body {
    font-family: Arial, sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

header {
    background-color: #4CAF50;
    color: white;
    text-align: center;
    padding: 1rem;
}

header h1 {
    margin: 0;
}

main {
    flex: 1;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: auto;
    overflow: hidden;
    padding: 20px;
}

#sheetSelector {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 20px;
}

.sheet-button {
    padding: 10px 15px;
    font-size: 16px;
    background-color: #4CAF50;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s;
}

.sheet-button:hover {
    background-color: #45a049;
}

.sheet-button.active {
    background-color: #45a049;
    font-weight: bold;
}

#urlList {
    background: #fff;
    border-radius: 5px;
    padding: 20px;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
}

.url-item {
    margin-bottom: 10px;
    padding: 10px;
    background: #f9f9f9;
    border-radius: 3px;
}

.url-item a {
    color: #333;
    text-decoration: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.url-item a:hover {
    color: #0066cc;
}

.url-item h3 {
    margin: 0;
    font-size: 1.1em;
    color: #333;
}

footer {
    background-color: #333;
    color: white;
    text-align: center;
    padding: 1rem;
    margin-top: auto;
}

@media (max-width: 600px) {
    .sheet-button {
        width: 100%;
    }
    
    .url-item a {
        flex-direction: column;
        align-items: flex-start;
    }
}