/* =============================================
   損益分岐点計算ツール — style.css
   Design: Mobile-first, amber/business theme
   ============================================= */

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

:root {
  --primary: #d97706;
  --primary-hover: #b45309;
  --primary-rgb: 217, 119, 6;
  --primary-soft: #fffbeb;
  --primary-light: #fef3c7;
  --profit-color: #16a34a;
  --profit-rgb: 22, 163, 74;
  --loss-color: #dc2626;
  --bg: #f9f7f4;
  --surface: #ffffff;
  --text: #1a1a2e;
  --muted: #6b7280;
  --border: #e5e7eb;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.06), 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-hover: 0 6px 20px rgba(0, 0, 0, 0.12), 0 2px 6px rgba(0, 0, 0, 0.06);
  --transition: 0.15s ease;
}

body {
  font-family: 'Outfit', 'BIZ UDPGothic', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.75;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3 {
  letter-spacing: -0.02em;
}

/* ===== Header ===== */
header {
  background: linear-gradient(135deg, #92400e 0%, #d97706 55%, #f59e0b 100%);
  color: white;
  padding: 2.25rem 1.25rem 2rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}

header::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 20% 70%, rgba(255, 255, 255, 0.07) 0%, transparent 55%),
    radial-gradient(ellipse at 80% 15%, rgba(255, 255, 255, 0.05) 0%, transparent 50%);
  pointer-events: none;
}

.header-inner {
  position: relative;
  max-width: 760px;
  margin: 0 auto;
}

.header-icon {
  font-size: 2.25rem;
  margin-bottom: 0.5rem;
  line-height: 1;
  opacity: 0.95;
}

header h1 {
  font-size: clamp(1.1rem, 4vw, 1.55rem);
  font-weight: 800;
  line-height: 1.35;
}

.header-sub {
  margin-top: 0.4rem;
  font-size: 0.875rem;
  opacity: 0.88;
}

/* ===== Main ===== */
main {
  max-width: 760px;
  margin: 0 auto;
  padding: 1.5rem 1rem 3rem;
}

/* ===== Privacy notice ===== */
.privacy-notice {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  background: #ecfdf5;
  border: 1px solid #bbf7d0;
  border-radius: 8px;
  padding: 0.625rem 0.875rem;
  font-size: 0.8125rem;
  color: #166534;
  margin-bottom: 1rem;
}

.privacy-notice .bi {
  font-size: 0.9rem;
  flex-shrink: 0;
  color: #16a34a;
}

/* ===== Card ===== */
.card {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
  border: 1px solid rgba(0, 0, 0, 0.04);
  margin-bottom: 1rem;
}

/* ===== Section title ===== */
.section-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 1.25rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.section-title .bi {
  color: var(--primary);
}

/* ===== Mode toggle ===== */
.mode-toggle {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1.25rem;
  background: var(--bg);
  border-radius: 10px;
  padding: 0.25rem;
}

.mode-btn {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  padding: 0.5rem 0.75rem;
  font-size: 0.8125rem;
  font-weight: 600;
  font-family: inherit;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  background: transparent;
  color: var(--muted);
  min-height: 44px;
  transition: background var(--transition), color var(--transition), box-shadow var(--transition);
}

.mode-btn.active {
  background: var(--surface);
  color: var(--primary);
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.1);
}

.mode-btn:hover:not(.active) {
  color: var(--text);
  background: rgba(255, 255, 255, 0.6);
}

/* ===== Form grid ===== */
.form-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

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

.field-label {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 0.35rem;
  flex-wrap: wrap;
}

.field-label .bi {
  color: var(--primary);
}

.field-hint {
  font-size: 0.8125rem;
  color: var(--muted);
  line-height: 1.5;
}

.optional-badge {
  display: inline-block;
  font-size: 0.68rem;
  font-weight: 700;
  padding: 0.05rem 0.5rem;
  border-radius: 100px;
  background: #f3f4f6;
  color: var(--muted);
  margin-left: 0.25rem;
}

.input-wrap {
  position: relative;
  display: flex;
  align-items: center;
}

.form-input {
  width: 100%;
  padding: 0.75rem 1rem;
  padding-right: 4rem;
  font-size: 1rem;
  font-family: inherit;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  color: var(--text);
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
  min-height: 44px;
}

.form-input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(var(--primary-rgb), 0.15);
}

.form-input::placeholder {
  color: #b0b7c0;
}

/* Remove number input arrows */
.form-input[type="number"]::-webkit-inner-spin-button,
.form-input[type="number"]::-webkit-outer-spin-button {
  opacity: 0.4;
}

.input-suffix {
  position: absolute;
  right: 0.875rem;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--muted);
  pointer-events: none;
  white-space: nowrap;
}

/* ===== Calculate button ===== */
.btn-calc {
  width: 100%;
  padding: 0.875rem 1.5rem;
  font-size: 1rem;
  font-weight: 700;
  font-family: inherit;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  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);
}

.btn-calc:hover {
  background: var(--primary-hover);
  box-shadow: 0 4px 14px rgba(var(--primary-rgb), 0.45);
  transform: translateY(-1px);
}

.btn-calc:active {
  transform: translateY(0);
  box-shadow: 0 1px 4px rgba(var(--primary-rgb), 0.3);
}

/* ===== Results area ===== */
.results-area {
  margin-top: 0;
}

/* ===== KPI Grid ===== */
.kpi-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.kpi-card {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  box-shadow: var(--shadow);
  border: 1px solid rgba(0, 0, 0, 0.04);
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  transition: box-shadow var(--transition), transform var(--transition);
}

.kpi-card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-2px);
}

.kpi-bep {
  border-top: 3px solid var(--primary);
}

.kpi-units {
  border-top: 3px solid #7c3aed;
}

.kpi-margin {
  border-top: 3px solid #0f766e;
}

.kpi-icon {
  font-size: 1.1rem;
  margin-bottom: 0.25rem;
}

.kpi-bep .kpi-icon { color: var(--primary); }
.kpi-units .kpi-icon { color: #7c3aed; }
.kpi-margin .kpi-icon { color: #0f766e; }

.kpi-label {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--muted);
}

.kpi-value {
  font-size: clamp(1.75rem, 6vw, 2.5rem);
  font-weight: 800;
  line-height: 1.1;
  color: var(--text);
  letter-spacing: -0.02em;
}

.kpi-bep .kpi-value { color: var(--primary); }
.kpi-units .kpi-value { color: #7c3aed; }
.kpi-margin .kpi-value { color: #0f766e; }

.kpi-unit {
  font-size: 0.8125rem;
  color: var(--muted);
}

/* ===== Safety card ===== */
.safety-card {
  border-left: 4px solid var(--primary);
}

.safety-header {
  display: flex;
  align-items: flex-start;
  gap: 0.875rem;
  margin-bottom: 1rem;
}

.safety-icon {
  width: 42px;
  height: 42px;
  border-radius: 10px;
  background: var(--primary-soft);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  flex-shrink: 0;
}

.safety-card h3 {
  font-size: 0.9375rem;
  font-weight: 700;
  margin-bottom: 0.15rem;
}

.safety-desc {
  font-size: 0.8125rem;
  color: var(--muted);
}

.safety-value-wrap {
  margin-left: auto;
  flex-shrink: 0;
}

.safety-value {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: -0.02em;
}

.safety-bar-wrap {
  margin-bottom: 0.75rem;
}

.safety-bar-bg {
  height: 10px;
  background: #f3f4f6;
  border-radius: 100px;
  overflow: hidden;
  margin-bottom: 0.375rem;
}

.safety-bar-fill {
  height: 100%;
  border-radius: 100px;
  background: linear-gradient(90deg, #dc2626 0%, #f59e0b 40%, #16a34a 70%);
  transition: width 0.4s ease;
  min-width: 2px;
}

.safety-bar-labels {
  display: flex;
  justify-content: space-between;
  font-size: 0.675rem;
  color: var(--muted);
  font-weight: 500;
}

.safety-note {
  font-size: 0.8125rem;
  color: #374151;
  background: var(--bg);
  padding: 0.5rem 0.75rem;
  border-radius: 6px;
  line-height: 1.6;
}

/* ===== Target card ===== */
.target-card {
  border-left: 4px solid #7c3aed;
}

.target-header {
  display: flex;
  align-items: flex-start;
  gap: 0.875rem;
  margin-bottom: 1rem;
}

.target-icon {
  width: 42px;
  height: 42px;
  border-radius: 10px;
  background: #f5f3ff;
  color: #7c3aed;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  flex-shrink: 0;
}

.target-card h3 {
  font-size: 0.9375rem;
  font-weight: 700;
  margin-bottom: 0.15rem;
}

.target-desc {
  font-size: 0.8125rem;
  color: var(--muted);
}

.target-kpi-row {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.target-kpi {
  flex: 1;
  min-width: 120px;
  background: #f5f3ff;
  border-radius: 10px;
  padding: 0.875rem 1rem;
}

.target-kpi-label {
  font-size: 0.75rem;
  font-weight: 600;
  color: #7c3aed;
  margin-bottom: 0.25rem;
}

.target-kpi-value {
  font-size: clamp(1.2rem, 4vw, 1.75rem);
  font-weight: 800;
  color: #5b21b6;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

.target-kpi-unit {
  font-size: 0.75rem;
  color: #6d28d9;
  margin-top: 0.15rem;
}

/* ===== Ad unit ===== */
.ad-unit {
  background: #f3f4f6;
  border-radius: 8px;
  min-height: 0;
  margin-bottom: 1rem;
  overflow: hidden;
}

/* ===== Chart card ===== */
.chart-card {
  overflow: hidden;
}

.chart-title {
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.chart-title .bi {
  color: var(--primary);
}

.chart-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.8rem;
  color: var(--muted);
  font-weight: 500;
}

.legend-dot {
  width: 12px;
  height: 4px;
  border-radius: 2px;
  display: inline-block;
}

.legend-revenue { background: #16a34a; }
.legend-cost    { background: #dc2626; }
.legend-fixed   { background: #6b7280; }

.legend-bep {
  color: var(--primary);
  font-weight: 700;
}

.legend-bep .bi {
  font-size: 0.8rem;
}

.chart-wrap {
  position: relative;
  width: 100%;
  height: 260px;
}

.chart-note {
  font-size: 0.775rem;
  color: var(--muted);
  margin-top: 0.75rem;
  display: flex;
  align-items: flex-start;
  gap: 0.3rem;
  line-height: 1.5;
}

.chart-note .bi {
  flex-shrink: 0;
  margin-top: 0.1rem;
}

/* ===== Breakdown table ===== */
.breakdown-title {
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 0.875rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.breakdown-title .bi {
  color: var(--primary);
}

.breakdown-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.8125rem;
}

.breakdown-table tr {
  border-bottom: 1px solid #f3f4f6;
}

.breakdown-table tr:last-child {
  border-bottom: none;
}

.breakdown-table td {
  padding: 0.5rem 0.25rem;
  vertical-align: middle;
  line-height: 1.5;
}

.breakdown-table .row-label {
  color: var(--muted);
  font-weight: 500;
  width: 55%;
}

.breakdown-table .row-value {
  font-weight: 700;
  color: var(--text);
  text-align: right;
}

.breakdown-table .row-highlight {
  color: var(--primary);
  font-size: 0.9375rem;
}

/* ===== How-to section ===== */
.howto-section {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
  border: 1px solid rgba(0, 0, 0, 0.04);
  margin-top: 1rem;
}

.howto-section h2 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
  margin-top: 1.5rem;
  margin-bottom: 0.75rem;
  padding-bottom: 0.4rem;
  border-bottom: 2px solid var(--primary-light);
}

.howto-section h2:first-child {
  margin-top: 0;
}

.howto-section p {
  font-size: 0.875rem;
  color: #374151;
  line-height: 1.8;
  margin-bottom: 0.75rem;
}

.howto-details {
  margin-bottom: 1rem;
}

.howto-summary {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 0.875rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--primary);
  background: var(--primary-soft);
  border-radius: 8px;
  cursor: pointer;
  list-style: none;
  min-height: 44px;
  -webkit-tap-highlight-color: transparent;
  user-select: none;
  border: 1px solid var(--primary-light);
}

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

.howto-summary:hover {
  background: var(--primary-light);
}

.howto-steps {
  padding-left: 1.25rem;
  font-size: 0.875rem;
  color: #374151;
  line-height: 1.9;
  margin-top: 0.75rem;
}

.howto-steps li {
  margin-bottom: 0.25rem;
}

/* ===== Accordion ===== */
.accordion-group {
  margin-top: 1.5rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.accordion-item {
  border-bottom: 1px solid var(--border);
}

.accordion-item:last-child {
  border-bottom: none;
}

.accordion-summary {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.9rem 1.1rem;
  cursor: pointer;
  font-weight: 600;
  font-size: 0.95rem;
  list-style: none;
  background: #fff;
  min-height: 44px;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
  user-select: none;
  transition: background var(--transition);
}

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

.accordion-summary:hover {
  background: #f8fafb;
}

.accordion-icon::after {
  content: '+';
  font-size: 1.2rem;
  font-weight: 400;
  color: var(--muted);
  display: inline-block;
  width: 20px;
  text-align: center;
}

details[open] > .accordion-summary .accordion-icon::after {
  content: '−';
}

.accordion-body {
  padding: 0.25rem 1.1rem 1.1rem;
  background: #fff;
}

.accordion-body p,
.accordion-body dl,
.accordion-body ul,
.accordion-body ol {
  font-size: 0.875rem;
  color: #374151;
}

.accordion-body dt {
  font-weight: 700;
  color: var(--text);
  margin-top: 0.875rem;
}

.accordion-body dt:first-child {
  margin-top: 0;
}

.accordion-body dd {
  margin-left: 0;
  color: #4b5563;
  margin-top: 0.2rem;
  margin-bottom: 0.5rem;
  line-height: 1.75;
}

.accordion-body ul,
.accordion-body ol {
  padding-left: 1.25rem;
}

.accordion-body li {
  margin-bottom: 0.3rem;
}

.accordion-body table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.8125rem;
  margin-top: 0.5rem;
}

.accordion-body table th,
.accordion-body table td {
  padding: 0.6rem 0.75rem;
  border: 1px solid var(--border);
  text-align: left;
  vertical-align: top;
  line-height: 1.6;
}

.accordion-body table thead tr {
  background: var(--primary-soft);
}

.accordion-body table th {
  font-weight: 700;
  color: var(--primary);
  font-size: 0.75rem;
}

.accordion-body table tbody tr:nth-child(even) {
  background: #fafafa;
}

.disclaimer-note {
  font-size: 0.8rem;
  color: #6b7280;
  background: #f8f9fa;
  border-left: 3px solid #d1d5db;
  padding: 0.625rem 0.875rem;
  border-radius: 0 6px 6px 0;
  line-height: 1.7;
  margin-top: 0;
}

.disclaimer-note strong {
  color: #374151;
}

/* ===== Footer ===== */
footer {
  text-align: center;
  padding: 2.5rem 1.25rem;
  font-size: 0.85rem;
  color: #9ca3af;
  border-top: 1px solid var(--border);
}

footer a {
  color: #6b7280;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  transition: color var(--transition);
}

footer a:hover {
  text-decoration: underline;
  color: var(--primary);
}

footer p + p {
  margin-top: 0.5rem;
}

/* ===== Responsive ===== */
@media (min-width: 480px) {
  .kpi-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (min-width: 640px) {
  main {
    padding: 2rem 1.25rem 3.5rem;
  }

  .card {
    padding: 1.75rem;
  }

  .howto-section {
    padding: 1.75rem;
  }

  .form-grid {
    grid-template-columns: 1fr 1fr;
  }

  .chart-wrap {
    height: 320px;
  }
}

@media (min-width: 900px) {
  .chart-wrap {
    height: 380px;
  }
}

@media (max-width: 400px) {
  .mode-btn {
    font-size: 0.75rem;
    padding: 0.5rem 0.5rem;
    gap: 0.2rem;
  }

  .target-kpi-row {
    flex-direction: column;
  }

  .target-kpi {
    min-width: unset;
  }
}