:root {
    --primary-color: #007bff;
    --secondary-color: #6c757d;
    --background-color: #f8f9fa;
    --text-color: #333;
    --card-background: #ffffff;
    --border-color: #dee2e6;
    --success-color: #28a745;
    --error-color: #dc3545;
    --connecting-color: #ffc107;
}

body {
    font-family: 'Roboto', sans-serif;
    margin: 0;
    padding: 20px;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
}

.container {
    max-width: 700px;
    margin: 0 auto;
    padding: 20px;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 1rem;
}

h1 {
    color: var(--primary-color);
    margin: 0;
}

.connection-status {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 500;
}

.status-dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background-color: var(--secondary-color);
    transition: background-color 0.3s;
}

.status-dot.connected { background-color: var(--success-color); }
.status-dot.connecting { background-color: var(--connecting-color); }
.status-dot.disconnected { background-color: var(--error-color); }


.main-content {
    text-align: center;
    margin-bottom: 2rem;
}

.button-primary, .button-secondary {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s;
}

.button-primary {
    background-color: var(--primary-color);
    color: white;
}
.button-primary:hover {
    background-color: #0056b3;
}

.button-secondary {
    background-color: var(--secondary-color);
    color: white;
}
.button-secondary:hover {
    background-color: #5a6268;
}

.config-section {
    display: grid;
    gap: 1.5rem;
}

.card {
    background-color: var(--card-background);
    border-radius: 12px;
    padding: 25px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

.card h2 {
    margin-top: 0;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

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

select, input[type="number"] {
    width: 100%;
    padding: 10px;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    font-size: 16px;
}

.slider-container {
    display: flex;
    align-items: center;
    gap: 15px;
}

input[type="range"] {
    flex-grow: 1;
}

.progress-bar {
    width: 100%;
    background-color: #e9ecef;
    border-radius: 6px;
    margin-top: 10px;
    overflow: hidden;
    position: relative;
    height: 25px;
}
.progress-bar .progress {
    width: 0%;
    height: 100%;
    background-color: var(--success-color);
    transition: width 0.2s;
}
.progress-bar span {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: #333;
    font-weight: 500;
}


.footer-actions {
    margin-top: 1.5rem;
    text-align: center;
}

.send-status {
    margin-left: 1rem;
    font-weight: 500;
    color: var(--success-color);
}

.error-message {
    color: var(--error-color);
    font-weight: 500;
}