/* 
  =========================================
  DESIGN SYSTEM: 観る者として生きる (Observer)
  =========================================
*/

/* Google Fonts Import */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600&family=JetBrains+Mono:wght@400;500&family=Outfit:wght@400;500;600;700&display=swap');

:root {
  /* Colors */
  --bg-primary: #ffffff;      /* Pure white for absolute clarity */
  --bg-secondary: #f8f9fa;    /* Clean, soft off-white for sections/cards */
  --bg-tertiary: #f1f3f5;     /* Light gray for buttons/interactive elements */
  
  --text-primary: #1e293b;     /* Slate-900: Soft dark text, easy on the eyes */
  --text-secondary: #475569;   /* Slate-600: Subdued text for metadata & descriptions */
  --text-muted: #94a3b8;       /* Slate-400: Muted borders and placeholders */
  
  --accent: #1e3a8a;           /* Deep navy blue - trust, safety, and cold observation */
  --accent-rgb: 30, 58, 138;
  --accent-dim: #172554;
  --accent-safe: #059669;      /* Emerald green for safety state */
  --accent-freeze: #2563eb;    /* Royal blue for freeze/dissociation state */
  
  --border: #e2e8f0;           /* Slate-200: Soft gray borders */
  --border-focus: #cbd5e1;     /* Slate-300: Focused border state */
  
  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-display: 'Outfit', var(--font-sans);
  --font-mono: 'JetBrains Mono', monospace;
  
  /* Layout */
  --max-width-content: 720px;
  --max-width-wide: 960px;
  --spacing-unit: 1.5rem;
}

/* Base Reset */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  background-color: var(--bg-primary);
}

/* Typography Elements */
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 500;
  line-height: 1.3;
  color: var(--text-primary);
  letter-spacing: 0;
}

h1 {
  font-size: 2.25rem;
  margin-bottom: 2rem;
  font-weight: 600;
  color: var(--accent);
}

h2 {
  font-size: 1.5rem;
  margin-top: 3.5rem;
  margin-bottom: 1.5rem;
  border-left: 3px solid var(--accent);
  padding-left: 1rem;
}

h3 {
  font-size: 1.2rem;
  margin-top: 2rem;
  margin-bottom: 1rem;
}

p {
  margin-bottom: 1.5rem;
  color: var(--text-primary);
  font-weight: 300;
}

p.lead {
  font-size: 1.1rem;
  line-height: 1.8;
  color: var(--text-secondary);
}

strong {
  font-weight: 500;
  color: var(--text-primary);
}

em {
  font-style: normal;
  color: var(--accent);
  font-weight: 500;
}

a {
  color: var(--accent);
  text-decoration: underline;
  text-decoration-color: var(--border-focus);
  text-underline-offset: 4px;
  transition: all 0.2s ease;
}

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

/* List Styling */
ul, ol {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
}

li {
  margin-bottom: 0.5rem;
  font-weight: 300;
}

li::marker {
  color: var(--accent);
}

/* Structural Components */
header {
  border-bottom: 1px solid var(--border);
  padding: 1.1rem 0;
  background-color: rgba(255, 255, 255, 0.85);
  position: sticky;
  top: 0;
  z-index: 1000;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.container {
  width: 100%;
  max-width: var(--max-width-content);
  margin: 0 auto;
  padding: 0 var(--spacing-unit);
}

.container-wide {
  width: 100%;
  max-width: var(--max-width-wide);
  margin: 0 auto;
  padding: 0 var(--spacing-unit);
}

main {
  flex: 1;
  padding: 3rem 0 6rem;
}

footer {
  border-top: 1px solid var(--border);
  padding: 3rem 0;
  background-color: var(--bg-secondary);
  color: var(--text-secondary);
  font-size: 0.85rem;
  font-family: var(--font-mono);
}

footer a {
  color: var(--text-secondary);
  text-decoration: none;
}

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

/* Callout Box (Alerts) */
.callout {
  background-color: var(--bg-secondary);
  border-left: 3px solid var(--accent);
  padding: 1.5rem;
  margin: 2rem 0;
  border-radius: 0 4px 4px 0;
  border: 1px solid var(--border);
  border-left-width: 3px;
}

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

.notice {
  background-color: #f8fafc;
  border: 1px solid var(--border);
  border-left: 3px solid var(--text-muted);
  border-radius: 0 4px 4px 0;
  padding: 1rem 1.25rem;
  margin: 1.75rem 0;
  font-size: 0.86rem;
}

.notice-title {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
  letter-spacing: 0;
}

.notice p {
  color: var(--text-secondary);
  margin-bottom: 0;
}

/* Manifesto Section Highlight */
.manifesto-quote {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 400;
  line-height: 1.6;
  border-left: 3px solid var(--accent);
  padding-left: 1.5rem;
  margin: 2.5rem 0;
  color: var(--text-secondary);
  letter-spacing: 0;
  overflow-wrap: anywhere;
}

.eyebrow,
.section-kicker {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-muted);
  letter-spacing: 0;
  margin-bottom: 0.85rem;
}

.author-line {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin: -0.75rem 0 1.5rem;
}

.author-line strong {
  color: var(--accent);
  font-weight: 500;
}

.author-panel {
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  padding: 1.75rem 0;
  margin: 2.5rem 0 1rem;
}

.author-panel h2 {
  border-left: 0;
  padding-left: 0;
  margin-top: 0;
  margin-bottom: 1rem;
}

.author-panel p {
  color: var(--text-secondary);
  margin-bottom: 0;
  overflow-wrap: anywhere;
}

/* Cards & Grid Layout */
.card-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  margin: 2rem 0;
}

@media (min-width: 640px) {
  .card-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.card {
  background-color: var(--bg-primary);
  border: 1px solid var(--border);
  padding: 1.35rem;
  border-radius: 4px;
  transition: all 0.2s ease;
}

.card:hover {
  border-color: var(--border-focus);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.02);
}

.card h3 {
  margin-top: 0;
  margin-bottom: 0.75rem;
  font-size: 1.15rem;
  color: var(--accent);
}

.card h3 a {
  text-decoration: none;
}

.card p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 0;
}

.card-primary {
  border-color: rgba(var(--accent-rgb), 0.35);
  background: linear-gradient(180deg, #ffffff 0%, #f8fafc 100%);
}

.toc-box {
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: 0 4px 4px 0;
  padding: 1.2rem 1.35rem;
  margin: 2rem 0 2.5rem;
  background-color: var(--bg-secondary);
}

.toc-box ol {
  margin-bottom: 0;
}

.toc-box li:last-child {
  margin-bottom: 0;
}

.faq-list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.75rem;
  margin: 2rem 0;
}

.faq-list details {
  border: 1px solid var(--border);
  border-radius: 4px;
  background-color: var(--bg-primary);
  padding: 1rem 1.1rem;
}

.faq-list summary {
  cursor: pointer;
  font-weight: 500;
  color: var(--text-primary);
}

.faq-list p {
  color: var(--text-secondary);
  margin: 1rem 0 0;
}

/* Interactive Component: Self-Check UI */
.diagnostic-widget {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 2rem;
  margin: 3rem 0;
}

.diagnostic-step {
  display: none;
}

.diagnostic-step.active {
  display: block;
}

.diagnostic-progress {
  display: flex;
  justify-content: space-between;
  margin-bottom: 1.5rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
}

.btn-group {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

.btn {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  border: 1px solid var(--border);
  padding: 1rem;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 400;
  text-align: left;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.btn:hover {
  background-color: var(--bg-tertiary);
  border-color: var(--border-focus);
}

.btn-primary {
  background-color: var(--accent);
  border-color: var(--accent);
  color: #ffffff;
  text-align: center;
  justify-content: center;
}

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

/* Diagnostic Results Styling */
.result-header {
  font-family: var(--font-display);
  font-size: 1.4rem;
  margin-bottom: 1rem;
  color: var(--accent);
}

.result-badge {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  border-radius: 9999px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  margin-bottom: 1.5rem;
}

.result-badge.safe {
  background-color: rgba(5, 150, 105, 0.1);
  color: var(--accent-safe);
  border: 1px solid rgba(5, 150, 105, 0.2);
}

.result-badge.fight-flight {
  background-color: rgba(30, 58, 138, 0.05);
  color: var(--accent);
  border: 1px solid rgba(30, 58, 138, 0.15);
}

.result-badge.freeze {
  background-color: rgba(37, 99, 235, 0.08);
  color: var(--accent-freeze);
  border: 1px solid rgba(37, 99, 235, 0.15);
}

/* Nav Menu */
.nav-menu {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  max-width: var(--max-width-wide);
}

.logo {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.15rem;
  text-decoration: none;
  color: var(--text-primary);
  letter-spacing: 0;
}

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

.nav-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 1.5rem;
  list-style: none;
  padding-left: 0;
  margin-bottom: 0;
  font-family: var(--font-mono);
  font-size: 0.8rem;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-secondary);
}

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

.nav-links a.active {
  font-weight: 500;
  border-bottom: 1px solid var(--accent);
  padding-bottom: 1px;
}

/* Back Link */
.back-link {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  margin-bottom: 2rem;
  display: inline-flex;
  align-items: center;
  text-decoration: none;
}

.back-link::before {
  content: '← ';
  margin-right: 0.5rem;
}

/* Metadata Text */
.meta-info {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 2rem;
}

/* Image Diagram Styling */
.diagram-container {
  margin: 3rem 0;
  text-align: center;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.5rem;
  background-color: var(--bg-secondary);
}

.diagram-img {
  max-width: 100%;
  height: auto;
  border-radius: 4px;
  display: block;
  margin: 0 auto;
}

.diagram-caption {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-top: 1rem;
  display: block;
  line-height: 1.5;
}

/* Mobile: nav wraps cleanly on small screens */
@media (max-width: 640px) {
  header {
    position: static;
  }

  .manifesto-quote {
    padding-left: 1rem;
  }

  .nav-menu {
    justify-content: center;
  }

  .nav-links {
    width: 100%;
    justify-content: center;
    gap: 0.75rem;
    font-size: 0.7rem;
  }

  .logo {
    font-size: 1rem;
  }
}

/* Hero Section */
.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 3rem;
  align-items: center;
  padding: 4.25rem var(--spacing-unit) 3.75rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 2rem;
  max-width: var(--max-width-wide);
}

.hero-content h1 {
  font-size: 2.9rem;
  line-height: 1.25;
  margin-bottom: 1.5rem;
  color: var(--accent);
}

.hero-content .lead {
  max-width: 34rem;
}

.hero-image-wrapper {
  position: relative;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 18px 44px rgba(15, 23, 42, 0.08);
  border: 1px solid var(--border);
  background: var(--bg-secondary);
}

.hero-image {
  width: 100%;
  height: auto;
  display: block;
  transition: transform 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.hero-image-wrapper:hover .hero-image {
  transform: scale(1.04);
}

/* Card Hover Upgrade */
.card {
  transition: transform 0.4s cubic-bezier(0.16, 1, 0.3, 1), border-color 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
  transform: translateY(-4px);
  border-color: var(--accent);
  box-shadow: 0 15px 30px rgba(30, 58, 138, 0.05);
}

/* Diagnostic Widget styling upgrade */
.diagnostic-widget {
  border-radius: 12px;
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.02);
}

.btn {
  transition: transform 0.2s cubic-bezier(0.16, 1, 0.3, 1), background-color 0.2s ease, border-color 0.2s ease;
}

.btn:hover {
  transform: translateX(4px);
}

.btn-primary:hover {
  transform: none;
}

/* Responsive adjustments */
@media (max-width: 768px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 2.5rem;
    padding: 2.5rem var(--spacing-unit) 2rem;
    text-align: center;
  }
  
  .hero-content h1 {
    font-size: 2.2rem;
  }

  .hero-content .lead {
    max-width: none;
  }
  
  .hero-image-wrapper {
    max-width: 320px;
    margin: 0 auto;
  }
}