none}
.plan h3{margin:0 0 .2rem;font-size:1.2rem}
.plan .amt{font-size:2.6rem;font-weight:800;letter-spacing:-.03em;line-height:1.1;margin:.4rem 0 .1rem}
.plan .amt small{font-size:1rem;font-weight:600;color:var(--muted);letter-spacing:0}
.plan ul.ticks{list-style:none;padding:0;margin:14px 0;display:flex;flex-direction:column;gap:9px;flex:1 1 auto;justify-content:flex-start}
.plan ul.ticks li{flex:0 0 auto}
.plan ul.ticks li{display:flex;gap:10px;align-items:flex-start}
.plan ul.ticks .ic{color:var(--ok);margin-top:.15em}
.plan.main{border-color:var(--accent);box-shadow:var(--shadow)}
.badge{position:absolute;top:-13px;left:18px;background:var(--accent);color:var(--accent-ink);font-size:.8rem;font-weight:800;padding:.25rem .8rem;border-radius:999px}
.addon{max-width:none;margin-top:14px;padding:12px 16px;border:1.5px dashed var(--line);border-radius:var(--r);display:flex;gap:10px;align-items:flex-start;color:var(--muted);font-size:.95rem}
.addon .ic{color:var(--accent);margin-top:.2em}
.buybox{border-top:1px solid var(--line);margin-top:6px;padding-top:12px}
.waiver{display:flex;gap:10px;align-items:flex-start;margin:10px 0;font-size:.9rem;color:var(--muted)}
.waiver input{margin-top:.25rem;width:22px;height:22px;flex:none;accent-color:var(--accent)}
.err{color:var(--bad)}

/* course content grid (asymmetric: 2 wide + 4 small + 1 wide) */
.feat{display:grid;gap:14px}
@media(min-width:700px){.feat{grid-template-columns:repeat(6,1fr)}.feat .f{grid-column:span 2}.feat .f.w{grid-column:span 3}.feat .f.x{grid-column:span 6}}
.f{background:var(--panel);border:1px solid var(--line);border-radius:var(--r);padding:18px}
.f .ic{width:2.1rem;height:2.1rem;padding:.45rem;border-radius:10px;background:var(--soft);color:var(--accent);display:block;margin-bottom:10px;box-sizing:content-box;width:1.3rem;height:1.3rem}
.f h3{margin:0 0 .25rem}
.f p{margin:0;color:var(--muted);font-size:.97rem}
.f.tint{background:var(--brand);border-color:var(--brand);color:var(--on-brand)}
.f.tint p{color:var(--on-brand-muted)}
.f.tint .ic{background:rgba(255,255,255,.12);color:var(--cta)}
.langs{display:flex;flex-wrap:wrap;gap:6px;margin-top:10px}
.langs span{font-size:.82rem;font-weight:700;padding:.2rem .6rem;border-radius:999px;background:rgba(255,255,255,.12)}

/* steps */
ol.how{list-style:none;counter-reset:s;padding:0;margin:0;display:grid;gap:14px}
@media(min-width:760px){ol.how{grid-template-columns:repeat(3,1fr)}}
ol.how li{counter-increment:s;background:var(--panel);border:1px solid var(--line);border-radius:var(--r);padding:18px 18px 18px 64px;position:relative;max-width:none}
ol.how li::before{content:counter(s);position:absolute;left:16px;top:16px;width:34px;height:34px;border-radius:50%;background:var(--brand);color:var(--cta);font-weight:800;display:grid;place-items:center}
ol.how b{display:block;font-size:1.05rem;margin-bottom:2px}
ol.steps{padding-left:1.2rem}
ol.steps li{margin:.5rem 0}

/* faq */
details{border-bottom:1px solid var(--line);padding:.2rem 0}
summary{cursor:pointer;font-weight:650;padding:.8rem 2rem .8rem 0;min-height:48px;position:relative;list-style:none}
summary::-webkit-details-marker{display:none}
summary::after{content:"+";position:absolute;right:4px;top:.6rem;font-size:1.4rem;color:var(--accent);font-weight:400}
details[open] summary::after{content:"\2212"}
details p{margin:0 0 .9rem;color:var(--muted)}

/* closing band */
.band{background:var(--brand);color:var(--on-brand);border-radius:20px;padding:28px 22px;margin-top:2.6rem;display:grid;gap:10px}
.band h2{margin:0;color:#fff}
.band p{margin:0;color:var(--on-brand-muted)}
.band .btn.alt{color:var(--on-brand);box-shadow:inset 0 0 0 2px rgba(255,255,255,.55)}
@media(min-width:760px){.band{padding:36px;grid-template-columns:1fr auto;align-items:center}.band .cta{margin:0}}

/* article pages */
.crumbs{font-size:.88rem;color:var(--muted);margin:0 0 .6rem}
.crumbs a{color:var(--muted)}
.facts-box{background:var(--soft);border:1px solid var(--line);border-left:5px solid var(--accent);border-radius:var(--r);padding:14px 18px;margin:18px 0}
.facts-box h2{margin:0 0 .4rem;font-size:1.05rem}
.facts-box ul{margin:0;padding-left:1.1rem}
.toc{background:var(--panel);border:1px solid var(--line);border-radius:var(--r);padding:12px 18px;margin:18px 0}
.toc b{display:block;margin-bottom:.2rem}
.toc ol{margin:0;padding-left:1.2rem}
.toc a{display:inline-block;padding:.2rem 0}
.article h2{margin-top:2.2rem}
.related{display:grid;gap:10px;margin:14px 0}
@media(min-width:700px){.related{grid-template-columns:repeat(3,1fr)}}
.related a{display:block;background:var(--panel);border:1px solid var(--line);border-radius:var(--r);padding:14px 16px;text-decoration:none;color:var(--ink);font-weight:650}
.related a small{display:block;font-weight:400;color:var(--muted);margin-top:2px}
.related a:hover{border-color:var(--accent)}
table{width:100%;border-collapse:collapse;font-size:.95rem;margin:.6rem 0 1rem}
th,td{text-align:left;padding:.6rem .5rem;border-bottom:1px solid var(--line);vertical-align:top}
th{color:var(--muted);font-weight:600}
@media(max-width:600px){table{display:block;overflow-x:auto}}

/* footer */
footer.site{border-top:1px solid var(--line);padding:26px 0 90px;color:var(--muted);font-size:.9rem;background:var(--panel)}
footer.site p{margin:.3rem 0}
footer.site a{margin-right:14px;color:var(--muted);display:inline-block;padding:.3rem 0}

/* sticky mobile CTA */
.sticky{position:fixed;left:0;right:0;bottom:0;z-index:30;background:var(--panel);border-top:1px solid var(--line);padding:10px 14px calc(10px + env(safe-area-inset-bottom));display:flex;gap:10px;align-items:center;box-shadow:0 -6px 20px -10px rgba(0,0,0,.35)}
.sticky .btn{flex:1;min-height:48px;padding:.6rem 1rem}
.sticky .p{font-weight:800;white-space:nowrap}
.sticky .p small{display:block;font-weight:500;color:var(--muted);font-size:.72rem}
@media(min-width:880px){.sticky{display:none}footer.site{padding-bottom:40px}}

/* cookie banner (consent.js) sits above the sticky bar */
#cc{position:fixed;left:0;right:0;bottom:0;background:var(--panel);border-top:1px solid var(--line);padding:10px 16px;z-index:50;box-shadow:0 -2px 12px rgba(0,0,0,.18)}
#cc .in{max-width:760px;margin:0 auto;font-size:.85rem;line-height:1.45}
#cc .row{display:flex;gap:8px;margin-top:8px}
#cc .row button{flex:1}
@media(max-width:600px){#cc{padding:8px 12px}#cc .in{font-size:.78rem;line-height:1.35}#cc button{min-height:40px;padding:.4rem .6rem;font-size:.85rem}}
#cc button{font:inherit;padding:.6rem 1rem;border-radius:999px;min-height:44px;cursor:pointer;border:1.5px solid var(--accent);background:transparent;color:var(--accent);font-weight:600}
#cc button.y{background:var(--accent);color:var(--accent-ink)}
main a:not(.btn){text-decoration:underline;text-underline-offset:2px}
.related a,ol.toc a{text-decoration:none}

/* theme toggle (theme.js) */
.theme-toggle{display:inline-flex;align-items:center;gap:6px;min-height:44px;padding:.45rem .7rem;border-radius:999px;border:1.5px solid var(--line);background:transparent;color:var(--ink);font:inherit;font-size:.9rem;font-weight:600;cursor:pointer}
.theme-toggle:hover{background:var(--soft)}
.theme-toggle:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
@media(max-width:560px){.theme-toggle .tl{display:none}.theme-toggle{padding:.45rem .6rem}}
/* Shop and basket (15.10.2026): period choice, Buy now / Add to basket, basket bar (bottom left; the chat sits bottom right) */
.periods{display:grid;grid-template-columns:repeat(3,1fr);gap:.5rem;margin:.6rem 0 1rem}
.period{display:flex;flex-direction:column;align-items:center;gap:.1rem;min-height:56px;padding:.5rem;border-radius:12px;border:2px solid var(--line);background:var(--panel);color:var(--ink);font:inherit;font-weight:700;cursor:pointer}
.period small{font-weight:400;color:var(--muted)}
.period[aria-pressed=true]{border-color:var(--accent);background:var(--soft)}
.period:focus-visible{outline:3px solid var(--accent);outline-offset:2px}
.buyrow{display:grid;grid-template-columns:1fr;gap:.5rem;margin:.5rem 0}
@media (min-width:520px){.buyrow{grid-template-columns:1fr 1fr}}
.basket-open.bump{transform:scale(1.08)}
.basket-panel{position:fixed;right:16px;left:auto;top:72px;width:min(26rem,calc(100vw - 32px));z-index:61;max-width:26rem;max-height:75vh;overflow:auto;padding:1.2rem;border-radius:18px;background:var(--panel);color:var(--ink);border:1px solid var(--line);box-shadow:var(--shadow)}
.basket-panel h2{margin:0 0 .6rem;font-size:1.3rem}
.basket-items{list-style:none;margin:0 0 .8rem;padding:0}
.basket-items li{display:grid;grid-template-columns:1fr auto;gap:.2rem .6rem;align-items:center;padding:.6rem 0;border-bottom:1px solid var(--line)}
.basket-rm{grid-column:1/-1;justify-self:start;background:none;border:0;padding:0;color:var(--accent);text-decoration:underline;font:inherit;font-size:.9rem;cursor:pointer}
.basket-total{display:flex;align-items:baseline;gap:.5rem;font-size:1.1rem}
.basket-panel .btn{margin-top:.5rem}
.basket-panel h2:focus{outline:none}
/* Basket button lives in the header, top right (founder 15.10.2026) */
.basket-open{position:relative;display:inline-flex;align-items:center;justify-content:center;width:44px;height:44px;margin-left:4px;border-radius:999px;border:1.5px solid var(--line);background:transparent;color:var(--ink);cursor:pointer;transition:transform .15s}
.basket-open:hover{background:var(--soft)}
.basket-open .ic{width:22px;height:22px;fill:none;stroke:currentColor;stroke-width:2;stroke-linecap:round;stroke-linejoin:round}
.basket-count{position:absolute;top:-4px;right:-4px;min-width:20px;height:20px;padding:0 5px;border-radius:999px;background:var(--cta);color:var(--cta-ink);font-size:.75rem;font-weight:800;line-height:20px;text-align:center}
.basket-count[hidden]{display:none}
.basket-open.bump{transform:scale(1.15)}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
header.site a.brand{white-space:nowrap}
/* Footer: columns of links, company details on /contact.html */
footer.site .f-grid{display:grid;grid-template-columns:1.4fr repeat(4,1fr);gap:24px 28px;margin-bottom:22px}
footer.site .f-brand .brand{color:var(--ink);font-weight:800;text-decoration:none;display:inline-flex;align-items:center;gap:8px;margin:0}
footer.site .f-brand p{max-width:30ch;margin:.6rem 0 0;line-height:1.45}
footer.site nav{display:flex;flex-direction:column;align-items:flex-start}
footer.site nav a{margin:0;padding:.35rem 0;text-decoration:none;color:var(--muted)}
footer.site nav a:hover{color:var(--ink);text-decoration:underline}
footer.site .f-h{margin:0 0 .3rem;font-size:.8rem;font-weight:700;letter-spacing:.04em;text-transform:uppercase;color:var(--ink)}
footer.site .f-bottom{border-top:1px solid var(--line);padding-top:16px;font-size:.85rem;max-width:none}
footer.site .f-bottom a{margin:0;padding:0}
@media(max-width:880px){footer.site .f-grid{grid-template-columns:1fr 1fr}footer.site .f-brand{grid-column:1/-1}}
/* Home: "Watch demo" video dialog */
.demo-open .ic{width:18px;height:18px;fill:currentColor;stroke:none;vertical-align:-3px}
.demo-dlg{padding:0;border:0;background:transparent;max-width:min(960px,94vw);width:100%}
.demo-dlg::backdrop{background:rgba(0,0,0,.78)}
.demo-in{position:relative;background:#0c1413;border-radius:16px;overflow:hidden;box-shadow:0 30px 80px -20px rgba(0,0,0,.8)}
.demo-in video{display:block;width:100%;height:auto;aspect-ratio:16/9;background:#0c1413}
.demo-note{margin:0;padding:10px 16px;color:#9fb5b1;font-size:.9rem;max-width:none}
.demo-x{position:absolute;top:10px;right:10px;z-index:2;width:44px;height:44px;border-radius:50%;border:0;background:rgba(0,0,0,.6);color:#fff;font-size:28px;line-height:1;cursor:pointer}
.demo-x:focus-visible{outline:3px solid var(--accent);outline-offset:2px}