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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f5f5f5;
    color: #333;
    line-height: 1.6;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    margin-bottom: 30px;
}

h1 {
    color: #2c3e50;
    font-size: 2.5em;
    margin-bottom: 10px;
}

.section {
    background: white;
    margin-bottom: 20px;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

h2 {
    color: #34495e;
    margin-bottom: 15px;
    border-bottom: 2px solid #3498db;
    padding-bottom: 5px;
}

.form-group {
    margin-bottom: 15px;
}

.form-group small {
    display: block;
    margin-top: 4px;
    color: #666;
    font-size: 0.9em;
    font-style: italic;
}

label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
    color: #2c3e50;
}

input[type="text"],
input[type="password"],
input[type="number"],
textarea {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 14px;
    transition: border-color 0.3s;
}

input[type="text"]:focus,
input[type="password"]:focus,
input[type="number"]:focus,
textarea:focus {
    outline: none;
    border-color: #3498db;
    box-shadow: 0 0 5px rgba(52, 152, 219, 0.3);
}

button {
    background-color: #3498db;
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    margin-right: 10px;
    margin-bottom: 10px;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #2980b9;
}

button:disabled {
    background-color: #bdc3c7;
    cursor: not-allowed;
}

button#register-btn {
    background-color: #27ae60;
}

button#register-btn:hover {
    background-color: #229954;
}

button#unregister-btn {
    background-color: #e74c3c;
}

button#unregister-btn:hover {
    background-color: #c0392b;
}

button#call-btn {
    background-color: #27ae60;
}

button#call-btn:hover {
    background-color: #229954;
}

button#answer-btn {
    background-color: #27ae60;
}

button#answer-btn:hover {
    background-color: #229954;
}

button#hangup-btn {
    background-color: #e74c3c;
}

button#hangup-btn:hover {
    background-color: #c0392b;
}

button#hold-btn,
button#transfer-btn {
    background-color: #f39c12;
}

button#hold-btn:hover,
button#transfer-btn:hover {
    background-color: #e67e22;
}

.call-controls {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 15px;
}

.status {
    margin-top: 15px;
    padding: 10px;
    border-radius: 4px;
    font-weight: bold;
}

.status.success {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.status.error {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.status.info {
    background-color: #d1ecf1;
    color: #0c5460;
    border: 1px solid #bee5eb;
}

.messages,
.voicemail {
    margin-top: 15px;
    max-height: 300px;
    overflow-y: auto;
    border: 1px solid #ddd;
    border-radius: 4px;
    padding: 10px;
}

.message-item,
.voicemail-item {
    padding: 10px;
    margin-bottom: 10px;
    border-radius: 4px;
    background-color: #f8f9fa;
    border-left: 4px solid #3498db;
}

.message-item.sent {
    background-color: #e8f5e8;
    border-left-color: #27ae60;
}

.message-item.received {
    background-color: #e8f4fd;
    border-left-color: #3498db;
}

.message-meta {
    font-size: 12px;
    color: #666;
    margin-bottom: 5px;
}

.message-content {
    font-size: 14px;
}

.logs {
    margin-top: 15px;
    max-height: 400px;
    overflow-y: auto;
    border: 1px solid #ddd;
    border-radius: 4px;
    padding: 10px;
    background-color: #f8f9fa;
    font-family: monospace;
    font-size: 12px;
}

.log-entry {
    margin-bottom: 5px;
    padding: 3px 5px;
    border-radius: 2px;
}

.log-entry.debug {
    color: #6c757d;
    background-color: #f8f9fa;
}

.log-entry.info {
    color: #0c5460;
    background-color: #d1ecf1;
}

.log-entry.warn {
    color: #856404;
    background-color: #fff3cd;
}

.log-entry.error {
    color: #721c24;
    background-color: #f8d7da;
}

.log-entry.success {
    color: #155724;
    background-color: #d4edda;
}

.log-timestamp {
    font-weight: bold;
    margin-right: 8px;
}

.log-level {
    font-weight: bold;
    margin-right: 8px;
    text-transform: uppercase;
}

@media (max-width: 600px) {
    .container {
        padding: 10px;
    }
    
    .call-controls {
        flex-direction: column;
    }
    
    button {
        width: 100%;
        margin-right: 0;
    }
}