:root { color-scheme: light; --bg:#f3f4f6; --panel:#fff; --panel-soft:#f8fafc; --text:#111827; --muted:#6b7280; --line:#d8dee8; --accent:#2f6fed; --accent-dark:#1f55c7; --danger:#b42318; --shadow:0 18px 45px rgba(15,23,42,.12); }
* { box-sizing: border-box; }
body { margin:0; min-height:100vh; background:var(--bg); color:var(--text); font-family:Arial,"Microsoft YaHei",sans-serif; }
button,select { font:inherit; }
.app { min-height:100vh; display:grid; grid-template-columns:minmax(0,1fr) 380px; gap:20px; padding:20px; }
.preview-panel { min-width:0; display:grid; place-items:center; padding:20px; border:1px solid var(--line); background:var(--panel); box-shadow:var(--shadow); }
#previewCanvas { width:min(100%,calc(100vh - 80px)); max-width:920px; aspect-ratio:1/1; height:auto; display:block; border:1px solid #e5e7eb; background:linear-gradient(45deg,#eee 25%,transparent 25%),linear-gradient(-45deg,#eee 25%,transparent 25%),linear-gradient(45deg,transparent 75%,#eee 75%),linear-gradient(-45deg,transparent 75%,#eee 75%); background-position:0 0,0 12px,12px -12px,-12px 0; background-size:24px 24px; }
.control-panel { display:flex; flex-direction:column; min-height:0; padding:18px; border:1px solid var(--line); background:var(--panel); box-shadow:var(--shadow); }
.panel-header { padding-bottom:14px; border-bottom:1px solid var(--line); }
.panel-header h1 { margin:0 0 6px; font-size:22px; line-height:1.2; }
.panel-header p { margin:0; min-height:20px; color:var(--muted); font-size:13px; }
.panel-header p.is-error { color:var(--danger); }
.controls { overflow:auto; display:grid; gap:14px; padding:16px 0; }
.control-group { display:grid; gap:8px; padding:12px; border:1px solid var(--line); background:var(--panel-soft); }
.control-group label { font-weight:700; font-size:14px; }
.control-group select { width:100%; height:40px; padding:0 10px; border:1px solid #bfc7d4; background:#fff; color:var(--text); }
.actions { display:grid; grid-template-columns:1fr 1fr; gap:10px; padding-top:14px; border-top:1px solid var(--line); }
.actions button { min-height:42px; border:1px solid var(--accent); background:#fff; color:var(--accent); cursor:pointer; }
.actions button:hover { border-color:var(--accent-dark); color:var(--accent-dark); }
.actions button:last-child { background:var(--accent); color:#fff; }
.actions button:last-child:hover { background:var(--accent-dark); color:#fff; }
@media (max-width:900px) { .app{grid-template-columns:1fr;} .control-panel{min-height:auto;} #previewCanvas{width:min(100%,calc(100vh - 260px)); min-width:260px;} }