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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f5f5;
}

header {
    background-color: #fff;
    padding: 2rem 0;
    text-align: center;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    margin-bottom: 2rem;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 300;
    letter-spacing: 0.05em;
    color: #222;
}

main {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 1.5rem 3rem;
}

.expandable-list {
    list-style: none;
}

.list-item {
    background-color: #fff;
    margin-bottom: 1rem;
    border-radius: 4px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    transition: box-shadow 0.3s ease;
}

.list-item:hover {
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.15);
}

.item-header {
    padding: 1.25rem 1.5rem;
    font-size: 1.1rem;
    font-weight: 500;
    cursor: pointer;
    user-select: none;
    position: relative;
    transition: background-color 0.2s ease;
}

.item-header:hover {
    background-color: #f8f8f8;
}

.item-header::after {
    content: '+';
    position: absolute;
    right: 1.5rem;
    font-size: 1.5rem;
    font-weight: 300;
    transition: transform 0.3s ease;
    color: #666;
}

.list-item.active .item-header::after {
    transform: rotate(45deg);
}

.item-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding 0.4s ease;
    padding: 0 1.5rem;
}

.list-item.active .item-content {
    max-height: 500px;
    padding: 0 1.5rem 1.5rem;
}

.item-content p {
    color: #555;
    line-height: 1.7;
}

/* Highlighted list item style */
.list-item.highlighted {
    border-left: 4px solid #4a90e2;
    box-shadow: 0 2px 6px rgba(74, 144, 226, 0.15);
}

.list-item.highlighted .item-header {
    background-color: #f0f7ff;
    color: #2c5aa0;
}

.list-item.highlighted .item-header:hover {
    background-color: #e6f2ff;
}

.list-item.highlighted .item-content {
    background-color: #fafcff;
}

.list-item.highlighted .item-content p {
    color: #444;
}

.list-item.highlighted:hover {
    box-shadow: 0 3px 8px rgba(74, 144, 226, 0.2);
}

footer {
    background-color: #fff;
    padding: 2rem 0;
    text-align: center;
    box-shadow: 0 -2px 4px rgba(0, 0, 0, 0.1);
    margin-top: 3rem;
}

.bluesky-logo {
    height: 40px;
    width: auto;
    opacity: 0.7;
    transition: opacity 0.3s ease, transform 0.3s ease;
}

footer a {
    display: inline-block;
    text-decoration: none;
}

footer a:hover .bluesky-logo {
    opacity: 1;
    transform: scale(1.05);
}

@media (max-width: 600px) {
    header h1 {
        font-size: 2rem;
    }
    
    .item-header {
        padding: 1rem 1.25rem;
        font-size: 1rem;
    }
    
    .item-content {
        padding: 0 1.25rem;
    }
    
    .list-item.active .item-content {
        padding: 0 1.25rem 1.25rem;
    }
}