/* ===========================
   正規分布 確率計算ツール
   style.css
   =========================== */

:root {
  --primary: #0891b2;
  --primary-hover: #0e7490;
  --primary-rgb: 8, 145, 178;
  --primary-light: #cffafe;
  --primary-pale: #f0fdff;
  --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;

  /* 計算タイプ別カラー */
  --color-lower: #0891b2;
  --color-lower-fill: rgba(8, 145, 178, 0.25);
  --color-upper: #7c3aed;
  --color-upper-fill: rgba(124, 58, 237, 0.22);
  --color-interval: #059669;
  --color-interval-fill: rgba(5, 150, 105, 0.22);
}

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

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

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

/* ===========================
   Header
   =========================== */
header {
  background: linear-gradient(135deg, var(--primary) 0%, #0e7490 100%);
  color: #fff;
  padding: 2rem 1.25rem 1.75rem;
  text-align: center;
}
.header-inner { max-width: 700px; margin: 0 auto; }
.header-icon {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
  opacity: 0.9;
}
header h1 {
  font-size: clamp(1.3rem, 4vw, 1.9rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.25;
}
.header-sub {
  font-size: 0.9rem;
  opacity: 0.88;
  margin-top: 0.4rem;
  line-height: 1.55;
}

/* ===========================
   Main Layout
   =========================== */
main {
  max-width: 780px;
  margin: 0 auto;
  padding: 1.5rem 1rem 3rem;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

/* ===========================
   Card
   =========================== */
.card {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
  border: 1px solid rgba(0,0,0,0.05);
}

/* ===========================
   Ad Unit
   =========================== */
.ad-unit {
  min-height: 90px;
  background: #f1f5f9;
  border-radius: var(--radius-sm);
  border: 1px dashed #cbd5e1;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-weak);
  font-size: 0.8rem;
}

/* ===========================
   Privacy Note
   =========================== */
.privacy-note {
  font-size: 0.8rem;
  color: var(--text-muted);
  background: #f0fdff;
  border: 1px solid #a5f3fc;
  border-radius: var(--radius-sm);
  padding: 0.5rem 0.875rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}
.privacy-note i { color: var(--primary); flex-shrink: 0; }

/* ===========================
   Mode Tabs
   =========================== */
.mode-tabs {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
  border-bottom: 2px solid var(--border);
  padding-bottom: 0;
}
.mode-tab {
  background: none;
  border: none;
  border-bottom: 3px solid transparent;
  margin-bottom: -2px;
  padding: 0.5rem 1rem;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.35rem;
  transition: color var(--transition), border-color var(--transition);
  min-height: 44px;
  border-radius: 0;
}
.mode-tab:hover { color: var(--primary); }
.mode-tab.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
}

/* ===========================
   Form
   =========================== */
.param-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-bottom: 1.25rem;
}
.field {
  display: flex;
  flex-direction: column;
  gap: 0.375rem;
}
.field-label {
  font-size: 0.875rem;
  font-weight: 600;
  color: #374151;
}
.field-hint {
  font-size: 0.8rem;
  color: var(--text-muted);
}
.field-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;
  color: var(--text);
  transition: border-color var(--transition), box-shadow var(--transition);
  min-height: 44px;
  width: 100%;
}
.field-input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(var(--primary-rgb), 0.15);
}
.field-input::-webkit-inner-spin-button,
.field-input::-webkit-outer-spin-button { opacity: 0.6; }

/* ===========================
   Calc Type Radio
   =========================== */
.calc-type-group {
  border: none;
  margin-bottom: 1.25rem;
}
.calc-type-group legend { margin-bottom: 0.5rem; }
.radio-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}
.radio-label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  color: var(--text);
  cursor: pointer;
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-sm);
  border: 1.5px solid var(--border);
  background: #fff;
  transition: border-color var(--transition), background var(--transition);
  min-height: 44px;
  user-select: none;
}
.radio-label:hover {
  border-color: var(--primary);
  background: var(--primary-pale);
}
.radio-label input[type="radio"] { display: none; }
.radio-custom {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  border: 2px solid var(--border);
  flex-shrink: 0;
  background: #fff;
  transition: border-color var(--transition), background var(--transition);
  position: relative;
}
.radio-custom::after {
  content: '';
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%) scale(0);
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--primary);
  transition: transform 0.12s ease;
}
.radio-label input[type="radio"]:checked + .radio-custom {
  border-color: var(--primary);
}
.radio-label input[type="radio"]:checked + .radio-custom::after {
  transform: translate(-50%, -50%) scale(1);
}
.radio-label:has(input[type="radio"]:checked) {
  border-color: var(--primary);
  background: var(--primary-pale);
}

/* ===========================
   Bound Row
   =========================== */
.bound-row {
  display: flex;
  align-items: flex-end;
  gap: 0.75rem;
  margin-bottom: 1.25rem;
}
.bound-row .field { flex: 1; }
.bound-separator {
  display: flex;
  align-items: center;
  padding-bottom: 0.6rem;
}
.separator-label {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-muted);
}

/* ===========================
   Z Presets
   =========================== */
.z-presets { margin-bottom: 1.25rem; }
.preset-btns {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}
.preset-btn {
  background: #f1f5f9;
  border: 1.5px solid var(--border);
  border-radius: 100px;
  padding: 0.35rem 0.85rem;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
  cursor: pointer;
  transition: all var(--transition);
  min-height: 44px;
}
.preset-btn:hover {
  background: var(--primary-pale);
  border-color: var(--primary);
  color: var(--primary);
}
.preset-btn:active { transform: scale(0.97); }
.preset-btn small { font-weight: 400; opacity: 0.8; }

/* ===========================
   Primary Button
   =========================== */
.btn-primary {
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: var(--radius-sm);
  padding: 0.625rem 2rem;
  font-size: 1rem;
  font-weight: 700;
  font-family: inherit;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  width: 100%;
  min-height: 52px;
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
  box-shadow: 0 2px 8px rgba(var(--primary-rgb), 0.35);
  letter-spacing: 0.01em;
}
.btn-primary:hover {
  background: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(var(--primary-rgb), 0.38);
}
.btn-primary:active {
  transform: translateY(0);
  box-shadow: 0 1px 4px rgba(var(--primary-rgb), 0.25);
}

/* ===========================
   Section Title
   =========================== */
.section-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 0.4rem;
  margin-bottom: 1rem;
}
.section-title i { color: var(--primary); }

/* ===========================
   Chart
   =========================== */
.chart-wrapper {
  position: relative;
  width: 100%;
  height: 260px;
}
.sigma-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 0.875rem;
  justify-content: center;
}
.legend-item {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.8rem;
  color: var(--text-muted);
}
.legend-dot {
  width: 10px; height: 10px;
  border-radius: 2px;
  flex-shrink: 0;
}
.sigma-1 .legend-dot { background: rgba(8,145,178,0.4); }
.sigma-2 .legend-dot { background: rgba(8,145,178,0.25); }
.sigma-3 .legend-dot { background: rgba(8,145,178,0.12); }

/* ===========================
   Result Card
   =========================== */
.empty-state {
  text-align: center;
  padding: 2.5rem 1rem;
  color: var(--text-weak);
}
.empty-icon { font-size: 2.5rem; margin-bottom: 0.75rem; color: var(--primary); opacity: 0.4; }
.empty-title { font-size: 1rem; color: var(--text-muted); font-weight: 600; }
.empty-desc { font-size: 0.875rem; margin-top: 0.25rem; }

/* Result main value */
.result-main {
  background: linear-gradient(135deg, var(--primary-pale), #f0f9ff);
  border: 1px solid #a5f3fc;
  border-radius: var(--radius);
  padding: 1.5rem;
  text-align: center;
  margin-bottom: 1rem;
}
.result-label-top {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--primary);
  margin-bottom: 0.25rem;
  letter-spacing: 0.01em;
}
.result-value {
  font-size: clamp(2.5rem, 8vw, 4rem);
  font-weight: 800;
  color: var(--primary);
  line-height: 1.1;
  font-family: 'Outfit', sans-serif;
  letter-spacing: -0.03em;
}
.result-value-sub {
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-muted);
  margin-top: 0.25rem;
  font-family: 'Outfit', monospace;
}

/* z値モード: 3列確率カード */
.z-result-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.625rem;
  margin-bottom: 1rem;
}
.z-result-card {
  background: #f0fdff;
  border: 1px solid #a5f3fc;
  border-radius: var(--radius-sm);
  padding: 0.75rem 0.5rem;
  text-align: center;
}
.z-result-card--upper {
  background: #f5f3ff;
  border-color: #c4b5fd;
}
.z-result-card--two {
  background: #f0fdf4;
  border-color: #86efac;
}
.z-result-card-label {
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-bottom: 0.25rem;
  line-height: 1.35;
}
.z-result-card-value {
  font-size: 1.1rem;
  font-weight: 800;
  color: var(--text);
  font-family: 'Outfit', sans-serif;
  line-height: 1.2;
  margin-bottom: 0.2rem;
}
.z-result-card-hint {
  font-size: 0.7rem;
  color: var(--text-muted);
}
.z-result-card--upper .z-result-card-value { color: var(--color-upper); }
.z-result-card--two .z-result-card-value   { color: var(--color-interval); }

/* Sub grid */
.result-sub-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin-bottom: 1rem;
}
.result-sub-item {
  background: #f8fafc;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.875rem 1rem;
  text-align: center;
}
.result-sub-label {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.25rem;
}
.result-sub-value {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--text);
  font-family: 'Outfit', sans-serif;
  line-height: 1.2;
}
.result-sub-hint {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 0.2rem;
}

/* Interpretation */
.interpretation {
  background: #fffbeb;
  border: 1px solid #fde68a;
  border-radius: var(--radius-sm);
  padding: 0.75rem 1rem;
  font-size: 0.9rem;
  color: #92400e;
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
  margin-bottom: 1rem;
  line-height: 1.6;
}
.interpretation i { color: #d97706; flex-shrink: 0; margin-top: 0.15rem; }

/* σ rule table */
.sigma-rule-table { margin-top: 0.5rem; }
.sigma-rule-title {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 0.35rem;
  margin-bottom: 0.5rem;
}
.sigma-rule-table table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
}
.sigma-rule-table th, .sigma-rule-table td {
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--border);
  text-align: center;
}
.sigma-rule-table th {
  background: #f1f5f9;
  font-weight: 600;
  font-size: 0.8rem;
  color: var(--text-muted);
}
.sigma-rule-table td { color: var(--text); }

/* Error */
.error-msg {
  background: #fef2f2;
  border: 1px solid #fecaca;
  border-radius: var(--radius-sm);
  padding: 0.875rem 1rem;
  color: #991b1b;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  font-weight: 500;
}
.error-msg i { flex-shrink: 0; font-size: 1rem; }

/* ===========================
   Howto Section
   =========================== */
.howto-section {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
  border: 1px solid rgba(0,0,0,0.05);
}
.howto-section h2 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 0.875rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--primary-light);
}
.howto-steps {
  padding-left: 1.25rem;
  margin-bottom: 1.5rem;
}
.howto-steps li {
  font-size: 0.9375rem;
  line-height: 1.75;
  color: var(--text);
  margin-bottom: 0.35rem;
}

/* ===========================
   Accordion
   =========================== */
.accordion-group { display: flex; flex-direction: column; gap: 0.5rem; }
.accordion-item {
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  overflow: hidden;
}
.accordion-summary {
  padding: 0.875rem 1rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text);
  background: #fafafa;
  list-style: none;
  user-select: none;
  min-height: 48px;
  transition: background var(--transition);
}
.accordion-summary::-webkit-details-marker { display: none; }
.accordion-summary:hover { background: var(--primary-pale); color: var(--primary); }
.accordion-icon {
  width: 20px; height: 20px;
  flex-shrink: 0;
  position: relative;
}
.accordion-icon::before, .accordion-icon::after {
  content: '';
  position: absolute;
  background: currentColor;
  border-radius: 2px;
  transition: transform 0.2s ease, opacity 0.2s ease;
}
.accordion-icon::before { width: 10px; height: 2px; top: 9px; left: 5px; }
.accordion-icon::after { width: 2px; height: 10px; top: 5px; left: 9px; }
details[open] .accordion-icon::after { transform: rotate(90deg); opacity: 0; }
.accordion-body {
  padding: 1rem 1rem 1.25rem;
  font-size: 0.9rem;
  line-height: 1.75;
  color: var(--text);
  border-top: 1px solid var(--border);
  background: #fff;
}
.accordion-body p { margin-bottom: 0.75rem; }
.accordion-body p:last-child { margin-bottom: 0; }
.accordion-body ul, .accordion-body ol {
  padding-left: 1.25rem;
  margin-bottom: 0.75rem;
}
.accordion-body li { margin-bottom: 0.25rem; }
.accordion-body dl dt {
  font-weight: 700;
  color: var(--primary);
  margin-top: 0.875rem;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}
.accordion-body dl dt:first-child { margin-top: 0; }
.accordion-body dl dd {
  padding-left: 1rem;
  color: var(--text);
  margin-bottom: 0.25rem;
}
.ref-links {
  list-style: disc;
  padding-left: 1.25rem;
  margin-bottom: 0.875rem;
  font-size: 0.875rem;
  color: var(--text-muted);
}
.disclaimer-note {
  font-size: 0.8125rem;
  color: var(--text-muted);
  background: #f8fafc;
  border-left: 3px solid var(--border);
  padding: 0.5rem 0.75rem;
  border-radius: 0 4px 4px 0;
  line-height: 1.65;
}

/* ===========================
   Footer
   =========================== */
footer {
  background: #1e293b;
  color: #94a3b8;
  text-align: center;
  padding: 1.75rem 1.25rem;
  font-size: 0.875rem;
  line-height: 2;
}
footer a {
  color: #cbd5e1;
  text-decoration: none;
  transition: color var(--transition);
}
footer a:hover { color: #fff; }
footer small { font-size: 0.8rem; color: #64748b; }

/* ===========================
   Responsive
   =========================== */
@media (max-width: 480px) {
  .param-row {
    grid-template-columns: 1fr;
    gap: 0.75rem;
  }
  .result-sub-grid {
    grid-template-columns: 1fr;
  }
  .bound-row {
    flex-direction: column;
    align-items: stretch;
  }
  .bound-separator {
    display: none;
  }
  .preset-btns { gap: 0.35rem; }
  .preset-btn { font-size: 0.75rem; padding: 0.3rem 0.65rem; min-height: 44px; }
  .chart-wrapper { height: 210px; }
  .z-result-cards { grid-template-columns: 1fr; }
  .z-result-card-value { font-size: 1rem; }
  .card { padding: 1.125rem; }
  .howto-section { padding: 1.125rem; }
}

@media (min-width: 640px) {
  main { padding: 1.75rem 1.25rem 3rem; }
  .radio-group {
    flex-direction: row;
    flex-wrap: wrap;
  }
  .radio-label { flex: 1; min-width: 160px; }
}

@media (min-width: 780px) {
  .chart-wrapper { height: 300px; }
}