:root {
    --paper: #EFEAE1;
    --paper-soft: #E2D9C9;
    --paper-raised: #F7F3EC;
    --ink: #241F1C;
    --ink-soft: #6B6058;
    --ink-faint: #94897C;
    --accent: #8C2F39;
    --accent-soft: #B5555F;
    --accent2: #3F6B63;
    --accent2-soft: #578179;
    --line: rgba(36, 31, 28, 0.14);
    --shadow: rgba(36, 31, 28, 0.16);
  }

  @media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
      --paper: #1B1815;
      --paper-soft: #262019;
      --paper-raised: #221D19;
      --ink: #EDE6DA;
      --ink-soft: #A79C8E;
      --ink-faint: #766B5F;
      --accent: #E08A90;
      --accent-soft: #C1636B;
      --accent2: #7FBEB1;
      --accent2-soft: #97CBC0;
      --line: rgba(237, 230, 218, 0.16);
      --shadow: rgba(0, 0, 0, 0.4);
    }
  }

  :root[data-theme="dark"] {
    --paper: #1B1815;
    --paper-soft: #262019;
    --paper-raised: #221D19;
    --ink: #EDE6DA;
    --ink-soft: #A79C8E;
    --ink-faint: #766B5F;
    --accent: #E08A90;
    --accent-soft: #C1636B;
    --accent2: #7FBEB1;
    --accent2-soft: #97CBC0;
    --line: rgba(237, 230, 218, 0.16);
    --shadow: rgba(0, 0, 0, 0.4);
  }

  * { box-sizing: border-box; }

  body {
    margin: 0;
    background: var(--paper);
    color: var(--ink);
    font-family: "Gowun Dodum", "Malgun Gothic", sans-serif;
    line-height: 1.6;
  }

  .wrap {
    max-width: 920px;
    margin: 0 auto;
    padding: 2.5rem 1.5rem 5rem;
  }

  /* header */

  .site-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 1.5rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--line);
    margin-bottom: 2.25rem;
  }

  @media (max-width: 640px) {
    .site-header {
      flex-direction: column;
      align-items: stretch;
      gap: 1.1rem;
    }

    .header-actions {
      flex-wrap: wrap;
    }
  }

  .brand {
    display: flex;
    align-items: flex-start;
    gap: 0.9rem;
  }

  .ribbon {
    width: 10px;
    height: 52px;
    flex: none;
    background: var(--accent);
    clip-path: polygon(0 0, 100% 0, 100% 78%, 50% 100%, 0 78%);
    margin-top: 2px;
  }

  .brand h1 {
    margin: 0;
    font-family: "Gowun Batang", "Malgun Gothic", serif;
    font-weight: 700;
    font-size: clamp(1.9rem, 4vw, 2.4rem);
    letter-spacing: 0.02em;
  }

  .tagline {
    margin: 0.3rem 0 0;
    color: var(--ink-soft);
    font-size: 0.92rem;
  }

  .btn-primary {
    flex: none;
    background: var(--accent);
    color: var(--paper-raised);
    border: none;
    border-radius: 3px;
    padding: 0.65rem 1.1rem;
    font-family: inherit;
    font-size: 0.95rem;
    cursor: pointer;
    transition: background 0.15s ease, transform 0.15s ease;
  }

  .btn-primary:hover { background: var(--accent-soft); }
  .btn-primary:active { transform: translateY(1px); }
  .btn-primary:disabled { opacity: 0.5; cursor: not-allowed; }

  .btn-random {
    flex: none;
    background: var(--accent2);
    color: var(--paper-raised);
    border: none;
    border-radius: 3px;
    padding: 0.65rem 1.1rem;
    font-family: inherit;
    font-size: 0.95rem;
    cursor: pointer;
    transition: background 0.15s ease, transform 0.15s ease;
  }

  .btn-random:hover { background: var(--accent2-soft); }
  .btn-random:active { transform: translateY(1px); }

  .btn-primary:focus-visible,
  button:focus-visible,
  input:focus-visible,
  textarea:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
  }

  /* auth */

  .header-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex: none;
  }

  .auth-box { display: flex; align-items: center; }

  .user-chip {
    display: flex;
    align-items: center;
    gap: 0.5rem;
  }

  .user-avatar {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    object-fit: cover;
    flex: none;
    background: var(--paper-soft);
  }

  .user-name {
    font-size: 0.88rem;
    color: var(--ink-soft);
    max-width: 100px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .btn-logout {
    background: none;
    border: none;
    color: var(--ink-faint);
    font-family: inherit;
    font-size: 0.8rem;
    cursor: pointer;
    text-decoration: underline;
    padding: 0;
  }

  .btn-logout:hover { color: var(--accent); }

  .signin-prompt {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 0.6rem;
    background: var(--paper-soft);
    border: 1px dashed var(--line);
    border-radius: 4px;
    padding: 0.8rem 1rem;
    font-size: 0.88rem;
    color: var(--ink-soft);
  }

  /* library grid */

  .library-toolbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    flex-wrap: wrap;
    margin-bottom: 1.1rem;
  }

  .library-meta {
    color: var(--ink-faint);
    font-size: 0.85rem;
    letter-spacing: 0.04em;
    margin: 0;
    font-variant-numeric: tabular-nums;
  }

  .sort-tabs {
    display: flex;
    gap: 0.4rem;
  }

  .sort-tab {
    background: none;
    border: 1px solid var(--line);
    color: var(--ink-soft);
    border-radius: 999px;
    padding: 0.4rem 0.85rem;
    font-family: inherit;
    font-size: 0.82rem;
    cursor: pointer;
  }

  .sort-tab:hover { border-color: var(--ink-soft); color: var(--ink); }

  .sort-tab.active {
    background: var(--accent);
    border-color: var(--accent);
    color: var(--paper-raised);
  }

  .search-box input[type="search"] {
    width: 220px;
    max-width: 100%;
    font-family: inherit;
    font-size: 0.9rem;
    color: var(--ink);
    background: var(--paper-raised);
    border: 1px solid var(--line);
    border-radius: 999px;
    padding: 0.45rem 0.9rem;
  }

  .shelf {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    gap: 1.1rem;
  }

  .book-card {
    position: relative;
    display: block;
    aspect-ratio: 2 / 3;
    text-align: left;
    background: var(--cover, var(--accent));
    color: #F3EEE4;
    border: none;
    border-radius: 4px;
    padding: 0;
    overflow: hidden;
    cursor: pointer;
    font-family: inherit;
    box-shadow: 0 3px 10px var(--shadow);
    transition: transform 0.15s ease, box-shadow 0.15s ease;
  }

  .book-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 18px var(--shadow);
  }

  .b-cover-img {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    z-index: 1;
  }

  .b-new-badge {
    position: absolute;
    top: 0.55rem;
    right: 0.55rem;
    z-index: 3;
    background: #E0483C;
    color: #fff;
    font-size: 0.68rem;
    font-weight: 700;
    letter-spacing: 0.03em;
    padding: 0.18rem 0.45rem;
    border-radius: 999px;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.35);
  }

  .b-overlay {
    position: absolute;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 2;
    padding: 0.85rem 0.8rem 0.75rem;
    background: linear-gradient(to top, rgba(10, 8, 6, 0.85) 0%, rgba(10, 8, 6, 0.55) 48%, rgba(10, 8, 6, 0) 100%);
  }

  .book-card .b-title {
    font-family: "Gowun Batang", serif;
    font-weight: 700;
    font-size: 1.05rem;
    line-height: 1.35;
    text-wrap: balance;
    margin: 0 0 0.3rem;
  }

  .book-card .b-author {
    font-size: 0.8rem;
    opacity: 0.9;
    margin: 0 0 0.5rem;
  }

  .book-card .b-stars {
    font-size: 0.8rem;
    letter-spacing: 0.02em;
    font-variant-numeric: tabular-nums;
  }

  .empty-note {
    color: var(--ink-faint);
    font-size: 0.9rem;
    padding: 1.5rem 0;
  }

  /* form */

  .panel {
    background: var(--paper-raised);
    border: 1px solid var(--line);
    border-radius: 6px;
    padding: 1.75rem;
  }

  .panel h2 {
    font-family: "Gowun Batang", serif;
    margin: 0 0 1.4rem;
    font-size: 1.4rem;
  }

  .field {
    margin-bottom: 1.15rem;
  }

  .field label {
    display: block;
    font-size: 0.82rem;
    color: var(--ink-soft);
    letter-spacing: 0.03em;
    margin-bottom: 0.4rem;
  }

  .field input[type="text"],
  .field input[type="email"],
  .field textarea {
    width: 100%;
    font-family: inherit;
    font-size: 1rem;
    color: var(--ink);
    background: var(--paper);
    border: 1px solid var(--line);
    border-radius: 3px;
    padding: 0.6rem 0.7rem;
    resize: vertical;
  }

  .field textarea { min-height: 110px; line-height: 1.6; }

  .book-search-row {
    display: flex;
    gap: 0.6rem;
  }

  .book-search-row input {
    flex: 1;
    font-family: inherit;
    font-size: 1rem;
    color: var(--ink);
    background: var(--paper);
    border: 1px solid var(--line);
    border-radius: 3px;
    padding: 0.6rem 0.7rem;
  }

  .book-results {
    list-style: none;
    margin: 0.8rem 0 0;
    padding: 0;
    max-height: 380px;
    overflow-y: auto;
    border: 1px solid var(--line);
    border-radius: 4px;
  }

  .book-results li + li { border-top: 1px solid var(--line); }

  .book-result-empty {
    padding: 0.9rem;
    color: var(--ink-faint);
    font-size: 0.88rem;
  }

  .book-result-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    width: 100%;
    background: none;
    border: none;
    padding: 0.85rem 0.9rem;
    font-family: inherit;
    text-align: left;
    cursor: pointer;
    color: var(--ink);
  }

  .book-result-item:hover { background: var(--paper-soft); }

  .book-result-item img,
  .book-result-noimg {
    width: 68px;
    aspect-ratio: 2 / 3;
    flex: none;
    border-radius: 4px;
    object-fit: cover;
    background: var(--paper-soft);
    box-shadow: 0 2px 6px var(--shadow);
  }

  .book-result-noimg {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.68rem;
    color: var(--ink-faint);
    text-align: center;
    line-height: 1.3;
  }

  .book-result-title {
    font-size: 1.02rem;
    line-height: 1.4;
  }

  .book-result-author {
    font-size: 0.85rem;
    color: var(--ink-faint);
    margin-top: 0.2rem;
  }

  .selected-book {
    display: flex;
    align-items: center;
    gap: 1rem;
    background: var(--paper-soft);
    border: 1px solid var(--line);
    border-radius: 4px;
    padding: 0.9rem 1rem;
  }

  .selected-book-cover {
    width: 76px;
    aspect-ratio: 2 / 3;
    flex: none;
    border-radius: 4px;
    overflow: hidden;
    background: var(--cover, var(--accent));
    box-shadow: 0 2px 8px var(--shadow);
  }

  .selected-book-cover img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
  }

  .selected-book-info { flex: 1; min-width: 0; }

  .selected-book-title {
    font-family: "Gowun Batang", serif;
    font-size: 1.05rem;
  }

  .selected-book-author {
    font-size: 0.85rem;
    color: var(--ink-faint);
    margin-top: 0.2rem;
  }

  .star-picker {
    display: flex;
    gap: 0.25rem;
  }

  .star-picker button {
    background: none;
    border: none;
    font-size: 1.6rem;
    line-height: 1;
    cursor: pointer;
    color: var(--ink-faint);
    padding: 0.1rem;
  }

  .star-picker button.filled { color: var(--accent); }
  .star-picker button:hover { color: var(--accent-soft); }

  .form-actions {
    display: flex;
    justify-content: flex-end;
    gap: 0.6rem;
    margin-top: 1.5rem;
  }

  .btn-ghost {
    background: none;
    border: 1px solid var(--line);
    color: var(--ink-soft);
    border-radius: 3px;
    padding: 0.6rem 1rem;
    font-family: inherit;
    cursor: pointer;
  }

  .btn-ghost:hover { border-color: var(--ink-soft); color: var(--ink); }

  .btn-accent-outline {
    background: none;
    border: 1px solid var(--accent);
    color: var(--accent);
    border-radius: 3px;
    padding: 0.6rem 1rem;
    font-family: inherit;
    font-weight: 600;
    cursor: pointer;
  }

  .btn-accent-outline:hover { background: var(--accent); color: var(--paper-raised); }

  /* detail */

  .back-btn {
    background: none;
    border: none;
    color: var(--ink-soft);
    font-family: inherit;
    font-size: 0.9rem;
    cursor: pointer;
    padding: 0.3rem 0;
    margin-bottom: 1.25rem;
  }

  .back-btn:hover { color: var(--accent); }

  .detail-top {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 1.5rem;
    margin-bottom: 1.4rem;
    padding-bottom: 1.4rem;
    border-bottom: 1px solid var(--line);
  }

  .detail-cover {
    width: clamp(160px, 26vw, 240px);
    aspect-ratio: 2 / 3;
    flex: none;
    border-radius: 6px;
    overflow: hidden;
    background: var(--cover, var(--accent));
    box-shadow: 0 4px 14px var(--shadow);
  }

  .detail-cover img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
  }

  .detail-card header {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
    flex: 1;
    min-width: 200px;
  }

  .detail-card h2 {
    font-family: "Gowun Batang", serif;
    font-size: clamp(1.7rem, 3.2vw, 2.3rem);
    margin: 0;
    text-wrap: balance;
  }

  .detail-author { color: var(--ink-soft); margin: 0; font-size: 1.15rem; }

  .stars { color: var(--accent); letter-spacing: 0.08em; font-size: 1.5rem; }
  .stars .empty { color: var(--ink-faint); }

  .rating-line {
    display: flex;
    align-items: baseline;
    gap: 0.6rem;
  }

  .rating-meta {
    color: var(--ink-faint);
    font-size: 1rem;
    font-variant-numeric: tabular-nums;
  }

  .meta-date {
    color: var(--ink-faint);
    font-size: 0.8rem;
    margin: 0.2rem 0 0;
    font-variant-numeric: tabular-nums;
  }

  .meta-owner {
    color: var(--ink-faint);
    font-size: 0.8rem;
    margin: 0.15rem 0 0;
  }

  .btn-ghost-danger {
    background: none;
    border: 1px solid var(--line);
    color: var(--ink-faint);
    border-radius: 3px;
    padding: 0.5rem 0.9rem;
    font-family: inherit;
    font-size: 0.85rem;
    cursor: pointer;
    margin-top: 0.5rem;
  }

  .btn-ghost-danger:hover { border-color: var(--accent); color: var(--accent); }

  .comments {
    margin-top: 2.25rem;
  }

  .comments h3 {
    font-family: "Gowun Batang", serif;
    font-weight: 700;
    font-size: 1.05rem;
    margin: 0 0 0.9rem;
  }

  .comments h3 .count {
    color: var(--ink-faint);
    font-weight: 400;
    font-size: 0.85rem;
  }

  #commentList {
    list-style: none;
    margin: 0 0 1.1rem;
    padding: 0;
  }

  #commentList li {
    display: flex;
    align-items: baseline;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 0.4rem 1rem;
    padding: 0.6rem 0;
    border-bottom: 1px solid var(--line);
    font-size: 0.95rem;
  }

  #commentList .c-text {
    flex: 1 1 100%;
    min-width: 0;
    word-break: break-word;
  }

  #commentList .c-rating {
    flex: none;
    color: var(--accent);
    font-size: 0.78rem;
    letter-spacing: 0.04em;
  }

  #commentList .c-author {
    flex: none;
    color: var(--ink-faint);
    font-size: 0.78rem;
  }

  #commentList .c-like {
    flex: none;
    display: flex;
    align-items: center;
    gap: 0.3rem;
    background: none;
    border: 1px solid var(--line);
    border-radius: 999px;
    padding: 0.15rem 0.6rem;
    font-family: inherit;
    font-size: 0.78rem;
    color: var(--ink-faint);
    cursor: pointer;
    font-variant-numeric: tabular-nums;
    transition: color 0.15s ease, border-color 0.15s ease;
  }

  #commentList .c-like:hover { border-color: var(--accent); color: var(--accent); }

  #commentList .c-like.liked {
    color: var(--accent);
    border-color: var(--accent);
  }

  #commentList .c-date {
    flex: none;
    color: var(--ink-faint);
    font-size: 0.75rem;
    font-variant-numeric: tabular-nums;
  }

  #commentList .c-del {
    flex: none;
    background: none;
    border: none;
    color: var(--ink-faint);
    cursor: pointer;
    font-size: 0.85rem;
    padding: 0 0.2rem;
  }

  #commentList .c-del:hover { color: var(--accent); }

  #commentForm {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
  }

  #commentForm .field {
    margin-bottom: 0;
  }

  #commentForm .field label {
    font-size: 0.78rem;
    margin-bottom: 0.15rem;
  }

  .comment-input-row {
    display: flex;
    gap: 0.6rem;
  }

  #commentInput {
    flex: 1;
    font-family: inherit;
    font-size: 0.95rem;
    color: var(--ink);
    background: var(--paper-raised);
    border: 1px solid var(--line);
    border-radius: 3px;
    padding: 0.55rem 0.7rem;
  }

  .comment-input-row button {
    background: var(--accent);
    color: var(--paper-raised);
    border: none;
    border-radius: 3px;
    padding: 0 1rem;
    font-family: inherit;
    cursor: pointer;
  }

  .comment-input-row button:hover { background: var(--accent-soft); }

  .char-hint {
    font-size: 0.72rem;
    color: var(--ink-faint);
    margin: 0.35rem 0 0;
  }

  .tagline-note {
    margin: 0.3rem 0 0;
    color: var(--ink-faint);
    font-size: 0.78rem;
  }

  /* random pick */

  .random-panel { text-align: center; }
  .random-panel h2 { text-align: left; }
  .random-panel .char-hint { text-align: left; margin-top: -0.6rem; }

  .random-stage {
    display: flex;
    justify-content: center;
    padding: 1.75rem 0 0.5rem;
  }

  .random-card {
    width: clamp(220px, 40vw, 320px);
    max-width: 80vw;
    border-radius: 8px;
    overflow: hidden;
    background: var(--paper-soft);
    box-shadow: 0 8px 22px var(--shadow);
  }

  .random-card-cover {
    position: relative;
    aspect-ratio: 2 / 3;
    background: var(--cover, var(--accent));
  }

  .random-card-cover img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
  }

  .random-card-title {
    min-height: 3.2em;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 0.9rem;
    background: var(--paper-raised);
    font-family: "Gowun Batang", serif;
    font-size: 1.15rem;
    line-height: 1.35;
    text-align: center;
    color: var(--ink);
  }

  .random-card.spinning {
    animation: randomShake 0.12s linear infinite;
  }

  @keyframes randomShake {
    0% { transform: translateY(0) rotate(0deg); }
    50% { transform: translateY(-2px) rotate(-0.6deg); }
    100% { transform: translateY(0) rotate(0.6deg); }
  }

  .random-info { margin-top: 0.75rem; }

  .random-info h3 {
    font-family: "Gowun Batang", serif;
    font-size: 1.35rem;
    margin: 0 0 0.3rem;
    text-wrap: balance;
  }

  .random-info-review {
    margin: 1rem auto 0;
    max-width: 480px;
    padding: 0.9rem 1.1rem;
    background: var(--paper-soft);
    border-left: 3px solid var(--accent);
    border-radius: 3px;
    font-size: 0.95rem;
    color: var(--ink);
    text-align: left;
  }

  .random-actions { justify-content: center; }

  [hidden] { display: none !important; }