:root {
  --bg: #ffffff;
  --text: #0f1026;
  --muted: #4b5563;
  --panel-bg: #e5e7eb;
  --card-bg: #f8f9fa;
  --border: #d1d5db;
  --accent: #2563eb;
  --link: #2563eb;
}
[data-theme="dark"] {
  --bg: #0f1026;
  --text: #e6e6e9;
  --muted: #9ca3af;
  --panel-bg: #1f2235;
  --card-bg: #15182b;
  --border: #2a2e4f;
  --accent: #60a5fa;
  --link: #60a5fa;
}
*{box-sizing:border-box}
html,body{height:100%}
body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,Inter,Helvetica,Arial,sans-serif;background:var(--bg);color:var(--text);line-height:1.55;transition:background .18s ease,color .18s ease}
a{color:var(--link);text-decoration:none}a:hover{text-decoration:underline}
header{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:12px 20px;border-bottom:1px solid var(--border);background:color-mix(in srgb,var(--card-bg) 92%,transparent);backdrop-filter:blur(6px);position:sticky;top:0;z-index:10}
.brand{display:flex;align-items:center;gap:12px}
.brand-mark{width:36px;height:36px;display:grid;place-items:center}
.brand-name{font-weight:700;letter-spacing:.2px}
.container{max-width:1100px;margin:0 auto;padding:24px}
.grid{display:grid;grid-template-columns:repeat(12,1fr);gap:16px}
.card{grid-column:1/-1;border:1px solid var(--border);background:var(--card-bg);border-radius:12px;overflow:hidden;box-shadow:0 1px 1px rgba(0,0,0,.02)}
.card-header{padding:14px 16px;border-bottom:1px solid var(--border);font-weight:600}
.card-body{padding:16px}
.logogram-panel{background:var(--panel-bg);border:1px solid var(--border);border-radius:12px;padding:18px;display:grid;place-items:center;min-height:420px}
#logogramCanvas{max-width:100%;height:auto;display:block;background:transparent}
.theme-toggle{border:1px solid var(--border);background:transparent;color:var(--text);padding:8px 10px;border-radius:10px;cursor:pointer;font-size:14px}
.theme-toggle:hover{background:color-mix(in srgb,var(--border) 40%,transparent)}
footer{border-top:1px solid var(--border);padding:18px 20px;color:var(--muted);font-size:14px}