/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
  /* Colors */
  --color-bg: #FAFAFA;
  --color-bg-card: #FFFFFF;
  --color-text: #1F2937;
  --color-text-light: #6B7280;
  --color-text-lighter: #9CA3AF;
  --color-accent: #0D9488;
  --color-accent-hover: #0F766E;
  --color-accent-light: rgba(13, 148, 136, 0.1);
  --color-accent-warm: #F97316;
  --color-border: #E5E7EB;
  --color-border-light: #F3F4F6;

  /* Color aliases for legacy styles */
  --color-text-primary: #1F2937;
  --color-text-secondary: #6B7280;
  --color-text-muted: #9CA3AF;
  --color-background-subtle: #F3F4F6;
  --color-background-warm: #FFF7ED;

  /* Typography */
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  /* Spacing */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2rem;
  --space-xl: 4rem;
  --space-2xl: 6rem;

  /* Sizing */
  --max-width: 800px;
  --nav-height: 64px;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 200ms ease;
  --transition-slow: 300ms ease;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.05), 0 2px 4px rgba(0, 0, 0, 0.03);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.05), 0 4px 6px rgba(0, 0, 0, 0.03);
}

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  margin: 0;
  padding: 0;
  padding-top: var(--nav-height);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Subtle animated background accent */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--color-accent) 0%, var(--color-accent-warm) 50%, var(--color-accent) 100%);
    background-size: 200% 100%;
    animation: gradientShift 8s ease-in-out infinite;
    z-index: 100;
}

@keyframes gradientShift {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

/* Fade in animation for content */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

/* Main */
main {
  padding: var(--space-xl) 0;
}

/* Typography */
h1, h2, h3 {
    font-weight: 600;
    line-height: 1.2;
    letter-spacing: -0.02em;
}

h1 {
    font-size: 3.5rem;
    margin-bottom: var(--space-xs);
}

h2 {
    font-size: 0.8125rem;
    margin-bottom: var(--space-lg);
    color: var(--color-accent);
    text-transform: uppercase;
    letter-spacing: 0.12em;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

h2::after {
    content: '';
    flex: 1;
    height: 1px;
    background: linear-gradient(90deg, var(--color-border) 0%, transparent 100%);
}

h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-text-primary);
}

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

.lead {
    font-size: 1.1875rem;
    line-height: 1.75;
    color: var(--color-text-secondary);
    font-weight: 400;
}

/* Hero */
.hero {
  position: relative;
  min-height: 70vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  overflow: hidden;
}

#particle-canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 1;
  padding: var(--space-xl) var(--space-md);
}

.hero .name {
  font-size: 3rem;
  font-weight: 700;
  margin: 0 0 var(--space-xs);
  color: var(--color-text);
}

.hero .title {
  font-size: 1.25rem;
  font-weight: 500;
  color: var(--color-text-light);
  margin: 0 0 var(--space-sm);
}

.hero .tagline {
  font-size: 1.125rem;
  color: var(--color-text-light);
  margin: 0 0 var(--space-lg);
  max-width: 400px;
}

.hero-cta {
  display: flex;
  gap: var(--space-sm);
  justify-content: center;
  flex-wrap: wrap;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  padding: 0.75rem 1.5rem;
  font-size: 0.9375rem;
  font-weight: 500;
  text-decoration: none;
  border-radius: 6px;
  transition: all var(--transition-base);
}

.btn-primary {
  background: var(--color-accent);
  color: white;
}

.btn-primary:hover {
  background: var(--color-accent-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

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

.btn-secondary:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

/* Sections */
section {
    margin-bottom: var(--space-2xl);
    animation: fadeInUp 0.6s ease-out;
    animation-fill-mode: both;
}

section:nth-of-type(1) { animation-delay: 0.1s; }
section:nth-of-type(2) { animation-delay: 0.2s; }
section:nth-of-type(3) { animation-delay: 0.3s; }
section:nth-of-type(4) { animation-delay: 0.4s; }

section:last-of-type {
    margin-bottom: var(--space-xl);
}

/* Section Dividers */
.section-divider {
  position: relative;
  height: 1px;
  background: var(--color-border-light);
  margin: var(--space-xl) 0;
}

.section-divider::before,
.section-divider::after {
  content: '';
  position: absolute;
  top: -3px;
  width: 1px;
  height: 7px;
  background: var(--color-border);
}

.section-divider::before {
  left: 0;
}

.section-divider::after {
  right: 0;
}

/* Section heading styling */
section h2 {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--color-text);
  margin: 0 0 var(--space-md);
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid var(--color-border-light);
  position: relative;
}

section h2::after {
  content: '';
  position: absolute;
  bottom: -1px;
  left: 0;
  width: 40px;
  height: 2px;
  background: var(--color-accent);
}

/* About (brief) */
.about-text {
  font-size: 1.0625rem;
  line-height: 1.7;
  color: var(--color-text);
  margin: 0 0 var(--space-md);
}

.about-text strong {
  font-weight: 600;
}

.about-link {
  font-size: 0.9375rem;
  color: var(--color-accent);
  text-decoration: none;
  font-weight: 500;
  transition: color var(--transition-fast);
}

.about-link:hover {
  color: var(--color-accent-hover);
}

/* Timeline */
.timeline {
  position: relative;
  padding-left: var(--space-lg);
}

.timeline::before {
  content: '';
  position: absolute;
  left: 6px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: var(--color-border);
}

.timeline-item {
  position: relative;
  padding-bottom: var(--space-lg);
}

.timeline-item:last-child {
  padding-bottom: 0;
}

.timeline-marker {
  position: absolute;
  left: calc(-1 * var(--space-lg) + 2px);
  top: 6px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--color-border);
  border: 2px solid var(--color-bg);
  transition: all var(--transition-fast);
}

.timeline-item.current .timeline-marker {
  background: var(--color-accent);
  box-shadow: 0 0 0 3px var(--color-accent-light);
}

.timeline-item:hover .timeline-marker {
  transform: scale(1.2);
}

.timeline-date {
  font-size: 0.8125rem;
  font-family: var(--font-mono);
  color: var(--color-text-lighter);
  margin-bottom: var(--space-xs);
}

.timeline-content h3 {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--color-text);
  margin: 0 0 0.25rem;
}

.timeline-content .organization {
  font-size: 0.9375rem;
  color: var(--color-accent);
  margin: 0 0 var(--space-xs);
}

.timeline-content .description {
  font-size: 0.9375rem;
  color: var(--color-text-light);
  margin: 0;
  line-height: 1.6;
}

/* Skills Bar Chart */
.skills-chart {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.skill-category {
  display: grid;
  grid-template-columns: 100px 1fr;
  gap: var(--space-sm);
  align-items: start;
}

.category-label {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--color-text-light);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding-top: 0.25rem;
}

.skill-bars {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.skill-bar-item {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: var(--space-sm);
  align-items: center;
}

.skill-name {
  font-size: 0.9375rem;
  font-family: var(--font-mono);
  color: var(--color-text);
}

.skill-bar {
  height: 8px;
  background: var(--color-border-light);
  border-radius: 4px;
  overflow: hidden;
  position: relative;
}

.skill-bar-fill {
  height: 100%;
  width: var(--skill-level);
  background: var(--color-accent);
  border-radius: 4px;
  transition: width 0.8s ease-out, background var(--transition-fast);
  position: relative;
}

.skill-bar-item:hover .skill-bar-fill {
  background: var(--color-accent-hover);
}

.skill-bar-fill::after {
  content: attr(data-years);
  position: absolute;
  right: 0;
  top: -24px;
  font-size: 0.75rem;
  font-family: var(--font-mono);
  color: var(--color-text-lighter);
  opacity: 0;
  transition: opacity var(--transition-fast);
  white-space: nowrap;
}

.skill-bar-item:hover .skill-bar-fill::after {
  opacity: 1;
}

/* Navigation */
.main-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(250, 250, 250, 0.9);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border-light);
  z-index: 100;
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-md);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--color-text);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

.nav-links {
  display: flex;
  gap: var(--space-md);
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  font-size: 0.9375rem;
  color: var(--color-text-light);
  text-decoration: none;
  padding: var(--space-xs) 0;
  position: relative;
  transition: color var(--transition-fast);
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-accent);
  transition: width var(--transition-base);
}

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

.nav-links a.active::after,
.nav-links a:hover::after {
  width: 100%;
}

/* Page Header (for non-home pages) */
.page-header {
    margin-bottom: var(--space-2xl);
    animation: fadeInUp 0.6s ease-out;
}

.page-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    letter-spacing: -0.03em;
    margin-bottom: var(--space-sm);
    color: var(--color-text-primary);
}

.page-header .lead {
    max-width: 600px;
}

.page-intro {
    font-size: 1.125rem;
    color: var(--color-text-light);
    margin: 0;
}

/* Tool Intro */
.tool-intro {
    margin-bottom: var(--space-xl);
}

.tool-intro h2 {
    margin-bottom: var(--space-md);
}

.tool-intro p {
    max-width: 680px;
}

/* Explainer Section */
.explainer-section {
    margin-bottom: var(--space-2xl);
}

.explainer-section h2 {
    margin-bottom: var(--space-md);
}

.explainer-content {
    background: var(--color-background-subtle);
    border-radius: 12px;
    padding: var(--space-lg);
    border: 1px solid var(--color-border);
}

.explainer-lead {
    font-size: 1.125rem;
    line-height: 1.7;
    color: var(--color-text-primary);
    margin-bottom: var(--space-lg);
}

.approach-explainer {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-md);
    margin-bottom: var(--space-lg);
}

.approach-card {
    background: var(--color-background);
    border-radius: 10px;
    padding: var(--space-md);
    border: 1px solid var(--color-border);
    transition: all var(--transition-base);
}

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

.approach-card h3 {
    font-size: 1.0625rem;
    margin-bottom: var(--space-sm);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.frequentist-card h3::before {
    content: '';
    width: 12px;
    height: 12px;
    background: var(--color-accent);
    border-radius: 2px;
}

.bayesian-card h3::before {
    content: '';
    width: 12px;
    height: 12px;
    background: var(--color-accent-warm);
    border-radius: 50%;
}

.approach-card p {
    font-size: 0.9375rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--space-sm);
    line-height: 1.65;
}

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

.approach-analogy {
    background: var(--color-background-warm);
    padding: var(--space-sm);
    border-radius: 6px;
    font-style: italic;
    border-left: 3px solid var(--color-border-warm);
}

.approach-strength {
    font-size: 0.875rem !important;
    padding: var(--space-sm);
    background: rgba(3, 105, 161, 0.05);
    border-radius: 6px;
    border-left: 3px solid var(--color-accent);
    font-style: normal !important;
}

.bayesian-card .approach-strength {
    background: rgba(234, 88, 12, 0.05);
    border-left-color: var(--color-accent-warm);
}

.why-both {
    padding-top: var(--space-lg);
    border-top: 1px solid var(--color-border);
}

.why-both h3 {
    font-size: 1.0625rem;
    margin-bottom: var(--space-sm);
    color: var(--color-text-primary);
}

.why-both p {
    font-size: 0.9375rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--space-sm);
    line-height: 1.65;
}

.why-both ul {
    list-style: none;
    margin: var(--space-sm) 0;
}

.why-both li {
    font-size: 0.9375rem;
    color: var(--color-text-secondary);
    padding: 0.375rem 0;
    padding-left: 1.5rem;
    position: relative;
    line-height: 1.6;
}

.why-both li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0.75rem;
    width: 8px;
    height: 8px;
    background: var(--color-accent);
    border-radius: 50%;
}

.calculator-intro-section {
    margin-bottom: var(--space-lg);
}

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

/* Calculator Tabs */
.calculator-tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: var(--space-lg);
    border-bottom: 1px solid var(--color-border);
    padding-bottom: var(--space-sm);
}

.tab-button {
    padding: 0.75rem 1.5rem;
    font-size: 0.9375rem;
    font-weight: 500;
    font-family: var(--font-sans);
    color: var(--color-text-muted);
    background: none;
    border: none;
    border-radius: 8px 8px 0 0;
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
}

.tab-button:hover {
    color: var(--color-text-primary);
    background: var(--color-background-subtle);
}

.tab-button.active {
    color: var(--color-accent);
    background: rgba(3, 105, 161, 0.08);
}

.tab-button.active::after {
    content: '';
    position: absolute;
    bottom: -9px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--color-accent);
}

/* Calculator Panels */
.calculator-panel {
    display: none;
    animation: fadeInUp 0.4s ease-out;
}

.calculator-panel.active {
    display: block;
}

.calculator-intro {
    margin-bottom: var(--space-lg);
    padding: var(--space-md);
    background: var(--color-background-subtle);
    border-radius: 10px;
    border-left: 3px solid var(--color-accent);
}

.calculator-intro h3 {
    margin-bottom: var(--space-sm);
    font-size: 1.125rem;
}

.calculator-intro p {
    margin-bottom: var(--space-xs);
    color: var(--color-text-secondary);
}

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

/* Calculator Form */
.calculator-form {
    margin-bottom: var(--space-lg);
}

.form-group {
    margin-bottom: var(--space-lg);
    padding-bottom: var(--space-lg);
    border-bottom: 1px solid var(--color-border);
}

.form-group:last-of-type {
    border-bottom: none;
    margin-bottom: var(--space-md);
}

.form-group label {
    display: block;
    margin-bottom: var(--space-sm);
}

.question-main {
    display: block;
    font-size: 1.0625rem;
    font-weight: 600;
    color: var(--color-text-primary);
    margin-bottom: 0.375rem;
    line-height: 1.4;
}

.question-detail {
    display: block;
    font-size: 0.9375rem;
    color: var(--color-text-secondary);
    line-height: 1.6;
    font-weight: 400;
}

.input-with-unit {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-top: var(--space-sm);
}

.input-with-unit input {
    width: 120px;
    padding: 0.75rem 1rem;
    font-size: 1.125rem;
    font-family: var(--font-mono);
    font-weight: 500;
    border: 2px solid var(--color-border);
    border-radius: 8px;
    transition: all var(--transition-fast);
}

.input-with-unit input:focus {
    outline: none;
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px rgba(3, 105, 161, 0.1);
}

.input-with-unit .unit {
    font-size: 0.9375rem;
    color: var(--color-text-muted);
    font-weight: 500;
}

.form-group select {
    width: 100%;
    max-width: 400px;
    padding: 0.75rem 1rem;
    font-size: 1rem;
    font-family: var(--font-sans);
    border: 2px solid var(--color-border);
    border-radius: 8px;
    background: white;
    cursor: pointer;
    transition: all var(--transition-fast);
    margin-top: var(--space-sm);
}

.form-group select:focus {
    outline: none;
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px rgba(3, 105, 161, 0.1);
}

.input-hint {
    font-size: 0.8125rem;
    color: var(--color-text-muted);
    margin-top: 0.5rem;
}

.calculated-value {
    font-size: 0.875rem;
    color: var(--color-accent);
    margin-top: 0.5rem;
    font-weight: 500;
    font-family: var(--font-mono);
}

/* Calculate Button */
.calculate-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 1rem 2rem;
    font-size: 1rem;
    font-weight: 600;
    font-family: var(--font-sans);
    color: white;
    background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-accent-light) 100%);
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all var(--transition-base);
    box-shadow: var(--shadow-md);
}

.calculate-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.calculate-btn:active {
    transform: translateY(0);
}

/* Calculator Result */
.calculator-result {
    padding: var(--space-lg);
    background: linear-gradient(135deg, var(--color-background-subtle) 0%, var(--color-background-warm) 100%);
    border-radius: 12px;
    text-align: center;
    margin-bottom: var(--space-lg);
    border: 1px solid var(--color-border);
    opacity: 0;
    transform: translateY(10px);
    transition: all var(--transition-base);
}

.calculator-result.visible {
    opacity: 1;
    transform: translateY(0);
}

.result-header {
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-text-muted);
    margin-bottom: var(--space-xs);
}

.result-number {
    font-size: 3.5rem;
    font-weight: 700;
    font-family: var(--font-mono);
    color: var(--color-accent);
    letter-spacing: -0.03em;
    line-height: 1.1;
}

.result-label {
    font-size: 1.125rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--space-sm);
}

.result-total {
    font-size: 1rem;
    color: var(--color-text-muted);
    padding-top: var(--space-sm);
    border-top: 1px solid var(--color-border);
    display: inline-block;
}

.result-total span {
    font-weight: 600;
    color: var(--color-text-primary);
}

.result-note {
    font-size: 0.8125rem;
    color: var(--color-text-muted);
    margin-top: var(--space-sm);
    font-style: italic;
}

.result-explanation {
    font-size: 0.9375rem;
    color: var(--color-text-secondary);
    margin-top: var(--space-md);
    padding-top: var(--space-md);
    border-top: 1px solid var(--color-border);
    text-align: left;
    line-height: 1.6;
}

/* Method Details */
.method-details {
    padding: var(--space-md);
    background: var(--color-background-subtle);
    border-radius: 10px;
    margin-bottom: var(--space-2xl);
}

.method-details h4 {
    font-size: 0.9375rem;
    font-weight: 600;
    margin-bottom: var(--space-sm);
    color: var(--color-text-primary);
}

.method-details p {
    font-size: 0.9375rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--space-sm);
}

.method-details ul {
    list-style: none;
    margin: var(--space-sm) 0;
}

.method-details li {
    font-size: 0.9375rem;
    color: var(--color-text-secondary);
    padding-left: 1.25rem;
    position: relative;
    margin-bottom: 0.375rem;
}

.method-details li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0.5rem;
    width: 6px;
    height: 6px;
    background: var(--color-accent);
    border-radius: 50%;
}

/* Comparison Section */
.comparison-section {
    margin-top: var(--space-xl);
    padding-top: var(--space-xl);
    border-top: 1px solid var(--color-border);
}

.comparison-section h2 {
    margin-bottom: var(--space-lg);
}

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

.comparison-card {
    padding: var(--space-md);
    background: var(--color-background-subtle);
    border-radius: 10px;
    border: 1px solid var(--color-border);
}

.comparison-card h4 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: var(--space-sm);
    color: var(--color-accent);
}

.comparison-card ul {
    list-style: none;
}

.comparison-card li {
    font-size: 0.9375rem;
    color: var(--color-text-secondary);
    padding: 0.375rem 0;
    padding-left: 1rem;
    position: relative;
}

.comparison-card li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--color-accent);
}

.comparison-note {
    font-size: 0.9375rem;
    color: var(--color-text-muted);
    font-style: italic;
}

/* Tools Preview */
.tools-preview {
  margin-bottom: var(--space-xl);
}

.section-intro {
  font-size: 1rem;
  color: var(--color-text-light);
  margin: 0 0 var(--space-md);
}

.tool-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-md);
}

.tool-card {
  display: block;
  padding: var(--space-md);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  text-decoration: none;
  transition: all var(--transition-base);
}

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

.tool-icon {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-accent-light);
  border-radius: 8px;
  color: var(--color-accent);
  margin-bottom: var(--space-sm);
}

.tool-card h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-text);
  margin: 0 0 var(--space-xs);
}

.tool-card p {
  font-size: 0.9375rem;
  color: var(--color-text-light);
  margin: 0 0 var(--space-sm);
  line-height: 1.5;
}

.tool-link {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-accent);
}

/* About Page */
.about-page section {
  margin-bottom: var(--space-xl);
}

.about-intro p {
  font-size: 1.0625rem;
  line-height: 1.7;
  color: var(--color-text);
  margin: 0 0 var(--space-md);
}

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

.about-intro strong {
  font-weight: 600;
}

.about-contact .contact-links {
  display: flex;
  gap: var(--space-sm);
  margin-top: var(--space-md);
}

/* Education timeline items (hollow markers) */
.timeline-item.education .timeline-marker {
  background: var(--color-bg);
  border: 2px solid var(--color-border);
}

/* Footer */
footer {
  padding: var(--space-lg) 0;
  border-top: 1px solid var(--color-border-light);
  text-align: center;
}

.footer-text {
  font-size: 0.875rem;
  color: var(--color-text-lighter);
  margin: 0;
}

/* Simplified Calculator Styles */
.calculator-card {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    padding: var(--space-lg);
    max-width: 600px;
}

.calc-question {
    margin-bottom: var(--space-lg);
}

.calc-label {
    display: block;
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: var(--space-sm);
}

.measurement-options {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-sm);
}

.measurement-btn {
    padding: var(--space-sm) var(--space-md);
    font-size: 1rem;
    font-family: var(--font-body);
    font-weight: 500;
    color: var(--color-text-light);
    background: var(--color-bg);
    border: 2px solid var(--color-border);
    border-radius: 8px;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.measurement-btn:hover {
    border-color: var(--color-accent);
    color: var(--color-text);
}

.measurement-btn.selected {
    background: var(--color-accent);
    border-color: var(--color-accent);
    color: white;
}

.calc-hint {
    font-size: 0.9375rem;
    color: var(--color-text-light);
    margin-bottom: var(--space-sm);
}

.input-row {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}

.calc-input {
    width: 100px;
    padding: 0.75rem 1rem;
    font-size: 1.25rem;
    font-family: var(--font-mono);
    font-weight: 500;
    border: 2px solid var(--color-border);
    border-radius: 8px;
    transition: all var(--transition-fast);
}

.calc-input:focus {
    outline: none;
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px rgba(13, 148, 136, 0.1);
}

.input-suffix {
    font-size: 1.125rem;
    color: var(--color-text-light);
    font-weight: 500;
}

.use-default-btn {
    margin-top: var(--space-sm);
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
    font-family: var(--font-body);
    color: var(--color-accent);
    background: transparent;
    border: 1px solid var(--color-accent);
    border-radius: 6px;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.use-default-btn:hover {
    background: var(--color-accent);
    color: white;
}

.calc-input-wide {
    width: 140px;
}

.calc-result {
    margin-top: var(--space-lg);
    padding: var(--space-lg);
    background: linear-gradient(135deg, var(--color-bg) 0%, rgba(13, 148, 136, 0.05) 100%);
    border-radius: 12px;
    border: 1px solid var(--color-border);
    text-align: center;
}

.result-main {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-xs);
}

.result-intro,
.result-outro {
    font-size: 1rem;
    color: var(--color-text-light);
}

.result-number {
    font-size: 3rem;
    font-weight: 700;
    font-family: var(--font-mono);
    color: var(--color-accent);
    line-height: 1.1;
}

.result-example {
    font-size: 0.9375rem;
    color: var(--color-text-light);
    margin-top: var(--space-sm);
    margin-bottom: 0;
}

.result-warning {
    margin-top: var(--space-md);
    padding: var(--space-sm);
    background: rgba(249, 115, 22, 0.1);
    border-radius: 8px;
    font-size: 0.9375rem;
    color: var(--color-text);
    border-left: 3px solid var(--color-accent-warm);
}

.learn-link {
    display: inline-block;
    margin-top: var(--space-md);
    font-size: 0.9375rem;
    color: var(--color-accent);
    text-decoration: none;
    font-weight: 500;
}

.learn-link:hover {
    text-decoration: underline;
}

.advanced-toggle {
    margin-top: var(--space-lg);
    text-align: center;
}

.advanced-btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    padding: var(--space-xs) var(--space-sm);
    font-size: 0.9375rem;
    font-family: var(--font-body);
    color: var(--color-text-light);
    background: transparent;
    border: none;
    cursor: pointer;
    transition: color var(--transition-fast);
}

.advanced-btn:hover {
    color: var(--color-accent);
}

.advanced-btn .chevron {
    transition: transform var(--transition-fast);
}

.advanced-btn.open .chevron {
    transform: rotate(180deg);
}

.advanced-panel {
    margin-top: var(--space-md);
    padding: var(--space-md);
    background: var(--color-bg);
    border-radius: 8px;
    border: 1px solid var(--color-border);
}

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

.advanced-option:last-of-type {
    margin-bottom: var(--space-sm);
}

.advanced-label {
    display: block;
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--color-text);
    margin-bottom: var(--space-xs);
}

.advanced-select {
    width: 100%;
    padding: 0.625rem 1rem;
    font-size: 0.9375rem;
    font-family: var(--font-body);
    color: var(--color-text);
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: 6px;
    cursor: pointer;
    transition: border-color var(--transition-fast);
}

.advanced-select:focus {
    outline: none;
    border-color: var(--color-accent);
}

.advanced-note {
    font-size: 0.8125rem;
    color: var(--color-text-lighter);
    margin: 0;
    font-style: italic;
}

/* Learn page styles */
.learn-content {
    max-width: 680px;
}

.learn-section {
    margin-bottom: var(--space-xl);
}

.learn-section h2 {
    font-size: 1.25rem;
    margin-bottom: var(--space-sm);
}

.learn-section p {
    font-size: 1.0625rem;
    line-height: 1.7;
    color: var(--color-text);
}

.learn-section ul {
    margin: var(--space-sm) 0;
    padding-left: var(--space-md);
}

.learn-section li {
    font-size: 1.0625rem;
    line-height: 1.7;
    color: var(--color-text);
    margin-bottom: var(--space-sm);
}

.mistake-card {
    padding: var(--space-md);
    background: var(--color-bg);
    border-radius: 8px;
    border-left: 3px solid var(--color-accent);
    margin: var(--space-md) 0;
}

.mistake-card h3 {
    font-size: 1rem;
    margin-bottom: var(--space-xs);
    color: var(--color-text);
}

.mistake-card p {
    margin: 0;
    color: var(--color-text-light);
}

/* Responsive Design */
@media (max-width: 768px) {
    :root {
        --spacing-xl: 2.5rem;
        --spacing-2xl: 3.5rem;
    }

    .container {
        padding: 0 var(--space-sm);
    }

    .nav-container {
        height: 48px;
    }

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

    .nav-links a {
        padding: 0.375rem 0.75rem;
        font-size: 0.875rem;
    }

    .hero .name {
        font-size: 2.25rem;
    }

    .hero .tagline {
        font-size: 1rem;
    }

    .hero-cta {
        flex-direction: column;
        align-items: center;
    }

    .skill-category {
        grid-template-columns: 1fr;
    }

    .skill-bar-item {
        grid-template-columns: 100px 1fr;
    }

    .page-header h1 {
        font-size: 1.75rem;
    }

    .calculator-tabs {
        gap: 0.25rem;
    }

    .tab-button {
        padding: 0.625rem 1rem;
        font-size: 0.875rem;
    }

    .input-with-unit input {
        width: 100px;
    }

    .result-number {
        font-size: 2.5rem;
    }

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

    .approach-explainer {
        grid-template-columns: 1fr;
    }

    .explainer-content {
        padding: var(--space-md);
    }

    .explainer-lead {
        font-size: 1rem;
    }

    .name {
        font-size: 2.5rem;
    }

    .title {
        font-size: 1.25rem;
    }

    .lead {
        font-size: 1.0625rem;
    }

    .calculator-card {
        padding: var(--space-md);
    }

    .measurement-options {
        grid-template-columns: 1fr 1fr;
    }

    .advanced-panel {
        padding: var(--space-sm);
    }
}

@media (max-width: 480px) {
    :root {
        --space-xl: 2.5rem;
    }

    .hero {
        min-height: 60vh;
    }

    .hero .name {
        font-size: 1.875rem;
    }

    .nav-links {
        gap: var(--space-sm);
    }

    .nav-links a {
        font-size: 0.875rem;
    }

    .btn {
        width: 100%;
        justify-content: center;
    }

    .about-contact .contact-links {
        flex-direction: column;
    }

    .name {
        font-size: 2rem;
    }

    .title {
        font-size: 1.125rem;
    }

    h2::after {
        display: none;
    }

    .measurement-options {
        grid-template-columns: 1fr;
    }

    .calc-input-wide {
        width: 120px;
    }
}

/* Scroll Animations */
.animate-on-scroll {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.animate-on-scroll.in-view {
  opacity: 1;
  transform: translateY(0);
}

/* Smooth scrolling */
@media (prefers-reduced-motion: no-preference) {
    html {
        scroll-behavior: smooth;
    }
}

/* Reduced motion preference */
@media (prefers-reduced-motion: reduce) {
    .animate-on-scroll {
        opacity: 1;
        transform: none;
        transition: none;
    }

    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Print Styles */
@media print {
    body {
        font-size: 12pt;
        background: white;
    }

    body::before {
        display: none;
    }

    .container {
        max-width: 100%;
        padding: 0;
    }

    section {
        page-break-inside: avoid;
        animation: none;
    }

    .contact-links a::before {
        display: none;
    }

    .name {
        background: none;
        -webkit-text-fill-color: var(--color-text-primary);
        color: var(--color-text-primary);
    }
}