/* Layout: app shell — floating sidebar for browsing, rounded hero card, feature cards, then colored lesson cards per section. */
:root{
  --page:#ebebea; --panel:#ffffff; --soft:#f4f4f2; --ink:#141414; --ink-2:#6b6b69; --ink-3:#9c9c99; --line:#e2e2df;
  --dark:#141414; --dark-ink:#ffffff; --accent:#ff5a1f; --free:#e5f4e3; --free-ink:#2f7a2a; --ai:#ecebfd; --ai-ink:#5145c9; --lock:#b2481d;
  --shadow:0 1px 2px rgba(0,0,0,.05),0 6px 20px rgba(0,0,0,.05);
  --f:"Inter","Helvetica Neue",Arial,sans-serif;
}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){
  --page:#0d0d0d; --panel:#181818; --soft:#202020; --ink:#f0f0ee; --ink-2:#a5a5a1; --ink-3:#73736f; --line:#2b2b2a;
  --dark:#f0f0ee; --dark-ink:#141414; --free:#1d3320; --free-ink:#8fd889; --ai:#25223f; --ai-ink:#b3abff; --lock:#f08a5d;
  --shadow:0 1px 2px rgba(0,0,0,.4); color-scheme:dark}}
:root[data-theme="dark"]{
  --page:#0d0d0d; --panel:#181818; --soft:#202020; --ink:#f0f0ee; --ink-2:#a5a5a1; --ink-3:#73736f; --line:#2b2b2a;
  --dark:#f0f0ee; --dark-ink:#141414; --free:#1d3320; --free-ink:#8fd889; --ai:#25223f; --ai-ink:#b3abff; --lock:#f08a5d;
  --shadow:0 1px 2px rgba(0,0,0,.4); color-scheme:dark}

*{box-sizing:border-box}
html{scroll-padding-top:16px}
body{margin:0;background:var(--page);color:var(--ink);font-family:var(--f);font-size:14px;line-height:1.5;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
button{font:inherit;color:inherit}
[hidden]{display:none!important}
:focus-visible{outline:2px solid var(--ink);outline-offset:2px}
.cap{font-size:11px;font-weight:600;letter-spacing:.08em;text-transform:uppercase}
.muted{color:var(--ink-2)}

/* sidebar */
.side{position:fixed;top:16px;bottom:16px;left:16px;width:236px;background:var(--panel);border-radius:22px;box-shadow:var(--shadow);display:flex;flex-direction:column;padding:22px 10px 12px;z-index:30;overflow:hidden}
.side .brand{display:flex;align-items:center;gap:8px;font-weight:700;font-size:16px;letter-spacing:-.02em;padding:0 12px 18px}
.brand i{width:24px;height:24px;font-size:9px!important;font-weight:700;border-radius:50%;background:var(--ink);display:grid;place-items:center;color:var(--panel);font-style:normal;font-size:11px}
.nav{flex:1;overflow-y:auto;scrollbar-width:none;margin:0 -2px;padding:0 2px}
.nav h6{margin:16px 12px 6px;font-size:11px;font-weight:500;letter-spacing:.1em;text-transform:uppercase;color:var(--ink-3)}
.nav a{display:flex;align-items:center;gap:10px;padding:7px 10px 7px 12px;border-radius:11px;color:var(--ink-2);font-size:13.5px;line-height:1.3}
.nav a:hover{background:var(--soft);color:var(--ink)}
.nav a[aria-current="page"]{background:var(--panel);color:var(--ink);font-weight:500;box-shadow:0 0 0 1px var(--line),0 2px 6px rgba(0,0,0,.06)}
.nav a svg{flex:none;width:16px;height:16px}
.nav a .n{flex:none;width:16px;font-size:10.5px;font-weight:600;color:var(--ink-3);font-variant-numeric:tabular-nums}
.nav a .t{flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.nav a .c{font-size:11.5px;color:var(--ink-3);font-variant-numeric:tabular-nums}
.nav a .dot{width:6px;height:6px;border-radius:50%;background:var(--accent)}
.nav a .pill{font-size:9.5px;padding:2px 7px}
.side-foot{display:flex;flex-direction:column;gap:8px;padding:12px 4px 0;border-top:1px solid var(--line);margin-top:8px}
.seg{display:grid;grid-template-columns:1fr 1fr;background:var(--soft);border-radius:999px;padding:3px}
.seg button{border:0;background:none;border-radius:999px;padding:6px 0;cursor:pointer;font-size:12.5px;color:var(--ink-2)}
.seg button[aria-pressed="true"]{background:var(--panel);color:var(--ink);font-weight:500;box-shadow:0 1px 3px rgba(0,0,0,.1)}
.side-links{display:flex;justify-content:space-between;padding:4px 8px 0;font-size:12.5px;color:var(--ink-2)}
.side-links a:hover{color:var(--ink)}

.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;border-radius:999px;padding:12px 22px;font-size:14px;font-weight:500;cursor:pointer;border:1px solid var(--line);background:var(--panel);color:var(--ink);box-shadow:0 1px 2px rgba(0,0,0,.05);white-space:nowrap}
.btn:hover{background:var(--soft)}
.btn.dark{background:var(--dark);color:var(--dark-ink);border-color:var(--dark);box-shadow:0 6px 16px rgba(0,0,0,.18)}
.btn.dark:hover{opacity:.9}
.btn.sm{padding:8px 15px;font-size:13px}
.pill{display:inline-flex;align-items:center;gap:5px;border-radius:999px;padding:3px 9px;font-size:11px;font-weight:600;letter-spacing:.06em;text-transform:uppercase;background:var(--soft);color:var(--ink-2);white-space:nowrap}
.pill.free{background:var(--free);color:var(--free-ink)}
.pill.ai{background:var(--ai);color:var(--ai-ink)}
.pill.line{background:var(--panel);border:1px solid var(--line);color:var(--ink)}
.pill .d{width:6px;height:6px;border-radius:50%;background:var(--accent)}

/* main column */
.main{margin-left:268px;padding:16px 16px 32px 0;min-width:0}
.mbar{display:none}

.hero{background:var(--panel);border-radius:30px;padding:8px;box-shadow:var(--shadow)}
.hero-in{background:var(--soft);border-radius:24px;padding:clamp(28px,5vw,64px) clamp(24px,4vw,56px);display:grid;grid-template-columns:minmax(0,1.05fr) minmax(0,1fr);gap:40px;align-items:center;min-height:500px;overflow:hidden}
.hero .pill.line{white-space:normal;line-height:1.4}
.hero h1{margin:22px 0 0;font-size:clamp(40px,4.6vw,68px);font-weight:500;line-height:1.02;letter-spacing:-.035em;text-wrap:balance}
.hero h1 span{color:var(--ink-3)}
.hero p{margin:22px 0 0;max-width:46ch;font-size:16px;line-height:1.65;color:var(--ink-2)}
.hero p b{color:var(--ink);font-weight:600}
.hero .ctas{display:flex;gap:12px;flex-wrap:wrap;margin-top:30px}
.stack{position:relative;aspect-ratio:1.3;width:100%;max-width:640px;justify-self:end}
.stack{isolation:isolate}
.stack .glow{position:absolute;inset:6%;width:88%;height:88%;object-fit:cover;filter:blur(42px) saturate(1.6);opacity:.9;border-radius:50px;z-index:-1}
.stack > div{position:absolute;border-radius:24px}
.stack .s1{inset:2% 0 18% 12%;transform:rotate(4deg)}
.stack .s2{inset:16% 18% 4% 0;transform:rotate(-4deg)}
.stack .s3{inset:9% 5% 12% 6%;padding:12px;transform:rotate(-1deg);background:rgba(255,255,255,.4)}
.mosaic{width:100%;height:100%;background:rgba(255,255,255,.35);border-radius:14px;display:grid;grid-template-columns:repeat(3,1fr);grid-template-rows:repeat(2,1fr);gap:6px;padding:6px}
.mosaic img{width:100%;height:100%;object-fit:cover;display:block;border-radius:8px}

.features{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px;margin-top:16px}
.fcard{background:var(--panel);border-radius:24px;padding:22px 22px 20px;box-shadow:var(--shadow);display:flex;flex-direction:column;gap:6px;min-height:186px}
.fcard .tags{display:flex;gap:8px;align-items:center;margin-bottom:10px}
.fcard h3{margin:0;font-size:17px;font-weight:500;letter-spacing:-.01em}
.fcard p{margin:0;color:var(--ink-2);line-height:1.6}
.fcard a.go{margin-top:auto;padding-top:14px;font-weight:500;font-size:13.5px}
.fcard a.go:hover{text-decoration:underline;text-underline-offset:3px}

/* section rows */
.shead{display:flex;justify-content:space-between;align-items:flex-end;gap:20px;margin:56px 4px 18px}
.shead .k{display:flex;align-items:center;gap:8px;font-size:11.5px;font-weight:500;letter-spacing:.1em;text-transform:uppercase;color:var(--ink-2)}
.shead h2{margin:8px 0 0;font-size:clamp(24px,2.6vw,34px);font-weight:500;letter-spacing:-.025em;line-height:1.15;text-wrap:balance}
.shead h2 span{color:var(--ink-3)}
.lgrid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}
.lcard{display:flex;flex-direction:column;gap:12px;min-width:0}
.lart{position:relative;aspect-ratio:16/11;border-radius:24px;background:var(--soft);overflow:hidden;box-shadow:var(--shadow);transition:transform .25s ease;isolation:isolate}
.lart .bg{position:absolute;inset:-25%;width:150%;height:150%;object-fit:cover;filter:blur(30px) saturate(1.5);transform:scale(1.05);z-index:-1}
.lart::after{content:"";position:absolute;inset:0;border-radius:inherit;pointer-events:none;z-index:3;
  background:linear-gradient(155deg,rgba(255,255,255,.38),rgba(255,255,255,.06) 42%,rgba(255,255,255,.14));
  box-shadow:inset 0 1px 0 rgba(255,255,255,.75),inset 0 0 0 1px rgba(255,255,255,.35),inset 0 -1px 0 rgba(255,255,255,.2)}
.lcard:hover .lart{transform:translateY(-3px)}
.glass{background:rgba(255,255,255,.3);-webkit-backdrop-filter:blur(18px) saturate(1.8);backdrop-filter:blur(18px) saturate(1.8);border:1px solid rgba(255,255,255,.6);box-shadow:inset 0 1px 0 rgba(255,255,255,.85),0 8px 24px rgba(0,0,0,.12)}
.lart .pill{position:absolute;top:14px;left:14px;z-index:4;background:rgba(255,255,255,.55);color:#141414;-webkit-backdrop-filter:blur(16px) saturate(1.8);backdrop-filter:blur(16px) saturate(1.8);border:1px solid rgba(255,255,255,.7);box-shadow:inset 0 1px 0 rgba(255,255,255,.9)}
.frame{position:absolute;left:7%;right:7%;top:20%;bottom:-1px;border-radius:16px 16px 0 0;padding:8px 8px 0;border-bottom:0;z-index:2;display:grid;gap:5px;grid-auto-flow:column;grid-auto-columns:1fr}
.frame img{width:100%;height:100%;object-fit:cover;display:block;border-radius:9px 9px 0 0;background:rgba(255,255,255,.4)}
.lmeta{padding:0 4px;display:flex;justify-content:space-between;gap:12px;align-items:baseline}
.lmeta b{font-weight:500;font-size:15px;letter-spacing:-.01em}
.lmeta span{color:var(--ink-3);font-size:12.5px;white-space:nowrap}

/* page header (section / lesson views) */
.phead{background:var(--panel);border-radius:28px;padding:clamp(24px,4vw,44px);box-shadow:var(--shadow);display:flex;flex-direction:column;gap:14px}
.crumb{display:flex;gap:8px;align-items:center;color:var(--ink-3);font-size:13px;flex-wrap:wrap}
.crumb a:hover{color:var(--ink)}
.phead h1{margin:0;font-size:clamp(34px,4vw,56px);font-weight:500;letter-spacing:-.035em;line-height:1.02;text-wrap:balance}
.phead h1 span{color:var(--ink-3)}
.phead .row{display:flex;gap:8px;flex-wrap:wrap;align-items:center}
.chips{display:flex;gap:6px;flex-wrap:wrap;margin-top:4px}
.chip{border:1px solid var(--line);background:var(--panel);border-radius:999px;padding:6px 13px;cursor:pointer;font-size:13px;color:var(--ink-2);white-space:nowrap}
.chip:hover{color:var(--ink);background:var(--soft)}
.chip[aria-current="true"]{background:var(--dark);color:var(--dark-ink);border-color:var(--dark)}

.phead + .xgrid,.phead + .lgrid{margin-top:16px}
.lhead{display:flex;justify-content:space-between;align-items:flex-end;gap:16px;flex-wrap:wrap;margin:44px 4px 16px}
.lhead h2{margin:4px 0 0;font-size:clamp(24px,2.6vw,32px);font-weight:500;letter-spacing:-.025em;line-height:1.1}
.lhead .row{display:flex;gap:8px;flex-wrap:wrap;align-items:center}

/* example cards */
.xgrid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px;align-items:start}
.xcard{background:var(--panel);border-radius:22px;padding:10px 10px 18px;box-shadow:var(--shadow);display:flex;flex-direction:column;gap:14px;min-width:0}
.xtop{display:flex;justify-content:space-between;align-items:center;padding:4px 6px 0}
.fav{border:0;background:none;cursor:pointer;width:30px;height:30px;border-radius:50%;display:grid;place-items:center;color:var(--ink-3)}
.fav:hover{background:var(--soft);color:var(--ink)}
.fav[aria-pressed="true"]{color:var(--accent)}
.fav[aria-pressed="true"] path{fill:currentColor}
.media{position:relative;aspect-ratio:4/3;overflow:hidden;background:var(--soft);border-radius:14px;--pos:50%;user-select:none}
.media img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;display:block}
.media .after{clip-path:inset(0 0 0 var(--pos))}
.media .handle{position:absolute;top:0;bottom:0;left:var(--pos);width:2px;margin-left:-1px;background:#fff;pointer-events:none;box-shadow:0 0 0 1px rgba(0,0,0,.12)}
.media .handle::after{content:"";position:absolute;top:50%;left:50%;width:30px;height:30px;margin:-15px 0 0 -15px;border-radius:50%;background:#fff;box-shadow:0 1px 6px rgba(0,0,0,.25);
  background-image:linear-gradient(90deg,transparent 9px,#141414 9px,#141414 11px,transparent 11px,transparent 19px,#141414 19px,#141414 21px,transparent 21px)}
.media input[type=range]{position:absolute;inset:0;width:100%;height:100%;opacity:0;margin:0;cursor:ew-resize}
.media .lab{position:absolute;bottom:9px;font-size:10.5px;font-weight:600;letter-spacing:.06em;text-transform:uppercase;background:rgba(255,255,255,.94);color:#141414;padding:3px 8px;border-radius:999px;pointer-events:none;max-width:46%;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.media .lab.l{left:9px}.media .lab.r{right:9px}
.media .zoom{position:absolute;top:9px;right:9px;width:30px;height:30px;border-radius:50%;border:0;background:rgba(255,255,255,.94);color:#141414;cursor:zoom-in;z-index:2;display:grid;place-items:center}
.single .handle,.single .after,.single input,.single .lab.r{display:none}
.single img.before{cursor:zoom-in}
.thumbs{display:flex;gap:6px;flex-wrap:wrap;padding:0 4px;margin-top:-4px}
.thumbs button{width:46px;height:46px;padding:0;border:0;border-radius:9px;background:var(--soft);cursor:pointer;overflow:hidden;opacity:.55}
.thumbs button[aria-pressed="true"]{opacity:1;outline:2px solid var(--ink);outline-offset:1px}
.thumbs img{width:100%;height:100%;object-fit:cover;display:block}
.xcard h3{margin:0;padding:0 8px;font-weight:500;font-size:16px;line-height:1.3;letter-spacing:-.01em}
.prompts{display:flex;flex-direction:column;gap:10px;padding:0 4px}
.prompts > div{background:var(--soft);border-radius:14px;padding:11px 12px}
.pl{font-size:10.5px;font-weight:600;letter-spacing:.08em;text-transform:uppercase;margin-bottom:5px;display:flex;justify-content:space-between;gap:8px;align-items:center}
.pt{margin:0;font-size:13px;line-height:1.6;color:var(--ink-2);white-space:pre-wrap;overflow-wrap:anywhere;max-height:280px;overflow:auto}
.locked .pt{filter:blur(4px);user-select:none;max-height:7.9em;overflow:hidden}
.copy{border:1px solid var(--line);background:var(--panel);border-radius:999px;padding:3px 10px;cursor:pointer;font-size:10.5px;font-weight:600;letter-spacing:.08em;text-transform:uppercase}
.unlock{margin:0 8px;align-self:flex-start;border:0;background:none;padding:0;cursor:pointer;font-weight:500;font-size:13.5px}
.unlock:hover{text-decoration:underline;text-underline-offset:3px}
.empty{grid-column:1/-1;background:var(--panel);border-radius:22px;padding:60px 24px;text-align:center;color:var(--ink-2)}

/* how + pricing */
.cards3{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}
.ccard{background:var(--panel);border-radius:24px;padding:24px;box-shadow:var(--shadow);display:flex;flex-direction:column;gap:10px}
.ccard h4{margin:0;font-size:18px;font-weight:500;letter-spacing:-.015em}
.ccard p{margin:0;color:var(--ink-2);line-height:1.6}
.price{font-size:46px;font-weight:500;letter-spacing:-.04em;line-height:1;margin:6px 0;font-variant-numeric:tabular-nums}
.price small{font-size:14px;color:var(--ink-3);letter-spacing:0;font-weight:400}
.plan ul{list-style:none;margin:0 0 8px;padding:0;display:flex;flex-direction:column;gap:7px;color:var(--ink-2)}
.plan ul li::before{content:"✓  ";color:var(--ink)}
.plan .btn{margin-top:auto}
.plan.best{background:var(--dark);color:var(--dark-ink)}
.plan.best p,.plan.best ul,.plan.best .price small{color:color-mix(in srgb,var(--dark-ink) 65%,transparent)}
.plan.best ul li::before{color:var(--dark-ink)}
.plan.best .btn{background:var(--dark-ink);color:var(--dark);border-color:var(--dark-ink)}

footer{margin-top:56px;padding:22px 4px 0;border-top:1px solid var(--line);display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap;color:var(--ink-3);font-size:12.5px}
footer a:hover{color:var(--ink)}

dialog{border:0;padding:0;background:transparent;max-width:calc(100vw - 32px);max-height:calc(100dvh - 32px)}
dialog::backdrop{background:rgba(10,10,10,.88)}
dialog img{display:block;max-width:calc(100vw - 32px);max-height:calc(100dvh - 80px);width:auto;height:auto;border-radius:8px}
dialog p{margin:8px 0 0;color:#eee;font-size:11px;font-weight:600;letter-spacing:.08em;text-transform:uppercase}
.close{position:fixed;top:calc(12px + env(safe-area-inset-top,0px));right:max(12px,env(safe-area-inset-right,0px));width:38px;height:38px;border-radius:50%;border:0;background:#fff;color:#141414;cursor:pointer;font-size:20px}
.toast{position:fixed;left:50%;bottom:calc(20px + env(safe-area-inset-bottom,0px));transform:translateX(-50%);background:var(--dark);color:var(--dark-ink);padding:10px 18px;border-radius:999px;font-size:13px;z-index:50;max-width:calc(100% - 32px)}
.scrim{position:fixed;inset:0;background:rgba(0,0,0,.35);z-index:25}

@media (max-width:1180px){.lgrid,.xgrid{grid-template-columns:repeat(2,minmax(0,1fr))}.hero-in{grid-template-columns:minmax(0,1fr);min-height:0}.stack{justify-self:center;max-width:520px}}
@media (max-width:900px){
  .main{margin-left:0;padding:0 16px 28px;padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px))}
  .mbar{display:flex;position:sticky;top:0;z-index:20;align-items:center;justify-content:space-between;background:var(--page);padding:calc(12px + env(safe-area-inset-top,0px)) 0 12px}
  .mbar .brand{display:flex;align-items:center;gap:8px;font-weight:700;font-size:16px;letter-spacing:-.02em}
  .side{top:8px;bottom:8px;left:8px;transform:translateX(calc(-100% - 20px));transition:transform .25s ease}
  .side.open{transform:none}
  .features,.cards3{grid-template-columns:1fr}
  .fcard{min-height:0}
}
@media (max-width:620px){
  .lgrid,.xgrid{grid-template-columns:1fr}
  .hero-in{padding:28px 20px}
  .shead{flex-direction:column;align-items:flex-start;margin-top:44px}
}
@media (prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}

.nav a .c{margin-left:auto}
.side-links a.lang{font-weight:500;color:var(--ink)}
.phead .lead{margin:0;max-width:70ch;color:var(--ink-2);font-size:15.5px;line-height:1.65}
.prose{background:var(--panel);border-radius:24px;padding:24px 26px;box-shadow:var(--shadow);margin-top:16px;display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:28px}
.prose h2{margin:0 0 8px;font-size:18px;font-weight:500;letter-spacing:-.015em}
.prose ol{margin:0;padding-left:20px;color:var(--ink-2);line-height:1.7}
.prose p{margin:0;color:var(--ink-2);line-height:1.7}
.skel{display:flex;flex-direction:column;gap:7px;padding:4px 0 2px}
.skel i{display:block;height:9px;border-radius:5px;background:color-mix(in srgb,var(--ink) 10%,transparent)}
.skel i:nth-child(2){width:92%}.skel i:nth-child(3){width:78%}.skel i:nth-child(4){width:55%}
.locked-note{display:flex;justify-content:space-between;align-items:center;gap:10px;padding:0 8px;flex-wrap:wrap}
.locked-note a{font-weight:500;font-size:13.5px}.locked-note a:hover{text-decoration:underline;text-underline-offset:3px}
.pt.z{margin-top:8px;padding-top:8px;border-top:1px dashed var(--line);color:var(--ink-3)}
.faq{display:flex;flex-direction:column;gap:8px}
.faq details{background:var(--panel);border-radius:18px;padding:16px 20px;box-shadow:var(--shadow)}
.faq summary{cursor:pointer;font-weight:500;font-size:15px}
.faq details p{margin:10px 0 0;color:var(--ink-2);line-height:1.65}
.cta{background:var(--dark);color:var(--dark-ink);border-radius:28px;padding:clamp(26px,4vw,44px);margin-top:56px;display:flex;justify-content:space-between;align-items:center;gap:24px;flex-wrap:wrap}
.cta h2{margin:0;font-size:clamp(24px,2.6vw,32px);font-weight:500;letter-spacing:-.025em}
.cta p{margin:8px 0 0;max-width:62ch;color:color-mix(in srgb,var(--dark-ink) 68%,transparent);line-height:1.6}
.cta .btn{background:var(--dark-ink);color:var(--dark);border-color:var(--dark-ink)}
.lblock[hidden]{display:none}.lblock .lhead{margin-top:40px}.chip .cn{color:var(--ink-3);font-size:11.5px;margin-left:2px}.chip[aria-current="true"] .cn{color:inherit;opacity:.6}
.xcard h3 a:hover{text-decoration:underline;text-underline-offset:3px}
@media (max-width:900px){.prose{grid-template-columns:1fr}}