:root {
    --color-bg: #0a0a0f;
    --color-bg-secondary: #12121a;
    --color-bg-tertiary: #1a1a25;
    --color-text: #e8e8f0;
    --color-text-muted: #9a9ab0;
    --color-accent: #6c8cff;
    --color-accent-hover: #5a75e8;
    --color-success: #4ade80;
    --color-warning: #fbbf24;
    --color-danger: #f87171;
    --color-border: #2a2a3a;
    --font-main: 'Helvetica Neue', Arial, sans-serif;
    --font-serif: 'Georgia', serif;
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 3rem;
    --spacing-xl: 4rem;
    --border-radius: 8px;
    --shadow-card: 0 4px 6px rgba(0, 0, 0, 0.3);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-main);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.7;
    font-size: 16px;
}

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: color 0.2s ease;
}

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

/* Header & Navigation */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(10, 10, 15, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    z-index: 1000;
    padding: var(--spacing-sm) 0;
}

.main-nav {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-brand a {
    display: flex;
    flex-direction: column;
    color: var(--color-text);
}

.brand-kanji {
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: 0.1em;
}

.brand-subtitle {
    font-size: 0.75rem;
    color: var(--color-text-muted);
    letter-spacing: 0.05em;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: var(--spacing-md);
}

.nav-links a {
    color: var(--color-text-muted);
    font-size: 0.9rem;
    padding: var(--spacing-xs) 0;
    border-bottom: 2px solid transparent;
    transition: all 0.2s ease;
}

.nav-links a:hover {
    color: var(--color-text);
    border-bottom-color: var(--color-accent);
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-xs);
}

.mobile-menu-toggle span {
    width: 24px;
    height: 2px;
    background: var(--color-text);
    transition: all 0.3s ease;
}

/* Hero Section */
.hero {
    padding: calc(80px + var(--spacing-xl)) var(--spacing-md) var(--spacing-xl);
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    align-items: center;
}

.hero-content {
    padding-right: var(--spacing-lg);
}

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.1rem;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-lg);
    line-height: 1.8;
}

.hero-cta {
    display: flex;
    gap: var(--spacing-sm);
}

.btn {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius);
    font-weight: 600;
    text-align: center;
    transition: all 0.2s ease;
    cursor: pointer;
    border: none;
    font-size: 0.95rem;
}

.btn-primary {
    background: var(--color-accent);
    color: white;
}

.btn-primary:hover {
    background: var(--color-accent-hover);
    color: white;
}

.btn-secondary {
    background: transparent;
    color: var(--color-text);
    border: 2px solid var(--color-border);
}

.btn-secondary:hover {
    border-color: var(--color-accent);
}

.btn-outline {
    background: transparent;
    color: var(--color-accent);
    border: 2px solid var(--color-accent);
}

.btn-outline:hover {
    background: var(--color-accent);
    color: white;
}

.btn-disabled {
    background: var(--color-bg-tertiary);
    color: var(--color-text-muted);
    cursor: not-allowed;
    border: 2px solid var(--color-border);
}

.hero-quote blockquote {
    font-family: var(--font-serif);
    font-size: 1.1rem;
    padding: var(--spacing-md);
    border-left: 4px solid var(--color-accent);
    background: var(--color-bg-secondary);
    border-radius: var(--border-radius);
}

.hero-quote p {
    margin-bottom: var(--spacing-sm);
}

.hero-quote p:last-child {
    margin-bottom: 0;
}

/* Sections */
.section {
    padding: var(--spacing-xl) var(--spacing-md);
}

.section-container {
    max-width: 1200px;
    margin: 0 auto;
}

.section-title {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    text-align: center;
}

.section-intro {
    text-align: center;
    color: var(--color-text-muted);
    max-width: 700px;
    margin: 0 auto var(--spacing-lg);
    font-size: 1.05rem;
}

/* Philosophy Section */
.philosophy-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
}

.philosophy-card {
    background: var(--color-bg-secondary);
    padding: var(--spacing-md);
    border-radius: var(--border-radius);
    border: 1px solid var(--color-border);
}

.philosophy-card h3 {
    font-size: 1.1rem;
    margin-bottom: var(--spacing-sm);
    color: var(--color-accent);
}

.philosophy-card p {
    font-size: 0.95rem;
    color: var(--color-text-muted);
}

/* Case Studies */
.case-timeline {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.case-card {
    background: var(--color-bg-secondary);
    padding: var(--spacing-md);
    border-radius: var(--border-radius);
    border: 1px solid var(--color-border);
    transition: all 0.3s ease;
}

.case-card:hover {
    border-color: var(--color-accent);
    transform: translateY(-2px);
    box-shadow: var(--shadow-card);
}

.case-card.featured {
    border-color: var(--color-accent);
    background: linear-gradient(135deg, var(--color-bg-secondary), var(--color-bg-tertiary));
}

.case-meta {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
}

.case-number {
    font-size: 0.8rem;
    color: var(--color-accent);
    font-weight: 600;
}

.case-tag {
    font-size: 0.8rem;
    color: var(--color-text-muted);
    background: var(--color-bg-tertiary);
    padding: 2px 8px;
    border-radius: 4px;
}

.case-title {
    font-size: 1.3rem;
    margin-bottom: var(--spacing-sm);
}

.case-excerpt {
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-md);
    font-size: 0.95rem;
}

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

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

/* Analysis Section */
.analysis-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
}

.analysis-card {
    background: var(--color-bg-secondary);
    padding: var(--spacing-md);
    border-radius: var(--border-radius);
    border: 1px solid var(--color-border);
    transition: all 0.3s ease;
    display: block;
}

.analysis-card:hover {
    border-color: var(--color-accent);
    transform: translateY(-2px);
    box-shadow: var(--shadow-card);
}

.analysis-card h3 {
    font-size: 1.2rem;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.analysis-card p {
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-sm);
    font-size: 0.95rem;
}

.analysis-list {
    list-style: none;
    margin-top: var(--spacing-sm);
}

.analysis-list li {
    font-size: 0.85rem;
    color: var(--color-text-muted);
    padding: 4px 0;
    padding-left: 16px;
    position: relative;
}

.analysis-list li::before {
    content: '•';
    color: var(--color-accent);
    position: absolute;
    left: 0;
}

.analysis-coming {
    opacity: 0.7;
}

.analysis-coming h3 {
    color: var(--color-text-muted);
}

/* Hypothesis Section */
.hypothesis-template {
    background: var(--color-bg-secondary);
    padding: var(--spacing-md);
    border-radius: var(--border-radius);
    border: 1px solid var(--color-border);
}

.hypothesis-block {
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-md);
    border-bottom: 1px solid var(--color-border);
}

.hypothesis-block:last-child {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

.hypothesis-block h3 {
    font-size: 1.1rem;
    margin-bottom: var(--spacing-sm);
    color: var(--color-accent);
}

.hypothesis-block p {
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-sm);
    font-size: 0.95rem;
}

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

.hypothesis-inputs label {
    font-size: 0.9rem;
    color: var(--color-text);
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.hypothesis-inputs input {
    padding: var(--spacing-xs) var(--spacing-sm);
    background: var(--color-bg-tertiary);
    border: 1px solid var(--color-border);
    border-radius: 4px;
    color: var(--color-text);
    font-size: 0.9rem;
}

.hypothesis-inputs input:focus {
    outline: none;
    border-color: var(--color-accent);
}

/* Contact Section */
.contact-info {
    background: var(--color-bg-secondary);
    padding: var(--spacing-md);
    border-radius: var(--border-radius);
    border: 1px solid var(--color-border);
    text-align: center;
}

.contact-info p {
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-sm);
}

/* Footer */
.site-footer {
    background: var(--color-bg-secondary);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-lg) var(--spacing-md);
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    text-align: center;
}

.footer-content p {
    color: var(--color-text-muted);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-xs);
}

.footer-disclaimer {
    font-size: 0.8rem;
    opacity: 0.7;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--color-bg);
        flex-direction: column;
        padding: var(--spacing-md);
        border-bottom: 1px solid var(--color-border);
    }

    .nav-links.active {
        display: flex;
    }

    .mobile-menu-toggle {
        display: flex;
    }

    .hero {
        grid-template-columns: 1fr;
        padding-top: calc(80px + var(--spacing-lg));
    }

    .hero-content {
        padding-right: 0;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-cta {
        flex-direction: column;
    }

    .section-title {
        font-size: 1.5rem;
    }

    .philosophy-grid,
    .analysis-grid {
        grid-template-columns: 1fr;
    }

    .case-footer {
        flex-direction: column;
        gap: var(--spacing-sm);
        align-items: flex-start;
    }
}