:root {
  --brand-primary: #0b5d8d;
  --brand-primary-strong: #08456d;
  --brand-secondary: #0f7c84;
  --brand-surface: #f4f8fb;
  --brand-surface-soft: #eaf1f7;
  --brand-card: #ffffff;
  --brand-border: #d5e2ec;
  --brand-ink: #102235;
  --brand-muted: #556476;
  --brand-success: #0c8f61;
  --brand-danger: #b42318;
  /* Research chart palette */
  --chart-primary: #0b5d8d;
  --chart-secondary: #0f7c84;
  --chart-grid: #cfdce8;
  --chart-text: #102235;
  --chart-tick: #556476;
  --chart-band-c2: #d8e6f3;
  --chart-band-c1: #e3eef7;
  --chart-band-b2: #e8f0f8;
  --chart-band-b1: #edf3f9;
  --chart-band-a2: #f2f6fb;
  --chart-band-a1: #f7f9fc;
  --radius-md: 0.85rem;
  --radius-lg: 1rem;
  --shadow-sm: 0 8px 24px rgba(16, 34, 53, 0.07);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: #ffffff;
  color: var(--brand-ink);
  font-family: 'IBM Plex Sans', sans-serif;
  line-height: 1.65;
}

a {
  color: var(--brand-primary);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.14em;
}

a:hover {
  color: var(--brand-primary-strong);
}

h1,
h2,
h3,
h4 {
  margin-top: 0;
  color: var(--brand-ink);
  font-family: 'Source Serif 4', serif;
  line-height: 1.25;
}

h1 {
  font-size: clamp(2rem, 4vw, 2.65rem);
  margin-bottom: 0.5rem;
}

h2,
.markdown h2,
.prose h2,
article h2 {
  font-size: clamp(1.55rem, 2.4vw, 1.9rem);
  color: var(--brand-primary);
  margin-bottom: 0.95rem;
}

h3,
.research-post h3,
.card h3,
.col-md-8 h3,
[class*="research"] h3,
#textanalyser-powered-by-cefrai {
  font-size: 1.28rem;
  margin-bottom: 0.8rem;
}

h4 {
  font-size: 1.08rem;
  margin-bottom: 0.7rem;
  font-family: 'IBM Plex Sans', sans-serif;
  font-weight: 700;
  color: var(--brand-muted);
}

p {
  margin-bottom: 1rem;
  color: var(--brand-ink);
}

p.secondary,
.secondary {
  color: var(--brand-muted) !important;
}

ul,
ol {
  margin-bottom: 1rem;
  padding-left: 1.4rem;
}

li {
  margin-bottom: 0.45rem;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  backdrop-filter: blur(12px);
  background: rgba(255, 255, 255, 0.92);
  border-bottom: 1px solid var(--brand-border);
}

.site-brand-subtitle {
  margin-top: 0.3rem;
  font-size: 0.88rem;
  letter-spacing: 0.02em;
  color: var(--brand-muted);
}

.site-logo {
  height: 2.5rem;
  width: auto;
}

.site-nav-link {
  color: var(--brand-muted);
  font-weight: 600;
  border-radius: 0.55rem;
  transition: background-color 0.2s ease, color 0.2s ease;
}

.site-nav-link:hover {
  color: var(--brand-primary-strong);
  background-color: var(--brand-surface-soft);
}

.site-nav-icon {
  width: 1rem;
  height: 1rem;
}

.site-footer {
  color: var(--brand-muted);
  font-size: 0.9rem;
}

.home-kicker {
  display: inline-block;
  margin-bottom: 0.4rem;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--brand-primary);
}

.home-lead {
  max-width: 56rem;
}

.home-cta-row .btn {
  min-width: 12.6rem;
}

.triangulation-diagram {
  width: 100%;
  border: 1px solid var(--brand-border);
  border-radius: var(--radius-lg);
  background: #fbfdff;
  padding: 0.8rem;
}

.triangulation-diagram svg {
  width: 100%;
  height: auto;
  display: block;
}

.tri-node {
  fill: #ffffff;
  stroke: var(--brand-border);
  stroke-width: 2;
}

.tri-node-title {
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 25px;
  font-weight: 700;
  fill: var(--brand-ink);
}

.tri-node-body {
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 19px;
  fill: var(--brand-muted);
}

.tri-core {
  fill: #f4f9fd;
  stroke: var(--brand-primary);
  stroke-width: 3;
}

.tri-core-title {
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 24px;
  font-weight: 700;
  fill: var(--brand-primary-strong);
}

.tri-core-sub {
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 20px;
  font-weight: 600;
  fill: var(--brand-muted);
}

.card {
  border: 1px solid var(--brand-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  background-color: var(--brand-card);
}

.site-callout {
  border: 1px solid rgba(11, 93, 141, 0.18);
  border-left: 4px solid var(--brand-primary);
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.92);
  padding: 1rem 1.1rem;
  color: var(--brand-muted);
}

.site-callout p:last-child {
  margin-bottom: 0;
}

.badge {
  border-radius: 999px;
  padding: 0.35rem 0.7rem;
  font-family: 'IBM Plex Sans', sans-serif;
  font-size: 0.73rem;
  font-weight: 600;
  border: 1px solid transparent;
}

.bg-emerald-600 {
  background-color: var(--brand-primary) !important;
}

.bg-light {
  background-color: var(--brand-surface-soft) !important;
}

.bg-slate-50 {
  background-color: var(--brand-surface-soft);
}

.text-emerald-600 {
  color: var(--brand-success);
}

.text-slate-600 {
  color: var(--brand-muted);
}

.text-slate-500 {
  color: #6f7f93;
}

.text-red-600 {
  color: var(--brand-danger);
}

.btn {
  border-radius: var(--radius-md);
  font-weight: 600;
  border: 1px solid transparent;
  transition: transform 0.15s ease, background-color 0.2s ease, color 0.2s ease;
  padding: 0.56rem 0.9rem;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn:focus {
  box-shadow: 0 0 0 0.2rem rgba(11, 93, 141, 0.2) !important;
}

.btn-engine {
  background-color: var(--brand-primary);
  border-color: var(--brand-primary);
  color: #fff;
}

.btn-engine:hover,
.btn-engine:focus {
  background-color: var(--brand-primary-strong);
  border-color: var(--brand-primary-strong);
  color: #fff;
}

.btn-secondary {
  background-color: #e3eaf0;
  border-color: #d2dce6;
  color: var(--brand-ink);
}

.btn-secondary:hover,
.btn-secondary:focus {
  background-color: #d5e0ea;
  border-color: #c4d1dc;
  color: var(--brand-ink);
}

.btn:disabled {
  cursor: not-allowed;
  opacity: 0.72;
  transform: none;
}

.analyzer-textarea {
  border: 1px solid var(--brand-border);
  border-radius: var(--radius-md);
  padding: 0.95rem;
  min-height: 11rem;
  resize: vertical;
  color: var(--brand-ink);
  background-color: #fff;
}

.analyzer-textarea:focus {
  border-color: var(--brand-primary);
  box-shadow: 0 0 0 0.2rem rgba(11, 93, 141, 0.14);
}

.message-container {
  min-height: 1.5rem;
}

#textError {
  color: var(--brand-danger);
  font-weight: 500;
}

.gse-score,
.cefr-score {
  font-family: 'Source Serif 4', serif;
  font-size: clamp(2rem, 4vw, 2.8rem);
  line-height: 1.1;
}

.gse-score {
  color: var(--brand-primary);
}

.cefr-score {
  color: var(--brand-secondary);
}

table {
  width: 100%;
  border-collapse: collapse;
}

th,
td {
  padding: 0.66rem 0.45rem;
  border-bottom: 1px solid var(--brand-border);
  vertical-align: top;
}

th {
  font-weight: 700;
  color: var(--brand-ink);
}

pre,
code {
  background-color: #edf3f8;
  border-radius: 0.35rem;
}

code {
  padding: 0.15rem 0.35rem;
}

pre {
  padding: 0.9rem;
  overflow-x: auto;
}

blockquote {
  margin: 1.2rem 0;
  padding: 1rem 1.05rem;
  border-left: 4px solid var(--brand-primary);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  background: #f3f8fc;
}

.ruler-container,
.ruler-container svg,
.research-post svg,
.research-post img[src$=".svg"] {
  width: 100% !important;
  max-width: 100%;
  height: auto !important;
}

.form-check {
  border: 1px solid var(--brand-border);
  border-radius: 0.65rem;
  background: #fbfdff;
  padding: 0.6rem 0.65rem 0.55rem 2.15rem;
}

.form-check-input {
  margin-top: 0.28rem;
}

.form-check-input:checked {
  background-color: var(--brand-primary);
  border-color: var(--brand-primary);
}

.feedback-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 1.2rem;
}

.question-form .form-check + .form-check {
  margin-top: 0.5rem;
}

.hidden {
  display: none !important;
}

.animate-prepare {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.45s ease, transform 0.45s ease;
  transition-delay: var(--anim-delay, 0ms);
  will-change: opacity, transform;
}

.animate-start,
.animation-complete {
  opacity: 1;
  transform: translateY(0);
}

.is-spinning {
  animation: spin 1s linear infinite;
}

@keyframes spin {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}

.rounded-lg {
  border-radius: var(--radius-lg) !important;
}

.shadow-sm {
  box-shadow: var(--shadow-sm) !important;
}

.gap-2 {
  gap: 0.5rem;
}

.gap-4 {
  gap: 1rem;
}

@media (max-width: 991px) {
  .site-header {
    position: static;
  }

  .site-brand-subtitle {
    font-size: 0.82rem;
  }

  .site-nav {
    overflow-x: auto;
    padding-bottom: 0.15rem;
  }

  .site-nav-link {
    white-space: nowrap;
  }
}

@media (max-width: 767px) {
  .container-fluid {
    padding-left: 1rem !important;
    padding-right: 1rem !important;
  }

  .btn-container {
    flex-direction: column;
  }

  .btn-container .btn {
    width: 100% !important;
  }

  h1 {
    font-size: 2rem;
  }

  .triangulation-diagram {
    padding: 0.45rem;
    overflow-x: auto;
  }

  .triangulation-diagram svg {
    min-width: 680px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}