:root {
  --color-primary: #1a56db;
  --color-primary-dark: #143fa0;
  --color-bg: #f3f4f6;
  --color-surface: #ffffff;
  --color-text: #1f2937;
  --color-text-secondary: #6b7280;
  --color-border: #e5e7eb;
  --color-success: #059669;
  --color-danger: #dc2626;
  --color-warning: #d97706;
  --color-me: #e8f0fe;
  --color-peer: #f9fafb;
  --color-system: #fef3c7;
  --font-sans: 'Noto Sans SC', 'Source Han Sans CN', 'WenQuanYi Micro Hei', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --radius: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.1), 0 4px 6px rgba(0,0,0,0.05);
}

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

body {
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  height: 100vh;
  overflow: hidden;
  font-size: 14px;
  line-height: 1.6;
}

button { font-family: inherit; cursor: pointer; border: none; outline: none; }
input { font-family: inherit; outline: none; }
ul { list-style: none; }
a { color: var(--color-primary); text-decoration: none; }

/* ========== Modal ========== */
.modal-overlay {
  position: fixed; inset: 0;
  background: rgba(0,0,0,0.5);
  display: flex; align-items: center; justify-content: center;
  z-index: 1000;
  padding: 20px;
}
.modal-box {
  background: var(--color-surface);
  border-radius: var(--radius);
  max-width: 640px; width: 100%;
  max-height: 85vh; overflow-y: auto;
  padding: 32px;
  box-shadow: var(--shadow-lg);
}
.modal-box h2 {
  font-size: 20px; font-weight: 700;
  margin-bottom: 20px;
  color: var(--color-primary-dark);
  border-bottom: 2px solid var(--color-primary);
  padding-bottom: 12px;
}
.modal-box h3 {
  font-size: 15px; font-weight: 600;
  margin: 16px 0 8px;
  color: var(--color-text);
}
.modal-body p, .modal-body li {
  font-size: 13px;
  color: var(--color-text-secondary);
  margin-bottom: 6px;
}
.modal-body ul { padding-left: 20px; }
.modal-body li { list-style: disc; }
.modal-body strong { color: var(--color-text); font-weight: 600; }
.btn-primary {
  display: block; width: 100%;
  margin-top: 24px;
  padding: 12px 20px;
  background: var(--color-primary);
  color: #fff;
  font-size: 15px; font-weight: 600;
  border-radius: var(--radius);
  transition: background 0.2s;
}
.btn-primary:hover { background: var(--color-primary-dark); }
.btn-primary:disabled { background: #9ca3af; cursor: not-allowed; }

/* ========== Login ========== */
.login-panel {
  display: flex; align-items: center; justify-content: center;
  height: 100vh;
  background: linear-gradient(135deg, #1e3a5f 0%, #1a56db 50%, #3b82f6 100%);
}
.login-card {
  background: var(--color-surface);
  border-radius: 12px;
  padding: 40px;
  width: 100%; max-width: 420px;
  box-shadow: var(--shadow-lg);
}
.login-title {
  font-size: 28px; font-weight: 800;
  color: var(--color-primary-dark);
  text-align: center;
  margin-bottom: 4px;
}
.login-subtitle {
  font-size: 13px;
  color: var(--color-text-secondary);
  text-align: center;
  margin-bottom: 28px;
}
.form-group { margin-bottom: 18px; }
.form-group label {
  display: block;
  font-size: 13px; font-weight: 600;
  color: var(--color-text);
  margin-bottom: 6px;
}
.form-group input {
  width: 100%;
  padding: 11px 14px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-size: 14px;
  transition: border-color 0.2s, box-shadow 0.2s;
}
.form-group input:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(26,86,219,0.1);
}
.login-actions {
  display: flex; gap: 12px;
  margin-top: 24px;
}
.btn-secondary {
  flex: 1;
  padding: 12px 20px;
  background: #fff;
  color: var(--color-primary);
  font-size: 14px; font-weight: 600;
  border: 1.5px solid var(--color-primary);
  border-radius: var(--radius);
  transition: background 0.2s;
}
.btn-secondary:hover { background: #eff6ff; }
.login-hint {
  font-size: 12px;
  color: var(--color-text-secondary);
  text-align: center;
  margin-top: 20px;
  line-height: 1.6;
}

/* ========== Chat ========== */
.chat-panel {
  display: flex; flex-direction: column;
  height: 100vh;
}
.chat-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 20px;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  box-shadow: 0 1px 2px rgba(0,0,0,0.04);
}
.chat-header-left { display: flex; align-items: center; gap: 12px; }
.room-title {
  font-size: 16px; font-weight: 700;
  color: var(--color-text);
}
.conn-info {
  font-size: 12px;
  color: var(--color-text-secondary);
  padding: 2px 8px;
  background: #f3f4f6;
  border-radius: 4px;
}
.chat-header-right { display: flex; align-items: center; gap: 8px; }
.status-dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: #9ca3af;
  display: inline-block;
}
.status-dot.connected { background: var(--color-success); box-shadow: 0 0 4px var(--color-success); }
.status-dot.connecting, .status-dot.reconnecting { background: var(--color-warning); animation: pulse 1s infinite; }
.status-dot.failed { background: var(--color-danger); }
.status-dot.closed { background: #9ca3af; }
@keyframes pulse { 0%,100%{opacity:1} 50%{opacity:0.4} }
.status-text { font-size: 12px; color: var(--color-text-secondary); }
.btn-icon {
  padding: 6px 12px;
  background: #f3f4f6;
  color: var(--color-text-secondary);
  font-size: 12px;
  border-radius: 4px;
  transition: background 0.2s;
}
.btn-icon:hover { background: #e5e7eb; }

.chat-main {
  flex: 1;
  display: flex; flex-direction: column;
  overflow: hidden;
  background: var(--color-bg);
}
.messages {
  flex: 1;
  overflow-y: auto;
  padding: 20px;
  display: flex; flex-direction: column; gap: 12px;
}
.msg {
  max-width: 70%;
  padding: 10px 14px;
  border-radius: 10px;
  word-wrap: break-word;
}
.msg-me {
  align-self: flex-end;
  background: var(--color-me);
  border-bottom-right-radius: 4px;
}
.msg-peer {
  align-self: flex-start;
  background: var(--color-peer);
  border: 1px solid var(--color-border);
  border-bottom-left-radius: 4px;
}
.msg-system {
  align-self: center;
  background: var(--color-system);
  font-size: 12px;
  color: #92400e;
  padding: 6px 14px;
  border-radius: 20px;
  max-width: 90%;
}
.msg-header {
  display: flex; align-items: center; gap: 8px;
  margin-bottom: 4px;
}
.msg-name {
  font-size: 12px; font-weight: 600;
  color: var(--color-text-secondary);
}
.msg-verify {
  font-size: 11px;
  padding: 1px 6px;
  border-radius: 3px;
}
.verify-ok { background: #d1fae5; color: var(--color-success); }
.verify-fail { background: #fee2e2; color: var(--color-danger); }
.msg-body { font-size: 14px; white-space: pre-wrap; }
.file-msg { display: flex; align-items: center; gap: 6px; }
.file-icon { font-size: 16px; }
.file-size { color: var(--color-text-secondary); font-size: 12px; }
.file-download { font-size: 12px; margin-left: 6px; }

.debug-panel {
  background: #1e293b;
  color: #e2e8f0;
  font-family: 'JetBrains Mono', 'Fira Code', monospace;
  font-size: 11px;
  padding: 12px 16px;
  max-height: 180px;
  overflow-y: auto;
  white-space: pre-wrap;
  border-top: 1px solid #334155;
}

/* ========== Sidebar ========== */
.chat-sidebar {
  position: fixed;
  right: 0; top: 0;
  width: 220px; height: 100vh;
  background: var(--color-surface);
  border-left: 1px solid var(--color-border);
  padding: 60px 16px 16px;
  display: flex; flex-direction: column;
  gap: 12px;
}
.chat-sidebar h3 {
  font-size: 13px; font-weight: 600;
  color: var(--color-text);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.members-list { flex: 1; overflow-y: auto; }
.member-item {
  display: flex; align-items: center; gap: 8px;
  padding: 8px 0;
  border-bottom: 1px solid #f3f4f6;
}
.member-dot {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--color-success);
}
.member-name { font-size: 13px; flex: 1; }
.member-role {
  font-size: 11px;
  color: var(--color-primary);
  background: #eff6ff;
  padding: 1px 6px;
  border-radius: 3px;
}
.sidebar-info {
  font-size: 11px;
  color: var(--color-text-secondary);
  padding: 12px;
  background: #f9fafb;
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
}
.sidebar-info p { margin-bottom: 4px; }

/* ========== Footer ========== */
.chat-footer {
  display: flex; align-items: center; gap: 10px;
  padding: 12px 20px;
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding-right: 240px;
}
.chat-footer #msg-input {
  flex: 1;
  padding: 11px 14px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-size: 14px;
}
.chat-footer #msg-input:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(26,86,219,0.1);
}
.chat-footer .btn-primary {
  width: auto;
  margin: 0;
  padding: 11px 24px;
}

/* ========== Responsive ========== */
@media (max-width: 768px) {
  .chat-sidebar { display: none; }
  .chat-footer { padding-right: 20px; }
  .msg { max-width: 85%; }
}