/* A4A concept 2026-10-11 — "for you / for your agent".
   Warm human story on the left, precise agent instruction on the right. */
@font-face { font-family:"Manrope"; src:url("assets/fonts/Manrope-Variable.ttf?v=20261015T022320Z") format("truetype"); font-weight:200 800; font-display:swap; }
@font-face { font-family:"Pangolin"; src:url("assets/fonts/Pangolin-Regular.ttf?v=20261015T022320Z") format("truetype"); font-weight:400; font-display:swap; }

:root {
  --pad:clamp(18px,5vw,80px);
  --mono:ui-monospace,"Cascadia Mono",Consolas,"SFMono-Regular",Menlo,monospace;
}
*,*::before,*::after { box-sizing:border-box; }
html { -webkit-text-size-adjust:100%; scroll-behavior:smooth; scroll-padding-top:16px; }
@media (prefers-reduced-motion:reduce) { html { scroll-behavior:auto; } }
body { margin:0; background:var(--paper); color:var(--ink); font:400 16px/1.55 "Manrope",system-ui,sans-serif; font-feature-settings:"ss01"; -webkit-font-smoothing:antialiased; }
img { display:block; max-width:100%; }
a { color:inherit; }
:focus-visible { outline:2px solid var(--accent); outline-offset:3px; border-radius:6px; }
h1,h2,h3,h4,p,ol,ul,figure { margin:0; }
.wrap { width:100%; max-width:1440px; margin-inline:auto; padding-inline:var(--pad); }
.skip { position:absolute; left:12px; top:-60px; background:var(--ink); color:#fff; padding:10px 14px; border-radius:8px; z-index:10; }
.skip:focus { top:12px; }

/* ---------- header ---------- */
.top { border-bottom:1px solid var(--line); }
.top-row { display:flex; align-items:center; gap:24px; min-height:72px; }
.mark { display:flex; align-items:baseline; gap:12px; text-decoration:none; margin-right:auto; }
.mark b { font-weight:800; font-size:24px; letter-spacing:-.04em; }
.mark span { font:12px/1 var(--mono); color:var(--muted); letter-spacing:.02em; }
#nav { display:flex; gap:clamp(16px,2.4vw,34px); }
#nav a { text-decoration:none; font-size:14px; font-weight:500; color:var(--muted); padding-block:10px; }
#nav a:hover { color:var(--ink); }
.menu { display:none; }

/* ---------- hero ---------- */
.hero { padding-block:clamp(28px,4.6vh,56px) clamp(56px,8vh,96px); }
.hero-grid { display:grid; grid-template-columns:minmax(0,1.32fr) minmax(360px,.88fr); grid-template-areas:"head head" "human agent"; column-gap:clamp(40px,5vw,88px); }
.hero-head { grid-area:head; margin-bottom:clamp(22px,3vh,34px); }
.kicker { font:500 12px/1.4 var(--mono); letter-spacing:.08em; text-transform:uppercase; color:var(--muted); margin-bottom:18px; display:flex; align-items:center; gap:10px; }
.kicker::before { content:""; width:22px; height:2px; background:var(--accent); }
h1 { font-weight:650; font-size:clamp(36px,5.05vw,78px); line-height:1.02; letter-spacing:-.045em; }
.hero-human { grid-area:human; min-width:0; }
.lede { font-size:clamp(18px,1.55vw,22px); line-height:1.45; font-weight:500; letter-spacing:-.01em; max-width:30em; }
.lede-note { margin-top:10px; font-size:14px; color:var(--muted); }
.actions { display:flex; flex-wrap:wrap; gap:12px 22px; align-items:center; margin-top:26px; }
.btn { display:inline-flex; align-items:center; justify-content:center; gap:14px; min-height:50px; padding:0 22px; border-radius:var(--radius-control); font:600 15px/1 "Manrope",sans-serif; text-decoration:none; border:1px solid transparent; cursor:pointer; }
.btn-primary { background:var(--accent); color:#fff; }
.btn-primary:hover { background:var(--accent-ink); }
.btn-ghost { border-color:var(--line); color:var(--ink); background:transparent; }
.btn-ghost:hover { border-color:var(--ink); }
.to-connect { display:none; }

/* scene: two separate homes, agents talk across the gap */
.scene { margin-top:clamp(18px,3vh,30px); }
.scene-stage { position:relative; padding-top:88px; --talk-row:1; }
.art { position:relative; aspect-ratio:1/.55; }
.island { position:absolute; width:52%; aspect-ratio:991.5/793; overflow:hidden; }
.island-left { left:0; top:23.8%; }
.island-right { right:0; top:0; }
.stack { position:absolute; top:0; height:100%; width:200%; }
.island-left .stack { left:0; }
.island-right .stack { left:-100%; }
.stack img { position:absolute; inset:0; width:100%; height:100%; user-select:none; pointer-events:none; }
.island-left .layer-base { -webkit-mask-image:radial-gradient(ellipse 7.9% 22.1% at 36.3% 42.2%,transparent 90%,#000 90%); mask-image:radial-gradient(ellipse 7.9% 22.1% at 36.3% 42.2%,transparent 90%,#000 90%); }
.island-left .layer-agents { -webkit-mask-image:radial-gradient(ellipse 7.9% 22.1% at 36.3% 42.2%,#000 90%,transparent 100%); mask-image:radial-gradient(ellipse 7.9% 22.1% at 36.3% 42.2%,#000 90%,transparent 100%); }
.island-left .layer-heads { -webkit-mask-image:radial-gradient(ellipse 10% 26% at 20% 40%,#000 90%,transparent 100%); mask-image:radial-gradient(ellipse 10% 26% at 20% 40%,#000 90%,transparent 100%); }
.island-right .layer-base { -webkit-mask-image:radial-gradient(ellipse 7.9% 22.1% at 61.5% 43.5%,transparent 90%,#000 90%); mask-image:radial-gradient(ellipse 7.9% 22.1% at 61.5% 43.5%,transparent 90%,#000 90%); }
.island-right .layer-agents { -webkit-mask-image:radial-gradient(ellipse 7.9% 22.1% at 61.5% 43.5%,#000 90%,transparent 100%); mask-image:radial-gradient(ellipse 7.9% 22.1% at 61.5% 43.5%,#000 90%,transparent 100%); }
.island-right .layer-heads { -webkit-mask-image:radial-gradient(ellipse 10% 26% at 78% 40%,#000 90%,transparent 100%); mask-image:radial-gradient(ellipse 10% 26% at 78% 40%,#000 90%,transparent 100%); }


.bubble { position:absolute; z-index:2; isolation:isolate; display:flex; flex-direction:column; gap:3px; padding:10px 17px 11px; background:#fff; border:1.6px solid var(--ink); border-radius:18px; white-space:nowrap; }
.bubble.shaped { background:none; border-color:transparent; }
.bubble-shape { position:absolute; left:-1.6px; top:-1.6px; overflow:visible; z-index:-1; pointer-events:none; }
.bubble-shape path { fill:#fff; stroke:var(--ink); stroke-width:1.6; stroke-linejoin:round; }
.who { font:600 10.5px/1.2 "Manrope",sans-serif; letter-spacing:.02em; color:var(--muted); }
.say { font:400 19px/1.2 "Pangolin","Comic Sans MS",cursive; color:var(--ink); }
.bubble-send { left:16%; top:4px; }
.bubble-reply { left:50%; top:18px; }
.scene figcaption { margin-top:14px; font-size:13px; color:var(--muted); max-width:34em; }

/* terminal: the instruction is addressed to the agent */
.hero-agent { grid-area:agent; min-width:0; align-self:start; scroll-margin-top:16px; }
.term { background:var(--term); color:var(--term-ink); border-radius:20px; overflow:hidden; box-shadow:0 30px 60px -38px rgba(23,22,31,.55); }
.term-bar { display:flex; align-items:center; gap:14px; padding:14px 20px; border-bottom:1px solid var(--term-line); font:12px/1 var(--mono); color:var(--term-muted); }
.dots { display:flex; gap:6px; }
.dots i { width:9px; height:9px; border-radius:50%; background:#3a3848; }
.term-body { padding:26px 26px 22px; }
.term h2 { font-size:clamp(24px,2vw,30px); line-height:1.15; letter-spacing:-.035em; font-weight:650; }
.term-lede { margin-top:12px; font-size:15px; line-height:1.55; color:var(--term-muted); }
.prompt { margin-top:20px; padding:16px 18px; border-radius:var(--radius-control); background:var(--term-2); border:1px solid var(--term-line); font:13px/1.65 var(--mono); }
.prompt-line { color:#fff; }
.caret { color:var(--term-hot); margin-right:4px; }
.prompt ol { margin-top:8px; padding-left:22px; color:var(--term-muted); }
.prompt li::marker { color:var(--term-hot); }
.copy-row { display:flex; flex-wrap:wrap; align-items:center; gap:12px 20px; margin-top:20px; }
.btn-copy { background:#fff; color:var(--term); min-height:50px; }
.btn-copy:hover { background:#E5E8FA; }
.btn-copy[disabled] { opacity:.7; cursor:progress; }
.term-link { font-size:14px; color:var(--term-ink); text-underline-offset:4px; padding-block:12px; }
.copy-status { font-size:13px; color:#9FE0B5; margin-top:10px; }
.copy-status:empty { display:none; }
.copy-fallback { width:100%; min-height:140px; margin-top:12px; padding:12px; border-radius:10px; background:var(--term-2); color:var(--term-ink); border:1px solid var(--term-line); font:12px/1.5 var(--mono); resize:vertical; }
.term-meta { margin-top:14px; font-size:12.5px; line-height:1.55; color:var(--term-muted); }
.term-foot { display:flex; flex-wrap:wrap; align-items:center; gap:0 18px; padding:14px 26px 8px; border-top:1px solid var(--term-line); font-size:14px; color:var(--term-muted); }
.foot-label { flex:1 1 100%; font:12px/1.3 var(--mono); color:var(--term-muted); }
.term-foot a { color:var(--term-ink); text-decoration:none; padding-block:12px; }
.term-foot a:hover { text-decoration:underline; text-underline-offset:4px; }

/* ---------- block 01: why ---------- */
.why { padding-block:clamp(72px,10vw,140px); border-top:1px solid var(--line); background:linear-gradient(var(--paper-2),var(--paper) 520px); }
.block-head { max-width:820px; }
.num { color:var(--accent); font-weight:700; }
.block-head .kicker::before { display:none; }
h2 { font-weight:650; font-size:clamp(30px,3.9vw,56px); line-height:1.06; letter-spacing:-.04em; }
.block-lede { margin-top:18px; font-size:clamp(17px,1.4vw,20px); line-height:1.5; color:var(--muted); max-width:34em; }

.routes { display:grid; grid-template-columns:1.25fr 1fr; gap:20px; margin-top:clamp(36px,5vw,60px); }
.route { border-radius:var(--radius-card); padding:clamp(22px,2.4vw,34px); display:flex; flex-direction:column; }
.route-manual .chain { margin-block:auto; padding-block:12px; }
.route-manual { background:transparent; border:1.5px dashed var(--line-strong); }
.route-direct { background:var(--card); border:1px solid var(--line); box-shadow:0 24px 50px -40px rgba(28,27,34,.35); }
.route-title { font:600 12px/1 var(--mono); letter-spacing:.08em; text-transform:uppercase; color:var(--muted); }
.route-direct .route-title { color:var(--accent); }
.route-note { margin-top:24px; font-size:15px; line-height:1.5; color:var(--muted); }
.route-direct .route-note { color:var(--ink); }

.ava { --s:56px; flex:none; display:block; width:var(--s); height:var(--s); border-radius:50%; background:#EADFCF url("assets/separate-workspaces-warm.webp?v=20261015T022320Z") no-repeat; background-size:calc(var(--s) * 1983 / var(--r)) auto; background-position:calc(var(--s) * (var(--r) / 2 - var(--cx)) / var(--r)) calc(var(--s) * (var(--r) / 2 - var(--cy)) / var(--r)); box-shadow:0 0 0 3px var(--paper), 0 0 0 4px var(--line); }
.ava-girl { --cx:415; --cy:300; --r:300; }
.ava-man { --cx:1565; --cy:285; --r:300; }
.ava-agent-l { --cx:713; --cy:278; --r:190; background-color:#F4EEE6; }
.ava-agent-r { --cx:1232; --cy:292; --r:190; background-color:#F4EEE6; }
.ava-chat { background:#E8E2D8; position:relative; }
.ava-chat i { position:absolute; width:44%; height:30%; border-radius:8px; background:#fff; border:1.5px solid #B9AF9F; }
.ava-chat i:first-child { left:16%; top:24%; border-bottom-left-radius:2px; }
.ava-chat i:last-child { right:16%; top:47%; background:#D6DBF6; border-color:#9BA6E6; border-bottom-right-radius:2px; }

.chain { list-style:none; padding:0; margin-top:28px; display:flex; }
.chain li { position:relative; flex:1 1 0; min-width:0; display:flex; flex-direction:column; align-items:center; text-align:center; gap:2px; }
.chain li .ava { margin-bottom:10px; }
.chain li:not(:last-child)::after { content:""; position:absolute; top:27px; left:calc(50% + 36px); right:calc(-50% + 36px); border-top:2px dashed #BDB2A1; }
.chain li:not(:last-child)::before { content:""; position:absolute; top:23px; right:calc(-50% + 34px); border:5px solid transparent; border-left:7px solid #BDB2A1; border-right:0; }
.chain b { font-size:14px; font-weight:650; }
.chain small { font-size:13px; color:var(--muted); }

.direct { display:grid; grid-template-columns:1fr minmax(120px,1.3fr) 1fr; align-items:end; margin-top:28px; }
.side { display:flex; flex-direction:column; align-items:center; text-align:center; }
.side b { font-size:14px; font-weight:650; margin-top:8px; }
.side .ava:first-child { --s:44px; }
.tick { display:flex; flex-direction:column; align-items:center; margin:6px 0 8px; font-size:12.5px; line-height:1.3; color:var(--muted); }
.tick::before, .tick::after { content:""; width:0; height:14px; border-left:1.5px solid var(--line); }
.tick::before { margin-bottom:6px; }
.tick::after { margin-top:6px; }
.wire { position:relative; height:56px; margin-bottom:30px; }
.wire::before { content:""; position:absolute; left:-6px; right:-6px; top:50%; height:4px; margin-top:-2px; border-radius:4px; background:var(--accent); }
.wire-label { position:absolute; left:50%; top:50%; transform:translate(-50%,-50%); background:var(--accent); color:#fff; font:700 13px/1 var(--mono); letter-spacing:.06em; padding:8px 12px; border-radius:999px; box-shadow:0 0 0 4px var(--card); }
.wire-cargo { position:absolute; left:0; right:0; top:calc(50% + 20px); text-align:center; font-size:12.5px; color:var(--muted); }

.cases-head { display:flex; flex-wrap:wrap; align-items:baseline; justify-content:space-between; gap:8px 24px; margin-top:clamp(64px,7vw,100px); padding-top:26px; border-top:1px solid var(--line); }
.cases-head h3 { font-size:clamp(22px,2vw,28px); font-weight:650; letter-spacing:-.03em; }
.cases-head p { color:var(--muted); font-size:15px; }
.cases { list-style:none; padding:0; margin-top:26px; display:grid; grid-template-columns:repeat(3,minmax(0,1fr)); gap:20px; }
.case { background:var(--card); border:1px solid var(--line); border-radius:20px; padding:24px 22px 22px; display:flex; flex-direction:column; }
.case-tag { font:500 11.5px/1.3 var(--mono); letter-spacing:.06em; text-transform:uppercase; color:var(--muted); }
.case h4 { margin-top:10px; font-size:19px; line-height:1.3; font-weight:650; letter-spacing:-.02em; }
.talk { margin-top:auto; padding-top:20px; display:flex; flex-direction:column; gap:8px; }
.line { max-width:88%; padding:9px 14px 10px; border-radius:var(--radius-inner); font:400 17px/1.25 "Pangolin","Comic Sans MS",cursive; }
.line span { display:block; font:600 10.5px/1.3 "Manrope",sans-serif; color:var(--muted); letter-spacing:.02em; margin-bottom:3px; }
.line-a { align-self:flex-start; background:var(--paper-2); border-bottom-left-radius:5px; }
.line-b { align-self:flex-end; background:var(--accent-soft); border-bottom-right-radius:5px; }
.file { align-self:flex-start; display:inline-flex; align-items:center; gap:9px; margin-left:14px; padding:7px 12px; border:1px dashed #C3B9A9; border-radius:10px; font-size:12.5px; color:var(--muted); }
.file i { font-style:normal; color:var(--accent); font-weight:700; }

.boundary { display:flex; flex-wrap:wrap; align-items:center; justify-content:space-between; gap:12px 32px; margin-top:28px; padding:20px 0 0; }
.boundary p { max-width:58em; font-size:14.5px; line-height:1.6; color:var(--muted); }
.boundary b { color:var(--ink); font-weight:650; }
.text-link { font-size:14px; font-weight:600; color:var(--accent-ink); text-underline-offset:4px; padding-block:12px; }

.proto-note { padding-block:28px 56px; }
.proto-note .wrap > * { max-width:900px; }
.proto-note { font-size:13.5px; color:var(--muted); line-height:1.6; }
.proto-note .wrap { border-top:1px dashed var(--line-strong); padding-top:24px; }
.proto-label { font:600 11px/1 var(--mono); letter-spacing:.08em; text-transform:uppercase; color:var(--warning); margin-bottom:10px; }
.proto-links { margin-top:8px; }
.proto-links a { color:var(--accent-ink); }

/* ---------- tablet ---------- */
@media (max-width:1100px) {
  .hero-grid { grid-template-columns:minmax(0,1.2fr) minmax(330px,.95fr); column-gap:36px; }
  .term-body { padding:22px 22px 18px; }
  .term-foot { padding-inline:22px; }
  .routes { grid-template-columns:1fr; }
  .cases { grid-template-columns:1fr 1fr; }
  .cases .case:last-child { grid-column:1/-1; }
}
@media (max-width:1100px) {
  .hero-grid { grid-template-columns:1fr; grid-template-areas:"head" "human" "agent"; }
  .hero-agent { margin-top:44px; max-width:640px; }
  .to-connect { display:inline-flex; }
  .scene { max-width:760px; }
}
@media (max-width:900px) {
  #nav { gap:18px; }
  #nav a { font-size:13px; }
}

/* ---------- phone ---------- */
@media (max-width:700px) {
  .top-row { min-height:62px; flex-wrap:wrap; gap:0; }
  .mark span { display:none; }
  .menu { display:inline-flex; align-items:center; min-height:44px; padding:0 16px; border:1px solid var(--line); border-radius:10px; background:transparent; font:600 14px/1 "Manrope",sans-serif; color:var(--ink); cursor:pointer; }
  .js #nav { display:none; }
  #nav { width:100%; flex-direction:column; gap:0; padding-bottom:10px; }
  .js #nav[data-open] { display:flex; }
  #nav a { font-size:16px; padding:12px 0; border-top:1px solid var(--line); color:var(--ink); }
  .hero { padding-top:30px; }
  h1 { font-size:clamp(31px,9.6vw,48px); line-height:1.05; letter-spacing:-.04em; }
  .kicker { margin-bottom:14px; font-size:11px; }
  .lede { font-size:17px; }
  .lede-note { font-size:13px; }
  .br-wide { display:none; }
  .actions { gap:10px; margin-top:22px; }
  .actions .btn { flex:1 1 auto; padding:0 16px; }
  .scene { margin-inline:calc(-1 * var(--pad)); margin-top:26px; }
  .scene-stage { padding-top:0; --talk-row:0; }
  .art { aspect-ratio:1/.83; }
  .island { width:60%; }
  .island-left { top:39%; }
  .island-right { top:3%; }
  .bubble { padding:8px 13px 9px; border-radius:var(--radius-inner); }
  .say { font-size:17px; }
  .who { font-size:10px; }
  .bubble-send { left:auto; right:3%; top:76%; }
  .bubble-reply { left:4%; top:5%; }
  .scene figcaption { padding-inline:var(--pad); }
  .hero-agent { margin-top:36px; }
  .term { border-radius:var(--radius-inner); }
  .term-body { padding:20px 18px 16px; }
  .term h2 { font-size:24px; }
  .prompt { padding:14px 14px; font-size:12.5px; }
  .prompt ol { padding-left:20px; }
  .copy-row .btn-copy { flex:1 1 100%; }
  .term-link { padding-block:8px; }
  .term-foot { padding:6px 18px 8px; gap:0 14px; }

  .routes { gap:16px; }
  .chain { flex-direction:column; gap:14px; margin-top:22px; }
  .chain li { flex-direction:row; text-align:left; gap:0 14px; align-items:center; display:grid; grid-template-columns:auto 1fr; grid-template-rows:auto auto; }
  .chain li .ava { --s:44px; grid-row:1/3; margin:0; }
  .chain li b { align-self:end; }
  .chain li small { align-self:start; }
  .chain li:not(:last-child)::after { top:46px; bottom:-14px; left:21px; right:auto; border-top:0; border-left:2px dashed #BDB2A1; height:auto; }
  .chain li:not(:last-child)::before { display:none; }
  .direct { grid-template-columns:1fr minmax(96px,1fr) 1fr; }
  .side .ava { --s:46px; }
  .side .ava:first-child { --s:38px; }
  .side b { font-size:13px; }
  .tick { font-size:11.5px; max-width:7.5em; line-height:1.25; }
  .tick::before, .tick::after { height:10px; }
  .wire { margin-bottom:28px; }
  .wire-cargo { font-size:11.5px; line-height:1.25; top:calc(50% + 19px); }
  .cases { grid-template-columns:1fr; gap:14px; }
  .case { padding:20px 18px 18px; }
  .case h4 { font-size:18px; }
  .line { font-size:16px; }
}
@media (max-width:360px) {
  .btn { font-size:14px; }
  .say { font-size:16px; }
  .bubble { padding:7px 11px 8px; }
  .term-foot { font-size:12.5px; gap:0 12px; }
}