:root{--bg:#f8fafc;--card:#fff;--text:#0f172a;--muted:#64748b;--primary:#0ea5e9;--border:#e2e8f0}
.dark{--bg:#0f172a;--card:#1e293b;--text:#f1f5f9;--border:#334155}
*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);font-family:Inter,system-ui,sans-serif}
.forum-header{display:flex;align-items:center;justify-content:space-between;padding:12px 16px;background:var(--card);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:10}
.logo{font-weight:800}
.layout{display:grid;grid-template-columns:240px 1fr;max-width:1200px;margin:0 auto}
.sidebar{padding:16px;border-right:1px solid var(--border)} .sidebar a{display:block;padding:8px 0;color:var(--muted);text-decoration:none}
.feed{padding:16px} .thread-card{background:var(--card);border:1px solid var(--border);border-radius:12px;padding:14px;margin-bottom:12px;cursor:pointer}
.avatar{width:32px;height:32px;border-radius:50%;vertical-align:middle;margin-right:6px}
.meta{font-size:.85rem;color:var(--muted)} .badge.sell{background:#dcfce7;color:#166534;padding:2px 8px;border-radius:20px;font-size:.8rem}
.thumb{width:100%;max-height:240px;object-fit:cover;border-radius:8px;margin-top:8px}
.stats{margin-top:8px;color:var(--muted);font-size:.85rem}
.auth-page{display:grid;place-items:center;min-height:100vh;padding:16px}
.card{background:var(--card);border:1px solid var(--border);border-radius:16px;padding:24px;max-width:420px;width:100%}
.card label{display:block;margin-top:12px;font-weight:600} .card input,textarea,select{width:100%;padding:10px;border:1px solid var(--border);border-radius:8px;background:var(--bg);color:var(--text)}
.btn{padding:10px 16px;border-radius:8px;border:1px solid var(--border);text-decoration:none;display:inline-block} .btn.primary{background:var(--primary);color:#fff;border-color:var(--primary)}
.alert{padding:10px;border-radius:8px;margin:8px 0} .alert.err{background:#fee2e2;color:#991b1b} .alert.ok{background:#dcfce7;color:#166534}
.fab{position:fixed;bottom:80px;right:16px;background:var(--primary);color:#fff;padding:12px 18px;border-radius:999px;text-decoration:none;box-shadow:0 4px 12px rgba(0,0,0,.2)}
.mobile-nav{position:fixed;bottom:0;left:0;right:0;background:var(--card);border-top:1px solid var(--border);display:flex;justify-content:space-around;padding:10px 0}
@media(min-width:768px){.mobile-nav{display:none}.fab{bottom:20px}}
@media(max-width:767px){.layout{grid-template-columns:1fr}.sidebar.desktop{display:none}}
.empty{color:var(--muted);text-align:center;padding:40px 0}