/* ====================================================
   複線図ページ (futensen.css)
   電気試験勉強会 — Dark Navy × Amber テーマ継承
==================================================== */

/* ---- CSS Variables（メインサイトと共通） ---- */
:root {
  --color-primary:     #f59e0b;
  --color-primary-dark:#d97706;
  --color-accent:      #ef4444;
  --color-dark:        #0f172a;
  --color-dark-2:      #1e293b;
  --color-dark-3:      #334155;
  --color-light:       #f8fafc;
  --color-text:        #1e293b;
  --color-text-muted:  #64748b;
  --color-border:      #e2e8f0;
  --color-white:       #ffffff;

  --font-jp: 'Noto Sans JP', sans-serif;
  --font-en: 'Inter', sans-serif;
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --shadow-md: 0 4px 16px rgba(0,0,0,.12), 0 2px 6px rgba(0,0,0,.08);
  --shadow-lg: 0 10px 40px rgba(0,0,0,.18), 0 4px 12px rgba(0,0,0,.12);
  --transition: .3s cubic-bezier(.4,0,.2,1);
}

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

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

body {
  font-family: var(--font-jp);
  color: var(--color-text);
  background: var(--color-light);
  line-height: 1.7;
  overflow-x: hidden;
}

/* ---- ヘッダー ---- */
.fs-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-dark);
  border-bottom: 2px solid var(--color-primary);
  box-shadow: 0 2px 20px rgba(0,0,0,.4);
}
.fs-header-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
  height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
.fs-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}
.fs-logo-icon {
  width: 36px;
  height: 36px;
  background: var(--color-primary);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-dark);
  font-size: 1rem;
  font-weight: 900;
}
.fs-logo-text {
  font-size: .95rem;
  font-weight: 700;
  color: var(--color-white);
  letter-spacing: .03em;
}
.fs-nav {
  display: flex;
  align-items: center;
  gap: 16px;
}
.fs-nav-link {
  color: rgba(255,255,255,.75);
  text-decoration: none;
  font-size: .875rem;
  transition: color var(--transition);
  display: flex;
  align-items: center;
  gap: 6px;
}
.fs-nav-link:hover { color: var(--color-primary); }
.fs-nav-apply {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 8px 18px;
  background: var(--color-primary);
  color: var(--color-dark);
  font-size: .875rem;
  font-weight: 700;
  border-radius: 100px;
  text-decoration: none;
  transition: background var(--transition), transform var(--transition);
}
.fs-nav-apply:hover { background: var(--color-primary-dark); transform: translateY(-1px); }

/* ---- ヒーロー ---- */
.fs-hero {
  background: linear-gradient(135deg, var(--color-dark) 0%, #1e2d4a 60%, #0f2233 100%);
  padding: 80px 24px 72px;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.fs-hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at 30% 50%, rgba(245,158,11,.12) 0%, transparent 60%),
              radial-gradient(ellipse at 70% 30%, rgba(59,130,246,.08) 0%, transparent 50%);
  pointer-events: none;
}
.fs-hero-inner {
  position: relative;
  max-width: 700px;
  margin: 0 auto;
}
.fs-hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  background: rgba(245,158,11,.15);
  border: 1px solid rgba(245,158,11,.3);
  border-radius: 100px;
  color: var(--color-primary);
  font-size: .82rem;
  font-weight: 700;
  letter-spacing: .08em;
  margin-bottom: 22px;
}
.fs-hero-title {
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 900;
  color: var(--color-white);
  line-height: 1.2;
  margin-bottom: 20px;
  letter-spacing: -.01em;
}
.fs-hero-title em {
  font-style: normal;
  color: var(--color-primary);
}
.fs-hero-desc {
  color: rgba(255,255,255,.7);
  font-size: 1rem;
  margin-bottom: 28px;
  line-height: 1.8;
}
.fs-hero-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: center;
}
.fs-badge {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 6px 14px;
  background: rgba(255,255,255,.07);
  border: 1px solid rgba(255,255,255,.15);
  border-radius: 6px;
  color: rgba(255,255,255,.85);
  font-size: .8rem;
}
.fs-badge i { color: #4ade80; }

/* ---- 問題選択セクション ---- */
.fs-select-section {
  padding: 60px 24px 80px;
  background: var(--color-light);
}
.fs-container {
  max-width: 1060px;
  margin: 0 auto;
}
.fs-select-header {
  text-align: center;
  margin-bottom: 40px;
}
.fs-select-header h2 {
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--color-dark);
  margin-bottom: 8px;
}
.fs-select-header p {
  color: var(--color-text-muted);
  font-size: .95rem;
}

/* ---- 13問カードグリッド ---- */
.fs-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 16px;
}
.fs-problem-card {
  background: var(--color-white);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 22px 18px;
  cursor: pointer;
  transition: all var(--transition);
  text-align: center;
  position: relative;
  overflow: hidden;
}
.fs-problem-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: var(--color-primary);
  transform: scaleX(0);
  transition: transform var(--transition);
}
.fs-problem-card:hover {
  border-color: var(--color-primary);
  box-shadow: 0 8px 32px rgba(245,158,11,.18);
  transform: translateY(-4px);
}
.fs-problem-card:hover::before { transform: scaleX(1); }

.fs-card-num {
  font-size: 2rem;
  font-weight: 900;
  font-family: var(--font-en);
  color: var(--color-primary);
  line-height: 1;
  margin-bottom: 8px;
}
.fs-card-no-label {
  font-size: .65rem;
  font-weight: 700;
  color: var(--color-text-muted);
  letter-spacing: .1em;
  text-transform: uppercase;
  margin-bottom: 6px;
}
.fs-card-name {
  font-size: .82rem;
  font-weight: 600;
  color: var(--color-text);
  line-height: 1.5;
  margin-bottom: 12px;
}
.fs-card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  justify-content: center;
}
.fs-card-tag {
  font-size: .68rem;
  padding: 2px 8px;
  border-radius: 100px;
  background: #f1f5f9;
  color: var(--color-text-muted);
}
.fs-card-tag.tag-switch { background: #fef9c3; color: #854d0e; }
.fs-card-tag.tag-3wire  { background: #dbeafe; color: #1e40af; }
.fs-card-tag.tag-3way   { background: #ede9fe; color: #5b21b6; }
.fs-card-tag.tag-outlet { background: #dcfce7; color: #166534; }
.fs-card-tag.tag-pipe   { background: #fee2e2; color: #991b1b; }
.fs-card-tag.tag-joint  { background: #fce7f3; color: #9d174d; }

.fs-card-arrow {
  position: absolute;
  bottom: 12px;
  right: 14px;
  width: 28px;
  height: 28px;
  background: var(--color-primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-dark);
  font-size: .7rem;
  opacity: 0;
  transform: scale(.7);
  transition: all var(--transition);
}
.fs-problem-card:hover .fs-card-arrow {
  opacity: 1;
  transform: scale(1);
}

/* ---- モーダル ---- */
.fs-modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.75);
  backdrop-filter: blur(6px);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition);
}
.fs-modal-overlay.active {
  opacity: 1;
  pointer-events: all;
}
.fs-modal {
  background: var(--color-white);
  border-radius: var(--radius-lg);
  width: 100%;
  max-width: 840px;
  max-height: 92vh;
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
  transform: scale(.95) translateY(20px);
  transition: transform var(--transition);
  position: relative;
}
.fs-modal-overlay.active .fs-modal {
  transform: scale(1) translateY(0);
}
.fs-modal-close {
  position: sticky;
  top: 0;
  float: right;
  margin: 16px 16px 0 0;
  width: 36px;
  height: 36px;
  background: #f1f5f9;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  font-size: 1rem;
  color: var(--color-text-muted);
  z-index: 10;
  transition: all var(--transition);
  display: flex;
  align-items: center;
  justify-content: center;
}
.fs-modal-close:hover { background: var(--color-accent); color: white; }

.fs-modal-header {
  display: flex;
  align-items: center;
  gap: 18px;
  padding: 24px 28px 20px;
  border-bottom: 2px solid var(--color-border);
}
.fs-modal-num {
  width: 60px;
  height: 60px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  font-weight: 900;
  font-family: var(--font-en);
  color: var(--color-dark);
  flex-shrink: 0;
}
.fs-modal-title {
  font-size: 1.3rem;
  font-weight: 800;
  color: var(--color-dark);
  margin-bottom: 4px;
}
.fs-modal-subtitle {
  font-size: .85rem;
  color: var(--color-text-muted);
}

/* ---- タブ ---- */
.fs-tabs {
  display: flex;
  gap: 0;
  padding: 16px 28px 0;
  border-bottom: 2px solid var(--color-border);
}
.fs-tab {
  padding: 10px 20px;
  border: none;
  background: none;
  cursor: pointer;
  font-family: var(--font-jp);
  font-size: .875rem;
  font-weight: 600;
  color: var(--color-text-muted);
  border-bottom: 3px solid transparent;
  margin-bottom: -2px;
  display: flex;
  align-items: center;
  gap: 7px;
  transition: all var(--transition);
}
.fs-tab:hover { color: var(--color-primary); }
.fs-tab.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

/* ---- タブコンテンツ ---- */
.fs-tab-content {
  display: none;
  padding: 24px 28px;
}
.fs-tab-content.active { display: block; }

/* ---- 複線図エリア ---- */
.fs-diagram-wrap {
  text-align: center;
}
#diagramCanvas {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  background: #f8fafc;
  border: 2px solid var(--color-border);
  display: block;
  margin: 0 auto 16px;
}
.fs-diagram-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  justify-content: center;
  font-size: .8rem;
  color: var(--color-text-muted);
}
.legend-item {
  display: flex;
  align-items: center;
  gap: 7px;
}
.legend-line {
  display: inline-block;
  width: 32px;
  height: 4px;
  border-radius: 2px;
}
.legend-black { background: #1e293b; }
.legend-white { background: #94a3b8; border: 1px solid #cbd5e1; }
.legend-red   { background: #ef4444; }
.legend-green { background: #22c55e; }

/* ---- ステップ解説 ---- */
.fs-steps-wrap {
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.fs-step {
  display: flex;
  gap: 16px;
  align-items: flex-start;
}
.fs-step-num {
  flex-shrink: 0;
  width: 36px;
  height: 36px;
  background: var(--color-primary);
  color: var(--color-dark);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 900;
  font-size: .95rem;
  margin-top: 2px;
}
.fs-step-body h4 {
  font-size: .95rem;
  font-weight: 700;
  color: var(--color-dark);
  margin-bottom: 4px;
}
.fs-step-body p {
  font-size: .875rem;
  color: var(--color-text-muted);
  line-height: 1.7;
}
.fs-step-body .step-wire {
  display: inline-block;
  padding: 1px 8px;
  border-radius: 4px;
  font-size: .78rem;
  font-weight: 700;
  margin: 0 3px;
}
.step-wire-black { background: #1e293b; color: white; }
.step-wire-white { background: #e2e8f0; color: #334155; }
.step-wire-red   { background: #fef2f2; color: #dc2626; border: 1px solid #fca5a5; }
.step-wire-green { background: #f0fdf4; color: #16a34a; border: 1px solid #86efac; }

/* ---- 注意ポイント ---- */
.fs-points-wrap {
  display: flex;
  flex-direction: column;
  gap: 14px;
}
.fs-point {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  padding: 16px 18px;
  border-radius: var(--radius-md);
  border-left: 4px solid;
}
.fs-point--warn {
  background: #fffbeb;
  border-color: #f59e0b;
}
.fs-point--danger {
  background: #fef2f2;
  border-color: #ef4444;
}
.fs-point--info {
  background: #eff6ff;
  border-color: #3b82f6;
}
.fs-point-icon {
  font-size: 1.1rem;
  flex-shrink: 0;
  margin-top: 1px;
}
.fs-point--warn .fs-point-icon  { color: #f59e0b; }
.fs-point--danger .fs-point-icon { color: #ef4444; }
.fs-point--info .fs-point-icon  { color: #3b82f6; }
.fs-point-body h4 {
  font-size: .9rem;
  font-weight: 700;
  color: var(--color-dark);
  margin-bottom: 3px;
}
.fs-point-body p {
  font-size: .845rem;
  color: var(--color-text-muted);
  line-height: 1.65;
}

/* ---- モーダルフッター ---- */
.fs-modal-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 16px 28px 24px;
  border-top: 2px solid var(--color-border);
}
.fs-btn-prev,
.fs-btn-next {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  border: 2px solid var(--color-border);
  background: var(--color-white);
  border-radius: 100px;
  font-family: var(--font-jp);
  font-size: .875rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
  color: var(--color-text);
}
.fs-btn-prev:hover,
.fs-btn-next:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}
.fs-btn-prev:disabled,
.fs-btn-next:disabled {
  opacity: .3;
  cursor: not-allowed;
}
.fs-btn-apply {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  background: var(--color-primary);
  color: var(--color-dark);
  font-weight: 700;
  border-radius: 100px;
  text-decoration: none;
  font-size: .875rem;
  transition: all var(--transition);
}
.fs-btn-apply:hover { background: var(--color-primary-dark); transform: translateY(-1px); }

/* ---- Tips セクション ---- */
.fs-tips-section {
  background: var(--color-dark);
  padding: 64px 24px;
}
.fs-tips-title {
  text-align: center;
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--color-white);
  margin-bottom: 36px;
}
.fs-tips-title i { color: var(--color-primary); margin-right: 10px; }
.fs-tips-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  max-width: 900px;
  margin: 0 auto;
}
.fs-tip-card {
  background: rgba(255,255,255,.05);
  border: 1px solid rgba(255,255,255,.1);
  border-radius: var(--radius-md);
  padding: 28px 22px;
}
.fs-tip-num {
  font-size: 2.5rem;
  font-weight: 900;
  font-family: var(--font-en);
  color: var(--color-primary);
  opacity: .5;
  line-height: 1;
  margin-bottom: 12px;
}
.fs-tip-card h3 {
  font-size: .95rem;
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 10px;
}
.fs-tip-card p {
  font-size: .845rem;
  color: rgba(255,255,255,.55);
  line-height: 1.75;
}

/* ---- CTAセクション ---- */
.fs-cta-section {
  padding: 64px 24px;
  background: var(--color-light);
}
.fs-cta-box {
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
  background: var(--color-white);
  border: 2px solid var(--color-primary);
  border-radius: var(--radius-lg);
  padding: 48px 36px;
  box-shadow: 0 0 60px rgba(245,158,11,.12);
}
.fs-cta-icon {
  width: 64px;
  height: 64px;
  background: var(--color-primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  color: var(--color-dark);
  margin: 0 auto 20px;
}
.fs-cta-box h2 {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--color-dark);
  margin-bottom: 12px;
}
.fs-cta-box p {
  font-size: .9rem;
  color: var(--color-text-muted);
  margin-bottom: 28px;
  line-height: 1.8;
}
.fs-cta-btn {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 16px 36px;
  background: var(--color-primary);
  color: var(--color-dark);
  font-weight: 800;
  font-size: 1.05rem;
  border-radius: 100px;
  text-decoration: none;
  transition: all var(--transition);
  margin-bottom: 16px;
  box-shadow: 0 4px 20px rgba(245,158,11,.4);
}
.fs-cta-btn:hover { background: var(--color-primary-dark); transform: translateY(-2px); }
.fs-cta-sub {
  display: block;
  color: var(--color-text-muted);
  font-size: .875rem;
  text-decoration: none;
  transition: color var(--transition);
}
.fs-cta-sub:hover { color: var(--color-primary); }

/* ---- フッター ---- */
.fs-footer {
  background: #070e1c;
  padding: 24px;
  text-align: center;
}
.fs-footer p {
  font-size: .8rem;
  color: rgba(255,255,255,.35);
  margin-bottom: 10px;
}
.fs-footer-nav {
  display: flex;
  gap: 20px;
  justify-content: center;
}
.fs-footer-nav a {
  color: rgba(255,255,255,.4);
  text-decoration: none;
  font-size: .8rem;
  transition: color var(--transition);
}
.fs-footer-nav a:hover { color: var(--color-primary); }

/* ---- レスポンシブ ---- */
@media (max-width: 768px) {
  .fs-hero { padding: 56px 20px 52px; }
  .fs-modal-header { padding: 20px 20px 16px; flex-wrap: wrap; }
  .fs-tabs { padding: 12px 16px 0; overflow-x: auto; }
  .fs-tab { padding: 10px 14px; white-space: nowrap; font-size: .8rem; }
  .fs-tab-content { padding: 20px 16px; }
  .fs-modal-footer { flex-wrap: wrap; padding: 16px 16px 20px; }
  .fs-btn-apply { order: -1; width: 100%; justify-content: center; }
  .fs-tips-grid { grid-template-columns: 1fr; }
  .fs-cta-box { padding: 36px 20px; }
  .fs-modal-num { width: 48px; height: 48px; font-size: 1rem; }
  .fs-modal-title { font-size: 1.1rem; }
  .fs-diagram-legend { gap: 10px; font-size: .75rem; }
}
@media (max-width: 480px) {
  .fs-grid { grid-template-columns: repeat(3, 1fr); gap: 10px; }
  .fs-problem-card { padding: 14px 10px; }
  .fs-card-num { font-size: 1.5rem; }
  .fs-card-name { font-size: .73rem; }
  .fs-card-tags { display: none; }
  .fs-nav-link { display: none; }
}
@media (max-width: 360px) {
  .fs-grid { grid-template-columns: repeat(2, 1fr); }
}