/* ─────────────────────────────────────────────────────────────
   theme-book.css — 千序写作 全站「明亮书卷风」视觉规范
   本文件只定义 --bk-* 新增变量与 .bk-* 新增组件类，
   不修改任何页面的原有变量与原有类名，原有样式 100% 保留。
   ------------------------------------------------------------- */

:root {
  /* 书卷风中性色 */
  --bk-paper: #FAF8F5;        /* 暖白纸感背景 */
  --bk-paper-2: #F3F0EA;      /* 次级纸感背景 */
  --bk-card: #FFFFFF;         /* 卡片面 */
  --bk-ink: #0F172A;          /* 标题墨蓝 */
  --bk-body: #334155;         /* 正文 */
  --bk-muted: #64748B;        /* 元信息 / 次要文字 */
  --bk-border: rgba(15, 23, 42, .10);   /* 边框 */

  /* 品牌强调（沿用现有主青，全站统一） */
  --bk-brand: #06b6d4;
  --bk-brand-deep: #0E7490;
  --bk-brand-soft: rgba(6, 182, 212, .10);
  --bk-brand-border: rgba(6, 182, 212, .28);

  /* 暖金：仅用于付费 / 精选角标 */
  --bk-gold: #F0B429;
  --bk-gold-deep: #C98A1B;
  --bk-gold-soft: rgba(240, 180, 41, .14);
  --bk-gold-border: rgba(240, 180, 41, .40);

  /* 圆角 / 阴影 / 间距 */
  --bk-radius: 18px;
  --bk-radius-sm: 12px;
  --bk-radius-cover: 14px;
  --bk-radius-full: 999px;
  --bk-shadow-1: 0 1px 2px rgba(15, 23, 42, .06);
  --bk-shadow-2: 0 8px 24px rgba(15, 23, 42, .08);
  --bk-shadow-3: 0 16px 40px rgba(15, 23, 42, .12);
  --bk-gap: 24px;
  --bk-gap-sm: 16px;

  /* 封面渐变色板（12 组，按 kb.id 稳定派生） */
  --bk-cover-1:  linear-gradient(135deg, #1F2937 0%, #3B4A5F 60%, #06b6d4 160%);
  --bk-cover-2:  linear-gradient(135deg, #134E4A 0%, #0F766E 55%, #14B8A6 130%);
  --bk-cover-3:  linear-gradient(135deg, #1E1B4B 0%, #312E81 60%, #818CF8 150%);
  --bk-cover-4:  linear-gradient(135deg, #78350F 0%, #B45309 60%, #F59E0B 140%);
  --bk-cover-5:  linear-gradient(135deg, #4C0519 0%, #9F1239 60%, #FB7185 150%);
  --bk-cover-6:  linear-gradient(135deg, #0C4A6E 0%, #0369A1 60%, #38BDF8 140%);
  --bk-cover-7:  linear-gradient(135deg, #14532D 0%, #15803D 60%, #4ADE80 140%);
  --bk-cover-8:  linear-gradient(135deg, #312E81 0%, #6D28D9 60%, #C4B5FD 150%);
  --bk-cover-9:  linear-gradient(135deg, #831843 0%, #DB2777 60%, #F9A8D4 150%);
  --bk-cover-10: linear-gradient(135deg, #111827 0%, #334155 60%, #94A3B8 150%);
  --bk-cover-11: linear-gradient(135deg, #164E63 0%, #155E75 60%, #22D3EE 140%);
  --bk-cover-12: linear-gradient(135deg, #581C87 0%, #7E22CE 60%, #D8B4FE 150%);
}

[data-theme="dark"] {
  --bk-paper: #0B1220;
  --bk-paper-2: #101A2C;
  --bk-card: #131E33;
  --bk-ink: #E8EDF5;
  --bk-body: #C3CBD8;
  --bk-muted: #8494AB;
  --bk-border: rgba(148, 163, 184, .16);
  --bk-brand-soft: rgba(6, 182, 212, .14);
  --bk-brand-border: rgba(6, 182, 212, .36);
  --bk-gold-soft: rgba(240, 180, 41, .16);
  --bk-gold-border: rgba(240, 180, 41, .46);
  --bk-shadow-1: 0 1px 2px rgba(0, 0, 0, .30);
  --bk-shadow-2: 0 8px 24px rgba(0, 0, 0, .40);
  --bk-shadow-3: 0 16px 40px rgba(0, 0, 0, .55);
}

/* ── 通用工具 ─────────────────────────────────────────── */
.bk-muted { color: var(--bk-muted) !important; }
.bk-body  { color: var(--bk-body) !important; }
.bk-ink   { color: var(--bk-ink) !important; }
.bk-brand-text { color: var(--bk-brand) !important; }

/* ── 分区容器 ─────────────────────────────────────────── */
.bk-section {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--bk-gap);
}
.bk-section-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--bk-gap-sm);
  margin: var(--bk-gap) 0 var(--bk-gap-sm);
}
.bk-section-title {
  font-size: 22px;
  font-weight: 700;
  color: var(--bk-ink);
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0;
}
.bk-section-title .bk-mark {
  width: 6px;
  height: 22px;
  border-radius: var(--bk-radius-full);
  background: var(--bk-brand);
  flex-shrink: 0;
}
.bk-section-more {
  font-size: 13px;
  color: var(--bk-muted);
  text-decoration: none;
  white-space: nowrap;
  transition: color .2s;
}
.bk-section-more:hover { color: var(--bk-brand); }

/* ── 封面 ─────────────────────────────────────────────── */
.bk-cover {
  position: relative;
  border-radius: var(--bk-radius-cover);
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  isolation: isolate;
}
.bk-cover-ratio { aspect-ratio: 16 / 10; }
.bk-cover .bk-cover-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  transition: transform .25s ease;
}
.bk-cover .bk-cover-icon {
  color: rgba(255, 255, 255, .96);
  filter: drop-shadow(0 2px 6px rgba(0, 0, 0, .25));
  transition: transform .25s ease;
}
.bk-cover::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, transparent 62%, rgba(0, 0, 0, .28));
  pointer-events: none;
}
/* 付费角标（覆盖在封面上） */
.bk-price-badge {
  position: absolute;
  top: 12px;
  right: 12px;
  z-index: 2;
  padding: 3px 10px;
  border-radius: var(--bk-radius-full);
  background: var(--bk-gold);
  color: #fff;
  font-size: 12px;
  font-weight: 700;
  box-shadow: 0 2px 8px rgba(0, 0, 0, .22);
}
.bk-free-badge {
  position: absolute;
  top: 12px;
  right: 12px;
  z-index: 2;
  padding: 3px 10px;
  border-radius: var(--bk-radius-full);
  background: rgba(255, 255, 255, .92);
  color: var(--bk-muted);
  font-size: 12px;
  font-weight: 600;
  box-shadow: 0 2px 8px rgba(0, 0, 0, .16);
}

/* ── 知识库卡片（升级版） ─────────────────────────────── */
.bk-kb-card {
  background: var(--bk-card);
  border: 1px solid var(--bk-border);
  border-radius: var(--bk-radius);
  overflow: hidden;
  cursor: pointer;
  position: relative;
  transition: transform .22s ease, box-shadow .22s ease, border-color .22s ease;
  box-shadow: var(--bk-shadow-1);
}
.bk-kb-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--bk-shadow-2);
  border-color: var(--bk-brand-border);
}
.bk-kb-card:hover .bk-cover-img,
.bk-kb-card:hover .bk-cover-icon { transform: scale(1.04); }
.bk-kb-card-body { padding: var(--bk-gap-sm); }
.bk-kb-card-name {
  font-size: 15px;
  font-weight: 700;
  color: var(--bk-ink);
  margin: 0 0 4px;
  display: -webkit-box;
  -webkit-line-clamp: 1;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.bk-kb-card-desc {
  font-size: 12.5px;
  color: var(--bk-muted);
  line-height: 1.55;
  margin: 0 0 10px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  min-height: 38px;
}
.bk-kb-card-meta {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
  font-size: 12px;
  color: var(--bk-muted);
  padding-top: 10px;
  border-top: 1px solid var(--bk-border);
}
.bk-kb-card-meta .bk-author {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  min-width: 0;
}
.bk-kb-card-meta .bk-author-avatar {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  flex-shrink: 0;
  background: var(--bk-brand-soft);
  color: var(--bk-brand);
  font-size: 11px;
  font-weight: 700;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}
.bk-kb-card-meta .bk-dot { opacity: .45; }
.bk-kb-card-actions {
  display: flex;
  gap: 8px;
  margin-top: 12px;
}
.bk-kb-card-actions .bk-btn { flex: 1; }

/* 已订阅态（沿用原 .kb-card.subscribed 的强调语义，仅样式） */
.bk-kb-card.bk-subscribed { border-color: var(--bk-brand-border); }

/* 文件卡片矮封面 */
.bk-cover-file { height: 96px; }

/* 分组标题（搜索结果区/全部列表区的「📄 匹配文件」「📚 匹配知识库」） */
.bk-grid-title {
  margin: 20px 0 10px;
  color: var(--bk-muted);
  font-size: 13px;
  font-weight: 600;
}

/* ── 按钮 ─────────────────────────────────────────────── */
.bk-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 5px;
  padding: 9px 0;
  border: none;
  border-radius: 10px;
  font-size: 13px;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: all .2s;
  text-decoration: none;
}
.bk-btn-primary {
  background: var(--bk-brand);
  color: #fff;
}
.bk-btn-primary:hover { box-shadow: 0 6px 18px rgba(6, 182, 212, .30); }
.bk-btn-primary:disabled { opacity: .5; cursor: not-allowed; box-shadow: none; }
.bk-btn-ghost {
  background: transparent;
  color: var(--bk-body);
  border: 1px solid var(--bk-border);
}
.bk-btn-ghost:hover { border-color: var(--bk-brand-border); color: var(--bk-brand); }
.bk-btn-gold {
  background: var(--bk-gold);
  color: #fff;
}
.bk-btn-gold:hover { box-shadow: 0 6px 18px rgba(240, 180, 41, .34); }
.bk-btn-gold:disabled { opacity: .5; cursor: not-allowed; box-shadow: none; }
.bk-btn-buy {
  background: var(--bk-gold);
  color: #fff;
}
.bk-btn-buy:hover { box-shadow: 0 6px 18px rgba(240, 180, 41, .34); }
.bk-btn-buy:disabled { opacity: .5; cursor: not-allowed; box-shadow: none; }
.bk-btn-subscribed {
  background: var(--bk-brand-soft);
  color: var(--bk-brand-deep);
  border: 1px solid var(--bk-brand-border);
}
.bk-btn-unsub {
  background: transparent;
  color: var(--bk-muted);
  border: 1px solid var(--bk-border);
  font-size: 12px;
}
.bk-btn-unsub:hover {
  background: rgba(239, 68, 68, .08);
  border-color: rgba(239, 68, 68, .3);
  color: #ef4444;
}

/* ── 分类入口条（图标 + 名称） ───────────────────────── */
.bk-cat-strip {
  display: flex;
  gap: 12px;
  overflow-x: auto;
  padding: 4px 2px 12px;
  scrollbar-width: none;
}
.bk-cat-strip::-webkit-scrollbar { display: none; }
.bk-cat-pill {
  flex-shrink: 0;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 9px 16px;
  border-radius: var(--bk-radius-full);
  background: var(--bk-card);
  border: 1px solid var(--bk-border);
  color: var(--bk-body);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  font-family: inherit;
  transition: all .2s;
  box-shadow: var(--bk-shadow-1);
}
.bk-cat-pill:hover {
  border-color: var(--bk-brand-border);
  color: var(--bk-brand);
  transform: translateY(-1px);
}
.bk-cat-pill.active {
  background: var(--bk-brand);
  color: #fff;
  border-color: transparent;
}
.bk-cat-pill .bk-cat-icon {
  width: 22px;
  height: 22px;
  border-radius: 7px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  flex-shrink: 0;
}

/* ── 横滑内容行 ───────────────────────────────────────── */
.bk-shelf {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: 240px;
  gap: var(--bk-gap-sm);
  overflow-x: auto;
  padding: 4px 2px 14px;
  scrollbar-width: none;
}
.bk-shelf::-webkit-scrollbar { display: none; }
.bk-shelf .bk-kb-card { width: 100%; }
@media (max-width: 768px) {
  .bk-shelf { grid-auto-columns: 78vw; }
}

/* ── 分类网格容器（承载原有 .kb-grid 的位置，纯样式覆盖） ── */
.bk-kb-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--bk-gap-sm);
  padding: 0 var(--bk-gap);
}

/* ── Hero：左文案 + 右主推大卡 ───────────────────────── */
.bk-hero {
  position: relative;
  overflow: hidden;
  padding: 72px var(--bk-gap) 48px;
  background: var(--bk-paper);
}
.bk-hero-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1.1fr .9fr;
  gap: 48px;
  align-items: center;
}
.bk-hero-left { position: relative; z-index: 2; }
.bk-hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  border-radius: var(--bk-radius-full);
  background: var(--bk-brand-soft);
  border: 1px solid var(--bk-brand-border);
  color: var(--bk-brand-deep);
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 18px;
}
[data-theme="dark"] .bk-hero-badge { color: #67E8F9; }
.bk-hero-title {
  font-size: clamp(30px, 4.6vw, 46px);
  font-weight: 800;
  line-height: 1.22;
  color: var(--bk-ink);
  letter-spacing: -1px;
  margin: 0 0 14px;
}
.bk-hero-title .bk-hero-accent {
  color: var(--bk-brand);
}
.bk-hero-sub {
  font-size: 15px;
  color: var(--bk-muted);
  line-height: 1.75;
  max-width: 480px;
  margin: 0 0 26px;
}
.bk-hero-stats {
  display: flex;
  gap: 30px;
  margin-bottom: 28px;
}
.bk-hero-stats .stat { text-align: left; }
.bk-hero-stats .num {
  font-size: 26px;
  font-weight: 800;
  color: var(--bk-ink);
  line-height: 1.1;
  font-variant-numeric: tabular-nums;
}
.bk-hero-stats .label { font-size: 12.5px; color: var(--bk-muted); margin-top: 2px; }
.bk-hero-cta {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}
.bk-hero-cta .bk-btn { padding: 12px 26px; font-size: 14px; }
/* 主推大卡 */
.bk-hero-card {
  position: relative;
  z-index: 2;
  background: var(--bk-card);
  border: 1px solid var(--bk-border);
  border-radius: var(--bk-radius);
  overflow: hidden;
  box-shadow: var(--bk-shadow-3);
  cursor: pointer;
  transition: transform .25s ease, box-shadow .25s ease;
}
.bk-hero-card:hover { transform: translateY(-4px); }
.bk-hero-card .bk-cover-ratio { aspect-ratio: 16 / 10; }
.bk-hero-card .bk-kb-card-body { padding: var(--bk-gap); }
.bk-hero-card .bk-kb-card-name { font-size: 19px; }
.bk-hero-card .bk-kb-card-desc { font-size: 13.5px; min-height: 0; }
.bk-hero-card-tag {
  position: absolute;
  top: 14px;
  left: 14px;
  z-index: 2;
  padding: 4px 12px;
  border-radius: var(--bk-radius-full);
  background: rgba(255, 255, 255, .92);
  color: var(--bk-ink);
  font-size: 12px;
  font-weight: 700;
  box-shadow: 0 2px 8px rgba(0, 0, 0, .16);
}
/* 装饰光斑（纯装饰，不影响布局） */
.bk-hero::before {
  content: '';
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(ellipse 520px 340px at 12% 30%, rgba(6, 182, 212, .08), transparent),
    radial-gradient(ellipse 420px 300px at 86% 20%, rgba(240, 180, 41, .07), transparent);
}
@media (max-width: 900px) {
  .bk-hero { padding: 56px var(--bk-gap) 40px; }
  .bk-hero-inner { grid-template-columns: 1fr; gap: 32px; }
  .bk-hero-card { max-width: 520px; }
  .bk-hero-stats { gap: 22px; }
}

/* ── 骨架屏 ───────────────────────────────────────────── */
.bk-skeleton {
  position: relative;
  overflow: hidden;
  background: var(--bk-paper-2);
}
.bk-skeleton::after {
  content: '';
  position: absolute;
  inset: 0;
  transform: translateX(-100%);
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, .5), transparent);
  animation: bk-shimmer 1.4s infinite;
}
[data-theme="dark"] .bk-skeleton::after {
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, .07), transparent);
}
@keyframes bk-shimmer { 100% { transform: translateX(100%); } }

/* 入场动效（尊重系统减弱动态设置） */
@media (prefers-reduced-motion: no-preference) {
  .bk-fade-in {
    opacity: 0;
    animation: bk-fade-up .5s ease forwards;
  }
  @keyframes bk-fade-up {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
  }
}

/* ── 运营区（底部合并区块） ──────────────────────────── */
.bk-ops {
  max-width: 1200px;
  margin: 48px auto 0;
  padding: 0 var(--bk-gap);
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--bk-gap);
}
.bk-ops-card {
  background: var(--bk-card);
  border: 1px solid var(--bk-border);
  border-radius: var(--bk-radius);
  box-shadow: var(--bk-shadow-1);
  display: flex;
  align-items: center;
  gap: 20px;
  padding: 24px 28px;
}
.bk-ops-card .bk-ops-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--bk-radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 28px;
  flex-shrink: 0;
  background: var(--bk-brand-soft);
}
.bk-ops-card .bk-ops-icon.qr {
  background: #fff;
  border: 1px solid var(--bk-border);
  padding: 5px;
}
.bk-ops-card .bk-ops-icon.qr img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  border-radius: 6px;
}
.bk-ops-card h3 { font-size: 16px; font-weight: 700; color: var(--bk-ink); margin: 0 0 4px; }
.bk-ops-card p { font-size: 13px; color: var(--bk-muted); margin: 0 0 10px; }
.bk-ops-link {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 13px;
  font-weight: 600;
  color: var(--bk-brand);
  text-decoration: none;
}
.bk-ops-link:hover { color: var(--bk-brand-deep); }
@media (max-width: 768px) {
  .bk-ops { grid-template-columns: 1fr; }
  .bk-ops-card { flex-direction: column; text-align: center; }
}