/* ============================================================
   site-nav.css — the site header and the menu, on every page.
   Markup comes from worker/site-nav.ts (static pages get it written in by
   `npm run nav:sync`); behaviour from /assets/app.js. Self-contained: pages
   that don't load notebook.css (Solomon, Success Stories) look the same.
   ============================================================ */
.topbar,.menu{
  --nv-bg:#000;--nv-panel:#070707;--nv-ink:#f6f4ef;--nv-body:#d4d2cc;--nv-muted:#a9a7a0;--nv-dim:#8a8883;
  --nv-line:rgba(242,240,234,.14);--nv-line-soft:rgba(242,240,234,.07);--nv-ease:cubic-bezier(.16,1,.3,1);
}

/* ---- header ---- */
.topbar{position:sticky;top:0;z-index:1000;display:grid;grid-template-columns:1fr auto 1fr;align-items:center;gap:16px;
  padding:16px clamp(22px,5vw,64px);border:0;background:linear-gradient(180deg,rgba(0,0,0,.92),rgba(0,0,0,.5) 70%,transparent);
  backdrop-filter:blur(5px);-webkit-backdrop-filter:blur(5px);transition:padding .3s var(--nv-ease),background-color .3s var(--nv-ease);}
.topbar.overlay{position:fixed;left:0;right:0;}
.topbar.scrolled{padding-top:8px;padding-bottom:8px;background:rgba(0,0,0,.86);}
html:has(.menu.open) .topbar{padding-top:16px;padding-bottom:16px;background:var(--nv-panel);backdrop-filter:none;-webkit-backdrop-filter:none;}

.topbar .menu-btn{justify-self:start;background:transparent;border:1px solid var(--nv-line);border-radius:2px;padding:9px 10px;margin:0;
  cursor:pointer;display:inline-flex;flex-direction:column;justify-content:center;align-items:center;gap:4px;}
.topbar .menu-btn span{width:18px;height:1.4px;background:var(--nv-ink);display:block;transition:transform .3s var(--nv-ease),opacity .2s;}
.topbar .menu-btn[aria-expanded="true"] span:nth-child(1){transform:translateY(5.4px) rotate(45deg);}
.topbar .menu-btn[aria-expanded="true"] span:nth-child(2){opacity:0;}
.topbar .menu-btn[aria-expanded="true"] span:nth-child(3){transform:translateY(-5.4px) rotate(-45deg);}
.topbar .menu-btn:focus-visible,.topbar .lang-btn:focus-visible{outline:2px solid var(--nv-ink);outline-offset:2px;}

.topbar .brand{font-family:"Bodoni Moda",serif;font-weight:700;font-size:22px;letter-spacing:.1em;color:var(--nv-ink);text-decoration:none;
  justify-self:center;display:inline-flex;align-items:center;gap:0;white-space:nowrap;text-transform:none;}
.topbar .brand span{color:var(--nv-ink);}
.topbar .brand .ruby{flex:none;width:16px;height:16px;margin:0 13px;display:inline-flex;align-items:center;justify-content:center;opacity:.95;}
.topbar .brand .ruby canvas{width:16px;height:16px;display:block;}

.topbar .topbar-right{display:flex;align-items:center;gap:14px;justify-self:end;}
.topbar .topbar-logo-link{flex:none;}
.topbar .topbar-logo{height:32px;width:auto;max-width:none;opacity:.92;filter:grayscale(1) brightness(1.4) contrast(1.1);}

/* language picker: app.js toggles .open / .show on .lang */
.topbar .lang{position:relative;}
.topbar .lang-btn{display:inline-flex;align-items:center;gap:7px;background:transparent;border:1px solid var(--nv-line);border-radius:2px;
  padding:8px 10px;color:var(--nv-muted);font-family:"IBM Plex Mono",monospace;font-size:11px;letter-spacing:.1em;text-transform:none;cursor:pointer;}
.topbar .lang-btn:hover,.topbar .lang-btn[aria-expanded="true"]{color:var(--nv-ink);border-color:rgba(242,240,234,.32);}
.topbar .lang-btn svg{width:15px;height:15px;flex:none;max-width:none;opacity:1;}
.topbar .lang-btn .chev{width:12px;height:12px;transition:transform .25s;}
.topbar .lang-btn[aria-expanded="true"] .chev{transform:rotate(180deg);}
.topbar .lang-menu{position:absolute;right:0;top:calc(100% + 8px);z-index:30;min-width:200px;max-height:60vh;overflow-y:auto;
  background:var(--nv-panel);border:1px solid var(--nv-line);border-radius:4px;padding:6px;box-shadow:0 24px 60px rgba(0,0,0,.6);
  display:none;opacity:0;transform:translateY(-6px);transition:opacity .2s var(--nv-ease),transform .2s var(--nv-ease);}
.topbar .lang.open .lang-menu{display:block;}
.topbar .lang.open.show .lang-menu{opacity:1;transform:none;}
.topbar .lang-opt{display:flex;align-items:center;gap:10px;width:100%;background:transparent;border:0;border-radius:3px;padding:9px 11px;
  color:var(--nv-body);font-family:"Spectral",Georgia,serif;font-size:13.5px;text-align:left;cursor:pointer;}
.topbar .lang-opt .en{margin-left:auto;font-family:"IBM Plex Mono",monospace;font-size:10px;letter-spacing:.1em;color:var(--nv-dim);}
.topbar .lang-opt:hover{background:rgba(242,240,234,.06);color:var(--nv-ink);}
.topbar .lang-opt[aria-selected="true"]{color:var(--nv-ink);}

/* phones: the 1fr|auto|1fr row must fit, so the controls get compact */
@media(max-width:760px){
  .topbar .topbar-logo-link{display:inline-flex;align-items:center;justify-content:center;min-width:44px;min-height:44px;}
  .topbar .menu-btn,.topbar .lang-btn{min-width:44px;min-height:44px;padding:12px;justify-content:center;}
  .topbar .brand{min-height:44px;}
}
@media(max-width:520px){
  .topbar{gap:10px;}
  .topbar .brand{font-size:clamp(14px,calc(12vw - 25px),22px);}
  .topbar .brand .ruby{margin:0 .4em;width:13px;height:13px;}.topbar .brand .ruby canvas{width:13px;height:13px;}
  .topbar .topbar-right{gap:8px;}
  .topbar .lang-btn{padding:8px;}
  .topbar .lang-btn .lang-cur,.topbar .lang-btn .chev{display:none;}
  .topbar .topbar-logo{height:28px;}
}

/* ---- menu: a panel under the header, in columns ---- */
.menu{position:fixed;inset:0;z-index:999;display:block;margin:0;
  padding:calc(70px + env(safe-area-inset-top)) clamp(12px,3vw,40px) 40px;
  background:rgba(0,0,0,.66);backdrop-filter:blur(6px);-webkit-backdrop-filter:blur(6px);
  overflow-y:auto;overscroll-behavior:contain;-webkit-overflow-scrolling:touch;
  opacity:0;visibility:hidden;pointer-events:none;transition:opacity .28s var(--nv-ease),visibility 0s linear .28s;}
.menu.open{opacity:1;visibility:visible;pointer-events:auto;transition:opacity .28s var(--nv-ease);}
.menu::before,.menu::after{content:none;display:none;}
html:has(.menu.open){overflow:hidden;}

.menu .mega-panel{max-width:1240px;margin:0 auto;display:grid;grid-template-columns:repeat(3,minmax(0,1fr)) minmax(250px,.95fr);
  background:var(--nv-panel);border:1px solid var(--nv-line);border-radius:0 0 10px 10px;box-shadow:0 40px 90px rgba(0,0,0,.7);
  transform:translateY(-8px);transition:transform .45s var(--nv-ease);}
.menu.open .mega-panel{transform:none;}
.menu .mega-cols{display:contents;}
.menu .mega-col{padding:26px 18px 28px;border-right:1px solid var(--nv-line-soft);min-width:0;}
.menu .mega-h{margin:0 0 12px 10px;font-family:"IBM Plex Mono",monospace;font-weight:500;font-size:10px;letter-spacing:.3em;text-transform:uppercase;color:var(--nv-dim);}

.menu .mega-item{position:relative;display:flex;align-items:flex-start;gap:13px;min-height:0;padding:9px 10px;border-radius:6px;
  color:var(--nv-ink);text-decoration:none;font:inherit;letter-spacing:normal;transition:background .2s;}
.menu .mega-item::before,.menu .mega-item::after{content:none;}
.menu .mega-item:hover,.menu .mega-item:focus-visible{background:rgba(242,240,234,.05);outline:none;}
.menu .mega-item:focus-visible{box-shadow:inset 0 0 0 1px rgba(242,240,234,.4);}
.menu .mi-ic{flex:none;width:34px;height:34px;display:grid;place-items:center;border:1px solid var(--nv-line);border-radius:6px;
  color:var(--nv-body);background:rgba(242,240,234,.02);transition:color .2s,border-color .2s;}
.menu .mi-ic svg{width:18px;height:18px;max-width:none;display:block;}
.menu .mega-item:hover .mi-ic,.menu .mega-item[aria-current="page"] .mi-ic{color:var(--nv-ink);border-color:rgba(242,240,234,.38);}
.menu .mi-tx{display:flex;flex-direction:column;gap:2px;min-width:0;padding-top:1px;}
.menu .mi-tx b{font-family:"Bodoni Moda",serif;font-weight:600;font-style:normal;font-size:15px;line-height:1.25;letter-spacing:.01em;color:var(--nv-ink);}
.menu .mi-tx small{font-family:"Spectral",Georgia,serif;font-size:13px;line-height:1.4;color:var(--nv-muted);}
.menu .mega-item[aria-current="page"]{background:rgba(242,240,234,.06);}
.menu .mega-item[aria-current="page"] .mi-tx b::after{content:"";display:inline-block;width:5px;height:5px;margin-left:8px;border-radius:50%;background:var(--nv-ink);vertical-align:middle;}
/* a child sits under its parent, joined by a bracket from the parent's icon */
.menu .mega-item.child{margin-left:36px;}
.menu .mega-item.child::before{content:"";position:absolute;left:-9px;top:-10px;width:18px;height:37px;
  border-left:1px solid var(--nv-line);border-bottom:1px solid var(--nv-line);border-bottom-left-radius:7px;}

.menu .mega-aside{padding:26px 22px 28px;min-width:0;background:linear-gradient(180deg,rgba(242,240,234,.03),transparent 60%);border-radius:0 0 10px 0;}
.menu .mega-feature{display:block;margin:0 0 24px;border:1px solid var(--nv-line);border-radius:8px;overflow:hidden;background:#000;
  color:var(--nv-ink);text-decoration:none;transition:border-color .2s;}
.menu .mega-feature::before,.menu .mega-feature::after{content:none;}
.menu .mega-feature:hover,.menu .mega-feature:focus-visible{border-color:rgba(242,240,234,.4);outline:none;}
.menu .mega-feature img{display:block;width:100%;height:auto;aspect-ratio:16/9;object-fit:cover;}
.menu .mega-feature .mf-k{display:block;padding:12px 14px 0;font-family:"IBM Plex Mono",monospace;font-size:9.5px;letter-spacing:.24em;text-transform:uppercase;color:var(--nv-dim);}
.menu .mega-feature b{display:block;padding:4px 14px 0;font-family:"Bodoni Moda",serif;font-weight:700;font-size:17px;letter-spacing:.08em;}
.menu .mega-feature small{display:block;padding:3px 14px 14px;font-family:"Spectral",Georgia,serif;font-size:13px;color:var(--nv-muted);}
.menu .mega-quicks{display:flex;flex-direction:column;}
.menu .mega-quick{display:flex;align-items:center;justify-content:space-between;gap:10px;min-height:40px;padding:8px 10px;
  border-bottom:1px solid var(--nv-line-soft);color:var(--nv-body);text-decoration:none;font-family:"IBM Plex Mono",monospace;font-size:12px;letter-spacing:.06em;
  transition:color .2s,padding .3s var(--nv-ease);}
.menu .mega-quick::before,.menu .mega-quick::after{content:none;}
.menu .mega-quick span{color:var(--nv-dim);transition:transform .3s var(--nv-ease),color .2s;}
.menu .mega-quick:hover,.menu .mega-quick:focus-visible,.menu .mega-quick[aria-current="page"]{color:var(--nv-ink);outline:none;}
.menu .mega-quick:hover span{transform:translateX(3px);color:var(--nv-ink);}

/* narrower desktops: three columns, the aside becomes a row underneath */
@media(max-width:1120px){
  .menu .mega-panel{grid-template-columns:repeat(3,minmax(0,1fr));}
  .menu .mega-col:nth-child(3){border-right:0;}
  .menu .mega-aside{grid-column:1/-1;display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:0 28px;align-items:start;
    border-top:1px solid var(--nv-line-soft);border-radius:0 0 10px 10px;}
  .menu .mega-feature{grid-row:1/3;margin:0;display:grid;grid-template-columns:42% 1fr;align-items:center;}
  .menu .mega-feature img{grid-row:1/4;height:100%;}
  .menu .mega-feature .mf-k{padding-top:0;}
  .menu .mega-feature small{padding-bottom:0;}
}
/* tablets and phones: a full-height sheet */
@media(max-width:860px){
  .menu{padding:calc(76px + env(safe-area-inset-top)) 0 0;background:var(--nv-panel);backdrop-filter:none;-webkit-backdrop-filter:none;}
  .menu .mega-panel{grid-template-columns:minmax(0,1fr) minmax(0,1fr);border:0;border-top:1px solid var(--nv-line-soft);border-radius:0;box-shadow:none;
    padding-bottom:calc(24px + env(safe-area-inset-bottom));}
  .menu .mega-col{border-right:0;border-bottom:1px solid var(--nv-line-soft);padding:20px 12px 18px;}
  .menu .mega-col:nth-child(odd){border-right:1px solid var(--nv-line-soft);}
  .menu .mega-col:nth-child(3){grid-column:1/-1;border-right:0;display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);column-gap:8px;}
  .menu .mega-col:nth-child(3) .mega-h{grid-column:1/-1;}
  .menu .mega-aside{background:none;border-top:0;padding:20px 12px 8px;}
}
@media(max-width:600px){
  .menu .mega-panel{grid-template-columns:minmax(0,1fr);}
  .menu .mega-col,.menu .mega-col:nth-child(odd){border-right:0;padding:18px 8px 14px;}
  .menu .mega-col:nth-child(3){display:block;}
  .menu .mega-item{padding:8px;gap:12px;}
  .menu .mi-ic{width:32px;height:32px;}
  .menu .mi-tx b{font-size:15px;}
  .menu .mi-tx small{font-size:12.5px;}
  .menu .mega-aside{display:block;padding:18px 8px 6px;}
  .menu .mega-feature{display:grid;grid-template-columns:40% 1fr;margin-bottom:18px;}
  .menu .mega-quick{min-height:44px;}
}
@media(prefers-reduced-motion:reduce){
  .menu,.menu.open,.menu .mega-panel,.topbar .menu-btn span{transition:none;}
  .menu .mega-panel{transform:none;}
}