:root {
            --bg-color: #020617;
            --card-bg: rgba(15, 23, 42, 0.85);
            --text-primary: #f8fafc;
            --text-secondary: #94a3b8;
            --accent-blue: #38bdf8;
            --accent-green: #34d399;
            --accent-yellow: #fbbf24;
            --accent-white: #f1f5f9;
            --accent-red: #f87171;
            --led-off: #1e293b;
            --font-main: 'Outfit', 'Inter', system-ui, sans-serif;
        }

        @import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;400;600;800&display=swap');

        * {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
            -webkit-tap-highlight-color: transparent;
            user-select: none;
        }

        body {
            background-color: var(--bg-color);
            color: var(--text-primary);
            font-family: var(--font-main);
            display: flex;
            align-items: center;
            justify-content: center;
            min-height: 100vh;
            overflow: hidden;
            background: 
                radial-gradient(circle at 0% 0%, rgba(14, 165, 233, 0.15) 0%, transparent 50%),
                radial-gradient(circle at 100% 100%, rgba(16, 185, 129, 0.1) 0%, transparent 50%),
                #020617;
        }

        .container {
            width: 90%;
            max-width: 400px;
            display: flex;
            flex-direction: column;
            gap: 1.5rem;
        }

        /* Branding */
        .brand {
            text-align: center;
        }

        .brand h1 {
            font-weight: 800;
            font-size: 2.5rem;
            letter-spacing: -0.05em;
            margin-bottom: 0.25rem;
            background: linear-gradient(to bottom right, #fff 30%, #64748b);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
        }

        .brand p {
            color: var(--text-secondary);
            font-size: 0.75rem;
            text-transform: uppercase;
            letter-spacing: 0.2em;
        }

        /* Dashboard */
        .dashboard {
            background: var(--card-bg);
            border-radius: 2rem;
            padding: 2rem;
            border: 1px solid rgba(255, 255, 255, 0.05);
            box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
            backdrop-filter: blur(12px);
            display: flex;
            flex-direction: column;
            gap: 2rem;
        }

        /* LED Panel */
        .status-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 0 0.5rem;
        }

        .indicator {
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 0.5rem;
        }

        .led-label {
            font-size: 0.6rem;
            font-weight: 600;
            color: var(--text-secondary);
            text-transform: uppercase;
            letter-spacing: 0.1em;
        }

        .led {
            width: 12px;
            height: 12px;
            border-radius: 50%;
            background: var(--led-off);
            transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
            position: relative;
        }

        .led::after {
            content: '';
            position: absolute;
            inset: -4px;
            border-radius: 50%;
            border: 1px solid rgba(255, 255, 255, 0.05);
        }

        /* LED Animations */
        .led-conn.disconnected {
            background: var(--accent-yellow);
            box-shadow: 0 0 15px var(--accent-yellow);
        }

        .led-conn.paired {
            background: var(--accent-blue);
            animation: blink-blue 1s infinite steps(1);
        }

        @keyframes blink-blue {
            0%, 50% { background: var(--accent-blue); box-shadow: 0 0 20px var(--accent-blue); }
            50.1%, 100% { background: var(--led-off); box-shadow: none; }
        }

        .led-mode.tx-active {
            background: var(--accent-green);
            box-shadow: 0 0 25px var(--accent-green);
            animation: pulse-glow 2s infinite alternate;
        }

        .led-mode.rx-active {
            background: var(--accent-white);
            box-shadow: 0 0 25px var(--accent-white);
            animation: pulse-glow 2s infinite alternate;
        }

        @keyframes pulse-glow {
            from { opacity: 0.6; transform: scale(0.9); }
            to { opacity: 1; transform: scale(1.1); }
        }

        /* Visualizer */
        .visualizer-container {
            height: 40px;
            width: 100%;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 3px;
        }

        .bar {
            width: 3px;
            height: 100%;
            background: var(--led-off);
            border-radius: 2px;
            transition: height 0.1s;
        }

        .bar.active-tx { background: var(--accent-green); }
        .bar.active-rx { background: var(--accent-white); }

        /* Mode Buttons */
        .modes {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 1rem;
        }

        .mode-btn {
            background: rgba(255, 255, 255, 0.03);
            border: 1px solid rgba(255, 255, 255, 0.05);
            padding: 1.25rem;
            border-radius: 1.25rem;
            cursor: pointer;
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 0.5rem;
            transition: all 0.3s;
        }

        .mode-btn span:first-child { font-size: 1.5rem; filter: grayscale(1); opacity: 0.5; }
        .mode-btn span:last-child { font-size: 0.75rem; font-weight: 600; color: var(--text-secondary); }

        .mode-btn.active.tx { 
            background: rgba(16, 185, 129, 0.1); 
            border-color: var(--accent-green); 
        }
        .mode-btn.active.rx { 
            background: rgba(241, 245, 249, 0.05); 
            border-color: var(--accent-white); 
        }
        
        .mode-btn.active span:first-child { filter: grayscale(0); opacity: 1; }
        .mode-btn.active span:last-child { color: var(--text-primary); }

        /* Control Button */
        .controls {
            display: flex;
            flex-direction: column;
            gap: 1rem;
        }

        .main-btn {
            padding: 1.5rem;
            border-radius: 1.25rem;
            border: none;
            font-family: inherit;
            font-weight: 800;
            font-size: 1.1rem;
            letter-spacing: 0.05em;
            text-transform: uppercase;
            cursor: pointer;
            transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 1rem;
        }

        .btn-pair {
            background: var(--accent-blue);
            color: #000;
        }

        .btn-talk {
            background: var(--led-off);
            color: var(--text-secondary);
        }

        .btn-talk.ready {
            background: var(--text-primary);
            color: #000;
            box-shadow: 0 10px 30px rgba(255, 255, 255, 0.1);
        }

        .btn-talk.active {
            background: var(--accent-red);
            color: #fff;
            animation: pulse-button 2s infinite;
        }

        @keyframes pulse-button {
            0% { box-shadow: 0 0 0 0 rgba(239, 68, 68, 0.7); }
            70% { box-shadow: 0 0 0 20px rgba(239, 68, 68, 0); }
            100% { box-shadow: 0 0 0 0 rgba(239, 68, 68, 0); }
        }

        .main-btn:disabled {
            opacity: 0.3;
            cursor: not-allowed;
        }

        /* Status Footer */
        .status-text {
            text-align: center;
            font-size: 0.7rem;
            color: var(--text-secondary);
            font-weight: 500;
            min-height: 1rem;
        }

            /* Audio Settings Enhancement */
        .audio-settings {
            display: flex;
            flex-direction: column;
            gap: 1.5rem;
            background: rgba(15, 23, 42, 0.9);
            padding: 1.5rem;
            border-radius: 2rem;
            border: 1px solid rgba(255, 255, 255, 0.1);
            box-shadow: inset 0 0 20px rgba(0, 0, 0, 0.3);
        }

        .setting-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 0.5rem;
        }

        .profile-grid {
            display: grid;
            grid-template-columns: repeat(5, 1fr);
            gap: 0.5rem;
        }

        .profile-box {
            background: rgba(255, 255, 255, 0.05);
            border: 1px solid rgba(255, 255, 255, 0.1);
            padding: 0.75rem 0.25rem;
            border-radius: 1rem;
            font-size: 0.7rem;
            font-weight: 700;
            text-align: center;
            color: var(--text-secondary);
            transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
            cursor: pointer;
            display: block;
            text-transform: uppercase;
        }

        .profile-option input:checked ~ .profile-box {
            background: linear-gradient(135deg, rgba(14, 165, 233, 0.2), rgba(14, 165, 233, 0.05));
            border-color: var(--accent-blue);
            color: var(--text-primary);
            box-shadow: 0 0 15px rgba(14, 165, 233, 0.3);
            transform: translateY(-2px);
        }

        /* Intensity Controls */
        .intensity-panel {
            display: flex;
            align-items: center;
            justify-content: space-between;
            background: rgba(0, 0, 0, 0.2);
            padding: 0.75rem 1rem;
            border-radius: 1.25rem;
            border: 1px solid rgba(255, 255, 255, 0.05);
        }

        .intensity-label {
            font-size: 0.7rem;
            font-weight: 600;
            color: var(--text-secondary);
            text-transform: uppercase;
        }

        .intensity-btns {
            display: flex;
            gap: 0.5rem;
            align-items: center;
        }

        .i-btn {
            width: 32px;
            height: 32px;
            border-radius: 50%;
            border: 1px solid rgba(255, 255, 255, 0.1);
            background: rgba(255, 255, 255, 0.05);
            color: var(--text-primary);
            font-size: 1.2rem;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            transition: all 0.2s;
        }

        .i-btn:hover {
            background: rgba(255, 255, 255, 0.1);
            border-color: var(--text-primary);
        }

        .i-btn:active {
            transform: scale(0.9);
        }

        .intensity-value {
            min-width: 3ch;
            text-align: center;
            font-weight: 800;
            color: var(--accent-blue);
            font-variant-numeric: tabular-nums;
        }

        /* Noise Toggle */
        .noise-container {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 0.5rem 0.5rem 0;
        }

        .noise-toggle {
            display: flex;
            align-items: center;
            gap: 0.75rem;
            cursor: pointer;
        }

        .radio-custom {
            width: 18px;
            height: 18px;
            border: 2px solid var(--text-secondary);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: all 0.2s;
        }

        .noise-toggle input { display: none; }
        .noise-toggle input:checked + .radio-custom {
            border-color: var(--accent-green);
        }

        .noise-toggle input:checked + .radio-custom::after {
            content: '';
            width: 10px;
            height: 10px;
            background: var(--accent-green);
            border-radius: 50%;
            box-shadow: 0 0 10px var(--accent-green);
        }

        .noise-text {
            font-size: 0.75rem;
            font-weight: 600;
            color: var(--text-secondary);
        }

        .noise-toggle input:checked ~ .noise-text {
            color: var(--accent-green);
        }

        /* Volume Slider */
        .volume-container {
            display: flex;
            align-items: center;
            gap: 1rem;
        }

        input[type="range"] {
            -webkit-appearance: none;
            width: 100%;
            height: 4px;
            background: var(--led-off);
            border-radius: 2px;
            outline: none;
        }

        input[type="range"]::-webkit-slider-thumb {
            -webkit-appearance: none;
            appearance: none;
            width: 16px;
            height: 16px;
            background: var(--text-primary);
            border-radius: 50%;
            cursor: pointer;
            box-shadow: 0 0 10px rgba(255, 255, 255, 0.3);
            transition: transform 0.2s;
        }

        input[type="range"]::-webkit-slider-thumb:hover {
            transform: scale(1.2);
        }

        /* Icons */
        .icon { width: 20px; height: 20px; fill: currentColor; }