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

/* === CSS Variables === */
:root {
  --bg: #f0f4f8;
  --surface: #ffffff;
  --surface2: #f8fafc;
  --border: #e2e8f0;
  --text: #0f172a;
  --text-muted: #64748b;
  --text-subtle: #94a3b8;
  --accent: #3AA8E8;
  --accent-dark: #2890d0;
  --accent-light: #e0f2fe;
  --success: #16a34a;
  --danger: #dc2626;
  --shadow: 0 1px 4px rgba(0,0,0,0.06), 0 2px 8px rgba(0,0,0,0.04);
  --radius: 12px;
  --radius-sm: 8px;
  --radius-full: 9999px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0a0f1a;
    --surface: #111827;
    --surface2: #1c2535;
    --border: #2d3f55;
    --text: #f1f5f9;
    --text-muted: #8ba3c7;
    --text-subtle: #4a6280;
    --accent: #4db8ef;
    --accent-dark: #3AA8E8;
    --accent-light: #0c2a3d;
    --success: #34d399;
    --danger: #f87171;
    --shadow: 0 1px 4px rgba(0,0,0,0.4), 0 2px 8px rgba(0,0,0,0.3);
  }
}

/* === Base === */
html { font-size: 16px; scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans",
    "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  -webkit-text-size-adjust: 100%;
  display: flex;
  flex-direction: column;
}

/* === Site Header === */
.site-header {
  background: var(--accent);
  padding: 0 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.15);
  position: sticky;
  top: 0;
  z-index: 100;
  flex-shrink: 0;
}

.site-brand {
  font-size: 20px;
  font-weight: 800;
  color: white;
  text-decoration: none;
  letter-spacing: 0.5px;
}

.header-home {
  font-size: 13px;
  color: rgba(255,255,255,0.88);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 6px 12px;
  border-radius: var(--radius-full);
  border: 1px solid rgba(255,255,255,0.3);
  transition: background 0.15s;
  -webkit-tap-highlight-color: transparent;
}

.header-home:hover { background: rgba(255,255,255,0.15); }

/* === Main Content === */
.page-main {
  flex: 1;
  padding: 32px 16px 64px;
}

.page-container {
  max-width: 700px;
  margin: 0 auto;
}

/* === Breadcrumb === */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  color: var(--text-subtle);
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.breadcrumb a {
  color: var(--accent);
  text-decoration: none;
}

.breadcrumb-sep { color: var(--text-subtle); }

/* === Page Header === */
.page-header { margin-bottom: 28px; }

.page-title {
  font-size: 28px;
  font-weight: 800;
  color: var(--text);
  letter-spacing: -0.5px;
  line-height: 1.3;
  margin-bottom: 8px;
}

.page-lead {
  font-size: 15px;
  color: var(--text-muted);
  line-height: 1.7;
}

/* === Article Card === */
.article {
  background: var(--surface);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  padding: 28px 24px;
  box-shadow: var(--shadow);
  margin-bottom: 16px;
}

@media (max-width: 480px) {
  .article { padding: 20px 16px; }
}

.article h2 {
  font-size: 17px;
  font-weight: 700;
  color: var(--text);
  margin: 32px 0 10px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--border);
}

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

.article h3 {
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
  margin: 20px 0 8px;
}

.article p {
  font-size: 15px;
  color: var(--text-muted);
  line-height: 1.85;
  margin-bottom: 14px;
}

.article p:last-child { margin-bottom: 0; }

.article ul, .article ol {
  font-size: 15px;
  color: var(--text-muted);
  line-height: 1.85;
  padding-left: 22px;
  margin-bottom: 14px;
}

.article li { margin-bottom: 6px; }

.article a {
  color: var(--accent);
  text-decoration: none;
}

.article a:hover { text-decoration: underline; }

.article .note {
  background: var(--accent-light);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 12px 16px;
  font-size: 14px;
  color: var(--text-muted);
  margin: 16px 0;
}

/* === Info Cards (guide/faq) === */
.info-card {
  background: var(--surface);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  padding: 24px;
  margin-bottom: 14px;
  box-shadow: var(--shadow);
}

.info-card-title {
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--accent);
  color: white;
  font-size: 11px;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: var(--radius-full);
  flex-shrink: 0;
}

.badge-q {
  background: var(--accent);
}

.step-list {
  list-style: none;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.step-item {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.7;
}

.step-num {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  min-width: 24px;
  background: var(--accent);
  color: white;
  border-radius: 50%;
  font-size: 12px;
  font-weight: 700;
  margin-top: 1px;
}

/* === FAQ accordion === */
details.faq-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  margin-bottom: 8px;
  overflow: hidden;
  box-shadow: var(--shadow);
}

details.faq-item summary {
  padding: 16px 20px;
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  cursor: pointer;
  user-select: none;
  list-style: none;
  display: flex;
  align-items: flex-start;
  gap: 10px;
  -webkit-tap-highlight-color: transparent;
}

details.faq-item summary::marker,
details.faq-item summary::-webkit-details-marker { display: none; }

details.faq-item summary .q-icon {
  flex-shrink: 0;
  width: 22px;
  height: 22px;
  background: var(--accent);
  color: white;
  border-radius: 50%;
  font-size: 12px;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-top: 1px;
}

.faq-answer {
  padding: 0 20px 16px 52px;
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.8;
  border-top: 1px solid var(--border);
  padding-top: 12px;
}

/* === Contact Form === */
.form-group {
  margin-bottom: 18px;
}

.form-label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
  margin-bottom: 6px;
  text-transform: uppercase;
  letter-spacing: 0.4px;
}

.form-control {
  width: 100%;
  padding: 12px 14px;
  font-size: 15px;
  font-family: inherit;
  color: var(--text);
  background: var(--surface2);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  outline: none;
  transition: border-color 0.15s;
  -webkit-appearance: none;
  appearance: none;
}

.form-control:focus {
  border-color: var(--accent);
}

textarea.form-control {
  min-height: 140px;
  resize: vertical;
}

.btn-submit {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  padding: 15px;
  font-size: 16px;
  font-weight: 700;
  background: var(--accent);
  color: white;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-family: inherit;
  min-height: 54px;
  transition: background 0.15s, transform 0.1s;
  -webkit-tap-highlight-color: transparent;
}

.btn-submit:hover { background: var(--accent-dark); }
.btn-submit:active { transform: scale(0.98); }

.form-note {
  font-size: 13px;
  color: var(--text-subtle);
  margin-top: 14px;
  line-height: 1.7;
  text-align: center;
}

/* === Site Footer === */
.site-footer {
  text-align: center;
  padding: 24px 16px;
  border-top: 1px solid var(--border);
  font-size: 13px;
  color: var(--text-subtle);
  flex-shrink: 0;
}

.site-footer p { margin-bottom: 12px; }

.footer-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 4px 16px;
  margin-bottom: 10px;
}

.footer-nav a {
  color: var(--accent);
  text-decoration: none;
  font-size: 13px;
}

.footer-nav a:hover { text-decoration: underline; }

.section-heading {
  font-size: 20px;
  font-weight: 700;
  color: var(--text);
  margin: 32px 0 12px;
  padding-bottom: 6px;
  border-bottom: 2px solid var(--border);
}

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