*{box-sizing:border-box;font-family:Arial,Helvetica,sans-serif}
body{margin:0;background:#f4f4f6;color:#222}
.site-header{background:#1b3a4b;color:#fff;padding:12px 16px;display:flex;align-items:center;justify-content:space-between}
.site-header nav a{color:#fff;margin-left:12px;text-decoration:none}
main{padding:16px}
.hero{background:#fff;padding:16px;border-radius:6px;margin-bottom:12px}
.forum-columns{display:flex;gap:16px}
.categories{width:220px;background:#fff;padding:12px;border-radius:6px}
.threads{flex:1;background:#fff;padding:12px;border-radius:6px}
button{background:#1b3a4b;color:#fff;border:none;padding:8px 12px;border-radius:4px;cursor:pointer}
form label{display:block;margin-bottom:8px}
input[type="text"]{width:100%;padding:8px;border:1px solid #ddd;border-radius:4px}