ポップアップウィンドウ：ミニマル｜Pop-up Window: Minimal

<div class="container">
    <button id="popup-btn">Minimal</button>
    
    <div id="popup" class="popup">
        <div class="popup-content">
            <p>Minimal Popup</p>
            <p>A simple and minimal design popup window.</p>
        </div>
    </div>
</div>

body {
    font-family: Arial, sans-serif;
    padding: 20px;
    background: #f5f5f5;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

#popup-btn {
    cursor: pointer;
    border: none;
    padding: 12px 24px;
    border-radius: 16px;
    color: #333;
    background-color: #eee;
    font-weight: 600;
    box-shadow: 0 0 4px rgba(0, 0, 0, 0.3);
    display: block;
    margin: 0 auto;
    width: 180px;
}

#popup-btn:hover {
    opacity: 0.5;
}

.popup {
    position: fixed;
    bottom: -100%;
    left: 50%;
    transform: translateX(-50%);
    z-index: 1001;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    max-width: 90%;
    max-height: 90%;
}

.popup.active {
    opacity: 1;
    visibility: visible;
    bottom: 20px;
    transform: translateX(-50%);
    animation: popupShowHide 3.4s ease forwards;
}

@keyframes popupShowHide {
    0% {
        opacity: 0;
        transform: translateX(-50%) translateY(100%);
    }
    20% {
        opacity: 1;
        transform: translateX(-50%) translateY(0);
    }
    80% {
        opacity: 1;
        transform: translateX(-50%) translateY(0);
    }
    100% {
        opacity: 0;
        transform: translateX(-50%) translateY(100%);
    }
}

.popup-content {
    background: #ffffff;
    padding: 25px;
    border-radius: 4px;
    text-align: center;
    position: relative;
    min-width: 300px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    border: 1px solid #e9ecef;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

.popup-content p:first-child {
    font-size: 18px;
    font-weight: 400;
    margin-bottom: 15px;
    color: #495057;
    letter-spacing: 0.5px;
}

.popup-content p:last-of-type {
    font-size: 14px;
    color: #868e96;
    margin-bottom: 25px;
    line-height: 1.5;
    font-weight: 300;
}

/* レスポンシブ対応 */
@media (max-width: 768px) {
    .popup-content {
        padding: 20px;
        min-width: 280px;
    }
    
    .popup-content p:first-child {
        font-size: 16px;
    }
    
    .popup-content p:last-of-type {
        font-size: 13px;
    }
    
    #popup-btn {
        padding: 10px 20px;
        font-size: 14px;
    }
}

@media (max-width: 480px) {
    .popup-content {
        padding: 15px;
        min-width: 250px;
    }
    
    .popup-content p:first-child {
        font-size: 15px;
    }
    
    .popup-content p:last-of-type {
        font-size: 12px;
    }
    
    #popup-btn {
        padding: 8px 16px;
        font-size: 13px;
    }
}

document.addEventListener('DOMContentLoaded', function() {
    const popupBtn = document.getElementById('popup-btn');
    const popup = document.getElementById('popup');
    
    popupBtn.addEventListener('click', function() {
        popup.classList.add('active');
    });

    popup.addEventListener('animationend', function() {
        popup.classList.remove('active');
    });
});