アコーディオン：吹き出し風｜Accordion: Speech Bubble

<div class="container">
    <div class="btn-box">
        <button data-default-text="Speech Bubble Accordion" data-open-text="Close">Speech Bubble Accordion</button>
    </div>
    <div class="more">
        <ul>
            <li>Speech bubble design</li>
            <li>Rounded corners with tail</li>
            <li>Light blue color scheme</li>
            <li>Chat message appearance</li>
            <li>Friendly and approachable</li>
        </ul>
    </div>
</div>

@keyframes speechBubbleFadeIn {
    0% {
        opacity: 0;
        transform: translateY(-8px) scale(0.95);
    }
    100% {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

.container {
    margin: 25px 0;
    position: relative;
}

.container .btn-box button {
    width: 100%;
    padding: 18px 25px;
    background: #f0f8ff;
    border: 2px solid #87ceeb;
    border-radius: 20px 20px 20px 20px;
    font-size: 16px;
    font-weight: 500;
    color: #4682b4;
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: left;
    position: relative;
    font-family: 'Arial', sans-serif;
    box-shadow: 0 2px 8px rgba(135, 206, 235, 0.3);
}

.container .btn-box button::before {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 20px;
    width: 0;
    height: 0;
    border-left: 8px solid transparent;
    border-right: 8px solid transparent;
    border-top: 8px solid #87ceeb;
}

.container .btn-box button::after {
    content: '▼';
    position: absolute;
    right: 20px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 12px;
    color: #4682b4;
    transition: transform 0.3s ease;
}

.container .btn-box button:hover {
    background: #e6f3ff;
    border-color: #5f9ea0;
    color: #2e8b57;
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(135, 206, 235, 0.4);
}

.container .more {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.5s ease;
    background: #f0f8ff;
    border: none;
    box-shadow: none;
    margin-top: 8px;
    position: relative;
}

.container .more::before {
    content: '';
    position: absolute;
    top: -8px;
    left: 20px;
    width: 0;
    height: 0;
    border-left: 8px solid transparent;
    border-right: 8px solid transparent;
    border-bottom: 8px solid #87ceeb;
}

.container .more.appear {
    max-height: 500px;
    animation: speechBubbleFadeIn 0.4s ease;
    border: 2px solid #87ceeb;
    box-shadow: 0 2px 8px rgba(135, 206, 235, 0.3);
}

.container:has(.more.appear) .btn-box button::after {
    transform: translateY(-50%) rotate(180deg);
}

.container .more ul {
    list-style: none;
    padding: 25px 25px 20px;
    margin: 0;
}

.container .more li {
    padding: 10px 0;
    color: #4682b4;
    font-size: 15px;
    line-height: 1.6;
    border-bottom: 1px solid rgba(135, 206, 235, 0.3);
    position: relative;
    padding-left: 15px;
}

.container .more li:hover {
    color: #2e8b57;
    padding-left: 20px;
}

.container .more li:last-child {
    border-bottom: none;
}

/* レスポンシブ対応 */
@media (max-width: 768px) {
    .container .btn-box button {
        font-size: 14px;
        padding: 15px 20px;
        border-radius: 15px 15px 15px 5px;
    }
    
    .container .more {
        border-radius: 15px 15px 15px 5px;
    }
    
    .container .more ul {
        padding: 20px 20px 15px;
    }
    
    .container .more.appear {
        max-height: 400px;
    }
}

// Add event listeners to all accordion buttons
document.addEventListener('DOMContentLoaded', function() {
    const accordionButtons = document.querySelectorAll('.btn-box button');
    
    accordionButtons.forEach(button => {
        button.addEventListener('click', function() {
            const container = this.closest('.container');
            const more = container.querySelector('.more');
            const isOpen = more.classList.contains('appear');
                        
            more.classList.toggle('appear');
            
            // Change button text
            if (this.dataset.defaultText) {
                if (isOpen) {
                    this.textContent = this.dataset.defaultText;
                } else {
                    this.textContent = this.dataset.openText || 'Close';
                }
            }
        });
    });
});