:root{--max-width:1100px;--accent:#0b6;--muted:#666}
*{box-sizing:border-box}
body{font-family:system-ui,-apple-system,Segoe UI,Roboto,Arial;margin:0;color:#222;background:#f7f7f8}
.container{max-width:var(--max-width);margin:0 auto;padding:16px}
.site-header{background:#fff;padding:12px 0;border-bottom:1px solid #eee}
.site-header .container{display:flex;align-items:center;justify-content:space-between}
.brand{font-weight:700;text-decoration:none;color:#111}
.site-header nav a{margin-left:12px;text-decoration:none;color:#333;font-size:0.95rem}
.grid{display:flex;flex-direction:column;gap:16px;margin-top:16px}
.sidebar{background:#fff;padding:12px;border-radius:8px;border:1px solid #eee}
.main{flex:1}
.topic, .topic-full, .reply{background:#fff;padding:12px;border:1px solid #eee;border-radius:8px;margin-bottom:12px}
h1,h2,h3{margin:0 0 8px}
label{display:block;margin-bottom:8px}
input,textarea,select{width:100%;padding:8px;border:1px solid #ddd;border-radius:6px;font-size:1rem}
button{background:var(--accent);border:0;color:#fff;padding:10px 14px;border-radius:8px;cursor:pointer}
.error{background:#ffe6e6;color:#900;padding:8px;border-radius:6px;margin-bottom:12px}
.form-row{display:flex;gap:8px}
.form-row > *{flex:1}
img.topic-img{max-width:100%;height:auto;border-radius:6px;margin-top:8px}
.tags{margin-top:8px}
.tag{display:inline-block;padding:4px 8px;background:#eef;border-radius:999px;margin-right:6px;font-size:0.85rem}
@media(min-width:900px){.grid{flex-direction:row}.sidebar{width:260px;flex-shrink:0}}