/* ==========================================================================
   SUTNE — DESIGN SYSTEM & PRESENTATION STYLESHEET
   Based on DESIGN-SYSTEM.md & UX.md specifications
   ========================================================================== */

:root {
  /* Color Palette - Dark Theme (Default) */
  --bg-main: #090d14;
  --bg-surface: #101622;
  --bg-surface-elevated: #161e2e;
  --bg-surface-glass: rgba(16, 22, 34, 0.75);
  
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-strong: rgba(255, 255, 255, 0.16);
  --border-accent: rgba(56, 189, 248, 0.35);

  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --text-accent: #38bdf8;

  --accent-cyan: #06b6d4;
  --accent-cyan-glow: rgba(6, 182, 212, 0.25);
  --accent-emerald: #10b981;
  --accent-amber: #f59e0b;
  --accent-coral: #f43f5e;

  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;

  --shadow-card: 0 4px 20px -2px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 50px -10px var(--accent-cyan-glow);

  --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-smooth: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="light"] {
  --bg-main: #f8fafc;
  --bg-surface: #ffffff;
  --bg-surface-elevated: #f1f5f9;
  --bg-surface-glass: rgba(255, 255, 255, 0.85);

  --border-subtle: rgba(0, 0, 0, 0.08);
  --border-strong: rgba(0, 0, 0, 0.16);
  --border-accent: rgba(2, 132, 199, 0.4);

  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --text-accent: #0284c7;

  --shadow-card: 0 4px 20px -2px rgba(0, 0, 0, 0.06);
}

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

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-main);
  color: var(--text-primary);
  line-height: 1.65;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color var(--transition-smooth), color var(--transition-smooth);
}

/* Ambient glow */
.glow-bg {
  position: fixed;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 100vw;
  height: 100vh;
  background: radial-gradient(circle at 50% 15%, rgba(6, 182, 212, 0.12) 0%, rgba(9, 13, 20, 0) 65%);
  pointer-events: none;
  z-index: 0;
}

[data-theme="light"] .glow-bg {
  background: radial-gradient(circle at 50% 15%, rgba(2, 132, 199, 0.08) 0%, rgba(248, 250, 252, 0) 65%);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  position: relative;
  z-index: 1;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  width: 100%;
  background: var(--bg-surface-glass);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-subtle);
  z-index: 100;
}

.header-container {
  max-width: 1240px;
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--text-primary);
}

.brand-logo {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-full);
  object-fit: cover;
  border: 1.5px solid var(--border-strong);
  box-shadow: 0 0 12px rgba(6, 182, 212, 0.3);
}

.brand-name {
  font-size: 1.25rem;
  font-weight: 800;
  letter-spacing: 0.04em;
}

.brand-badge {
  font-size: 0.7rem;
  font-family: var(--font-mono);
  font-weight: 600;
  padding: 2px 8px;
  border-radius: var(--radius-full);
  background: rgba(56, 189, 248, 0.12);
  color: var(--text-accent);
  border: 1px solid var(--border-accent);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 20px;
}

.nav-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  transition: color var(--transition-fast);
}

.nav-link:hover,
.nav-link.active {
  color: var(--text-primary);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.theme-btn {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 1.1rem;
  transition: background var(--transition-fast), border-color var(--transition-fast);
}

.theme-btn:hover {
  border-color: var(--border-strong);
}

.mobile-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  flex-direction: column;
  gap: 5px;
  padding: 6px;
}

.mobile-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  transition: var(--transition-fast);
}

/* Hero Section */
.hero-section {
  padding: 90px 0 70px;
  text-align: center;
  position: relative;
}

.hero-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  max-width: 900px;
}

.hero-emblem-wrap {
  position: relative;
  margin-bottom: 28px;
}

.hero-emblem {
  width: 104px;
  height: 104px;
  border-radius: var(--radius-full);
  border: 2px solid var(--border-strong);
  box-shadow: 0 0 35px rgba(6, 182, 212, 0.45);
}

.hero-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-full);
  font-size: 0.825rem;
  font-family: var(--font-mono);
  color: var(--text-secondary);
  margin-bottom: 24px;
}

.pill-dot {
  width: 8px;
  height: 8px;
  background-color: var(--accent-cyan);
  border-radius: var(--radius-full);
  box-shadow: 0 0 8px var(--accent-cyan);
}

.hero-title {
  font-size: clamp(2.8rem, 6vw, 4.2rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.1;
  margin-bottom: 20px;
}

.hero-subtitle-gradient {
  display: block;
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 700;
  background: linear-gradient(135deg, #38bdf8 0%, #818cf8 50%, #c084fc 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-top: 6px;
}

.hero-lead {
  font-size: 1.2rem;
  color: var(--text-secondary);
  max-width: 780px;
  margin: 0 auto 36px;
  font-weight: 400;
}

.hero-thesis-box {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  background: var(--bg-surface-glass);
  border: 1px solid var(--border-subtle);
  backdrop-filter: blur(12px);
  padding: 14px 28px;
  border-radius: var(--radius-md);
  margin-bottom: 40px;
  box-shadow: var(--shadow-card);
}

.thesis-item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 0.875rem;
}

.thesis-label {
  color: var(--text-muted);
}

.thesis-arrow {
  color: var(--accent-cyan);
  font-weight: bold;
}

.thesis-val {
  color: var(--text-primary);
  font-weight: 600;
}

.thesis-divider {
  width: 1px;
  height: 20px;
  background: var(--border-subtle);
}

.hero-cta-group {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  justify-content: center;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 24px;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  min-height: 46px;
}

.btn-primary {
  background: linear-gradient(135deg, #0284c7 0%, #0369a1 100%);
  color: #ffffff;
  border: 1px solid rgba(56, 189, 248, 0.4);
  box-shadow: 0 4px 14px rgba(2, 132, 199, 0.35);
}

.btn-primary:hover {
  background: linear-gradient(135deg, #0369a1 0%, #075985 100%);
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(2, 132, 199, 0.45);
}

.btn-secondary {
  background: var(--bg-surface-elevated);
  color: var(--text-primary);
  border: 1px solid var(--border-subtle);
}

.btn-secondary:hover {
  background: var(--bg-surface);
  border-color: var(--border-strong);
}

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

.btn-outline:hover {
  color: var(--text-primary);
  border-color: var(--border-strong);
}

/* Sections */
.section {
  padding: 90px 0;
  position: relative;
  z-index: 1;
}

.section-darker {
  background-color: rgba(0, 0, 0, 0.25);
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
}

[data-theme="light"] .section-darker {
  background-color: rgba(0, 0, 0, 0.02);
}

.section-header {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 56px;
}

.section-kicker {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--text-accent);
  margin-bottom: 12px;
}

.section-title {
  font-size: clamp(2rem, 4vw, 2.6rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin-bottom: 16px;
}

.section-desc {
  font-size: 1.1rem;
  color: var(--text-secondary);
}

/* Grid */
.grid {
  display: grid;
  gap: 24px;
}

.grid-2 {
  grid-template-columns: repeat(auto-fit, minmax(360px, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-4 {
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

/* Cards */
.card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 28px;
  transition: transform var(--transition-fast), border-color var(--transition-fast);
  box-shadow: var(--shadow-card);
}

.card:hover {
  transform: translateY(-2px);
  border-color: var(--border-strong);
}

.card-icon {
  font-size: 2rem;
  margin-bottom: 16px;
}

.card-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 12px;
}

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

.highlight-card {
  background: linear-gradient(145deg, var(--bg-surface) 0%, rgba(6, 182, 212, 0.08) 100%);
  border-color: var(--border-accent);
}

/* Product Matrix */
.product-matrix {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.matrix-column {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 32px 24px;
}

.matrix-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 4px 10px;
  background: rgba(56, 189, 248, 0.1);
  color: var(--text-accent);
  border-radius: var(--radius-full);
  margin-bottom: 16px;
}

.matrix-column h4 {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.matrix-column p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* 6 Elements Flow */
.elements-flow {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

.element-node {
  flex: 1;
  min-width: 160px;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 20px 16px;
  box-shadow: var(--shadow-card);
}

.element-num {
  font-family: var(--font-mono);
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--accent-cyan);
  margin-bottom: 8px;
}

.element-body h4 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 6px;
}

.element-body p {
  font-size: 0.825rem;
  color: var(--text-secondary);
  line-height: 1.4;
}

.element-arrow {
  font-size: 1.4rem;
  color: var(--text-muted);
  font-weight: bold;
}

/* Boundaries */
.boundary-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 32px;
}

.boundary-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  padding: 4px 10px;
  border-radius: var(--radius-full);
  margin-bottom: 16px;
}

.boundary-card.negative .boundary-badge {
  background: rgba(244, 63, 94, 0.12);
  color: var(--accent-coral);
  border: 1px solid rgba(244, 63, 94, 0.3);
}

.boundary-card h4 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 12px;
}

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

/* Principles List */
.principles-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
  max-width: 900px;
  margin: 0 auto;
}

.principle-item {
  display: flex;
  gap: 20px;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 24px;
  align-items: flex-start;
  transition: border-color var(--transition-fast);
}

.principle-item:hover {
  border-color: var(--border-strong);
}

.principle-code {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
  padding: 4px 10px;
  background: rgba(6, 182, 212, 0.12);
  color: var(--text-accent);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-accent);
}

.principle-content h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 6px;
}

.principle-content p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* Architecture Cards */
.arch-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 28px;
}

.arch-tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--text-accent);
  margin-bottom: 12px;
}

.arch-card h4 {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 10px;
}

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

/* Roadmap Timeline */
.roadmap-timeline {
  display: flex;
  flex-direction: column;
  gap: 24px;
  max-width: 840px;
  margin: 0 auto;
  position: relative;
}

.timeline-step {
  display: flex;
  gap: 24px;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 28px;
}

.step-badge {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  padding: 6px 14px;
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  height: fit-content;
  white-space: nowrap;
}

.step-badge.active {
  background: rgba(16, 185, 129, 0.15);
  color: var(--accent-emerald);
  border-color: rgba(16, 185, 129, 0.4);
}

.step-body h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.step-meta {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent-cyan);
  margin-bottom: 10px;
}

.step-body p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* Actors */
.actor-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 24px;
  text-align: center;
}

.actor-icon {
  font-size: 2.2rem;
  margin-bottom: 12px;
}

.actor-card h4 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.actor-card p {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border-subtle);
  background: var(--bg-surface);
  padding: 50px 0;
  position: relative;
  z-index: 1;
}

.footer-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 30px;
}

.footer-logo-row {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 8px;
}

.footer-logo {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
}

.footer-brand-title {
  font-size: 1.15rem;
  font-weight: 800;
}

.footer-tagline {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

.footer-badges {
  display: flex;
  gap: 8px;
  margin-bottom: 8px;
  flex-wrap: wrap;
}

.badge {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: 2px 8px;
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-full);
  color: var(--text-secondary);
}

.footer-copyright {
  color: var(--text-muted);
  font-size: 0.8rem;
}

/* Responsive */
@media (max-width: 900px) {
  .product-matrix {
    grid-template-columns: 1fr;
  }

  .elements-flow {
    flex-direction: column;
  }

  .element-node {
    width: 100%;
  }

  .element-arrow {
    transform: rotate(90deg);
  }

  .nav-menu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background: var(--bg-surface);
    border-bottom: 1px solid var(--border-subtle);
    flex-direction: column;
    padding: 20px;
    gap: 16px;
  }

  .nav-menu.open {
    display: flex;
  }

  .mobile-toggle {
    display: flex;
  }

  .hero-thesis-box {
    flex-direction: column;
    gap: 10px;
  }

  .thesis-divider {
    display: none;
  }
}