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

    :root {
      --ink: #0f172a;
      --ink-soft: #334155;
      --ink-muted: #64748b;
      --bg: #f6f8fb;
      --surface: #ffffff;
      --surface-soft: #eff6ff;
      --border: #dbe3ee;
      --accent: #0369a1;
      --accent-bright: #0ea5e9;
      --accent-pale: #e0f2fe;
      --hero: #071525;
      --hero-soft: #102a43;
      --focus: #f59e0b;
      --shadow: 0 18px 45px rgba(15, 23, 42, 0.08);
    }

    html {
      scroll-behavior: smooth;
    }

    body {
      margin: 0;
      background: var(--bg);
      color: var(--ink);
      font-family: "Noto Sans JP", sans-serif;
      font-size: 16px;
      line-height: 1.75;
    }

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

    button,
    input {
      font: inherit;
    }

    .skip-link {
      position: fixed;
      top: 0.5rem;
      left: 0.5rem;
      z-index: 999;
      padding: 0.65rem 1rem;
      background: var(--surface);
      color: var(--ink);
      border-radius: 0.4rem;
      transform: translateY(-150%);
    }

    .skip-link:focus {
      transform: translateY(0);
    }

    .site-header {
      position: sticky;
      top: 0;
      z-index: 100;
      min-height: 68px;
      background: rgba(255, 255, 255, 0.96);
      border-bottom: 1px solid var(--border);
      backdrop-filter: blur(10px);
    }

    .header-inner {
      width: min(1120px, calc(100% - 2rem));
      min-height: 68px;
      margin: 0 auto;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 1.5rem;
    }

    .logo {
      display: inline-flex;
      align-items: baseline;
      gap: 0.55rem;
      color: var(--accent);
      font-family: "Inter", sans-serif;
      font-weight: 800;
      letter-spacing: -0.03em;
    }

    .logo small {
      color: var(--ink-muted);
      font-family: "Noto Sans JP", sans-serif;
      font-size: 0.72rem;
      font-weight: 500;
      letter-spacing: 0;
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 1.6rem;
      margin: 0;
      padding: 0;
      list-style: none;
      color: var(--ink-soft);
      font-size: 0.88rem;
      font-weight: 700;
    }

    .nav-links a:hover,
    .nav-links a:focus-visible {
      color: var(--accent);
    }

    .hero {
      position: relative;
      overflow: hidden;
      background:
        radial-gradient(circle at 82% 14%, rgba(14, 165, 233, 0.24), transparent 30%),
        linear-gradient(135deg, var(--hero), var(--hero-soft));
      color: #ffffff;
    }

    .hero::after {
      content: "";
      position: absolute;
      right: -6rem;
      bottom: -8rem;
      width: 26rem;
      height: 26rem;
      border: 1px solid rgba(255, 255, 255, 0.09);
      border-radius: 50%;
      box-shadow:
        0 0 0 3rem rgba(255, 255, 255, 0.025),
        0 0 0 7rem rgba(255, 255, 255, 0.018);
    }

    .hero-inner {
      position: relative;
      z-index: 1;
      width: min(980px, calc(100% - 2rem));
      margin: 0 auto;
      padding: clamp(4.5rem, 9vw, 7rem) 0;
      text-align: center;
    }

    .eyebrow {
      display: inline-block;
      margin-bottom: 1.25rem;
      padding: 0.3rem 0.9rem;
      color: #7dd3fc;
      border: 1px solid rgba(125, 211, 252, 0.55);
      border-radius: 999px;
      background: rgba(14, 165, 233, 0.1);
      font-size: 0.78rem;
      font-weight: 700;
      letter-spacing: 0.08em;
    }

    .hero h1 {
      max-width: 860px;
      margin: 0 auto 1.3rem;
      font-size: clamp(2rem, 5vw, 3.75rem);
      font-weight: 900;
      letter-spacing: -0.045em;
      line-height: 1.25;
    }

    .hero h1 span {
      color: #38bdf8;
    }

    .hero-lead {
      max-width: 720px;
      margin: 0 auto 2.2rem;
      color: #cbd5e1;
      font-size: clamp(0.98rem, 2vw, 1.12rem);
    }

    .hero-stats {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      gap: 0.7rem;
      margin: 0;
      padding: 0;
      list-style: none;
    }

    .hero-stats li {
      padding: 0.55rem 0.9rem;
      color: #e2e8f0;
      background: rgba(255, 255, 255, 0.07);
      border: 1px solid rgba(255, 255, 255, 0.12);
      border-radius: 0.5rem;
      font-size: 0.8rem;
    }

    .hero-stats strong {
      color: #ffffff;
    }

    .container {
      width: min(1120px, calc(100% - 2rem));
      margin: 0 auto;
      padding: 4rem 0 5rem;
    }

    .concept-box {
      display: grid;
      grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
      gap: 3rem;
      align-items: center;
      margin-bottom: 4.5rem;
      padding: clamp(1.5rem, 4vw, 2.75rem);
      background: var(--surface);
      border: 1px solid var(--border);
      border-radius: 1.1rem;
      box-shadow: var(--shadow);
    }

    .concept-copy h2 {
      margin: 0 0 0.9rem;
      font-size: clamp(1.35rem, 3vw, 1.8rem);
      line-height: 1.45;
    }

    .concept-copy p {
      margin: 0;
      color: var(--ink-soft);
      font-size: 0.95rem;
    }

    .concept-points {
      display: grid;
      gap: 0.9rem;
    }

    .concept-point {
      display: grid;
      grid-template-columns: 2.25rem 1fr;
      gap: 0.8rem;
      align-items: start;
    }

    .point-number {
      display: grid;
      place-items: center;
      width: 2.25rem;
      height: 2.25rem;
      color: var(--accent);
      background: var(--accent-pale);
      border-radius: 50%;
      font-family: "Inter", sans-serif;
      font-size: 0.78rem;
      font-weight: 800;
    }

    .concept-point strong {
      display: block;
      margin-bottom: 0.1rem;
      font-size: 0.92rem;
    }

    .concept-point p {
      margin: 0;
      color: var(--ink-muted);
      font-size: 0.82rem;
    }

    .section-header {
      display: flex;
      align-items: end;
      justify-content: space-between;
      gap: 1rem;
      margin-bottom: 1.5rem;
    }

    .section-title {
      position: relative;
      margin: 0;
      padding-left: 0.9rem;
      font-size: clamp(1.35rem, 3vw, 1.75rem);
      line-height: 1.4;
    }

    .section-title::before {
      content: "";
      position: absolute;
      top: 12%;
      bottom: 12%;
      left: 0;
      width: 4px;
      background: var(--accent-bright);
      border-radius: 99px;
    }

    .section-subtitle {
      margin: 0.3rem 0 0;
      color: var(--ink-muted);
      font-size: 0.88rem;
    }

    .article-tools {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 1rem;
      margin-bottom: 1.5rem;
    }

    .search-container {
      position: relative;
      width: min(100%, 520px);
    }

    .search-container label {
      display: block;
      margin-bottom: 0.4rem;
      color: var(--ink-soft);
      font-size: 0.8rem;
      font-weight: 700;
    }

    .search-container input {
      width: 100%;
      padding: 0.82rem 1rem;
      color: var(--ink);
      background: var(--surface);
      border: 2px solid var(--border);
      border-radius: 0.65rem;
      outline: none;
    }

    .search-container input:focus {
      border-color: var(--accent-bright);
      box-shadow: 0 0 0 3px rgba(14, 165, 233, 0.14);
    }

    .result-count {
      align-self: end;
      margin: 0 0 0.75rem;
      color: var(--ink-muted);
      font-size: 0.82rem;
      white-space: nowrap;
    }

    .article-grid {
      display: grid;
      grid-template-columns: repeat(2, minmax(0, 1fr));
      gap: 1.4rem;
      margin-bottom: 4.5rem;
    }

    .article-card {
      display: flex;
      flex-direction: column;
      min-width: 0;
      padding: 1.45rem;
      background: var(--surface);
      border: 1px solid var(--border);
      border-radius: 0.9rem;
      box-shadow: 0 7px 24px rgba(15, 23, 42, 0.045);
      transition:
        transform 0.2s ease,
        box-shadow 0.2s ease,
        border-color 0.2s ease;
    }

    .article-card:hover {
      transform: translateY(-3px);
      border-color: #bae6fd;
      box-shadow: var(--shadow);
    }

    .article-card[hidden] {
      display: none;
    }

    .card-meta {
      display: flex;
      flex-wrap: wrap;
      gap: 0.45rem;
      align-items: center;
      margin-bottom: 0.85rem;
      color: var(--ink-muted);
      font-size: 0.73rem;
    }

    .category-tag {
      padding: 0.17rem 0.55rem;
      color: var(--accent);
      background: var(--accent-pale);
      border-radius: 0.3rem;
      font-weight: 700;
    }

    .stock-code::before {
      content: "証券コード ";
    }

    .article-card h3 {
      margin: 0 0 0.75rem;
      font-size: 1.1rem;
      line-height: 1.5;
    }

    .article-card p {
      margin: 0 0 1.2rem;
      color: var(--ink-soft);
      font-size: 0.88rem;
    }

    .business-flow {
      display: flex;
      flex-wrap: wrap;
      gap: 0.35rem;
      margin: auto 0 1.2rem;
      padding: 0;
      list-style: none;
    }

    .business-flow li {
      padding: 0.15rem 0.48rem;
      color: #475569;
      background: #f1f5f9;
      border-radius: 999px;
      font-size: 0.7rem;
    }

    .read-more {
      display: inline-flex;
      align-items: center;
      align-self: flex-start;
      gap: 0.45rem;
      color: var(--accent);
      font-size: 0.84rem;
      font-weight: 700;
    }

    .read-more::after {
      content: "→";
      transition: transform 0.2s ease;
    }

    .read-more:hover::after {
      transform: translateX(0.2rem);
    }

    .read-more:focus-visible,
    .nav-links a:focus-visible,
    .category-link:focus-visible {
      outline: 3px solid var(--focus);
      outline-offset: 3px;
      border-radius: 0.2rem;
    }

    .empty-message {
      grid-column: 1 / -1;
      padding: 3rem 1rem;
      color: var(--ink-muted);
      background: var(--surface);
      border: 1px dashed var(--border);
      border-radius: 0.9rem;
      text-align: center;
    }

    .empty-message[hidden] {
      display: none;
    }

    .category-list {
      display: grid;
      grid-template-columns: repeat(3, minmax(0, 1fr));
      gap: 1rem;
      margin-bottom: 4.5rem;
    }

    .category-link {
      display: block;
      padding: 1.35rem;
      background: var(--surface);
      border: 1px solid var(--border);
      border-radius: 0.8rem;
      transition:
        background 0.2s ease,
        border-color 0.2s ease;
    }

    .category-link:hover {
      background: var(--surface-soft);
      border-color: #7dd3fc;
    }

    .category-link strong {
      display: block;
      margin-bottom: 0.3rem;
      font-size: 0.94rem;
    }

    .category-link span {
      color: var(--ink-muted);
      font-size: 0.78rem;
    }

    .reading-guide {
      padding: clamp(1.5rem, 4vw, 2.6rem);
      background: linear-gradient(135deg, #eff6ff, #f8fafc);
      border: 1px solid #bfdbfe;
      border-radius: 1rem;
    }

    .reading-guide h2 {
      margin: 0 0 0.7rem;
      font-size: clamp(1.25rem, 3vw, 1.65rem);
    }

    .reading-guide > p {
      margin: 0 0 1.3rem;
      color: var(--ink-soft);
      font-size: 0.9rem;
    }

    .guide-grid {
      display: grid;
      grid-template-columns: repeat(3, minmax(0, 1fr));
      gap: 1rem;
    }

    .guide-item {
      padding: 1rem;
      background: rgba(255, 255, 255, 0.75);
      border-radius: 0.7rem;
    }

    .guide-item strong {
      display: block;
      margin-bottom: 0.3rem;
      color: var(--accent);
      font-size: 0.86rem;
    }

    .guide-item p {
      margin: 0;
      color: var(--ink-muted);
      font-size: 0.78rem;
    }

    .site-footer {
      padding: 3.5rem 0 2rem;
      color: #94a3b8;
      background: var(--hero);
    }

    .footer-inner {
      width: min(1120px, calc(100% - 2rem));
      margin: 0 auto;
    }

    .footer-top {
      display: grid;
      grid-template-columns: 1.5fr 1fr;
      gap: 3rem;
      margin-bottom: 2rem;
    }

    .footer-brand h2 {
      margin: 0 0 0.7rem;
      color: #ffffff;
      font-family: "Inter", sans-serif;
      font-size: 1.1rem;
    }

    .footer-brand p,
    .footer-policy p {
      margin: 0;
      font-size: 0.78rem;
    }

    .footer-policy strong {
      display: block;
      margin-bottom: 0.45rem;
      color: #e2e8f0;
      font-size: 0.8rem;
    }

    .disclaimer {
      padding: 1rem;
      background: rgba(255, 255, 255, 0.04);
      border: 1px solid #263d55;
      border-radius: 0.6rem;
      font-size: 0.73rem;
    }

    .copyright {
      margin: 1.5rem 0 0;
      padding-top: 1.3rem;
      border-top: 1px solid #263d55;
      color: #64748b;
      font-family: "Inter", sans-serif;
      font-size: 0.7rem;
      text-align: center;
    }

    @media (max-width: 820px) {
      .concept-box,
      .footer-top {
        grid-template-columns: 1fr;
        gap: 1.7rem;
      }

      .article-grid {
        grid-template-columns: 1fr;
      }

      .category-list,
      .guide-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
      }
    }

    @media (max-width: 620px) {
      .nav-links {
        display: none;
      }

      .logo small {
        display: none;
      }

      .hero-inner {
        text-align: left;
      }

      .hero h1,
      .hero-lead {
        margin-left: 0;
      }

      .hero-stats {
        justify-content: flex-start;
      }

      .article-tools {
        align-items: stretch;
        flex-direction: column;
      }

      .result-count {
        align-self: flex-start;
        margin: 0;
      }

      .category-list,
      .guide-grid {
        grid-template-columns: 1fr;
      }
    }