:root{
  --bg:#ffffff; --ink:#0d1526; --muted:#59637a; --line:#e7eaf1; --soft:#f5f7fb;
  --accent:#e85d1f; --accent-dark:#c74e15; --radius:18px; --max:760px;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{font-family:'Inter',system-ui,-apple-system,sans-serif;color:var(--ink);background:var(--bg);line-height:1.6;-webkit-font-smoothing:antialiased}
h1,h2,.brand,.card-title{font-family:'Sora',sans-serif}
:focus-visible{outline:3px solid var(--accent);outline-offset:2px}

.demo-banner{background:var(--ink);color:#dbe2f0;text-align:center;padding:10px 16px;font-size:.9rem}
.demo-banner strong{color:#ffab7a}

.top{max-width:var(--max);margin:0 auto;padding:20px 20px 0;display:flex;justify-content:space-between;align-items:center}
.brand{font-weight:800;font-size:1.1rem;text-decoration:none;color:var(--ink);letter-spacing:-.02em}
.top-tag{font-size:.82rem;font-weight:600;color:var(--accent);border:1px solid #ffd9c4;background:#fff4ec;padding:5px 12px;border-radius:999px}

.wrap{max-width:var(--max);margin:0 auto;padding:10px 20px 30px}
.intro{padding:28px 0 8px}
.intro h1{font-size:clamp(1.7rem,5.5vw,2.5rem);letter-spacing:-.025em;line-height:1.15}
.intro p{color:var(--muted);margin-top:12px;max-width:560px}

.progress{margin:22px 0 26px}
.progress-bar{height:8px;background:var(--soft);border:1px solid var(--line);border-radius:99px;overflow:hidden}
.progress-bar i{display:block;height:100%;width:16.6%;background:var(--accent);border-radius:99px;transition:width .35s ease}
.progress-label{font-size:.83rem;color:var(--muted);margin-top:7px;font-weight:500}

.step{display:none;border:1px solid var(--line);border-radius:var(--radius);padding:26px;background:#fff}
.step.active{display:block}
.step h2{font-size:1.35rem;letter-spacing:-.01em;margin-bottom:14px}
.sub-title{font-size:.95rem;margin:20px 0 10px;color:var(--ink)}
.hint{color:var(--muted);font-size:.95rem;margin-bottom:18px}
.error{color:#b3261e;font-weight:600;font-size:.92rem;margin-top:14px}

.cards{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.cards-3{grid-template-columns:repeat(3,1fr)}
.card{position:relative;display:block;border:2px solid var(--line);border-radius:14px;padding:16px;cursor:pointer;transition:border-color .15s ease,background .15s ease}
.card:hover{border-color:#ccd3e0}
.card input{position:absolute;opacity:0;pointer-events:none}
.card-title{display:block;font-weight:700;font-size:1.02rem}
.card-sub{display:block;color:var(--muted);font-size:.85rem;margin-top:2px}
.card:has(input:checked){border-color:var(--accent);background:#fff7f2}
.card:has(input:focus-visible){outline:3px solid var(--accent);outline-offset:2px}

.fields{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.field{display:block}
.field-wide{grid-column:1 / -1}
.field span{display:block;font-weight:600;font-size:.9rem;margin-bottom:6px}
.field input,.field select,.field textarea{width:100%;font:inherit;font-size:1rem;padding:13px 14px;border:1px solid var(--line);border-radius:12px;background:#fff;color:var(--ink)}
.field input:focus,.field select:focus,.field textarea:focus{outline:2px solid var(--accent);outline-offset:1px;border-color:transparent}

.room-diagram{display:flex;justify-content:center;margin:4px 0 20px}
.room-box{position:relative;width:230px;height:150px;border:2px solid var(--ink);border-radius:8px;background:var(--soft)}
.dim{position:absolute;font-size:.78rem;font-weight:600;color:var(--muted)}
.dim-top{top:-24px;left:0;right:0;text-align:center}
.dim-side{left:-52px;top:50%;transform:translateY(-50%) rotate(-90deg)}
.wall-tag{position:absolute;font-family:'Sora',sans-serif;font-weight:700;font-size:.85rem;background:var(--ink);color:#fff;width:24px;height:24px;border-radius:50%;display:flex;align-items:center;justify-content:center}
.wt-a{top:-12px;left:50%;transform:translateX(-50%)}
.wt-c{bottom:-12px;left:50%;transform:translateX(-50%)}
.wt-b{right:-12px;top:50%;transform:translateY(-50%)}
.wt-d{left:-12px;top:50%;transform:translateY(-50%)}

.wall{border:1px solid var(--line);border-radius:14px;padding:16px;margin-bottom:12px}
.wall-head{display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.wall-head label{display:flex;align-items:center;gap:9px;font-weight:600;cursor:pointer;font-size:1rem}
.wall-head input[type="checkbox"]{width:22px;height:22px;accent-color:var(--accent)}
.wall-len{color:var(--muted);font-size:.88rem;margin-left:auto}
.wall-counts{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:14px}
.wall.off .wall-counts{opacity:.38;pointer-events:none}
.count span{display:block;font-size:.82rem;font-weight:600;color:var(--muted);margin-bottom:5px}
.stepper{display:flex;align-items:center;gap:6px}
.stepper button{width:44px;height:44px;border-radius:12px;border:1px solid var(--line);background:#fff;font-size:1.25rem;font-weight:600;cursor:pointer;color:var(--ink)}
.stepper button:active{background:var(--soft)}
.stepper output{min-width:28px;text-align:center;font-weight:700;font-size:1.05rem}

.photo-drop{display:block;border:2px dashed #ccd3e0;border-radius:14px;padding:26px 18px;text-align:center;cursor:pointer;background:var(--soft)}
.photo-drop strong{display:block;font-family:'Sora',sans-serif;font-size:1.05rem}
.photo-drop span{color:var(--muted);font-size:.9rem}
.photo-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin-top:14px}
.photo-grid figure{border-radius:12px;overflow:hidden;border:1px solid var(--line)}
.photo-grid img{width:100%;height:88px;object-fit:cover;display:block}
.photo-grid figcaption{font-size:.72rem;color:var(--muted);padding:5px 8px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.privacy-note{margin-top:14px;font-size:.88rem;color:var(--muted);background:var(--soft);border:1px solid var(--line);border-radius:12px;padding:12px 14px}

.step-nav{display:flex;justify-content:space-between;gap:12px;margin-top:26px}
.btn{display:inline-block;font:inherit;font-weight:600;font-size:1rem;padding:14px 28px;border-radius:999px;cursor:pointer;text-decoration:none;border:1px solid transparent;min-height:52px}
.btn-primary{background:var(--ink);color:#fff}
.btn-primary:hover{background:#1b2947}
.btn-ghost{background:#fff;border-color:var(--line);color:var(--ink)}
.btn-ghost:hover{border-color:var(--ink)}

.summary{background:var(--soft);border:1px solid var(--line);border-radius:14px;padding:22px;white-space:pre-wrap;font-size:.96rem;line-height:1.65}
.result-actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:18px}
.copied{color:#177245;font-weight:600;margin-top:12px;font-size:.92rem}
.live-note{margin-top:16px;color:var(--muted);font-size:.92rem}

.foot{border-top:1px solid var(--line);margin-top:26px}
.foot p{max-width:var(--max);margin:0 auto;padding:10px 20px;color:var(--muted);font-size:.88rem}
.foot p:first-child{padding-top:20px}
.foot a{color:var(--accent);font-weight:600;text-decoration:none}

@media (max-width:560px){
  .cards,.cards-3,.fields{grid-template-columns:1fr}
  .wall-counts{grid-template-columns:1fr}
  .photo-grid{grid-template-columns:repeat(3,1fr)}
  .step{padding:20px 16px}
  .step-nav .btn{padding:14px 20px}
  .dim-side{left:-44px}
}
@media (prefers-reduced-motion:reduce){
  .progress-bar i{transition:none}
}

/* Standalone release additions: per-field errors + helper note */
.field-error{margin-top:6px;font-size:.85rem}
.field input[aria-invalid="true"]{border-color:#b3261e;outline-color:#b3261e}
.hint.helper{margin-top:-8px;font-size:.88rem;background:var(--soft);border:1px solid var(--line);border-radius:12px;padding:10px 14px}