/* ============================================
   COSMO - Research Paper Aesthetic
   Clean, Modern, Academic
   ============================================ */

/* ============================================
   CSS VARIABLES
   ============================================ */
   :root {
    /* Clean Paper Palette */
    --color-bg: #fafafa;
    --color-bg-card: #ffffff;
    --color-bg-elevated: #f8f9fb;
    --color-bg-accent: #f0f4f8;
    --color-text: #1a1a2e;
    --color-text-muted: #4a5568;
    --color-text-dim: #718096;
    --color-primary: #2d5a7b;
    --color-primary-light: #3d7a9e;
    --color-primary-dark: #1e3a5f;
    --color-accent: #0891b2;
    --color-accent-dim: rgba(8, 145, 178, 0.08);
    --color-border: #e2e8f0;
    --color-border-light: #edf2f7;
    --color-success: #059669;
    --color-warning: #d97706;
    
    /* Typography */
    --font-serif: 'Crimson Pro', 'Georgia', serif;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
    
    /* Spacing */
    --container-max: 900px;
    --container-wide: 1100px;
    --section-padding: 4rem;
    
    /* Effects */
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
    --shadow-lg: 0 8px 24px rgba(0,0,0,0.1);
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
}

/* ============================================
   RESET & BASE
   ============================================ */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.7;
    color: var(--color-text);
    background: var(--color-bg);
    min-height: 100vh;
}

/* ============================================
   TYPOGRAPHY
   ============================================ */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-serif);
    font-weight: 600;
    line-height: 1.3;
    color: var(--color-text);
}

h1 { font-size: 2.75rem; letter-spacing: -0.02em; }
h2 { font-size: 1.875rem; letter-spacing: -0.01em; }
h3 { font-size: 1.25rem; }
h4 { font-size: 1.1rem; }

p {
    color: var(--color-text-muted);
    text-align: left;
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-primary-light);
}

/* ============================================
   LAYOUT
   ============================================ */
.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 2rem;
}

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

/* ============================================
   NAVIGATION
   ============================================ */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border);
}

.nav-container {
    max-width: var(--container-wide);
    margin: 0 auto;
    padding: 0.875rem 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-family: var(--font-sans);
    font-weight: 600;
    color: var(--color-text);
    text-decoration: none;
}

.logo-icon {
    font-size: 1.5rem;
    color: var(--color-primary);
}

.logo-text {
    font-size: 1.125rem;
    letter-spacing: 0.08em;
}

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

.nav-links a {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--color-text-muted);
    transition: color var(--transition-fast);
    position: relative;
}

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

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-primary);
    transition: width var(--transition-fast);
}

.nav-links a:hover::after {
    width: 100%;
}

.nav-links a.nav-highlight {
    background: var(--color-accent-dim);
    border: 1px solid rgba(8, 145, 178, 0.2);
    padding: 0.35rem 0.85rem;
    border-radius: 100px;
    color: var(--color-accent);
    font-weight: 600;
}

.nav-links a.nav-highlight::after {
    display: none;
}

.nav-links a.nav-highlight:hover {
    background: rgba(8, 145, 178, 0.15);
    color: var(--color-accent);
}

/* Active nav state */
.nav-links a.active {
    color: var(--color-text);
}

.nav-links a.active::after {
    width: 100%;
}

/* ============================================
   NAVIGATION DROPDOWN
   ============================================ */
.nav-dropdown {
    position: relative;
}

.nav-dropdown-toggle {
    display: flex;
    align-items: center;
    gap: 0.35rem;
    cursor: pointer;
}

.dropdown-arrow {
    font-size: 0.65rem;
    transition: transform var(--transition-fast);
}

.nav-dropdown:hover .dropdown-arrow {
    transform: rotate(180deg);
}

.nav-dropdown-menu {
    position: absolute;
    top: calc(100% + 0.75rem);
    right: 0;
    min-width: 220px;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: 8px;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: all var(--transition-fast);
    z-index: 200;
    overflow: hidden;
}

.nav-dropdown:hover .nav-dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.nav-dropdown-menu a {
    display: flex;
    align-items: center;
    gap: 0.875rem;
    padding: 0.875rem 1rem;
    border-bottom: 1px solid var(--color-border-light);
    transition: background var(--transition-fast);
}

.nav-dropdown-menu a:last-child {
    border-bottom: none;
}

.nav-dropdown-menu a:hover {
    background: var(--color-bg-elevated);
}

.nav-dropdown-menu a::after {
    display: none;
}

.dropdown-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    background: var(--color-bg-elevated);
    border: 1px solid var(--color-border);
    border-radius: 6px;
    font-size: 0.8rem;
    color: var(--color-primary);
    flex-shrink: 0;
}

.dropdown-text,
.dropdown-label {
    display: flex;
    flex-direction: column;
    gap: 0.125rem;
}

.dropdown-text strong,
.dropdown-label strong {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--color-text);
}

.dropdown-desc {
    font-size: 0.7rem;
    color: var(--color-text-dim);
    font-weight: 400;
}

.nav-dropdown-menu a.active .dropdown-icon {
    background: var(--color-primary);
    border-color: var(--color-primary);
    color: white;
}

.nav-dropdown-menu a.active .dropdown-label strong {
    color: var(--color-primary);
}

/* ============================================
   HERO SECTION
   ============================================ */
.hero {
    padding: 8rem 0 4rem;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
}

.hero-container {
    max-width: var(--container-wide);
    margin: 0 auto;
    padding: 0 2rem;
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 4rem;
    align-items: center;
}

.hero-badge {
    display: inline-block;
    padding: 0.375rem 1rem;
    background: var(--color-accent-dim);
    border: 1px solid rgba(8, 145, 178, 0.2);
    border-radius: 100px;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-accent);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: 1.5rem;
}

.hero-title {
    font-family: var(--font-serif);
    font-size: 2.5rem;
    font-weight: 600;
    line-height: 1.2;
    margin-bottom: 1.5rem;
    letter-spacing: -0.02em;
}

.title-line {
    display: block;
}

.title-line.accent {
    color: var(--color-primary);
}

.hero-subtitle {
    font-size: 1.125rem;
    color: var(--color-text-muted);
    line-height: 1.8;
    margin-bottom: 2rem;
    max-width: 540px;
}

.hero-actions {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

/* ============================================
   BUTTONS
   ============================================ */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.75rem;
    font-size: 0.9rem;
    font-weight: 500;
    border-radius: 6px;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
    border: none;
}

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

.btn-primary:hover {
    background: var(--color-primary-dark);
    box-shadow: var(--shadow-md);
    color: white;
    transform: translateY(-1px);
}

.btn-secondary {
    background: transparent;
    color: var(--color-primary);
    border: 1px solid var(--color-primary);
}

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

/* ============================================
   HERO VISUAL - ORBIT SYSTEM
   ============================================ */
.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
}

.orbit-system {
    position: relative;
    width: 280px;
    height: 280px;
}

.orbit {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    border: 1px solid var(--color-border);
    border-radius: 50%;
    opacity: 0.6;
}

.orbit-1 { width: 90px; height: 90px; }
.orbit-2 { width: 160px; height: 160px; }
.orbit-3 { width: 230px; height: 230px; }

.core-node {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 56px;
    height: 56px;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.7rem;
    font-weight: 600;
    color: white;
    box-shadow: 0 4px 20px rgba(45, 90, 123, 0.3);
}

.satellite {
    position: absolute;
    width: 26px;
    height: 26px;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.7rem;
    color: var(--color-primary);
    box-shadow: var(--shadow-sm);
    animation: float 4s ease-in-out infinite;
}

.sat-1 { top: 50%; left: calc(50% + 45px); transform: translate(-50%, -50%); animation-delay: 0s; }
.sat-2 { top: calc(50% - 56px); left: calc(50% + 56px); transform: translate(-50%, -50%); animation-delay: 0.5s; }
.sat-3 { top: calc(50% - 80px); left: 50%; transform: translate(-50%, -50%); animation-delay: 1s; }
.sat-4 { top: calc(50% + 56px); left: calc(50% - 56px); transform: translate(-50%, -50%); animation-delay: 1.5s; }
.sat-5 { top: 50%; left: calc(50% - 115px); transform: translate(-50%, -50%); animation-delay: 2s; }

@keyframes float {
    0%, 100% { opacity: 0.7; }
    50% { opacity: 1; }
}

/* ============================================
   SECTION HEADERS
   ============================================ */
.section-header {
    text-align: center;
    margin-bottom: 3rem;
}

.section-label {
    display: inline-block;
    font-family: var(--font-sans);
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--color-primary);
    margin-bottom: 0.75rem;
}

.section-header h2 {
    font-size: 2rem;
}

/* Section divider */
.section::after {
    content: '§';
    display: block;
    text-align: center;
    font-size: 1.25rem;
    color: var(--color-border);
    margin-top: 3rem;
}

.section:last-of-type::after {
    display: none;
}

/* ============================================
   OVERVIEW SECTION
   ============================================ */
.overview-grid {
    display: grid;
    grid-template-columns: 1.5fr 1fr;
    gap: 3rem;
    align-items: start;
}

.overview-content .lead {
    font-size: 1.125rem;
    color: var(--color-text);
    margin-bottom: 1rem;
    line-height: 1.8;
}

.overview-content p {
    margin-bottom: 1.5rem;
    line-height: 1.8;
}

.key-insight {
    display: flex;
    gap: 1rem;
    padding: 1.5rem;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-left: 4px solid var(--color-primary);
    border-radius: 0 8px 8px 0;
}

.insight-icon {
    font-size: 1.5rem;
    color: var(--color-primary);
}

.insight-content strong {
    display: block;
    font-family: var(--font-sans);
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-primary);
    margin-bottom: 0.5rem;
}

.insight-content p {
    font-size: 0.95rem;
    margin: 0;
    font-style: italic;
}

.overview-stats {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.stat-card {
    padding: 1.5rem;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: 8px;
    text-align: center;
    transition: box-shadow var(--transition-fast);
}

.stat-card:hover {
    box-shadow: var(--shadow-md);
}

.stat-number {
    font-family: var(--font-serif);
    font-size: 2.5rem;
    font-weight: 600;
    color: var(--color-primary);
    line-height: 1;
    margin-bottom: 0.25rem;
}

.stat-label {
    font-size: 0.8rem;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* ============================================
   PRINCIPLES SECTION
   ============================================ */
.section-principles {
    background: var(--color-bg-elevated);
}

.principles-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
    max-width: var(--container-wide);
    margin: 0 auto;
}

.principle-card {
    padding: 1.75rem;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: 8px;
    transition: all var(--transition-base);
}

.principle-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.principle-number {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: 0.75rem;
}

.principle-card h3 {
    font-family: var(--font-sans);
    font-size: 1.05rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.principle-card p {
    font-size: 0.9rem;
    line-height: 1.6;
}

/* ============================================
   ARCHITECTURE SECTION
   ============================================ */
.arch-intro {
    text-align: center;
    max-width: 700px;
    margin: 0 auto 2.5rem;
    color: var(--color-text-muted);
    font-size: 1.05rem;
    line-height: 1.8;
}

.arch-diagram {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    max-width: var(--container-wide);
    margin: 0 auto;
}

.arch-layer {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    padding: 1rem 1.5rem;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: 6px;
    transition: all var(--transition-fast);
}

.arch-layer:hover {
    box-shadow: var(--shadow-sm);
}

.layer-label {
    min-width: 220px;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--color-text-dim);
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.layer-modules {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.module-tag {
    padding: 0.3rem 0.75rem;
    background: var(--color-bg-elevated);
    border: 1px solid var(--color-border);
    border-radius: 4px;
    font-size: 0.75rem;
    font-family: var(--font-mono);
    color: var(--color-text-muted);
}

.module-tag.highlight {
    background: rgba(45, 90, 123, 0.08);
    border-color: rgba(45, 90, 123, 0.2);
    color: var(--color-primary);
    font-weight: 500;
}

.module-tag.accent {
    background: rgba(8, 145, 178, 0.08);
    border-color: rgba(8, 145, 178, 0.2);
    color: var(--color-accent);
}

.layer-core {
    border-color: var(--color-primary);
    border-width: 2px;
    background: rgba(45, 90, 123, 0.02);
}

.layer-substrate {
    border-color: var(--color-accent);
    background: rgba(8, 145, 178, 0.02);
}

/* ============================================
   MECHANISMS SECTION
   ============================================ */
.section-mechanisms {
    background: var(--color-bg-elevated);
}

.mechanisms-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
    max-width: var(--container-wide);
    margin: 0 auto;
}

.mechanism-card {
    padding: 1.75rem;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: 8px;
    transition: all var(--transition-base);
}

.mechanism-card:hover {
    box-shadow: var(--shadow-md);
}

.mechanism-icon {
    font-size: 1.5rem;
    color: var(--color-primary);
    margin-bottom: 1rem;
}

.mechanism-card h3 {
    font-family: var(--font-sans);
    font-size: 1.05rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.mechanism-card p {
    font-size: 0.9rem;
    line-height: 1.6;
    margin-bottom: 1rem;
}

.mechanism-meta {
    padding-top: 0.75rem;
    border-top: 1px solid var(--color-border);
}

.mechanism-meta span {
    font-size: 0.75rem;
    font-family: var(--font-mono);
    color: var(--color-text-dim);
}

/* ============================================
   AGENTS SECTION
   ============================================ */
.agents-grid {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 0.75rem;
    max-width: var(--container-wide);
    margin: 0 auto;
}

.agent-card {
    padding: 1rem 0.75rem;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: 8px;
    text-align: center;
    transition: all var(--transition-fast);
}

.agent-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
    border-color: var(--color-primary);
}

.agent-icon {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.agent-card h4 {
    font-family: var(--font-sans);
    font-size: 0.75rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.agent-card p {
    font-size: 0.65rem;
    color: var(--color-text-dim);
    line-height: 1.4;
}

/* ============================================
   FEATURES SECTION
   ============================================ */
.section-features {
    background: var(--color-bg-elevated);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
    max-width: var(--container-wide);
    margin: 0 auto;
}

.feature-card {
    padding: 1.75rem;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: 8px;
}

.feature-card h3 {
    font-family: var(--font-sans);
    font-size: 1.05rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.feature-card h3::before {
    content: '→';
    color: var(--color-primary);
    font-weight: 400;
}

.feature-card p {
    font-size: 0.9rem;
    line-height: 1.6;
}

/* ============================================
   TECH SECTION
   ============================================ */
.tech-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
    max-width: var(--container-wide);
    margin: 0 auto;
}

.tech-category {
    padding: 1.5rem;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: 8px;
}

.tech-category h3 {
    font-family: var(--font-sans);
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--color-primary);
    margin-bottom: 1rem;
    padding-bottom: 0.75rem;
    border-bottom: 2px solid var(--color-primary);
}

.tech-category ul {
    list-style: none;
}

.tech-category li {
    display: flex;
    justify-content: space-between;
    padding: 0.5rem 0;
    font-size: 0.875rem;
    border-bottom: 1px solid var(--color-border-light);
}

.tech-category li:last-child {
    border-bottom: none;
}

.tech-category li span:first-child {
    color: var(--color-text-muted);
}

.tech-category li span:last-child {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--color-text);
}

/* ============================================
   CTA SECTION
   ============================================ */
.section-cta {
    background: var(--color-bg-card);
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
    padding: 3rem 0;
}

.section-cta::after {
    display: none;
}

.cta-content {
    text-align: center;
    max-width: 600px;
    margin: 0 auto;
}

.cta-content h2 {
    font-size: 1.75rem;
    margin-bottom: 1rem;
}

.cta-content p {
    font-size: 1rem;
    margin-bottom: 1.5rem;
    text-align: center;
    line-height: 1.8;
}

.cta-meta {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.version-badge,
.date-badge {
    padding: 0.5rem 1rem;
    background: var(--color-bg-elevated);
    border: 1px solid var(--color-border);
    border-radius: 100px;
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--color-text-muted);
}

.version-badge {
    border-color: var(--color-primary);
    color: var(--color-primary);
}

/* ============================================
   FOOTER
   ============================================ */
.footer {
    padding: 2.5rem 0;
    background: var(--color-bg);
    border-top: 1px solid var(--color-border);
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    text-align: center;
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
}

.footer-brand .logo-icon {
    font-size: 1.25rem;
}

.footer-content p {
    font-size: 0.85rem;
    color: var(--color-text-dim);
}

.footer-social {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    margin-top: 0.75rem;
    padding: 0.5rem 1rem;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: 100px;
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--color-text-muted);
    transition: all var(--transition-fast);
}

.footer-social:hover {
    color: var(--color-text);
    border-color: var(--color-primary);
    box-shadow: var(--shadow-sm);
}

.footer-social svg {
    flex-shrink: 0;
}

/* ============================================
   MOBILE NAVIGATION
   ============================================ */
.nav-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    z-index: 101;
}

.hamburger {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--color-text);
    position: relative;
    transition: background 0.2s ease;
}

.hamburger::before,
.hamburger::after {
    content: '';
    position: absolute;
    width: 24px;
    height: 2px;
    background: var(--color-text);
    left: 0;
    transition: transform 0.3s ease, top 0.3s ease;
}

.hamburger::before { top: -7px; }
.hamburger::after { top: 7px; }

.nav-toggle-active .hamburger {
    background: transparent;
}

.nav-toggle-active .hamburger::before {
    top: 0;
    transform: rotate(45deg);
    background: var(--color-primary);
}

.nav-toggle-active .hamburger::after {
    top: 0;
    transform: rotate(-45deg);
    background: var(--color-primary);
}

/* Scroll Animations */
.animate-target {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.5s ease, transform 0.5s ease;
}

.animate-target.animate-in {
    opacity: 1;
    transform: translateY(0);
}

/* Focus States */
.btn:focus-visible,
.nav-links a:focus-visible,
.nav-toggle:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* ============================================
   RESPONSIVE - TABLET
   ============================================ */
@media (max-width: 1024px) {
    .nav-toggle {
        display: block;
    }
    
    .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 280px;
        height: 100vh;
        background: var(--color-bg-card);
        flex-direction: column;
        padding: 5rem 2rem 2rem;
        gap: 0;
        box-shadow: -4px 0 20px rgba(0,0,0,0.1);
        transition: right 0.3s ease;
        z-index: 100;
    }
    
    .nav-links.nav-open {
        right: 0;
    }
    
    .nav-links a {
        display: block;
        padding: 1rem 0;
        font-size: 1rem;
        border-bottom: 1px solid var(--color-border);
    }
    
    .nav-links a::after {
        display: none;
    }
    
    /* Mobile dropdown */
    .nav-dropdown {
        width: 100%;
    }
    
    .nav-dropdown-toggle {
        width: 100%;
        justify-content: space-between;
    }
    
    .nav-dropdown-menu {
        position: static;
        transform: none;
        opacity: 1;
        visibility: visible;
        box-shadow: none;
        border: none;
        background: var(--color-bg-elevated);
        margin: 0.5rem 0;
        border-radius: 8px;
    }
    
    .nav-dropdown-menu a {
        border-bottom: none;
        padding: 0.75rem 1rem;
    }
    
    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero-subtitle {
        max-width: 100%;
        margin-left: auto;
        margin-right: auto;
    }
    
    .hero-actions {
        justify-content: center;
    }
    
    .hero-visual {
        margin-top: 2rem;
    }
    
    .orbit-system {
        width: 200px;
        height: 200px;
    }
    
    .orbit-1 { width: 60px; height: 60px; }
    .orbit-2 { width: 115px; height: 115px; }
    .orbit-3 { width: 170px; height: 170px; }
    
    .core-node {
        width: 40px;
        height: 40px;
        font-size: 0.6rem;
    }
    
    .satellite {
        width: 20px;
        height: 20px;
        font-size: 0.6rem;
    }
    
    .sat-1 { left: calc(50% + 30px); }
    .sat-2 { top: calc(50% - 40px); left: calc(50% + 40px); }
    .sat-3 { top: calc(50% - 57px); }
    .sat-4 { top: calc(50% + 40px); left: calc(50% - 40px); }
    .sat-5 { left: calc(50% - 85px); }
    
    .overview-grid {
        grid-template-columns: 1fr;
    }
    
    .overview-stats {
        flex-direction: row;
        justify-content: center;
    }
    
    .stat-card {
        flex: 1;
        max-width: 150px;
    }
    
    .principles-grid,
    .mechanisms-grid,
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .agents-grid {
        grid-template-columns: repeat(4, 1fr);
    }
    
    .tech-grid {
        grid-template-columns: 1fr;
    }
    
    .arch-layer {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }
    
    .layer-label {
        min-width: auto;
    }
}

/* ============================================
   RESPONSIVE - MOBILE
   ============================================ */
@media (max-width: 640px) {
    body {
        font-size: 15px;
    }
    
    .container {
        padding: 0 1.25rem;
    }
    
    .section {
        padding: 2.5rem 0;
    }
    
    h1 { font-size: 1.75rem; }
    h2 { font-size: 1.5rem; }
    
    .nav-container {
        padding: 0.75rem 1.25rem;
    }
    
    .nav-links {
        width: 100%;
    }
    
    .hero {
        padding: 5rem 0 2.5rem;
    }
    
    .hero-title {
        font-size: 1.75rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
    }
    
    .hero-actions {
        flex-direction: column;
        gap: 0.75rem;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
    
    .hero-visual {
        display: none;
    }
    
    .overview-stats {
        flex-direction: column;
    }
    
    .stat-card {
        max-width: 100%;
    }
    
    .key-insight {
        flex-direction: column;
        text-align: center;
    }
    
    .principles-grid,
    .mechanisms-grid,
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .agents-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .section::after {
        margin-top: 2rem;
    }
}

/* ============================================
   RESPONSIVE - SMALL MOBILE
   ============================================ */
@media (max-width: 380px) {
    .agents-grid {
        grid-template-columns: 1fr;
    }
    
    .agent-card {
        display: flex;
        align-items: center;
        gap: 0.75rem;
        text-align: left;
        padding: 0.75rem;
    }
    
    .agent-icon {
        font-size: 1.5rem;
        margin-bottom: 0;
    }
}