body { font-family: sans-serif; background: #f5f7fa; margin:0; padding:0; }
#app { max-width: 600px; margin: auto; }
.group { background: #fff; margin: 1em 0; border-radius: 8px; padding: 1em; box-shadow: 0 1px 4px #0002; }
.group-header { display: flex; justify-content: space-between; align-items: center; }
.ptt-btn { padding: 1em; background: #2e7d32; color: #fff; border: none; border-radius: 5px; width: 100%; margin-top: 1em; font-size: 1.1em; }
.ptt-btn:active { background: #1b5e20; }
.close-btn { background: #e53935; color: #fff; border: none; border-radius: 5px; padding: 0.3em 1em; }
.speaker-info { font-size: 0.95em; color: #2e7d32; }