/* =====================================================
   HUMAN OPERATING SYSTEM — MICROSITE
   Premium B2B Design System
   ===================================================== */

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

:root {
  /* Colors */
  --bg-primary: #F6F7FB;
  --bg-card: rgba(255, 255, 255, 0.92);
  --bg-card-hover: rgba(255, 255, 255, 1);
  --bg-subtle: rgba(11, 15, 26, 0.03);
  --bg-subtle-hover: rgba(11, 15, 26, 0.06);
  
  --text-primary: #0B0F1A;
  --text-secondary: #4B5563;
  --text-muted: #6B7280;
  --text-light: #9CA3AF;
  
  --border-light: rgba(11, 15, 26, 0.10);
  --border-medium: rgba(11, 15, 26, 0.15);
  
  /* Dimension Colors */
  --color-motivation: #E8B931;
  --color-processing: #4ECDC4;
  --color-stress: #E85D4E;
  --color-communication: #7B68EE;
  --color-signals: #FF8C42;
  --color-dynamics: #57A773;
  
  /* Accent */
  --accent-primary: #0B0F1A;
  --accent-secondary: #374151;
  
  /* Spacing */
  --space-xs: 8px;
  --space-sm: 16px;
  --space-md: 24px;
  --space-lg: 40px;
  --space-xl: 64px;
  --space-2xl: 96px;
  
  /* Typography */
  --font-family: 'DM Sans', system-ui, -apple-system, sans-serif;
  
  /* Container */
  --container-max: 1200px;
  --container-narrow: 800px;
  
  /* Transitions */
  --transition-fast: 0.2s ease;
  --transition-medium: 0.3s ease;
  
  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
}

html {
  scroll-behavior: smooth;
}

body {
  background: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-family);
  font-size: 16px;
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
}

/* === GRID BACKGROUND === */
.bg-grid {
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(11, 15, 26, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(11, 15, 26, 0.04) 1px, transparent 1px);
  background-size: 60px 60px;
  z-index: 0;
}

/* === TYPOGRAPHY === */
h1, h2, h3, h4, h5, h6 {
  font-weight: 300;
  line-height: 1.2;
  letter-spacing: -0.5px;
  color: var(--text-primary);
}

h1 { font-size: clamp(36px, 6vw, 56px); }
h2 { font-size: clamp(28px, 4vw, 42px); }
h3 { font-size: clamp(22px, 3vw, 28px); }
h4 { font-size: 20px; }

h1 strong, h2 strong, h3 strong, h4 strong {
  font-weight: 700;
}

p {
  color: var(--text-secondary);
  line-height: 1.75;
}

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

/* === LAYOUT === */
.page-wrapper {
  position: relative;
  z-index: 1;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-md);
}

.container--narrow {
  max-width: var(--container-narrow);
}

/* === NAVIGATION === */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(246, 247, 251, 0.92);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-light);
  transition: all var(--transition-medium);
}

.nav--scrolled {
  box-shadow: 0 4px 20px rgba(11, 15, 26, 0.06);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-md);
}

.nav__logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 700;
  font-size: 15px;
  letter-spacing: 0.5px;
  color: var(--text-primary);
}

.nav__logo-icon {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--text-primary);
  border-radius: var(--radius-sm);
}

.nav__logo-icon svg {
  width: 20px;
  height: 20px;
  stroke: var(--bg-primary);
}

.nav__links {
  display: flex;
  align-items: center;
  gap: 8px;
  list-style: none;
}

.nav__link {
  padding: 8px 14px;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.nav__link:hover {
  color: var(--text-primary);
  background: var(--bg-subtle);
}

.nav__link--active {
  color: var(--text-primary);
  background: var(--bg-subtle);
}

.nav__cta {
  margin-left: 8px;
}

/* Mobile Menu Toggle */
.nav__toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  padding: 10px;
  background: transparent;
  border: none;
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: background var(--transition-fast);
}

.nav__toggle:hover {
  background: var(--bg-subtle);
}

.nav__toggle span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: all var(--transition-fast);
}

.nav__toggle[aria-expanded="true"] span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.nav__toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}

.nav__toggle[aria-expanded="true"] span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* Mobile Menu */
.nav__mobile {
  display: none;
  position: fixed;
  left: 0;
  right: 0;
  top: 72px;
  /* Use dynamic viewport units where available (iOS Safari address bar) */
  height: calc(100dvh - 72px);
  height: calc(100vh - 72px);
  background: var(--bg-primary);
  padding: var(--space-md);
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  overscroll-behavior: contain;
  z-index: 1500;
}

.nav__mobile.is-open {
  display: block;
  animation: fadeSlideIn 0.3s ease;
}

.nav__mobile-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.nav__mobile-link {
  display: block;
  padding: 16px;
  font-size: 16px;
  font-weight: 500;
  color: var(--text-secondary);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.nav__mobile-link:hover,
.nav__mobile-link--active {
  color: var(--text-primary);
  background: var(--bg-subtle);
}

.nav__mobile-cta {
  margin-top: var(--space-md);
}

/* === MAIN CONTENT === */
main {
  flex: 1;
  padding-top: 72px;
}

/* === SECTIONS === */
.section {
  padding: var(--space-xl) 0;
}

.section--hero {
  padding: var(--space-2xl) 0 var(--space-xl);
}

.section--alt {
  background: rgba(11, 15, 26, 0.02);
}

.section__header {
  text-align: center;
  margin-bottom: var(--space-lg);
}

.section__header--left {
  text-align: left;
}

.section__kicker {
  display: inline-block;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 3px;
  color: var(--text-muted);
  margin-bottom: var(--space-sm);
  text-transform: uppercase;
}

.section__title {
  margin-bottom: var(--space-sm);
}

.section__subtitle {
  font-size: 18px;
  color: var(--text-secondary);
  max-width: 640px;
  margin: 0 auto;
}

.section__header--left .section__subtitle {
  margin: 0;
}

/* === BUTTONS === */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 28px;
  font-family: var(--font-family);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.5px;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: all var(--transition-medium);
  white-space: nowrap;
}

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

.btn--primary:hover {
  background: var(--accent-secondary);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(11, 15, 26, 0.15);
}

.btn--secondary {
  background: transparent;
  color: var(--text-primary);
  border: 1.5px solid var(--border-medium);
}

.btn--secondary:hover {
  background: var(--bg-subtle);
  border-color: var(--text-primary);
}

.btn--ghost {
  background: transparent;
  color: var(--text-secondary);
  padding: 10px 16px;
}

.btn--ghost:hover {
  color: var(--text-primary);
  background: var(--bg-subtle);
}

.btn--small {
  padding: 10px 18px;
  font-size: 13px;
}

.btn svg {
  width: 18px;
  height: 18px;
}

.btn-group {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: var(--space-md);
}

/* === CARDS === */
.cards {
  display: grid;
  gap: var(--space-md);
}

.cards--3 {
  grid-template-columns: repeat(3, 1fr);
}

.cards--4 {
  grid-template-columns: repeat(4, 1fr);
}

.cards--2 {
  grid-template-columns: repeat(2, 1fr);
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-md);
  transition: all var(--transition-medium);
}

.card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-medium);
  transform: translateY(-4px);
  box-shadow: 0 12px 32px rgba(11, 15, 26, 0.08);
}

.card__icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  margin-bottom: var(--space-sm);
  background: var(--bg-subtle);
}

.card__icon svg {
  width: 24px;
  height: 24px;
  stroke: var(--text-primary);
}

.card__number {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: var(--text-primary);
  color: var(--bg-primary);
  font-weight: 700;
  font-size: 16px;
  margin-bottom: var(--space-sm);
}

.card__title {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: var(--space-xs);
  color: var(--text-primary);
}

.card__text {
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.6;
}

.card__list {
  list-style: none;
  margin-top: var(--space-sm);
}

.card__list li {
  position: relative;
  padding-left: 16px;
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 6px;
}

.card__list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 8px;
  width: 5px;
  height: 5px;
  background: var(--text-muted);
  border-radius: 50%;
}

/* Card Accent Colors */
.card--motivation .card__icon { background: rgba(232, 185, 49, 0.15); }
.card--motivation .card__icon svg { stroke: var(--color-motivation); }

.card--processing .card__icon { background: rgba(78, 205, 196, 0.15); }
.card--processing .card__icon svg { stroke: var(--color-processing); }

.card--stress .card__icon { background: rgba(232, 93, 78, 0.15); }
.card--stress .card__icon svg { stroke: var(--color-stress); }

.card--communication .card__icon { background: rgba(123, 104, 238, 0.15); }
.card--communication .card__icon svg { stroke: var(--color-communication); }

.card--signals .card__icon { background: rgba(255, 140, 66, 0.15); }
.card--signals .card__icon svg { stroke: var(--color-signals); }

.card--dynamics .card__icon { background: rgba(87, 167, 115, 0.15); }
.card--dynamics .card__icon svg { stroke: var(--color-dynamics); }

/* === BULLET LIST === */
.bullet-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.bullet-list li {
  position: relative;
  padding-left: 24px;
  font-size: 16px;
  color: var(--text-secondary);
}

.bullet-list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 10px;
  width: 6px;
  height: 6px;
  background: var(--text-primary);
  border-radius: 50%;
}

.bullet-list--muted li::before {
  background: var(--text-muted);
}

/* === DIVIDER === */
.divider {
  height: 1px;
  background: var(--border-light);
  margin: var(--space-lg) 0;
}

/* === PANELS / BOXES === */
.panel {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
}

.panel--subtle {
  background: var(--bg-subtle);
  border: none;
}

.panel__title {
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 2px;
  color: var(--text-muted);
  margin-bottom: var(--space-sm);
  text-transform: uppercase;
}

/* === HERO === */
.hero {
  text-align: center;
  padding: var(--space-2xl) 0 var(--space-xl);
}

.hero__title {
  margin-bottom: var(--space-sm);
}

.hero__subtitle {
  font-size: 20px;
  color: var(--text-secondary);
  max-width: 680px;
  margin: 0 auto var(--space-md);
  line-height: 1.6;
}

.hero__microcopy {
  font-size: 15px;
  color: var(--text-muted);
  max-width: 560px;
  margin: 0 auto var(--space-lg);
}

/* === STEPS === */
.steps {
  counter-reset: step;
}

.step {
  position: relative;
  padding-left: 80px;
  padding-bottom: var(--space-xl);
}

.step:last-child {
  padding-bottom: 0;
}

.step::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  left: 0;
  top: 0;
  width: 56px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--text-primary);
  color: var(--bg-primary);
  font-size: 20px;
  font-weight: 700;
  border-radius: 50%;
}

.step:not(:last-child)::after {
  content: '';
  position: absolute;
  left: 27px;
  top: 60px;
  width: 2px;
  height: calc(100% - 68px);
  background: var(--border-light);
}

.step__content {
  padding-top: 4px;
}

.step__title {
  font-size: 22px;
  font-weight: 600;
  margin-bottom: var(--space-xs);
}

.step__subtitle {
  font-size: 15px;
  color: var(--text-muted);
  margin-bottom: var(--space-sm);
}

.step__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-md);
  margin-top: var(--space-md);
}

.step__box {
  background: var(--bg-subtle);
  border-radius: var(--radius-md);
  padding: var(--space-sm);
}

.step__box-title {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 2px;
  color: var(--text-muted);
  margin-bottom: var(--space-xs);
  text-transform: uppercase;
}

.step__duration {
  display: inline-block;
  padding: 6px 12px;
  background: var(--bg-subtle);
  border-radius: var(--radius-sm);
  font-size: 13px;
  color: var(--text-muted);
  margin-top: var(--space-sm);
}

/* === COMPARISON TABLE === */
.comparison {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md);
}

.comparison__col {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-md);
}

.comparison__col--before {
  border-color: rgba(232, 93, 78, 0.3);
}

.comparison__col--after {
  border-color: rgba(87, 167, 115, 0.3);
}

.comparison__label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 2px;
  margin-bottom: var(--space-sm);
  text-transform: uppercase;
}

.comparison__col--before .comparison__label {
  color: var(--color-stress);
}

.comparison__col--after .comparison__label {
  color: var(--color-dynamics);
}

/* === CASE CARDS === */
.case {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  margin-bottom: var(--space-md);
}

.case__label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 2px;
  color: var(--text-muted);
  margin-bottom: var(--space-sm);
  text-transform: uppercase;
}

.case__title {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: var(--space-md);
}

.case__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-md);
}

.case__section-title {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 1px;
  color: var(--text-muted);
  margin-bottom: var(--space-xs);
  text-transform: uppercase;
}

.case__section-title--problem { color: var(--color-stress); }
.case__section-title--intervention { color: var(--color-processing); }
.case__section-title--result { color: var(--color-dynamics); }

/* === FORM === */
.form {
  max-width: 560px;
  margin: 0 auto;
}

.form__group {
  margin-bottom: var(--space-md);
}

.form__label {
  display: block;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-primary);
  margin-bottom: var(--space-xs);
}

.form__input,
.form__textarea {
  width: 100%;
  padding: 14px 18px;
  font-family: var(--font-family);
  font-size: 15px;
  color: var(--text-primary);
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.form__input:focus,
.form__textarea:focus {
  outline: none;
  border-color: var(--text-primary);
  box-shadow: 0 0 0 3px rgba(11, 15, 26, 0.08);
}

.form__textarea {
  min-height: 140px;
  resize: vertical;
}

.form__checkbox {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  font-size: 14px;
  color: var(--text-secondary);
}

.form__checkbox input {
  width: 18px;
  height: 18px;
  margin-top: 2px;
  accent-color: var(--text-primary);
}

.form__submit {
  width: 100%;
  margin-top: var(--space-md);
}

.form__note {
  font-size: 13px;
  color: var(--text-muted);
  margin-top: var(--space-md);
  text-align: center;
}

/* === CTA SECTION === */
.cta-section {
  text-align: center;
  padding: var(--space-xl) 0;
}

.cta-section__title {
  font-size: 28px;
  margin-bottom: var(--space-sm);
}

.cta-section__text {
  font-size: 16px;
  color: var(--text-secondary);
  margin-bottom: var(--space-md);
}

/* === FOOTER === */
.footer {
  padding: var(--space-lg) 0;
  border-top: 1px solid var(--border-light);
  margin-top: auto;
}

.footer__inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
  text-align: center;
}

.footer__brand {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 3px;
  color: var(--text-muted);
}

.footer__links {
  display: flex;
  gap: var(--space-md);
  list-style: none;
}

.footer__link {
  font-size: 13px;
  color: var(--text-muted);
}

.footer__link:hover {
  color: var(--text-primary);
}

/* === FRAMEWORK PAGE - RADAR COMPONENT === */
.framework-diagram {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 48px;
  flex-wrap: wrap;
  max-width: 1200px;
  margin: 0 auto;
}

.diagram-wrap {
  position: relative;
  width: 620px;
  height: 620px;
  flex-shrink: 0;
}

.diagram-wrap svg {
  width: 100%;
  height: 100%;
  overflow: visible;
}

.tooltip {
  position: absolute;
  pointer-events: none;
  padding: 8px 16px;
  border-radius: 10px;
  background: rgba(11, 15, 26, 0.08);
  border: 1px solid rgba(11, 15, 26, 0.12);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  font-size: 12px;
  color: var(--text-primary);
  letter-spacing: 0.3px;
  white-space: nowrap;
  opacity: 0;
  transition: opacity 0.2s ease;
  transform: translate(-50%, -100%);
  z-index: 10;
}

.tooltip.visible {
  opacity: 1;
}

.tooltip .tt-label {
  font-weight: 600;
  margin-bottom: 2px;
}

.tooltip .tt-cta {
  font-size: 11px;
  color: var(--text-secondary);
}

.hint {
  position: absolute;
  bottom: 12px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  border-radius: 24px;
  background: rgba(11, 15, 26, 0.04);
  border: 1px solid rgba(11, 15, 26, 0.10);
  animation: hintPulse 2.5s ease-in-out infinite;
  white-space: nowrap;
}

.hint span:first-child {
  font-size: 16px;
}

.hint span:last-child {
  font-size: 13px;
  color: var(--text-secondary);
  letter-spacing: 0.3px;
}

.hint.hidden {
  display: none;
}

.radar-panel {
  width: 400px;
  min-height: 460px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.panel-content {
  animation: fadeSlideIn 0.35s ease;
}

.panel-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 28px;
}

.panel-icon {
  width: 56px;
  height: 56px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 26px;
}

.panel-label {
  font-size: 13px;
  letter-spacing: 2px;
  font-weight: 600;
  margin-bottom: 3px;
}

.panel-tagline {
  font-size: 15px;
  color: var(--text-secondary);
}

.panel-desc {
  font-size: 16px;
  line-height: 1.75;
  color: var(--text-primary);
  margin-bottom: 32px;
}

.signals {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 32px;
}

.signal-item {
  display: flex;
  align-items: center;
  gap: 12px;
}

.signal-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  opacity: 0.7;
  flex-shrink: 0;
}

.signal-text {
  font-size: 15px;
  color: var(--text-secondary);
}

.action-box {
  padding: 20px 22px;
  border-radius: 12px;
  background: rgba(11, 15, 26, 0.03);
  border: 1px solid rgba(11, 15, 26, 0.10);
}

.action-text {
  font-size: 16px;
  color: var(--text-primary);
  font-weight: 500;
  line-height: 1.5;
}

.idle-panel .idle-title-sm {
  font-size: 11px;
  letter-spacing: 2.5px;
  color: var(--text-secondary);
  font-weight: 600;
  margin-bottom: 18px;
}

.idle-panel h3 {
  font-size: 26px;
  font-weight: 300;
  color: var(--text-primary);
  margin-bottom: 18px;
  line-height: 1.4;
}

.idle-panel h3 strong {
  font-weight: 700;
}

.idle-panel p {
  font-size: 16px;
  line-height: 1.75;
  color: var(--text-secondary);
  margin-bottom: 32px;
}

.idle-panel .arrow-hint {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text-muted);
  font-size: 14px;
}

.bottom-bar {
  display: flex;
  gap: 6px;
  margin-top: 44px;
  flex-wrap: wrap;
  justify-content: center;
}

.dim-btn {
  padding: 12px 20px;
  border-radius: 10px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 1.5px;
  cursor: pointer;
  transition: all 0.25s ease;
  font-family: inherit;
  background: rgba(11, 15, 26, 0.02);
  color: var(--text-secondary);
  border: 1px solid rgba(11, 15, 26, 0.10);
}

.dim-btn:hover {
  background: var(--bg-subtle);
  border-color: var(--border-medium);
}

.node-circle,
.node-icon {
  transition: all 0.3s ease;
}

/* === UTILITY CLASSES === */
.text-center { text-align: center; }
.text-left { text-align: left; }
.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }

/* === ANIMATIONS === */
@keyframes fadeSlideIn {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

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

@keyframes introDemo {
  0%   { transform: scale(1); }
  30%  { transform: scale(1.18); }
  60%  { transform: scale(1); }
  80%  { transform: scale(1.1); }
  100% { transform: scale(1); }
}

/* === RESPONSIVE === */
@media (max-width: 1060px) {
  .framework-diagram {
    flex-direction: column;
    gap: 32px;
  }
  
  .cards--3,
  .cards--4 {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .case__grid {
    grid-template-columns: 1fr;
    gap: var(--space-sm);
  }
}

@media (max-width: 768px) {
  :root {
    --space-xl: 48px;
    --space-2xl: 64px;
  }
  
  .nav__links {
    display: none;
  }
  
  .nav__toggle {
    display: flex;
  }
  
  .cards--2,
  .cards--3,
  .cards--4 {
    grid-template-columns: 1fr;
  }
  
  .comparison {
    grid-template-columns: 1fr;
  }
  
  .step {
    padding-left: 64px;
  }
  
  .step::before {
    width: 44px;
    height: 44px;
    font-size: 16px;
  }
  
  .step:not(:last-child)::after {
    left: 21px;
    top: 48px;
    height: calc(100% - 56px);
  }
  
  .step__grid {
    grid-template-columns: 1fr;
  }
  
  .hero__subtitle {
    font-size: 18px;
  }
  
  .section__subtitle {
    font-size: 16px;
  }
}

@media (max-width: 680px) {
  .diagram-wrap {
    width: 100%;
    height: auto;
    aspect-ratio: 1;
    max-width: 500px;
  }
  
  .hint {
    padding: 8px 14px;
  }
  
  .hint span:last-child {
    font-size: 12px;
  }
  
  .radar-panel {
    width: 100%;
    min-height: auto;
    padding: 0 6px;
  }
  
  .panel-icon {
    width: 48px;
    height: 48px;
    font-size: 22px;
    border-radius: 12px;
  }
  
  .panel-label {
    font-size: 12px;
  }
  
  .panel-tagline {
    font-size: 14px;
  }
  
  .panel-desc {
    font-size: 15px;
  }
  
  .signal-text {
    font-size: 14px;
  }
  
  .action-text {
    font-size: 15px;
  }
  
  .idle-panel h3 {
    font-size: 22px;
  }
  
  .idle-panel p {
    font-size: 15px;
  }
  
  .bottom-bar {
    gap: 4px;
  }
  
  .dim-btn {
    padding: 10px 14px;
    font-size: 11px;
  }
  
  .tooltip {
    display: none !important;
  }
  
  .btn-group {
    flex-direction: column;
  }
  
  .btn-group .btn {
    width: 100%;
  }
}

/* === FOCUS STATES (Accessibility) === */
.btn:focus-visible,
.nav__link:focus-visible,
.nav__toggle:focus-visible,
.form__input:focus-visible,
.form__textarea:focus-visible,
.dim-btn:focus-visible {
  outline: 2px solid var(--text-primary);
  outline-offset: 2px;
}

/* === SKIP LINK (Accessibility) === */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--text-primary);
  color: var(--bg-primary);
  padding: 8px 16px;
  z-index: 10000;
  transition: top 0.3s;
}

.skip-link:focus {
  top: 0;
}

/* === PRINT STYLES === */
@media print {
  .nav,
  .footer,
  .btn,
  .bg-grid {
    display: none !important;
  }
  
  main {
    padding-top: 0;
  }
  
  .section {
    padding: 20px 0;
    page-break-inside: avoid;
  }
}