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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.container {
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    width: 100%;
    max-width: 500px;
    overflow: hidden;
}

.login-section {
    padding: 40px;
}

.login-section h1 {
    text-align: center;
    color: #333;
    margin-bottom: 30px;
    font-size: 28px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: #555;
    font-weight: 500;
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid #e0e0e0;
    border-radius: 10px;
    font-size: 16px;
    transition: border-color 0.3s;
}

.form-group input:focus,
.form-group select:focus {
    outline: none;
    border-color: #667eea;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 10px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    width: 100%;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.btn-secondary {
    background: #f0f0f0;
    color: #333;
}

.btn-secondary:hover {
    background: #e0e0e0;
}

.btn-success {
    background: #10b981;
    color: white;
}

.btn-success:hover {
    background: #059669;
}

.btn-danger {
    background: #ef4444;
    color: white;
}

.btn-danger:hover {
    background: #dc2626;
}

.btn-control {
    background: #3b82f6;
    color: white;
}

.btn-control:hover {
    background: #2563eb;
}

.call-section {
    padding: 20px;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 20px;
    border-bottom: 2px solid #f0f0f0;
}

.header h2 {
    color: #333;
    font-size: 24px;
}

.user-list-container {
    margin-bottom: 20px;
}

.user-list-container h3 {
    color: #555;
    margin-bottom: 15px;
    font-size: 18px;
}

.user-list {
    max-height: 300px;
    overflow-y: auto;
    border: 2px solid #f0f0f0;
    border-radius: 10px;
}

.user-item {
    padding: 15px;
    border-bottom: 1px solid #f0f0f0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background 0.3s;
}

.user-item:last-child {
    border-bottom: none;
}

.user-item:hover {
    background: #f8f9fa;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 10px;
}

.user-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
    font-size: 16px;
}

.user-details h4 {
    color: #333;
    font-size: 16px;
    margin-bottom: 2px;
}

.user-details p {
    color: #888;
    font-size: 14px;
}

.call-btn {
    background: #10b981;
    color: white;
    padding: 8px 16px;
    font-size: 14px;
}

.call-btn:hover {
    background: #059669;
}

.call-controls {
    text-align: center;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 10px;
}

.call-status {
    font-size: 20px;
    font-weight: 600;
    color: #10b981;
    margin-bottom: 10px;
}

.call-timer {
    font-size: 32px;
    font-weight: bold;
    color: #333;
    margin-bottom: 20px;
    font-family: 'Courier New', monospace;
}

.call-buttons {
    display: flex;
    justify-content: center;
    gap: 15px;
    flex-wrap: wrap;
}

.incoming-call {
    text-align: center;
    padding: 30px;
    background: #f0f9ff;
    border: 2px solid #3b82f6;
    border-radius: 10px;
}

.incoming-call h3 {
    color: #3b82f6;
    margin-bottom: 15px;
    font-size: 22px;
}

.incoming-call p {
    color: #555;
    margin-bottom: 20px;
    font-size: 16px;
}

::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #f1f1f1;
    border-radius: 10px;
}

::-webkit-scrollbar-thumb {
    background: #888;
    border-radius: 10px;
}

::-webkit-scrollbar-thumb:hover {
    background: #555;
}

@media (max-width: 480px) {
    .container {
        border-radius: 0;
        min-height: 100vh;
    }

    .login-section {
        padding: 30px 20px;
    }

    .call-section {
        padding: 15px;
    }

    .call-buttons {
        flex-direction: column;
    }

    .call-buttons .btn {
        width: 100%;
        justify-content: center;
    }
}