body { font-family: system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif; margin: 0; background:#0b1220; color:#e9eef8; }
header { display:flex; justify-content:space-between; align-items:center; padding: 10px 16px; background:#0e1730; border-bottom:1px solid #1e2a55;}
h1 { margin:0; font-size:20px; }
nav a { color:#b8c6ff; margin-left:10px; text-decoration:none; }
main { max-width: 900px; margin: 30px auto; padding: 0 16px; }
.card { background:#0f1b3a; border:1px solid #223066; border-radius:12px; padding:16px; box-shadow: 0 6px 18px rgba(0,0,0,0.2); }
.btn { background:#3a5fff; color:white; padding:10px 14px; border-radius:8px; border:none; text-decoration:none; cursor:pointer; }
.btn:hover { background:#2e4de0; }
.pre-box { background:#0a1430; border:1px solid #1f2a55; border-radius:8px; padding:12px; white-space:pre-wrap; }