:root {
    --bg-color: #10d3d3;
    --container-bg: rgba(255, 255, 255, 0.95);
    --text-color: #333;
    --text-color-light: #555;
    --border-color: #ccc;
    --hr-color: #ddd;
    --gauge-dial-fill: #e0e0e0;
    --gauge-dial-stroke: #c0c0c0;
    --color-success: #28a745;
    --color-danger: #dc3545;
}

body.dark-mode {
    --bg-color: #121212;
    --container-bg: #1e1e1e;
    --text-color: #e0e0e0;
    --text-color-light: #aaa;
    --border-color: #444;
    --hr-color: #333;
    --gauge-dial-fill: #444;
    --gauge-dial-stroke: #555;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 1rem;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s ease, color 0.3s ease;
}

.top-bar {
    width: 100%;
    max-width: 800px;
    display: flex;
    justify-content: flex-end;
    margin-bottom: -10px; /* Pull button closer to container */
    padding-right: 1rem;
    position: relative; /* Added for z-index context */
    z-index: 10; /* Ensures the button is on top */
}

#darkModeToggle {
    background: none;
    border: 1px var(--border-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    font-size: 1.2rem;
    cursor: pointer;
    color: var(--text-color);
}

.container {
    background: var(--container-bg);
    padding: 1.5rem 2rem;
    border-radius: 12px;
    box-shadow: 0 6px 12px rgba(0,0,0,0.15);
    text-align: center;
    width: 100%;
    max-width: 800px;
    margin-bottom: 1rem;
    transition: background-color 0.3s ease;
}

.control-group, .led-group {
    margin-bottom: 1rem;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    gap: 10px;
}

.input-group {
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 0.5rem;
}

.input-group label {
    display: inline-block;
    width: 130px;
    text-align: right;
    margin-right: 10px;
    font-weight: 500;
}

input[type="text"], select, button {
    padding: 0.6rem;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    font-size: 1rem;
    transition: all 0.2s ease;
    vertical-align: middle;
    background-color: var(--container-bg);
    color: var(--text-color);
}
input[type="color"] {
    padding: 0.2rem;
    height: 40px;
    width: 50px;
}

input[type="text"]:focus, select:focus {
    border-color: #007bff;
    box-shadow: 0 0 0 2px rgba(0, 123, 255, 0.25);
    outline: none;
}

button {
    cursor: pointer;
    border: none;
    color: white;
    min-width: 120px;
    font-weight: 500;
}

#refreshPortsButton {
    background-color: #17a2b8;
}

#connectButton {
    background-color: #007bff;
}

#connectButton.disconnect {
    background-color: var(--color-danger);
}

#sendButton {
    background-color: var(--color-success);
    font-size: 1.1rem;
    padding: 0.8rem 1.2rem;
}

.motor-button {
    background-color: var(--color-success);
}

.motor-button.on {
    background-color: var(--color-danger);
}

#log {
    margin-top: 1rem;
    font-size: 0.9rem;
    color: var(--text-color-light);
    min-height: 1.2em;
    display: flex;
    align-items: center;
    justify-content: center;
}

#status-indicator {
    display: inline-block;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    margin-right: 8px;
    transition: background-color 0.3s ease;
}

#status-indicator.disconnected {
    background-color: var(--color-danger);
}

#status-indicator.connected {
    background-color: var(--color-success);
}

hr {
    border: none;
    border-top: 1px solid var(--hr-color);
    margin: 1.5rem 0;
}

/* Gauge Styles */
#gauges-container {
    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
    gap: 20px;
    width: 100%;
}

.gauge {
    width: 220px;
    text-align: center;
}

.gauge-title {
    font-size: 16px;
    font-weight: 500;
    margin-bottom: 5px;
}
.gauge .gauge-body {
    width: 100%;
    height: 110px;
    position: relative;
}

.gauge .gauge-dial {
    fill: var(--gauge-dial-fill);
    stroke: var(--gauge-dial-stroke);
    stroke-width: 2;
}

.gauge .gauge-needle {
    fill: var(--color-danger);
    stroke: #c02839;
    stroke-width: 1;
    transform-origin: 50px 70px;
    transition: transform 0.2s ease-out;
}

.gauge-value-display {
    font-size: 24px;
    font-weight: bold;
    color: var(--text-color);
    margin-top: 5px;
}

/* LED Indicator Styles */
.led-indicator {
    width: 30px;
    height: 30px;
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.2s ease;
    border: 2px solid #888;
}

.led-indicator.red {
    background-color: #58151c;
}

.led-indicator.red.on {
    background-color: var(--color-danger);
    box-shadow: 0 0 10px var(--color-danger);
}

.led-indicator.green {
    background-color: #12421f;
}

.led-indicator.green.on {
    background-color: var(--color-success);
    box-shadow: 0 0 10px var(--color-success);
}

.mode-switch {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-top: 15px
}

.switch {
    position: relative;
    display: inline-block;
    width: 60px;
    height: 34px
}

.switch input {
    opacity: 0;
    width: 0;
    height: 0
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #555;
    transition: .4s
}

.slider:before {
    position: absolute;
    content: "";
    height: 26px;
    width: 26px;
    left: 4px;
    bottom: 4px;
    background-color: #fff;
    transition: .4s
}

input:checked+.slider {
    background-color: #4CAF50
}

input:focus+.slider {
    box-shadow: 0 0 1px #4CAF50
}

input:checked+.slider:before {
    transform: translateX(26px)
}

.slider.round {
    border-radius: 34px
}

.slider.round:before {
    border-radius: 50%
}

/* New style for invalid input fields */
input.invalid {
    border-color: var(--color-danger);
    box-shadow: 0 0 0 2px rgba(220, 53, 69, 0.25);
}