/* ==========================================================================
   gratisRekenmachine.com — De Stijl / Mondrian Dutch Grid System
   Enhanced with UI/UX Pro Max Intelligence (v2.13.0)
   ========================================================================== */

:root {
  --ink: #111111;
  --paper: #ffffff;
  --panel: #f4f4f0;
  --red: #d5121f;
  --blue: #134ea8;
  --yellow: #f4c300;
  --border-width: 3px;
  --border: 3px solid #111111;
  --font-heading: 'Space Grotesk', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'Space Mono', 'Courier New', Courier, monospace;
}

/* Reset & Box Sizing */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  border-radius: 0 !important; /* Enforce zero border-radius everywhere */
  box-shadow: none !important; /* Zero drop shadows */
}

html {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.5;
  color: var(--ink);
  background-color: var(--paper);
  -webkit-text-size-adjust: 100%;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background-color: var(--paper);
}

/* UI/UX Pro Max Rule 45: Accessibility Skip Link */
.skip-link {
  position: absolute;
  top: -100px;
  left: 1rem;
  background-color: var(--yellow);
  color: var(--ink);
  padding: 0.75rem 1.25rem;
  font-family: var(--font-heading);
  font-weight: 700;
  text-transform: uppercase;
  border: 3px solid var(--ink);
  z-index: 1000;
  text-decoration: none;
}
.skip-link:focus {
  top: 1rem;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  color: var(--ink);
  line-height: 1.15;
  text-transform: uppercase;
  letter-spacing: -0.02em;
}

h1 { font-size: clamp(2rem, 4vw, 3.2rem); margin-bottom: 1rem; }
h2 { font-size: clamp(1.5rem, 3vw, 2.2rem); margin-bottom: 1rem; }
h3 { font-size: clamp(1.2rem, 2vw, 1.5rem); margin-bottom: 0.75rem; }

p {
  margin-bottom: 1rem;
  color: #222222;
}

a {
  color: var(--blue);
  text-decoration: none;
  font-weight: 600;
}

a:hover {
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 4px;
}

/* Container */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

/* ==========================================================================
   Header & Top Mondrian Bar
   ========================================================================== */
.top-stripe {
  display: flex;
  height: 8px;
  width: 100%;
}

.top-stripe .stripe-red { flex: 3; background-color: var(--red); }
.top-stripe .stripe-yellow { flex: 1.5; background-color: var(--yellow); }
.top-stripe .stripe-blue { flex: 2; background-color: var(--blue); }
.top-stripe .stripe-ink { flex: 1; background-color: var(--ink); }

.site-header {
  background-color: var(--paper);
  border-bottom: var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none !important;
}

.logo-mark {
  position: relative;
  width: 34px;
  height: 34px;
}

.logo-mark .block-red {
  position: absolute;
  top: 0;
  left: 0;
  width: 24px;
  height: 24px;
  background-color: var(--red);
  border: 2px solid var(--ink);
}

.logo-mark .block-yellow {
  position: absolute;
  bottom: 0;
  right: 0;
  width: 18px;
  height: 18px;
  background-color: var(--yellow);
  border: 2px solid var(--ink);
}

.brand-text {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.35rem;
  color: var(--ink);
  letter-spacing: -0.03em;
}

.brand-text span {
  color: var(--red);
}

.main-nav {
  display: flex;
  gap: 1.25rem;
  list-style: none;
  align-items: center;
}

.nav-link {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--ink);
  text-transform: uppercase;
  padding: 0.25rem 0;
}

.nav-link:hover, .nav-link.active {
  color: var(--blue);
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 4px;
}

/* ==========================================================================
   Hero Section
   ========================================================================== */
.hero {
  background-color: var(--panel);
  border-bottom: var(--border);
  padding: 3rem 0;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr 420px;
  gap: 2.5rem;
  align-items: start;
}

@media (max-width: 900px) {
  .hero-grid {
    grid-template-columns: 1fr;
  }
}

.eyebrow {
  display: inline-block;
  background-color: var(--yellow);
  color: var(--ink);
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.85rem;
  text-transform: uppercase;
  padding: 0.35rem 0.75rem;
  border: 2px solid var(--ink);
  margin-bottom: 1rem;
}

.hero-lead {
  font-size: 1.15rem;
  color: #333333;
  margin-bottom: 1.5rem;
  line-height: 1.6;
}

.hero-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.badge {
  background-color: var(--paper);
  border: 2px solid var(--ink);
  padding: 0.4rem 0.8rem;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.8rem;
  text-transform: uppercase;
}

.home-reveal {
  opacity: 0;
  transform: translateY(12px);
  animation: revealFade 350ms cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

.home-reveal-1 { animation-delay: 0ms; }
.home-reveal-2 { animation-delay: 80ms; }
.home-reveal-3 { animation-delay: 160ms; }

@keyframes revealFade {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ==========================================================================
   Calculator Component (UI/UX Pro Max Optimized Buttons & Touch Targets)
   ========================================================================== */
.calc {
  background-color: var(--ink);
  border: var(--border);
  padding: 1rem;
  width: 100%;
}

.calc-display {
  background-color: var(--ink);
  border: 2px solid #333333;
  color: var(--paper);
  padding: 1rem;
  text-align: right;
  margin-bottom: 1rem;
  min-height: 90px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.calc-history {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: #888888;
  min-height: 1.25rem;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.calc-value {
  font-family: var(--font-mono);
  font-size: 2.2rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  color: #ffffff;
}

.calc-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 2px;
  background-color: #333333;
  border: 2px solid #333333;
}

.calc-grid-scientific {
  grid-template-columns: repeat(5, 1fr);
}

/* UI/UX Pro Max Touch Target & Hierarchy Optimization (Rules 22, 23, 66) */
.calc-btn {
  background-color: var(--panel);
  color: var(--ink);
  border: none;
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  padding: 1rem 0.5rem;
  min-height: 52px; /* Minimum 48px+ touch target size */
  min-width: 48px;
  cursor: pointer;
  user-select: none;
  transition: background-color 120ms ease;
  display: flex;
  align-items: center;
  justify-content: center;
}

.calc-btn:hover { background-color: #e2e2dc; }
.calc-btn:active { background-color: #cccccc; }

.calc-btn.op { background-color: var(--blue); color: var(--paper); }
.calc-btn.op:hover { background-color: #0f3f88; }
.calc-btn.op:active { background-color: #0b2f66; }

.calc-btn.fn { background-color: #e5e5de; color: var(--ink); font-size: 1rem; }

.calc-btn.eq { background-color: var(--red); color: var(--paper); font-size: 1.5rem; }
.calc-btn.eq:hover { background-color: #b50e19; }
.calc-btn.eq:active { background-color: #920b13; }

.calc-btn.span-2 { grid-column: span 2; }
.calc-btn.height-2 { grid-row: span 2; }

/* ==========================================================================
   Tool Grid
   ========================================================================== */
.tool-section {
  padding: 4rem 0;
  background-color: var(--paper);
}

.section-title {
  margin-bottom: 2rem;
  position: relative;
  display: inline-block;
}

.section-title::after {
  content: '';
  display: block;
  width: 100%;
  height: 4px;
  background-color: var(--red);
  margin-top: 0.5rem;
}

.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.75rem;
}

.tool-card {
  background-color: var(--paper);
  border: var(--border);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  text-decoration: none !important;
  transition: transform 150ms ease, border-color 150ms ease;
  position: relative;
}

.tool-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 6px;
  background-color: var(--ink);
}

.tool-card.card-red::before { background-color: var(--red); }
.tool-card.card-blue::before { background-color: var(--blue); }
.tool-card.card-yellow::before { background-color: var(--yellow); }

.tool-card:hover {
  border-color: var(--blue);
  transform: translateY(-4px);
}

.tool-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1rem;
}

.tool-icon {
  width: 44px;
  height: 44px;
  background-color: var(--panel);
  border: 2px solid var(--ink);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.tool-card h3 {
  font-size: 1.15rem;
  color: var(--ink);
  margin-bottom: 0;
}

.tool-desc {
  font-size: 0.95rem;
  color: #444444;
  margin-bottom: 1.25rem;
}

.tool-action {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.85rem;
  text-transform: uppercase;
  color: var(--blue);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.tool-card:hover .tool-action { color: var(--red); }

/* ==========================================================================
   Tool Page Layout & Forms
   ========================================================================== */
.page-container {
  padding: 3rem 0;
}

.calculator-wrapper {
  display: grid;
  grid-template-columns: 1fr 380px;
  gap: 2.5rem;
  align-items: start;
  margin-bottom: 3.5rem;
}

@media (max-width: 900px) {
  .calculator-wrapper {
    grid-template-columns: 1fr;
  }
}

.calc-panel {
  background-color: var(--panel);
  border: var(--border);
  padding: 1.75rem;
}

.calc-form-group {
  margin-bottom: 1.25rem;
}

.calc-label {
  display: block;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.9rem;
  text-transform: uppercase;
  margin-bottom: 0.5rem;
  color: var(--ink);
}

.calc-input, .calc-select, .calc-textarea {
  width: 100%;
  padding: 0.85rem 1rem;
  font-family: var(--font-body);
  font-size: 1rem;
  font-weight: 500;
  background-color: var(--paper);
  border: 2px solid var(--ink);
  color: var(--ink);
  outline: none;
  min-height: 48px; /* Touch friendly input height */
}

.calc-textarea {
  min-height: 120px;
  resize: vertical;
}

.calc-input:focus, .calc-select:focus, .calc-textarea:focus {
  border-color: var(--blue);
  background-color: #ffffff;
}

.calc-btn-block {
  width: 100%;
  padding: 1rem;
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 700;
  text-transform: uppercase;
  background-color: var(--red);
  color: var(--paper);
  border: 2px solid var(--ink);
  min-height: 52px;
  cursor: pointer;
}

.calc-btn-block:hover { background-color: #b50e19; }
.calc-btn-block:active { background-color: #920b13; }

/* Result Box Flash Animation */
.result-box {
  background-color: var(--paper);
  border: 3px solid var(--ink);
  padding: 1.5rem;
  margin-top: 1.5rem;
  transition: border-color 300ms ease, background-color 300ms ease;
}

.result-box.flash-result {
  border-color: var(--yellow) !important;
  background-color: #fffde6;
}

.result-label {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.85rem;
  text-transform: uppercase;
  color: #666666;
  margin-bottom: 0.35rem;
}

.result-value {
  font-family: var(--font-mono);
  font-size: 2.2rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--blue);
  word-break: break-all;
}

.result-details {
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid #e0e0e0;
  font-size: 0.95rem;
  color: #333333;
}

.result-detail-row {
  display: flex;
  justify-content: space-between;
  margin-bottom: 0.35rem;
}

.result-detail-row span:last-child {
  font-family: var(--font-mono);
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

/* Form Alert Messages */
.form-alert {
  padding: 1rem 1.25rem;
  border: 2px solid var(--ink);
  margin-bottom: 1.5rem;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.95rem;
}

.form-alert-success {
  background-color: var(--yellow);
  color: var(--ink);
}

.form-alert-error {
  background-color: var(--red);
  color: var(--paper);
}

.hp-field {
  display: none !important;
}

/* ==========================================================================
   Worked Example & FAQs & Content Boxes
   ========================================================================== */
.content-box {
  background-color: var(--paper);
  border: var(--border);
  padding: 2rem;
  margin-bottom: 2.5rem;
}

.policy-content h2 {
  font-size: 1.5rem;
  margin-top: 1.75rem;
  margin-bottom: 0.75rem;
  border-bottom: 2px solid var(--yellow);
  padding-bottom: 0.35rem;
  display: inline-block;
}

.policy-content h3 {
  font-size: 1.2rem;
  margin-top: 1.25rem;
  margin-bottom: 0.5rem;
}

.policy-content ul, .policy-content ol {
  margin-bottom: 1.25rem;
  padding-left: 1.5rem;
}

.policy-content li {
  margin-bottom: 0.5rem;
  line-height: 1.6;
}

.worked-example {
  background-color: #fdfdfa;
  border-left: 6px solid var(--blue);
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0;
  border: 1px solid #e5e5e0;
  border-left: 6px solid var(--blue);
}

.worked-example h4 {
  font-size: 1rem;
  color: var(--blue);
  margin-bottom: 0.5rem;
}

.faq-section {
  margin-top: 3rem;
}

.faq-list {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.faq-item {
  background-color: var(--panel);
  border: 2px solid var(--ink);
  padding: 1.25rem;
}

.faq-dt {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--ink);
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.faq-dt::before {
  content: 'Q:';
  color: var(--red);
}

.faq-dd {
  font-size: 0.95rem;
  color: #333333;
  line-height: 1.6;
}

.related-tools {
  background-color: var(--panel);
  border: var(--border);
  padding: 1.75rem;
  margin-top: 3rem;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.25rem;
  margin-top: 1rem;
}

.calc-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 1.5rem;
  font-size: 0.9rem;
}

.calc-table th {
  background-color: var(--ink);
  color: var(--paper);
  font-family: var(--font-heading);
  font-weight: 700;
  text-transform: uppercase;
  padding: 0.75rem;
  text-align: left;
}

.calc-table td {
  padding: 0.65rem 0.75rem;
  border-bottom: 1px solid #dddddd;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
}

.calc-table tr:nth-child(even) {
  background-color: var(--panel);
}

.graph-container {
  background-color: #ffffff;
  border: 3px solid var(--ink);
  position: relative;
  width: 100%;
  aspect-ratio: 4 / 3;
}

#graphCanvas {
  width: 100%;
  height: 100%;
  display: block;
}

/* ==========================================================================
   Cookie Consent Banner Bar
   ========================================================================== */
.cookie-banner {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  background-color: var(--yellow);
  border-top: var(--border);
  color: var(--ink);
  padding: 1rem 0;
  z-index: 1000;
  display: none;
}

.cookie-banner-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.cookie-banner-text {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--ink);
  flex: 1;
  min-width: 280px;
}

.cookie-banner-text a {
  color: var(--ink);
  text-decoration: underline;
  font-weight: 700;
}

.cookie-banner-btn {
  background-color: var(--ink);
  color: var(--paper);
  border: 2px solid var(--ink);
  padding: 0.6rem 1.25rem;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.9rem;
  text-transform: uppercase;
  cursor: pointer;
  min-height: 48px;
}

.cookie-banner-btn:hover {
  background-color: var(--red);
  color: var(--paper);
}

/* ==========================================================================
   Footer Component
   ========================================================================== */
.site-footer {
  background-color: var(--ink);
  color: var(--paper);
  border-top: var(--border);
  margin-top: auto;
  padding: 3.5rem 0 2rem;
}

.footer-stripe {
  display: flex;
  height: 6px;
  width: 100%;
  margin-bottom: 2.5rem;
}

.footer-stripe .stripe-red { flex: 1; background-color: var(--red); }
.footer-stripe .stripe-yellow { flex: 1; background-color: var(--yellow); }
.footer-stripe .stripe-blue { flex: 1; background-color: var(--blue); }

.footer-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 2rem;
  margin-bottom: 3rem;
}

@media (max-width: 950px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 550px) {
  .footer-grid {
    grid-template-columns: 1fr;
  }
}

.footer-col h4 {
  color: var(--paper);
  font-size: 1.05rem;
  margin-bottom: 1rem;
  border-bottom: 2px solid var(--yellow);
  padding-bottom: 0.35rem;
  display: inline-block;
}

.footer-col p {
  color: #cccccc;
  font-size: 0.9rem;
  line-height: 1.6;
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: 0.5rem;
}

.footer-links a {
  color: #dddddd;
  font-size: 0.9rem;
  font-weight: 500;
}

.footer-links a:hover {
  color: var(--yellow);
}

.footer-bottom {
  border-top: 1px solid #333333;
  padding-top: 1.5rem;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  font-size: 0.85rem;
  color: #999999;
}

/* UI/UX Pro Max Rule 28 & 102: Accessibility Focus Indicator Rings */
:focus-visible {
  outline: 3px solid var(--yellow) !important;
  outline-offset: 3px !important;
}

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