body {
    background-color: #000000;
    color: #fff;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    margin: 0;
    padding: 0;
}

.theory-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 20px;
    background-color: #0a0a0a;
    min-height: 100vh;
}

.theory-header {
    text-align: center;
    margin-bottom: 50px;
    padding: 50px 40px;
    background: linear-gradient(135deg, #1AB04E 0%, #13823b 100%);
    color: #000;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(26, 176, 78, 0.3);
}

.theory-header h1 {
    font-size: 3em;
    margin: 0 0 15px 0;
    font-weight: 800;
}

.theory-header p {
    font-size: 1.2em;
    opacity: 0.9;
    font-weight: 500;
    margin: 0;
}


.theory-tabs {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 40px;
    background: #1a1a1a;
    padding: 10px;
    border-radius: 15px;
    border: 1px solid #2a2a2a;
}

.theory-tab {
    padding: 15px 35px;
    background: transparent;
    border: none;
    font-size: 1.1em;
    font-weight: 600;
    color: #666;
    cursor: pointer;
    transition: all 0.3s ease;
    border-radius: 10px;
}

.theory-tab:hover {
    color: #1AB04E;
    background: rgba(26, 176, 78, 0.1);
}

.theory-tab.active {
    color: #000;
    background: #1AB04E;
}


.theory-content {
    display: none;
    animation: fadeIn 0.5s ease;
}

.theory-content.active {
    display: block;
}

@keyframes fadeIn {
    from { 
        opacity: 0; 
        transform: translateY(20px); 
    }
    to { 
        opacity: 1; 
        transform: translateY(0); 
    }
}


.section-title {
    color: #fff;
    font-size: 2em;
    margin-bottom: 30px;
    font-weight: 700;
}

.guitar-types {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
    margin-bottom: 50px;
}

.guitar-type-card {
    background: #1a1a1a;
    border-radius: 20px;
    padding: 30px;
    border: 2px solid #2a2a2a;
    transition: all 0.4s ease;
    position: relative;
    overflow: hidden;
}

.guitar-type-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, #1AB04E 0%, #13823b 100%);
    transform: scaleX(0);
    transition: transform 0.4s ease;
}

.guitar-type-card:hover::before {
    transform: scaleX(1);
}

.guitar-type-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 12px 30px rgba(26, 176, 78, 0.3);
    border-color: #1AB04E;
}

.guitar-type-card h3 {
    color: #1AB04E;
    margin-top: 0;
    margin-bottom: 18px;
    font-size: 1.6em;
    font-weight: 700;
}

.guitar-type-card p {
    color: #aaa;
    line-height: 1.7;
    margin: 0;
}

.guitar-parts {
    background: #1a1a1a;
    border-radius: 20px;
    padding: 40px;
    border: 2px solid #2a2a2a;
    margin-top: 30px;
}

.guitar-parts h2 {
    color: #fff;
    margin-bottom: 30px;
    font-size: 2em;
    font-weight: 700;
}

.parts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
}

.part-item {
    padding: 20px;
    background: #0f0f0f;
    border-radius: 12px;
    border-left: 4px solid #1AB04E;
    transition: all 0.3s ease;
}

.part-item:hover {
    background: #1a1a1a;
    transform: translateX(5px);
    box-shadow: 0 4px 15px rgba(26, 176, 78, 0.2);
}

.part-item h4 {
    color: #1AB04E;
    margin: 0 0 12px 0;
    font-size: 1.2em;
    font-weight: 700;
}

.part-item p {
    color: #aaa;
    margin: 0;
    line-height: 1.6;
}

.scales-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
    gap: 35px;
}

.scale-card {
    background: #1a1a1a;
    border-radius: 20px;
    padding: 35px;
    border: 2px solid #2a2a2a;
    transition: all 0.4s ease;
}

.scale-card:hover {
    border-color: #1AB04E;
    box-shadow: 0 10px 30px rgba(26, 176, 78, 0.2);
}

.scale-card h2 {
    color: #1AB04E;
    margin-top: 0;
    margin-bottom: 25px;
    font-size: 2em;
    font-weight: 700;
}

.scale-info {
    background: #0f0f0f;
    padding: 25px;
    border-radius: 15px;
    margin-bottom: 25px;
    border: 1px solid #2a2a2a;
}

.scale-info h3 {
    color: #fff;
    margin-top: 0;
    margin-bottom: 15px;
    font-weight: 700;
}

.scale-info p {
    color: #aaa;
    line-height: 1.7;
    margin-bottom: 15px;
}

.scale-formula {
    background: #1AB04E;
    color: #000;
    padding: 18px;
    border-radius: 12px;
    font-family: 'Courier New', monospace;
    font-size: 1.2em;
    font-weight: 800;
    text-align: center;
    margin: 20px 0;
    letter-spacing: 2px;
}

.scale-example {
    margin-top: 20px;
}

.scale-example strong {
    color: #1AB04E;
    font-weight: 700;
}

.scale-notes {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 15px;
}

.note-badge {
    background: #1AB04E;
    color: #000;
    padding: 10px 18px;
    border-radius: 25px;
    font-weight: 800;
    font-size: 1em;
}

.chords-intro {
    background: #1a1a1a;
    padding: 35px;
    border-radius: 20px;
    border: 2px solid #2a2a2a;
    margin-bottom: 40px;
}

.chords-intro h2 {
    color: #1AB04E;
    margin-top: 0;
    font-size: 2em;
    font-weight: 700;
}

.chords-intro p {
    color: #aaa;
    line-height: 1.7;
    margin-bottom: 15px;
}

.chords-intro ul {
    color: #aaa;
    line-height: 1.8;
}

.chords-intro ul li {
    margin-bottom: 10px;
}

.chords-intro strong {
    color: #fff;
}

.chords-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.chord-card {
    background: #1a1a1a;
    border-radius: 20px;
    padding: 30px;
    border: 2px solid #2a2a2a;
    text-align: center;
    transition: all 0.4s ease;
}

.chord-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px rgba(26, 176, 78, 0.3);
    border-color: #1AB04E;
}

.chord-name {
    font-size: 2.5em;
    font-weight: 800;
    color: #1AB04E;
    margin: 0 0 15px 0;
}

.chord-type {
    display: inline-block;
    background: #1AB04E;
    color: #000;
    padding: 6px 18px;
    border-radius: 20px;
    font-size: 0.9em;
    font-weight: 700;
    margin-bottom: 20px;
}

.chord-image {
    width: 100%;
    max-width: 220px;
    height: auto;
    margin: 20px auto;
    display: block;
    border-radius: 12px;
    background: #0f0f0f;
    padding: 15px;
    border: 1px solid #2a2a2a;
}

.chord-fingers {
    color: #888;
    font-size: 1em;
    margin-top: 15px;
    font-weight: 500;
}

@media (max-width: 768px) {
    .theory-container {
        padding: 20px 15px;
    }

    .theory-header {
        padding: 35px 25px;
    }
    
    .theory-header h1 {
        font-size: 2.2em;
    }

    .theory-header p {
        font-size: 1em;
    }
    
    .theory-tabs {
        flex-direction: column;
        gap: 10px;
    }
    
    .theory-tab {
        text-align: center;
        padding: 12px 20px;
    }
    
    .guitar-types,
    .scales-container,
    .chords-grid {
        grid-template-columns: 1fr;
    }
    
    .guitar-parts,
    .chords-intro {
        padding: 25px 20px;
    }
}