/* Critical CSS for above-the-fold content */
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
            background: #0a0a0f;
            color: #f0f0f5;
            min-height: 100vh;
            line-height: 1.6;
        }

        header {
            border-bottom: 1px solid #2a2a3a;
            background: #0a0a0f;
            position: sticky;
            top: 0;
            z-index: 100;
        }

        .header-content {
            max-width: 1200px;
            margin: 0 auto;
            padding: 1rem 2rem;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .logo {
            display: flex;
            align-items: center;
            gap: 0.75rem;
            text-decoration: none;
        }

        .logo-icon {
            width: 40px;
            height: 40px;
            background: linear-gradient(135deg, #00e5cc, #4488ff);
            border-radius: 10px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.25rem;
        }

        .logo-text {
            font-weight: 600;
            font-size: 1.25rem;
            color: #f0f0f5;
        }

        .logo-text span {
            color: #00e5cc;
        }

        nav {
            display: flex;
            gap: 2rem;
        }

        nav a {
            color: #8888a0;
            text-decoration: none;
            font-size: 0.9rem;
            font-weight: 500;
        }

        .hero {
            max-width: 1200px;
            margin: 0 auto;
            padding: 4rem 2rem 3rem;
            text-align: center;
        }

        .hero h1 {
            font-size: clamp(2rem, 5vw, 3.5rem);
            font-weight: 700;
            margin-bottom: 1rem;
            background: linear-gradient(135deg, #f0f0f5 0%, #00e5cc 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }

        .hero p {
            font-size: 1.1rem;
            color: #8888a0;
            max-width: 600px;
            margin: 0 auto 2rem;
        }

        .status-bar {
            display: inline-flex;
            align-items: center;
            gap: 0.5rem;
            background: #1a1a24;
            padding: 0.5rem 1rem;
            border-radius: 100px;
            font-size: 0.85rem;
            border: 1px solid #2a2a3a;
        }

        .status-dot {
            width: 8px;
            height: 8px;
            background: #22dd88;
            border-radius: 50%;
            animation: pulse 2s infinite;
        }

        @keyframes pulse {
            0%, 100% { opacity: 1; }
            50% { opacity: 0.5; }
        }
        :root {
            --bg-primary: #0a0a0f;
            --bg-secondary: #12121a;
            --bg-card: #1a1a24;
            --bg-card-hover: #22222e;
            --text-primary: #f0f0f5;
            --text-secondary: #8888a0;
            --text-muted: #555566;
            --accent-cyan: #00e5cc;
            --accent-cyan-dim: #00e5cc33;
            --accent-green: #22dd88;
            --accent-red: #ff4466;
            --accent-orange: #ffaa33;
            --accent-blue: #4488ff;
            --accent-purple: #aa66ff;
            --border-color: #2a2a3a;
            --grid-color: #1a1a2a;
        }

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

        html {
            scroll-behavior: smooth;
        }

        body {
            /* Use system fonts as fallback to prevent invisible text during font loading */
            font-family: 'Outfit', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
            background: var(--bg-primary);
            color: var(--text-primary);
            min-height: 100vh;
            line-height: 1.6;
            background-image: 
                linear-gradient(var(--grid-color) 1px, transparent 1px),
                linear-gradient(90deg, var(--grid-color) 1px, transparent 1px);
            background-size: 50px 50px;
            background-position: -1px -1px;
        }

        /* Header */
        header {
            border-bottom: 1px solid var(--border-color);
            background: var(--bg-primary);
            position: sticky;
            top: 0;
            z-index: 100;
            backdrop-filter: blur(10px);
        }

        .header-content {
            max-width: 1200px;
            margin: 0 auto;
            padding: 1rem 2rem;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .logo {
            display: flex;
            align-items: center;
            gap: 0.75rem;
            text-decoration: none;
        }

        .logo-icon {
            width: 40px;
            height: 40px;
            background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue));
            border-radius: 10px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.25rem;
        }

        .logo-text {
            font-weight: 600;
            font-size: 1.25rem;
            color: var(--text-primary);
        }

        .logo-text span {
            color: var(--accent-cyan);
        }

        nav {
            display: flex;
            gap: 2rem;
        }

        nav a {
            color: var(--text-secondary);
            text-decoration: none;
            font-size: 0.9rem;
            font-weight: 500;
            transition: color 0.2s;
        }

        nav a:hover {
            color: var(--accent-cyan);
        }

        /* Hero Section */
        .hero {
            max-width: 1200px;
            margin: 0 auto;
            padding: 4rem 2rem 3rem;
            text-align: center;
        }

        .hero h1 {
            font-size: clamp(2rem, 5vw, 3.5rem);
            font-weight: 700;
            margin-bottom: 1rem;
            background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-cyan) 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }

        .hero p {
            font-size: 1.1rem;
            color: var(--text-secondary);
            max-width: 600px;
            margin: 0 auto 2rem;
        }

        .status-bar {
            display: inline-flex;
            align-items: center;
            gap: 0.5rem;
            background: var(--bg-card);
            padding: 0.5rem 1rem;
            border-radius: 100px;
            font-family: 'JetBrains Mono', 'Consolas', 'Monaco', 'Courier New', monospace;
            font-size: 0.85rem;
            border: 1px solid var(--border-color);
        }

        .status-dot {
            width: 8px;
            height: 8px;
            background: var(--accent-green);
            border-radius: 50%;
            animation: pulse 2s infinite;
        }

        @keyframes pulse {
            0%, 100% { opacity: 1; }
            50% { opacity: 0.5; }
        }

        /* Main Content */
        main {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 2rem 4rem;
        }

        /* Test Cards Grid */
        .test-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
            gap: 1.5rem;
            margin-bottom: 3rem;
        }

        .test-card {
            background: var(--bg-card);
            border: 1px solid var(--border-color);
            border-radius: 16px;
            padding: 2rem;
            transition: all 0.3s ease;
        }

        .test-card:hover {
            background: var(--bg-card-hover);
            border-color: var(--accent-cyan-dim);
            transform: translateY(-2px);
        }

        .card-header {
            display: flex;
            align-items: center;
            gap: 1rem;
            margin-bottom: 1.5rem;
        }

        .card-icon {
            width: 48px;
            height: 48px;
            border-radius: 12px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.5rem;
        }

        .card-icon.mic {
            background: linear-gradient(135deg, #ff446633, #ff446611);
            border: 1px solid #ff446644;
        }

        .card-icon.speaker {
            background: linear-gradient(135deg, #22dd8833, #22dd8811);
            border: 1px solid #22dd8844;
        }

        .card-icon.record {
            background: linear-gradient(135deg, #aa66ff33, #aa66ff11);
            border: 1px solid #aa66ff44;
        }

        .card-icon.latency {
            background: linear-gradient(135deg, #4488ff33, #4488ff11);
            border: 1px solid #4488ff44;
        }

        .card-icon.db {
            background: linear-gradient(135deg, #ffaa3333, #ffaa3311);
            border: 1px solid #ffaa3344;
        }

        .card-icon.hearing {
            background: linear-gradient(135deg, #22dd8833, #22dd8811);
            border: 1px solid #22dd8844;
        }

        .card-title {
            font-size: 1.25rem;
            font-weight: 600;
        }

        .card-subtitle {
            font-size: 0.85rem;
            color: var(--text-secondary);
        }

        /* Visualizer */
        .visualizer-container {
            background: var(--bg-secondary);
            border-radius: 12px;
            padding: 1.5rem;
            margin-bottom: 1.5rem;
            border: 1px solid var(--border-color);
            min-height: 120px;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .waveform {
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 3px;
            height: 80px;
        }

        .waveform-bar {
            width: 4px;
            background: var(--accent-cyan);
            border-radius: 2px;
            transition: height 0.05s ease;
            opacity: 0.7;
        }

        .waveform-bar.active {
            opacity: 1;
        }

        /* Level Meter */
        .level-meter {
            width: 100%;
            height: 24px;
            background: var(--bg-secondary);
            border-radius: 4px;
            overflow: hidden;
            position: relative;
            border: 1px solid var(--border-color);
        }

        .level-fill {
            height: 100%;
            background: linear-gradient(90deg, var(--accent-green), var(--accent-orange), var(--accent-red));
            transition: width 0.05s ease;
            width: 0%;
        }

        .level-markers {
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            display: flex;
            justify-content: space-between;
            padding: 0 4px;
            align-items: center;
            pointer-events: none;
        }

        .level-markers span {
            font-family: 'JetBrains Mono', 'Consolas', 'Monaco', 'Courier New', monospace;
            font-size: 0.6rem;
            color: var(--text-muted);
        }

        /* Buttons */
        .btn {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: 0.5rem;
            padding: 0.875rem 1.5rem;
            border-radius: 10px;
            font-family: 'Outfit', sans-serif;
            font-size: 0.95rem;
            font-weight: 500;
            cursor: pointer;
            transition: all 0.2s ease;
            border: none;
            width: 100%;
        }

        .btn-primary {
            background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue));
            color: var(--bg-primary);
        }

        .btn-primary:hover {
            transform: scale(1.02);
            box-shadow: 0 4px 20px var(--accent-cyan-dim);
        }

        .btn-danger {
            background: linear-gradient(135deg, var(--accent-red), #cc3355);
            color: white;
        }

        .btn-secondary {
            background: var(--bg-secondary);
            color: var(--text-primary);
            border: 1px solid var(--border-color);
        }

        .btn-secondary:hover {
            background: var(--bg-card-hover);
            border-color: var(--accent-cyan-dim);
        }

        .btn-record {
            background: linear-gradient(135deg, var(--accent-purple), #8844dd);
            color: white;
        }

        .btn-record:hover {
            transform: scale(1.02);
            box-shadow: 0 4px 20px rgba(170, 102, 255, 0.3);
        }

        .btn-record.recording {
            background: linear-gradient(135deg, var(--accent-red), #cc3355);
            animation: recordPulse 1s ease infinite;
        }

        @keyframes recordPulse {
            0%, 100% { box-shadow: 0 0 0 0 rgba(255, 68, 102, 0.5); }
            50% { box-shadow: 0 0 0 15px rgba(255, 68, 102, 0); }
        }

        .btn:disabled {
            opacity: 0.5;
            cursor: not-allowed;
            transform: none !important;
        }

        /* Status Messages */
        .status-message {
            font-family: 'JetBrains Mono', 'Consolas', 'Monaco', 'Courier New', monospace;
            font-size: 0.8rem;
            text-align: center;
            margin-top: 1rem;
            padding: 0.5rem;
            border-radius: 6px;
            background: var(--bg-secondary);
        }

        .status-message.success {
            color: var(--accent-green);
            border: 1px solid #22dd8833;
        }

        .status-message.error {
            color: var(--accent-red);
            border: 1px solid #ff446633;
        }

        .status-message.info {
            color: var(--accent-cyan);
            border: 1px solid var(--accent-cyan-dim);
        }

        /* Speaker Test Tones */
        .tone-buttons {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 0.5rem;
            margin-bottom: 1rem;
        }

        .tone-btn {
            padding: 0.75rem;
            background: var(--bg-secondary);
            border: 1px solid var(--border-color);
            border-radius: 8px;
            color: var(--text-primary);
            font-family: 'JetBrains Mono', 'Consolas', 'Monaco', 'Courier New', monospace;
            font-size: 0.8rem;
            cursor: pointer;
            transition: all 0.2s;
        }

        .tone-btn:hover {
            background: var(--bg-card-hover);
            border-color: var(--accent-cyan-dim);
        }

        .tone-btn.active {
            background: var(--accent-cyan-dim);
            border-color: var(--accent-cyan);
            color: var(--accent-cyan);
        }

        /* Channel Test */
        .channel-test {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 0.75rem;
            margin-bottom: 1rem;
        }

        .channel-btn {
            padding: 1rem;
            background: var(--bg-secondary);
            border: 1px solid var(--border-color);
            border-radius: 10px;
            color: var(--text-secondary);
            font-weight: 500;
            cursor: pointer;
            transition: all 0.2s;
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 0.25rem;
        }

        .channel-btn span {
            font-size: 1.5rem;
        }

        .channel-btn:hover {
            background: var(--bg-card-hover);
            border-color: var(--accent-green);
            color: var(--accent-green);
        }

        .channel-btn.playing {
            background: #22dd8822;
            border-color: var(--accent-green);
            color: var(--accent-green);
            animation: channelPulse 0.5s ease infinite;
        }

        @keyframes channelPulse {
            0%, 100% { box-shadow: 0 0 0 0 #22dd8844; }
            50% { box-shadow: 0 0 0 10px #22dd8800; }
        }

        /* Recording Section */
        .recording-area {
            text-align: center;
        }

        .recording-timer {
            display: none;
            align-items: center;
            justify-content: center;
            gap: 0.5rem;
            font-family: 'JetBrains Mono', 'Consolas', 'Monaco', 'Courier New', monospace;
            font-size: 2rem;
            color: var(--accent-red);
            margin-bottom: 1rem;
        }

        .recording-timer.active {
            display: flex;
        }

        .timer-dot {
            width: 12px;
            height: 12px;
            background: var(--accent-red);
            border-radius: 50%;
            animation: blink 1s ease infinite;
        }

        @keyframes blink {
            0%, 100% { opacity: 1; }
            50% { opacity: 0.3; }
        }

        .playback-controls {
            display: none;
            gap: 0.5rem;
            margin-top: 1rem;
        }

        .playback-controls.active {
            display: flex;
        }

        .playback-btn {
            flex: 1;
        }

        .recording-icon {
            font-size: 3rem;
            margin-bottom: 1rem;
            opacity: 0.5;
        }

        .recording-icon.active {
            opacity: 1;
            animation: pulseIcon 1s ease infinite;
        }

        @keyframes pulseIcon {
            0%, 100% { transform: scale(1); }
            50% { transform: scale(1.1); }
        }

        /* Latency Display */
        .latency-results {
            display: none;
        }

        .latency-results.active {
            display: block;
        }

        .latency-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 1rem;
            margin-bottom: 1rem;
        }

        .latency-item {
            background: var(--bg-secondary);
            border-radius: 8px;
            padding: 1rem;
            text-align: center;
            border: 1px solid var(--border-color);
        }

        .latency-item-value {
            font-family: 'JetBrains Mono', 'Consolas', 'Monaco', 'Courier New', monospace;
            font-size: 1.5rem;
            font-weight: 600;
            color: var(--accent-cyan);
        }

        .latency-item-label {
            font-size: 0.75rem;
            color: var(--text-secondary);
            margin-top: 0.25rem;
        }

        .latency-total {
            background: var(--bg-secondary);
            border-radius: 8px;
            padding: 1.5rem;
            text-align: center;
            border: 1px solid var(--accent-cyan-dim);
        }

        .latency-total-value {
            font-family: 'JetBrains Mono', 'Consolas', 'Monaco', 'Courier New', monospace;
            font-size: 2.5rem;
            font-weight: 600;
            color: var(--accent-cyan);
        }

        .latency-total-label {
            font-size: 0.85rem;
            color: var(--text-secondary);
        }

        .latency-rating {
            margin-top: 0.5rem;
            font-size: 0.9rem;
            font-weight: 600;
        }

        .latency-rating.excellent { color: var(--accent-green); }
        .latency-rating.good { color: var(--accent-cyan); }
        .latency-rating.fair { color: var(--accent-orange); }
        .latency-rating.poor { color: var(--accent-red); }

        .latency-placeholder {
            text-align: center;
            padding: 2rem;
            color: var(--text-secondary);
        }

        .latency-placeholder-icon {
            font-size: 3rem;
            margin-bottom: 1rem;
            opacity: 0.5;
        }

        /* Sound Level Meter (dB) */
        .db-display {
            text-align: center;
            padding: 1rem;
        }

        .db-value {
            font-family: 'JetBrains Mono', 'Consolas', 'Monaco', 'Courier New', monospace;
            font-size: 3.5rem;
            font-weight: 600;
            color: var(--accent-orange);
            line-height: 1;
        }

        .db-unit {
            font-size: 1.25rem;
            color: var(--text-secondary);
            margin-top: 0.25rem;
        }

        .db-label {
            font-size: 0.8rem;
            color: var(--text-muted);
            margin-top: 0.5rem;
        }

        .db-scale {
            margin-bottom: 1.5rem;
        }

        .db-bar-container {
            position: relative;
            height: 32px;
            background: var(--bg-secondary);
            border-radius: 6px;
            overflow: hidden;
            border: 1px solid var(--border-color);
        }

        .db-bar {
            height: 100%;
            width: 0%;
            background: linear-gradient(90deg, 
                var(--accent-green) 0%, 
                var(--accent-green) 40%, 
                var(--accent-orange) 60%, 
                var(--accent-red) 100%
            );
            transition: width 0.1s ease;
            border-radius: 4px;
        }

        .db-zones {
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            display: flex;
            align-items: center;
            justify-content: space-around;
            pointer-events: none;
            font-size: 0.7rem;
            font-weight: 500;
        }

        .zone-quiet { color: var(--accent-green); }
        .zone-moderate { color: var(--accent-orange); }
        .zone-loud { color: var(--accent-red); }

        .db-markers {
            display: flex;
            justify-content: space-between;
            padding: 0.25rem 0.25rem 0;
            font-family: 'JetBrains Mono', 'Consolas', 'Monaco', 'Courier New', monospace;
            font-size: 0.65rem;
            color: var(--text-muted);
        }

        /* Hearing Test */
        .hearing-display {
            text-align: center;
            padding: 1rem;
        }

        .hearing-freq {
            font-family: 'JetBrains Mono', 'Consolas', 'Monaco', 'Courier New', monospace;
            font-size: 3rem;
            font-weight: 600;
            color: var(--accent-green);
            line-height: 1;
        }

        .hearing-freq-unit {
            font-size: 1rem;
            color: var(--text-secondary);
            margin-top: 0.25rem;
        }

        .hearing-status {
            font-size: 0.85rem;
            color: var(--text-muted);
            margin-top: 0.5rem;
        }

        .hearing-controls {
            margin-bottom: 1rem;
        }

        .frequency-buttons {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 0.4rem;
        }

        .freq-btn {
            padding: 0.6rem 0.4rem;
            background: var(--bg-secondary);
            border: 1px solid var(--border-color);
            border-radius: 6px;
            color: var(--text-primary);
            font-family: 'JetBrains Mono', 'Consolas', 'Monaco', 'Courier New', monospace;
            font-size: 0.7rem;
            cursor: pointer;
            transition: all 0.2s;
        }

        .freq-btn:hover {
            background: var(--bg-card-hover);
            border-color: var(--accent-green);
            color: var(--accent-green);
        }

        .freq-btn.active {
            background: var(--accent-green);
            border-color: var(--accent-green);
            color: var(--bg-primary);
        }

        .freq-btn.high {
            border-color: #ffaa3344;
        }

        .freq-btn.high:hover {
            border-color: var(--accent-orange);
            color: var(--accent-orange);
        }

        .freq-btn.ultra {
            border-color: #ff446644;
        }

        .freq-btn.ultra:hover {
            border-color: var(--accent-red);
            color: var(--accent-red);
        }

        .freq-btn.playing {
            animation: freqPulse 0.3s ease;
        }

        @keyframes freqPulse {
            0%, 100% { transform: scale(1); }
            50% { transform: scale(0.95); }
        }

        .hearing-result {
            margin-top: 1rem;
            padding: 1rem;
            background: var(--bg-secondary);
            border-radius: 8px;
            border: 1px solid var(--border-color);
            display: none;
        }

        .hearing-result.active {
            display: block;
        }

        .hearing-result-title {
            font-size: 0.85rem;
            color: var(--text-secondary);
            margin-bottom: 0.5rem;
        }

        .hearing-result-value {
            font-family: 'JetBrains Mono', 'Consolas', 'Monaco', 'Courier New', monospace;
            font-size: 1.25rem;
            font-weight: 600;
            color: var(--accent-cyan);
        }

        /* Device Info */
        .device-info {
            background: var(--bg-secondary);
            border-radius: 8px;
            padding: 1rem;
            margin-top: 1rem;
            font-family: 'JetBrains Mono', 'Consolas', 'Monaco', 'Courier New', monospace;
            font-size: 0.75rem;
            color: var(--text-secondary);
        }

        .device-info-row {
            display: flex;
            justify-content: space-between;
            padding: 0.25rem 0;
            border-bottom: 1px solid var(--border-color);
        }

        .device-info-row:last-child {
            border-bottom: none;
        }

        .device-info-label {
            color: var(--text-muted);
        }

        .device-info-value {
            color: var(--text-primary);
            text-align: right;
            max-width: 60%;
            overflow: hidden;
            text-overflow: ellipsis;
            white-space: nowrap;
        }

        /* Ad Placeholder */
        .ad-container {
            background: var(--bg-card);
            border: 1px dashed var(--border-color);
            border-radius: 12px;
            padding: 2rem;
            text-align: center;
            margin: 2rem 0;
        }

        .ad-label {
            font-size: 0.75rem;
            color: var(--text-muted);
            text-transform: uppercase;
            letter-spacing: 0.1em;
        }

        /* Guide section */
        .guide-section {
            margin-top: 4rem;
            max-width: 900px;
            margin-left: auto;
            margin-right: auto;
        }

        .guide-section h2 {
            font-size: 1.75rem;
            margin-bottom: 1rem;
            text-align: center;
        }

        .guide-section .guide-intro {
            color: var(--text-secondary);
            text-align: center;
            margin-bottom: 2rem;
            padding: 0 1rem;
        }

        .guide-card {
            background: var(--bg-card);
            border: 1px solid var(--border-color);
            border-radius: 12px;
            padding: 1.75rem;
            margin-bottom: 1rem;
        }

        .guide-card h3 {
            font-size: 1.1rem;
            font-weight: 600;
            color: var(--accent-cyan);
            margin-bottom: 0.75rem;
        }

        .guide-card p,
        .guide-card li {
            color: var(--text-secondary);
            font-size: 0.95rem;
        }

        .guide-card p {
            margin-bottom: 0.75rem;
        }

        .guide-card ul {
            margin-left: 1.25rem;
            margin-bottom: 0.75rem;
        }

        .guide-card a {
            color: var(--accent-cyan);
        }

        .guide-card .last-reviewed {
            display: block;
            margin-top: 1.5rem;
            text-align: center;
            color: var(--text-muted);
            font-size: 0.85rem;
        }

        /* FAQ Section */
        .faq-section {
            margin-top: 4rem;
        }

        .faq-section h2 {
            font-size: 1.75rem;
            margin-bottom: 1.5rem;
            text-align: center;
        }

        .faq-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: 1rem;
        }

        .faq-item {
            background: var(--bg-card);
            border: 1px solid var(--border-color);
            border-radius: 12px;
            padding: 1.5rem;
        }

        .faq-item h3 {
            font-size: 1rem;
            font-weight: 600;
            margin-bottom: 0.5rem;
            color: var(--accent-cyan);
        }

        .faq-item p {
            font-size: 0.9rem;
            color: var(--text-secondary);
        }

        /* Footer */
        footer {
            border-top: 1px solid var(--border-color);
            margin-top: 4rem;
            padding: 2rem;
            text-align: center;
        }

        .footer-links {
            display: flex;
            justify-content: center;
            gap: 2rem;
            margin-bottom: 1.5rem;
            flex-wrap: wrap;
        }

        .footer-links a {
            color: var(--text-secondary);
            text-decoration: none;
            font-size: 0.9rem;
            transition: color 0.2s;
        }

        .footer-links a:hover {
            color: var(--accent-cyan);
        }

        .footer-copy {
            color: var(--text-muted);
            font-size: 0.85rem;
        }

        .footer-tests {
            margin-top: 1rem;
            font-size: 0.8rem;
        }

        .footer-tests a {
            color: var(--text-secondary);
            text-decoration: none;
        }

        .footer-tests a:hover {
            color: var(--accent-cyan);
        }

        /* Responsive */
        @media (max-width: 768px) {
            .header-content {
                flex-direction: column;
                gap: 1rem;
            }

            nav {
                gap: 1rem;
            }

            .test-grid {
                grid-template-columns: 1fr;
            }

            .hero {
                padding: 2rem 1rem;
            }

            main {
                padding: 0 1rem 2rem;
            }

            .tone-buttons {
                grid-template-columns: repeat(2, 1fr);
            }

            .footer-links {
                gap: 1rem;
            }

            .latency-grid {
                grid-template-columns: 1fr;
            }
        }

        /* Permission Modal */
        .modal-overlay {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: rgba(0, 0, 0, 0.8);
            z-index: 1000;
            align-items: center;
            justify-content: center;
            padding: 1rem;
        }

        .modal-overlay.active {
            display: flex;
        }

        .modal {
            background: var(--bg-card);
            border: 1px solid var(--border-color);
            border-radius: 16px;
            padding: 2rem;
            max-width: 400px;
            text-align: center;
        }

        .modal h3 {
            margin-bottom: 1rem;
        }

        .modal p {
            color: var(--text-secondary);
            margin-bottom: 1.5rem;
            font-size: 0.9rem;
        }

        .modal-buttons {
            display: flex;
            gap: 0.75rem;
        }

        .modal-buttons .btn {
            flex: 1;
        }

/* ============================================
   SHARED ARTICLE / GUIDE / TOOL-PAGE STYLES
   ============================================ */

body.page {
    font-family: 'Outfit', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    line-height: 1.65;
    background-image:
        linear-gradient(var(--grid-color) 1px, transparent 1px),
        linear-gradient(90deg, var(--grid-color) 1px, transparent 1px);
    background-size: 50px 50px;
    background-position: -1px -1px;
}

/* Primary navigation (tools + guides) */
.nav-primary { display: flex; gap: 1.5rem; align-items: center; flex-wrap: wrap; }
.nav-primary a { color: var(--text-secondary); text-decoration: none; font-size: 0.9rem; font-weight: 500; transition: color 0.2s; }
.nav-primary a:hover, .nav-primary a[aria-current="page"] { color: var(--accent-cyan); }

/* Breadcrumbs */
.breadcrumbs { max-width: 1200px; margin: 0 auto; padding: 1rem 2rem 0; font-size: 0.82rem; color: var(--text-muted); }
.breadcrumbs a { color: var(--text-secondary); text-decoration: none; }
.breadcrumbs a:hover { color: var(--accent-cyan); }
.breadcrumbs span { margin: 0 0.4rem; }

/* Article wrapper */
.article-wrap { max-width: 820px; margin: 0 auto; padding: 3rem 2rem; }
.article-wrap h1 {
    font-size: 2.35rem; font-weight: 700; margin-bottom: 0.75rem; line-height: 1.2;
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-cyan) 100%);
    -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.article-wrap .standfirst { color: var(--text-secondary); font-size: 1.08rem; margin-bottom: 1rem; }
.last-updated { font-size: 0.85rem; color: var(--text-muted); margin-bottom: 2.5rem; }

article p { color: var(--text-secondary); margin-bottom: 1rem; }
article h2 { color: var(--text-primary); font-size: 1.5rem; margin: 2.5rem 0 1rem; padding-bottom: 0.5rem; border-bottom: 1px solid var(--border-color); scroll-margin-top: 90px; }
article h3 { color: var(--accent-cyan); font-size: 1.1rem; margin: 1.6rem 0 0.6rem; }
article h4 { color: var(--text-primary); font-size: 0.98rem; margin: 1.2rem 0 0.4rem; }
article ul, article ol { color: var(--text-secondary); margin: 0 0 1rem 1.5rem; }
article li { margin-bottom: 0.4rem; }
article a { color: var(--accent-cyan); }
article strong { color: var(--text-primary); }

/* Table of contents */
.toc { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 12px; padding: 1.25rem 1.5rem; margin: 0 0 2rem; }
.toc h2 { font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.08em; color: var(--text-muted); border: none; margin: 0 0 0.75rem; padding: 0; }
.toc ol { margin: 0 0 0 1.1rem; columns: 2; column-gap: 2rem; }
.toc li { margin-bottom: 0.3rem; font-size: 0.9rem; }
@media (max-width: 640px) { .toc ol { columns: 1; } }

/* Callout / checklist / related */
.callout { background: var(--accent-cyan-dim); border: 1px solid var(--accent-cyan); border-radius: 10px; padding: 1.25rem 1.5rem; margin: 1.5rem 0; color: var(--text-primary); }
.callout p { color: var(--text-primary); margin-bottom: 0; }
.callout strong { color: var(--accent-cyan); }
.callout.warn { background: #ffaa3322; border-color: var(--accent-orange); }
.callout.warn strong { color: var(--accent-orange); }

.checklist { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 12px; padding: 1.5rem 1.75rem; margin: 1.5rem 0; }
.checklist h3 { margin-top: 0; }
.checklist ol, .checklist ul { margin-bottom: 0; }

.related { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 12px; padding: 1.5rem; margin-top: 3rem; }
.related h3 { margin-top: 0; color: var(--accent-cyan); font-size: 1rem; }
.related ul { margin-bottom: 0; list-style: none; margin-left: 0; }
.related li { margin-bottom: 0.45rem; }

.back-link { display: inline-flex; align-items: center; gap: 0.5rem; color: var(--accent-cyan); text-decoration: none; font-weight: 500; margin-top: 2rem; }

/* Data tables */
.data-table { width: 100%; border-collapse: collapse; margin: 1.5rem 0; font-size: 0.92rem; }
.data-table th, .data-table td { text-align: left; padding: 0.65rem 0.85rem; border-bottom: 1px solid var(--border-color); color: var(--text-secondary); }
.data-table th { color: var(--text-primary); font-weight: 600; background: var(--bg-secondary); }
.data-table tr:hover td { background: var(--bg-card); }
.table-scroll { overflow-x: auto; }

/* FAQ on article pages */
.faq-list { margin-top: 1rem; }
.faq-list details { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 10px; padding: 0.9rem 1.2rem; margin-bottom: 0.6rem; }
.faq-list summary { cursor: pointer; color: var(--text-primary); font-weight: 500; }
.faq-list details p { margin: 0.7rem 0 0; }

/* Tool page: embedded widget */
.tool-shell { max-width: 760px; margin: 0 auto 1rem; padding: 0 2rem; }
.tool-shell .test-card:hover { transform: none; }

/* Hub grid of tool/guide links */
.link-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 1rem; margin: 1.5rem 0; }
.link-card { display: block; background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 12px; padding: 1.1rem 1.25rem; text-decoration: none; transition: all 0.2s; }
.link-card:hover { border-color: var(--accent-cyan-dim); background: var(--bg-card-hover); transform: translateY(-2px); }
.link-card strong { display: block; color: var(--text-primary); margin-bottom: 0.25rem; font-size: 0.98rem; }
.link-card span { color: var(--text-secondary); font-size: 0.85rem; }

@media (max-width: 768px) {
    .header-content { flex-direction: column; gap: 1rem; }
    .nav-primary { gap: 1rem; justify-content: center; }
    .article-wrap { padding: 2rem 1rem; }
    .article-wrap h1 { font-size: 1.75rem; }
    .tool-shell { padding: 0 1rem; }
    .breadcrumbs { padding: 1rem 1rem 0; }
}

/* Mobile: keep tool cards inside the viewport */
@media (max-width: 768px) {
    .header-content { padding: 1rem; }
    .nav-primary { gap: 0.75rem 1rem; flex-wrap: wrap; justify-content: center; }
    .test-card { padding: 1.5rem 1.25rem; }
    .visualizer-container { padding: 1rem; min-width: 0; overflow: hidden; }
    .waveform { gap: 2px; width: 100%; }
    .waveform-bar { width: 3px; min-width: 0; flex: 1 1 3px; max-width: 4px; }
    .tone-buttons { grid-template-columns: repeat(2, 1fr); }
    .latency-grid { grid-template-columns: 1fr; }
    .frequency-buttons { grid-template-columns: repeat(3, 1fr); }
}

/* Header wraps rather than overflowing on narrow desktop widths */
.header-content { flex-wrap: wrap; gap: 0.75rem 1rem; }
.nav-primary { justify-content: flex-end; }

/* Intro block sits above the tool; body continues below it */
.article-wrap { padding-bottom: 1.5rem; }
.article-wrap--body { padding-top: 1.5rem; }
.breadcrumbs + .article-wrap { padding-top: 2rem; }