:root{--bg:#fafaf9;--ink:#1c1917;--mute:#78716c;--line:#e7e5e4;--soft:#f5f5f4;--warn:#fef3c7;--warnb:#d97706}
*{box-sizing:border-box}body{margin:0;font-family:-apple-system,Segoe UI,Inter,Helvetica,Arial,sans-serif;background:var(--bg);color:var(--ink);line-height:1.5}
header.top{padding:28px 40px;border-bottom:1px solid var(--line);background:#fff}header.top h1{margin:0;font-size:20px}header.top p{margin:4px 0 0;color:var(--mute);font-size:14px}
.tag{display:inline-block;font-size:11px;padding:2px 8px;border-radius:99px;background:var(--warn);color:#92400e;font-weight:600}
section.part{padding:40px;max-width:1200px;margin:0 auto}section.part>h2{font-size:15px;text-transform:uppercase;letter-spacing:.08em;color:var(--mute);margin:0 0 20px}
.flow{display:grid;grid-template-columns:repeat(5,1fr);gap:14px}
.node{background:#fff;border:1.5px dashed #a8a29e;border-radius:10px;padding:12px;font-size:13px;min-height:88px}
.node b{display:block;margin-bottom:4px}.node small{color:var(--mute)}.node.later{opacity:.45;border-style:dotted;background:var(--soft)}.node.alt{border:1.5px solid #78716c}
.ev{display:inline-block;margin:6px 3px 0 0;font-family:ui-monospace,Menlo,monospace;font-size:10.5px;background:#ecfdf5;color:#065f46;border:1px solid #a7f3d0;border-radius:4px;padding:1px 5px}
.lane{grid-column:span 5;font-size:11px;text-transform:uppercase;letter-spacing:.08em;color:var(--mute);margin-top:10px}
.legend{margin-top:18px;font-size:12px;color:var(--mute);display:flex;gap:18px;flex-wrap:wrap}.sw{width:14px;height:14px;border-radius:3px;display:inline-block;vertical-align:middle;margin-right:6px}
.device{background:#fff;border:1px solid var(--line);border-radius:14px;box-shadow:0 10px 30px rgba(0,0,0,.04);overflow:hidden}
.bar{display:flex;align-items:center;justify-content:space-between;padding:14px 22px;border-bottom:1px solid var(--line)}.logo{font-weight:700;font-size:15px}.logo span{color:var(--mute);font-weight:400}
.stepper{display:flex;gap:8px;align-items:center;font-size:12px;color:var(--mute)}.stepper .s{display:flex;align-items:center;gap:6px}
.dot{width:22px;height:22px;border-radius:50%;border:1.5px solid var(--line);display:grid;place-items:center;font-size:11px}
.s.on{color:var(--ink)}.s.on .dot{background:var(--ink);color:#fff;border-color:var(--ink)}.s.done .dot{background:#d6d3d1;border-color:#d6d3d1;color:var(--ink)}.ln{width:24px;height:1px;background:var(--line)}
.screen{display:none;padding:44px 56px;min-height:520px}.screen.on{display:block}
h3{font-size:28px;margin:0 0 8px;letter-spacing:-.01em}.lead{color:var(--mute);font-size:16px;max-width:620px;margin:0}
.btn{font:inherit;font-size:14px;padding:10px 18px;border-radius:8px;border:1px solid var(--ink);background:var(--ink);color:#fff;cursor:pointer}.btn.ghost{background:#fff;color:var(--ink);border-color:var(--line)}.btn.sm{padding:6px 12px;font-size:13px}
.link{background:none;border:none;color:var(--mute);text-decoration:underline;cursor:pointer;font:inherit;font-size:13px;padding:0}
.three{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin-top:28px}.feat{border:1px solid var(--line);border-radius:10px;padding:18px;font-size:14px}.feat b{display:block}
.tabs{display:flex;gap:4px;border-bottom:1px solid var(--line);margin:22px 0 16px}.tabs button{font:inherit;font-size:14px;background:none;border:none;padding:10px 14px;cursor:pointer;color:var(--mute);border-bottom:2px solid transparent}.tabs button.on{color:var(--ink);border-color:var(--ink)}
textarea,input[type=text],input[type=email]{width:100%;font:inherit;font-size:14px;padding:11px;border:1px solid var(--line);border-radius:8px;background:#fff}textarea{min-height:120px;resize:vertical}
label.f{display:block;font-size:13px;font-weight:600;margin:14px 0 4px}
.drop{border:1.5px dashed #d6d3d1;border-radius:10px;padding:36px;text-align:center;color:var(--mute);font-size:14px}
.note{background:var(--warn);border-left:3px solid var(--warnb);padding:10px 14px;border-radius:6px;font-size:13px;color:#78350f;margin:18px 0}
.ex{font-size:11px;color:var(--mute);text-transform:uppercase;letter-spacing:.06em;margin-bottom:4px}
.spinner{width:36px;height:36px;border:3px solid var(--line);border-top-color:var(--ink);border-radius:50%;animation:sp 1s linear infinite;margin:0 auto 18px}@keyframes sp{to{transform:rotate(360deg)}}
.skel{height:12px;background:var(--soft);border-radius:4px;margin:8px 0}
.brief{display:grid;grid-template-columns:200px 1fr;border:1px solid var(--line);border-radius:12px;overflow:hidden;margin-top:20px}
.brief div{padding:12px 16px;border-bottom:1px solid var(--line);font-size:14px}.brief .k{background:var(--soft);font-weight:600;font-size:13px}.brief .usecase{background:#fffbeb}
[contenteditable]{outline:none;border-radius:4px}[contenteditable]:hover{background:#fafaf9}[contenteditable]:focus{background:#fff;box-shadow:0 0 0 1.5px #a8a29e}
.pcard{border:1px solid var(--line);border-radius:12px;padding:18px;font-size:13px;align-self:start}
.hd{display:flex;gap:10px;align-items:center;margin-bottom:8px}.av{width:36px;height:36px;border-radius:50%;display:grid;place-items:center;font-weight:600;font-size:13px;color:#fff;flex:none}
.pcard h4{margin:12px 0 2px;font-size:11px;text-transform:uppercase;letter-spacing:.06em;color:var(--mute);font-weight:600}
.more{margin-top:12px;font-size:12px}.full{display:none}.pcard.open .full{display:block}
.jt{width:100%;border-collapse:collapse;font-size:12px;margin-top:4px}.jt td{border-top:1px solid var(--line);padding:5px 4px;vertical-align:top}.jt td:first-child{width:50%}
.actions{display:flex;gap:10px;justify-content:space-between;align-items:center;margin-top:24px;flex-wrap:wrap}
.modal{position:fixed;inset:0;background:rgba(28,25,23,.35);display:none;place-items:center;z-index:9}.modal.on{display:grid}.modal .box{background:#fff;border-radius:14px;padding:30px;max-width:420px;width:92%}
.chat{display:grid;grid-template-columns:220px 1fr;gap:24px;margin-top:12px}.side{border-right:1px solid var(--line);padding-right:18px;font-size:13px}
.who{display:flex;align-items:center;gap:8px;padding:8px;border-radius:8px;cursor:pointer}.who.on{background:var(--soft)}.who .av,.m .av{width:28px;height:28px;font-size:11px}
.toggle{display:flex;border:1px solid var(--line);border-radius:8px;overflow:hidden;margin-bottom:14px}.toggle button{flex:1;font:inherit;font-size:12px;padding:6px;border:none;background:#fff;cursor:pointer}.toggle button.on{background:var(--ink);color:#fff}
.msgs{height:320px;overflow:auto}.m{display:flex;gap:10px;margin-bottom:14px;font-size:14px}.m.me{justify-content:flex-end}.m.me .b{background:var(--ink);color:#fff}
.b{background:var(--soft);padding:10px 14px;border-radius:12px;max-width:80%}.b small{display:block;color:var(--mute);font-size:11px}
.composer{display:flex;gap:8px;margin-top:10px}.chips{display:flex;gap:6px;flex-wrap:wrap;margin-top:8px}.chip{font-size:12px;border:1px solid var(--line);border-radius:99px;padding:4px 10px;cursor:pointer}
.log{margin-top:14px;font-family:ui-monospace,Menlo,monospace;font-size:11px;color:#065f46;background:#ecfdf5;border:1px solid #a7f3d0;border-radius:8px;padding:8px 12px;max-height:110px;overflow:auto}
footer{padding:30px;text-align:center;color:var(--mute);font-size:12px}

/* --- app additions --- */
.app{max-width:1100px;margin:32px auto;padding:0 16px}
.err{color:#b91c1c;font-size:13px;min-height:16px;margin-top:8px}
.btn[disabled]{opacity:.5;cursor:wait}
.counter{font-size:12px;color:var(--mute);margin-top:6px}
.drop.over{border-color:var(--ink);background:var(--soft)}
.b{white-space:pre-wrap}
@media (max-width:800px){.three{grid-template-columns:1fr}.chat{grid-template-columns:1fr}.side{border-right:none;padding-right:0}.screen{padding:28px 20px}.brief{grid-template-columns:1fr}}

.sessdl{font-size:13px;color:var(--mute);margin:-6px 0 6px}.sessdl .err{display:inline;margin-left:8px}
.endpanel{border:1px solid var(--line);border-radius:12px;padding:22px;margin-top:16px;background:#fff}.endpanel h3{font-size:20px;margin:0 0 4px}.endpanel .sub{color:var(--mute);font-size:14px;margin:0 0 16px}
.endpanel .row{display:flex;gap:18px;align-items:flex-start;flex-wrap:wrap}.endpanel .col{display:flex;flex-direction:column;gap:6px}
.fmt{display:flex;gap:4px}.fmt button{font:inherit;font-size:12px;border:1px solid var(--line);background:#fff;border-radius:99px;padding:3px 10px;cursor:pointer}.fmt button.on{background:var(--ink);color:#fff;border-color:var(--ink)}
.cap{font-size:12px;color:var(--mute)}.ok{font-size:14px;padding:12px 14px;background:#ecfdf5;border:1px solid #a7f3d0;border-radius:10px;color:#065f46}

/* brief gaps (option B) */
.brief .gap{background:#fffbeb;box-shadow:inset 3px 0 0 #f59e0b}
.brief [contenteditable]:empty:before{content:attr(data-hint);color:#b45309;font-style:italic}
.brief .key{background:#eef2ff;box-shadow:inset 3px 0 0 #4f46e5}.brief .k.key{color:#3730a3}
.brief .keyhint{display:block;font-size:12px;color:#4f46e5;font-weight:400;margin-top:2px}
.gapsum{font-size:13px;color:#92400e;margin-top:14px}
.nudge{font-size:13px;color:#92400e;background:#fffbeb;border:1px solid #fde68a;border-radius:8px;padding:8px 12px;margin-top:12px;display:none}