/* ==========================================================================
   CSS Variables & Settings
   ========================================================================== */
:root {
    /* Colors */
    --color-bg-start: #ffffff;
    --color-bg-end: #f0f2f5;
    --color-text-main: #1a1b1e;
    --color-text-sub: #54565a;
    --color-white: #ffffff;
    --color-border: rgba(26, 27, 30, 0.1);
    
    /* Glassmorphism */
    --glass-bg: rgba(255, 255, 255, 0.4);
    --glass-bg-hover: rgba(255, 255, 255, 0.6);
    --glass-border: rgba(255, 255, 255, 0.5);
    --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.04);
    
    /* Dark Glass (for overlays) */
    --dark-glass-bg: rgba(0, 0, 0, 0.2);
    
    /* Typography */
    --font-serif: 'Shippori Mincho', 'Cinzel', serif;
    --font-sans: 'Inter', 'Noto Sans JP', 'Helvetica Neue', sans-serif;
    
    /* Transitions */
    --transition-slow: 0.8s cubic-bezier(0.25, 1, 0.5, 1);
    --transition-normal: 0.4s cubic-bezier(0.25, 1, 0.5, 1);
    --transition-fast: 0.2s ease-out;
    
    /* Spacing */
    --space-sm: 1rem;
    --space-md: 3.75rem;
    --space-lg: 7.5rem;
    --space-xl: 12rem;
    --space-xxl: 18rem;
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-sans);
    color: var(--color-text-main);
    background-color: var(--color-bg-start);
    line-height: 1.8;
    overflow-x: hidden;
    font-weight: 300;
    letter-spacing: 0.05em;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-serif);
    font-weight: 400;
    line-height: 1.4;
    letter-spacing: 0.08em;
}

a {
    color: inherit;
    text-decoration: none;
    transition: var(--transition-normal);
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

/* ==========================================================================
   Utility Classes
   ========================================================================== */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 5%;
}

.section-padding {
    padding: var(--space-xxl) 0;
}

@media (max-width: 768px) {
    .section-padding {
        padding: var(--space-xl) 0;
    }
}

.relative {
    position: relative;
}

.mt-4 { margin-top: 1rem; }
.mt-6 { margin-top: 2rem; }
.mt-8 { margin-top: 3rem; }
.block { display: block; }

.bg-light-glass {
    position: relative;
}
.bg-light-glass::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to bottom, transparent, rgba(255, 255, 255, 0.8), transparent);
    z-index: -1;
    pointer-events: none;
}

/* ==========================================================================
   Background Effects (Ambient Glow)
   ========================================================================== */
.ambient-background {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: -2;
    background: linear-gradient(135deg, var(--color-bg-start), var(--color-bg-end));
    overflow: hidden;
}

.ambient-glow {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.5;
    animation: float 20s infinite alternate ease-in-out;
}

.glow-1 {
    width: 60vw;
    height: 60vw;
    background: radial-gradient(circle, rgba(255,255,255,0.8) 0%, transparent 70%);
    top: -10%;
    left: -10%;
    animation-delay: 0s;
}

.glow-2 {
    width: 50vw;
    height: 50vw;
    background: radial-gradient(circle, rgba(240,244,248,0.8) 0%, transparent 70%);
    bottom: -10%;
    right: -10%;
    animation-delay: -5s;
}

.glow-3 {
    width: 40vw;
    height: 40vw;
    background: radial-gradient(circle, rgba(255,255,255,0.6) 0%, transparent 70%);
    top: 40%;
    left: 40%;
    animation-delay: -10s;
}

@keyframes float {
    0% { transform: translate(0, 0) scale(1); }
    100% { transform: translate(5%, 10%) scale(1.1); }
}

/* ==========================================================================
   Glassmorphism UI Components
   ========================================================================== */
.glass-frame {
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    box-shadow: var(--glass-shadow);
    border-radius: 2px;
    overflow: hidden;
}

.glass-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 1rem 2.5rem;
    background: rgba(255, 255, 255, 0.7);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border: 1px solid rgba(255, 255, 255, 0.8);
    color: var(--color-text-main);
    font-family: var(--font-serif);
    font-size: 0.9rem;
    letter-spacing: 0.1em;
    position: relative;
    overflow: hidden;
    transition: var(--transition-normal);
    cursor: pointer;
}

.glass-btn:hover {
    background: rgba(255, 255, 255, 0.95);
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
}

.glass-btn .btn-text {
    position: relative;
    z-index: 2;
}

.glass-btn .btn-ripple {
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: radial-gradient(circle, rgba(255,255,255,1) 0%, transparent 70%);
    transform: translate(-50%, -50%);
    border-radius: 50%;
    opacity: 0;
    z-index: 1;
    transition: width 0.6s ease-out, height 0.6s ease-out, opacity 0.6s ease-out;
}

.glass-btn:hover .btn-ripple {
    width: 300px;
    height: 300px;
    opacity: 0.5;
}

.glass-btn.large {
    padding: 1.25rem 3rem;
    font-size: 1rem;
}

/* ==========================================================================
   Header
   ========================================================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 100;
    padding: 1.5rem 5%;
    transition: var(--transition-normal);
    background: rgba(255, 255, 255, 0.6);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.2);
}

.header.scrolled {
    padding: 1rem 5%;
    background: rgba(255, 255, 255, 0.6);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.3);
}

.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1400px;
    margin: 0 auto;
}

.logo {
    font-family: 'Cinzel', serif;
    font-size: 1.5rem;
    font-weight: 400;
    letter-spacing: 0.15em;
    color: var(--color-text-main);
}

.header-nav {
    display: flex;
    gap: 2.5rem;
}

.header-nav a {
    font-size: 0.8rem;
    letter-spacing: 0.15em;
    font-weight: 500;
    transition: opacity 0.3s;
}

.header-nav a:hover {
    opacity: 0.6;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.lang-switch {
    font-size: 0.8rem;
    letter-spacing: 0.1em;
    color: var(--color-text-sub);
}

.lang-switch .active {
    color: var(--color-text-main);
}

.lang-switch .sep {
    margin: 0 0.5rem;
    color: rgba(26, 27, 30, 0.3);
}

.btn-ticket {
    font-size: 0.85rem;
    letter-spacing: 0.1em;
    padding: 0.6rem 1.5rem;
    border: 1px solid var(--color-border);
    border-radius: 20px;
    transition: var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.btn-ticket::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.8), transparent);
    transition: var(--transition-fast);
}

.btn-ticket:hover {
    background: var(--color-text-main);
    color: var(--color-white);
    border-color: var(--color-text-main);
}

.btn-ticket:hover::before {
    left: 100%;
    transition: 0.6s ease-in-out;
}

@media (max-width: 768px) {
    .header-right .lang-switch {
        display: none;
    }
}

/* ==========================================================================
   Hero Section
   ========================================================================== */
.hero {
    height: 100vh;
    min-height: 700px;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    isolation: isolate;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5); /* ダークオーバーレイで視認性を劇的に向上 */
    z-index: 0;
    pointer-events: none;
}

.hero-bg {
    position: absolute;
    top: -5%;
    left: -5%;
    width: 110%;
    height: 110%;
    background-size: cover;
    background-position: center;
    z-index: -1;
    opacity: 0.6;
    filter: blur(2px) contrast(1.1);
    /* mask-image to create ethereal fade at bottom */
    -webkit-mask-image: linear-gradient(to bottom, black 50%, transparent 100%);
    mask-image: linear-gradient(to bottom, black 50%, transparent 100%);
}

.hero-content {
    text-align: center;
    max-width: 800px;
    padding: 0 5%;
    z-index: 1;
}

.hero-title {
    font-size: clamp(2rem, 4vw, 3.5rem);
    line-height: 1.5;
    margin-bottom: 2rem;
    color: #ffffff; /* 白文字に変更 */
    text-shadow: 0 4px 15px rgba(0, 0, 0, 0.6); /* 暗い背景に合うシャドウ */
    position: relative;
    z-index: 2;
}

.hero-sub {
    font-size: clamp(0.9rem, 1.5vw, 1.1rem);
    color: rgba(255, 255, 255, 0.9); /* 白に近い色 */
    margin-bottom: 3.5rem;
    position: relative;
    z-index: 2;
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.6);
    font-weight: 400;
}

.scroll-indicator {
    position: absolute;
    bottom: 3rem;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}

.scroll-text {
    font-size: 0.7rem;
    letter-spacing: 0.2em;
    font-family: var(--font-serif);
}

.scroll-line {
    width: 1px;
    height: 60px;
    background: rgba(26, 27, 30, 0.2);
    position: relative;
    overflow: hidden;
}

.scroll-line::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 30%;
    background: var(--color-text-main);
    animation: scroll-down 2s infinite ease-in-out;
}

@keyframes scroll-down {
    0% { top: -30%; opacity: 0; }
    50% { opacity: 1; }
    100% { top: 100%; opacity: 0; }
}

/* ==========================================================================
   Typography & Shared Layouts
   ========================================================================== */
.subtitle {
    display: block;
    font-size: 0.75rem;
    letter-spacing: 0.2em;
    color: var(--color-text-sub);
    margin-bottom: 1.5rem;
    font-family: var(--font-sans);
}

.section-title {
    font-size: clamp(1.8rem, 3vw, 2.5rem);
    line-height: 1.5;
    margin-bottom: 2.5rem;
}

.section-body p {
    margin-bottom: 1.5rem;
    color: var(--color-text-sub);
}

.concept-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 9rem;
    align-items: center;
}

.concept-grid.reverse {
    direction: rtl;
}

.concept-grid.reverse > * {
    direction: ltr;
}

@media (max-width: 992px) {
    .concept-grid {
        grid-template-columns: 1fr;
        gap: 3rem;
    }
    .concept-grid.reverse {
        direction: ltr;
    }
}

.image-wrapper {
    position: relative;
    overflow: hidden;
    aspect-ratio: 4/5;
}

.image-wrapper img {
    width: 100%;
    height: 120%; /* For parallax */
    object-fit: cover;
    display: block;
    filter: grayscale(80%) contrast(1.1) brightness(1.1);
}

.image-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(255,255,255,0.2) 0%, rgba(255,255,255,0) 100%);
    pointer-events: none;
}

/* ==========================================================================
   Exhibit 01 (Carousel)
   ========================================================================== */
.section-header {
    text-align: center;
    max-width: 600px;
    margin: 0 auto 5rem;
}

.exhibit-layout {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 6rem;
    align-items: center;
}

@media (max-width: 992px) {
    .exhibit-layout {
        grid-template-columns: 1fr;
    }
}

.exhibit-info {
    color: var(--color-text-sub);
}

.carousel-container {
    position: relative;
}

.carousel {
    position: relative;
    padding: 1rem;
}

.carousel-track {
    display: flex;
    gap: 2rem;
    overflow-x: auto;
    scroll-snap-type: x mandatory;
    scrollbar-width: none; /* Firefox */
    -ms-overflow-style: none;  /* IE and Edge */
    cursor: grab;
}

.carousel-track::-webkit-scrollbar {
    display: none;
}

.carousel-track:active {
    cursor: grabbing;
}

.carousel-slide {
    flex: 0 0 80%;
    scroll-snap-align: center;
    aspect-ratio: 16/10;
    border-radius: 2px;
    overflow: hidden;
    position: relative;
}

.carousel-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s ease;
    filter: grayscale(80%) contrast(1.1) brightness(1.1);
}

.carousel-slide:hover .carousel-img {
    transform: scale(1.05);
}

.carousel-placeholder {
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.3);
    backdrop-filter: blur(10px);
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px dashed rgba(26, 27, 30, 0.2);
}

.placeholder-content {
    text-align: center;
}

.placeholder-title {
    display: block;
    font-family: var(--font-serif);
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.placeholder-desc {
    font-size: 0.8rem;
    color: var(--color-text-sub);
    letter-spacing: 0.1em;
}

.carousel-nav {
    display: flex;
    justify-content: space-between;
    position: absolute;
    top: 50%;
    left: -1.5rem;
    right: -1.5rem;
    transform: translateY(-50%);
    pointer-events: none;
}

.carousel-btn {
    width: 3rem;
    height: 3rem;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.9);
    border: 1px solid var(--color-border);
    color: var(--color-text-main);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    pointer-events: auto;
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
    transition: var(--transition-fast);
}

.carousel-btn:hover {
    background: var(--color-text-main);
    color: var(--color-white);
}

.drag-hint {
    text-align: center;
    font-size: 0.75rem;
    letter-spacing: 0.1em;
    color: var(--color-text-sub);
    margin-top: 1.5rem;
    font-style: italic;
}

@media (max-width: 768px) {
    .carousel-slide {
        flex: 0 0 90%;
    }
    .carousel-nav {
        display: none;
    }
}

/* ==========================================================================
   Exhibit 02 (Accordion)
   ========================================================================== */
.accordion-item {
    border-bottom: 1px solid var(--color-border);
}

.accordion-header {
    width: 100%;
    background: none;
    border: none;
    padding: 1.5rem 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    font-family: var(--font-serif);
    font-size: 1rem;
    color: var(--color-text-main);
    text-align: left;
}

.accordion-icon {
    font-size: 1.5rem;
    font-weight: 300;
    transition: transform var(--transition-normal);
}

.accordion-item.is-active .accordion-icon {
    transform: rotate(45deg);
}

.accordion-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-normal) ease;
}

.accordion-inner {
    padding-bottom: 1.5rem;
    font-size: 0.9rem;
    color: var(--color-text-sub);
    line-height: 1.8;
}

/* ==========================================================================
   Access Section
   ========================================================================== */
.access-layout {
    display: grid;
    grid-template-columns: 5fr 7fr;
    gap: 7.5rem;
    align-items: center;
}

@media (max-width: 992px) {
    .access-layout {
        grid-template-columns: 1fr;
    }
}

.access-list {
    margin-top: 3rem;
    border-top: 1px solid var(--color-border);
}

.access-list li {
    display: flex;
    padding: 1.5rem 0;
    border-bottom: 1px solid var(--color-border);
}

@media (max-width: 576px) {
    .access-list li {
        flex-direction: column;
        gap: 0.5rem;
    }
}

.access-label {
    flex: 0 0 120px;
    font-size: 0.8rem;
    letter-spacing: 0.1em;
    color: var(--color-text-sub);
}

.access-value {
    flex: 1;
    font-family: var(--font-serif);
    font-size: 1rem;
}

/* ==========================================================================
   Bottom CTA
   ========================================================================== */
.bottom-cta {
    position: relative;
    padding: var(--space-xxl) 0;
    text-align: center;
    overflow: hidden;
    min-height: 80vh;
    display: flex;
    align-items: center;
    justify-content: center;
    isolation: isolate; /* z-index contextを生成し、背景画像の消失を防ぐ */
}

.cta-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    z-index: -2;
}

.cta-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    background: rgba(255, 255, 255, 0.4);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
}

.cta-title {
    font-size: clamp(2rem, 4vw, 3rem);
    margin-bottom: 1.5rem;
}

.cta-sub {
    font-size: 1rem;
    color: var(--color-text-main);
}

.micro-copy {
    font-size: 0.75rem;
    color: var(--color-text-sub);
    letter-spacing: 0.05em;
}

/* ==========================================================================
   Footer
   ========================================================================== */
.footer {
    padding: 4rem 0 2rem;
    background: var(--color-white);
    text-align: center;
}

.footer-logo {
    font-family: 'Cinzel', serif;
    font-size: 1.2rem;
    letter-spacing: 0.2em;
    margin-bottom: 2rem;
    color: rgba(26, 27, 30, 0.5);
}

.footer-copyright {
    font-size: 0.75rem;
    color: rgba(26, 27, 30, 0.4);
    line-height: 2;
}

.footer-link {
    display: inline-block;
    transition: var(--transition-fast);
}

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

/* ==========================================================================
   Animations (Triggered by JS)
   ========================================================================== */
.js-fade-up {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 1s cubic-bezier(0.25, 1, 0.5, 1), transform 1s cubic-bezier(0.25, 1, 0.5, 1);
}

.js-fade-up.is-inview {
    opacity: 1;
    transform: translateY(0);
}

.delay-1 { transition-delay: 0.1s; }
.delay-2 { transition-delay: 0.2s; }
.delay-3 { transition-delay: 0.3s; }