@charset "UTF-8";
/* CSS Document */
  :root {
    --bg: #f7f5f0;
    --paper: #fefcf8;
    --ink: #1a1714;
    --muted: #6b6560;
    --accent: #2d5a8e;
    --accent-light: #e8eff8;
    --rule: #d4cfc8;
    --bar: #2d5a8e;
    --line: #c0392b;
    --year-badge: #1a1714;
  }

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

  body {
    background: var(--bg);
    color: var(--ink);
    font-family:
      'Noto Sans JP',
      'Yu Gothic',
      'Yu Gothic Medium',
      'Hiragino Kaku Gothic ProN',
      'Helvetica Neue',
      Arial,
      sans-serif;
    font-size: 16px;
    line-height: 1.7;
  }

  /* ── Header ── */


  /* ── Main layout ── */
  .container {
    max-width: 960px;
    margin: 0 auto;
    padding: 3rem 1.5rem 6rem;
  }

  /* ── Stats bar ── */
  .stats-bar {
    display: flex;
    gap: 2rem;
    margin-bottom: 2.5rem;
    padding: 1.25rem 1.5rem;
    background: var(--paper);
    border: 1px solid var(--rule);
    border-radius: 2px;
  }
  .stat-item { text-align: center; }
  .stat-num {
    font-size: 2rem;
    font-weight: 600;
    color: var(--accent);
    line-height: 1;
  }
  .stat-label {
    font-family: 'Noto Sans JP', 'Yu Gothic', 'Helvetica Neue', Arial, sans-serif;
    font-size: 0.65rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--muted);
    margin-top: 0.25rem;
  }

  /* ── Chart Section ── */
  .chart-section {
    background: var(--paper);
    border: 1px solid var(--rule);
    border-radius: 2px;
    padding: 2rem 2rem 1.5rem;
    margin-bottom: 3rem;
  }
  .chart-title {
    font-family: 'Noto Sans JP', 'Yu Gothic', 'Helvetica Neue', Arial, sans-serif;
    font-size: 0.7rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--muted);
    margin-bottom: 1.5rem;
  }
  .chart-wrap {
    position: relative;
    height: 220px;
  }
  canvas#pubChart { width: 100% !important; height: 100% !important; }

  .chart-legend {
    display: flex;
    gap: 1.5rem;
    margin-top: 1rem;
    font-family: 'Noto Sans JP', 'Yu Gothic', 'Helvetica Neue', Arial, sans-serif;
    font-size: 0.65rem;
    color: var(--muted);
    letter-spacing: 0.08em;
  }
  .legend-item { display: flex; align-items: center; gap: 0.4rem; }
  .legend-dot {
    width: 10px; height: 10px; border-radius: 1px; flex-shrink: 0;
  }

  /* ── Year section ── */
  .year-block {
    margin-bottom: 2.5rem;
  }

  .year-header {
    display: flex;
    align-items: baseline;
    gap: 1rem;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--ink);
  }
  .year-num {
    font-size: 1.6rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    color: var(--ink);
  }
  .year-count {
    font-family: 'Noto Sans JP', 'Yu Gothic', 'Helvetica Neue', Arial, sans-serif;
    font-size: 0.7rem;
    color: var(--muted);
    letter-spacing: 0.1em;
  }

  /* ── Paper entry ── */
  .paper-list {
    list-style: none;
  }
  .paper-item {
    display: grid;
    grid-template-columns: 1fr;
    gap: 0 0.75rem;
    padding: 0.9rem 0;
    border-bottom: 1px solid var(--rule);
    transition: background 0.15s;
  }
  .paper-item:hover {
    background: var(--accent-light);
    margin: 0 -0.75rem;
    padding-left: 0.75rem;
    padding-right: 0.75rem;
    border-radius: 2px;
  }
  .paper-num { display: none; }
  .paper-body {}
  .paper-authors {
    font-size: 1.10rem;
    font-weight: 400;
    color: var(--ink);
    margin-bottom: 0.15rem;
  }
  .paper-title {
    font-size: 1.30rem;
    font-weight: 500;
    color: var(--ink);
    margin-bottom: 0.2rem;
    line-height: 1.55;
  }
  .paper-title a {
    color: inherit;
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: border-color 0.15s, color 0.15s;
  }
  .paper-title a:hover {
    color: var(--accent);
    border-bottom-color: var(--accent);
  }
  .paper-ref {
    font-size: 1.08rem;
    color: var(--muted);
  }
  .paper-ref .journal {
    font-style: italic;
    color: var(--ink);
  }
  .paper-ref .volume {
    font-style: italic;
  }

  .paper-ref strong {
    font-weight: 700;
    color: var(--ink);
  }

  .paper-ref a {
    color: inherit;
    text-decoration: none;
  }

  .paper-ref a:hover {
    color: var(--accent);
    text-decoration: underline;
  }
  .paper-ref .doi-link {
    font-family: 'Noto Sans JP', 'Yu Gothic', 'Helvetica Neue', Arial, sans-serif;
    font-size: 0.72rem;
    color: var(--accent);
    text-decoration: none;
    margin-left: 0.4rem;
    opacity: 0.8;
  }
  .paper-ref .doi-link:hover { opacity: 1; text-decoration: underline; }

  /* ── Footer ── */
  footer {
    text-align: center;
    padding: 2rem;
    font-family: 'Noto Sans JP', 'Yu Gothic', 'Helvetica Neue', Arial, sans-serif;
    font-size: 0.65rem;
    color: var(--muted);
    letter-spacing: 0.1em;
    border-top: 1px solid var(--rule);
  }

  @media (max-width: 600px) {
    header h1 { font-size: 1.7rem; }
    .stats-bar { flex-wrap: wrap; }
    .chart-wrap { height: 160px; }
  }

  html {
    scroll-behavior: smooth;
  }

  .year-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem 0.7rem;
    align-items: center;
    margin: -2rem 0 3rem;
    padding: 1rem 1.25rem;
    background: var(--paper);
    border: 1px solid var(--rule);
    border-radius: 2px;
    font-size: 0.95rem;
  }

  .year-nav a {
    color: var(--accent);
    text-decoration: none;
    font-weight: 500;
  }

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

  .year-nav .separator {
    color: var(--muted);
  }

  .year-block {
    scroll-margin-top: 1.5rem;
  }


  .back-to-top {
    position: fixed;
    right: 2.5rem;
    bottom: 2.5rem;
    z-index: 1000;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 4.5rem;
    height: 4.5rem;
    border-radius: 50%;
    background: var(--accent);
    color: #fff;
    font-size: 1.15rem;
    font-weight: 700;
    letter-spacing: 0.04em;
    text-decoration: none;
    box-shadow: 0 4px 14px rgba(0, 0, 0, 0.18);
    opacity: 0.9;
    transition: opacity 0.15s, transform 0.15s;
  }

  .back-to-top:hover {
    opacity: 1;
    transform: translateY(-2px);
    text-decoration: none;
  }

  @media (max-width: 600px) {
    .back-to-top {
      right: 1.5rem;
      bottom: 1.5rem;
      width: 3.8rem;
      height: 3.8rem;
      font-size: 1.0rem;
    }
  }