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

:root {
  --bg: #0f1117;
  --surface: #1a1d27;
  --surface2: #22263a;
  --border: #2e3350;
  --accent: #5b8dee;
  --accent-hover: #7aa4f4;
  --danger: #e05c5c;
  --success: #4cba74;
  --warn: #e0a93c;
  --text: #e8eaf0;
  --text-muted: #7a7f9a;
  --msg-local-bg: #243559;
  --msg-remote-bg: #22263a;
  --msg-system-color: #6b7196;
  --radius: 10px;
  --radius-sm: 6px;
}

html, body { height: 100%; font-family: 'Segoe UI', system-ui, sans-serif; background: var(--bg); color: var(--text); }

#app { height: 100%; display: flex; align-items: center; justify-content: center; }

/* ── Login ── */
#login-screen { width: 100%; display: flex; align-items: center; justify-content: center; padding: 24px; }

.login-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 40px 36px;
  width: 100%;
  max-width: 400px;
  box-shadow: 0 8px 32px rgba(0,0,0,.4);
}

.login-card h1 { font-size: 1.7rem; font-weight: 700; margin-bottom: 4px; color: var(--accent); }
.subtitle { color: var(--text-muted); font-size: .9rem; margin-bottom: 28px; }

#join-form label { display: block; font-size: .82rem; font-weight: 600; color: var(--text-muted); text-transform: uppercase; letter-spacing: .05em; margin-bottom: 6px; }
#join-form input {
  width: 100%;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
  color: var(--text);
  font-size: 1rem;
  margin-bottom: 4px;
  transition: border-color .15s;
}
#join-form input:focus { outline: none; border-color: var(--accent); }
#join-form input:invalid:not(:placeholder-shown) { border-color: var(--danger); }
.hint { display: block; font-size: .76rem; color: var(--text-muted); margin-bottom: 18px; }

#join-form button {
  width: 100%;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: var(--radius-sm);
  padding: 11px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background .15s;
  margin-top: 4px;
}
#join-form button:hover { background: var(--accent-hover); }

.form-error { color: var(--danger); font-size: .85rem; margin-top: 10px; text-align: center; }

/* ── Chat ── */
#chat-screen { display: flex; flex-direction: column; height: 100vh; width: 100%; max-width: 700px; }

#chat-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 20px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

#status-bar { display: flex; align-items: center; gap: 8px; font-size: .9rem; }

#status-dot {
  width: 10px; height: 10px;
  border-radius: 50%;
  background: var(--text-muted);
  flex-shrink: 0;
  transition: background .3s;
}

.state-connecting #status-dot { background: var(--warn); }
.state-waiting    #status-dot { background: var(--warn); animation: pulse 1.5s infinite; }
.state-negotiating #status-dot { background: var(--accent); animation: pulse 1s infinite; }
.state-connected  #status-dot { background: var(--success); }
.state-error      #status-dot { background: var(--danger); }

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: .3; }
}

#room-label { font-size: .82rem; color: var(--text-muted); }

#chat-messages {
  flex: 1;
  overflow-y: auto;
  padding: 16px 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

#chat-messages::-webkit-scrollbar { width: 6px; }
#chat-messages::-webkit-scrollbar-track { background: transparent; }
#chat-messages::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }

.message {
  max-width: 72%;
  padding: 8px 14px;
  border-radius: var(--radius);
  font-size: .95rem;
  line-height: 1.4;
  word-break: break-word;
}

.message-local {
  align-self: flex-end;
  background: var(--msg-local-bg);
  color: #c9dbff;
  border-bottom-right-radius: 3px;
}

.message-remote {
  align-self: flex-start;
  background: var(--msg-remote-bg);
  border: 1px solid var(--border);
  border-bottom-left-radius: 3px;
}

.message-sender {
  font-size: .75rem;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 2px;
  opacity: .85;
}

.message-author {
  font-size: .72rem;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 2px;
  letter-spacing: .02em;
}

.message-body { white-space: pre-wrap; word-break: break-word; }

.message-system {
  align-self: center;
  max-width: 90%;
  background: transparent;
  color: var(--msg-system-color);
  font-size: .8rem;
  font-style: italic;
  padding: 2px 8px;
}

#chat-footer {
  display: flex;
  gap: 10px;
  padding: 12px 20px;
  background: var(--surface);
  border-top: 1px solid var(--border);
  flex-shrink: 0;
}

#message-input {
  flex: 1;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
  color: var(--text);
  font-size: .95rem;
  transition: border-color .15s;
}
#message-input:focus { outline: none; border-color: var(--accent); }
#message-input:disabled { opacity: .5; cursor: not-allowed; }

#send-btn {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: var(--radius-sm);
  padding: 10px 22px;
  font-size: .95rem;
  font-weight: 600;
  cursor: pointer;
  transition: background .15s;
  white-space: nowrap;
}
#send-btn:hover:not(:disabled) { background: var(--accent-hover); }
#send-btn:disabled { opacity: .5; cursor: not-allowed; }

@media (max-width: 500px) {
  .login-card { padding: 28px 20px; }
  #chat-header { padding: 10px 14px; }
  #chat-messages { padding: 12px 14px; }
  #chat-footer { padding: 10px 14px; }
}