:root {
    /* Base Colors - Corporate & Trustworthy */
    --bg-body: #f8fafc;
    /* Crisp white-gray */
    --bg-surface: #ffffff;
    --bg-surface-alt: #f1f5f9;

    /* Text Colors - High Contrast & Sharp */
    --text-primary: #0f172a;
    /* Slate 900 */
    --text-secondary: #334155;
    /* Slate 700 - Slightly darker for readability */
    --text-tertiary: #64748b;
    /* Slate 500 */

    /* Brand Colors - Deep & Refined (Trustworthy) */
    --brand-primary: #020617;
    /* Very Dark Navy */
    --brand-accent: #0f52ba;
    /* Sapphire Blue - Professional & Calm */
    --brand-accent-light: #3b82f6;
    /* Blue 500 - Clear & Modern */

    /* Functional Colors */
    --border-color: #e2e8f0;
    --border-hover: #94a3b8;

    /* Dark Theme */
    --bg-dark: #0b1120;
    /* Deepest Navy */
    --text-on-dark: #f8fafc;
    --text-on-dark-secondary: #cbd5e1;
    --border-on-dark: #1e293b;

    /* Shadows - Sophisticated & Sharp */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -1px rgba(0, 0, 0, 0.04);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -2px rgba(0, 0, 0, 0.04);
    --shadow-card: 0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);

    /* Layout & Shape */
    --radius-sm: 2px;
    --radius-md: 4px;
    --radius-lg: 8px;

    /* Typography */
    --font-heading: 'Cormorant Garamond', serif;
    --font-body: 'Noto Sans JP', sans-serif;
}

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

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

body {
    font-family: var(--font-body);
    background-color: var(--bg-body);
    color: var(--text-primary);
    line-height: 1.75;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Typography Utilities */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-family: var(--font-heading);
    color: var(--text-primary);
    line-height: 1.2;
    font-weight: 600;
}

p {
    margin-bottom: 1.5rem;
}

a {
    text-decoration: none;
    color: inherit;
    transition: all 0.2s ease;
}

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

/* Background Layers - removed twinkle, kept subtle gradient */
.night-bg {
    display: none;
    /* Removed for cleaner look */
}

/* Header */
header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    width: 30px;
    height: 24px;
    position: relative;
    z-index: 1001;
    padding: 0;
}

.mobile-menu-btn span {
    display: block;
    width: 100%;
    height: 2px;
    background-color: var(--text-primary);
    position: absolute;
    left: 0;
    transition: all 0.3s ease;
}

.mobile-menu-btn span:nth-child(1) {
    top: 0;
}

.mobile-menu-btn span:nth-child(2) {
    top: 11px;
}

.mobile-menu-btn span:nth-child(3) {
    bottom: 0;
}

.mobile-menu-btn.active span:nth-child(1) {
    transform: rotate(45deg);
    top: 11px;
}

.mobile-menu-btn.active span:nth-child(2) {
    opacity: 0;
}

.mobile-menu-btn.active span:nth-child(3) {
    transform: rotate(-45deg);
    bottom: 11px;
}

body.no-scroll {
    overflow: hidden;
}

.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.logo img {
    height: 40px;
    width: auto;
    mix-blend-mode: multiply;
    transition: opacity 0.2s ease;
}

.logo:hover img {
    opacity: 0.7;
}

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

nav a {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
    position: relative;
    padding-bottom: 0.25rem;
    letter-spacing: 0.02em;
}

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

nav a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 1px;
    /* Thinner line */
    background-color: var(--brand-accent);
    transition: width 0.3s ease;
}

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

/* Hero Section */
.hero {
    background-color: var(--bg-dark);
    color: var(--text-on-dark);
    padding: 180px 0 140px;
    position: relative;
    overflow: hidden;
}

/* Subtle graphic element for hero */
/* Subtle graphic element for hero */
.hero::after {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 80%;
    height: 200%;
    /* More sophisticated, deeper gradient */
    background: radial-gradient(circle, rgba(15, 82, 186, 0.12) 0%, rgba(11, 17, 32, 0) 65%);
    z-index: 1;
    pointer-events: none;
}

.hero-content {
    max-width: 720px;
    position: relative;
    z-index: 2;
}

.hero-tagline {
    font-family: var(--font-heading);
    font-size: 1.25rem;
    color: var(--brand-accent-light);
    letter-spacing: 0.05em;
    margin-bottom: 1.5rem;
    font-weight: 500;
}

.hero h1 {
    font-size: 4rem;
    color: var(--text-on-dark);
    margin-bottom: 2rem;
    letter-spacing: -0.02em;
    line-height: 1.1;
}

.hero-lead {
    font-size: 1.125rem;
    color: var(--text-on-dark-secondary);
    margin-bottom: 3rem;
    max-width: 600px;
    line-height: 1.8;
}

/* Sections Global */
section {
    padding: 120px 0;
}

.section-header {
    margin-bottom: 4rem;
    text-align: center;
}

.section-label {
    display: inline-block;
    padding: 0.4rem 1.2rem;
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-size: 0.7rem;
    font-weight: 600;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--brand-accent);
    margin-bottom: 1.5rem;
}

.section-title {
    font-size: 2.5rem;
    color: var(--text-primary);
    position: relative;
}

/* About Section */
.about {
    background-color: var(--bg-surface);
}

.about-vision {
    font-family: var(--font-heading);
    font-size: 2rem;
    color: var(--brand-accent);
    text-align: center;
    max-width: 800px;
    margin: 0 auto 4rem;
    line-height: 1.4;
}

.about-content {
    max-width: 800px;
    margin: 0 auto;
    font-size: 1.1rem;
    color: var(--text-secondary);
}

.about-content a {
    color: var(--brand-accent);
    border-bottom: 1px solid var(--border-color);
}

.about-content a:hover {
    border-bottom-color: var(--brand-accent);
}

.about-mission {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
    max-width: 700px;
    margin: 3rem auto;
}

.mission-item {
    background: var(--bg-surface);
    padding: 2.5rem 2rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    text-align: center;
    box-shadow: var(--shadow-sm);
}

.mission-item h3 {
    font-size: 1.25rem;
    color: var(--brand-accent);
    margin-bottom: 1rem;
}

.mission-item p {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin: 0;
    line-height: 1.7;
}

/* Products Section */
.products {
    background-color: var(--bg-body);
}

.products-intro {
    text-align: center;
    max-width: 700px;
    margin: -2rem auto 4rem;
    font-size: 1.1rem;
    color: var(--text-secondary);
}

.product-block {
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 3.5rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow-card);
    transition: box-shadow 0.3s ease, transform 0.3s ease;
    display: grid;
    grid-template-columns: 1.5fr 1fr;
    gap: 4rem;
    align-items: start;
}




.product-header {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    margin-bottom: 1rem;
}

.product-name {
    font-size: 2rem;
    color: var(--brand-primary);
}

.product-status {
    font-size: 0.7rem;
    padding: 0.2rem 0.6rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 600;
    color: var(--text-tertiary);
}

.product-status.active {
    background: #ecfdf5;
    color: #059669;
    border-color: #a7f3d0;
}

.product-tagline {
    display: block;
    font-size: 1.1rem;
    color: var(--brand-accent);
    margin-bottom: 2rem;
    font-weight: 500;
}

.product-desc {
    color: var(--text-secondary);
    font-size: 1rem;
    margin-bottom: 1.5rem;
}

.product-link {
    display: inline-block;
    margin-top: 1rem;
    padding: 0.9rem 2rem;
    background-color: var(--brand-primary);
    color: #fff;
    border-radius: var(--radius-md);
    font-weight: 500;
    font-size: 0.9rem;
    transition: all 0.2s ease;
    letter-spacing: 0.02em;
}

.product-link:hover {
    background-color: var(--text-primary);
    transform: translateY(-1px);
}

.product-features {
    background: var(--bg-surface-alt);
    padding: 2.5rem;
    border-radius: var(--radius-md);
    border: 1px solid transparent;
    /* Prepare for hover borders if needed */
    display: grid;
    gap: 2rem;
}

.feature-item h4 {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
    border-left: 2px solid var(--brand-accent);
    padding-left: 1rem;
}

.feature-item p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin: 0;
    padding-left: 1rem + 2px;
    /* indent flush with text */
}

/* Community & Activity */
.community {
    background-color: var(--bg-surface);
    text-align: center;
}

.community-content {
    max-width: 800px;
    margin: 0 auto;
}

.community-note {
    display: inline-block;
    margin-top: 2rem;
    padding: 1rem 2rem;
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    background: var(--bg-surface);
    border-radius: var(--radius-md);
    font-weight: 500;
    font-size: 0.9rem;
}

.activity {
    background-color: var(--bg-body);
}

.activity-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.activity-item {
    background: var(--bg-surface);
    padding: 3rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
}

.activity-item h3 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.zenn-cards {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.zenn-card {
    background: var(--bg-surface);
    padding: 1.5rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.zenn-card h4 {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.zenn-card p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.zenn-card-links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.zenn-link {
    display: inline-block;
    color: var(--brand-accent);
    font-weight: 600;
    font-size: 0.85rem;
    padding: 0.4rem 0.8rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    transition: all 0.2s ease;
}

.zenn-link:hover {
    background-color: var(--brand-accent);
    color: #fff;
}

/* FAQ & Contact */
.faq {
    background-color: var(--bg-surface);
}

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

details {
    padding: 1.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

summary {
    font-weight: 600;
    cursor: pointer;
    list-style: none;
    position: relative;
    padding-right: 2rem;
    color: var(--brand-primary);
    transition: color 0.2s ease;
}

summary:hover {
    color: var(--brand-accent);
}

summary::-webkit-details-marker {
    display: none;
}

summary::after {
    content: '+';
    position: absolute;
    right: 0;
    top: 0;
    font-size: 1.5rem;
    font-weight: 300;
    line-height: 1;
}

details[open] summary::after {
    content: '−';
}

details p {
    margin-top: 1rem;
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.contact {
    background-color: var(--bg-dark);
    color: var(--text-on-dark);
    text-align: center;
}

.contact .section-title {
    color: var(--text-on-dark);
}

.contact-email {
    display: inline-block;
    font-size: 2rem;
    font-family: var(--font-heading);
    color: var(--text-on-dark);
    border-bottom: 1px solid var(--border-on-dark);
    padding-bottom: 0.5rem;
    transition: all 0.2s ease;
}

.contact-email:hover {
    color: var(--brand-accent-light);
    border-bottom-color: var(--brand-accent-light);
}

/* Footer */
footer {
    background-color: #020617;
    /* Even darker than dark bg */
    color: #94a3b8;
    padding: 4rem 0;
    border-top: 1px solid #1e293b;
    font-size: 0.9rem;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-links {
    display: flex;
    gap: 2rem;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .mobile-menu-btn {
        display: block;
    }

    nav {
        position: fixed;
        top: 0;
        right: -100%;
        width: 100%;
        height: 100vh;
        background: rgba(255, 255, 255, 0.98);
        padding: 100px 2rem 2rem;
        transition: right 0.3s ease;
        display: block;
        /* Override display: none from previous media query if any */
    }

    nav.active {
        right: 0;
        box-shadow: -5px 0 15px rgba(0, 0, 0, 0.1);
    }

    nav ul {
        flex-direction: column;
        align-items: center;
        gap: 2rem;
    }

    nav a {
        font-size: 1.25rem;
    }

    section {
        padding: 80px 0;
    }

    .hero {
        padding: 140px 0 100px;
    }

    .hero h1 {
        font-size: 2.5rem;
    }

    .product-block {
        grid-template-columns: 1fr;
        padding: 2rem;
        gap: 2rem;
    }

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

    .about-vision {
        font-size: 1.5rem;
    }

    .about-mission {
        grid-template-columns: 1fr;
    }

    .footer-content {
        flex-direction: column;
        gap: 1.5rem;
        text-align: center;
    }
}

/* Animations - Sophisticated & Subtle */
.fade-in-section {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.8s ease-out, transform 0.8s cubic-bezier(0.25, 1, 0.5, 1);
    will-change: opacity, transform;
}

.fade-in-section.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Reduced motion preference */
@media (prefers-reduced-motion: reduce) {
    .fade-in-section {
        opacity: 1;
        transform: none;
        transition: none;
    }
}