* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Yu Gothic", system-ui, sans-serif;
  line-height: 1.7;
  color: #111111;
  background: #f5f0e6; /* 暖かみのある紙色 */
}

img {
  max-width: 100%;
  height: auto;
}

a {
  color: #1e73be;
  text-decoration: none;
}

a:hover,
a:focus {
  text-decoration: underline;
}

a:focus-visible {
  outline: 2px solid #b00020;
  outline-offset: 2px;
}

.site-header {
  border-bottom: 1px solid rgba(0, 0, 0, 0.08);
  background: #ffffff;
}

.site-header-inner {
  max-width: 1040px;
  margin: 0 auto;
  padding: 18px 20px 10px;
}

.brand-block {
  margin-bottom: 10px;
}

.brand-title {
  font-size: 1.4rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.brand-subtitle {
  font-size: 0.9rem;
  color: #555;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 18px;
  font-size: 0.85rem;
  margin-top: 6px;
}

.site-nav a {
  padding-bottom: 2px;
  border-bottom: 1px solid transparent;
}

.site-nav a:hover {
  border-color: #1e73be;
}

.site-main {
  max-width: 1040px;
  margin: 0 auto;
  padding: 30px 20px 60px;
}

.section {
  padding: 26px 0;
  border-top: 1px solid rgba(0, 0, 0, 0.06);
}

.section-intro {
  border-top: none;
}

.section h1,
.section h2,
.section h3 {
  font-weight: 600;
  letter-spacing: 0.03em;
}

.section h1 {
  font-size: 1.7rem;
  margin: 10px 0 18px;
}

.section h2 {
  font-size: 1.3rem;
  margin: 0 0 14px;
}

.section h3 {
  font-size: 1.05rem;
  margin: 18px 0 10px;
}

.note {
  font-size: 0.8rem;
  color: #555;
}

.meta {
  font-size: 0.8rem;
  color: #777;
  margin-top: 4px;
}

.marker {
  background: linear-gradient(transparent 60%, #e5f3ff 60%);
}

.index-list {
  padding-left: 1.2em;
  margin: 0;
}

.index-list li {
  margin-bottom: 4px;
}

.bullet-list {
  list-style: disc;
  padding-left: 1.3em;
}

.bullet-list li {
  margin-bottom: 4px;
}

.table-scroll {
  overflow-x: auto;
  margin: 10px 0 4px;
}

.compare-table,
.plan-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
  background: #ffffff;
}

.compare-table th,
.compare-table td,
.plan-table th,
.plan-table td {
  padding: 8px 10px;
  border: 1px solid rgba(0, 0, 0, 0.08);
  vertical-align: top;
}

.compare-table thead th,
.plan-table thead th {
  background: #e5f3ff;
  font-weight: 600;
}

.carrier-block + .carrier-block {
  margin-top: 28px;
}

.speed-note {
  font-size: 0.85rem;
  color: #555;
}

.faq-item {
  border: 1px solid rgba(0, 0, 0, 0.1);
  background: #ffffff;
  padding: 8px 12px;
  margin-bottom: 8px;
}

.faq-item summary {
  cursor: pointer;
  font-weight: 500;
}

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

.faq-item summary::before {
  content: "＋";
  margin-right: 6px;
  color: #1e73be;
}

.faq-item[open] summary::before {
  content: "−";
}

.faq-item p {
  margin-top: 6px;
  font-size: 0.9rem;
}

.site-footer {
  border-top: 1px solid rgba(0, 0, 0, 0.1);
  background: #111111;
  color: #f5f5f5;
}

.footer-inner {
  max-width: 1040px;
  margin: 0 auto;
  padding: 18px 20px 22px;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px 20px;
  font-size: 0.8rem;
}

.footer-copy a {
  color: #f5f5f5;
  border-bottom: 1px solid rgba(245, 245, 245, 0.4);
}

.footer-copy a:hover {
  border-color: #ffffff;
}

@media (max-width: 720px) {
  .section h1 {
    font-size: 1.4rem;
  }

  .site-main {
    padding: 20px 16px 40px;
  }

  .site-header-inner {
    padding: 14px 16px 8px;
  }

  .site-nav {
    gap: 6px 12px;
  }
}