タブメニュー：ネオンブルー｜Tab Menu: Neon Blue

<div class="container">
    <h1>Tab Design 8 - Neon Blue</h1>
    
    <div class="tab-container">
        <ul>
            <li class="selected" data-id="tab-1">Tab 1</li>
            <li data-id="tab-2">Tab 2</li>
            <li data-id="tab-3">Tab 3</li>
        </ul>
        <div class="tab-content selected" id="tab-1">
            Good morning. This is the content of Tab 1.
        </div>
        <div class="tab-content" id="tab-2">
            Hello. This is the content of Tab 2.
        </div>
        <div class="tab-content" id="tab-3">
            Good evening. This is the content of Tab 3.
        </div>
    </div>
</div>

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: #0a0a0a;
    padding: 20px;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background: #1a1a1a;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.5);
    overflow: hidden;
}

h1 {
    text-align: center;
    padding: 30px 20px;
    background: linear-gradient(135deg, #00aaff 0%, #0088cc 100%);
    color: white;
    margin: 0;
    text-shadow: 0 0 10px rgba(0, 150, 255, 0.8);
}

/* ===== Design 8: Neon Blue ===== */
.tab-container {
    overflow: hidden;
    border-radius: 12px;
}

.tab-container ul {
    margin: 0;
    padding: 0;
    list-style: none;
    display: flex;
    background: #0a0a0a;
    border-radius: 12px 12px 0 0;
    overflow: hidden;
    position: relative;
    box-shadow: 0 0 20px rgba(0, 150, 255, 0.3);
}

.tab-container ul::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(90deg, 
        transparent 0%, 
        rgba(0, 150, 255, 0.1) 50%, 
        transparent 100%);
    animation: neonPulse 3s ease-in-out infinite;
}

@keyframes neonPulse {
    0%, 100% { opacity: 0.3; }
    50% { opacity: 0.8; }
}

.tab-container ul li {
    flex: 1;
    padding: 16px 24px;
    text-align: center;
    cursor: pointer;
    transition: all 0.4s ease;
    position: relative;
    color: #00aaff;
    border-right: 1px solid rgba(0, 150, 255, 0.2);
    text-shadow: 0 0 5px rgba(0, 150, 255, 0.5);
    font-weight: 500;
}

.tab-container ul li:last-child {
    border-right: none;
}

.tab-container ul li.selected {
    color: #fff;
    background: linear-gradient(135deg, #00aaff 0%, #0088cc 100%);
    box-shadow: 
        0 0 20px rgba(0, 150, 255, 0.6),
        inset 0 2px 4px rgba(255, 255, 255, 0.2);
    text-shadow: 0 0 10px rgba(255, 255, 255, 0.8);
    animation: neonGlow 2s ease-in-out infinite alternate;
}

@keyframes neonGlow {
    from { 
        box-shadow: 
            0 0 20px rgba(0, 150, 255, 0.6),
            inset 0 2px 4px rgba(255, 255, 255, 0.2);
    }
    to { 
        box-shadow: 
            0 0 30px rgba(0, 150, 255, 0.8),
            inset 0 2px 4px rgba(255, 255, 255, 0.3);
    }
}

.tab-container ul li:not(.selected):hover {
    background: rgba(0, 150, 255, 0.1);
    color: #00ccff;
    text-shadow: 0 0 8px rgba(0, 150, 255, 0.7);
    transform: translateY(-1px);
}

.tab-container .tab-content {
    display: none;
    padding: 24px;
    min-height: 150px;
    background: linear-gradient(135deg, #0a0a0a 0%, #1a1a1a 100%);
    color: #00aaff;
    border-radius: 0 0 12px 12px;
    box-shadow: 
        0 4px 12px rgba(0, 0, 0, 0.5),
        0 0 20px rgba(0, 150, 255, 0.2);
    border: 1px solid rgba(0, 150, 255, 0.3);
    border-top: none;
    position: relative;
    overflow: hidden;
}

.tab-container .tab-content::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, 
        transparent 0%, 
        #00aaff 50%, 
        transparent 100%);
    animation: neonScan 2s linear infinite;
}

@keyframes neonScan {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}

.tab-container .tab-content.selected {
    display: block;
    animation: neonFadeIn 0.5s ease;
}

@keyframes neonFadeIn {
    from { 
        opacity: 0; 
        transform: translateY(-10px);
        box-shadow: 
            0 4px 12px rgba(0, 0, 0, 0.5),
            0 0 20px rgba(0, 150, 255, 0.1);
    }
    to { 
        opacity: 1; 
        transform: translateY(0);
        box-shadow: 
            0 4px 12px rgba(0, 0, 0, 0.5),
            0 0 20px rgba(0, 150, 255, 0.2);
    }
}

// Get tab container
const tabContainer = document.querySelector('.tab-container');
const tabMenuItems = tabContainer.querySelectorAll('ul li');
const tabContents = tabContainer.querySelectorAll('.tab-content');

// Set event listeners for each tab menu item
tabMenuItems.forEach(tabMenuItem => {
    tabMenuItem.addEventListener('click', () => {
        // Remove selected class from all tabs
        tabMenuItems.forEach(item => {
            item.classList.remove('selected');
        });
        
        // Add selected class only to clicked tab
        tabMenuItem.classList.add('selected');
        
        // Remove selected class from all tab contents
        tabContents.forEach(tabContent => {
            tabContent.classList.remove('selected');
        });

        // Add selected class to content with same ID as clicked tab's data attribute
        document.getElementById(tabMenuItem.dataset.id).classList.add('selected');
    });
});