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

        body {
            font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
            background: linear-gradient(135deg, #667eea, #764ba2);
            min-height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
            padding: 20px;
        }

        .container {
            background: white;
            border-radius: 20px;
            padding: 30px 40px;
            box-shadow: 0 20px 60px rgba(0, 0, 0, .3);
            max-width: 900px;
            width: 100%;
        }

        h1 {
            text-align: center;
            margin-bottom: 25px;
        }

        .mode-switch {
            display: flex;
            justify-content: center;
            gap: 10px;
            margin-bottom: 20px;
        }

        .mode-btn {
            padding: 10px 20px;
            border-radius: 10px;
            border: 2px solid #667eea;
            background: white;
            color: #667eea;
            font-weight: 600;
            cursor: pointer;
            transition: .15s;
        }

        .mode-btn.active {
            background: #667eea;
            color: white;
        }

        .stats {
            display: flex;
            justify-content: space-around;
            padding: 15px;
            margin-bottom: 25px;
            background: #f5f5f5;
            border-radius: 10px;
        }

        .stat {
            text-align: center;
        }

        .stat-value {
            font-size: 28px;
            font-weight: 700;
            margin-bottom: 4px;
        }

        .total {
            color: #667eea;
        }

        .correct {
            color: #10b981;
        }

        .incorrect {
            color: #ef4444;
        }

        .staff-container {
            position: relative;
            height: 260px;
            margin: 30px 0;
            background: white;
        }

        .clef {
            position: absolute;
            left: 80px;
            top: 50%;
            transform: translateY(-57%);
            font-size: 130px;
            line-height: 1;
            z-index: 2;
        }

        .staff-lines {
            position: absolute;
            left: 80px;
            right: 40px;
            top: 50%;
            transform: translateY(-50%);
        }

        .staff-line {
            width: 100%;
            height: 2px;
            background: #333;
            margin: 14px 0;
        }

        .note-symbol {
            position: absolute;
            left: 50%;
            transform: translateX(-50%);
            font-size: 20px;
            z-index: 3;
            transition: transform .2s;
        }

        .ledger-line {
            position: absolute;
            left: 50%;
            width: 55px;
            height: 2px;
            background: #333;
            transform: translateX(-50%);
            z-index: 2;
        }

        .feedback {
            text-align: center;
            min-height: 32px;
            font-size: 22px;
            font-weight: 600;
            margin: 10px 0 20px;
        }

        .feedback.correct {
            color: #10b981;
        }

        .feedback.incorrect {
            color: #ef4444;
        }

        .keyboard {
            display: flex;
            flex-direction: column;
            gap: 10px;
            align-items: center;
        }

        .octave-row {
            display: flex;
            gap: 10px;
            padding: 8px 12px;
            background: #f5f5f5;
            border-radius: 10px;
            align-items: center;
            flex-wrap: wrap;
        }

        .octave-label {
            font-weight: 600;
            color: #667eea;
            margin-right: 4px;
        }

        .key {
            padding: 10px 18px;
            border-radius: 10px;
            border: 2px solid #667eea;
            background: white;
            color: #667eea;
            font-weight: 600;
            cursor: pointer;
            transition: .15s;
            min-width: 45px;
            text-align: center;
        }

        .key:hover {
            background: #667eea;
            color: white;
            transform: translateY(-1px);
            box-shadow: 0 4px 10px rgba(102, 126, 234, .3);
        }

        .instructions {
            margin-top: 15px;
            text-align: center;
            font-size: 13px;
            color: #555;
        }

        .debug-panel {
            background: #fff3cd;
            border: 2px solid #ffc107;
            border-radius: 10px;
            padding: 20px;
            margin-bottom: 20px;
        }

        .debug-panel h3 {
            margin-bottom: 15px;
            color: #856404;
        }

        .debug-info {
            background: white;
            padding: 10px;
            border-radius: 5px;
            margin-top: 10px;
            font-family: monospace;
            font-size: 14px;
        }

        @keyframes shake {

            0%,
            100% {
                transform: translateX(-50%) translateY(0);
            }

            25% {
                transform: translateX(-48%) translateY(0);
            }

            75% {
                transform: translateX(-52%) translateY(0);
            }
        }

        .note-symbol.shake {
            animation: shake .35s;
        }

        @keyframes pulse {

            0%,
            100% {
                transform: translateX(-50%) scale(1);
            }

            50% {
                transform: translateX(-50%) scale(1.12);
            }
        }

        .note-symbol.pulse {
            animation: pulse .35s;
        }

        /* SRS Statistiky */
.srs-stats {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 20px;
    border-radius: 12px;
    margin: 20px 0;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
}

.srs-stats strong {
    font-size: 16px;
    display: block;
    margin-bottom: 12px;
    text-align: center;
}

.srs-progress {
    display: flex;
    justify-content: space-around;
    gap: 15px;
    flex-wrap: wrap;
}

.srs-item {
    flex: 1;
    min-width: 120px;
    background: rgba(255, 255, 255, 0.15);
    padding: 12px;
    border-radius: 8px;
    text-align: center;
    backdrop-filter: blur(10px);
}

.srs-item-value {
    font-size: 28px;
    font-weight: bold;
    margin-bottom: 5px;
}

.srs-item-label {
    font-size: 13px;
    opacity: 0.9;
}

/* Detailní statistiky v debug módu */
.detailed-stats {
    margin-top: 20px;
    background: #f8f9fa;
    padding: 15px;
    border-radius: 8px;
    max-height: 400px;
    overflow-y: auto;
}

.detailed-stats table {
    width: 100%;
    border-collapse: collapse;
    font-size: 13px;
}

.detailed-stats th {
    background: #667eea;
    color: white;
    padding: 8px;
    text-align: left;
    position: sticky;
    top: 0;
}

.detailed-stats td {
    padding: 6px 8px;
    border-bottom: 1px solid #e0e0e0;
}

.detailed-stats tr:hover {
    background: #f0f0f0;
}

/* Instructions */
.instructions {
    text-align: center;
    color: #666;
    font-size: 14px;
    margin-top: 15px;
    padding: 10px;
    background: #f8f9fa;
    border-radius: 8px;
}