:root {
      --orange-primary: #E67635;
      --orange-light: #F5A66A;
      --orange-dark: #C45A1A;
      --navy: #1e3a5f;
      --navy-dark: #152a45;
      --white: #ffffff;
      --off-white: #FAF8F5;
      --text-dark: #1a1a1a;
      --text-body: #4a4a4a;
      --gray-light: #f0f2f4;
    }

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

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: "Noto Sans JP", sans-serif;
      background: var(--white);
      color: var(--text-dark);
      line-height: 1.8;
    }

    /* ========== Header ========== */
    header {
      position: fixed;
      top: 0;
      left: 0;
      right: 0;
      z-index: 1000;
      padding: 1rem 3rem;
      background: var(--white);
      display: flex;
      justify-content: space-between;
      align-items: center;
      box-shadow: 0 2px 30px rgba(0,0,0,0.08);
    }

    .logo {
      display: flex;
      align-items: center;
      text-decoration: none;
    }

    .logo img {
      height: 36px;
      width: auto;
    }

    .logo span {
      color: var(--orange-primary);
    }

    nav {
      display: flex;
      gap: 2.5rem;
      align-items: center;
    }

    nav a {
      font-size: 0.85rem;
      color: var(--text-body);
      text-decoration: none;
      letter-spacing: 0.1em;
      transition: color 0.3s ease;
    }

    nav a:hover {
      color: var(--orange-primary);
    }

    .nav-contact {
      background: var(--orange-primary);
      color: var(--white) !important;
      padding: 0.75rem 1.5rem;
      border-radius: 4px;
    }

    /* ========== Page Header ========== */
    .page-header {
      padding: 10rem 2rem 5rem;
      background: var(--navy-dark);
      text-align: center;
      position: relative;
      overflow: hidden;
    }

    .page-header::before {
      content: 'KNOWLEDGE';
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
      font-family: "Cormorant Garamond", serif;
      font-size: clamp(6rem, 15vw, 12rem);
      color: rgba(255,255,255,0.03);
      white-space: nowrap;
      pointer-events: none;
    }

    .page-header-content {
      position: relative;
      z-index: 1;
    }

    .page-label {
      font-size: 0.75rem;
      letter-spacing: 0.3em;
      color: var(--orange-light);
      margin-bottom: 1rem;
      display: block;
    }

    .page-title {
      font-family: "Noto Serif JP", serif;
      font-size: clamp(2rem, 4vw, 3rem);
      font-weight: 500;
      color: var(--white);
      margin-bottom: 1rem;
    }

    .page-subtitle {
      font-size: 1rem;
      color: rgba(255,255,255,0.7);
    }

    /* ========== Filter ========== */
    .filter-section {
      padding: 3rem 2rem;
      background: var(--navy-dark);
    }

    .filter-container {
      max-width: 1200px;
      margin: 0 auto;
    }

    .knowledge-filter {
      display: flex;
      flex-wrap: wrap;
      gap: 12px;
      justify-content: center;
    }

    .filter-btn {
      padding: 10px 20px;
      background: transparent;
      border: 1px solid rgba(255, 255, 255, 0.3);
      color: rgba(255, 255, 255, 0.7);
      font-size: 0.875rem;
      border-radius: 30px;
      cursor: pointer;
      transition: all 0.3s ease;
      font-family: inherit;
    }

    .filter-btn:hover {
      border-color: #D4A03C;
      color: #D4A03C;
    }

    .filter-btn.active {
      background: #D4A03C;
      border-color: #D4A03C;
      color: #fff;
    }

    /* ========== Articles Grid ========== */
    .articles-section {
      padding: 5rem 2rem;
      background: var(--off-white);
    }

    .articles-container {
      max-width: 1200px;
      margin: 0 auto;
    }

    .articles-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 2rem;
    }

    .loading-text {
      text-align: center;
      color: var(--text-body);
      padding: 3rem;
      grid-column: 1 / -1;
    }

    .no-data {
      text-align: center;
      color: var(--text-body);
      padding: 3rem;
      grid-column: 1 / -1;
      background: var(--off-white);
      border: 2px dashed rgba(0,0,0,0.1);
    }

    .article-card-placeholder {
      width: 100%;
      height: 100%;
      background: var(--off-white);
    }

    .article-card {
      background: var(--white);
      text-decoration: none;
      color: inherit;
      overflow: hidden;
      transition: transform 0.4s ease, box-shadow 0.4s ease;
    }

    .article-card:hover {
      transform: translateY(-10px);
      box-shadow: 0 20px 50px rgba(0,0,0,0.1);
    }

    .article-card-image {
      position: relative;
      aspect-ratio: 16/10;
      overflow: hidden;
    }

    .article-card-image img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: transform 0.6s ease;
    }

    .article-card:hover .article-card-image img {
      transform: scale(1.1);
    }

    .article-card-category {
      position: absolute;
      top: 1rem;
      left: 1rem;
      background: var(--orange-primary);
      color: var(--white);
      font-size: 0.7rem;
      font-weight: 600;
      letter-spacing: 0.1em;
      padding: 0.35rem 0.75rem;
    }

    .article-card-category.column {
      background: var(--orange-primary);
    }

    .article-card-category.report {
      background: var(--navy);
    }

    .article-card-category.news {
      background: #2d8659;
    }

    .article-card-content {
      padding: 1.5rem;
    }

    .article-card-date {
      font-family: "Cormorant Garamond", serif;
      font-size: 0.85rem;
      color: var(--text-body);
      display: block;
      margin-bottom: 0.75rem;
    }

    .article-card-title {
      font-size: 1.1rem;
      font-weight: 600;
      line-height: 1.6;
      margin-bottom: 0.75rem;
      display: -webkit-box;
      -webkit-line-clamp: 2;
      -webkit-box-orient: vertical;
      overflow: hidden;
    }

    .article-card-excerpt {
      font-size: 0.85rem;
      color: var(--text-body);
      line-height: 1.8;
      display: -webkit-box;
      -webkit-line-clamp: 2;
      -webkit-box-orient: vertical;
      overflow: hidden;
    }

    /* ========== Pagination ========== */
    .pagination {
      display: flex;
      justify-content: center;
      gap: 0.5rem;
      margin-top: 4rem;
    }

    .pagination a,
    .pagination span {
      width: 45px;
      height: 45px;
      display: flex;
      align-items: center;
      justify-content: center;
      background: var(--white);
      border: 1px solid rgba(0,0,0,0.1);
      color: var(--text-body);
      text-decoration: none;
      font-size: 0.9rem;
      transition: all 0.3s ease;
    }

    .pagination a:hover,
    .pagination span.current {
      background: var(--orange-primary);
      border-color: var(--orange-primary);
      color: var(--white);
    }

    /* ========== Footer ========== */
    footer {
      background: var(--navy-dark);
      padding: 5rem 2rem 2rem;
      color: var(--white);
    }

    .footer-container {
      max-width: 1200px;
      margin: 0 auto;
    }

    .footer-top {
      display: flex;
      justify-content: space-between;
      align-items: flex-start;
      margin-bottom: 4rem;
      flex-wrap: wrap;
      gap: 3rem;
    }

    .footer-logo {
      margin-bottom: 1rem;
    }

    .footer-logo img {
      height: 36px;
      width: auto;
    }

    .footer-logo span {
      color: var(--orange-primary);
    }

    .footer-tagline {
      font-size: 0.85rem;
      color: rgba(255,255,255,0.5);
    }

    .footer-links {
      display: flex;
      gap: 4rem;
    }

    .footer-links-group h4 {
      font-size: 0.75rem;
      letter-spacing: 0.15em;
      color: var(--orange-light);
      margin-bottom: 1rem;
    }

    .footer-links-group ul {
      list-style: none;
    }

    .footer-links-group li {
      margin-bottom: 0.75rem;
    }

    .footer-links-group a {
      font-size: 0.85rem;
      color: rgba(255,255,255,0.6);
      text-decoration: none;
      transition: color 0.3s ease;
    }

    .footer-links-group a:hover {
      color: var(--orange-light);
    }

    .footer-bottom {
      border-top: 1px solid rgba(255,255,255,0.1);
      padding-top: 2rem;
      text-align: center;
    }

    .footer-copy {
      font-size: 0.75rem;
      color: rgba(255,255,255,0.4);
    }

    /* ========== Responsive ========== */
    @media (max-width: 900px) {
      header {
        padding: 1rem 1.5rem;
      }

      nav {
        display: none;
      }

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

      .footer-top {
        flex-direction: column;
      }

      .footer-links {
        flex-direction: column;
        gap: 2rem;
      }
    }

    @media (max-width: 768px) {
      .knowledge-filter {
        gap: 8px;
      }

      .filter-btn {
        padding: 8px 16px;
        font-size: 0.8rem;
      }
    }