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

:root {
  --blue:     #2563EB;
  --blue-l:   #3B82F6;
  --blue-ll:  #DBEAFE;
  --navy:     #1E293B;
  --gray-d:   #475569;
  --gray:     #94A3B8;
  --gray-l:   #E2E8F0;
  --bg:       #F1F5F9;
  --white:    #FFFFFF;
  --orange:   #F97316;
  --red:      #EF4444;
  --green:    #22C55E;
  --radius:   12px;
  --shadow:   0 1px 3px rgba(0,0,0,.08), 0 4px 16px rgba(0,0,0,.06);
}

body {
  font-family: 'Noto Sans JP', 'Hiragino Sans', 'Yu Gothic UI', sans-serif;
  background: var(--bg);
  color: var(--navy);
  font-size: 15px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

/* ── Header ── */
.site-header {
  background: linear-gradient(135deg, #1d4ed8 0%, #2563EB 60%, #3B82F6 100%);
  padding: 48px 20px 40px;
  text-align: center;
  color: var(--white);
}
.site-header .label {
  display: inline-block;
  background: rgba(255,255,255,.18);
  border: 1px solid rgba(255,255,255,.3);
  border-radius: 999px;
  font-size: .72rem;
  font-weight: 700;
  letter-spacing: .08em;
  padding: 3px 12px;
  margin-bottom: 14px;
  text-transform: uppercase;
}
.site-header h1 {
  font-size: clamp(1.4rem, 4vw, 2rem);
  font-weight: 800;
  letter-spacing: -.02em;
  line-height: 1.3;
  margin-bottom: 10px;
}
.site-header p {
  font-size: .88rem;
  opacity: .85;
  max-width: 480px;
  margin: 0 auto;
}

/* ── Layout ── */
.container {
  max-width: 680px;
  margin: 0 auto;
  padding: 28px 16px 60px;
}

/* ── Card ── */
.card {
  background: var(--white);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px;
  margin-bottom: 16px;
}
.card-title {
  font-size: .78rem;
  font-weight: 700;
  color: var(--blue);
  letter-spacing: .06em;
  text-transform: uppercase;
  margin-bottom: 18px;
  display: flex;
  align-items: center;
  gap: 6px;
  font-family: inherit;
  line-height: inherit;
}
.card-title::before {
  content: '';
  display: inline-block;
  width: 3px;
  height: 14px;
  background: var(--blue);
  border-radius: 2px;
}

/* ── Form ── */
.field { margin-bottom: 18px; }
.field:last-of-type { margin-bottom: 0; }
.field label {
  display: block;
  font-size: .82rem;
  font-weight: 700;
  color: var(--gray-d);
  margin-bottom: 6px;
}
.field select, .field input[type=number] {
  width: 100%;
  padding: 11px 14px;
  border: 1.5px solid var(--gray-l);
  border-radius: 8px;
  font-size: .95rem;
  color: var(--navy);
  background: var(--white);
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%2394A3B8' stroke-width='1.5' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  transition: border-color .15s;
}
.field select:focus, .field input[type=number]:focus {
  outline: none;
  border-color: var(--blue);
  box-shadow: 0 0 0 3px rgba(37,99,235,.1);
}
.field input[type=number] { background-image: none; }
.field-hint {
  font-size: .75rem;
  color: var(--gray);
  margin-top: 5px;
}
.custom-input {
  display: none;
  margin-top: 8px;
}

/* ── Button ── */
.btn-calc {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  width: 100%;
  padding: 14px;
  background: var(--blue);
  color: var(--white);
  border: none;
  border-radius: 10px;
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  margin-top: 22px;
  transition: background .15s, transform .1s;
}
.btn-calc:hover { background: #1d4ed8; }
.btn-calc:active { transform: scale(.98); }
.btn-calc svg { flex-shrink: 0; }

/* ── Result ── */
#result-card {
  display: none;
  animation: fadeUp .25s ease;
}
#result-card.show { display: block; }
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(10px); }
  to   { opacity: 1; transform: translateY(0); }
}

.result-main {
  background: linear-gradient(135deg, #EFF6FF, #DBEAFE);
  border-radius: 10px;
  padding: 18px 20px;
  margin-bottom: 16px;
  border: 1px solid #BFDBFE;
}
.result-label {
  font-size: .72rem;
  font-weight: 700;
  color: var(--blue);
  letter-spacing: .06em;
  text-transform: uppercase;
  margin-bottom: 4px;
}
.result-value {
  font-size: 2.4rem;
  font-weight: 800;
  color: var(--blue);
  letter-spacing: -.02em;
  line-height: 1;
  margin-bottom: 6px;
}
.result-formula {
  font-size: .8rem;
  color: var(--gray-d);
}

.result-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-bottom: 14px;
}
.result-item {
  background: var(--bg);
  border-radius: 8px;
  padding: 12px 14px;
}
.result-item-label {
  font-size: .72rem;
  color: var(--gray);
  margin-bottom: 3px;
}
.result-item-value {
  font-size: 1rem;
  font-weight: 700;
  color: var(--navy);
}

/* ── Alerts ── */
.alert {
  border-radius: 8px;
  padding: 12px 14px;
  font-size: .82rem;
  margin-bottom: 10px;
  display: flex;
  gap: 8px;
  align-items: flex-start;
}
.alert-warn {
  background: #FFF7ED;
  border: 1px solid #FED7AA;
  color: #9A3412;
}
.alert-info {
  background: #F0FDF4;
  border: 1px solid #BBF7D0;
  color: #166534;
}
.alert-danger {
  background: #FFF1F2;
  border: 1px solid #FECDD3;
  color: #9F1239;
}
.alert-icon { flex-shrink: 0; font-size: 1rem; line-height: 1.4; }

/* ── Circuit SVG ── */
.diagram-wrap {
  background: var(--bg);
  border-radius: 10px;
  padding: 16px;
  margin-bottom: 14px;
  text-align: center;
}
.diagram-wrap svg { max-width: 100%; height: auto; }

/* ── E24 Grid ── */
.e24-details { margin-top: 4px; }
.e24-details summary {
  font-size: .78rem;
  color: var(--gray-d);
  cursor: pointer;
  user-select: none;
  padding: 6px 0;
}
.e24-grid {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 4px;
  margin-top: 10px;
}
.e24-grid span {
  text-align: center;
  padding: 5px 2px;
  font-size: .72rem;
  border-radius: 5px;
  background: var(--bg);
  color: var(--gray-d);
  border: 1px solid var(--gray-l);
}
.e24-grid span.hit {
  background: var(--blue);
  color: var(--white);
  border-color: var(--blue);
  font-weight: 700;
}

/* ── How to use ── */
.steps { counter-reset: step; display: flex; flex-direction: column; gap: 12px; }
.step {
  display: flex;
  gap: 14px;
  align-items: flex-start;
}
.step-num {
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  background: var(--blue);
  color: var(--white);
  border-radius: 50%;
  font-size: .78rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-top: 2px;
}
.step-text { font-size: .88rem; color: var(--gray-d); }
.step-text strong { color: var(--navy); }

/* ── Vf Table ── */
.vf-table { width: 100%; border-collapse: collapse; font-size: .82rem; margin-top: 8px; }
.vf-table th {
  background: var(--blue-ll);
  color: var(--blue);
  font-weight: 700;
  padding: 8px 12px;
  text-align: left;
  font-size: .75rem;
  letter-spacing: .04em;
}
.vf-table td { padding: 8px 12px; border-bottom: 1px solid var(--gray-l); }
.vf-table tr:last-child td { border-bottom: none; }
.vf-table tr:hover td { background: #F8FAFC; }
.dot {
  display: inline-block;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  margin-right: 6px;
  vertical-align: middle;
}

/* ── Breadcrumb ── */
.breadcrumb {
  font-size: .75rem;
  color: rgba(255,255,255,.7);
  padding: 10px 20px 0;
  max-width: 680px;
  margin: 0 auto;
}
.breadcrumb a { color: rgba(255,255,255,.7); text-decoration: none; }
.breadcrumb a:hover { color: var(--white); }
.breadcrumb span { margin: 0 5px; }

/* ── FAQ ── */
.faq-list { display: flex; flex-direction: column; gap: 0; }
.faq-item {
  border-bottom: 1px solid var(--gray-l);
}
.faq-item:last-child { border-bottom: none; }
.faq-item summary {
  font-size: .88rem;
  font-weight: 700;
  color: var(--navy);
  cursor: pointer;
  padding: 14px 0;
  user-select: none;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 8px;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: '+';
  font-size: 1.1rem;
  color: var(--blue);
  flex-shrink: 0;
  font-weight: 400;
}
.faq-item[open] summary::after { content: '−'; }
.faq-answer {
  font-size: .85rem;
  color: var(--gray-d);
  line-height: 1.7;
  padding-bottom: 14px;
}

/* ── Related ── */
.related-list { display: flex; flex-direction: column; gap: 10px; }
.related-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  background: var(--bg);
  border-radius: 10px;
  text-decoration: none;
  color: var(--navy);
  border: 1px solid var(--gray-l);
  transition: border-color .15s, box-shadow .15s;
}
.related-item:hover {
  border-color: var(--blue-l);
  box-shadow: 0 0 0 3px rgba(37,99,235,.08);
}
.related-icon {
  width: 36px;
  height: 36px;
  background: var(--blue-ll);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  color: var(--blue);
  font-size: 1rem;
}
.related-text { flex: 1; }
.related-title { font-size: .88rem; font-weight: 700; margin-bottom: 2px; }
.related-desc { font-size: .75rem; color: var(--gray); }
.related-arrow { color: var(--gray); font-size: .9rem; }

/* ── Footer ── */
.ad-wrap { margin: 0 0 16px; }

.site-footer {
  text-align: center;
  padding: 28px 16px;
  font-size: .75rem;
  color: var(--gray);
  border-top: 1px solid var(--gray-l);
  background: var(--white);
}
.site-footer a { color: var(--blue); text-decoration: none; }

@media (max-width: 480px) {
  .site-header { padding: 36px 16px 30px; }
  .card { padding: 18px; }
  .result-value { font-size: 2rem; }
  .result-row { grid-template-columns: 1fr; }
  .e24-grid { grid-template-columns: repeat(4, 1fr); }
}