/* ============================================================
   相関係数計算ツール — style.css
   Design System: Purple (#7c3aed), BG #f9f7f4
   ============================================================ */

:root {
  --primary: #7c3aed;
  --primary-hover: #6d28d9;
  --primary-rgb: 124, 58, 237;
  --primary-light: #ede9fe;
  --bg: #f9f7f4;
  --surface: #ffffff;
  --text: #1a1a2e;
  --text-muted: #6b7280;
  --text-weak: #9ca3af;
  --border: #e2e8f0;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,0.06), 0 4px 12px rgba(0,0,0,0.08);
  --shadow-hover: 0 4px 16px rgba(0,0,0,0.10), 0 1px 4px rgba(0,0,0,0.06);
  --transition: 0.15s ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Outfit', 'BIZ UDPGothic', -apple-system, BlinkMacSystemFont,
               'Hiragino Sans', 'Yu Gothic Medium', sans-serif;
  font-size: 0.9375rem;
  line-height: 1.75;
  color: var(--text);
  background: var(--bg);
  overflow-x: hidden;
  word-break: break-word;
}

/* ---- Header ---- */
header {
  background: var(--primary);
  color: #fff;
  padding: 1.75rem 1.25rem 1.5rem;
  text-align: center;
}

.header-inner {
  max-width: 860px;
  margin: 0 auto;
}

header h1 {
  font-size: clamp(1.3rem, 4vw, 1.8rem);
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: 0.01em;
}

header h1 .bi {
  margin-right: 0.35rem;
  opacity: 0.92;
}

.subtitle {
  font-size: 0.9rem;
  opacity: 0.88;
  margin-top: 0.4rem;
}

/* ---- Main Layout ---- */
main {
  max-width: 860px;
  margin: 0 auto;
  padding: 0 1.25rem 3rem;
}

/* ---- Ad Units ---- */
.ad-unit {
  min-height: 60px;
  background: #f0edf8;
  border: 1px dashed #c4b5fd;
  border-radius: var(--radius-sm);
  margin: 1.5rem 0;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #a78bfa;
  font-size: 0.8rem;
  letter-spacing: 0.05em;
}

.ad-unit::after {
  content: 'ADVERTISEMENT';
}

/* ---- Privacy Note ---- */
.privacy-note {
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
  background: #f0fdf4;
  border: 1px solid #bbf7d0;
  border-radius: var(--radius-sm);
  padding: 0.75rem 1rem;
  font-size: 0.875rem;
  color: #166534;
  margin-bottom: 1.5rem;
  line-height: 1.5;
}

.privacy-note .bi {
  flex-shrink: 0;
  margin-top: 0.1rem;
  font-size: 1rem;
}

/* ---- Tool Section ---- */
.tool-section {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
  border: 1px solid rgba(0,0,0,0.05);
  margin-top: 1.5rem;
}

/* ---- Input Grid ---- */
.input-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

@media (min-width: 640px) {
  .input-grid {
    grid-template-columns: 1fr 1fr;
    gap: 1.25rem;
  }
}

.input-col {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.col-header {
  display: flex;
  flex-direction: column;
  gap: 0.375rem;
}

.col-label {
  font-size: 0.875rem;
  font-weight: 600;
  color: #374151;
}

.var-name-input {
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.5rem 0.75rem;
  font-size: 1rem;
  font-family: inherit;
  background: #fff;
  min-height: 44px;
  width: 100%;
  transition: border-color var(--transition), box-shadow var(--transition);
  color: var(--text);
}

.var-name-input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(var(--primary-rgb), 0.15);
}

/* ---- Field ---- */
.field {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.field-label {
  font-size: 0.875rem;
  font-weight: 600;
  color: #374151;
}

.field-hint {
  font-size: 0.8125rem;
  color: var(--text-muted);
}

textarea {
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.625rem 0.75rem;
  font-size: 1rem;
  font-family: 'Outfit', 'BIZ UDPGothic', monospace;
  background: #fff;
  width: 100%;
  resize: vertical;
  transition: border-color var(--transition), box-shadow var(--transition);
  color: var(--text);
  line-height: 1.6;
}

textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(var(--primary-rgb), 0.15);
}

/* ---- Buttons ---- */
.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.25rem;
}

.btn-primary {
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: var(--radius-sm);
  padding: 0.625rem 1.5rem;
  font-size: 0.875rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
  box-shadow: 0 2px 8px rgba(var(--primary-rgb), 0.30);
  touch-action: manipulation;
}

.btn-primary:hover {
  background: var(--primary-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(var(--primary-rgb), 0.35);
}

.btn-primary:active {
  transform: translateY(0);
  box-shadow: none;
}

.btn-secondary {
  background: transparent;
  color: var(--primary);
  border: 1.5px solid var(--primary);
  border-radius: var(--radius-sm);
  padding: 0.625rem 1.25rem;
  font-size: 0.875rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
  touch-action: manipulation;
}

.btn-secondary:hover {
  background: var(--primary-light);
  transform: translateY(-1px);
  box-shadow: 0 2px 8px rgba(var(--primary-rgb), 0.15);
}

.btn-secondary:active {
  transform: translateY(0);
  box-shadow: none;
}

.btn-ghost {
  background: transparent;
  color: var(--text-muted);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.625rem 1rem;
  font-size: 0.875rem;
  font-weight: 500;
  font-family: inherit;
  cursor: pointer;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  transition: background var(--transition), color var(--transition);
}

.btn-ghost:hover {
  background: #f3f4f6;
  color: var(--text);
}

.btn-ghost:active {
  background: #e5e7eb;
}

/* ---- Error Message ---- */
.error-msg {
  background: #fef2f2;
  border: 1px solid #fecaca;
  border-radius: var(--radius-sm);
  padding: 0.75rem 1rem;
  color: #dc2626;
  font-size: 0.875rem;
  margin-top: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

/* ---- Results Area ---- */
.results-area {
  margin-top: 1.75rem;
  animation: fadeIn 0.25s ease-out;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ---- Result Headline ---- */
.result-headline {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
  margin-bottom: 1rem;
}

@media (min-width: 640px) {
  .result-headline {
    grid-template-columns: auto 1fr;
    align-items: start;
  }
}

.result-main-card {
  background: linear-gradient(135deg, #ede9fe, #f5f3ff);
  border: 1px solid #c4b5fd;
  border-radius: var(--radius);
  padding: 1.5rem 2rem;
  text-align: center;
  min-width: 180px;
}

.result-value {
  font-size: clamp(2.5rem, 8vw, 3.5rem);
  font-weight: 700;
  color: var(--primary);
  line-height: 1.1;
  font-family: 'Outfit', sans-serif;
  letter-spacing: -0.02em;
}

.result-label {
  font-size: 0.8125rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
  font-weight: 500;
}

.result-strength {
  margin-top: 0.5rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--primary);
}

/* ---- Sub Grid ---- */
.result-sub-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem;
}

@media (min-width: 480px) {
  .result-sub-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.result-sub-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.875rem 1rem;
  text-align: center;
  box-shadow: 0 1px 3px rgba(0,0,0,0.04);
  transition: box-shadow var(--transition), transform var(--transition);
}

.result-sub-card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-1px);
}

.sub-value {
  font-size: 1.375rem;
  font-weight: 700;
  color: var(--text);
  font-family: 'Outfit', sans-serif;
}

.sub-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 0.2rem;
}

.sub-note {
  font-size: 0.75rem;
  color: #6b7280;
  margin-top: 0.2rem;
}

/* ---- Significance Badge ---- */
.sig-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.5rem 1.125rem;
  border-radius: 100px;
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.sig-badge.sig-yes {
  background: #d1fae5;
  color: #065f46;
  border: 1px solid #6ee7b7;
}

.sig-badge.sig-no {
  background: #f3f4f6;
  color: #4b5563;
  border: 1px solid #d1d5db;
}

/* ---- Regression Equation ---- */
.regression-eq {
  background: #faf5ff;
  border: 1px solid #e9d5ff;
  border-radius: var(--radius-sm);
  padding: 0.75rem 1rem;
  margin-bottom: 1.25rem;
  font-size: 0.9375rem;
}

.eq-label {
  font-weight: 600;
  color: var(--text-muted);
  margin-right: 0.5rem;
}

.eq-text {
  font-family: 'Outfit', monospace;
  font-weight: 600;
  color: var(--primary);
}

/* ---- Chart ---- */
.chart-wrap {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  box-shadow: var(--shadow);
  position: relative;
}

.chart-wrap canvas {
  max-height: 400px;
  width: 100% !important;
}

/* ---- Chart Download Row ---- */
.chart-download-row {
  display: flex;
  justify-content: flex-end;
  margin-top: 0.75rem;
}

/* ---- How-to Section ---- */
.howto-section {
  margin-top: 2rem;
}

.howto-section h2 {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--primary-light);
}

/* ---- Details / Accordion ---- */
details {
  background: var(--surface);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  margin-bottom: 0.75rem;
  overflow: hidden;
  transition: box-shadow var(--transition);
  box-shadow: var(--shadow);
}

details:hover {
  box-shadow: var(--shadow-hover);
}

details[open] {
  box-shadow: var(--shadow-hover);
}

summary {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 1rem 1.25rem;
  font-weight: 600;
  font-size: 0.9375rem;
  cursor: pointer;
  color: var(--text);
  user-select: none;
  list-style: none;
  min-height: 52px;
  transition: background var(--transition);
}

summary::-webkit-details-marker {
  display: none;
}

summary::after {
  content: '\f282';
  font-family: 'bootstrap-icons';
  margin-left: auto;
  color: var(--text-muted);
  transition: transform 0.2s ease;
  font-size: 0.9rem;
}

details[open] summary::after {
  transform: rotate(180deg);
}

summary:hover {
  background: #f9f5ff;
}

summary .bi {
  color: var(--primary);
  font-size: 1rem;
}

.details-body {
  padding: 0 1.25rem 1.25rem;
  color: var(--text);
}

.details-body h3 {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text);
  margin: 1rem 0 0.5rem;
}

.details-body p {
  font-size: 0.9rem;
  line-height: 1.75;
  color: #374151;
  margin-bottom: 0.75rem;
}

/* ---- Steps List ---- */
.steps {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.875rem;
}

.steps li {
  display: flex;
  align-items: flex-start;
  gap: 0.875rem;
}

.step-num {
  width: 28px;
  height: 28px;
  background: var(--primary);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8125rem;
  font-weight: 700;
  flex-shrink: 0;
  margin-top: 0.1rem;
}

.steps li div {
  font-size: 0.9rem;
  line-height: 1.65;
  color: #374151;
}

/* ---- Note Box ---- */
.note-box {
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
  background: #fef9c3;
  border: 1px solid #fde68a;
  border-radius: var(--radius-sm);
  padding: 0.75rem 1rem;
  font-size: 0.875rem !important;
  color: #92400e !important;
  margin-top: 1rem;
  margin-bottom: 0 !important;
}

.note-box .bi {
  color: #d97706;
  flex-shrink: 0;
  margin-top: 0.1rem;
}

/* ---- Info Table ---- */
.info-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
  margin: 0.75rem 0 1rem;
  overflow: hidden;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}

.info-table thead tr {
  background: var(--primary-light);
}

.info-table th {
  padding: 0.6rem 0.875rem;
  text-align: left;
  font-weight: 600;
  color: #5b21b6;
  font-size: 0.8125rem;
}

.info-table td {
  padding: 0.6rem 0.875rem;
  border-top: 1px solid var(--border);
  color: #374151;
}

.info-table tbody tr:nth-child(even) {
  background: #faf5ff;
}

/* ---- Use Cases ---- */
.use-cases {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.use-cases li {
  padding: 0.875rem 1rem;
  background: #faf5ff;
  border-radius: var(--radius-sm);
  border-left: 3px solid var(--primary);
  font-size: 0.9rem;
  line-height: 1.65;
  color: #374151;
}

.use-cases li strong {
  display: block;
  margin-bottom: 0.2rem;
  color: var(--primary);
}

/* ---- FAQ ---- */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 0.875rem;
}

.faq-item {
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.faq-q {
  background: var(--primary-light);
  padding: 0.75rem 1rem;
  font-weight: 600;
  font-size: 0.9rem;
  color: #5b21b6;
  display: flex;
  align-items: center;
  gap: 0.4rem;
  margin: 0 !important;
}

.faq-q .bi {
  font-size: 1rem;
  flex-shrink: 0;
}

.faq-a {
  padding: 0.75rem 1rem !important;
  font-size: 0.875rem !important;
  color: #374151 !important;
  margin: 0 !important;
  line-height: 1.7;
}

/* ---- Disclaimer ---- */
.disclaimer-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.disclaimer-list li {
  padding-left: 1.25rem;
  position: relative;
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.65;
}

.disclaimer-list li::before {
  content: '•';
  position: absolute;
  left: 0;
  color: var(--primary);
}

/* ---- Footer ---- */
footer {
  background: #1a1a2e;
  color: #9ca3af;
  padding: 1.5rem 1.25rem;
  text-align: center;
  font-size: 0.875rem;
}

.footer-inner {
  max-width: 860px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 0.375rem;
}

footer a {
  color: #c4b5fd;
  text-decoration: none;
  transition: color var(--transition);
}

footer a:hover {
  color: #a78bfa;
  text-decoration: underline;
}

footer small {
  font-size: 0.8125rem;
  color: #6b7280;
}

/* ---- Responsive: Desktop ---- */
@media (min-width: 900px) {
  .tool-section {
    padding: 2rem;
  }

  main {
    padding-top: 0.5rem;
  }
}