* { margin:0; padding:0; box-sizing:border-box; }
body { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; background:#f0f2f5; height:100vh; }

#auth-area { display:flex; justify-content:center; align-items:center; height:100vh; }
.auth-box { background:#fff; padding:30px; border-radius:8px; box-shadow:0 0 10px rgba(0,0,0,0.1); width:320px; }
.auth-box input { width:100%; padding:10px; margin:6px 0; border:1px solid #ddd; border-radius:4px; }
.auth-box button { width:100%; padding:10px; margin-top:10px; background:#4a90e2; color:#fff; border:none; border-radius:4px; cursor:pointer; font-size:16px; }
.auth-box button:hover { background:#357abd; }
.auth-box hr { margin:20px 0; }

#chat-area { display:flex; height:100vh; }
.sidebar { width:260px; background:#2c3e50; color:#ecf0f1; display:flex; flex-direction:column; }
.sidebar-header { padding:15px; background:#1a252f; display:flex; justify-content:space-between; align-items:center; }
.sidebar-header h3 { font-size:18px; }
.sidebar-header button { background:none; border:none; color:#ecf0f1; font-size:20px; cursor:pointer; }
.sidebar-tabs { display:flex; border-bottom:1px solid #1a252f; }
.sidebar-tabs button { flex:1; padding:12px; background:#2c3e50; color:#ecf0f1; border:none; cursor:pointer; transition:0.2s; }
.sidebar-tabs button.active, .sidebar-tabs button:hover { background:#1a252f; }
#sidebar-content { flex:1; overflow-y:auto; }
.create-group { padding:10px; border-bottom:1px solid #1a252f; }
.create-group input { width:100%; padding:6px; margin-bottom:5px; border:1px solid #1a252f; border-radius:4px; background:#34495e; color:#fff; }
.create-group button { width:100%; padding:6px; background:#27ae60; color:#fff; border:none; border-radius:4px; cursor:pointer; }
.contact-item { padding:12px 15px; cursor:pointer; transition:0.2s; border-bottom:1px solid #1a252f; }
.contact-item:hover { background:#34495e; }
.request-item { padding:10px 15px; border-bottom:1px solid #1a252f; display:flex; justify-content:space-between; align-items:center; }
.request-actions button { margin-left:5px; padding:4px 8px; border:none; border-radius:4px; cursor:pointer; }
.accept-btn { background:#27ae60; color:#fff; }
.reject-btn { background:#e74c3c; color:#fff; }
.empty-hint { padding:20px; text-align:center; color:#95a5a6; }

.chat-main { flex:1; display:flex; flex-direction:column; }
#chat-header { padding:15px; background:#fff; border-bottom:1px solid #ddd; font-weight:bold; font-size:18px; }
#messages { flex:1; padding:20px; overflow-y:auto; background:#f9f9f9; }
.message { margin-bottom:12px; background:#fff; padding:10px; border-radius:6px; box-shadow:0 1px 2px rgba(0,0,0,0.05); }
.message .sender { font-weight:bold; margin-right:8px; }
.message .time { font-size:12px; color:#888; margin-left:10px; }
.msg-actions { margin-top:5px; }
.msg-actions button { background:none; border:none; color:#888; font-size:12px; cursor:pointer; margin-right:10px; }
.msg-actions button:hover { color:#333; }

.chat-input { display:flex; padding:15px; background:#fff; border-top:1px solid #ddd; }
.chat-input textarea { flex:1; padding:10px; border:1px solid #ddd; border-radius:4px; resize:none; height:50px; }
.chat-input button { margin-left:10px; padding:0 20px; background:#4a90e2; color:#fff; border:none; border-radius:4px; font-size:16px; cursor:pointer; }
.chat-input button:hover { background:#357abd; }