:root {
  --primary: #17bbef;
  --primary-dark: #0fa3d4;
  --primary-light: #e8f8fd;
  --white: #ffffff;
  --black: #000000;
  --text-dark: #333333;
  --text-medium: #555555;
  --text-light: #777777;
  --bg-light: #f8f9fa;
  --bg-dark: #1a1a2e;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.12);
  --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.16);
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --transition: all 0.3s ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Noto Sans JP', sans-serif;
  color: var(--text-dark);
  background: var(--white);
  line-height: 1.75;
}

a {
  color: inherit;
  text-decoration: none;
}

img, svg {
  max-width: 100%;
  display: block;
}

.container {
  width: min(1100px, calc(100% - 48px));
  margin: 0 auto;
}

.section-padding {
  padding: 88px 0;
}

.section-title {
  font-size: clamp(1.8rem, 4vw, 2.7rem);
  line-height: 1.25;
  font-weight: 800;
  margin-bottom: 14px;
}

.section-subtitle {
  color: var(--text-medium);
  max-width: 760px;
}

.accent-line {
  width: 56px;
  height: 4px;
  border-radius: 999px;
  background: var(--primary);
  margin: 18px 0 0;
}

.kicker {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 14px;
  background: rgba(255,255,255,0.18);
  border: 1px solid rgba(255,255,255,0.34);
  border-radius: 999px;
  color: var(--white);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.muted-kicker {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 14px;
  background: var(--primary-light);
  border-radius: 999px;
  color: var(--primary-dark);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.04em;
}

#header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: 16px 0;
  transition: background 0.35s ease, box-shadow 0.35s ease, padding 0.35s ease;
}

#header.scrolled {
  background: rgba(255,255,255,0.97);
  box-shadow: var(--shadow-sm);
  padding: 10px 0;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.logo {
  display: flex;
  flex-direction: column;
  color: var(--white);
  font-weight: 900;
  line-height: 1.15;
  letter-spacing: 0.02em;
  transition: var(--transition);
}

.logo span {
  font-size: 0.72rem;
  font-weight: 500;
  opacity: 0.88;
  letter-spacing: 0.08em;
  margin-top: 3px;
}

#header.scrolled .logo {
  color: var(--primary);
}

.nav-links {
  list-style: none;
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-links a {
  position: relative;
  color: rgba(255,255,255,0.92);
  font-size: 0.93rem;
  font-weight: 600;
  transition: var(--transition);
}

.nav-links a::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -5px;
  width: 0;
  height: 2px;
  border-radius: 999px;
  background: var(--white);
  transition: width 0.3s ease;
}

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

#header.scrolled .nav-links a {
  color: var(--text-dark);
}

#header.scrolled .nav-links a::after {
  background: var(--primary);
}

.nav-cta {
  padding: 10px 18px;
  border: 1px solid rgba(255,255,255,0.85);
  border-radius: 999px;
}

#header.scrolled .nav-cta {
  background: var(--primary);
  border-color: var(--primary);
  color: var(--white);
}

.hamburger {
  display: none;
  width: 44px;
  height: 44px;
  border: 0;
  background: transparent;
  cursor: pointer;
}

.hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  margin: 5px auto;
  background: var(--white);
  transition: var(--transition);
}

#header.scrolled .hamburger span {
  background: var(--text-dark);
}

.mobile-nav {
  position: fixed;
  inset: 0;
  background: rgba(23, 187, 239, 0.98);
  backdrop-filter: blur(10px);
  z-index: 1001;
  display: none;
  padding: 100px 24px 60px;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
}

.mobile-nav.open {
  display: block;
}

.mobile-nav ul {
  list-style: none;
  display: grid;
  gap: 12px;
}

.mobile-nav a {
  display: block;
  color: var(--white);
  font-size: 1rem;
  font-weight: 700;
  padding: 14px 18px;
  border-radius: var(--radius-md);
  background: rgba(255,255,255,0.1);
  text-align: center;
}

.page-hero {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, #0d9fd4 0%, #17bbef 55%, #4ecef5 100%);
  color: var(--white);
  padding: 150px 0 80px;
}

.page-hero::before,
.page-hero::after {
  content: '';
  position: absolute;
  border-radius: 50%;
  background: rgba(255,255,255,0.12);
  filter: blur(2px);
}

.page-hero::before {
  width: 320px;
  height: 320px;
  right: -80px;
  top: 20px;
}

.page-hero::after {
  width: 220px;
  height: 220px;
  left: -70px;
  bottom: -40px;
}

.hero-grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 42px;
  align-items: center;
}

.hero-copy h1 {
  font-size: clamp(2rem, 4.5vw, 3.6rem);
  line-height: 1.2;
  margin: 18px 0 18px;
  font-weight: 900;
}

.hero-copy p {
  font-size: 1.04rem;
  opacity: 0.94;
  max-width: 680px;
}

.hero-meta,
.post-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.meta-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 14px;
  border-radius: 999px;
  background: rgba(255,255,255,0.16);
  border: 1px solid rgba(255,255,255,0.24);
  font-size: 0.92rem;
}

.hero-visual,
.card-visual,
.article-visual {
  background: rgba(255,255,255,0.12);
  border: 1px solid rgba(255,255,255,0.22);
  border-radius: 28px;
  padding: 18px;
  backdrop-filter: blur(8px);
  box-shadow: 0 16px 40px rgba(0,0,0,0.12);
}

.hero-visual svg,
.article-visual svg {
  width: 100%;
  height: auto;
}

.blog-intro {
  background: var(--white);
}

.chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  border-radius: 999px;
  background: var(--primary-light);
  color: var(--primary-dark);
  font-weight: 700;
  font-size: 0.88rem;
  padding: 10px 14px;
}

.feature-grid,
.blog-grid,
.related-grid,
.summary-grid {
  display: grid;
  gap: 24px;
}

.feature-grid {
  grid-template-columns: repeat(3, 1fr);
  margin-top: 34px;
}

.blog-grid,
.related-grid {
  grid-template-columns: repeat(3, 1fr);
}

.feature-card,
.blog-card,
.related-card,
.summary-card,
.side-card,
.cta-panel,
.author-card,
.note-box,
.check-card,
.table-card,
.timeline-card {
  background: var(--white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
}

.feature-card,
.blog-card,
.related-card,
.summary-card {
  overflow: hidden;
  border: 1px solid #eef3f6;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-card:hover,
.blog-card:hover,
.related-card:hover,
.summary-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-md);
}

.card-visual {
  background: linear-gradient(135deg, rgba(13,159,212,0.96), rgba(23,187,239,0.86));
  border: 0;
  border-bottom-left-radius: 0;
  border-bottom-right-radius: 0;
  box-shadow: none;
}

.card-body {
  padding: 26px 24px 24px;
}

.card-body h3 {
  font-size: 1.18rem;
  line-height: 1.45;
  margin: 10px 0 12px;
}

.card-body p {
  color: var(--text-medium);
  font-size: 0.95rem;
}

.card-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  color: var(--text-light);
  font-size: 0.84rem;
  margin-bottom: 10px;
}

.read-more {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-top: 18px;
  color: var(--primary-dark);
  font-weight: 700;
}

.section-soft {
  background: var(--bg-light);
}

.article-shell {
  padding-top: 42px;
}

.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  font-size: 0.9rem;
  opacity: 0.9;
}

.article-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.55fr) minmax(280px, 0.75fr);
  gap: 32px;
  align-items: start;
}

.article-main {
  background: var(--white);
  border-radius: 28px;
  padding: 36px;
  box-shadow: var(--shadow-sm);
  border: 1px solid #eef3f6;
}

.article-main > * + * {
  margin-top: 22px;
}

.article-main h2 {
  font-size: 1.55rem;
  line-height: 1.35;
  margin-top: 36px;
}

.article-main h3 {
  font-size: 1.15rem;
  line-height: 1.45;
  margin-top: 24px;
}

.article-main p,
.article-main li {
  color: var(--text-medium);
}

.article-main ul,
.article-main ol {
  padding-left: 1.2em;
}

.lead-box {
  padding: 22px 24px;
  background: linear-gradient(180deg, rgba(23,187,239,0.08), rgba(23,187,239,0.03));
  border-left: 4px solid var(--primary);
  border-radius: var(--radius-md);
}

.note-box,
.check-card,
.table-card,
.timeline-card,
.cta-panel,
.author-card,
.side-card {
  padding: 24px;
  border: 1px solid #eef3f6;
}

.note-box {
  background: var(--primary-light);
}

.note-box strong,
.check-card strong,
.side-card strong {
  color: var(--text-dark);
}

.check-list,
.side-list,
.mini-list,
.timeline-list {
  display: grid;
  gap: 12px;
  list-style: none;
  padding-left: 0;
}

.check-list li,
.side-list li,
.mini-list li,
.timeline-list li {
  display: flex;
  gap: 10px;
  align-items: flex-start;
}

.check-list i,
.side-list i,
.mini-list i,
.timeline-list i {
  color: var(--primary);
  margin-top: 4px;
}

.table-card table {
  width: 100%;
  border-collapse: collapse;
}

.table-card th,
.table-card td {
  text-align: left;
  padding: 14px 0;
  border-bottom: 1px solid #edf2f5;
  vertical-align: top;
}

.table-card th {
  width: 28%;
  color: var(--text-dark);
}

.article-sidebar {
  display: grid;
  gap: 18px;
  position: sticky;
  top: 100px;
}

.side-card h3,
.author-card h3,
.cta-panel h3,
.summary-card h3 {
  font-size: 1.08rem;
  margin-bottom: 14px;
}

.side-card p,
.author-card p,
.cta-panel p,
.summary-card p {
  color: var(--text-medium);
}

.cta-panel {
  background: linear-gradient(135deg, rgba(13,159,212,1), rgba(23,187,239,0.92));
  color: var(--white);
}

.cta-panel p,
.cta-panel .side-list li {
  color: rgba(255,255,255,0.95);
}

.button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 18px;
}

.btn-primary,
.btn-secondary,
.btn-ghost {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 48px;
  padding: 0 22px;
  border-radius: 999px;
  font-weight: 700;
  transition: var(--transition);
}

.btn-primary {
  background: var(--white);
  color: var(--primary);
  border: 2px solid var(--white);
}

.btn-primary:hover {
  transform: translateY(-2px);
  background: transparent;
  color: var(--white);
}

.btn-secondary {
  background: var(--primary);
  color: var(--white);
  border: 2px solid var(--primary);
}

.btn-secondary:hover {
  transform: translateY(-2px);
  background: var(--primary-dark);
  border-color: var(--primary-dark);
}

.btn-ghost {
  background: transparent;
  border: 2px solid rgba(255,255,255,0.45);
  color: var(--white);
}

.btn-ghost.dark {
  color: var(--primary-dark);
  border-color: rgba(23,187,239,0.35);
}

.summary-grid {
  grid-template-columns: repeat(3, 1fr);
  margin-top: 30px;
}

.summary-card {
  padding: 24px;
}

.summary-card i {
  font-size: 1.4rem;
  color: var(--primary);
  margin-bottom: 10px;
}

.author-card {
  display: grid;
  grid-template-columns: 64px 1fr;
  gap: 16px;
  align-items: start;
}

.author-badge {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: var(--white);
  display: grid;
  place-items: center;
  font-size: 1.3rem;
  font-weight: 800;
}

.related-section {
  padding: 72px 0 88px;
}

#footer {
  background: var(--bg-dark);
  color: rgba(255,255,255,0.78);
  padding: 56px 0 28px;
}

.footer-inner {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 36px;
  margin-bottom: 32px;
}

.footer-title {
  color: var(--white);
  font-size: 1.12rem;
  font-weight: 800;
  margin-bottom: 14px;
}

.footer-note {
  margin-top: 14px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(255,255,255,0.08);
  padding: 8px 14px;
  border-radius: 999px;
}

.footer-list {
  list-style: none;
  display: grid;
  gap: 10px;
}

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 20px;
  display: flex;
  justify-content: space-between;
  gap: 18px;
  flex-wrap: wrap;
  font-size: 0.92rem;
}

.credit-note {
  margin-top: 18px;
  color: var(--text-light);
  font-size: 0.9rem;
}

@media (max-width: 980px) {
  .hero-grid,
  .article-layout,
  .feature-grid,
  .blog-grid,
  .related-grid,
  .summary-grid,
  .footer-inner {
    grid-template-columns: 1fr;
  }

  .article-sidebar {
    position: static;
  }
}

@media (max-width: 820px) {
  .nav-links {
    display: none;
  }

  .hamburger {
    display: block;
  }

  .page-hero {
    padding-top: 128px;
    padding-bottom: 70px;
  }
}

@media (max-width: 640px) {
  .container {
    width: min(100%, calc(100% - 32px));
  }

  .section-padding {
    padding: 68px 0;
  }

  .article-main {
    padding: 24px 18px;
    border-radius: 22px;
  }

  .table-card th,
  .table-card td {
    display: block;
    width: 100%;
  }

  .footer-bottom {
    justify-content: center;
    text-align: center;
  }
}