:root {
  --bg: #0f1117;
  --card: #1a1d27;
  --card-hover: #222638;
  --accent: #0b5fff;
  --accent-hover: #2970ff;
  --text: #e8edf5;
  --text-muted: #8892a8;
  --border: #2a2e3a;
  --success: #22c55e;
  --danger: #ef4444;
  --warning: #f59e0b;
  --radius: 10px;
  --radius-sm: 6px;
  --shadow: 0 2px 12px rgba(0,0,0,0.25);
  font-family: system-ui,-apple-system,Segoe UI,Roboto,"Helvetica Neue",Arial,sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  background: var(--bg);
  color: var(--text);
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}

/* ── Header ── */
.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 16px;
  background: linear-gradient(135deg, #0b1526 0%, #141e33 100%);
  border-bottom: 1px solid var(--border);
  gap: 12px;
}

.header-left h1 {
  font-size: 18px;
  font-weight: 700;
  background: linear-gradient(90deg, var(--accent), #7c3aed);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 10px;
}

/* ── Auth ── */
.user-area {
  display: flex;
  align-items: center;
  gap: 8px;
}

.avatar {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  border: 2px solid var(--accent);
  object-fit: cover;
}

.user-name {
  font-size: 13px;
  font-weight: 500;
  color: var(--text);
  max-width: 120px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* ── Buttons ── */
.btn {
  background: var(--card);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 13px;
  transition: background 0.15s, border-color 0.15s;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}
.btn:hover { background: var(--card-hover); border-color: var(--accent); }
.btn-primary { background: var(--accent); border-color: var(--accent); color: #fff; font-weight: 600; }
.btn-primary:hover { background: var(--accent-hover); }
.btn-secondary { background: transparent; border-color: var(--border); }
.btn-sm { padding: 4px 10px; font-size: 12px; }

/* ── Status ── */
.status { font-size: 11px; padding: 3px 8px; border-radius: 20px; font-weight: 600; }
.status.online { background: rgba(34,197,94,0.15); color: var(--success); }
.status.offline { background: rgba(239,68,68,0.15); color: var(--danger); }

/* ── Tab Bar ── */
.tab-bar {
  display: flex;
  background: var(--card);
  border-bottom: 1px solid var(--border);
  padding: 0 12px;
  gap: 2px;
  overflow-x: auto;
}

.tab {
  background: none;
  border: none;
  color: var(--text-muted);
  padding: 10px 16px;
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  border-bottom: 2px solid transparent;
  transition: color 0.15s, border-color 0.15s;
  white-space: nowrap;
}

.tab:hover { color: var(--text); }
.tab.active { color: var(--accent); border-bottom-color: var(--accent); }

/* ── Container / Tab Content ── */
.container {
  flex: 1;
  display: flex;
  flex-direction: column;
  max-width: 960px;
  margin: 0 auto;
  padding: 12px;
  width: 100%;
}

.tab-content { display: none; flex-direction: column; flex: 1; }
.tab-content.active { display: flex; }

.tab-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 10px;
  flex-wrap: wrap;
}

.tab-header h2 {
  font-size: 16px;
  font-weight: 600;
}

.tab-hint {
  font-size: 12px;
  color: var(--text-muted);
}

/* ── Messages ── */
.messages {
  flex: 1;
  min-height: 200px;
  max-height: calc(100dvh - 280px);
  background: var(--card);
  border-radius: var(--radius);
  padding: 12px;
  border: 1px solid var(--border);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.messages-placeholder {
  color: var(--text-muted);
  text-align: center;
  padding: 40px 16px;
  font-size: 14px;
}

.message {
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  background: var(--bg);
  max-width: 85%;
  animation: msgIn 0.2s ease;
}

@keyframes msgIn {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

.message.own {
  align-self: flex-end;
  background: linear-gradient(135deg, #0b1f4a, #162a5c);
  border: 1px solid var(--accent);
}

.message.other {
  align-self: flex-start;
  background: var(--bg);
  border: 1px solid var(--border);
}

.message.system {
  align-self: center;
  background: rgba(245,158,11,0.1);
  border: 1px solid rgba(245,158,11,0.3);
  color: var(--warning);
  font-size: 12px;
  text-align: center;
  max-width: 90%;
}

.message .who {
  font-size: 11px;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 2px;
}

.message.own .who { color: var(--success); }

.message .text {
  font-size: 14px;
  line-height: 1.45;
  word-break: break-word;
}

.message .time {
  font-size: 10px;
  color: var(--text-muted);
  margin-top: 4px;
  text-align: right;
}

/* ── Send Form ── */
.send-form {
  display: flex;
  gap: 8px;
  margin-top: 8px;
}

.send-form input[type="text"] {
  flex: 1;
  padding: 10px 14px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text);
  font-size: 14px;
  outline: none;
  transition: border-color 0.15s;
}
.send-form input[type="text"]:focus { border-color: var(--accent); }
.send-form input[type="text"]::placeholder { color: var(--text-muted); }

/* ── P2P Layout ── */
.p2p-layout {
  display: flex;
  gap: 12px;
  flex: 1;
  min-height: 0;
}

.p2p-sidebar {
  width: 200px;
  flex-shrink: 0;
  background: var(--card);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
}

.sidebar-header h3 { font-size: 13px; font-weight: 600; }

.peer-list {
  flex: 1;
  overflow-y: auto;
  padding: 4px;
}

.peer-list-placeholder {
  color: var(--text-muted);
  font-size: 12px;
  text-align: center;
  padding: 20px 8px;
}

.peer-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background 0.15s;
  font-size: 13px;
}

.peer-item:hover { background: var(--card-hover); }
.peer-item.active { background: rgba(11,95,255,0.15); border: 1px solid var(--accent); }
.peer-item .peer-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--success); flex-shrink: 0; }
.peer-item .peer-name { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

.p2p-chat {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.connection-status {
  font-size: 12px;
  color: var(--text-muted);
}
.connection-status.connected { color: var(--success); }
.connection-status.connecting { color: var(--warning); }
.connection-status.disconnected { color: var(--danger); }

/* ── Scrollbar ── */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }

/* ── Responsive ── */
@media (max-width: 700px) {
  .p2p-layout { flex-direction: column; }
  .p2p-sidebar { width: 100%; max-height: 140px; }
  .user-name { max-width: 80px; }
  .container { padding: 8px; }
  .messages { max-height: calc(100dvh - 360px); }
}

@media (max-width: 480px) {
  .app-header { padding: 8px 10px; }
  .header-left h1 { font-size: 15px; }
  .tab { padding: 8px 12px; font-size: 12px; }
}