/* stylelint-disable */

:root {
    /* Color Palette - Premium SF Theme */
    --color-bg-deep: #050A1F;
    --color-bg-card: rgb(15 25 50 / 70%);
    --color-text-main: #E2E8F0;
    --color-text-muted: #94A3B8;
    --color-accent-blue: #00F0FF;
    --color-accent-blue-glow: rgb(0 240 255 / 40%);
    --color-border: rgb(255 255 255 / 10%);

    /* Typography */
    --font-family-body: 'Inter', 'Noto Sans JP', sans-serif;
    --font-family-display: 'Inter', 'Noto Sans JP', sans-serif;

    /* Dimensions & Spacing */
    --container-max-width: 1200px;
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 5rem;

    /* Reduced from 6rem */

    /* Effects */
    --shadow-glow: 0 0 20px var(--color-accent-blue-glow);
    --transition-base: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
}

/* Reset & Base */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

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

/* -----------------------------
   グローバルリンク（左上親サイト動線）
------------------------------ */
.global-tech-sphere-link {
    position: fixed;
    top: 25px;
    left: 25px;
    z-index: 1000;
    text-decoration: none;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 80px;
    height: 80px;
}

.global-tech-sphere-link:hover {
    transform: translateY(-2px);
}

.global-tech-sphere-link:hover .logo-layer-text {
    filter: drop-shadow(0 0 15px rgb(0 240 255 / 80%));
}

.logo-layer-globe {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 100%;
    height: 100%;
    object-fit: contain;
    opacity: 0.3; /* 背景レイヤーとして少し透過 */
    animation: rotateGlobe 60s linear infinite; /* ゆっくり回転させる演出 */
    pointer-events: none;
}

.logo-layer-text {
    position: relative;
    z-index: 2;
    width: 85%; /* 地球儀に対してテキストの占める割合 */
    height: auto;
    object-fit: contain;
    transition: all 0.3s ease;
}

@keyframes rotateGlobe {
    from { transform: translate(-50%, -50%) rotate(0deg); }
    to { transform: translate(-50%, -50%) rotate(360deg); }
}

#bg-canvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: -1;
    opacity: 0.6;
}

.container {
    width: 100%;
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
}

/* Typography Utilities */
.text-center {
    text-align: center;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 16px 28px;
    min-width: 260px;
    width: auto;
    white-space: nowrap;
    word-break: keep-all;
    font-weight: 600;
    text-decoration: none;
    border-radius: 4px;
    transition: var(--transition-base);
    cursor: pointer;
    border: none;
    font-family: inherit;
    font-size: 1rem;
}

.btn--primary {
    background: linear-gradient(135deg, var(--color-accent-blue), #00A3FF);
    color: var(--color-bg-deep);
    box-shadow: 0 4px 15px rgb(0 240 255 / 30%);
}

.btn--primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-glow);
}

.btn--secondary {
    background: transparent;
    color: var(--color-text-main);
    border: 1px solid var(--color-accent-blue);
}

.btn--secondary:hover {
    background: rgb(0 240 255 / 10%);
    box-shadow: inset 0 0 10px rgb(0 240 255 / 20%);
}

.btn--text {
    background: transparent;
    color: var(--color-accent-blue);
    padding: 0.5rem 0;
    font-size: 0.9rem;
    position: relative;
}

.btn--text::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 1px;
    background-color: var(--color-accent-blue);
    transform: scaleX(0);
    transform-origin: right;
    transition: transform 0.3s ease;
}

.btn--text:hover::after {
    transform: scaleX(1);
    transform-origin: left;
}

.btn--full {
    width: 100%;
}

/* Layout Components */
.card-style {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: 8px;
    padding: var(--spacing-md);
    backdrop-filter: blur(10px);
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: var(--spacing-xl) var(--spacing-sm);
    position: relative;
}

.hero__content {
    max-width: 800px;
    z-index: 1;
    animation: fadeIn 1s ease-out forwards;
    padding-bottom: 80px;

    /* 余白を確保してScroll要素との重なりを防止 */
}

/* -----------------------------
   技術圏レイヤー追加スタイル
------------------------------ */
.hero__tech-sphere {
    margin-bottom: 3rem; /* 既存コンテンツとの距離 */
    display: flex;
    flex-direction: column;
    align-items: center;
    position: relative;
    z-index: 10;
}

.tech-sphere-main {
    font-family: "Hiragino Mincho ProN", "Yu Mincho", serif;
    font-size: clamp(3.5rem, 10vw, 8rem);
    font-weight: 900;
    line-height: 1;
    letter-spacing: 0.1em;
    color: rgb(255 255 255 / 95%);
    text-shadow: 0 0 20px rgb(0 240 255 / 40%), 0 0 40px rgb(0 240 255 / 20%);
    margin-bottom: 1rem;
    position: relative;
}

.tech-sphere-main .small-dot {
    font-size: 0.5em;
    color: var(--color-accent-blue);
    text-shadow: 0 0 10px var(--color-accent-blue);
    vertical-align: bottom;
}

.tech-sphere-sub {
    font-family: "Hiragino Mincho ProN", "Yu Mincho", serif;
    font-size: clamp(1rem, 2.5vw, 1.5rem);
    font-weight: 300;
    letter-spacing: 0.2em;
    color: rgb(255 255 255 / 70%);
}

.tech-sphere-label {
    position: absolute;
    top: 5px;
    left: 5px;
    background: rgb(0 240 255 / 10%);
    color: var(--color-accent-blue);
    border: 1px solid rgb(0 240 255 / 30%);
    font-size: 0.65rem;
    font-weight: bold;
    padding: 0.2rem 0.5rem;
    border-radius: 2px;
    letter-spacing: 0.05em;
    z-index: 2;
}

.hero__logos {
    margin-bottom: var(--spacing-md);
    font-size: 1.2rem;
    font-weight: 600;
    letter-spacing: 0.1em;
}

.hero__logos .cross {
    color: var(--color-accent-blue);
    margin: 0 0.5rem;
}

.hero__title {
    font-size: clamp(2rem, 5vw, 4rem);
    font-weight: 900;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
    letter-spacing: 0.05em;
}

.hero__title-line {
    display: block;
}

.hero__title-subline {
    display: block;
    margin-top: 0.5rem;
    font-size: clamp(1rem, 3.5vw, 1.8rem);

    /* 1行に収めるためのフォントサイズ調整 */
    font-weight: 500;

    /* メインタイトルよりウェイトを下げてサブタイトル感強調 */
    letter-spacing: 0.1em;
}

.hero__title .highlight {
    background: linear-gradient(to right, #E2E8F0, var(--color-accent-blue));
    background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero__subtitle {
    font-size: 1.1rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-lg);
}

.hero__info {
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-sm);
    border-top: 1px solid rgb(255 255 255 / 10%);
    border-bottom: 1px solid rgb(255 255 255 / 10%);
    display: inline-block;
}

.hero__cta-group {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

.scroll-indicator {
    position: absolute;
    bottom: var(--spacing-md);
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    font-size: 0.8rem;
    color: var(--color-text-muted);
    letter-spacing: 0.1em;
    animation: pulse 2s infinite;
    pointer-events: none;
}

.scroll-indicator .arrow {
    width: 1px;
    height: 40px;
    background: linear-gradient(to bottom, transparent, var(--color-accent-blue));
    margin-top: 0.5rem;
}


/* Section Titles */
.section-title {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: var(--spacing-xl);
    text-align: center;
    letter-spacing: 0.1em;
    color: var(--color-accent-blue);
}

.section-subtitle {
    display: block;
    font-size: 1rem;
    color: var(--color-text-main);
    font-weight: 400;
    margin-top: 0.5rem;
}

/* Themes Section */
.themes-section {
    padding: var(--spacing-xl) 0;
}

.themes-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xl);
}

.theme-card {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    padding: var(--spacing-md) var(--spacing-sm);
    border-radius: 8px;
    text-align: center;
    transition: var(--transition-base);
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.theme-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--color-accent-blue);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.3s ease;
}

.theme-card:hover {
    transform: translateY(-5px);
    border-color: rgb(0 240 255 / 30%);
    box-shadow: 0 10px 30px rgb(0 0 0 / 50%);
}

.theme-card:hover::before {
    transform: scaleX(1);
}

.theme-card__number {
    font-size: 2rem;
    font-weight: 900;
    color: rgb(255 255 255 / 5%);
    position: absolute;
    top: -5px;
    right: 5px;
}

.theme-card__title {
    font-size: 1.2rem;
    margin-bottom: var(--spacing-xs);
    position: relative;
    z-index: 1;
}

.theme-card__copy {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-sm);
    position: relative;
    z-index: 1;
}

/* Theme Details (Accordion Content) */
.theme-detail {
    display: none;

    /* Initially hidden, managed by JS */
    animation: slideDown 0.4s ease-out;
}

.theme-detail.active {
    display: block;
}

.theme-detail__header {
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.theme-detail__title {
    font-size: 2rem;
    margin-bottom: var(--spacing-sm);
}

.theme-category {
    margin-bottom: var(--spacing-xl);
}

.theme-category__title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    text-align: center;
    border-bottom: 1px solid rgb(255 255 255 / 10%);
    padding-bottom: 0.5rem;
    letter-spacing: 0.05em;
}

.theme-category__title .highlight-text {
    color: var(--color-accent-blue);
}

.books-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-md);
}

.book-block {
    flex: 1;
    display: flex;
    gap: var(--spacing-md);
    background: rgb(255 255 255 / 2%);
    padding: var(--spacing-md);
    border-radius: 8px;
    border: 1px solid rgb(255 255 255 / 5%);
}

.book-cover {
    width: 140px;
    height: 200px;
    min-width: 140px;
    max-width: 140px;
    min-height: 200px;
    max-height: 200px;
    background-color: #2a2a2a;
    border-radius: 4px;
    flex-shrink: 0;
    box-shadow: 5px 5px 15px rgb(0 0 0 / 50%);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    position: relative;
}

.book-block.placeholder {
    opacity: 0.5;
    border: 1px dashed rgb(255 255 255 / 20%);
    background: transparent;
}

.book-cover.placeholder-cover {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.9rem;
    color: var(--color-text-muted);
    background-color: rgb(255 255 255 / 2%);
    box-shadow: inset 0 0 10px rgb(0 0 0 / 50%);
}

.book-info {
    flex: 1;
    display: flex;
    flex-direction: column;
}

.book-type {
    font-size: 0.8rem;
    color: var(--color-accent-blue);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: 0.2rem;
}

.book-title {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
}

.book-desc {
    font-size: 0.9rem;
    color: var(--color-text-muted);
    margin-bottom: 1rem;
    flex-grow: 1;
}

.author-comment {
    display: none;

    /* 一時的に非表示（正式決定後に解除） */
    margin-top: var(--spacing-md);
    padding-top: var(--spacing-md);
    border-top: 1px dashed rgb(255 255 255 / 10%);
}

.author-comment__inner {
    display: flex;
    gap: var(--spacing-md);
    align-items: flex-start;
    background: rgb(0 240 255 / 2%);
    padding: var(--spacing-md);
    border-radius: 8px;
}

.author-comment__img {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    object-fit: cover;
    flex-shrink: 0;
    border: 2px solid var(--color-accent-blue);
}

.author-comment__text-block {
    flex: 1;
}

.author-comment__text {
    font-size: 0.95rem;
    font-style: italic;
    margin-bottom: 0.5rem;
    color: var(--color-text-main);
}

.author-comment__name {
    font-size: 0.9rem;
    font-weight: bold;
    color: var(--color-accent-blue);
}

.author-comment__role {
    font-size: 0.8rem;
    color: var(--color-text-muted);
    font-weight: normal;
    margin-left: 0.5rem;
}

.theme-cta {
    text-align: center;
    margin-top: var(--spacing-md);
    padding: var(--spacing-sm);
    background: rgb(0 0 0 / 20%);
    border-radius: 4px;
}

/* Benefits Section */
.benefits-section {
    padding: var(--spacing-xl) 0;
    background: linear-gradient(to bottom, transparent, rgb(0 240 255 / 3%));
}

.benefits-title {
    font-family: var(--font-family-display);
    font-size: 2.5rem;
    font-weight: 900;
    letter-spacing: 0.15em;
    color: var(--color-text-main);
    margin-bottom: var(--spacing-xl);
    position: relative;
    display: block;
    text-align: center;
    padding-bottom: 0.5rem;
}

.benefits-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 1px;
    background-color: var(--color-accent-blue);
}

.benefits-subtitle {
    display: block;
    font-size: 1rem;
    font-weight: 500;
    letter-spacing: 0.1em;
    color: var(--color-text-muted);
    margin-top: 0.5rem;
}

.benefits-content {
    display: flex;
    gap: var(--spacing-lg);
    align-items: center;
}

.benefits-visual {
    flex: 1;
}

.image-placeholder {
    width: 100%;
    aspect-ratio: 16/9;
    background: rgb(255 255 255 / 5%);
    border: 1px dashed rgb(255 255 255 / 20%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text-muted);
    border-radius: 8px;
}

.benefits-info {
    flex: 1;
}

.benefits-desc {
    font-size: 1.5rem;
    font-weight: bold;
    margin-bottom: var(--spacing-xl);
    line-height: 1.4;
    text-align: center;
}

.purchase-methods {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.method.highlight {
    border-color: var(--color-accent-blue);
    background: rgb(0 240 255 / 5%);
}

.method h4 {
    margin-bottom: 0.5rem;
    color: var(--color-text-main);
}

.method p {
    color: var(--color-text-muted);
    margin-bottom: 1rem;
}

/* Closing Section */
.closing-section {
    padding: var(--spacing-xl) 0;
}

.closing-text {
    font-size: 1.5rem;
    line-height: 2;
    margin-bottom: var(--spacing-md);
}

.highlight-text {
    color: var(--color-accent-blue);
    font-weight: bold;
}

/* Footer */
.footer {
    padding: var(--spacing-md) 0;
    border-top: 1px solid var(--color-border);
    text-align: center;
}

.footer-logos {
    margin-bottom: 1rem;
    font-weight: bold;
}

.footer-links {
    margin-bottom: 1rem;
}

.footer-links a {
    color: var(--color-text-muted);
    text-decoration: none;
    margin: 0 0.5rem;
    font-size: 0.9rem;
}

.footer-links a:hover {
    color: var(--color-text-main);
}

.copyright {
    color: var(--color-text-muted);
    font-size: 0.8rem;
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes pulse {
    0% {
        opacity: 0.5;
    }

    50% {
        opacity: 1;
    }

    100% {
        opacity: 0.5;
    }
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Responsive */
@media (width <= 992px) {
    .themes-grid {
        grid-template-columns: repeat(3, 1fr);
    }

    .books-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .benefits-content {
        flex-direction: column;
    }
}

@media (width <= 768px) {
    :root {
        --spacing-xl: 4rem;
    }

    .hero__cta-group {
        flex-direction: column;
    }

    .themes-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .books-grid {
        grid-template-columns: 1fr;
    }

    .book-block {
        flex-direction: column;
        align-items: center;
        text-align: center;
    }
}

@media (width <= 576px) {
    .themes-grid {
        grid-template-columns: 1fr;
    }

}

/* Archive Section */
.archive-section {
    padding: var(--spacing-xl) 0;
    position: relative;
    border-top: 1px solid rgb(255 255 255 / 5%);
}

.archive-list {
    max-width: 800px;
    margin: 0 auto;
}

.archive-item {
    border-bottom: 1px solid rgb(255 255 255 / 10%);
}

.archive-item__header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md) 0;
    cursor: pointer;
    transition: var(--transition-base);
}

.archive-item__header:hover {
    color: var(--color-accent-blue);
}

.archive-item__info {
    flex: 1;
}

.archive-item__title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 0.25rem;
}

.archive-item__meta {
    font-size: 0.85rem;
    color: var(--color-text-muted);
}

.archive-item__icon {
    font-size: 1.5rem;
    font-weight: 300;
    color: var(--color-accent-blue);
    margin-left: var(--spacing-sm);
    transition: transform 0.3s ease;
}

.archive-item.active .archive-item__icon {
    transform: rotate(45deg);
}

.archive-item__content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease-out, padding 0.4s ease-out;
}

.archive-item.active .archive-item__content {
    max-height: 2000px;
    padding-bottom: var(--spacing-md);
}

.archive-item__empty-msg {
    text-align: center;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-sm);
    font-style: italic;
}

.archive-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
}

.archive-photo-placeholder {
    aspect-ratio: 4/3;
    background: rgb(255 255 255 / 2%);
    border: 1px dashed rgb(255 255 255 / 15%);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.9rem;
    color: var(--color-text-muted);
    border-radius: 4px;
    cursor: pointer;
    transition: var(--transition-base);
}

.archive-photo-placeholder:hover {
    background: rgb(255 255 255 / 5%);
    border-color: rgb(255 255 255 / 30%);
}

@media (width <= 768px) {
    .archive-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (width <= 480px) {}

/* Subtle Concept Tag for Footer */
.concept-tag {
    font-family: var(--font-family-display);
    font-size: 0.75rem;
    font-weight: 400;
    letter-spacing: 0.1em;
    display: inline-block;
    text-decoration: none;
    color: var(--color-text-muted);
    opacity: 0.3;
    margin: var(--spacing-sm) 0;
    text-align: center;
    user-select: none;
    transition: opacity 0.3s ease;
    cursor: pointer;
}

.concept-tag:hover {
    opacity: 0.6;
}

.series-section {
    background-color: var(--color-bg-primary);
    border-bottom: 1px solid var(--color-bg-tertiary);
}

.series-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 6rem;
    align-items: center;
}

@media (width <= 900px) {
    .series-layout {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .progress-labels {
        justify-content: space-between;
    }
}

.section-label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--color-accent);
}

.series-desc {
    margin-bottom: 3rem;
}

.progress-indicator {
    margin-bottom: 3rem;
    max-width: 400px;
}

.progress-labels {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.5rem;
    font-size: 0.875rem;
    color: var(--color-text-secondary);
}

.progress-bar {
    height: 4px;
    background-color: var(--color-bg-tertiary);
    border-radius: 2px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background-color: var(--color-accent);
}

.btn-notify {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 2rem;
    background-color: var(--color-bg-primary);
    color: var(--color-text-primary);
    border: 1px solid var(--color-text-primary);
    border-radius: 4px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-notify:hover {
    background-color: var(--color-text-primary);
    color: var(--color-bg-primary);
}

/* 3D Book Mockup CSS */
.book-mockup {
    perspective: 1000px;
    display: flex;
    justify-content: center;
}

.book {
    position: relative;
    width: 320px;
    height: 460px;
    transform-style: preserve-3d;
    transform: rotateY(-15deg) rotateX(5deg);
    box-shadow: 20px 20px 30px rgb(0 0 0 / 10%),
        inset 4px 0 10px rgb(255 255 255 / 50%);
    transition: transform 0.3s;
}

.book:hover {
    transform: rotateY(-5deg) rotateX(2deg);
}

.mockup-book-cover {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: #0f172a;
    color: white;
    padding: 3rem 2rem;
    display: flex;
    flex-direction: column;
    border-radius: 2px 6px 6px 2px;
    z-index: 2;
    overflow: hidden;
}

.book-spine {
    position: absolute;
    top: 0;
    left: -30px;
    width: 30px;
    height: 100%;
    background-color: #020617;
    transform-origin: right;
    transform: rotateY(-90deg);
}

.book-spine::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to right,
            rgb(255 255 255 / 10%) 0%,
            rgb(0 0 0 / 30%) 100%);
}

.book-title-area {
    z-index: 10;
}

.book-tag {
    color: var(--color-accent);
    font-size: 1rem;
    margin-bottom: 1rem;
}

.book-title {
    font-size: 2.25rem;
    font-weight: 800;
    line-height: 1.1;
    letter-spacing: 0.05em;
}

.book-author {
    margin-top: auto;
    font-size: 0.875rem;
    color: #94a3b8;
    z-index: 10;
}

.book-tech-bg {
    position: absolute;
    bottom: -50px;
    right: -50px;
    width: 200px;
    height: 200px;
    border-radius: 50%;
    background: radial-gradient(circle, var(--color-accent) 0%, transparent 70%);
    opacity: 0.2;
    z-index: 1;
}

.book-tech-bg::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: linear-gradient(rgb(255 255 255 / 10%) 1px, transparent 1px);
    background-size: 10px 10px;
}

.footer-cta.footer-section {
    background-color: var(--color-text-primary);
    color: var(--color-bg-primary);
    padding: 8rem 0 4rem;
}

.cta-container {
    background-color: var(--color-bg-primary);
    color: var(--color-text-primary);
    padding: 4rem;
    border-radius: 8px;
    margin-bottom: 6rem;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.cta-container::after {
    content: "";
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at top right, rgb(2 132 199 / 5%), transparent 50%);
    pointer-events: none;
}

.cta-content {
    position: relative;
    z-index: 10;
    max-width: 600px;
    margin: 0 auto;
}

.cta-title {
    margin-bottom: 1.5rem;
}

.cta-desc {
    margin-bottom: 3rem;
}

.subscribe-form {
    display: flex;
    gap: 1rem;
}

@media (width <= 600px) {
    .subscribe-form {
        flex-direction: column;
    }
}

.input-group {
    position: relative;
    flex-grow: 1;
}

.mail-icon {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--color-text-muted);
}

.email-input {
    width: 100%;
    padding: 1rem 1rem 1rem 3rem;
    border: 1px solid var(--color-bg-tertiary);
    border-radius: 4px;
    background-color: var(--color-bg-secondary);
    font-family: inherit;
    font-size: 1rem;
}

.email-input:focus {
    outline: none;
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px var(--color-accent-light);
}

.btn-subscribe {
    white-space: nowrap;
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: flex-end;
    gap: 4rem;
    border-top: 1px solid rgb(255 255 255 / 10%);
    padding-top: 4rem;
}

@media (width <= 900px) {
    .footer-bottom {
        flex-direction: column;
        align-items: flex-start;
    }
}

.brand-logo {
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 1.5rem;
}

.text-muted {
    color: #64748b;
    font-size: 0.875rem;
}

.footer-links {
    display: flex;
    gap: 4rem;
}

.link-column h4 {
    color: #64748b;
    font-size: 0.75rem;
    margin-bottom: 1.5rem;
    letter-spacing: 0.1em;
}

.link-column ul {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.link-column a {
    color: var(--color-bg-primary);
    font-size: 0.875rem;
}

.link-column a:hover {
    color: var(--color-accent-light);
}

/* === SF footer alignment fix (override) === */
.footer-bottom {
    display: flex;
    justify-content: center;
    align-items: center;
    text-align: center;
    width: 100%;
}

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

.link-column ul {
    align-items: center;
}

/* モバイルでも中央寄せを維持 */
@media (width <= 900px) {
    .footer-bottom,
    .footer-links {
        justify-content: center;
        align-items: center;
    }
}

/* =========================================
   Timeline Section
   ========================================= */

.timeline-tabs {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-bottom: 4rem;
}

.timeline-tab-btn {
    background: transparent;
    border: none;
    color: rgb(255 255 255 / 60%);
    font-size: 1.2rem;
    font-weight: 700;
    padding: 0.5rem 1.5rem;
    cursor: pointer;
    border-bottom: 2px solid transparent;
    transition: all 0.3s ease;
    letter-spacing: 0.05em;
}

.timeline-tab-btn:hover {
    color: rgb(255 255 255 / 90%);
}

.timeline-tab-btn.active {
    color: var(--color-accent-blue);
    border-bottom: 2px solid var(--color-accent-blue);
    text-shadow: 0 0 10px rgb(0 240 255 / 50%);
}

.timeline-item--publisher .timeline-content {
    border: 1px solid rgb(255 215 0 / 50%);
    box-shadow: 0 0 15px rgb(255 215 0 / 10%);
}

.timeline-item--publisher .timeline-marker {
    border-color: rgb(255 215 0 / 80%);
    box-shadow: 0 0 10px rgb(255 215 0 / 30%);
}

.timeline-container {
    position: relative;
    max-width: 900px;
    margin: 4rem auto 0;
    padding: 2rem 0;
}

.timeline-container::before {
    content: '';
    position: absolute;
    top: 0;
    bottom: 0;
    left: 50%;
    width: 2px;
    background: rgb(0 240 255 / 20%);
    transform: translateX(-50%);
}

.timeline-item {
    position: relative;
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 4rem;
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.timeline-item.active {
    opacity: 1;
    transform: translateY(0);
}

.timeline-item:nth-child(odd) {
    flex-direction: row-reverse;
}

.timeline-marker {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--color-bg);
    border: 3px solid rgb(0 240 255 / 50%);
    z-index: 2;
    transition: all 0.3s ease;
}

.timeline-item.active .timeline-marker {
    border-color: var(--color-accent);
    box-shadow: 0 0 15px rgb(0 240 255 / 80%);
    background: var(--color-accent);
}

.timeline-year {
    width: 45%;
    text-align: right;
    font-family: var(--font-english);
    font-size: 2.5rem;
    font-weight: 700;
    color: rgb(255 255 255 / 10%);
    letter-spacing: 0.1em;
    padding: 0 2rem;
    transition: color 0.3s ease;
}

.timeline-item:nth-child(odd) .timeline-year {
    text-align: left;
}

.timeline-item.active .timeline-year {
    color: rgb(0 240 255 / 80%);
}

.timeline-content {
    width: 45%;
    background: rgb(10 20 45 / 60%);
    backdrop-filter: blur(10px);
    border: 1px solid rgb(0 240 255 / 10%);
    border-radius: 12px;
    padding: 2rem;
    position: relative;
    box-shadow: 0 10px 30px rgb(0 0 0 / 30%);
    transition: border-color 0.3s ease, transform 0.3s ease;
}

.timeline-item.active .timeline-content {
    border-color: rgb(0 240 255 / 40%);
}

.timeline-content:hover {
    transform: translateY(-5px);
    border-color: rgb(0 240 255 / 60%);
}

/* Timeline detail rows */
.timeline-detail-row {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 0.8rem;
    font-size: 0.9rem;
}

.timeline-detail-label {
    flex: 0 0 100px;
    color: var(--color-primary);
    font-weight: bold;
    font-size: 0.8rem;
    padding-top: 0.2rem;
}

.timeline-detail-value {
    flex: 1;
    color: #e0e0e0;
}

.timeline-stars {
    color: var(--color-accent);
    letter-spacing: 2px;
}

/* =========================================
   Book Sets Section
   ========================================= */
.book-sets-section {
    position: relative;
    z-index: 2;
}

.book-set-pair {
    display: flex;
    justify-content: space-between;
    align-items: stretch;
    background: rgb(10 20 45 / 40%);
    border: 1px solid rgb(255 255 255 / 5%);
    border-radius: 16px;
    padding: 3rem;
    margin-bottom: 4rem;
    gap: 3rem;
}

.book-set-divider {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    color: rgb(0 240 255 / 30%);
    font-weight: 300;
}

/* Re-use exiting book-block styles but ensure horizontal layout */

.book-set-pair .book-block {
    display: flex;
    flex-direction: column;
}

.book-set-pair .book-block-inner {
    display: flex;
    flex-direction: row;
    gap: 1.5rem;
    align-items: flex-start;
}

.book-set-pair .book-cover {
    flex: 0 0 150px;
    height: 220px;
    margin-bottom: 0;
}

.book-set-pair .book-info {
    text-align: left;
}


.book-set-pair .book-cover {
    height: 250px;
    margin-bottom: 2rem;
    position: relative;
    transform-style: preserve-3d;
    perspective: 1000px;
}

.book-set-pair .book-info {
    text-align: center;
    display: flex;
    flex-direction: column;
    flex: 1;
}

.book-set-pair .book-title {
    font-size: 1.2rem;
    margin-bottom: 1rem;
    color: var(--color-text);
}

.book-set-pair .book-desc {
    font-size: 0.9rem;
    line-height: 1.6;
    color: #b0b0b0;
    margin-bottom: 1.5rem;
    text-align: left;
    flex: 1;
}

/* =========================================
   Responsive Adjustments
   ========================================= */
@media (width <= 768px) {
    .timeline-container::before {
        left: 30px;
    }

    .timeline-item {
        flex-direction: column !important;
        align-items: flex-start;
        padding-left: 70px;
        margin-bottom: 3rem;
    }

    .timeline-marker {
        left: 30px;
        top: 0;
        transform: translate(-50%, 0);
    }

    .timeline-year {
        width: 100%;
        text-align: left !important;
        padding: 0;
        margin-bottom: 1rem;
        font-size: 2rem;
    }

    .timeline-content {
        width: 100%;
    }

    .book-set-pair {
        flex-direction: column;
        padding: 2rem;
        gap: 2rem;
    }

    .book-set-divider {
        transform: rotate(90deg);
        margin: -1rem 0;
    }
}

/* Reset grid for book sets container if needed */
#book-sets-container {
    display: flex;
    flex-direction: column;

    /* Stack the PAIRS vertically */
    gap: 3rem;
}

/* Clickable Timeline Items */
a.timeline-content--clickable {
    display: block;
    text-decoration: none;
    cursor: pointer;
    transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
}

a.timeline-content--clickable:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgb(0 240 255 / 15%);
    border-color: rgb(0 240 255 / 50%);
}

/* 内部のテキスト色が変わらないように指定 */
a.timeline-content--clickable h4 {
    transition: color 0.3s ease;
}

a.timeline-content--clickable:hover h4 {
    color: #fff !important;

    /* ホバー時に少し明るく */
    text-shadow: 0 0 10px rgb(0 240 255 / 50%);
}

/* Fix default link color for clickable timeline cards */
a.timeline-content--clickable {
    color: var(--color-text, #e0e0e0);
}

a.timeline-content--clickable p,
a.timeline-content--clickable div {
    color: inherit;
}

/* =========================================
   Interview Note Sections
   ========================================= */

.interview-note {
    background: linear-gradient(135deg, rgb(10 20 45 / 80%) 0%, rgb(5 10 31 / 90%) 100%);
    backdrop-filter: blur(10px);
    border: 1px solid rgb(0 240 255 / 15%);
    border-left: 4px solid var(--color-accent-blue);
    border-radius: 8px;
    padding: 2.5rem 3rem 2.5rem 2.5rem;
    position: relative;
    box-shadow: 0 10px 30px rgb(0 0 0 / 50%), inset 0 0 20px rgb(0 240 255 / 5%);
    margin-top: 2rem;
    margin-bottom: 2rem;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.interview-note:hover {
    transform: translateY(-2px);
    box-shadow: 0 15px 40px rgb(0 0 0 / 60%), inset 0 0 30px rgb(0 240 255 / 10%);
}

.interview-note--connected {
    margin-top: 0;
}

.interview-note--connected::before {
    content: '';
    position: absolute;
    top: -4rem;
    left: 2rem;
    width: 2px;
    height: 4rem;
    background: linear-gradient(to bottom, transparent, var(--color-accent-blue));
    opacity: 0.6;
}

.interview-note__label {
    position: absolute;
    top: -12px;
    left: 1rem;
    background: var(--color-bg);
    color: var(--color-accent-blue);
    font-size: 0.75rem;
    font-weight: 700;
    padding: 0.2rem 0.8rem;
    border: 1px solid var(--color-accent-blue);
    border-radius: 4px;
    letter-spacing: 0.05em;
    box-shadow: 0 0 10px rgb(0 240 255 / 20%);
}

.interview-note__text {
    font-size: 1.05rem;
    line-height: 1.8;
    color: #e0e0e0;
    margin-bottom: 1.5rem;
    font-style: normal;
}

.interview-note__author {
    display: block;
    text-align: right;
    font-size: 0.85rem;
    color: var(--color-accent-blue);
    font-weight: bold;
    opacity: 0.8;
}

.interview-note--large {
    background: linear-gradient(135deg, rgb(10 20 45 / 90%) 0%, rgb(5 10 31 / 95%) 100%);
    backdrop-filter: blur(10px);
    border: 1px solid rgb(0 240 255 / 15%);
    border-left: 4px solid var(--color-accent-blue);
    border-radius: 12px;
    padding: 6rem 3rem;
    text-align: center;
    margin: 6rem auto;
    max-width: 900px;
    position: relative;
    overflow: hidden;
    box-shadow: 0 10px 40px rgb(0 0 0 / 60%), inset 0 0 30px rgb(0 240 255 / 5%);
}

.interview-note--large::before {
    content: "“";
    position: absolute;
    top: -2rem;
    left: 50%;
    transform: translateX(-50%);
    font-size: 20rem;
    color: rgb(0 240 255 / 3%);
    font-family: serif;
    line-height: 1;
    z-index: 0;
    pointer-events: none;
}

.interview-note--large .interview-note__text {
    font-size: 1.6rem;
    line-height: 2.2;
    max-width: 800px;
    margin: 0 auto 3rem;
    font-weight: 600;
    position: relative;
    z-index: 1;
    color: #fff;
    text-shadow: 0 2px 10px rgb(0 0 0 / 80%);
}

.interview-note--large .interview-note__label {
    position: relative;
    top: 0;
    left: 0;
    display: inline-block;
    margin-bottom: 3rem;
    background: transparent;
    border: none;
    font-size: 0.9rem;
    letter-spacing: 0.15em;
    opacity: 0.8;
    box-shadow: none;
    z-index: 1;
}

.interview-note--large .interview-note__author {
    text-align: center;
    font-size: 1rem;
    position: relative;
    z-index: 1;
}

.interview-archive {
    background: linear-gradient(180deg, rgb(10 20 45 / 40%) 0%, rgb(5 10 31 / 80%) 100%);
    border: 1px solid rgb(0 240 255 / 20%);
    border-radius: 12px;
    padding: 4rem 3rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    margin: 6rem auto;
    max-width: 800px;
    box-shadow: 0 10px 40px rgb(0 0 0 / 50%);
}

.interview-archive__title {
    color: var(--color-accent-blue);
    font-size: 1.1rem;
    letter-spacing: 0.15em;
    margin-bottom: 1.5rem;
    font-weight: 700;
}

.interview-archive__subtitle {
    font-size: 1.6rem;
    font-weight: 800;
    margin-bottom: 2rem;
    line-height: 1.5;
    color: #fff;
}

.interview-archive__desc {
    color: #b0b0b0;
    line-height: 1.8;
    margin-bottom: 1.5rem;
    max-width: 600px;
}

.interview-archive .btn {
    margin: 2.5rem 0;
}

.interview-archive__meta {
    font-size: 0.85rem;
    color: var(--color-text-muted);
}