:root{
  --bg:#f7f7f8; --panel:#ffffff; --text:#111827; --muted:#6b7280;
  --border:#e5e7eb; --accent:#111827; --accent-text:#ffffff;
}
@media (prefers-color-scheme: dark){
  :root:not([data-theme="light"]){
    --bg:#0b0d12; --panel:#151821; --text:#f3f4f6; --muted:#9ca3af;
    --border:#262b36; --accent:#f3f4f6; --accent-text:#111827;
  }
}
:root[data-theme="dark"]{
  --bg:#0b0d12; --panel:#151821; --text:#f3f4f6; --muted:#9ca3af;
  --border:#262b36; --accent:#f3f4f6; --accent-text:#111827;
}

*{box-sizing:border-box}
body{
  margin:0; background:var(--bg); color:var(--text);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  line-height:1.5;
}
.wrap{max-width:880px; margin:0 auto; padding-inline:16px}

.site-header{border-bottom:1px solid var(--border); padding-block:14px}
.site-header .wrap{display:flex; align-items:center; justify-content:space-between}
.brand{font-weight:700; text-decoration:none; color:var(--text); font-size:1.1rem}
.site-header nav a{color:var(--muted); text-decoration:none; margin-left:18px; font-size:0.9rem}
.site-header nav a:hover{color:var(--text)}

h1{font-size:1.8rem; margin-top:32px; margin-bottom:6px}
.subtitle{color:var(--muted); margin-top:0; margin-bottom:24px}

.app-grid{display:grid; grid-template-columns:1fr 1fr; gap:20px; margin-bottom:8px}
@media (max-width:640px){ .app-grid{grid-template-columns:1fr} }

.panel{
  background:var(--panel); border:1px solid var(--border); border-radius:12px;
  padding:20px;
}
.panel label{display:block; font-size:0.85rem; font-weight:600; margin-bottom:6px; color:var(--muted)}
.panel textarea, .panel select, .panel input[type="file"]{
  width:100%; border:1px solid var(--border); border-radius:8px; padding:10px;
  background:var(--bg); color:var(--text); font-size:0.95rem; font-family:inherit;
  margin-bottom:14px;
}
.panel input[type="color"]{
  width:100%; height:40px; border:1px solid var(--border); border-radius:8px;
  background:var(--bg); margin-bottom:14px; padding:2px; cursor:pointer;
}
.row{display:grid; grid-template-columns:1fr 1fr; gap:12px}
.field{min-width:0}

.btn-primary, .btn-secondary{
  border:none; border-radius:8px; padding:12px 18px; font-size:0.95rem; font-weight:600;
  cursor:pointer; width:100%;
}
.btn-primary{background:var(--accent); color:var(--accent-text)}
.btn-secondary{background:transparent; border:1px solid var(--border); color:var(--text)}
.btn-secondary:disabled{opacity:0.5; cursor:not-allowed}

.preview-panel{display:flex; flex-direction:column; align-items:center; justify-content:center; text-align:center}
.qr-canvas-wrap{
  background:#fff; border-radius:8px; padding:16px; margin-bottom:16px;
  display:flex; align-items:center; justify-content:center; min-height:200px;
}
.qr-canvas-wrap img, .qr-canvas-wrap canvas{max-width:100%; height:auto}
.download-row{width:100%}
.hint{color:var(--muted); font-size:0.82rem; margin-top:14px; margin-bottom:0}

.faq{margin-top:40px; margin-bottom:40px}
.faq h2{font-size:1.3rem}
.faq details{border:1px solid var(--border); border-radius:8px; padding:12px 16px; margin-bottom:8px; background:var(--panel)}
.faq summary{cursor:pointer; font-weight:600}
.faq p{color:var(--muted); margin-bottom:0}

.ad-slot{
  max-width:880px; margin:24px auto; min-height:1px;
}

.site-footer{border-top:1px solid var(--border); padding-block:20px; margin-top:20px}
.site-footer p{color:var(--muted); font-size:0.85rem; text-align:center; margin:0}
.site-footer a{color:var(--muted)}

img{max-width:100%}