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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}

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

.header h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

.header p {
    font-size: 1.1em;
    opacity: 0.9;
}

.test-panels {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 20px;
    margin-bottom: 20px;
}

.panel {
    background: white;
    border-radius: 15px;
    padding: 25px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.3);
    transition: transform 0.3s ease;
}

.panel:hover {
    transform: translateY(-5px);
}

.panel h2 {
    color: #667eea;
    margin-bottom: 20px;
    font-size: 1.5em;
    border-bottom: 3px solid #667eea;
    padding-bottom: 10px;
}

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

.form-group label {
    display: block;
    margin-bottom: 5px;
    color: #333;
    font-weight: 600;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 10px;
    border: 2px solid #ddd;
    border-radius: 8px;
    font-size: 14px;
    transition: border-color 0.3s;
}

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

.btn {
    width: 100%;
    padding: 12px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    margin-top: 10px;
}

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

.btn-primary:hover {
    transform: scale(1.02);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.btn-danger {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    color: white;
}

.btn-danger:hover {
    transform: scale(1.02);
    box-shadow: 0 5px 15px rgba(245, 87, 108, 0.4);
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none !important;
}

.output {
    margin-top: 15px;
    padding: 15px;
    background: #f8f9fa;
    border-radius: 8px;
    border-left: 4px solid #667eea;
    max-height: 300px;
    overflow-y: auto;
    font-family: 'Courier New', monospace;
    font-size: 13px;
    line-height: 1.6;
}

.output .message {
    padding: 5px 0;
    border-bottom: 1px solid #e0e0e0;
}

.output .message:last-child {
    border-bottom: none;
}

.output .timestamp {
    color: #999;
    font-size: 11px;
}

.output .sent {
    color: #2196F3;
}

.output .received {
    color: #4CAF50;
}

.output .error {
    color: #f44336;
}

.output .info {
    color: #FF9800;
}

.status {
    display: inline-block;
    padding: 5px 15px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    margin-bottom: 10px;
}

.status.connected {
    background: #4CAF50;
    color: white;
}

.status.disconnected {
    background: #f44336;
    color: white;
}

.status.connecting {
    background: #FF9800;
    color: white;
}

.progress-bar {
    width: 100%;
    height: 30px;
    background: #e0e0e0;
    border-radius: 15px;
    overflow: hidden;
    margin-top: 10px;
    display: none;
}

.progress-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, #667eea 0%, #764ba2 100%);
    transition: width 0.3s;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 600;
    font-size: 14px;
}

.file-info {
    margin-top: 10px;
    padding: 10px;
    background: #e3f2fd;
    border-radius: 5px;
    font-size: 13px;
    display: none;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.loading {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 3px solid rgba(255,255,255,.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 1s ease-in-out infinite;
    margin-left: 10px;
}

.backend-info {
    background: rgba(255,255,255,0.2);
    color: white;
    padding: 15px;
    border-radius: 10px;
    text-align: center;
    margin-bottom: 20px;
}