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

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

html {
    overflow-x: hidden;
}

body {
    font-family: 'Arial', 'Helvetica', sans-serif;
    background: #000000;
    min-height: 100vh;
    min-height: -webkit-fill-available;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: max(12px, env(safe-area-inset-top)) max(12px, env(safe-area-inset-right)) max(12px, env(safe-area-inset-bottom)) max(12px, env(safe-area-inset-left));
    color: #000;
    -webkit-text-size-adjust: 100%;
}

.container {
    background: #FFFFFF;
    border: 6px solid #000000;
    border-radius: 0;
    box-shadow: 8px 8px 0px 0px #000000;
    padding: 20px;
    max-width: 600px;
    width: 100%;
    min-width: 0;
    position: relative;
}

.tuner-container {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.frequency-display {
    text-align: center;
    padding: 20px 16px;
    background: #FFEB3B;
    border: 4px solid #000000;
    border-radius: 0;
    position: relative;
}

.frequency-value {
    font-size: 2.8em;
    font-weight: 900;
    color: #000000;
    margin-bottom: 6px;
    letter-spacing: -1px;
}

.note-display {
    font-size: 2em;
    font-weight: 900;
    color: #000000;
    text-transform: uppercase;
    letter-spacing: 3px;
}

.tuning-meter {
    position: relative;
    height: 100px;
    background: #FFFFFF;
    border: 4px solid #000000;
    border-radius: 0;
    margin: 20px 0;
    overflow: visible;
}

.meter-needle {
    position: absolute;
    top: 0;
    left: 50%;
    width: 6px;
    height: 100%;
    background: #E53935;
    transform-origin: bottom center;
    transform: translateX(-50%) rotate(0deg);
    transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1),
                background 0.3s ease;
    z-index: 2;
    border-left: 2px solid #000000;
    border-right: 2px solid #000000;
}

.meter-needle::before {
    content: '';
    position: absolute;
    top: -15px;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 0;
    border-left: 10px solid transparent;
    border-right: 10px solid transparent;
    border-top: 20px solid #E53935;
    transition: border-top-color 0.2s ease;
}

.meter-needle[data-color="#4CAF50"]::before {
    border-top-color: #4CAF50;
}

.meter-needle[data-color="#FF9800"]::before {
    border-top-color: #FF9800;
}

.meter-needle[data-color="#2196F3"]::before {
    border-top-color: #2196F3;
}

.meter-scale {
    position: absolute;
    bottom: 10px;
    left: 0;
    right: 0;
    display: flex;
    justify-content: space-between;
    padding: 0 20px;
}

.scale-mark {
    font-size: 0.9em;
    color: #000000;
    font-weight: 900;
    text-transform: uppercase;
}

.center-mark {
    color: #000000;
    font-weight: 900;
    font-size: 1.2em;
    background: #FFEB3B;
    padding: 4px 8px;
    border: 2px solid #000000;
}

.string-selector {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: 8px;
}

.string-button {
    background: #2196F3;
    color: #FFFFFF;
    padding: 12px 8px;
    border: 3px solid #000000;
    border-radius: 0;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    font-weight: 900;
    text-transform: uppercase;
}

.string-button:hover {
    background: #1976D2;
    transform: translate(-2px, -2px);
    box-shadow: 4px 4px 0px 0px #000000;
}

.string-button.active {
    background: #E53935;
    transform: translate(-2px, -2px);
    box-shadow: 4px 4px 0px 0px #000000;
}

.string-name {
    font-size: 1.3em;
    font-weight: bold;
}

.string-octave {
    font-size: 0.8em;
    opacity: 0.9;
}

.detected-string {
    text-align: center;
    padding: 14px;
    background: #FFFFFF;
    border: 4px solid #000000;
    border-radius: 0;
    font-size: 1.15em;
    font-weight: 900;
    text-transform: uppercase;
    letter-spacing: 2px;
}

#detectedStringName {
    color: #000000;
    margin-right: 10px;
}

.tuning-status {
    font-size: 0.9em;
    padding: 8px 16px;
    border: 3px solid #000000;
    border-radius: 0;
    display: inline-block;
    font-weight: 900;
    text-transform: uppercase;
    letter-spacing: 1px;
    transition: background 0.2s ease, color 0.2s ease;
}

.tuning-status.in-tune {
    background: #4CAF50;
    color: #FFFFFF;
    border-color: #000000;
}

.tuning-status.sharp {
    background: #FF9800;
    color: #000000;
    border-color: #000000;
}

.tuning-status.flat {
    background: #2196F3;
    color: #FFFFFF;
    border-color: #000000;
}

.controls {
    display: flex;
    gap: 15px;
    justify-content: center;
}

.btn {
    padding: 14px 24px;
    border: 3px solid #000000;
    border-radius: 0;
    font-size: 1.1em;
    font-weight: 900;
    cursor: pointer;
    transition: all 0.2s ease;
    flex: 1;
    max-width: 200px;
    text-transform: uppercase;
    letter-spacing: 2px;
}

.btn-primary {
    background: #E53935;
    color: #FFFFFF;
}

.btn-primary:hover:not(:disabled) {
    background: #C62828;
    transform: translate(-2px, -2px);
    box-shadow: 4px 4px 0px 0px #000000;
}

.btn-secondary {
    background: #000000;
    color: #FFFFFF;
}

.btn-secondary:hover:not(:disabled) {
    background: #424242;
    transform: translate(-2px, -2px);
    box-shadow: 4px 4px 0px 0px #000000;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.banner-link {
    display: block;
    margin-top: 20px;
    padding: 12px 20px;
    text-align: center;
    background: #FFEB3B;
    color: #000000;
    text-decoration: none;
    font-weight: 900;
    text-transform: uppercase;
    letter-spacing: 2px;
    border: 3px solid #000000;
    transition: all 0.2s ease;
}

.banner-link:hover {
    background: #E53935;
    color: #FFFFFF;
    transform: translate(-2px, -2px);
    box-shadow: 4px 4px 0px 0px #000000;
}

@media (max-width: 480px) {
    body {
        padding: 8px;
        padding: max(8px, env(safe-area-inset-top)) max(8px, env(safe-area-inset-right)) max(8px, env(safe-area-inset-bottom)) max(8px, env(safe-area-inset-left));
        align-items: flex-start;
        padding-top: max(12px, env(safe-area-inset-top));
    }

    .container {
        padding: 16px;
        border-width: 4px;
        box-shadow: 6px 6px 0px 0px #000000;
    }

    .tuner-container {
        gap: 14px;
    }

    .frequency-display {
        padding: 16px 12px;
    }

    .frequency-value {
        font-size: 2.2em;
    }

    .note-display {
        font-size: 1.6em;
    }

    .tuning-meter {
        height: 80px;
        margin: 12px 0;
    }

    .meter-scale {
        padding: 0 12px;
    }

    .scale-mark {
        font-size: 0.75em;
    }

    .string-selector {
        grid-template-columns: repeat(6, 1fr);
        gap: 6px;
    }

    .string-button {
        padding: 10px 4px;
        min-height: 44px;
    }

    .string-name {
        font-size: 1.1em;
    }

    .detected-string {
        padding: 12px;
        font-size: 1em;
    }

    .tuning-status {
        font-size: 0.8em;
        padding: 6px 12px;
    }

    .controls {
        gap: 10px;
    }

    .btn {
        padding: 14px 20px;
        min-height: 48px;
        font-size: 1em;
    }

    .banner-link {
        margin-top: 16px;
        padding: 12px 16px;
        font-size: 0.95em;
    }
}

.content-section {
    margin-top: 50px;
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.content-block {
    background: #FFFFFF;
    border: 4px solid #000000;
    border-radius: 0;
    padding: 30px;
    box-shadow: 6px 6px 0px 0px #000000;
}

.content-block h2 {
    font-size: 2em;
    color: #000000;
    margin-bottom: 20px;
    font-weight: 900;
    text-transform: uppercase;
    letter-spacing: -1px;
    border-bottom: 3px solid #000000;
    padding-bottom: 15px;
}

.content-block h3 {
    font-size: 1.4em;
    color: #000000;
    margin-top: 25px;
    margin-bottom: 12px;
    font-weight: 900;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.content-block p {
    font-size: 1.1em;
    line-height: 1.8;
    color: #000000;
    margin-bottom: 15px;
    font-weight: 400;
}

.content-block a {
    color: #E53935;
    font-weight: 900;
    text-decoration: none;
}

.content-block a:hover {
    text-decoration: underline;
}

.content-block ul.tuning-list {
    list-style: none;
    padding-left: 0;
    margin: 20px 0;
}

.content-block ul.tuning-list li {
    font-size: 1.05em;
    line-height: 1.8;
    color: #000000;
    margin-bottom: 12px;
    padding-left: 25px;
    position: relative;
    font-weight: 400;
}

.content-block ul.tuning-list li::before {
    content: '•';
    position: absolute;
    left: 0;
    font-size: 1.5em;
    color: #E53935;
    font-weight: 900;
    line-height: 1.2;
}

.content-block ul.tuning-list li strong {
    color: #000000;
    font-weight: 900;
    text-transform: uppercase;
}

.page-title {
    font-size: 2.5em;
    color: #000000;
    margin-bottom: 15px;
    font-weight: 900;
    text-transform: uppercase;
    letter-spacing: -1px;
}

.page-subtitle {
    font-size: 1.1em;
    color: #000000;
    margin-bottom: 30px;
    font-weight: 400;
    line-height: 1.6;
}

@media (max-width: 600px) {
    .container {
        padding: 20px;
    }

    .frequency-value {
        font-size: 2em;
    }

    .note-display {
        font-size: 1.5em;
    }

    .string-selector {
        grid-template-columns: repeat(3, 1fr);
    }

    .content-block {
        padding: 20px;
    }

    .content-block h2 {
        font-size: 1.5em;
    }

    .content-block h3 {
        font-size: 1.2em;
    }

    .content-block p {
        font-size: 1em;
    }

    .content-block ul.tuning-list li {
        font-size: 0.95em;
    }

    .page-title {
        font-size: 1.8em;
    }
}