/* EpiTools Design System
   Professional medical/scientific design
   Colors: Navy, Blue, Light backgrounds, White cards
   Typography: Inter for UI, Georgia for formulas */

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

:root {
  --navy: #1a365d;
  --blue: #2b6cb0;
  --blue-light: #3182ce;
  --blue-pale: #ebf4ff;
  --gray-50: #f7fafc;
  --gray-100: #edf2f7;
  --gray-200: #e2e8f0;
  --gray-300: #cbd5e0;
  --gray-400: #a0aec0;
  --gray-500: #718096;
  --gray-600: #4a5568;
  --gray-700: #2d3748;
  --gray-800: #1a202c;
  --white: #ffffff;
  --green: #38a169;
  --green-light: #f0fff4;
  --red: #e53e3e;
  --red-light: #fff5f5;
  --orange: #dd6b20;
  --orange-light: #fffaf0;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.1);
  --radius: 8px;
  --radius-lg: 12px;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  color: var(--gray-700);
  background: var(--gray-50);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--blue);
  text-decoration: none;
}
a:hover {
  color: var(--blue-light);
  text-decoration: underline;
}

/* === Typography === */
h1, h2, h3, h4 {
  color: var(--navy);
  font-weight: 700;
  line-height: 1.3;
}

h1 { font-size: 2rem; }
h2 { font-size: 1.5rem; }
h3 { font-size: 1.25rem; }
h4 { font-size: 1.1rem; }

/* === Layout === */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.container-narrow {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* === Header === */
.site-header {
  background: var(--navy);
  color: var(--white);
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-md);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.site-logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--white);
  font-size: 1.4rem;
  font-weight: 800;
  letter-spacing: -0.5px;
}
.site-logo:hover {
  color: var(--white);
  text-decoration: none;
}

.site-logo svg {
  width: 28px;
  height: 28px;
}

.header-controls {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.lang-toggle {
  background: rgba(255,255,255,0.15);
  border: 1px solid rgba(255,255,255,0.3);
  color: var(--white);
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 0.85rem;
  font-weight: 600;
  transition: background 0.2s;
}
.lang-toggle:hover {
  background: rgba(255,255,255,0.25);
}

.header-nav {
  display: flex;
  gap: 0.25rem;
  flex-wrap: wrap;
}

.header-nav a {
  color: rgba(255,255,255,0.85);
  padding: 0.35rem 0.6rem;
  border-radius: var(--radius);
  font-size: 0.8rem;
  font-weight: 500;
  transition: background 0.2s, color 0.2s;
  white-space: nowrap;
}
.header-nav a:hover,
.header-nav a.active {
  background: rgba(255,255,255,0.15);
  color: var(--white);
  text-decoration: none;
}

/* === Hero === */
.hero {
  background: linear-gradient(135deg, var(--navy) 0%, var(--blue) 100%);
  color: var(--white);
  padding: 3rem 0;
  text-align: center;
}

.hero h1 {
  color: var(--white);
  font-size: 2.5rem;
  margin-bottom: 0.75rem;
}

.hero .subtitle {
  font-size: 1.15rem;
  opacity: 0.9;
  max-width: 600px;
  margin: 0 auto 0.5rem;
}

.hero .credentials {
  font-size: 0.9rem;
  opacity: 0.75;
  margin-top: 0.75rem;
}

/* === Card Grid === */
.calc-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
  padding: 2rem 0;
}

.calc-card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  transition: box-shadow 0.2s, transform 0.15s;
  display: flex;
  flex-direction: column;
}
.calc-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

.calc-card-icon {
  width: 48px;
  height: 48px;
  background: var(--blue-pale);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1rem;
  color: var(--blue);
  font-size: 1.4rem;
}

.calc-card h3 {
  margin-bottom: 0.5rem;
}

.calc-card p {
  color: var(--gray-500);
  font-size: 0.9rem;
  flex: 1;
  margin-bottom: 1rem;
}

.calc-card .card-link {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  color: var(--blue);
  font-weight: 600;
  font-size: 0.9rem;
}
.calc-card .card-link:hover {
  text-decoration: none;
  gap: 0.5rem;
}

/* === Calculator Pages === */
.page-header {
  background: linear-gradient(135deg, var(--navy) 0%, var(--blue) 100%);
  color: var(--white);
  padding: 2rem 0;
}

.page-header h1 {
  color: var(--white);
  font-size: 1.8rem;
  margin-bottom: 0.35rem;
}

.page-header .page-desc {
  opacity: 0.85;
  font-size: 1rem;
}

.breadcrumb {
  font-size: 0.85rem;
  margin-bottom: 0.75rem;
  opacity: 0.8;
}
.breadcrumb a {
  color: rgba(255,255,255,0.8);
}
.breadcrumb a:hover {
  color: var(--white);
}

/* === Form Elements === */
.calc-section {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin: 1.5rem 0;
  box-shadow: var(--shadow-sm);
}

.calc-section h2 {
  margin-bottom: 1.25rem;
  padding-bottom: 0.75rem;
  border-bottom: 2px solid var(--gray-100);
}

.form-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  margin-bottom: 1rem;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.form-group label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--gray-600);
}

.form-group .hint {
  font-size: 0.75rem;
  color: var(--gray-400);
}

input[type="number"],
input[type="text"],
select,
textarea {
  padding: 0.6rem 0.75rem;
  border: 1.5px solid var(--gray-300);
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-family: inherit;
  color: var(--gray-700);
  background: var(--white);
  transition: border-color 0.2s, box-shadow 0.2s;
  width: 100%;
}

input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: var(--blue);
  box-shadow: 0 0 0 3px rgba(43, 108, 176, 0.15);
}

input[type="number"] {
  -moz-appearance: textfield;
}
input[type="number"]::-webkit-inner-spin-button,
input[type="number"]::-webkit-outer-spin-button {
  opacity: 1;
}

/* Radio / toggle groups */
.radio-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.radio-group label {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  font-weight: 500;
  cursor: pointer;
  padding: 0.4rem 0.75rem;
  border: 1.5px solid var(--gray-300);
  border-radius: var(--radius);
  font-size: 0.85rem;
  transition: all 0.15s;
}

.radio-group input[type="radio"] {
  width: auto;
  margin: 0;
}

.radio-group label:has(input:checked) {
  border-color: var(--blue);
  background: var(--blue-pale);
  color: var(--blue);
}

/* === Buttons === */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.65rem 1.5rem;
  font-size: 0.95rem;
  font-weight: 600;
  font-family: inherit;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  transition: background 0.2s, transform 0.1s;
}
.btn:active {
  transform: scale(0.98);
}

.btn-primary {
  background: var(--blue);
  color: var(--white);
}
.btn-primary:hover {
  background: var(--navy);
}

.btn-secondary {
  background: var(--gray-100);
  color: var(--gray-700);
  border: 1.5px solid var(--gray-300);
}
.btn-secondary:hover {
  background: var(--gray-200);
}

.btn-group {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}

/* === Results === */
.results-panel {
  background: var(--gray-50);
  border: 2px solid var(--blue-pale);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  margin-top: 1.5rem;
  display: none;
}

.results-panel.visible {
  display: block;
}

.result-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: 0.6rem 0;
  border-bottom: 1px solid var(--gray-200);
}

.result-row:last-child {
  border-bottom: none;
}

.result-label {
  font-size: 0.9rem;
  color: var(--gray-600);
  font-weight: 500;
}

.result-value {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--navy);
  font-family: 'Georgia', serif;
}

.result-value .ci {
  font-size: 0.85rem;
  color: var(--gray-500);
  font-weight: 400;
}

.result-highlight {
  background: var(--blue-pale);
  border-radius: var(--radius);
  padding: 1rem;
  text-align: center;
  margin-bottom: 1rem;
}

.result-highlight .big-number {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--navy);
  font-family: 'Georgia', serif;
}

.result-highlight .big-label {
  font-size: 0.85rem;
  color: var(--gray-500);
  margin-top: 0.25rem;
}

/* === Formula Display === */
.formula-box {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-left: 4px solid var(--blue);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 1.25rem;
  margin: 1rem 0;
  font-family: 'Georgia', 'Times New Roman', serif;
  font-size: 1.05rem;
  line-height: 1.8;
  overflow-x: auto;
}

.formula-box .formula-title {
  font-family: 'Inter', sans-serif;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--blue);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 0.5rem;
}

.formula-box .formula-math {
  color: var(--gray-800);
}

.formula-box .step {
  padding: 0.25rem 0;
  color: var(--gray-600);
  font-size: 0.95rem;
}

.formula-box .step-result {
  color: var(--navy);
  font-weight: 700;
}

/* === 2x2 Table === */
.contingency-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.9rem;
}

.contingency-table th,
.contingency-table td {
  border: 1px solid var(--gray-300);
  padding: 0.5rem 0.75rem;
  text-align: center;
}

.contingency-table th {
  background: var(--navy);
  color: var(--white);
  font-weight: 600;
  font-size: 0.8rem;
}

.contingency-table td input {
  width: 80px;
  text-align: center;
  margin: 0 auto;
}

.contingency-table td.row-label {
  background: var(--gray-100);
  font-weight: 600;
  color: var(--gray-700);
  text-align: left;
}

/* === Interpretation Box === */
.interpretation {
  background: var(--green-light);
  border: 1px solid #c6f6d5;
  border-radius: var(--radius);
  padding: 1rem;
  margin-top: 1rem;
  font-size: 0.9rem;
  color: #276749;
}

.interpretation.warning {
  background: var(--orange-light);
  border-color: #fbd38d;
  color: #9c4221;
}

.interpretation.info {
  background: var(--blue-pale);
  border-color: #bee3f8;
  color: #2a4365;
}

/* === Reference Box === */
.reference-box {
  background: var(--gray-50);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  padding: 1rem;
  margin-top: 1rem;
  font-size: 0.8rem;
  color: var(--gray-500);
}

.reference-box strong {
  color: var(--gray-600);
}

/* === Disclaimer === */
.disclaimer {
  background: var(--orange-light);
  border: 1px solid #fbd38d;
  border-radius: var(--radius);
  padding: 1rem;
  margin: 1.5rem 0;
  font-size: 0.8rem;
  color: #9c4221;
  line-height: 1.5;
}

/* === Footer === */
.site-footer {
  background: var(--gray-800);
  color: var(--gray-400);
  padding: 2rem 0;
  margin-top: 3rem;
  text-align: center;
  font-size: 0.85rem;
}

.site-footer a {
  color: var(--gray-300);
}

.site-footer .footer-credits {
  margin-top: 0.5rem;
  font-size: 0.8rem;
  opacity: 0.7;
}

/* === Chart Container === */
.chart-container {
  margin: 1.5rem 0;
  text-align: center;
  overflow-x: auto;
}

.chart-container svg {
  max-width: 100%;
  height: auto;
}

/* === Study table (meta-analysis) === */
.study-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
  margin: 1rem 0;
}

.study-table th,
.study-table td {
  border: 1px solid var(--gray-300);
  padding: 0.4rem 0.6rem;
  text-align: center;
}

.study-table th {
  background: var(--gray-100);
  font-weight: 600;
  color: var(--gray-700);
}

.study-table input {
  width: 70px;
  text-align: center;
}

.study-table .study-name-input {
  width: 120px;
  text-align: left;
}

/* === Responsive === */
@media (max-width: 768px) {
  .hero h1 { font-size: 1.8rem; }
  .hero .subtitle { font-size: 1rem; }
  .calc-grid { grid-template-columns: 1fr; }
  .form-row { grid-template-columns: 1fr; }
  .site-header .container {
    flex-direction: column;
    align-items: flex-start;
  }
  .header-nav {
    width: 100%;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }
  .contingency-table td input { width: 60px; }
  .calc-section { padding: 1.25rem; }
  h1 { font-size: 1.5rem; }
  .result-highlight .big-number { font-size: 2rem; }
}

@media (max-width: 480px) {
  .radio-group { flex-direction: column; }
  .btn-group { flex-direction: column; }
  .btn { width: 100%; }
}

/* === Print === */
@media print {
  .site-header, .site-footer, .btn-group, .lang-toggle, .header-nav { display: none; }
  .calc-section { box-shadow: none; border: 1px solid #ccc; }
  .results-panel { display: block !important; }
  body { background: white; }
}

/* === 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-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }

/* Dynamic table sizing for chi-square */
.dynamic-table {
  overflow-x: auto;
}

.dynamic-table table {
  border-collapse: collapse;
  margin: 0.5rem 0;
}

.dynamic-table th,
.dynamic-table td {
  border: 1px solid var(--gray-300);
  padding: 0.4rem;
  text-align: center;
  min-width: 60px;
}

.dynamic-table th {
  background: var(--gray-100);
  font-weight: 600;
  font-size: 0.8rem;
}

.dynamic-table input {
  width: 60px;
  text-align: center;
}

/* Expected frequencies table */
.expected-table {
  width: 100%;
  border-collapse: collapse;
  margin: 0.5rem 0;
  font-size: 0.85rem;
}

.expected-table th,
.expected-table td {
  border: 1px solid var(--gray-300);
  padding: 0.35rem 0.5rem;
  text-align: center;
}

.expected-table th {
  background: var(--blue-pale);
  color: var(--navy);
  font-weight: 600;
}