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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: #e4e4e4;
    color: #333;
    line-height: 1.6;
}

#app-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    position: relative;
}

.view {
    width: 100%;
    text-align: center;
    padding: 20px;
    background: white;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    margin-bottom: 20px;
}

h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: #2c3e50;
}

p {
    margin-bottom: 2rem;
    color: #666;
}

.card-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 20px;
    margin: 2rem 0;
    padding: 0 20px;
}

.zener-card {
    aspect-ratio: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    background: white;
    border: 2px solid #e0e0e0;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.3s ease;
    user-select: none;
}

.zener-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.1);
    border-color: #3498db;
}

#secret-trigger-area {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    padding: 15px;
    text-align: center;
    font-size: 0.9rem;
    color: #666;
    cursor: pointer;
}


.config-controls {
    margin: 2rem 0;
}

input[type="range"] {
    width: 100%;
    max-width: 400px;
    margin: 1rem 0;
}

.checkbox-control {
    margin: 1rem 0;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.checkbox-control input[type="checkbox"] {
    width: 18px;
    height: 18px;
    margin: 0;
}

.button-group {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    max-width: 300px;
    margin: 0 auto;
}

button {
    padding: 12px 24px;
    font-size: 1rem;
    border: none;
    border-radius: 6px;
    background: #3498db;
    color: white;
    cursor: pointer;
    transition: background 0.3s ease;
}

button:hover {
    background: #2980b9;
}

#test-tone-btn {
    background: #2ecc71;
}

#test-tone-btn:hover {
    background: #27ae60;
}

#reset-code-btn {
    background: #e74c3c;
}

#reset-code-btn:hover {
    background: #c0392b;
}

#back-to-test-btn {
    background: #95a5a6;
}

#back-to-test-btn:hover {
    background: #7f8c8d;
}

.large-symbol {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 300px;
    margin: 2rem 0;
}

.large-symbol svg {
    max-width: 100%;
    height: auto;
}

@media (max-width: 600px) {
    .card-container {
        grid-template-columns: repeat(2, 1fr);
    }
    
    h1 {
        font-size: 2rem;
    }
    
    .zener-card {
        font-size: 2.5rem;
    }

    #secret-trigger-area {
        font-size: 0.8rem;
        padding: 10px;
    }
}