/* ==========================================================================
   Reason & Form | Logic, Materials, and Engineered Systems
   Core Technical Design System & Layout
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:wght@400;500;600;700;800&family=JetBrains+Mono:wght@400;500;600&family=Newsreader:ital,opsz,wght@0,6..72,400;0,6..72,500;1,6..72,400&display=swap');

:root {
  /* Core Color Palette */
  --color-obsidian: #17181D;
  --color-indigo: #3F4A8A;
  --color-indigo-dark: #2C3566;
  --color-indigo-subtle: #EEF1FA;
  --color-indigo-border: #D1D8EE;
  
  --color-lime: #B6D84A;
  --color-lime-dark: #8BA92F;
  --color-lime-tint: rgba(182, 216, 74, 0.15);
  
  --color-amber: #E59C45;
  --color-amber-dark: #B97628;
  --color-amber-tint: rgba(229, 156, 69, 0.14);
  
  --color-paper: #F5F2EA;
  --color-paper-light: #FAF9F5;
  --color-paper-subtle: #EDE9DE;
  
  --color-fog: #E9EBF0;
  --color-fog-light: #F4F5F8;
  
  --color-graphite: #343840;
  --color-slate: #737984;
  --color-slate-light: #9DA3AF;
  --color-white: #FFFFFF;

  /* Typography */
  --font-sans: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-serif: 'Newsreader', Georgia, Cambria, serif;
  --font-mono: 'JetBrains Mono', 'SFMono-Regular', Consolas, Menlo, monospace;

  /* Layout & Sizing */
  --container-max: 1180px;
  --container-padding: 24px;
  --radius-xs: 4px;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 22px;
  --radius-pill: 9999px;

  /* Shadows & Elevation */
  --shadow-subtle: 0 1px 3px rgba(23, 24, 29, 0.05), 0 1px 2px rgba(23, 24, 29, 0.03);
  --shadow-card: 0 4px 12px rgba(23, 24, 29, 0.04), 0 1px 3px rgba(23, 24, 29, 0.03);
  --shadow-card-hover: 0 12px 24px rgba(23, 24, 29, 0.07), 0 2px 6px rgba(23, 24, 29, 0.04);
  --shadow-elevation: 0 16px 36px rgba(23, 24, 29, 0.09);

  /* Transitions */
  --transition-fast: 160ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 240ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-smooth: 350ms cubic-bezier(0.16, 1, 0.3, 1);

  /* Header Height */
  --header-height: 76px;
}

/* ==========================================================================
   Base & Reset
   ========================================================================== */

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--color-paper-light);
  color: var(--color-graphite);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

img,
svg {
  display: block;
  max-width: 100%;
}

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

button {
  font-family: inherit;
  border: none;
  background: none;
  cursor: pointer;
}

ul,
ol {
  list-style: none;
}

/* Accessibility Focus States */
:focus-visible {
  outline: 2px solid var(--color-indigo);
  outline-offset: 3px;
}

.skip-link {
  position: absolute;
  top: -60px;
  left: 20px;
  background: var(--color-obsidian);
  color: var(--color-lime);
  padding: 10px 18px;
  font-weight: 600;
  font-size: 0.9rem;
  border-radius: var(--radius-sm);
  z-index: 9999;
  transition: top var(--transition-fast);
  border: 1px solid var(--color-lime);
}

.skip-link:focus {
  top: 16px;
}

/* Container */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--container-padding);
  padding-right: var(--container-padding);
}

/* ==========================================================================
   Typography & Atomic Utilities
   ========================================================================== */

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-indigo);
  margin-bottom: 12px;
}

.eyebrow::before {
  content: '';
  display: inline-block;
  width: 7px;
  height: 7px;
  background-color: var(--color-lime);
  border-radius: 1px;
  transform: rotate(45deg);
}

.eyebrow--amber::before {
  background-color: var(--color-amber);
}

.eyebrow--obsidian {
  color: var(--color-slate-light);
}
.eyebrow--obsidian::before {
  background-color: var(--color-lime);
}

.section-title {
  font-family: var(--font-sans);
  font-size: clamp(1.85rem, 3.2vw, 2.65rem);
  font-weight: 700;
  color: var(--color-obsidian);
  line-height: 1.22;
  letter-spacing: -0.02em;
  margin-bottom: 14px;
}

.section-desc {
  font-size: 1.08rem;
  color: var(--color-slate);
  max-width: 680px;
  line-height: 1.65;
  margin-bottom: 36px;
}

.section-header {
  margin-bottom: 48px;
}

.section-header--center {
  text-align: center;
  margin-left: auto;
  margin-right: auto;
}
.section-header--center .section-desc {
  margin-left: auto;
  margin-right: auto;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 12px 22px;
  font-family: var(--font-sans);
  font-size: 0.94rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  transition: all var(--transition-base);
  line-height: 1.3;
  white-space: nowrap;
}

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

.btn-primary:hover {
  background-color: var(--color-indigo);
  border-color: var(--color-indigo);
  transform: translateY(-1px);
  box-shadow: 0 4px 14px rgba(63, 74, 138, 0.25);
}

.btn-secondary {
  background-color: transparent;
  color: var(--color-obsidian);
  border: 1px solid rgba(23, 24, 29, 0.24);
}

.btn-secondary:hover {
  background-color: var(--color-white);
  border-color: var(--color-indigo);
  color: var(--color-indigo);
  transform: translateY(-1px);
}

.btn-header {
  padding: 9px 18px;
  font-size: 0.88rem;
  background-color: var(--color-indigo);
  color: var(--color-white);
  border-radius: var(--radius-sm);
}
.btn-header:hover {
  background-color: var(--color-obsidian);
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */

.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: rgba(245, 242, 234, 0.94);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(23, 24, 29, 0.08);
  height: var(--header-height);
  display: flex;
  align-items: center;
  transition: background-color var(--transition-fast), border-color var(--transition-fast);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-link {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-logo {
  height: 44px;
  width: auto;
}

.main-nav {
  display: flex;
  align-items: center;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-link {
  font-size: 0.93rem;
  font-weight: 600;
  color: var(--color-graphite);
  padding: 6px 2px;
  position: relative;
  transition: color var(--transition-fast);
}

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

.nav-link:hover {
  color: var(--color-indigo);
}

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

.header-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

/* Hamburger Toggle Button */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: space-between;
  width: 32px;
  height: 24px;
  padding: 2px;
  cursor: pointer;
  z-index: 1010;
  background: transparent;
  border: none;
}

.nav-toggle__bar {
  display: block;
  width: 100%;
  height: 2px;
  background-color: var(--color-obsidian);
  border-radius: 2px;
  transition: transform var(--transition-base), opacity var(--transition-fast);
}

.nav-toggle.is-active .nav-toggle__bar:nth-child(1) {
  transform: translateY(9px) rotate(45deg);
}
.nav-toggle.is-active .nav-toggle__bar:nth-child(2) {
  opacity: 0;
}
.nav-toggle.is-active .nav-toggle__bar:nth-child(3) {
  transform: translateY(-9px) rotate(-45deg);
}

/* ==========================================================================
   Hero Section
   ========================================================================== */

.hero-section {
  position: relative;
  background-color: var(--color-paper);
  padding: 72px 0 80px;
  border-bottom: 1px solid rgba(23, 24, 29, 0.08);
  /* Technical Grid Pattern */
  background-image: 
    linear-gradient(to right, rgba(52, 56, 64, 0.04) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(52, 56, 64, 0.04) 1px, transparent 1px);
  background-size: 36px 36px;
  background-position: center top;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.95fr;
  gap: 56px;
  align-items: center;
}

.hero-content {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.hero-title {
  font-family: var(--font-sans);
  font-size: clamp(2.2rem, 3.8vw, 3.3rem);
  font-weight: 800;
  color: var(--color-obsidian);
  line-height: 1.16;
  letter-spacing: -0.03em;
  margin-bottom: 22px;
}

.hero-title-highlight {
  color: var(--color-indigo);
  background: linear-gradient(180deg, transparent 65%, var(--color-lime-tint) 65%);
  padding: 0 4px;
  border-radius: 2px;
}

.hero-description {
  font-size: 1.14rem;
  color: var(--color-graphite);
  line-height: 1.68;
  margin-bottom: 32px;
  max-width: 580px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
  margin-bottom: 28px;
}

.hero-note {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--color-slate);
  letter-spacing: 0.04em;
  padding: 4px 10px;
  background-color: rgba(23, 24, 29, 0.04);
  border-radius: var(--radius-xs);
  border-left: 2px solid var(--color-lime);
}

/* ==========================================================================
   Hero Visual Panel (Pure HTML/CSS Technical Framework)
   ========================================================================== */

.hero-panel {
  background-color: var(--color-white);
  border: 1px solid rgba(23, 24, 29, 0.12);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
  padding: 28px;
  position: relative;
  overflow: hidden;
}

.hero-panel::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--color-indigo) 0%, var(--color-amber) 60%, var(--color-lime) 100%);
}

.hero-panel__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--color-fog);
  margin-bottom: 22px;
}

.hero-panel__title-group {
  display: flex;
  align-items: center;
  gap: 12px;
}

.hero-panel__mark {
  width: 32px;
  height: 32px;
  border-radius: 8px;
}

.hero-panel__title {
  font-family: var(--font-sans);
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--color-obsidian);
}

.hero-panel__status {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--color-indigo);
  background-color: var(--color-indigo-subtle);
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--color-indigo-border);
}

.hero-panel__status-dot {
  width: 6px;
  height: 6px;
  background-color: var(--color-lime);
  border-radius: 50%;
  box-shadow: 0 0 0 2px rgba(182, 216, 74, 0.4);
}

.hero-stages {
  display: flex;
  flex-direction: column;
  gap: 14px;
  position: relative;
}

.hero-stages::before {
  content: '';
  position: absolute;
  left: 17px;
  top: 24px;
  bottom: 24px;
  width: 2px;
  background-color: var(--color-fog);
  z-index: 1;
}

.hero-stage-item {
  position: relative;
  display: flex;
  align-items: flex-start;
  gap: 16px;
  padding: 12px 14px;
  background-color: var(--color-fog-light);
  border: 1px solid rgba(23, 24, 29, 0.06);
  border-radius: var(--radius-sm);
  z-index: 2;
  transition: all var(--transition-fast);
}

.hero-stage-item:hover {
  background-color: var(--color-white);
  border-color: var(--color-indigo-border);
  box-shadow: var(--shadow-subtle);
  transform: translateX(3px);
}

.hero-stage-number {
  flex-shrink: 0;
  width: 26px;
  height: 26px;
  background-color: var(--color-obsidian);
  color: var(--color-lime);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 4px;
}

.hero-stage-item:nth-child(2) .hero-stage-number {
  background-color: var(--color-indigo);
  color: var(--color-white);
}

.hero-stage-item:nth-child(3) .hero-stage-number {
  background-color: var(--color-graphite);
  color: var(--color-amber);
}

.hero-stage-item:nth-child(4) .hero-stage-number {
  background-color: var(--color-obsidian);
  color: var(--color-lime);
}

.hero-stage-content {
  flex: 1;
}

.hero-stage-heading {
  font-size: 0.94rem;
  font-weight: 700;
  color: var(--color-obsidian);
  margin-bottom: 2px;
}

.hero-stage-desc {
  font-size: 0.84rem;
  color: var(--color-slate);
  line-height: 1.45;
}

.hero-panel__footer {
  margin-top: 18px;
  padding-top: 14px;
  border-top: 1px solid var(--color-fog);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--color-slate);
  letter-spacing: 0.06em;
}

/* ==========================================================================
   Statistics Section
   ========================================================================== */

.stats-section {
  background-color: var(--color-obsidian);
  color: var(--color-white);
  padding: 44px 0;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.stat-item {
  padding: 12px 18px;
  border-left: 1px solid rgba(255, 255, 255, 0.14);
}

.stat-item:first-child {
  border-left: none;
}

.stat-value {
  font-family: var(--font-mono);
  font-size: clamp(2rem, 3.2vw, 2.6rem);
  font-weight: 700;
  color: var(--color-lime);
  line-height: 1.1;
  margin-bottom: 6px;
}

.stat-label {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-slate-light);
  line-height: 1.35;
}

/* ==========================================================================
   Section: Connected Fields
   ========================================================================== */

.section-fields {
  padding: 96px 0;
  background-color: var(--color-white);
  border-bottom: 1px solid var(--color-fog);
}

.fields-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}

.field-card {
  background-color: var(--color-paper-light);
  border: 1px solid rgba(23, 24, 29, 0.09);
  border-radius: var(--radius-md);
  padding: 32px;
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
}

.field-card:hover {
  transform: translateY(-3px);
  border-color: var(--color-indigo);
  box-shadow: var(--shadow-card-hover);
  background-color: var(--color-white);
}

.field-card__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 18px;
}

.field-card__number {
  font-family: var(--font-mono);
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--color-indigo);
  background-color: var(--color-indigo-subtle);
  padding: 4px 10px;
  border-radius: var(--radius-xs);
  border: 1px solid var(--color-indigo-border);
}

.field-card__title {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--color-obsidian);
  margin-bottom: 12px;
  line-height: 1.3;
}

.field-card__desc {
  font-size: 0.96rem;
  color: var(--color-graphite);
  line-height: 1.62;
  margin-bottom: 24px;
  flex: 1;
}

.field-card__topics-title {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-slate);
  margin-bottom: 10px;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag {
  font-family: var(--font-mono);
  font-size: 0.76rem;
  font-weight: 500;
  background-color: var(--color-fog);
  color: var(--color-graphite);
  padding: 4px 10px;
  border-radius: var(--radius-xs);
  border: 1px solid rgba(23, 24, 29, 0.05);
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.field-card:hover .tag {
  background-color: var(--color-paper);
}

/* ==========================================================================
   Section: Structured Method
   ========================================================================== */

.section-method {
  padding: 96px 0;
  background-color: var(--color-paper);
  border-bottom: 1px solid rgba(23, 24, 29, 0.08);
}

.method-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 52px;
  align-items: flex-start;
}

.method-checklist-card {
  background-color: var(--color-white);
  border: 1px solid rgba(23, 24, 29, 0.1);
  border-radius: var(--radius-md);
  padding: 32px;
  box-shadow: var(--shadow-card);
}

.method-checklist-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-obsidian);
  margin-bottom: 20px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--color-fog);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.checklist-items {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.checklist-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  font-size: 0.94rem;
  color: var(--color-graphite);
  line-height: 1.45;
}

.checklist-icon {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
  margin-top: 1px;
  background-color: var(--color-indigo-subtle);
  color: var(--color-indigo);
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--color-indigo-border);
}

.method-steps {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.method-step-card {
  background-color: var(--color-white);
  border: 1px solid rgba(23, 24, 29, 0.08);
  border-radius: var(--radius-sm);
  padding: 22px 24px;
  display: flex;
  align-items: flex-start;
  gap: 20px;
  transition: transform var(--transition-fast), border-color var(--transition-fast);
}

.method-step-card:hover {
  transform: translateX(4px);
  border-color: var(--color-indigo);
  box-shadow: var(--shadow-subtle);
}

.method-step-num {
  font-family: var(--font-mono);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-indigo);
  line-height: 1;
  padding-top: 2px;
}

.method-step-body {
  flex: 1;
}

.method-step-heading {
  font-size: 1.08rem;
  font-weight: 700;
  color: var(--color-obsidian);
  margin-bottom: 4px;
}

.method-step-text {
  font-size: 0.91rem;
  color: var(--color-slate);
  line-height: 1.55;
}

/* ==========================================================================
   Section: Academic References (Researchers)
   ========================================================================== */

.section-researchers {
  padding: 96px 0;
  background-color: var(--color-white);
  border-bottom: 1px solid var(--color-fog);
}

.researchers-intro {
  background-color: var(--color-paper-light);
  border-left: 3px solid var(--color-indigo);
  padding: 16px 20px;
  border-radius: 0 var(--radius-xs) var(--radius-xs) 0;
  margin-bottom: 40px;
  max-width: 860px;
}

.researchers-intro p {
  font-size: 0.92rem;
  color: var(--color-slate);
  line-height: 1.6;
}

.researchers-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.researcher-card {
  background-color: var(--color-paper-light);
  border: 1px solid rgba(23, 24, 29, 0.09);
  border-radius: var(--radius-md);
  padding: 28px;
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
}

.researcher-card:hover {
  transform: translateY(-3px);
  border-color: var(--color-indigo);
  box-shadow: var(--shadow-card-hover);
  background-color: var(--color-white);
}

.researcher-card__top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
}

.researcher-avatar {
  width: 48px;
  height: 48px;
  background-color: var(--color-obsidian);
  color: var(--color-lime);
  font-family: var(--font-mono);
  font-size: 1.05rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  border: 1px solid rgba(255, 255, 255, 0.1);
  letter-spacing: 0.05em;
}

.researcher-country {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  font-weight: 600;
  color: var(--color-slate);
  background-color: var(--color-fog);
  padding: 3px 8px;
  border-radius: var(--radius-xs);
  letter-spacing: 0.04em;
}

.researcher-name {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-obsidian);
  margin-bottom: 4px;
}

.researcher-institution {
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--color-indigo);
  margin-bottom: 2px;
}

.researcher-dept {
  font-size: 0.83rem;
  color: var(--color-slate);
  margin-bottom: 6px;
  line-height: 1.35;
}

.researcher-role {
  font-size: 0.84rem;
  font-weight: 600;
  color: var(--color-graphite);
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--color-fog);
}

.researcher-summary {
  font-size: 0.88rem;
  color: var(--color-graphite);
  line-height: 1.58;
  margin-bottom: 22px;
  flex: 1;
}

.researcher-footer {
  margin-top: auto;
}

/* Identifier / Tags */
.researcher-identifier {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 0.76rem;
  color: var(--color-slate);
  background-color: var(--color-fog);
  padding: 4px 8px;
  border-radius: var(--radius-xs);
  margin-bottom: 16px;
}

/* Demo Platform Alias Box */
.alias-box {
  background-color: var(--color-fog-light);
  border: 1px solid var(--color-fog);
  border-radius: var(--radius-sm);
  padding: 12px 14px;
}

.alias-label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-slate);
  margin-bottom: 6px;
}

.alias-action-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}

.alias-address {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--color-obsidian);
  word-break: break-all;
}

.btn-copy {
  flex-shrink: 0;
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--color-indigo);
  background-color: var(--color-white);
  border: 1px solid var(--color-indigo-border);
  padding: 4px 8px;
  border-radius: var(--radius-xs);
  transition: all var(--transition-fast);
}

.btn-copy:hover {
  background-color: var(--color-indigo);
  color: var(--color-white);
}

.btn-copy.is-copied {
  background-color: var(--color-lime);
  color: var(--color-obsidian);
  border-color: var(--color-lime-dark);
}

/* ==========================================================================
   Section: Learning Library
   ========================================================================== */

.section-library {
  padding: 96px 0;
  background-color: var(--color-paper);
  border-bottom: 1px solid rgba(23, 24, 29, 0.08);
}

.library-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.library-card {
  background-color: var(--color-white);
  border: 1px solid rgba(23, 24, 29, 0.09);
  border-radius: var(--radius-md);
  padding: 30px;
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
}

.library-card:hover {
  transform: translateY(-3px);
  border-color: var(--color-indigo);
  box-shadow: var(--shadow-card-hover);
}

.library-card__category {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-indigo);
  background-color: var(--color-indigo-subtle);
  padding: 3px 10px;
  border-radius: var(--radius-pill);
  margin-bottom: 16px;
  align-self: flex-start;
}

.library-card__title {
  font-size: 1.18rem;
  font-weight: 700;
  color: var(--color-obsidian);
  margin-bottom: 12px;
  line-height: 1.35;
}

.library-card__desc {
  font-size: 0.91rem;
  color: var(--color-graphite);
  line-height: 1.6;
}

/* ==========================================================================
   Section: About & Principles
   ========================================================================== */

.section-about {
  padding: 96px 0;
  background-color: var(--color-white);
  border-bottom: 1px solid var(--color-fog);
}

.about-intro-text {
  font-size: 1.15rem;
  color: var(--color-graphite);
  line-height: 1.7;
  max-width: 880px;
  margin-bottom: 48px;
}

.principles-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  margin-bottom: 48px;
}

.principle-card {
  background-color: var(--color-paper-light);
  border: 1px solid rgba(23, 24, 29, 0.09);
  border-radius: var(--radius-md);
  padding: 28px;
}

.principle-num {
  font-family: var(--font-mono);
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--color-indigo);
  margin-bottom: 12px;
}

.principle-title {
  font-size: 1.12rem;
  font-weight: 700;
  color: var(--color-obsidian);
  margin-bottom: 8px;
}

.principle-desc {
  font-size: 0.91rem;
  color: var(--color-graphite);
  line-height: 1.6;
}

/* Reference Notice / Disclaimer Box */
.reference-notice-box {
  background-color: var(--color-fog-light);
  border: 1px solid rgba(23, 24, 29, 0.1);
  border-left: 4px solid var(--color-amber);
  border-radius: var(--radius-sm);
  padding: 22px 26px;
  display: flex;
  align-items: flex-start;
  gap: 18px;
}

.reference-notice-icon {
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  color: var(--color-amber);
  margin-top: 2px;
}

.reference-notice-title {
  font-family: var(--font-mono);
  font-size: 0.84rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-obsidian);
  margin-bottom: 4px;
}

.reference-notice-text {
  font-size: 0.89rem;
  color: var(--color-graphite);
  line-height: 1.55;
}

/* ==========================================================================
   Footer
   ========================================================================== */

.site-footer {
  background-color: var(--color-obsidian);
  color: var(--color-white);
  padding: 64px 0 36px;
}

.footer-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 28px;
  padding-bottom: 40px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  margin-bottom: 32px;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 16px;
}

.footer-mark {
  width: 42px;
  height: 42px;
}

.footer-brand-title {
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--color-white);
}

.footer-brand-desc {
  font-size: 0.82rem;
  color: var(--color-slate-light);
}

.footer-nav {
  display: flex;
  align-items: center;
  gap: 28px;
  flex-wrap: wrap;
}

.footer-nav-link {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-slate-light);
  transition: color var(--transition-fast);
}

.footer-nav-link:hover {
  color: var(--color-lime);
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 0.84rem;
  color: var(--color-slate);
}

.back-to-top {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--color-slate-light);
  font-family: var(--font-mono);
  font-size: 0.82rem;
  transition: color var(--transition-fast);
}

.back-to-top:hover {
  color: var(--color-lime);
}

/* Toast Notification (Copy feedback) */
.copy-toast {
  position: fixed;
  bottom: 24px;
  right: 24px;
  background-color: var(--color-obsidian);
  color: var(--color-lime);
  border: 1px solid var(--color-lime);
  padding: 10px 18px;
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.84rem;
  font-weight: 600;
  box-shadow: var(--shadow-elevation);
  z-index: 9999;
  opacity: 0;
  transform: translateY(12px);
  pointer-events: none;
  transition: opacity var(--transition-base), transform var(--transition-base);
}

.copy-toast.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ==========================================================================
   Progressive Scroll Animations
   Visible by default; animated only when JS is enabled
   ========================================================================== */

.reveal {
  opacity: 1;
  transform: none;
}

.js-enabled .reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 550ms cubic-bezier(0.16, 1, 0.3, 1), transform 550ms cubic-bezier(0.16, 1, 0.3, 1);
}

.js-enabled .reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */

@media (max-width: 1024px) {
  .researchers-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .library-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 860px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }
  .method-layout {
    grid-template-columns: 1fr;
    gap: 36px;
  }
  .principles-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
  }
  .stat-item:nth-child(3) {
    border-left: none;
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 68px;
  }

  .nav-toggle {
    display: flex;
  }

  .main-nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background-color: var(--color-paper-light);
    border-bottom: 1px solid rgba(23, 24, 29, 0.12);
    padding: 24px var(--container-padding);
    transform: translateY(-110%);
    opacity: 0;
    pointer-events: none;
    transition: transform var(--transition-base), opacity var(--transition-base);
    box-shadow: var(--shadow-elevation);
    flex-direction: column;
    align-items: flex-start;
  }

  .main-nav.is-open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .nav-list {
    flex-direction: column;
    align-items: flex-start;
    gap: 18px;
    width: 100%;
  }

  .nav-link {
    font-size: 1.05rem;
    display: block;
    width: 100%;
    padding: 6px 0;
  }

  .header-cta-desktop {
    display: none;
  }

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

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

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

  .section-fields,
  .section-method,
  .section-researchers,
  .section-library,
  .section-about {
    padding: 64px 0;
  }
}

@media (max-width: 480px) {
  .stats-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }
  .stat-item {
    border-left: none;
    padding-left: 0;
  }
  .hero-actions {
    flex-direction: column;
    width: 100%;
  }
  .hero-actions .btn {
    width: 100%;
  }
  .footer-top {
    flex-direction: column;
    align-items: flex-start;
  }
  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
  }
}

/* Reduced Motion Preference */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  .js-enabled .reveal {
    opacity: 1 !important;
    transform: none !important;
  }
}