モーダルウィンドウ：ウォーターカラー｜Modal Window: Water Color

<div class="container">
    <button class="modal-button">Watercolor Modal</button>

    <div class="mask"></div>
    <div class="modal">
        <button class="close-btn">Close</button>
        <div class="modal-content">
            <p>[Watercolor Modal]</p>
            <p>A modal window with soft watercolor effects and flowing color transitions. Features artistic brush strokes and gentle color blending for a creative, artistic appearance.</p>
        </div>
    </div>
</div>

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

.modal-button {
    padding: 15px 30px;
    background: linear-gradient(135deg, #E91E63 0%, #9C27B0 25%, #3F51B5 50%, #2196F3 75%, #00BCD4 100%);
    color: #fff;
    border: none;
    border-radius: 30px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(233, 30, 99, 0.3);
    position: relative;
    overflow: hidden;
}

.modal-button:hover {
    background: linear-gradient(135deg, #00BCD4 0%, #2196F3 25%, #3F51B5 50%, #9C27B0 75%, #E91E63 100%);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(233, 30, 99, 0.4);
}

.mask {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(233, 30, 99, 0.2);
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
}

.mask.appear {
    opacity: 1;
    visibility: visible;
}

.modal {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0.8);
    background: linear-gradient(135deg, #E3F2FD 0%, #BBDEFB 25%, #90CAF9 50%, #64B5F6 75%, #42A5F5 100%);
    padding: 40px;
    border-radius: 20px;
    z-index: 1001;
    opacity: 0;
    visibility: hidden;
    transition: all 0.4s cubic-bezier(0.68, -0.55, 0.27, 1.55);
    max-width: 500px;
    width: 90%;
    box-shadow: 0 15px 35px rgba(66, 165, 245, 0.2);
    border: 2px solid #2196F3;
    overflow: hidden;
}

.modal::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background:
        radial-gradient(circle at 20% 20%, rgba(33, 150, 243, 0.3) 0%, transparent 60%),
        radial-gradient(circle at 80% 80%, rgba(100, 181, 246, 0.2) 0%, transparent 70%),
        radial-gradient(circle at 40% 60%, rgba(144, 202, 249, 0.25) 0%, transparent 65%),
        radial-gradient(circle at 60% 30%, rgba(187, 222, 251, 0.2) 0%, transparent 55%);
    animation: watercolorFlow 12s ease-in-out infinite;
    pointer-events: none;
}

.modal::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background:
        linear-gradient(45deg, transparent 30%, rgba(255, 255, 255, 0.1) 50%, transparent 70%),
        linear-gradient(-45deg, transparent 40%, rgba(255, 255, 255, 0.05) 60%, transparent 80%);
    animation: watercolorShimmer 8s ease-in-out infinite;
    pointer-events: none;
}

.modal.appear {
    opacity: 1;
    visibility: visible;
    transform: translate(-50%, -50%) scale(1);
}

.modal p {
    color: #1565C0;
    font-weight: 600;
    text-align: center;
    margin-bottom: 24px;
    position: relative;
    z-index: 2;
    text-shadow: 0 1px 2px rgba(255, 255, 255, 0.5);
}

.close-btn {
    position: absolute;
    top: 15px;
    right: 15px;
    width: 32px;
    height: 32px;
    background: rgba(33, 150, 243, 0.9);
    color: #fff;
    border: none;
    border-radius: 50%;
    font-size: 18px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 15;
    line-height: 1;
}

.close-btn:hover {
    background: rgba(66, 165, 245, 0.9);
    transform: scale(1.1);
    box-shadow: 0 2px 8px rgba(33, 150, 243, 0.4);
}

@keyframes watercolorFlow {
    0%, 100% { transform: translate(0, 0) scale(1) rotate(0deg); opacity: 0.8; }
    25% { transform: translate(15px, -10px) scale(1.2) rotate(45deg); opacity: 1; }
    50% { transform: translate(-8px, 12px) scale(0.9) rotate(90deg); opacity: 0.6; }
    75% { transform: translate(-12px, -8px) scale(1.1) rotate(135deg); opacity: 0.9; }
}

@keyframes watercolorShimmer {
    0%, 100% { opacity: 0.3; transform: translateX(0) translateY(0); }
    25% { opacity: 0.6; transform: translateX(5px) translateY(-3px); }
    50% { opacity: 0.4; transform: translateX(-3px) translateY(5px); }
    75% { opacity: 0.7; transform: translateX(-5px) translateY(-2px); }
}

/* レスポンシブ対応 */
@media (max-width: 768px) {
    .modal {
        width: 95%;
        padding: 20px;
    }
                
    .modal p {
        font-size: 14px;
    }
    
    .modal-button {
        font-size: 14px;
        padding: 10px 20px;
    }
}

document.addEventListener('DOMContentLoaded', function() {
    const modalBtn = document.querySelector('.modal-button');
    const mask = document.querySelector('.mask');
    const modal = document.querySelector('.modal');
    const closeBtn = document.querySelector('.close-btn');
    
    // モーダルを開く
    modalBtn.addEventListener('click', () => {
        mask.classList.add('appear');
        modal.classList.add('appear');
    });
    
    // マスクをクリックして閉じる
    mask.addEventListener('click', () => {
        mask.classList.remove('appear');
        modal.classList.remove('appear');
    });
    
    // 閉じるボタンをクリックして閉じる
    closeBtn.addEventListener('click', () => {
        mask.classList.remove('appear');
        modal.classList.remove('appear');
    });
    
    // ESCキーで閉じる
    document.addEventListener('keydown', (e) => {
        if (e.key === 'Escape') {
            mask.classList.remove('appear');
            modal.classList.remove('appear');
        }
    });
});