/* =====================================================
   CHETAN PATADIYA PORTFOLIO — GLOBAL STYLESHEET
   Mobile-first, buildless, vanilla CSS
   ===================================================== */

/* --- DESIGN TOKENS --- */

:root {
  /* COLOR PALETTE */
  --color-navy: #16324F;
  --color-navy-light: #1F3A5F;
  --color-navy-dark: #0F2436;
  
  --color-teal: #147D7E;
  --color-teal-light: #1A9FA0;
  --color-teal-dark: #0F5B5C;
  
  --color-amber: #C98A28;
  --color-amber-light: #D9A04A;
  
  --color-neutral-0: #FFFFFF;
  --color-neutral-50: #F9FAFB;
  --color-neutral-100: #F3F4F6;
  --color-neutral-150: #EEEFF2;
  --color-neutral-200: #E5E7EB;
  --color-neutral-300: #D1D5DB;
  --color-neutral-400: #9CA3AF;
  --color-neutral-500: #6B7280;
  --color-neutral-600: #4B5563;
  --color-neutral-700: #374151;
  --color-neutral-800: #1F2937;
  --color-neutral-900: #111827;
  
  /* SEMANTIC COLORS */
  --color-bg: #F9FAFB;
  --color-surface: #FFFFFF;
  --color-text-primary: #111827;
  --color-text-secondary: #4B5563;
  --color-text-muted: #6B7280;
  --color-border: #E5E7EB;
  
  --color-brand-primary: var(--color-navy);
  --color-brand-accent: var(--color-teal);
  --color-brand-emphasis: var(--color-amber);
  
  /* SPACING SYSTEM */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-2xl: 48px;
  --space-3xl: 64px;
  
  /* TYPOGRAPHY */
  --font-family-sans: "Inter", "IBM Plex Sans", "Source Sans Pro", -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", sans-serif;
  --font-family-serif: "Georgia", "Garamond", serif;
  
  --font-size-xs: clamp(0.75rem, 2vw, 0.875rem);
  --font-size-sm: clamp(0.875rem, 2.5vw, 0.95rem);
  --font-size-base: clamp(1rem, 3vw, 1.0625rem);
  --font-size-lg: clamp(1.125rem, 3.5vw, 1.25rem);
  --font-size-xl: clamp(1.25rem, 4vw, 1.5rem);
  --font-size-2xl: clamp(1.5rem, 5vw, 1.875rem);
  --font-size-3xl: clamp(1.875rem, 6vw, 2.25rem);
  --font-size-4xl: clamp(2.25rem, 7vw, 3rem);
  
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;
  
  --font-weight-regular: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  
  /* BORDER RADIUS */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  
  /* SHADOWS */
  --shadow-xs: 0 1px 2px rgba(15, 23, 42, 0.05);
  --shadow-sm: 0 2px 8px rgba(15, 23, 42, 0.06);
  --shadow-md: 0 10px 30px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 20px 50px rgba(15, 23, 42, 0.12);
  
  /* LAYOUT */
  --content-width: 1200px;
  --content-width-narrow: 900px;
  
  /* TRANSITIONS */
  --transition-fast: 150ms ease;
  --transition-normal: 200ms ease;
  --transition-slow: 300ms ease;
}

/* --- GLOBAL RESETS --- */

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-family-sans);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-text-primary);
  background: var(--color-bg);
}

/* --- TYPOGRAPHY --- */

h1, h2, h3, h4, h5, h6 {
  margin: 0;
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
}

h1 {
  font-size: var(--font-size-4xl);
  color: var(--color-navy-dark);
}

h2 {
  font-size: var(--font-size-3xl);
  color: var(--color-text-primary);
}

h3 {
  font-size: var(--font-size-2xl);
  color: var(--color-text-primary);
}

h4 {
  font-size: var(--font-size-xl);
  color: var(--color-text-primary);
}

h5 {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
}

h6 {
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

p {
  margin: 0;
}

p + p {
  margin-top: var(--space-md);
}

small {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

strong {
  font-weight: var(--font-weight-bold);
}

em {
  font-style: italic;
}

/* --- LINKS --- */

a {
  color: var(--color-brand-accent);
  text-decoration: none;
  transition: color var(--transition-normal);
}

a:hover {
  color: var(--color-teal-dark);
}

a:focus-visible {
  outline: 2px solid var(--color-brand-accent);
  outline-offset: 2px;
}

/* --- LISTS --- */

ul, ol {
  margin: 0;
  padding-left: var(--space-lg);
}

ul ul, ul ol, ol ul, ol ol {
  margin-top: var(--space-sm);
}

li {
  margin-bottom: var(--space-sm);
  line-height: var(--line-height-relaxed);
}

li:last-child {
  margin-bottom: 0;
}

/* --- FORMS --- */

label {
  display: block;
  font-weight: var(--font-weight-medium);
  margin-bottom: var(--space-sm);
  color: var(--color-text-primary);
}

input, textarea, select {
  font-family: inherit;
  font-size: inherit;
  color: inherit;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-sm) var(--space-md);
  width: 100%;
  max-width: 100%;
}

input:focus, textarea:focus, select:focus {
  outline: none;
  border-color: var(--color-brand-accent);
  box-shadow: 0 0 0 3px rgba(20, 125, 126, 0.1);
}

/* --- LAYOUT UTILITIES --- */

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

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

/* Spacing utilities */
.mt-0 { margin-top: 0; }
.mt-xs { margin-top: var(--space-xs); }
.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mt-xl { margin-top: var(--space-xl); }
.mt-2xl { margin-top: var(--space-2xl); }
.mt-3xl { margin-top: 52px; }

.mb-0 { margin-bottom: 0; }
.mb-xs { margin-bottom: var(--space-xs); }
.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }
.mb-xl { margin-bottom: var(--space-xl); }
.mb-2xl { margin-bottom: var(--space-2xl); }
.mb-3xl { margin-bottom: 52px; }

.py-md { padding-top: var(--space-md); padding-bottom: var(--space-md); }
.py-lg { padding-top: var(--space-lg); padding-bottom: var(--space-lg); }
.py-xl { padding-top: var(--space-xl); padding-bottom: var(--space-xl); }
.py-2xl { padding-top: var(--space-2xl); padding-bottom: var(--space-2xl); }

/* --- COMPONENT: BUTTONS --- */

.button, button {
  display: inline-block;
  padding: var(--space-sm) var(--space-lg);
  border: none;
  border-radius: var(--radius-md);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  text-decoration: none;
  cursor: pointer;
  transition: all var(--transition-normal);
  text-align: center;
  user-select: none;
  -webkit-user-select: none;
}

button:focus-visible, .button:focus-visible {
  outline: 2px solid var(--color-brand-accent);
  outline-offset: 2px;
}

/* Primary button */
.button-primary, button.primary {
  background: var(--color-brand-primary);
  color: white;
}

.button-primary:hover, button.primary:hover {
  background: var(--color-navy-dark);
  transform: translateY(-1px);
}

.button-primary:active, button.primary:active {
  transform: translateY(0);
}

/* Secondary button */
.button-secondary, button.secondary {
  background: var(--color-neutral-100);
  color: var(--color-text-primary);
  border: 1px solid var(--color-border);
}

.button-secondary:hover, button.secondary:hover {
  background: var(--color-neutral-150);
  border-color: var(--color-neutral-300);
}

/* Accent button */
.button-accent {
  background: var(--color-brand-accent);
  color: white;
}

.button-accent:hover {
  background: var(--color-teal-dark);
  transform: translateY(-1px);
}

/* Ghost button */
.button-ghost {
  background: transparent;
  color: var(--color-brand-accent);
  border: 2px solid var(--color-brand-accent);
  padding: calc(var(--space-sm) - 2px) calc(var(--space-lg) - 2px);
}

.button-ghost:hover {
  background: rgba(20, 125, 126, 0.05);
  border-color: var(--color-teal-dark);
}

/* Button sizes */
.button-small {
  padding: 6px 12px;
  font-size: var(--font-size-sm);
}

.button-large {
  padding: var(--space-md) var(--space-xl);
  font-size: var(--font-size-lg);
}

/* --- COMPONENT: CARDS --- */

.card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border);
  transition: all var(--transition-normal);
}

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

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

.card-title {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-sm);
}

.card-subtitle {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  font-weight: var(--font-weight-medium);
}

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

.card-body p {
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--space-sm);
}

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

.card-footer {
  margin-top: var(--space-lg);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border);
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
  align-items: center;
}

/* --- COMPONENT: BADGES & STATUS LABELS --- */

.badge {
  display: inline-block;
  padding: 4px 8px;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  line-height: 1;
}

.badge-primary {
  background: rgba(22, 50, 79, 0.1);
  color: var(--color-navy);
}

.badge-teal {
  background: rgba(20, 125, 126, 0.1);
  color: var(--color-teal);
}

.badge-amber {
  background: rgba(201, 138, 40, 0.1);
  color: var(--color-amber);
}

.badge-neutral {
  background: var(--color-neutral-150);
  color: var(--color-text-secondary);
}

/* Status badges */
.status-label {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.status-live .status-indicator {
  width: 6px;
  height: 6px;
  background: #10b981;
  border-radius: 50%;
  display: inline-block;
}

.status-poc .status-indicator {
  width: 6px;
  height: 6px;
  background: var(--color-amber);
  border-radius: 50%;
  display: inline-block;
}

.status-dev .status-indicator {
  width: 6px;
  height: 6px;
  background: var(--color-teal);
  border-radius: 50%;
  display: inline-block;
}

/* --- COMPONENT: GRID --- */

.grid {
  display: grid;
  gap: var(--space-lg);
}

.grid-2 {
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

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

@media (max-width: 768px) {
  .grid-2, .grid-3, .grid-4 {
    grid-template-columns: 1fr;
  }
}

/* --- COMPONENT: SECTIONS --- */

section {
  margin: var(--space-xl) 0;
}

section > *:first-child {
  margin-top: 0;
}

/* --- COMPONENT: HEADER --- */

header {
  background: var(--color-brand-primary);
  color: white;
  padding: var(--space-2xl) var(--space-md);
}

header h1 {
  color: white;
}

header p {
  color: rgba(255, 255, 255, 0.85);
  font-size: var(--font-size-lg);
  line-height: var(--line-height-relaxed);
}

/* --- COMPONENT: HERO --- */

.hero {
  background: var(--color-brand-primary);
  color: white;
  padding: var(--space-3xl) var(--space-md);
  border-radius: var(--radius-xl);
  text-align: center;
  margin-bottom: var(--space-2xl);
}

.hero-content {
  max-width: 800px;
  margin: 0 auto;
}

.hero h1 {
  color: white;
  font-size: var(--font-size-4xl);
  margin-bottom: var(--space-md);
}

.hero .eyebrow {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: rgba(255, 255, 255, 0.7);
  margin-bottom: var(--space-lg);
  display: block;
}

.hero .subtitle {
  font-size: var(--font-size-xl);
  color: rgba(255, 255, 255, 0.9);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--space-xl);
}

.hero-cta {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  flex-wrap: wrap;
  margin-top: var(--space-xl);
}

.hero .button-primary {
  background: white;
  color: var(--color-brand-primary);
  font-weight: var(--font-weight-bold);
}

.hero .button-primary:hover {
  background: var(--color-neutral-100);
  color: var(--color-brand-primary);
}

.hero .button-ghost {
  color: white;
  border-color: white;
}

.hero .button-ghost:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: white;
}

/* --- COMPONENT: NAVIGATION --- */

.site-nav {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 50;
  padding: var(--space-md);
}

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

.site-nav-logo {
  display: none;
}

nav {
  display: flex;
  gap: var(--space-md);
  align-items: center;
  flex-wrap: wrap;
  justify-content: center;
}

nav a, nav button {
  padding: var(--space-sm) var(--space-md);
  text-decoration: none;
  transition: all var(--transition-normal);
  border: none;
  background: transparent;
  cursor: pointer;
  font-size: var(--font-size-base);
  color: inherit;
}

nav a:hover, nav button:hover {
  color: var(--color-brand-accent);
}

/* Hamburger menu (mobile) */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  border: none;
  background: transparent;
  cursor: pointer;
  padding: var(--space-sm);
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: currentColor;
  transition: all var(--transition-normal);
  transform-origin: center;
}

.nav-toggle.active span:nth-child(1) {
  transform: translateY(9px) rotate(45deg);
}

.nav-toggle.active span:nth-child(2) {
  opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
  transform: translateY(-9px) rotate(-45deg);
}

/* --- COMPONENT: EXPERTISE DOMAIN CARDS --- */

.expertise-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  border-left: 4px solid var(--color-brand-accent);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
}

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

.expertise-card h3 {
  margin-top: 0;
  font-size: var(--font-size-lg);
  color: var(--color-text-primary);
}

.expertise-card p {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
  margin-bottom: 0;
}

.expertise-card ul {
  margin-top: var(--space-md);
  padding-left: var(--space-lg);
}

.expertise-card li {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  margin-bottom: 4px;
}

/* --- COMPONENT: PROJECT CARD (FEATURED WORK) --- */

.project-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
  border: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  height: 100%;
}

.project-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-4px);
}

.project-card-image {
  width: 100%;
  height: 140px;
  background: var(--color-neutral-100);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-lg);
  color: var(--color-text-muted);
  overflow: hidden;
}

.project-card-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.project-card-content {
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.project-category {
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}

.project-card-title {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
  margin: 0 0 var(--space-sm) 0;
}

.project-card-status {
  display: flex;
  gap: var(--space-sm);
  margin-bottom: var(--space-md);
  flex-wrap: wrap;
}

.project-card-description {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--space-md);
  flex-grow: 1;
}

.project-card-footer {
  display: flex;
  gap: var(--space-sm);
  margin-top: auto;
  flex-wrap: wrap;
}

.project-card .button {
  font-size: var(--font-size-sm);
  padding: var(--space-sm) var(--space-md);
}

/* --- COMPONENT: CREDIBILITY STRIP --- */

.credibility-strip {
  background: var(--color-neutral-50);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-2xl) var(--space-md);
  margin: var(--space-lg) 0;
}

.credibility-strip h3 {
  text-align: center;
  font-size: var(--font-size-base);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--space-xl);
}

.domains-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-lg);
  max-width: 1200px;
  margin: 0 auto;
}

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

@media (max-width: 640px) {
  .domains-list {
    grid-template-columns: 1fr;
  }
}

.domain-item {
  text-align: center;
  padding: var(--space-md);
}

.domain-item h3 {
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-xs);
}

.domain-item p {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin: 0;
}

/* --- COMPONENT: SECTION HEADER --- */

.section-header {
  margin-bottom: var(--space-lg);
  border-bottom: 2px solid var(--color-border);
  padding-bottom: var(--space-lg);
}

.section-header h2 {
  margin-bottom: var(--space-sm);
}

.section-header p {
  color: var(--color-text-secondary);
  font-size: var(--font-size-lg);
  line-height: var(--line-height-relaxed);
  margin: 0;
}

/* --- COMPONENT: NARRATIVE CARD --- */

.narrative-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  border-left: 4px solid var(--color-brand-primary);
  box-shadow: var(--shadow-sm);
}

.narrative-text {
  font-size: var(--font-size-lg);
  line-height: var(--line-height-relaxed);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-lg);
}

.narrative-text:last-child {
  margin-bottom: 0;
}

/* --- COMPONENT: CENTERED CTA SECTION --- */

.cta-center {
  text-align: center;
}

.cta-intro {
  color: var(--color-text-muted);
  margin-bottom: var(--space-lg);
}

/* --- SKILLS PAGE COMPONENTS --- */
/* (Unified into global stylesheet for consistent single-stylesheet architecture) */

.skills-header {
  background: var(--color-brand-primary);
  color: white;
  padding: var(--space-3xl) var(--space-md);
  text-align: center;
}

.skills-header h1 {
  color: white;
  margin-bottom: var(--space-md);
}

.skills-header p {
  max-width: 900px;
  margin: var(--space-lg) auto 0;
  color: rgba(255, 255, 255, 0.85);
  font-size: var(--font-size-lg);
  line-height: var(--line-height-relaxed);
}

.skills-nav {
  max-width: 1200px;
  margin: var(--space-lg) auto 0;
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  flex-wrap: wrap;
}

.skills-nav a {
  color: white;
  border: 1px solid rgba(255, 255, 255, 0.35);
  padding: var(--space-sm) var(--space-md);
  border-radius: 999px;
  text-decoration: none;
  font-size: var(--font-size-sm);
  transition: all var(--transition-normal);
}

.skills-nav a:hover {
  background: rgba(255, 255, 255, 0.14);
  border-color: rgba(255, 255, 255, 0.5);
}

.skills-main {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--space-lg) var(--space-md) var(--space-2xl);
}

.summary-card {
  background: var(--color-surface);
  padding: var(--space-xl);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  margin-bottom: var(--space-lg);
  border: 1px solid var(--color-border);
}

.summary-card h2 {
  margin-top: 0;
  color: var(--color-text-primary);
  font-size: var(--font-size-2xl);
}

.legend {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-top: var(--space-lg);
}

.legend span {
  border: 1px solid var(--color-border);
  border-radius: 999px;
  padding: 6px 10px;
  background: var(--color-neutral-100);
  color: var(--color-text-secondary);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-medium);
}

/* --- SKILLS TREE VISUALIZATION --- */

.tree {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border);
  overflow-x: auto;
  margin-bottom: var(--space-lg);
}

.tree ul {
  padding-top: var(--space-lg);
  position: relative;
  display: flex;
  justify-content: center;
  gap: var(--space-md);
  margin: 0;
  list-style: none;
  flex-wrap: wrap;
}

.tree li {
  list-style-type: none;
  text-align: center;
  position: relative;
  padding: var(--space-lg) var(--space-sm) 0;
  min-width: 180px;
  flex: 0 1 auto;
}

.tree li::before,
.tree li::after {
  content: "";
  position: absolute;
  top: 0;
  right: 50%;
  border-top: 2px solid var(--color-border);
  width: 50%;
  height: 20px;
}

.tree li::after {
  right: auto;
  left: 50%;
  border-left: 2px solid var(--color-border);
}

.tree li:only-child::before,
.tree li:only-child::after {
  display: none;
}

.tree li:only-child {
  padding-top: 0;
}

.tree li:first-child::before,
.tree li:last-child::after {
  border: 0 none;
}

.tree li:last-child::before {
  border-right: 2px solid var(--color-border);
  border-radius: 0 8px 0 0;
}

.tree li:first-child::after {
  border-radius: 8px 0 0 0;
}

.tree ul ul::before {
  content: "";
  position: absolute;
  top: 0;
  left: 50%;
  border-left: 2px solid var(--color-border);
  width: 0;
  height: 20px;
}

.node {
  display: inline-block;
  background: var(--color-neutral-50);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-sm) var(--space-md);
  width: 100%;
  text-align: left;
  box-shadow: var(--shadow-xs);
  transition: all var(--transition-normal);
}

.node:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  background: var(--color-surface);
}

.node h3 {
  margin: 0 0 4px;
  font-size: var(--font-size-sm);
  color: var(--color-text-primary);
  font-weight: var(--font-weight-bold);
}

.node p {
  margin: 0;
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
  line-height: 1.3;
}

.node.root {
  background: var(--color-brand-primary);
  color: white;
  border-color: var(--color-brand-primary);
}

.node.root h3,
.node.root p {
  color: white;
}

.node.packaging {
  border-top: 4px solid #10b981;
}

.node.validation {
  border-top: 4px solid var(--color-brand-accent);
}

.node.simulation {
  border-top: 4px solid #8b5cf6;
}

.node.regulatory {
  border-top: 4px solid var(--color-amber);
}

.node.leadership {
  border-top: 4px solid #ef4444;
}

.details-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: var(--space-lg);
  margin-top: var(--space-2xl);
}

.detail-card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border);
  transition: all var(--transition-normal);
}

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

.detail-card h2 {
  margin-top: 0;
  color: var(--color-text-primary);
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--space-md);
}

.detail-card ul {
  margin-bottom: 0;
  padding-left: var(--space-lg);
}

.detail-card li {
  margin-bottom: var(--space-sm);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
}

.skills-footer {
  margin-top: var(--space-2xl);
  text-align: center;
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
}

.skills-footer a {
  color: var(--color-brand-accent);
  text-decoration: none;
  font-weight: var(--font-weight-semibold);
}

.skills-footer a:hover {
  color: var(--color-teal-dark);
}

/* Skills tree responsive behavior */
@media (max-width: 900px) {
  .tree ul {
    display: flex;
    flex-direction: column;
    padding-left: 0;
    gap: var(--space-md);
  }

  .tree li {
    min-width: 100%;
    padding-top: var(--space-md);
  }

  .tree li::before,
  .tree li::after,
  .tree ul ul::before {
    display: none;
  }

  .node {
    width: 100%;
  }
}

/* --- COMPONENT: FOOTER --- */

footer {
  background: var(--color-neutral-900);
  color: var(--color-neutral-300);
  padding: var(--space-2xl) var(--space-md);
  margin-top: var(--space-2xl);
  font-size: var(--font-size-sm);
  text-align: center;
}

footer a {
  color: var(--color-brand-accent);
}

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

.footer-links {
  font-size: var(--font-size-xs);
  margin-top: var(--space-md);
}

/* --- COMPONENT: DIVIDER --- */

hr {
  border: none;
  height: 1px;
  background: var(--color-border);
  margin: var(--space-2xl) 0;
}

/* --- RESPONSIVE DESIGN --- */

/* Tablet and up */
@media (min-width: 768px) {
  .site-nav-container {
    justify-content: center;
  }

  .nav-toggle {
    display: none;
  }
  
  .nav-menu {
    display: flex;
    justify-content: center;
    margin: 0 auto;
  }
}

/* Mobile */
@media (max-width: 767px) {
  .site-nav-container {
    justify-content: flex-end;
    position: relative;
  }

  body {
    font-size: var(--font-size-base);
  }
  
  h1 {
    font-size: clamp(1.875rem, 6vw, 2.25rem);
  }
  
  h2 {
    font-size: clamp(1.5rem, 5vw, 1.875rem);
  }
  
  h3 {
    font-size: clamp(1.25rem, 4vw, 1.5rem);
  }
  
  .nav-toggle {
    display: flex;
  }
  
  .nav-menu {
    display: none;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    padding: var(--space-md) 0;
    width: 100%;
    z-index: 100;
  }
  
  .nav-menu.active {
    display: flex;
  }
  
  .nav-menu a, .nav-menu button {
    padding: var(--space-md) var(--space-lg);
    border-bottom: 1px solid var(--color-border);
    text-align: left;
  }
  
  .nav-menu a:last-child, .nav-menu button:last-child {
    border-bottom: none;
  }
  
  .hero {
    padding: var(--space-2xl) var(--space-md);
  }
  
  .hero h1 {
    font-size: clamp(1.875rem, 6vw, 2.25rem);
  }
  
  .domains-list {
    grid-template-columns: 1fr;
  }
  
  .grid-2, .grid-3, .grid-4 {
    grid-template-columns: 1fr;
  }
}

/* Large screens */
@media (min-width: 1200px) {
  .container {
    padding: 0 var(--space-lg);
  }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* Print styles */
@media print {
  body {
    background: white;
  }
  
  .no-print {
    display: none;
  }
}

/* Featured tools presentation */
.featured-tools-container {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-lg);
  max-width: 100%;
  margin: 0 auto;
}

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

@media (max-width: 640px) {
  .featured-tools-container {
    grid-template-columns: 1fr;
  }
}

.featured-tools-container.multi-project {
  max-width: 100%;
  display: grid;
  gap: var(--space-lg);
}

.svg-placeholder {
  opacity: 0.3;
}