/* ==========================================================================
   100 Calculators — Design System
   Clean SaaS meets Neobrutalist aesthetic
   Mobile-first, high contrast, absolute simplicity
   ========================================================================== */

/* ---------- Google Fonts ---------- */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&family=JetBrains+Mono:wght@400;500;600;700&display=swap');

/* ---------- Design Tokens ---------- */
:root {
  /* Colors */
  --bg:              #f0f2f5;
  --bg-alt:          #e4e7ec;
  --card-bg:         #ffffff;
  --primary:         #2563eb;
  --primary-hover:   #1d4ed8;
  --primary-light:   #dbeafe;
  --secondary:       #7c3aed;
  --secondary-light: #ede9fe;
  --accent:          #f59e0b;
  --accent-light:    #fef3c7;
  --success:         #059669;
  --success-light:   #d1fae5;
  --warning:         #d97706;
  --warning-light:   #fef3c7;
  --danger:          #dc2626;
  --danger-light:    #fee2e2;
  --text:            #111827;
  --text-secondary:  #6b7280;
  --text-muted:      #9ca3af;
  --border:          #e5e7eb;
  --border-strong:   #d1d5db;

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

  /* Spacing */
  --space-xs:   4px;
  --space-sm:   8px;
  --space-md:   16px;
  --space-lg:   24px;
  --space-xl:   32px;
  --space-2xl:  48px;
  --space-3xl:  64px;

  /* Borders & Shadows */
  --radius-sm:  8px;
  --radius-md:  12px;
  --radius-lg:  16px;
  --radius-xl:  20px;
  --border-w:   2px;
  --shadow:     0 1px 3px rgba(0,0,0,0.08), 0 4px 12px rgba(0,0,0,0.06);
  --shadow-md:  0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -2px rgba(0,0,0,0.06);
  --shadow-lg:  0 10px 25px -3px rgba(0,0,0,0.1), 0 4px 10px -4px rgba(0,0,0,0.05);
  --shadow-neo: 4px 4px 0px rgba(0,0,0,0.15);
  --shadow-neo-lg: 6px 6px 0px rgba(0,0,0,0.12);

  /* Transitions */
  --ease:       cubic-bezier(0.4, 0, 0.2, 1);
  --duration:   200ms;
}

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

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

body {
  font-family: var(--font-body);
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  min-height: 100vh;
}

img { max-width: 100%; display: block; }
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ---------- Layout ---------- */
.container {
  width: 100%;
  max-width: 800px;
  margin: 0 auto;
  padding: 0 var(--space-md);
}

.container--wide {
  max-width: 1100px;
}

/* ---------- Site Header ---------- */
.site-header {
  background: var(--card-bg);
  border-bottom: var(--border-w) solid var(--border);
  padding: var(--space-md) 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
}

.site-logo {
  font-family: var(--font-mono);
  font-weight: 800;
  font-size: 1.1rem;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  text-decoration: none;
}

.site-logo:hover { text-decoration: none; }

.site-logo .logo-icon {
  width: 32px;
  height: 32px;
  background: var(--primary);
  border-radius: var(--radius-sm);
  border: var(--border-w) solid var(--text);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 0.85rem;
  box-shadow: 2px 2px 0 var(--text);
}

.site-nav {
  display: flex;
  gap: var(--space-md);
  align-items: center;
}

.site-nav a {
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.9rem;
  transition: color var(--duration) var(--ease);
}

.site-nav a:hover {
  color: var(--text);
  text-decoration: none;
}

/* ---------- Page Header ---------- */
.page-header {
  text-align: center;
  padding: var(--space-2xl) 0 var(--space-xl);
}

.page-header .badge {
  display: inline-block;
  background: var(--primary-light);
  color: var(--primary);
  font-weight: 600;
  font-size: 0.8rem;
  padding: var(--space-xs) var(--space-md);
  border-radius: 99px;
  margin-bottom: var(--space-md);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.page-header h1 {
  font-size: clamp(1.8rem, 5vw, 2.8rem);
  font-weight: 900;
  line-height: 1.15;
  margin-bottom: var(--space-md);
  letter-spacing: -0.02em;
}

.page-header .subtitle {
  font-size: clamp(1rem, 2.5vw, 1.2rem);
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
  line-height: 1.5;
}

/* ---------- Calculator Card ---------- */
.calc-card {
  background: var(--card-bg);
  border: var(--border-w) solid var(--border-strong);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  box-shadow: var(--shadow-neo);
  margin-bottom: var(--space-xl);
  position: relative;
}

.calc-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--primary), var(--secondary));
  border-radius: var(--radius-lg) var(--radius-lg) 0 0;
}

.calc-card h2 {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-md);
  border-bottom: 1px solid var(--border);
}

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

.form-group label {
  display: block;
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: var(--space-sm);
  color: var(--text);
}

.form-group .hint {
  display: block;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: var(--space-xs);
}

.form-row {
  display: grid;
  gap: var(--space-md);
  grid-template-columns: 1fr;
}

@media (min-width: 480px) {
  .form-row { grid-template-columns: 1fr 1fr; }
}

@media (min-width: 640px) {
  .form-row--3 { grid-template-columns: 1fr 1fr 1fr; }
}

/* Inputs */
input[type="number"],
input[type="text"],
select {
  width: 100%;
  height: 52px;
  padding: 0 var(--space-md);
  font-family: var(--font-mono);
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--text);
  background: var(--bg);
  border: var(--border-w) solid var(--border-strong);
  border-radius: var(--radius-md);
  transition: border-color var(--duration) var(--ease), box-shadow var(--duration) var(--ease);
  appearance: none;
  -webkit-appearance: none;
  -moz-appearance: textfield;
}

input[type="number"]::-webkit-inner-spin-button,
input[type="number"]::-webkit-outer-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

input:focus,
select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-light);
  background: var(--card-bg);
}

select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='%236b7280' viewBox='0 0 16 16'%3E%3Cpath d='M4.646 5.646a.5.5 0 01.708 0L8 8.293l2.646-2.647a.5.5 0 01.708.708l-3 3a.5.5 0 01-.708 0l-3-3a.5.5 0 010-.708z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 14px center;
  padding-right: 40px;
  cursor: pointer;
}

/* Range Sliders */
input[type="range"] {
  -webkit-appearance: none;
  width: 100%;
  height: 8px;
  background: var(--bg-alt);
  border-radius: 4px;
  outline: none;
  margin: var(--space-sm) 0;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 24px;
  height: 24px;
  background: var(--primary);
  border: 3px solid var(--card-bg);
  border-radius: 50%;
  cursor: pointer;
  box-shadow: 0 2px 4px rgba(0,0,0,0.2);
  transition: transform var(--duration) var(--ease);
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.15);
}

input[type="range"]::-moz-range-thumb {
  width: 24px;
  height: 24px;
  background: var(--primary);
  border: 3px solid var(--card-bg);
  border-radius: 50%;
  cursor: pointer;
  box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.range-labels {
  display: flex;
  justify-content: space-between;
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: var(--space-xs);
}

/* Input with unit suffix */
.input-with-unit {
  position: relative;
}

.input-with-unit input {
  padding-right: 60px;
}

.input-with-unit .unit {
  position: absolute;
  right: var(--space-md);
  top: 50%;
  transform: translateY(-50%);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
  pointer-events: none;
}

/* Toggle Buttons */
.toggle-group {
  display: flex;
  gap: 0;
  border: var(--border-w) solid var(--border-strong);
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--bg);
}

.toggle-group .toggle-btn {
  flex: 1;
  padding: var(--space-md);
  font-family: var(--font-body);
  font-weight: 600;
  font-size: 0.9rem;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--duration) var(--ease);
  text-align: center;
  min-height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.toggle-group .toggle-btn:not(:last-child) {
  border-right: var(--border-w) solid var(--border-strong);
}

.toggle-group .toggle-btn.active {
  background: var(--primary);
  color: white;
  box-shadow: inset 0 2px 4px rgba(0,0,0,0.1);
}

.toggle-group .toggle-btn:hover:not(.active) {
  background: var(--bg-alt);
}

/* ---------- Result Display ---------- */
.result-display {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border: var(--border-w) solid var(--text);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  text-align: center;
  color: white;
  box-shadow: var(--shadow-neo);
  margin-top: var(--space-lg);
}

.result-display .result-label {
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  opacity: 0.85;
  margin-bottom: var(--space-sm);
}

.result-display .result-value {
  font-family: var(--font-mono);
  font-size: clamp(2rem, 8vw, 3.2rem);
  font-weight: 700;
  line-height: 1.1;
  margin-bottom: var(--space-xs);
}

.result-display .result-unit {
  font-size: 1rem;
  font-weight: 500;
  opacity: 0.8;
}

.result-display .result-note {
  font-size: 0.85rem;
  opacity: 0.7;
  margin-top: var(--space-sm);
}

/* Multiple results */
.results-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-md);
  margin-top: var(--space-lg);
}

@media (min-width: 480px) {
  .results-grid { grid-template-columns: 1fr 1fr; }
}

.result-item {
  background: var(--bg);
  border: var(--border-w) solid var(--border-strong);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  text-align: center;
  box-shadow: var(--shadow);
}

.result-item .result-item-label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-sm);
}

.result-item .result-item-value {
  font-family: var(--font-mono);
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--text);
}

.result-item .result-item-unit {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: var(--space-xs);
}

/* Color-coded results */
.result-display.result-good { background: linear-gradient(135deg, var(--success), #047857); }
.result-display.result-warn { background: linear-gradient(135deg, var(--warning), #b45309); }
.result-display.result-bad  { background: linear-gradient(135deg, var(--danger), #b91c1c); }

/* ---------- Donut Chart ---------- */
.chart-container {
  display: flex;
  justify-content: center;
  align-items: center;
  padding: var(--space-lg) 0;
}

.donut-chart {
  position: relative;
  width: 200px;
  height: 200px;
}

.donut-chart canvas {
  width: 100%;
  height: 100%;
}

.donut-chart .chart-center {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  text-align: center;
}

.donut-chart .chart-center .chart-total {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 700;
}

.donut-chart .chart-center .chart-label {
  font-size: 0.75rem;
  color: var(--text-muted);
}

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

.chart-legend-item {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 0.85rem;
  font-weight: 500;
}

.chart-legend-item .swatch {
  width: 14px;
  height: 14px;
  border-radius: 4px;
  border: 1px solid rgba(0,0,0,0.1);
}

/* ---------- CTA / Affiliate ---------- */
.cta-box {
  background: var(--accent-light);
  border: var(--border-w) solid var(--accent);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  margin-top: var(--space-xl);
  display: flex;
  align-items: center;
  gap: var(--space-md);
  box-shadow: var(--shadow);
}

.cta-box .cta-icon {
  font-size: 1.8rem;
  flex-shrink: 0;
}

.cta-box .cta-content {
  flex: 1;
}

.cta-box .cta-content p {
  font-size: 0.9rem;
  margin-bottom: var(--space-sm);
}

.cta-box .cta-link {
  display: inline-block;
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--warning);
}

.cta-box .cta-link:hover {
  color: var(--text);
}

/* ---------- Article Content ---------- */
.article-content {
  background: var(--card-bg);
  border: var(--border-w) solid var(--border-strong);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  box-shadow: var(--shadow);
  margin-top: var(--space-xl);
}

.article-content h2 {
  font-size: 1.4rem;
  font-weight: 800;
  margin: var(--space-xl) 0 var(--space-md);
  color: var(--text);
}

.article-content h2:first-child {
  margin-top: 0;
}

.article-content h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin: var(--space-lg) 0 var(--space-sm);
}

.article-content p {
  margin-bottom: var(--space-md);
  color: var(--text-secondary);
  line-height: 1.7;
}

.article-content ul,
.article-content ol {
  margin-bottom: var(--space-md);
  padding-left: var(--space-lg);
  color: var(--text-secondary);
}

.article-content li {
  margin-bottom: var(--space-sm);
  line-height: 1.6;
}

.article-content strong {
  color: var(--text);
  font-weight: 600;
}

.article-content code {
  font-family: var(--font-mono);
  background: var(--bg);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.9em;
}

.article-content .formula-box {
  background: var(--bg);
  border: var(--border-w) solid var(--border);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  margin: var(--space-lg) 0;
  font-family: var(--font-mono);
  font-size: 1rem;
  text-align: center;
  font-weight: 600;
  color: var(--primary);
}

.article-content .tip-box {
  background: var(--success-light);
  border-left: 4px solid var(--success);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: var(--space-md) var(--space-lg);
  margin: var(--space-lg) 0;
}

.article-content .tip-box strong {
  color: var(--success);
}

.article-content .warning-box {
  background: var(--warning-light);
  border-left: 4px solid var(--warning);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: var(--space-md) var(--space-lg);
  margin: var(--space-lg) 0;
}

.article-content .warning-box strong {
  color: var(--warning);
}

/* ---------- Footer ---------- */
.site-footer {
  text-align: center;
  padding: var(--space-2xl) 0;
  color: var(--text-muted);
  font-size: 0.85rem;
  border-top: 1px solid var(--border);
  margin-top: var(--space-3xl);
}

.site-footer a {
  color: var(--text-secondary);
}

/* ---------- Homepage Grid ---------- */
.category-section {
  margin-bottom: var(--space-2xl);
}

.category-section h2 {
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--text);
  margin-bottom: var(--space-lg);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.category-section h2 .cat-icon {
  font-size: 1.4rem;
}

.calc-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-md);
}

@media (min-width: 480px) {
  .calc-grid { grid-template-columns: 1fr 1fr; }
}

@media (min-width: 768px) {
  .calc-grid { grid-template-columns: 1fr 1fr 1fr; }
}

.calc-grid-item {
  background: var(--card-bg);
  border: var(--border-w) solid var(--border-strong);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  box-shadow: var(--shadow-neo);
  transition: transform var(--duration) var(--ease), box-shadow var(--duration) var(--ease);
  text-decoration: none;
  color: inherit;
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.calc-grid-item:hover {
  transform: translate(-2px, -2px);
  box-shadow: 8px 8px 0px rgba(0,0,0,0.12);
  text-decoration: none;
}

.calc-grid-item .grid-icon {
  font-size: 1.8rem;
  margin-bottom: var(--space-xs);
}

.calc-grid-item h3 {
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.3;
}

.calc-grid-item p {
  font-size: 0.8rem;
  color: var(--text-secondary);
  line-height: 1.5;
  flex: 1;
}

.calc-grid-item .grid-tag {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--primary);
  background: var(--primary-light);
  padding: 2px 8px;
  border-radius: 4px;
  align-self: flex-start;
}

/* ---------- Breadcrumb ---------- */
.breadcrumb {
  display: flex;
  gap: var(--space-sm);
  align-items: center;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: var(--space-lg);
  flex-wrap: wrap;
}

.breadcrumb a {
  color: var(--text-secondary);
}

.breadcrumb .sep {
  color: var(--text-muted);
}

/* ---------- Ad Slots ---------- */

/* Base ad container */
.ad-slot {
  margin: var(--space-xl) 0;
  text-align: center;
  min-height: 50px;
  overflow: hidden;
}

.ad-slot ins {
  display: block;
}

/* Header banner — 728×90 leaderboard, responsive */
.ad-slot.ad-header {
  max-width: 728px;
  margin: var(--space-md) auto;
  min-height: 90px;
}

/* After-result rectangle — 336×280 or responsive */
.ad-slot.ad-after-result {
  margin: var(--space-xl) auto;
  max-width: 400px;
  min-height: 250px;
}

/* In-article native ad */
.ad-slot.ad-in-article {
  margin: var(--space-xl) 0;
  padding: var(--space-sm) 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

/* Sticky footer ad (mobile only) */
.ad-sticky-footer {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 999;
  background: var(--card-bg);
  border-top: var(--border-w) solid var(--border-strong);
  box-shadow: 0 -2px 10px rgba(0,0,0,0.1);
  text-align: center;
  padding: var(--space-sm);
  transform: translateY(100%);
  transition: transform 0.3s var(--ease);
  display: none;
}

@media (max-width: 768px) {
  .ad-sticky-footer { display: block; }
}

.ad-sticky-footer.ad-sticky-visible {
  transform: translateY(0);
}

.ad-sticky-footer .ad-sticky-close {
  position: absolute;
  top: -24px;
  right: 8px;
  width: 24px;
  height: 24px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-bottom: none;
  border-radius: 4px 4px 0 0;
  font-size: 14px;
  line-height: 24px;
  cursor: pointer;
  color: var(--text-muted);
  text-align: center;
}

/* Dev-mode placeholder labels */
.ad-placeholder-label {
  background: var(--bg-alt);
  border: 2px dashed var(--border-strong);
  border-radius: var(--radius-sm);
  padding: var(--space-md) var(--space-lg);
  color: var(--text-muted);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

/* Add bottom padding to body when sticky footer is visible (mobile) */
@media (max-width: 768px) {
  body.has-sticky-ad {
    padding-bottom: 70px;
  }
}

/* Legacy placeholder (for backwards compat during migration) */
.ad-placeholder {
  background: var(--bg-alt);
  border: 2px dashed var(--border-strong);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  text-align: center;
  color: var(--text-muted);
  font-size: 0.8rem;
  margin: var(--space-lg) 0;
}

/* ---------- Utility ---------- */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  border: 0;
}

.text-center { text-align: center; }
.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); }
.mb-md { margin-bottom: var(--space-md); }

/* ---------- Responsive polish ---------- */
@media (max-width: 480px) {
  .calc-card {
    padding: var(--space-lg);
  }

  .result-display {
    padding: var(--space-lg);
  }

  .article-content {
    padding: var(--space-lg);
  }

  .site-nav {
    display: none;
  }
}

@media (min-width: 768px) {
  .calc-card {
    padding: var(--space-2xl);
  }
}

/* ---------- Print styles ---------- */
@media print {
  .site-header,
  .site-footer,
  .ad-placeholder,
  .cta-box { display: none; }

  .calc-card {
    box-shadow: none;
    border: 1px solid #ccc;
  }

  body { background: white; }
}