* {
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: #1a1a2e;
    color: #eee;
    margin: 0;
    padding: 20px;
    min-height: 100vh;
}

.container {
    max-width: 500px;
    margin: 0 auto;
}

h1 {
    text-align: center;
    margin-bottom: 30px;
    color: #fff;
}

.status {
    text-align: center;
    padding: 15px;
    border-radius: 8px;
    font-size: 18px;
    font-weight: bold;
    margin-bottom: 20px;
}

.status.disconnected {
    background: #444;
}

.status.connecting {
    background: #f39c12;
    color: #000;
}

.status.registered {
    background: #27ae60;
}

.status.ringing {
    background: #3498db;
    animation: pulse 1s infinite;
}

.status.incall {
    background: #2ecc71;
}

.status.error {
    background: #e74c3c;
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

.controls {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

button {
    flex: 1;
    padding: 15px;
    font-size: 16px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
    font-weight: bold;
}

button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

#registerBtn {
    background: #3498db;
    color: white;
}

#answerBtn {
    background: #27ae60;
    color: white;
}

#hangupBtn {
    background: #e74c3c;
    color: white;
}

button:hover:not(:disabled) {
    transform: scale(1.02);
    filter: brightness(1.1);
}

.info {
    background: #16213e;
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 20px;
}

.info p {
    margin: 5px 0;
    font-family: monospace;
}

.volume-control {
    background: #16213e;
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 15px;
}

.volume-control label {
    white-space: nowrap;
    min-width: 120px;
}

.volume-control input[type="range"] {
    flex: 1;
    height: 8px;
    -webkit-appearance: none;
    background: #333;
    border-radius: 4px;
    outline: none;
}

.volume-control input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 20px;
    height: 20px;
    background: #3498db;
    border-radius: 50%;
    cursor: pointer;
}

.log {
    background: #0f0f23;
    padding: 15px;
    border-radius: 8px;
    height: 250px;
    overflow-y: auto;
    font-family: monospace;
    font-size: 12px;
    line-height: 1.6;
    border: 1px solid #333;
}