:root {
    --bg-color: #0b0f19;
    --card-bg: rgba(255, 255, 255, 0.03);
    --card-border: rgba(255, 255, 255, 0.08);
    --text-primary: #f8f9fa;
    --text-secondary: #adb5bd;
    --accent: #ff4757;
    --accent-hover: #ff6b81;
    --btn-amazon: #f9a826;
    --btn-ebook: #4ca1af;
    --gradient-hero: linear-gradient(135deg, rgba(11,15,25,0.9) 0%, rgba(30,39,60,0.8) 100%);
    --font-heading: 'Oswald', 'Noto Sans JP', sans-serif;
    --font-body: 'Noto Sans JP', sans-serif;
}

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

body {
    font-family: var(--font-body);
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Header & Hero */
.header {
    position: relative;
    min-height: 70vh;
    display: flex;
    flex-direction: column;
    background: url('https://images.unsplash.com/photo-1614583225154-5fc2d1bf4eae?q=80&w=2000&auto=format&fit=crop') center/cover no-repeat;
    border-bottom: 2px solid var(--accent);
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--gradient-hero);
    z-index: 1;
}

.header-container {
    position: relative;
    z-index: 2;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 2rem;
    background: rgba(11, 15, 25, 0.5);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--card-border);
}

.logo {
    font-family: var(--font-heading);
    font-size: 2rem;
    font-weight: 700;
    letter-spacing: 1px;
}

.logo span {
    color: var(--accent);
}

.logo small {
    display: block;
    font-size: 0.8rem;
    font-family: var(--font-body);
    font-weight: 400;
    color: var(--text-secondary);
}

.nav-menu ul {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    font-size: 1rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 1px;
    transition: color 0.3s ease;
}

.nav-link:hover {
    color: var(--accent);
}

.hero-section {
    position: relative;
    z-index: 2;
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 2rem;
}

.hero-content {
    max-width: 800px;
    animation: fadeInDown 1s ease-out;
}

.hero-title {
    font-family: var(--font-heading);
    font-size: 4.5rem;
    font-weight: 900;
    margin-bottom: 1rem;
    line-height: 1.1;
    text-transform: uppercase;
    text-shadow: 0 4px 20px rgba(0,0,0,0.5);
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 2.5rem;
    font-weight: 400;
}

.btn-primary {
    display: inline-block;
    padding: 1rem 2.5rem;
    background-color: var(--accent);
    color: #fff;
    font-weight: 700;
    font-size: 1.1rem;
    border-radius: 50px;
    letter-spacing: 1px;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(255, 71, 87, 0.4);
}

.btn-primary:hover {
    background-color: var(--accent-hover);
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(255, 71, 87, 0.6);
}

/* Typography & Sections */
.section-title {
    font-family: var(--font-heading);
    font-size: 3rem;
    text-align: center;
    margin-bottom: 3rem;
    text-transform: uppercase;
    letter-spacing: 2px;
    position: relative;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background-color: var(--accent);
    border-radius: 2px;
}

.about-section {
    padding: 6rem 0;
    background-color: #0d1320;
}

.concept-text {
    text-align: center;
    font-size: 1.15rem;
    color: var(--text-secondary);
    max-width: 700px;
    margin: 0 auto 3rem;
    line-height: 2;
}

/* Ads */
.ad-slot {
    background: rgba(255,255,255,0.02);
    border: 1px dashed var(--card-border);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin: 2rem auto;
}

.ad-slot.horizontal {
    width: 100%;
    max-width: 728px;
    height: 90px;
}

.mt-xl {
    margin-top: 5rem;
}

/* Timeline & Filtering */
.timeline-section {
    padding: 6rem 0;
}

.filter-container {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 1rem;
    margin-bottom: 4rem;
}

.filter-btn {
    background: transparent;
    border: 1px solid var(--card-border);
    color: var(--text-primary);
    padding: 0.6rem 1.5rem;
    font-family: var(--font-heading);
    font-size: 1.1rem;
    border-radius: 30px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.filter-btn:hover, .filter-btn.active {
    background-color: var(--accent);
    border-color: var(--accent);
    box-shadow: 0 4px 10px rgba(255,71,87,0.3);
}

/* Manga Cards Grid */
.manga-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 2rem;
}

.manga-card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 16px;
    padding: 2rem;
    transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
    backdrop-filter: blur(10px);
    display: flex;
    flex-direction: column;
    position: relative;
    overflow: hidden;
    animation: fadeIn 0.6s ease-out forwards;
}

.manga-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: var(--accent);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.manga-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0,0,0,0.5);
    border-color: rgba(255,255,255,0.15);
}

.manga-card:hover::before {
    opacity: 1;
}

.card-header {
    margin-bottom: 1rem;
}

.card-era {
    font-family: var(--font-heading);
    font-size: 0.9rem;
    color: var(--accent);
    letter-spacing: 1px;
    margin-bottom: 0.5rem;
    font-weight: 700;
}

.card-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    line-height: 1.3;
}

.card-author {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.card-desc {
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 2rem;
    flex-grow: 1;
}

.card-actions {
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
    margin-top: auto;
}

.btn-affiliate {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    width: 100%;
    padding: 0.8rem;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 700;
    transition: all 0.3s ease;
}

.btn-affiliate.amazon {
    background-color: var(--btn-amazon);
    color: #111;
}

.btn-affiliate.amazon:hover {
    background-color: #f39c12;
}

.btn-affiliate.ebook {
    background-color: var(--btn-ebook);
    color: #fff;
}

.btn-affiliate.ebook:hover {
    background-color: #3b8b9a;
}

/* Footer */
.footer {
    background-color: #06090f;
    padding: 3rem 0;
    border-top: 1px solid var(--card-border);
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}

.footer-logo {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 700;
}

.footer-text {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Animations */
@keyframes fadeInDown {
    from { opacity: 0; transform: translateY(-30px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
    from { opacity: 0; transform: scale(0.95); }
    to { opacity: 1; transform: scale(1); }
}

/* Responsive */
@media (max-width: 768px) {
    .hero-title {
        font-size: 3rem;
    }
    
    .nav-menu {
        display: none; /* シンプル化のためスマホでは非表示かハンバーガー */
    }
    
    .section-title {
        font-size: 2.2rem;
    }
    
    .manga-grid {
        grid-template-columns: 1fr;
    }
}