@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+JP:wght@400;500;700;800&display=swap');

:root {
    --bg-color: #07070a;
    --bg-gradient: radial-gradient(circle at 50% -20%, #1a1a24 0%, #07070a 70%);
    /* Note: If we use background images in CSS, they should be ../images/filename.jpg */
    --text-color: #e9e9ee;
    --text-muted: #a0a0aa;
    --accent-color: #c7a24b;
    /* Luxury Gold */
    --accent-glow: rgba(199, 162, 75, 0.2);
    --nav-bg: rgba(7, 7, 10, 0.8);
    --card-bg: rgba(255, 255, 255, 0.03);
    --card-border: rgba(255, 255, 255, 0.06);
    --glass-blur: blur(16px);
    --container-width: 1100px;
    --section-spacing: 120px;
}

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

body {
    background-color: var(--bg-color);
    background-image: var(--bg-gradient);
    color: var(--text-color);
    font-family: 'Noto Sans JP', sans-serif;
    line-height: 1.8;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

/* Base Texture Overlay */
body::before {
    content: "";
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3BaseFilter id='noiseFilter'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.65' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noiseFilter)'/%3E%3C/svg%3E");
    opacity: 0.02;
    pointer-events: none;
    z-index: 9999;
}

/* ヘッダー・ナビゲーション */
header {
    position: fixed;
    top: 0;
    width: 100%;
    background: var(--nav-bg);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    z-index: 1000;
    border-bottom: 1px solid var(--card-border);
    transition: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

.nav-container {
    max-width: var(--container-width);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.25rem 2rem;
}

.logo {
    font-size: 1.25rem;
    font-weight: 800;
    color: var(--text-color);
    text-decoration: none;
    letter-spacing: 0.2em;
    transition: color 0.3s ease;
}

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

nav ul {
    display: flex;
    list-style: none;
    gap: 2.5rem;
}

nav a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.85rem;
    font-weight: 500;
    letter-spacing: 0.05em;
    transition: all 0.3s ease;
    position: relative;
}

nav a::after {
    content: "";
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 1px;
    background: var(--accent-color);
    transition: width 0.3s ease;
}

nav a:hover {
    color: var(--text-color);
}

nav a:hover::after {
    width: 100%;
}

nav a.active {
    color: var(--accent-color);
}

.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    background-size: cover;
    background-position: center;
    background-color: #000;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at center, rgba(7, 7, 10, 0.2) 0%, rgba(7, 7, 10, 0.8) 100%);
    z-index: 1;
}

.hero::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 30%;
    background: linear-gradient(to top, var(--bg-color), transparent);
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    max-width: 900px;
    padding: 0 2rem;
}

.hero h1 {
    font-size: clamp(2.5rem, 8vw, 4.5rem);
    font-weight: 800;
    margin-bottom: 1.5rem;
    color: #fff;
    letter-spacing: 0.1em;
    text-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

.hero p {
    font-size: clamp(1rem, 2vw, 1.25rem);
    color: var(--text-muted);
    font-weight: 400;
    max-width: 600px;
    margin: 0 auto 2.5rem;
    letter-spacing: 0.05em;
}

/* Scroll Down Indicator */
.scroll-indicator {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 2;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
    color: var(--text-muted);
    font-size: 0.75rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    opacity: 0.6;
}

.scroll-indicator::after {
    content: "";
    width: 1px;
    height: 60px;
    background: linear-gradient(to bottom, var(--accent-color), transparent);
}

main {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 2rem;
}

section {
    margin-bottom: var(--section-spacing);
    padding: 4rem;
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 24px;
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    transition: transform 0.4s ease, border-color 0.4s ease;
}

section:hover {
    border-color: rgba(199, 162, 75, 0.2);
}

h2 {
    font-size: 1.75rem;
    font-weight: 800;
    color: var(--accent-color);
    margin-bottom: 2.5rem;
    display: flex;
    align-items: center;
    gap: 1.5rem;
    letter-spacing: 0.1em;
}

h2::after {
    content: '';
    flex: 1;
    height: 1px;
    background: linear-gradient(to right, rgba(199, 162, 75, 0.5), transparent);
}

p {
    margin-bottom: 1.5rem;
}

/* YouTube レスポンシブ容器 */
.video-container {
    position: relative;
    padding-bottom: 56.25%;
    /* 16:9 */
    height: 0;
    overflow: hidden;
    margin: 3rem 0;
    border-radius: 16px;
    border: 1px solid var(--card-border);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

/* Image Presentation */
img {
    max-width: 100%;
    height: auto;
    border-radius: 16px;
    transition: transform 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.img-container {
    overflow: hidden;
    border-radius: 16px;
    border: 1px solid var(--card-border);
}

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

/* Scroll Reveal */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

.reveal.active {
    opacity: 1;
    transform: translateY(0);
}

/* Radial Glow Effects */
section {
    position: relative;
    overflow: hidden;
}

section::before {
    content: "";
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at center, var(--accent-glow) 0%, transparent 70%);
    opacity: 0;
    transition: opacity 1s ease;
    pointer-events: none;
    z-index: -1;
}

section:hover::before {
    opacity: 1;
}

/* フッター */
footer {
    background: #050507;
    padding: 6rem 2rem;
    text-align: center;
    border-top: 1px solid var(--card-border);
    position: relative;
}

.footer-nav {
    margin-bottom: 3rem;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 2rem;
}

.footer-nav a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.8rem;
    font-weight: 500;
    transition: color 0.3s ease;
}

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

.social-links {
    margin-bottom: 3rem;
}

.social-links a {
    color: var(--text-color) !important;
    text-decoration: none;
    margin: 0 1.5rem;
    font-size: 0.9rem;
    opacity: 0.6;
    transition: opacity 0.3s ease;
}

.social-links a:hover {
    opacity: 1;
}

.copyright {
    color: #444;
    font-size: 0.75rem;
    letter-spacing: 0.1em;
}

/* CTA ボタン */
.cta-button {
    display: inline-block;
    padding: 1.25rem 3rem;
    background: var(--accent-color);
    border: none;
    border-radius: 50px;
    color: #000;
    text-decoration: none;
    font-weight: 800;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    transition: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    box-shadow: 0 10px 20px rgba(199, 162, 75, 0.2);
}

.cta-button:hover {
    transform: translateY(-4px);
    box-shadow: 0 15px 30px rgba(199, 162, 75, 0.4);
    filter: brightness(1.1);
}

/* System Lists */
#system ul {
    list-style: none;
    margin: 2.5rem 0;
}

#system li {
    padding: 1.25rem 0;
    border-bottom: 1px solid var(--card-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 500;
}

#system li:last-child {
    border-bottom: none;
}

#system li::before {
    content: "•";
    color: var(--accent-color);
    margin-right: 1rem;
    font-weight: 800;
}

/* モバイル対応 */
@media (max-width: 768px) {
    .nav-container {
        flex-direction: column;
        gap: 1rem;
    }

    .hero h1 {
        font-size: 2.2rem;
    }

    main {
        margin: 2rem auto;
    }
}