:root {
    --primary-color: #2563eb;
    --secondary-color: #64748b;
    --success-color: #22c55e;
    --error-color: #ef4444;
    --warning-color: #f59e0b;
    --background: #f8fafc;
    --card-background: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --white-key: #ffffff;
    --black-key: #1e293b;
    --key-pressed: #3b82f6;
    --key-correct: #22c55e;
    --key-incorrect: #ef4444;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 2px solid var(--border-color);
}

h1 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
}

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

.status-indicator {
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 500;
    background: var(--secondary-color);
    color: white;
}

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

.card {
    background: var(--card-background);
    border-radius: 12px;
    padding: 24px;
    margin-bottom: 20px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.card h2 {
    font-size: 1.5rem;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.btn {
    padding: 10px 20px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

.btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.btn-primary {
    background: var(--primary-color);
    color: white;
}

.btn-secondary {
    background: var(--secondary-color);
    color: white;
}

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

select {
    width: auto;
    min-width: 200px;
    padding: 10px;
    margin-top: 10px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    background: white;
}

.hidden {
    display: none !important;
}

/* Back Button - Override for text-only style */
.back-button-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: flex-start;
    padding: 20px;
}

.back-btn {
    padding: 8px 15px;
    border: none;
    border-radius: 0;
    background: transparent;
    color: var(--text-secondary);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    box-shadow: none;
}

.back-btn:hover {
    color: var(--text-primary);
    transform: none;
    box-shadow: none;
}

/* Exercise Selection */
.exercise-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.exercise-btn {
    padding: 20px;
    background: var(--background);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.2s;
    text-align: left;
}

.exercise-btn:hover {
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.2);
}

.exercise-btn h3 {
    font-size: 1.125rem;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.exercise-btn p {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Exercise Area */
.exercise-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
}

.prompt-area {
    text-align: center;
    margin: 20px 0;
}

.prompt {
    font-size: 2rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 10px;
    min-height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    border-radius: 8px;
    padding: 8px 16px;
    transition: background-color 0.2s ease;
}

.prompt:hover {
    background-color: rgba(59, 130, 246, 0.08);
}

.feedback {
    font-size: 1.1rem;
    font-weight: 500;
    min-height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: opacity 0.3s ease;
    position: relative;
}

.feedback.correct {
    color: var(--success-color);
    font-size: 1.5rem;
}

.feedback.incorrect {
    color: var(--error-color);
}

.controls {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin: 15px 0;
}

.stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 20px;
    margin-top: 40px;
    padding-top: 30px;
    border-top: 2px solid var(--border-color);
}

.sessions-stats {
    display: flex;
    justify-content: space-around;
    gap: 20px;
    margin-bottom: 30px;
}

.stat {
    text-align: center;
}

.stat-label {
    display: block;
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 4px;
}

.stat span:last-child {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

/* Visual Keyboard */
.keyboard {
    display: flex;
    justify-content: center;
    padding: 30px;
    background: var(--background);
    border-radius: 12px;
    margin-top: 10px;
    overflow-x: auto;
    max-width: 100%;
}

/* Keyboard scaling for different container widths */
.keyboard-scale-medium .key.white {
    width: 32px;
    height: 120px;
}

.keyboard-scale-medium .key.black {
    width: 22px;
    height: 80px;
}

.keyboard-scale-small .key.white {
    width: 26px;
    height: 100px;
}

.keyboard-scale-small .key.black {
    width: 18px;
    height: 65px;
}

.keyboard-scale-tiny .key.white {
    width: 22px;
    height: 85px;
}

.keyboard-scale-tiny .key.black {
    width: 15px;
    height: 55px;
}

.keyboard-octave {
    display: flex;
    position: relative;
}

.key {
    position: relative;
    cursor: pointer;
    transition: all 0.1s;
    user-select: none;
}

.key.white {
    width: 40px;
    height: 150px;
    background: var(--white-key);
    border: 1px solid var(--border-color);
    border-radius: 0 0 4px 4px;
}

.key.black {
    width: 28px;
    height: 100px;
    background: var(--black-key);
    border-radius: 0 0 3px 3px;
    position: absolute;
    z-index: 2;
}

.key:hover {
    background: var(--border-color);
}

.key.pressed {
    background: var(--key-pressed) !important;
    transform: translateY(2px);
    box-shadow: 0 0 10px rgba(59, 130, 246, 0.5);
}

.key.correct {
    background: var(--key-correct) !important;
    animation: correctPulse 0.5s ease;
}

.key.incorrect {
    background: var(--key-incorrect) !important;
    animation: incorrectShake 0.3s ease;
}

@keyframes correctPulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.1); box-shadow: 0 0 20px rgba(34, 197, 94, 0.7); }
    100% { transform: scale(1); }
}

@keyframes incorrectShake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

.key-label {
    position: absolute;
    bottom: 10px;
    width: 100%;
    text-align: center;
    font-size: 0.75rem;
    font-weight: 500;
    pointer-events: none;
}

.key.white .key-label {
    color: var(--text-primary);
}

.key.black .key-label {
    color: white;
    bottom: 5px;
}

.note-name {
    display: block;
    font-weight: 600;
    line-height: 1;
}

.octave-number {
    display: block;
    font-size: 0.6rem;
    opacity: 0.4;
    line-height: 1;
    margin-top: 1px;
}

.key.black .octave-number {
    opacity: 0.5;
}

/* Black key positions - default */
.key.black[data-note*="C#"] { left: 28px; }
.key.black[data-note*="D#"] { left: 68px; }
.key.black[data-note*="F#"] { left: 148px; }
.key.black[data-note*="G#"] { left: 188px; }
.key.black[data-note*="A#"] { left: 228px; }

/* Black key positions - medium scale */
.keyboard-scale-medium .key.black[data-note*="C#"] { left: 21px; }
.keyboard-scale-medium .key.black[data-note*="D#"] { left: 53px; }
.keyboard-scale-medium .key.black[data-note*="F#"] { left: 117px; }
.keyboard-scale-medium .key.black[data-note*="G#"] { left: 149px; }
.keyboard-scale-medium .key.black[data-note*="A#"] { left: 181px; }

/* Black key positions - small scale */
.keyboard-scale-small .key.black[data-note*="C#"] { left: 17px; }
.keyboard-scale-small .key.black[data-note*="D#"] { left: 43px; }
.keyboard-scale-small .key.black[data-note*="F#"] { left: 95px; }
.keyboard-scale-small .key.black[data-note*="G#"] { left: 121px; }
.keyboard-scale-small .key.black[data-note*="A#"] { left: 147px; }

/* Black key positions - tiny scale */
.keyboard-scale-tiny .key.black[data-note*="C#"] { left: 15px; }
.keyboard-scale-tiny .key.black[data-note*="D#"] { left: 37px; }
.keyboard-scale-tiny .key.black[data-note*="F#"] { left: 81px; }
.keyboard-scale-tiny .key.black[data-note*="G#"] { left: 103px; }
.keyboard-scale-tiny .key.black[data-note*="A#"] { left: 125px; }

/* Settings Panel */
.settings-panel {
    background: var(--background);
    border-radius: 8px;
    padding: 20px;
    margin: 20px 0;
    border: 1px solid var(--border-color);
}

.settings-panel h4 {
    margin-top: 0;
    margin-bottom: 15px;
    color: var(--primary-color);
}

.setting-group {
    margin-bottom: 15px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.setting-group label {
    min-width: 120px;
    font-weight: 500;
    color: var(--text-secondary);
}

.setting-group select {
    flex: 1;
    max-width: 250px;
    padding: 8px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
}

.setting-group input[type="checkbox"] {
    width: 20px;
    height: 20px;
    cursor: pointer;
}

.checkbox-label {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.position-info {
    font-size: 1.125rem;
    color: var(--primary-color);
    margin-top: 10px;
    font-weight: 500;
}

/* MIDI Test Mode */
#midi-test-area {
    margin-top: 20px;
    padding-top: 20px;
    border-top: 2px solid var(--border-color);
}

#midi-test-area h3 {
    font-size: 1.25rem;
    margin-bottom: 10px;
    color: var(--primary-color);
}

#test-output {
    background: var(--background);
    border-radius: 8px;
    padding: 20px;
    margin: 20px 0;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
}

.test-display {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 10px;
    background: white;
    border-radius: 6px;
    border: 1px solid var(--border-color);
}

.test-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 5px;
}

.test-value {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.test-value.active {
    color: var(--success-color);
    animation: pulse 0.3s ease;
}

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

/* Microphone Tuner */
.microphone-tuner {
    background: var(--background);
    border-radius: 12px;
    padding: 30px;
    margin-top: 20px;
    text-align: center;
}

.microphone-tuner h3 {
    font-size: 1.25rem;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.tuner-display {
    max-width: 400px;
    margin: 0 auto;
}

.detected-note {
    font-size: 3rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 10px;
    min-height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.frequency-display {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 20px;
}

.cents-meter {
    position: relative;
    height: 40px;
    background: var(--border-color);
    border-radius: 20px;
    margin: 20px 0;
    overflow: hidden;
}

.cents-scale {
    display: flex;
    justify-content: space-between;
    padding: 0 20px;
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 100%;
    font-size: 0.75rem;
    color: var(--text-secondary);
    z-index: 2;
}

.cents-indicator {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translateX(-50%) translateY(-50%);
    width: 4px;
    height: 30px;
    background: var(--primary-color);
    border-radius: 2px;
    transition: left 0.2s ease;
    z-index: 3;
}

.cents-indicator.in-tune {
    background: var(--success-color);
}

.cents-indicator.out-of-tune {
    background: var(--error-color);
}

.tuning-status {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-top: 15px;
}

.tuning-status.in-tune {
    color: var(--success-color);
    font-weight: 600;
}

/* Configuration Section */
.config-section {
    margin-top: 30px;
    padding-top: 30px;
    border-top: 2px solid var(--border-color);
}

.config-section h3 {
    font-size: 1.25rem;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.config-group {
    margin-bottom: 20px;
}

.config-group-row {
    display: flex;
    gap: 40px;
    margin-bottom: 20px;
}

.config-group-row .config-group {
    margin-bottom: 0;
    flex: 1;
}

.config-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 10px;
}

.button-group {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.config-btn {
    padding: 12px 20px;
    border: 3px solid #e2e8f0;
    border-radius: 8px;
    background: #f8fafc;
    color: #94a3b8;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.config-btn:hover {
    border-color: #2563eb;
    transform: translateY(-1px);
}

.config-btn.active {
    background: #2563eb;
    color: white;
    border-color: #2563eb;
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

/* Responsive */
@media (max-width: 768px) {
    .container {
        padding: 10px;
    }

    h1 {
        font-size: 1.5rem;
    }

    .prompt {
        font-size: 2rem;
    }

    .key.white {
        width: 30px;
        height: 120px;
    }

    .key.black {
        width: 20px;
        height: 80px;
    }

    .key.black[data-note*="C#"] { left: 20px; }
    .key.black[data-note*="D#"] { left: 50px; }
    .key.black[data-note*="F#"] { left: 110px; }
    .key.black[data-note*="G#"] { left: 140px; }
    .key.black[data-note*="A#"] { left: 170px; }
}

/* Text Input Answer Mode */
.text-input {
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 20px 0;
    padding: 20px;
}

.note-input {
    width: 300px;
    padding: 15px 20px;
    font-size: 1.5rem;
    font-weight: 600;
    text-align: center;
    border: 3px solid var(--border-color);
    border-radius: 12px;
    background: var(--card-background);
    color: var(--text-primary);
    outline: none;
    transition: all 0.2s ease;
    text-transform: uppercase;
}

.note-input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.note-input.correct {
    border-color: var(--success-color);
    background-color: rgba(34, 197, 94, 0.1);
    color: var(--success-color);
}

.note-input.incorrect {
    border-color: var(--error-color);
    background-color: rgba(239, 68, 68, 0.1);
    color: var(--error-color);
}

.note-input::placeholder {
    color: var(--text-secondary);
    font-weight: 400;
    text-transform: none;
}

/* Interval Answer Mode */
.interval-answer {
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 20px 0;
    padding: 20px;
}

.interval-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
    max-width: 800px;
}

.interval-btn {
    padding: 12px 20px;
    font-size: 1rem;
    font-weight: 600;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background: var(--card-background);
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.2s ease;
    min-width: 80px;
    text-align: center;
}

.interval-btn:hover {
    border-color: var(--primary-color);
    background: rgba(37, 99, 235, 0.1);
    transform: translateY(-1px);
}

.interval-btn:active {
    transform: translateY(0);
}

.interval-btn.correct {
    border-color: var(--success-color);
    background: rgba(34, 197, 94, 0.1);
    color: var(--success-color);
}

.interval-btn.incorrect {
    border-color: var(--error-color);
    background: rgba(239, 68, 68, 0.1);
    color: var(--error-color);
}

/* Results Section */
.results-section {
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

.results-section h3 {
    font-size: 1.25rem;
    margin-bottom: 20px;
    color: var(--text-primary);
    text-align: left;
}

.chart-container {
    position: relative;
    width: 100%;
    margin: 0 auto;
    background: var(--background);
    border-radius: 8px;
    padding: 20px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.chart-container canvas {
    max-width: 100%;
    height: auto !important;
}

/* Practice Sessions */
.sessions-summary {
    display: flex;
    gap: 30px;
    margin-bottom: 25px;
    justify-content: center;
}

.summary-stat {
    text-align: center;
    padding: 15px;
    background: var(--background);
    border-radius: 8px;
    border: 1px solid var(--border-color);
    min-width: 80px;
}

.stat-value {
    display: block;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 5px;
}

.stat-label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.sessions-table-container {
    overflow-x: auto;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.sessions-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
}

.sessions-table th {
    background: var(--background);
    padding: 12px 15px;
    text-align: left;
    font-weight: 600;
    color: var(--text-primary);
    border-bottom: 2px solid var(--border-color);
}

.sessions-table td {
    padding: 12px 15px;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-primary);
}

.sessions-table tr:hover {
    background: rgba(0, 0, 0, 0.02);
}

.sessions-table tr.no-sessions td {
    text-align: center;
    color: var(--text-secondary);
    font-style: italic;
    padding: 30px;
}

.sessions-table .accuracy-good {
    color: var(--success-color);
    font-weight: 600;
}

.sessions-table .accuracy-fair {
    color: #f59e0b;
    font-weight: 600;
}

.sessions-table .accuracy-poor {
    color: var(--error-color);
    font-weight: 600;
}

@media (max-width: 768px) {
    .sessions-summary {
        flex-direction: column;
        gap: 15px;
    }

    .sessions-table {
        font-size: 0.8rem;
    }

    .sessions-table th,
    .sessions-table td {
        padding: 8px 10px;
    }
}