/* Probandum — modern, clean, semantic color. Hand-written, zero frameworks. */

/* ---------- fonts (self-hosted, subset) ---------- */
@font-face{font-family:'IBM Plex Serif';font-style:normal;font-weight:600;font-display:swap;
  src:url('fonts/IBMPlexSerif-SemiBold.woff2') format('woff2')}
@font-face{font-family:'IBM Plex Serif';font-style:italic;font-weight:400;font-display:swap;
  src:url('fonts/IBMPlexSerif-Italic.woff2') format('woff2')}
@font-face{font-family:'IBM Plex Sans';font-style:normal;font-weight:400;font-display:swap;
  src:url('fonts/IBMPlexSans-Regular.woff2') format('woff2')}
@font-face{font-family:'IBM Plex Sans';font-style:normal;font-weight:500;font-display:swap;
  src:url('fonts/IBMPlexSans-Medium.woff2') format('woff2')}
@font-face{font-family:'IBM Plex Mono';font-style:normal;font-weight:400;font-display:swap;
  src:url('fonts/IBMPlexMono-Regular.woff2') format('woff2')}
@font-face{font-family:'IBM Plex Mono';font-style:normal;font-weight:500;font-display:swap;
  src:url('fonts/IBMPlexMono-Medium.woff2') format('woff2')}

/* ---------- tokens ---------- */
:root{
  color-scheme:light;
  --bg:#FFFFFF; --bg-soft:#F6F7FB; --card:#FFFFFF;
  --ink:#0F1216; --ink-2:#3A3F47; --muted:#6B7280;
  --hair:#E5E7EB; --hair-2:#D8DBE0;
  --acc-1:#1E3A8A; --acc-2:#7C3AED;                    /* dark-blue → purple */
  --accent:#2547C9;                                     /* flat interactive blue */
  --acc-ink:#1E3A8A;                                    /* accent text on light */
  --acc-bg:#EDF0FE; --acc-bg-2:#F3EEFE;
  --grad:linear-gradient(100deg,var(--acc-1),var(--acc-2));
  --grad-soft:linear-gradient(100deg,var(--acc-bg),var(--acc-bg-2));
  --amber:#B45309; --amber-ink:#92400E; --amber-bg:#FEF6E7;
  --teal:#0E7490; --teal-ink:#155E75; --teal-bg:#ECFEFF;
  --neut:#6B7280; --neut-bg:#F3F4F6;
  --shadow:0 1px 2px rgba(15,18,22,.05),0 8px 24px -12px rgba(15,18,22,.10);
  --shadow-lg:0 2px 4px rgba(15,18,22,.04),0 20px 44px -20px rgba(15,18,22,.16);
  --glow-a:color-mix(in srgb,var(--acc-2) 9%, transparent);
  --glow-b:color-mix(in srgb,var(--acc-1) 8%, transparent);
  --serif:'IBM Plex Serif',Georgia,serif;
  --sans:'IBM Plex Sans',system-ui,sans-serif;
  --mono:'IBM Plex Mono',ui-monospace,SFMono-Regular,Menlo,monospace;
  --maxw:1200px;
}
[data-theme="dark"]{
  color-scheme:dark;
  --bg:#0B0D12; --bg-soft:#0E1118; --card:#12151D;
  --ink:#E8EAEF; --ink-2:#C2C8D4; --muted:#8B93A5;
  --hair:#222836; --hair-2:#2C3446;
  --accent:#8AA0FF; --acc-ink:#A7B8FF;
  --acc-bg:#1A2138; --acc-bg-2:#241B3E;
  --amber:#D9A05B; --amber-ink:#E4B87E; --amber-bg:#2A2114;
  --teal:#22D3EE; --teal-ink:#67E8F9; --teal-bg:#123A44;
  --neut:#8B93A5; --neut-bg:#1B2029;
  --shadow:0 1px 2px rgba(0,0,0,.4),0 8px 24px -12px rgba(0,0,0,.5);
  --shadow-lg:0 2px 4px rgba(0,0,0,.4),0 20px 44px -20px rgba(0,0,0,.6);
  --glow-a:color-mix(in srgb,var(--acc-2) 20%, transparent);
  --glow-b:color-mix(in srgb,var(--acc-1) 24%, transparent);
}

/* ---------- base ---------- */
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
body{
  margin:0; background:var(--bg); color:var(--ink);
  font-family:var(--sans); font-size:17.5px; line-height:1.6;
  -webkit-font-smoothing:antialiased; text-rendering:optimizeLegibility;
  transition:background .25s ease, color .25s ease;
}
::selection{background:var(--acc-bg); color:var(--acc-ink)}
h1,h2,h3{font-family:var(--serif); font-weight:600; line-height:1.14; margin:0 0 .5em; letter-spacing:-.015em}
h2{font-size:clamp(28px,3.2vw,40px)}
p{margin:0 0 1em}
a{color:var(--acc-ink); text-underline-offset:3px; text-decoration-color:color-mix(in srgb, var(--accent) 40%, transparent)}
a:hover{text-decoration-color:var(--accent)}
img{max-width:100%; height:auto; display:block}
.wrap{max-width:var(--maxw); margin:0 auto; padding:0 clamp(20px,4vw,40px)}
section{padding:clamp(64px,8vw,110px) 0; position:relative}
.band{background:var(--bg-soft); border-top:1px solid var(--hair); border-bottom:1px solid var(--hair)}
.overline{
  font-family:var(--mono); font-size:13px; letter-spacing:.18em; text-transform:uppercase;
  color:var(--muted); margin:0 0 16px;
}
.overline .tick{color:var(--accent)}
.lede{font-size:19px; color:var(--ink-2); max-width:58ch}
.muted{color:var(--muted)}
.small{font-size:14px}

/* mono chip — the machine voice */
.chip{
  display:inline-block; font-family:var(--mono); font-size:11.5px; line-height:1;
  padding:.45em .7em; border-radius:999px; border:1px solid color-mix(in srgb,currentColor 35%,transparent);
  background:var(--neut-bg); color:var(--neut); white-space:nowrap; vertical-align:baseline;
}
.chip.acc{background:var(--grad-soft); color:var(--acc-ink)}
.chip.amber{background:var(--amber-bg); color:var(--amber-ink)}
.chip.teal{background:var(--teal-bg); color:var(--teal-ink)}

/* ---------- header ---------- */
header.site{
  position:sticky; top:0; z-index:50;
  background:color-mix(in srgb,var(--bg) 82%, transparent);
  backdrop-filter:blur(12px); -webkit-backdrop-filter:blur(12px);
  border-bottom:1px solid var(--hair);
}
header.site .wrap{display:flex; align-items:center; gap:24px; height:68px}
.wordmark{
  font-family:var(--serif); font-weight:600; font-size:23px; color:var(--ink);
  text-decoration:none; letter-spacing:-.02em; display:flex; align-items:baseline; gap:7px;
}
.wordmark .halmos{position:relative; top:1px; flex:none}
nav.site{margin-left:auto; display:flex; align-items:center; gap:24px}
nav.site a.navlink{font-family:var(--mono); font-size:12.5px; letter-spacing:.08em; color:var(--ink-2); text-decoration:none; text-transform:uppercase}
nav.site a.navlink:hover{color:var(--acc-ink)}

/* ---------- theme toggle (single button, sun/moon) ---------- */
.theme-toggle{
  appearance:none; -webkit-appearance:none; cursor:pointer;
  width:32px; height:32px; border-radius:50%; padding:0;
  display:grid; place-items:center; position:relative;
  border:1.6px solid var(--hair-2); background:transparent; color:var(--ink-2);
  transition:border-color .15s ease, color .15s ease;
}
.theme-toggle:hover{border-color:var(--accent); color:var(--acc-ink)}
.theme-toggle:focus-visible{outline:2px solid var(--accent); outline-offset:2px}
.theme-toggle svg{grid-area:1/1; transition:opacity .2s ease, transform .25s ease}
.theme-toggle .tt-moon{opacity:0; transform:rotate(-40deg) scale(.6)}
[data-theme="dark"] .theme-toggle .tt-moon{opacity:1; transform:none}
[data-theme="dark"] .theme-toggle .tt-sun{opacity:0; transform:rotate(40deg) scale(.6)}

/* ---------- buttons & forms ---------- */
.btn{
  display:inline-block; font-family:var(--sans); font-weight:500; font-size:15.5px;
  background:var(--grad); color:#FFFFFF; text-decoration:none; border:0;
  padding:13px 26px; border-radius:10px; cursor:pointer;
  box-shadow:0 1px 2px rgba(30,58,138,.25);
  transition:filter .15s ease, transform .15s ease, box-shadow .15s ease;
}
.btn:hover{filter:brightness(1.08); box-shadow:0 4px 16px -4px rgba(124,58,237,.45)}
.btn:active{transform:translateY(1px)}
form.capture{display:flex; gap:10px; flex-wrap:wrap}
form.capture input[type=email]{
  flex:1 1 260px; font-family:var(--mono); font-size:15px; color:var(--ink);
  background:var(--card); border:1px solid var(--hair-2); border-radius:10px; padding:13px 16px;
}
form.capture input[type=email]:focus{outline:2px solid color-mix(in srgb,var(--accent) 50%,transparent); outline-offset:1px; border-color:var(--accent)}
form.capture input[type=email]::placeholder{color:#9CA3AF}
[data-theme="dark"] form.capture input[type=email]::placeholder{color:#5B6474}
.micro{font-size:14px; color:var(--muted); margin-top:12px; max-width:52ch}

/* ---------- hero ---------- */
.hero{padding:clamp(72px,9vw,120px) 0 clamp(60px,7vw,96px); overflow:hidden}
.hero::before{
  content:""; position:absolute; inset:0; pointer-events:none;
  background:
    radial-gradient(640px 320px at 82% 8%, var(--glow-a), transparent 70%),
    radial-gradient(520px 300px at 8% 92%, var(--glow-b), transparent 70%);
}
.hero .wrap{position:relative}
.hero-grid{display:grid; grid-template-columns:minmax(0,7fr) minmax(0,5fr); gap:clamp(36px,5vw,72px); align-items:center}
.hero h1{font-size:clamp(40px,4.8vw,60px); max-width:15ch}
.hero .sub{font-size:19px; color:var(--ink-2); max-width:52ch; margin:0 0 30px}
.hero .sub em{font-style:normal; border-bottom:2px solid color-mix(in srgb,var(--acc-2) 45%,transparent)}
.hero-diagram{background:var(--card); border:1px solid var(--hair); border-radius:16px; padding:22px 22px 14px; margin:0; box-shadow:var(--shadow-lg)}
.hero-diagram figcaption{font-family:var(--mono); font-size:13px; color:var(--muted); margin-top:8px; letter-spacing:.04em}
.hero-diagram svg rect,.hero-diagram svg path,.hero-diagram svg text{transition:fill .25s ease, stroke .25s ease}

/* hero-diagram typography — adjust everything at once via --hd-scale */
.hero-diagram{--hd-scale:1.3}
.hero-diagram svg text{font-family:var(--sans); fill:var(--ink)}
.hero-diagram svg .hd-mut{fill:var(--muted)}
.hero-diagram svg .hd-quote{font-family:var(--serif); font-style:italic; fill:var(--ink)}
.hero-diagram svg .hd-acc{fill:var(--acc-ink); font-family:var(--mono)}
.hero-diagram svg .hd-am{fill:var(--amber-ink); font-family:var(--mono)}
/* proportional sizes (base px = the diagram's design size, scaled by --hd-scale) */
.hero-diagram svg .hd-fs0{font-family:var(--mono); font-size:calc(9.5px * var(--hd-scale))}
.hero-diagram svg .hd-fs1{font-family:var(--mono); font-size:calc(10px * var(--hd-scale))}
.hero-diagram svg .hd-fs2{font-family:var(--mono); font-size:calc(11.5px * var(--hd-scale))}
.hero-diagram svg .hd-fs3{font-size:calc(13.5px * var(--hd-scale))}
.hero-diagram svg .hd-fs4{font-size:calc(15px * var(--hd-scale))}
/* dark-theme recolor of the diagram (moved from inline overrides) */
[data-theme="dark"] .hero-diagram svg .hd-quote{fill:var(--ink)}
[data-theme="dark"] .hero-diagram svg .hd-acc{fill:#9DB2FF}
[data-theme="dark"] .hero-diagram svg .hd-am{fill:var(--amber-ink)}
[data-theme="dark"] .hero-diagram svg .hd-mut{fill:var(--muted)}

/* ---------- problem ---------- */
.failures{margin:30px 0 0; padding:0; list-style:none; display:grid; max-width:860px}
.failures li{
  display:grid; grid-template-columns:150px 1fr; gap:20px; padding:20px 0;
  border-top:1px solid var(--hair); align-items:baseline;
}
.failures li:last-child{border-bottom:1px solid var(--hair)}
.failures .num{font-family:var(--mono); font-size:12.5px; color:var(--amber-ink); letter-spacing:.05em}
.failures p{margin:0; font-size:18px; max-width:56ch}

/* ---------- how it works ---------- */
.cards{display:grid; grid-template-columns:repeat(3,1fr); gap:22px; margin-top:40px}
.card{
  background:var(--card); border:1px solid var(--hair); border-radius:16px; padding:28px 26px 24px;
  display:flex; flex-direction:column; gap:12px; box-shadow:var(--shadow);
  transition:box-shadow .2s ease, transform .2s ease;
}
.card:hover{box-shadow:var(--shadow-lg); transform:translateY(-2px)}
.card h3{font-size:21px; margin:0}
.card p{margin:0; color:var(--ink-2); font-size:15.5px}
.card .chip{align-self:flex-start; margin-top:auto}

/* ---------- story ---------- */
.story-head{max-width:80%}
.story-body{margin:22px 0 8px}
.story-body::after{content:""; display:block; clear:both}
/* floated portrait: text wraps left + bottom while it stays under 60% of the column */
.portrait{float:right; width:180px; max-width:57%; margin:6px 0 18px 30px}
.portrait img{border:1px solid var(--hair-2); border-radius:10px; filter:grayscale(1)}
.portrait figcaption{font-size:12.5px; color:var(--muted); margin-top:10px; line-height:1.5}
.story-text{max-width:75ch}
.story-text p{font-size:18px}
/* the rest of the story (after the quote) wraps under the portrait */
.story-rest{clear:both}
.story-text blockquote{
  margin:22px 0; padding:2px 0 2px 22px;
  border-left:3px solid transparent;
  border-image:linear-gradient(180deg,var(--acc-1),var(--acc-2)) 1;
  font-family:var(--serif); font-style:italic; font-size:19.5px; line-height:1.5; color:var(--ink-2);
}
.story-text blockquote .att{
  display:block; font-family:var(--mono); font-style:normal; font-size:11.5px;
  color:var(--muted); margin-top:10px; letter-spacing:.05em;
}
.punch{font-weight:500; font-size:19px}

/* the 1913 → now comparison */
.compare{margin:52px 0 8px}
.compare-grid{display:grid; grid-template-columns:1.06fr 1fr; gap:24px; align-items:start}
.panel{display:flex; flex-direction:column; border-radius:16px; overflow:hidden; margin:0; box-shadow:var(--shadow)}
.panel .tab{
  font-family:var(--mono); font-size:11.5px; letter-spacing:.14em; text-transform:uppercase;
  padding:12px 18px; display:flex; justify-content:space-between; gap:12px;
}
.panel.arch{background:#F6F3EC; border:1px solid #E7E0D0}
.panel.arch .tab{color:#8A7A58; border-bottom:1px solid #E7E0D0}
.panel.twin{background:var(--card); border:1px solid var(--hair)}
.panel.twin .tab{color:var(--muted); border-bottom:1px solid var(--hair)}
.arch-frame{position:relative; flex:1}
.arch-frame img{width:100%; height:auto; display:block}
.twin-body{padding:14px 10px 6px; flex:1; overflow-x:auto}
.twin-svg{width:100%; height:auto; display:block}
.twin-svg rect,.twin-svg path,.twin-svg text{transition:fill .25s ease, stroke .25s ease}
.twin-svg text{font-family:var(--sans); fill:var(--ink)}
.twin-svg text.tw-l{font-size:12.5px}
.twin-svg text.tw-m{font-family:var(--mono); font-size:10px}
.twin-svg text.tw-s{font-family:var(--mono); font-size:9px}
.plate-cap{
  font-size:12.5px; color:#8A7A58; line-height:1.55;
  padding:12px 18px 14px; border-top:1px solid #E7E0D0;
}
.twin-cap{font-family:var(--mono); font-size:12.5px; color:var(--muted); padding:10px 18px 14px; border-top:1px solid var(--hair)}
/* hover glows on the archival scan */
.hl{
  position:absolute; width:56px; height:56px; border-radius:50%; transform:translate(-50%,-50%);
  opacity:0; transition:opacity .35s ease; pointer-events:auto; cursor:pointer;
  border:2px solid currentColor;
}
.hl::after{content:""; position:absolute; inset:-2px; border-radius:50%; background:currentColor; opacity:.16}
.hl.acc{color:var(--accent)} .hl.amber{color:var(--amber)} .hl.neut{color:var(--neut)}
.hl:hover{opacity:1}
/* cross-panel recognition, no JS — hovering either side lights the counterpart */
.tw-node{cursor:pointer; transition:filter .2s ease}
#compare:has(.tw-node[data-n="1"]:hover) .hl.n1,#compare:has(.tw-node[data-n="2"]:hover) .hl.n2,
#compare:has(.tw-node[data-n="3"]:hover) .hl.n3,#compare:has(.tw-node[data-n="4"]:hover) .hl.n4,
#compare:has(.tw-node[data-n="5"]:hover) .hl.n5,#compare:has(.tw-node[data-n="6"]:hover) .hl.n6,
#compare:has(.tw-node[data-n="7"]:hover) .hl.n7,#compare:has(.tw-node[data-n="8"]:hover) .hl.n8,
#compare:has(.tw-node[data-n="9"]:hover) .hl.n9,#compare:has(.tw-node[data-n="10"]:hover) .hl.n10,
#compare:has(.tw-node[data-n="11"]:hover) .hl.n11,#compare:has(.tw-node[data-n="12"]:hover) .hl.n12,
#compare:has(.tw-node[data-n="13"]:hover) .hl.n13,#compare:has(.tw-node[data-n="14"]:hover) .hl.n14,
#compare:has(.tw-node[data-n="15"]:hover) .hl.n15,#compare:has(.tw-node[data-n="16"]:hover) .hl.n16,
#compare:has(.tw-node[data-n="17"]:hover) .hl.n17,#compare:has(.tw-node[data-n="18"]:hover) .hl.n18,
#compare:has(.tw-node[data-n="19"]:hover) .hl.n19,#compare:has(.tw-node[data-n="20"]:hover) .hl.n20,
#compare:has(.tw-node[data-n="21"]:hover) .hl.n21,#compare:has(.tw-node[data-n="22"]:hover) .hl.n22,
#compare:has(.tw-node[data-n="23"]:hover) .hl.n23,#compare:has(.tw-node[data-n="24"]:hover) .hl.n24,
#compare:has(.tw-node[data-n="25"]:hover) .hl.n25{opacity:1}
#compare .tw-node:hover{filter:drop-shadow(0 2px 6px rgba(15,18,22,.3))}
[data-theme="dark"] #compare .tw-node:hover{filter:drop-shadow(0 2px 8px rgba(0,0,0,.7))}
#compare:has(.hl.n1:hover) .tw-node[data-n="1"],#compare:has(.hl.n2:hover) .tw-node[data-n="2"],
#compare:has(.hl.n3:hover) .tw-node[data-n="3"],#compare:has(.hl.n4:hover) .tw-node[data-n="4"],
#compare:has(.hl.n5:hover) .tw-node[data-n="5"],#compare:has(.hl.n6:hover) .tw-node[data-n="6"],
#compare:has(.hl.n7:hover) .tw-node[data-n="7"],#compare:has(.hl.n8:hover) .tw-node[data-n="8"],
#compare:has(.hl.n9:hover) .tw-node[data-n="9"],#compare:has(.hl.n10:hover) .tw-node[data-n="10"],
#compare:has(.hl.n11:hover) .tw-node[data-n="11"],#compare:has(.hl.n12:hover) .tw-node[data-n="12"],
#compare:has(.hl.n13:hover) .tw-node[data-n="13"],#compare:has(.hl.n14:hover) .tw-node[data-n="14"],
#compare:has(.hl.n15:hover) .tw-node[data-n="15"],#compare:has(.hl.n16:hover) .tw-node[data-n="16"],
#compare:has(.hl.n17:hover) .tw-node[data-n="17"],#compare:has(.hl.n18:hover) .tw-node[data-n="18"],
#compare:has(.hl.n19:hover) .tw-node[data-n="19"],#compare:has(.hl.n20:hover) .tw-node[data-n="20"],
#compare:has(.hl.n21:hover) .tw-node[data-n="21"],#compare:has(.hl.n22:hover) .tw-node[data-n="22"],
#compare:has(.hl.n23:hover) .tw-node[data-n="23"],#compare:has(.hl.n24:hover) .tw-node[data-n="24"],
#compare:has(.hl.n25:hover) .tw-node[data-n="25"]{filter:drop-shadow(0 2px 6px rgba(15,18,22,.3))}
.legend{
  display:flex; flex-wrap:wrap; gap:10px 22px; margin-top:20px;
  font-family:var(--mono); font-size:11.5px; color:var(--muted);
}
.legend .key{display:inline-flex; align-items:center; gap:8px}
.legend .sw{width:14px;height:14px;border-radius:50%;border:1.6px solid var(--ink);display:inline-block}
.legend .sw.sq{border-radius:3px}
.legend .sw.acc{border-color:var(--accent)} .legend .sw.amber{border-color:var(--amber)}
.legend .sw.dash{border-style:dashed; border-color:var(--amber); border-radius:3px}

/* ---------- demo ---------- */
.demo-grid{display:grid; grid-template-columns:1fr 1fr; gap:24px; margin-top:40px}
.term{
  background:var(--card); border:1px solid var(--hair); border-radius:16px; overflow:hidden;
  display:flex; flex-direction:column; margin:0; box-shadow:var(--shadow);
}
.term .term-tab{
  font-family:var(--mono); font-size:12.5px; letter-spacing:.1em; color:var(--muted);
  padding:11px 16px; border-bottom:1px solid var(--hair); display:flex; gap:8px; align-items:center;
  background:var(--bg-soft);
}
.term .term-tab .dot{width:8px;height:8px;border-radius:50%;background:var(--hair-2)}
.term .term-tab .dot.g{background:var(--accent)} .term .term-tab .dot.b{background:var(--amber)}
.term .term-body{padding:18px 18px 16px; font-size:14.5px; display:flex; flex-direction:column; gap:12px}
.q{align-self:flex-end; background:var(--neut-bg); border-radius:10px; padding:9px 13px; font-size:14px; color:var(--ink-2); max-width:88%}
.a{align-self:flex-start; border:1px solid var(--hair); border-radius:10px; padding:12px 14px; max-width:94%; background:var(--card)}
.a p{margin:0 0 6px}
.a .verdict{font-family:var(--mono); font-size:12px; margin-top:10px; letter-spacing:.02em}
.a .verdict.bad{color:var(--amber-ink)}
.a.prov{border-color:color-mix(in srgb,var(--accent) 40%,transparent)}
.chain{font-family:var(--mono); font-size:11.5px; line-height:1.9; color:var(--ink-2); margin-top:10px; border-top:1px dashed var(--hair-2); padding-top:10px}
.chain .k{color:var(--muted)}
.chain .g{color:var(--acc-ink)} .chain .am{color:var(--amber-ink)}
.strike{position:relative; white-space:nowrap}
.strike::after{content:""; position:absolute; left:-3px; right:-3px; top:52%; height:2px; background:var(--amber); transform:rotate(-2deg)}
.demo-cap{margin-top:20px; font-size:15px; color:var(--muted); max-width:60ch}

/* ---------- founder ---------- */
.founder{display:grid; grid-template-columns:240px 1fr; gap:36px; align-items:start; max-width:920px}
.founder .photo{margin:0}
.founder .photo img{border-radius:14px; border:1px solid var(--hair); box-shadow:var(--shadow)}
.founder .photo figcaption{font-family:var(--mono); font-size:11.5px; color:var(--muted); margin-top:10px}
.founder p{max-width:60ch; font-size:18px}

/* ---------- signup ---------- */
.signup .box{max-width:640px}
.choice{display:grid; gap:10px; margin:22px 0 18px}
.choice label{
  display:flex; gap:12px; align-items:flex-start; background:var(--card); border:1px solid var(--hair-2);
  border-radius:12px; padding:14px 16px; cursor:pointer; font-size:15.5px;
}
.choice label:has(input:checked){border-color:var(--accent); box-shadow:0 0 0 1px var(--accent) inset}
.choice input{margin-top:4px; accent-color:var(--accent)}
.choice .cl{flex:1}
.choice .cl small{display:block; color:var(--muted); font-size:13px; margin-top:2px}
.extra{display:none; margin:-6px 0 16px}
form.full:has(input[name=tag][value=alpha-tester]:checked) .extra{display:block}
.extra input{
  width:100%; font-family:var(--mono); font-size:14px; color:var(--ink);
  background:var(--card); border:1px dashed var(--hair-2); border-radius:10px; padding:12px 16px;
}
.priceline{margin-top:26px; display:flex; align-items:center; gap:12px; flex-wrap:wrap}

/* ---------- footer ---------- */
footer.site{padding:44px 0 54px; color:var(--muted); font-size:14px; border-top:1px solid var(--hair)}
footer.site .wrap{display:flex; gap:18px 34px; flex-wrap:wrap; align-items:baseline}
footer.site a{color:var(--muted)}
footer.site .privacy{margin-left:auto; font-family:var(--mono); font-size:11.5px}

/* ---------- reveal (progressive enhancement, no JS) ---------- */
@media (prefers-reduced-motion:no-preference){
  @supports (animation-timeline: view()){
    .rv{animation:rv-rise .7s cubic-bezier(.2,.6,.2,1) both; animation-timeline:view(); animation-range:entry 0% entry 32%}
    @keyframes rv-rise{from{opacity:0; translate:0 22px} to{opacity:1; translate:0 0}}
  }
}

/* ---------- responsive ---------- */
@media (max-width:1020px){
  .hero-grid{grid-template-columns:1fr}
  .hero-diagram{max-width:560px}
  .cards{grid-template-columns:1fr; max-width:560px}
  .compare-grid{grid-template-columns:1fr}
  .demo-grid{grid-template-columns:1fr}
  /* keep wrapping on tablets — portrait is fluid and stays under 60% */
  .failures li{grid-template-columns:110px 1fr}
  .failures .num{font-size:11.5px}
  .founder{grid-template-columns:1fr; gap:20px}
  .founder .photo{max-width:220px}
}
@media (max-width:560px){
  .twin-svg{min-width:600px}
  body{font-size:16.5px}
  /* below ~360px the portrait would exceed 60% of the column, so stack it full-width */
  @media (max-width:360px){
    .portrait{float:none; width:100%; max-width:100%; margin:0 0 20px}
  }
  nav.site a.navlink{display:none}
  footer.site .privacy{margin-left:0}
}

/* accessible-only label (Buttondown embed markup) */
.visually-hidden{
  position:absolute; width:1px; height:1px; padding:0; margin:-1px;
  overflow:hidden; clip:rect(0 0 0 0); white-space:nowrap; border:0;
}

/* subscribe success state: gradient pulse (default → lighter → default) */
.btn-ok{
  cursor:default; pointer-events:none; color:#fff;
  background:linear-gradient(100deg,var(--acc-1),var(--acc-2)) !important;
  background-size:200% 200% !important;
  animation:btn-pulse 1.6s ease-in-out;
}
@keyframes btn-pulse{
  0%   {background-position:0% 0%; filter:brightness(1)}
  45%  {background-position:100% 100%; filter:brightness(1.35)}
  100% {background-position:0% 0%; filter:brightness(1)}
}
@media (prefers-reduced-motion:reduce){.btn-ok{animation:none}}
.form-note{font-size:13.5px; color:var(--amber-ink); margin:10px 0 0; flex-basis:100%}