@font-face {
      font-family: RobotoConBold;
      src: url(../data/font/RobotoCondensed-Bold.ttf);
      font-weight: 700;
      font-style: normal;
    }
* {
  box-sizing: border-box;
}
    :root {
      --bg: #f6f4ee;
      --paper: #fffdf7;
      --ink: #1f2430;
      --ink-soft: #4d5667;
      --accent: #0c7a5b;
      --accent-soft: #c7efdf;
      --warn: #cb4d3f;
      --warn-soft: #ffd7d0;
      --line: #dbd3c5;
      --shadow: 0 14px 38px rgba(31, 36, 48, 0.12);
    }

    body {
      margin: 0;
      color: var(--ink);
      font-family: RobotoConBold;
      background:
        radial-gradient(1200px 650px at 5% -10%, #fce4b2 0%, transparent 45%),
        radial-gradient(1200px 650px at 95% 0%, #e4f6ef 0%, transparent 42%),
        linear-gradient(180deg, #f8f6ef 0%, #f0ece1 100%);
      min-height: 100vh;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 28px 18px 44px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100vh;
    }

    h1 {
      margin: 0;
      font-size: clamp(1.45rem, 3.4vw, 2.2rem);
      letter-spacing: 0.01em;
      text-align: center;
    }

    /* Book Cards */
    .books-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
      gap: 32px;
      margin-top: 32px;
      width: 100%;
      max-width: 700px;
      justify-items: center;
    }

    .book-card {
      display: flex;
      flex-direction: column;
      align-items: center;
      text-align: center;
      cursor: pointer;
      transition: transform 240ms ease, filter 240ms ease;
    }

    .book-card:hover {
      transform: translateY(-8px);
      filter: drop-shadow(0 16px 32px rgba(31, 36, 48, 0.2));
    }

    .book-card img {
      width: 100%;
      height: auto;
      border-radius: 12px;
      box-shadow: 0 12px 28px rgba(31, 36, 48, 0.15);
      margin-bottom: 20px;
      object-fit: cover;
      aspect-ratio: 2/3;
    }

    .book-info h2 {
      margin: 0 0 6px;
      font-size: 1.4rem;
      font-weight: 700;
      color: var(--ink);
      letter-spacing: 0.01em;
    }

    .book-info .author {
      margin: 0;
      font-size: 0.95rem;
      color: var(--ink-soft);
      font-weight: 500;
    }

    .viewer-overlay {
      position: fixed;
      inset: 0;
      display: flex;
      align-items: center;
      justify-content: center;
      background: rgba(143, 139, 79, 0.5);
      backdrop-filter: blur(8px);
      z-index: 1000;
      padding: 20px;
    }

    .viewer-overlay.hidden {
      display: none;
    }

    .viewer-shell {
      width: min(96vw, 900px);
      max-height: 95vh;
      background: var(--paper);
      border: 2px solid var(--line);
      border-radius: 22px;
      box-shadow: 0 32px 80px rgba(15, 20, 30, 0.28);
      overflow: visible;
      display: flex;
      flex-direction: column;
    }

    .viewer-header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 12px;
      padding: 14px 16px 10px;
      flex-wrap: wrap;
      align-items: center;
      justify-content: center;
    }

    .viewer-title {
      font-size: 1.1rem;
      font-weight: 700;
      color: var(--ink);
      margin: 0;
    }

    .viewer-close {
      padding: 8px 10px;
      font-size: 0.92rem;
    }

    .viewer-subtitle {
      font-size: 0.95rem;
      color: var(--ink-soft);
    }

    .viewer-close,
    .viewer-btn {
      border: none;
      border-radius: 12px;
      padding: 10px 14px;
      background: #fff;
      color: var(--ink);
      border: 1px solid var(--line);
      cursor: pointer;
      font-size: 0.95rem;
      transition: transform 120ms ease, background 120ms ease, border-color 120ms ease;
    }

    .viewer-close:hover,
    .viewer-btn:hover {
      background: var(--accent-soft);
      border-color: var(--accent);
      color: var(--ink);
      transform: translateY(-1px);
    }

    .viewer-actions {
      display: flex;
      flex-wrap: wrap;
      align-items: center;
      gap: 12px;
      padding: 0 24px 20px;
    }

    .viewer-control-row {
      display: flex;
      gap: 10px;
      width: 100%;
      flex-wrap: wrap;
      align-items: center;
      justify-content: center;
    }

    .viewer-control-row .viewer-btn,
    .viewer-control-row .viewer-close {
      flex: 1 1 1;
      min-width: 0;
      
    }

    .viewer-page-controls {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 12px;
      padding: 0 24px 20px;
      border-top: 1px solid #e6ddd1;
      border-radius: 0 0 22px 22px;
      background: #f8f5ef;
    }

    .viewer-page-label {
      font-size: 0.95rem;
      font-weight: 700;
      color: var(--ink);
    }

    .viewer-settings {
      position: relative;
    }

    .viewer-settings-toggle {
      min-width: 42px;
      width: 42px;
      height: 42px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 0;
      border-radius: 12px;
      font-size: 1.1rem;
    }

    .viewer-settings-panel {
      position: absolute;
      top: calc(100% + 8px);
      left: 0;
      right: auto;
      display: flex;
      flex-direction: column;
      gap: 10px;
      min-width: 150px;
      max-width: calc(100vw - 40px);
      width: min(220px, calc(100vw - 40px));
      padding: 12px;
      background: #fff;
      border: 1px solid var(--line);
      border-radius: 16px;
      box-shadow: 0 12px 40px rgba(0, 0, 0, 0.08);
      z-index: 10;
    }

    .viewer-settings-panel.hidden {
      display: none;
    }

    .viewer-settings-label {
      font-size: 0.82rem;
      font-weight: 700;
      color: var(--ink-soft);
      text-transform: uppercase;
      letter-spacing: 0.04em;
    }

    .viewer-res-switch {
      display: inline-flex;
      justify-content: center;
      gap: 4px;
      background: #f1efe9;
      border: 1px solid var(--line);
      border-radius: 999px;
      overflow: hidden;
      width: auto;
    }

    .viewer-res-btn {
      border: none;
      background: transparent;
      color: var(--ink);
      padding: 10px 16px;
      cursor: pointer;
      font-size: 0.95rem;
    }

    .viewer-res-btn.active {
      background: var(--accent);
      color: #fff;
    }

    .viewer-zoom-controls {
      display: flex;
      align-items: center;
      gap: 10px;
      font-size: 0.95rem;
      color: var(--ink);

      width: 100%;
      flex-wrap: wrap;
      align-items: center;
      justify-content: center;
    }

    .viewer-zoom-controls span {
      min-width: 56px;
      text-align: center;
      font-weight: 700;
    }

    .viewer-reset {
      background: var(--accent);
      color: #fff;
    }

    .viewer-image-frame {
      position: relative;
      background: #e9e3d9;
      border-top: 1px solid var(--line);
      flex: 1;
      overflow: hidden;
      min-height: 75vh;
      max-height: calc(100vh - 180px);
      cursor: grab;
    }

    .viewer-image-frame:active {
      cursor: grabbing;
    }

    #viewerImage {
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%) scale(1);
      transform-origin: center center;
      max-width: 100%;
      max-height: 100%;
      width: auto;
      height: auto;
      object-fit: contain;
      user-select: none;
      touch-action: none;
    }

    @media (max-width: 860px) {
      .viewer-header,
      .viewer-actions,
      .viewer-page-controls {
        flex-direction: column;
        align-items: stretch;
      }

      .viewer-header {
        align-items: center;
        gap: 8px;
        padding: 10px 12px 8px;
      }

      .viewer-title {
        font-size: 0.98rem;
      }

      .viewer-subtitle {
        font-size: 0.88rem;
      }

      .viewer-actions,
      .viewer-page-controls {
        gap: 8px;
        padding-left: 14px;
        padding-right: 14px;
      }

      .viewer-page-controls {
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
        padding-top: 10px;
        padding-bottom: 12px;
      }

      .viewer-res-switch,
      .viewer-zoom-controls {
        width: 100%;
      }

      .viewer-close {
        
      }

      .viewer-res-switch {
        justify-content: center;
        width: auto;
      }

      .viewer-zoom-controls {
        justify-content: space-between;
      }

      .viewer-btn,
      .viewer-res-btn {
        min-height: 38px;
        padding: 8px 12px;
        font-size: 0.92rem;
      }

      .viewer-page-controls .viewer-btn {
        width: auto;
        flex: 1 1 0;
      }

      .viewer-page-label {
        width: auto;
        text-align: center;
        font-size: 0.92rem;
        flex: 1 1 0;
      }
    }

    @media (max-width: 560px) {
      .viewer-shell {
        width: min(98vw, 100%);
      }

      .viewer-header,
      .viewer-actions,
      .viewer-page-controls {
        padding-left: 10px;
        padding-right: 10px;
      }

      .viewer-title {
        font-size: 0.98rem;
      }

      .viewer-subtitle {
        font-size: 0.85rem;
      }

      .viewer-page-controls {
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
        gap: 6px;
      }

      .viewer-page-controls .viewer-btn {
        width: auto;
        flex: 1 1 0;
      }

      .viewer-page-label {
        width: auto;
        font-size: 0.88rem;
        text-align: center;
        flex: 1 1 0;
      }

      .viewer-btn,
      .viewer-res-btn {
        padding: 8px 10px;
        font-size: 0.88rem;
      }

      .viewer-settings-panel {
        left: 0;
        transform: none;
        width: min(220px, calc(100vw - 24px));
        position: absolute;
        top: calc(100% + 8px);
        bottom: auto;
        max-height: calc(100vh - 120px);
        overflow-y: auto;
        z-index: 1100;
      }
    .viewer-image-frame {
      min-height: 75vh;
      max-height: calc(100vh - 180px);
    }
    }