/* Shared look for the three "How it works" tutorial pages (how-photo / how-video / how-listing).
   Tokens: DESIGN.md. Engine: how.js. Everything on a scene is a pure function of scroll progress. */
:root{--violet:#6d28d9;--press:#5b21b6;--soft:#f1ebfc;--paper:#f6f6fb;--surface:#fff;--sunken:#eeeef5;--hair:#e5e4ef;--ink:#18161f;--muted:#6b6a7d;--ok:#047857;--warn:#8a5a00;color-scheme:light}
@media(prefers-color-scheme:dark){:root{--violet:#8b5cf6;--press:#a78bfa;--soft:rgba(139,92,246,.16);--paper:#0e0c15;--surface:#171420;--sunken:#201c2c;--hair:rgba(255,255,255,.10);--ink:#f3f1fa;--muted:#9c97ad;--ok:#5fc9a3;--warn:#e0b155;color-scheme:dark}}
*{box-sizing:border-box}
html{scroll-behavior:auto}
body{margin:0;background:var(--paper);color:var(--ink);font:400 15px/1.5 Archivo,system-ui,sans-serif;-webkit-font-smoothing:antialiased;overflow-x:hidden}
img,video{max-width:100%;display:block}
button{font:inherit;cursor:pointer}
a{color:var(--violet)}

/* ---------- hero + sections ---------- */
.wrap{max-width:1080px;margin:0 auto;padding:0 16px}
.top{position:sticky;top:0;z-index:50;background:color-mix(in srgb,var(--paper) 90%,transparent);backdrop-filter:blur(8px);border-bottom:1px solid var(--hair)}
.top .wrap{display:flex;align-items:center;gap:12px;height:52px}
.brand{font-weight:700;letter-spacing:.04em;color:var(--ink);text-decoration:none;display:inline-block;padding:14px 4px}
.top nav{display:flex;gap:2px;margin-left:auto;flex-wrap:wrap}
.top nav a{font-size:13px;font-weight:500;color:var(--muted);text-decoration:none;padding:6px 10px;border-radius:4px}
.top nav a[aria-current]{color:var(--ink);background:var(--surface);border:1px solid var(--hair)}
.cta{display:inline-block;background:var(--violet);color:#fff!important;font-weight:700;letter-spacing:.02em;padding:12px 20px;border-radius:10px;text-decoration:none;border:0}
.cta:hover{background:var(--press)}
.hero{padding:56px 0 40px;text-align:center}
.hero h1{font-size:clamp(32px,6.5vw,56px);line-height:1.06;letter-spacing:-.03em;font-weight:600;margin:0 0 14px}
.hero p{font-size:18px;color:var(--muted);max-width:560px;margin:0 auto 24px}
.hero .down{display:block;margin:28px auto 0;color:var(--muted);font-size:13px}
.hero .down b{display:block;font-size:22px;animation:bob 1.6s ease-in-out infinite}
@keyframes bob{50%{transform:translateY(6px)}}
.chips{display:flex;flex-wrap:wrap;gap:8px;justify-content:center;margin-top:18px}
.chip{background:var(--soft);color:var(--violet);border-radius:999px;padding:5px 12px;font-size:13px;font-weight:600}
.plain{padding:56px 0}
.plain h2,.h2{font-size:clamp(24px,4vw,34px);letter-spacing:-.02em;font-weight:600;margin:0 0 8px}
.lead{color:var(--muted);margin:0 0 22px;max-width:640px}
.note{font-size:12.5px;color:var(--muted)}
footer a{display:inline-block;padding:12px 8px}
footer{padding:24px 0 96px;text-align:center;color:var(--muted);font-size:13px}
.sticky-cta{position:fixed;left:0;right:0;bottom:0;z-index:40;display:flex;gap:12px;align-items:center;justify-content:center;padding:10px 16px;background:color-mix(in srgb,var(--surface) 94%,transparent);border-top:1px solid var(--hair);transform:translateY(110%);transition:transform .3s}
.sticky-cta.on{transform:none}
.sticky-cta a.s{font-size:13px;color:var(--muted);padding:14px 8px}

/* ---------- chapter rail ---------- */
.rail{position:fixed;z-index:35;display:flex;gap:6px}
.rail a{display:block;width:10px;height:10px;border-radius:50%;background:var(--hair);position:relative;text-decoration:none;overflow:visible}
.rail a.on{background:var(--violet)}
.rail a span{position:absolute;white-space:nowrap;font-size:11px;font-weight:600;color:var(--muted);opacity:0;pointer-events:none;transition:opacity .2s}
.rail a.on span,.rail a:hover span,.rail a:focus-visible span{opacity:1}
@media(min-width:900px){.rail{left:18px;top:50%;transform:translateY(-50%);flex-direction:column;gap:14px}.rail a span{left:18px;top:-3px}}
@media(max-width:899px){.rail{top:52px;left:0;right:0;justify-content:center;padding:6px;background:color-mix(in srgb,var(--paper) 90%,transparent)}.rail a span{display:none}}

/* ---------- pinned scene ---------- */
.scene{position:relative;overflow-x:clip}
.stage{position:sticky;top:80px;height:calc(100svh - 80px);display:flex;flex-direction:column;align-items:center;justify-content:center;gap:8px;padding:0 12px 76px}
@media(min-width:900px){.stage{top:52px;height:calc(100svh - 52px)}}
.cap{min-height:2.4em;font-size:clamp(20px,3.2vw,28px);font-weight:600;letter-spacing:-.02em;text-align:center;max-width:720px;transition:opacity .15s}
.cap small{display:block;font-size:13px;font-weight:500;color:var(--muted);letter-spacing:0}
.step-tag{font-size:12px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--violet)}
.desk{position:relative;width:100%;max-width:760px;flex:1 1 0;min-height:0}

/* ---------- fake app window ---------- */
.win{position:absolute;left:50%;top:50%;transform-origin:center;width:760px;height:430px;margin:-215px 0 0 -380px;background:var(--surface);border:1px solid var(--hair);border-radius:12px;box-shadow:0 12px 40px rgba(24,22,31,.10);overflow:hidden;display:flex;flex-direction:column}
.wbar{display:flex;align-items:center;gap:4px;padding:8px 10px;border-bottom:1px solid var(--hair);background:var(--paper);flex:none}
.wbar b{font-size:12px;letter-spacing:.05em;margin-right:6px}
.tab{font-size:12px;font-weight:500;color:var(--muted);padding:5px 9px;border-radius:4px;border:1px solid transparent;white-space:nowrap}
.tab.on{color:var(--ink);background:var(--surface);border-color:var(--hair);font-weight:600}
.pill{margin-left:auto;font-size:12px;font-weight:600;background:var(--soft);color:var(--violet);border-radius:999px;padding:4px 10px;white-space:nowrap}
.wbody{position:relative;flex:1;min-height:0;overflow:hidden}
.pane{position:absolute;inset:0;padding:12px;display:flex;flex-direction:column;gap:8px;opacity:0;pointer-events:none}
.pane.vis{pointer-events:auto}
.back{font-size:12px;color:var(--muted)}
.mini{font-size:11px;font-weight:700;letter-spacing:.05em;text-transform:uppercase;color:var(--muted)}
.card{background:var(--surface);border:1px solid var(--hair);border-radius:10px;padding:8px 10px;font-size:12px;position:relative}
.card b{display:block;font-size:12.5px}
.card span{color:var(--muted);font-size:11px;line-height:1.3;display:block}
.card.hot{border-color:var(--violet);box-shadow:0 0 0 2px var(--soft)}
.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:8px}
.grid.g2{grid-template-columns:repeat(2,1fr)}
.drop{flex:1;border:2px dashed var(--hair);border-radius:12px;display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;gap:4px;padding:8px;position:relative;min-height:0;overflow:hidden}
.drop.hot{border-color:var(--violet);background:var(--soft)}
.drop b{font-size:14px}.drop span{font-size:11.5px;color:var(--muted)}
.drop .ic{font-size:22px}
.run{width:100%;border:0;border-radius:10px;padding:13px;font:700 17px Archivo,sans-serif;letter-spacing:.02em;background:var(--sunken);color:var(--muted);flex:none;transition:none}
.run.armed{background:var(--violet);color:#fff}
.run.press{transform:scale(.985)}
.hint{font-size:11.5px;color:var(--muted);text-align:center;flex:none}
.bar{height:8px;border-radius:99px;background:var(--sunken);overflow:hidden;flex:none}
.bar i{display:block;height:100%;width:0;background:var(--violet)}
.ba{position:relative;flex:1;min-height:0;border-radius:10px;overflow:hidden;background:#000}
.ba img,.ba video{position:absolute;inset:0;width:100%;height:100%;object-fit:cover}
.ba .after{clip-path:inset(0 0 0 50%)}
.ba .handle{position:absolute;top:0;bottom:0;width:3px;background:#fff;box-shadow:0 0 6px rgba(0,0,0,.4);left:50%;touch-action:none;cursor:ew-resize}
.ba .handle::after{content:"↔";position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);width:30px;height:30px;border-radius:50%;background:#fff;color:#111;display:grid;place-items:center;font-size:14px}
.tag{position:absolute;top:8px;font-size:10px;font-weight:700;letter-spacing:.05em;color:#fff;background:#0009;padding:3px 7px;border-radius:4px}
.tag.l{left:8px}.tag.r{right:8px;background:var(--violet)}
.field{display:flex;flex-direction:column;gap:2px;font-size:11px;color:var(--muted)}
.field div{border:1px solid var(--hair);border-radius:6px;padding:6px 8px;color:var(--ink);font-size:12.5px;min-height:29px;background:var(--surface);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.seg{display:flex;gap:4px;flex-wrap:wrap}
.seg i{font-style:normal;border:1px solid var(--hair);border-radius:6px;padding:4px 8px;font-size:11.5px;background:var(--surface)}
.seg i.on{border-color:var(--violet);background:var(--soft);color:var(--violet);font-weight:600}
.ok-dot{display:inline-grid;place-items:center;width:16px;height:16px;border-radius:50%;background:var(--violet);color:#fff;font-size:10px;margin-right:6px}
.tray{flex:none;border:1px dashed var(--hair);border-radius:8px;padding:6px 10px;font-size:11.5px;color:var(--muted);background:var(--paper);display:flex;gap:8px;align-items:center}
.file{background:var(--surface);border:1px solid var(--hair);border-radius:6px;padding:3px 8px;color:var(--ink);font-weight:600}
.btns{display:flex;gap:6px;flex-wrap:wrap;flex:none}
.b{border:1px solid var(--hair);background:var(--surface);color:var(--ink);border-radius:8px;padding:9px 12px;font:600 12.5px Archivo,sans-serif;position:relative}
.b.pri{background:var(--violet);color:#fff;border-color:var(--violet)}
.b.lit{outline:3px solid var(--violet);outline-offset:2px}
.spin{width:44px;height:44px;border-radius:50%;border:4px solid var(--sunken);border-top-color:var(--violet)}

/* ---------- cursor + turn ring ---------- */
.cursor{position:absolute;left:0;top:0;z-index:20;width:26px;height:26px;pointer-events:none;will-change:transform;opacity:0}
.cursor svg{filter:drop-shadow(0 2px 3px rgba(0,0,0,.35))}
.cursor::before{content:"";position:absolute;left:-9px;top:-9px;width:24px;height:24px;border-radius:50%;background:var(--violet);opacity:0;transform:scale(.4)}
.cursor.down::before{opacity:.35;transform:scale(1);transition:.15s}
.cursor.down svg{transform:scale(.85)}
.ring{position:absolute;z-index:19;border:3px solid var(--violet);border-radius:12px;pointer-events:none;opacity:0;animation:pulse 1.2s ease-in-out infinite;display:none}
.ring.on{opacity:1;display:block}
.ring.on{pointer-events:auto;cursor:pointer;background:transparent}
.ring em{position:absolute;left:50%;top:100%;transform:translateX(-50%);margin-top:8px;white-space:nowrap;font-style:normal;font-size:12px;font-weight:700;background:var(--violet);color:#fff;padding:4px 10px;border-radius:99px}
.ring em::before{content:"";position:absolute;left:50%;top:-5px;width:9px;height:9px;background:inherit;transform:translateX(-50%) rotate(45deg)}
@keyframes pulse{50%{box-shadow:0 0 0 8px color-mix(in srgb,var(--violet) 25%,transparent)}}
.next{position:absolute;right:12px;top:12px;z-index:21;background:var(--ok);color:#fff;border-radius:99px;padding:4px 10px;font-size:12px;font-weight:700;opacity:0;transition:opacity .2s;pointer-events:none}
.next.on{opacity:1}

/* ---------- reduced motion: a readable static walkthrough ---------- */
.reduce .stage{position:relative;top:0;height:auto;padding:24px 16px}
.reduce .desk{flex:none;height:520px}
.reduce .cursor,.reduce .ring{display:none!important}
.reduce .cap{opacity:1}
.reduce .hero .down b{animation:none}
@media(prefers-reduced-motion:reduce){.ring,.hero .down b{animation:none}}

/* narrow layout: the app window is drawn 380px wide and scaled to fit (how.js fit()) */
.win.narrow .tab:not(.on){display:none}
.win.narrow .grid:not(.g2){grid-template-columns:repeat(2,1fr)}
.win.narrow .split{flex-direction:column;gap:8px;padding:8px}
.win.narrow .split .form{gap:5px}
.win.narrow .split .form>.seg:first-child{display:none}
.win.narrow .split .field div{padding:3px 8px;min-height:22px}
.win.narrow .rbox{width:100%;height:34%;min-height:120px;flex:none}
@media(max-width:520px){.brand{font-size:12px;letter-spacing:0}.top .wrap{gap:6px}.top nav{flex-wrap:nowrap;gap:0}.top nav a{padding:9px 7px;font-size:12px;white-space:nowrap}}
/* tap area for the chapter dots */
.rail a::before{content:"";position:absolute;inset:-9px}
/* phones on their side: window left, caption right, no rail, slimmer header */
@media(max-height:520px) and (orientation:landscape){
  .top .wrap{height:40px}.rail{display:none}.sticky-cta{padding:4px 12px}.sticky-cta .cta{padding:7px 16px}.sticky-cta a.s{padding:8px}
  .stage{top:40px;height:calc(100svh - 40px);flex-direction:row;flex-wrap:wrap;align-content:center;padding:0 12px 60px;gap:4px 12px}
  .step-tag{flex:0 0 100%;text-align:center;font-size:11px}
  .desk{flex:1 1 60%;height:calc(100svh - 40px - 60px - 22px)}
  .cap{flex:0 0 30%;font-size:18px;text-align:left}
  .stage .note{display:none}
}
.win.narrow #v1g .card span{display:none}
.ring em[data-flip]::before{top:auto;bottom:-5px}

/* blinking scroll cue */
.scrollhint{position:fixed;z-index:45;right:24px;top:50%;transform:translateY(-50%);width:96px;display:flex;flex-direction:column;align-items:center;gap:2px;text-align:center;font:700 12px/1.3 Archivo,sans-serif;letter-spacing:.06em;color:var(--violet);pointer-events:none;animation:hintblink 1.4s ease-in-out infinite;transition:opacity .4s}
.scrollhint span{margin-bottom:6px}
.scrollhint i{width:22px;height:22px;border:solid var(--violet);border-width:0 4px 4px 0;transform:rotate(45deg) scale(.6);margin-top:-8px;animation:hintdrop 1.4s ease-in-out infinite}
.scrollhint i:nth-of-type(2){animation-delay:.15s}.scrollhint i:nth-of-type(3){animation-delay:.3s}
.scrollhint.off{opacity:0!important;animation:none}
@keyframes hintblink{0%,100%{opacity:1}50%{opacity:.25}}
@keyframes hintdrop{0%,100%{transform:rotate(45deg) scale(.6) translate(0,0)}50%{transform:rotate(45deg) scale(.6) translate(5px,5px)}}
@media(max-width:899px){.scrollhint{right:auto;left:50%;top:auto;bottom:22px;transform:translateX(-50%);width:230px}}
@media(prefers-reduced-motion:reduce){.scrollhint,.scrollhint i{animation:none}}
.scrollhint{background:var(--surface);border:2px solid var(--violet);border-radius:14px;padding:12px 10px 14px;box-shadow:0 8px 28px rgba(0,0,0,.35)}

.top .lang{margin-left:8px;font:600 12px Archivo,sans-serif;color:var(--ink);background:var(--surface);border:1px solid var(--hair);border-radius:6px;padding:8px 6px;min-height:36px}
#v1g .card{padding:6px 9px}#v1g .card span{line-height:1.2}
/* phone header: brand + three tutorial links + language select must fit in every language */
@media(max-width:520px){.top .wrap{padding:0 8px;gap:4px;min-width:0}.brand{font-size:11px;padding:14px 2px}.top nav{min-width:0}.top nav a{padding:9px 4px;font-size:11.5px}.top .lang{margin-left:2px;padding:8px 2px;min-width:0;width:46px}}
@media(max-width:359px){.brand span{display:none}}

/* progress: label (phones), passed dots, done state */
.rlabel{display:none;font:600 11px/1 Archivo,sans-serif;color:var(--muted);margin-right:6px;white-space:nowrap}
.rlabel.done{color:var(--ok);font-weight:700}
.rail a.seen{background:var(--violet);opacity:.5}.rail a.on{opacity:1}
@media(max-width:899px){.rail{align-items:center}.rlabel{display:inline}}
/* the next tutorial, once this one is finished */
.top nav a.nextup{position:relative;color:var(--ink);outline:2px solid var(--violet);outline-offset:1px;animation:hintblink 1.1s ease-in-out infinite}
.top nav a.nextup::after{content:attr(data-tip);position:absolute;top:100%;left:50%;transform:translateX(-50%);margin-top:8px;white-space:nowrap;background:var(--violet);color:#fff;font:700 11px/1 Archivo,sans-serif;padding:5px 9px;border-radius:99px}
.top nav a.nextup:last-child::after{left:auto;right:0;transform:none}
.sticky-cta .cta.blink{animation:hintblink 1.1s ease-in-out infinite}
@media(prefers-reduced-motion:reduce){.top nav a.nextup,.sticky-cta .cta.blink{animation:none}}

/* mid-page "keep scrolling" on phones sits on the right edge, clear of the caption and the Try-it button */
@media(max-width:899px){.scrollhint.side{left:auto;right:6px;bottom:auto;top:50%;transform:translateY(-50%);width:78px;font-size:10px;padding:8px 6px}}

/* logo mark: the same white file the app uses — tinted violet on light, left white on dark (as brand.css / courses.html do) */
.brand{display:inline-flex;align-items:center;gap:8px}
.brand .mark{width:34px;height:34px;object-fit:contain;flex:none;filter:brightness(0) saturate(100%) invert(47%) sepia(96%) saturate(374%) hue-rotate(222deg) brightness(58%) contrast(179%)}
@media(prefers-color-scheme:dark){.brand .mark{filter:none}}
@media(max-width:520px){.brand .mark{width:28px;height:28px}.brand{gap:5px}}
@media(max-width:520px){.top nav a{min-width:40px;text-align:center}}
/* four tutorials in the header (2026-10-01): on a phone the logo mark stands for the name */
@media(max-width:760px){.brand span{display:none}}
@media(max-width:899px){.top nav{flex-wrap:nowrap}}
/* phones and tablets: the tutorial links stay one line each and scroll sideways in one row (they overlapped at 375 px and
   wrapped to two lines at 768); how.js scrolls the open one into view */
@media(max-width:899px){.top nav{overflow-x:auto;scrollbar-width:none;flex:1 1 auto;min-width:0;justify-content:flex-start}.top nav::-webkit-scrollbar{display:none}.top nav a{flex:none;min-width:0;white-space:nowrap}.top .lang{flex:none}}
@media(min-width:521px) and (max-width:899px){.top nav a{font-size:12px;padding:6px 7px}}
@media(max-width:820px){.top .brand span{display:none}} /* the logo stays; the five links need the room (was 760) */