/* ========================================
   我的脑海便利店 · 原木知识书房
   榉木原木色极简高级风
   ======================================== */

:root {
  /* 主色板 */
  --color-primary: #3F3126;
  --color-beech: #C89F6D;
  --color-beech-dark: #A67E4E;
  --color-bg: #F7F1E8;
  --color-card: #FFFBF5;
  --color-wood-light: #E8D2B4;
  --color-wood-mid: #D4B896;
  --color-text: #5E5146;
  --color-text-muted: #9A8B7B;
  --color-hover: #8B6238;
  --color-line: #E6E0D6;
  --color-hover-bg: #EFEBE3;
  --color-white: #FFFFFF;

  /* 间距 */
  --space-xs: 8px;
  --space-sm: 16px;
  --space-md: 24px;
  --space-lg: 40px;
  --space-xl: 64px;
  --space-2xl: 96px;

  /* 圆角 */
  --radius: 16px;
  --radius-lg: 22px;
  --radius-sm: 10px;

  /* 阴影 */
  --shadow-sm: 0 1px 3px rgba(63, 49, 38, 0.06);
  --shadow-md: 0 4px 14px rgba(63, 49, 38, 0.08);
  --shadow-lg: 0 10px 30px rgba(63, 49, 38, 0.12);
  --shadow-book: 0 6px 16px rgba(63, 49, 38, 0.15), 0 2px 4px rgba(63, 49, 38, 0.08);

  /* 容器 */
  --container: 1080px;

  /* 字体 */
  --font-sans: -apple-system, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
  --font-serif: "Noto Serif SC", "Songti SC", "SimSun", serif;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

/* ==================== 导航 ==================== */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding: 18px 0;
  transition: all 0.3s ease;
  background: rgba(247, 241, 232, 0);
  backdrop-filter: blur(0px);
}
.nav.scrolled {
  padding: 12px 0;
  background: rgba(247, 241, 232, 0.85);
  backdrop-filter: blur(12px);
  box-shadow: 0 1px 0 var(--color-line);
}
.nav-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--space-md);
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-logo {
  font-size: 18px;
  font-weight: 700;
  color: var(--color-primary);
  letter-spacing: 1px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.nav-logo .logo-icon {
  width: 32px; height: 32px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--color-beech), var(--color-beech-dark));
  display: flex; align-items: center; justify-content: center;
  font-size: 16px;
  color: #fff;
}
.nav-links {
  display: flex;
  gap: 32px;
  list-style: none;
}
.nav-links a {
  font-size: 15px;
  color: var(--color-text);
  font-weight: 500;
  position: relative;
  padding: 4px 0;
  transition: color 0.2s;
}
.nav-links a:hover { color: var(--color-hover); }
.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px; left: 0;
  width: 0; height: 2px;
  background: var(--color-beech);
  transition: width 0.3s ease;
}
.nav-links a:hover::after { width: 100%; }
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
}
.nav-toggle span {
  width: 24px; height: 2px;
  background: var(--color-primary);
  border-radius: 2px;
  transition: all 0.3s;
}
.nav-toggle.open span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

/* ==================== Hero ==================== */
.hero {
  min-height: 90vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 120px var(--space-md) var(--space-2xl);
  position: relative;
}
.hero::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background:
    radial-gradient(ellipse at 50% 30%, rgba(200, 159, 109, 0.08) 0%, transparent 60%),
    radial-gradient(ellipse at 80% 70%, rgba(232, 210, 180, 0.06) 0%, transparent 50%);
  pointer-events: none;
}
.hero-content { position: relative; z-index: 1; max-width: 720px; }
.hero h1 {
  font-family: var(--font-serif);
  font-size: clamp(36px, 6vw, 56px);
  font-weight: 800;
  color: var(--color-primary);
  letter-spacing: 2px;
  margin-bottom: var(--space-md);
  line-height: 1.3;
}
.hero .tagline {
  font-size: clamp(16px, 2.5vw, 20px);
  color: var(--color-beech-dark);
  font-weight: 600;
  margin-bottom: var(--space-sm);
  letter-spacing: 1px;
}
.hero .desc {
  font-size: 16px;
  color: var(--color-text-muted);
  line-height: 2;
  margin-bottom: var(--space-lg);
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
}
.hero-buttons {
  display: flex;
  gap: var(--space-sm);
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: var(--space-xl);
}
.btn-primary {
  padding: 14px 32px;
  background: var(--color-primary);
  color: #fff;
  border-radius: var(--radius-sm);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 1px;
  transition: all 0.3s;
  border: none;
  cursor: pointer;
  box-shadow: var(--shadow-md);
}
.btn-primary:hover {
  background: var(--color-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}
.btn-secondary {
  padding: 14px 32px;
  background: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-wood-light);
  border-radius: var(--radius-sm);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 1px;
  transition: all 0.3s;
  cursor: pointer;
}
.btn-secondary:hover {
  border-color: var(--color-beech);
  background: var(--color-hover-bg);
  transform: translateY(-2px);
}
.hero-stats {
  display: flex;
  gap: 40px;
  justify-content: center;
  flex-wrap: wrap;
}
.hero-stat {
  text-align: center;
}
.hero-stat .num {
  font-size: 28px;
  font-weight: 800;
  color: var(--color-beech-dark);
  font-family: var(--font-serif);
}
.hero-stat .label {
  font-size: 13px;
  color: var(--color-text-muted);
  margin-top: 4px;
}

/* ==================== 通用 Section ==================== */
.section {
  max-width: var(--container);
  margin: 0 auto;
  padding: var(--space-xl) var(--space-md);
}
.section-header {
  text-align: center;
  margin-bottom: var(--space-lg);
}
.section-header h2 {
  font-family: var(--font-serif);
  font-size: clamp(26px, 4vw, 34px);
  color: var(--color-primary);
  font-weight: 700;
  margin-bottom: var(--space-sm);
  letter-spacing: 1px;
}
.section-header p {
  font-size: 15px;
  color: var(--color-text-muted);
  max-width: 480px;
  margin: 0 auto;
}
.section-divider {
  width: 48px; height: 3px;
  background: var(--color-beech);
  border-radius: 2px;
  margin: var(--space-sm) auto 0;
}

/* ==================== 三大入口 ==================== */
.entries {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-md);
}
.entry-card {
  background: var(--color-card);
  border-radius: var(--radius-lg);
  padding: var(--space-lg) var(--space-md);
  text-align: center;
  border: 1px solid var(--color-line);
  transition: all 0.35s ease;
  cursor: pointer;
  position: relative;
  overflow: hidden;
}
.entry-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--color-beech), var(--color-beech-dark));
  opacity: 0;
  transition: opacity 0.3s;
}
.entry-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-wood-light);
}
.entry-card:hover::before { opacity: 1; }
.entry-icon {
  width: 56px; height: 56px;
  margin: 0 auto var(--space-sm);
  border-radius: 14px;
  background: linear-gradient(135deg, rgba(200, 159, 109, 0.15), rgba(200, 159, 109, 0.05));
  display: flex; align-items: center; justify-content: center;
  font-size: 26px;
}
.entry-card h3 {
  font-size: 18px;
  color: var(--color-primary);
  font-weight: 700;
  margin-bottom: var(--space-xs);
}
.entry-card p {
  font-size: 14px;
  color: var(--color-text-muted);
  line-height: 1.8;
}

/* ==================== 精选书架 ==================== */
.featured-books {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: var(--space-md);
}
.book-card {
  background: var(--color-card);
  border-radius: var(--radius);
  padding: var(--space-md);
  border: 1px solid var(--color-line);
  transition: all 0.35s ease;
  cursor: pointer;
  position: relative;
  display: flex;
  flex-direction: column;
}
.book-card::after {
  content: '';
  position: absolute;
  left: var(--space-md); right: var(--space-md);
  bottom: -1px;
  height: 3px;
  background: linear-gradient(90deg, transparent, var(--color-wood-mid), transparent);
  border-radius: 2px;
  opacity: 0;
  transition: opacity 0.3s;
}
.book-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-book);
  border-color: var(--color-wood-light);
}
.book-card:hover::after { opacity: 1; }
.book-tag {
  display: inline-block;
  font-size: 12px;
  color: var(--color-beech-dark);
  background: rgba(200, 159, 109, 0.1);
  padding: 3px 10px;
  border-radius: 20px;
  margin-bottom: var(--space-sm);
  align-self: flex-start;
}
.book-card h3 {
  font-size: 18px;
  color: var(--color-primary);
  font-weight: 700;
  margin-bottom: 6px;
  line-height: 1.4;
}
.book-card .book-subtitle {
  font-size: 13px;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}
.book-card .book-scale {
  font-size: 13px;
  color: var(--color-beech-dark);
  margin-top: auto;
  padding-top: var(--space-sm);
  border-top: 1px solid var(--color-line);
  font-weight: 500;
}
.book-arrow {
  font-size: 14px;
  color: var(--color-beech);
  margin-left: 4px;
}

/* ==================== 最近更新 ==================== */
.updates-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  max-width: 640px;
  margin: 0 auto;
}
.update-item {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-sm) var(--space-md);
  background: var(--color-card);
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-line);
  transition: all 0.3s;
}
.update-item:hover {
  border-color: var(--color-wood-light);
  box-shadow: var(--shadow-sm);
}
.update-date {
  font-size: 13px;
  color: var(--color-beech-dark);
  font-weight: 600;
  white-space: nowrap;
  min-width: 80px;
}
.update-tag {
  font-size: 12px;
  color: var(--color-text-muted);
  background: var(--color-hover-bg);
  padding: 2px 8px;
  border-radius: 6px;
  white-space: nowrap;
}
.update-title {
  font-size: 14px;
  color: var(--color-text);
  font-weight: 500;
}

/* ==================== 关于 ==================== */
.about-section {
  text-align: center;
  background: var(--color-card);
  border-radius: var(--radius-lg);
  padding: var(--space-xl) var(--space-md);
  border: 1px solid var(--color-line);
}
.about-avatar {
  width: 80px; height: 80px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-beech), var(--color-beech-dark));
  margin: 0 auto var(--space-md);
  display: flex; align-items: center; justify-content: center;
  font-size: 32px;
  color: #fff;
  cursor: pointer;
  overflow: hidden;
  position: relative;
  transition: all 0.3s;
  border: 3px solid var(--color-white);
  box-shadow: var(--shadow-md);
}
.about-avatar:hover { transform: scale(1.05); }
.about-avatar img {
  width: 100%; height: 100%;
  object-fit: cover;
}
.about-avatar .avatar-placeholder {
  font-size: 32px;
}
.about-avatar input {
  position: absolute;
  width: 100%; height: 100%;
  opacity: 0;
  cursor: pointer;
}
.about-name {
  font-size: 20px;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: var(--space-xs);
}
.about-bio {
  font-size: 14px;
  color: var(--color-text-muted);
  line-height: 2;
  max-width: 400px;
  margin: 0 auto;
}
.about-tags {
  display: flex;
  gap: var(--space-xs);
  justify-content: center;
  flex-wrap: wrap;
  margin-top: var(--space-md);
}
.about-tag {
  font-size: 13px;
  color: var(--color-beech-dark);
  background: rgba(200, 159, 109, 0.08);
  padding: 4px 12px;
  border-radius: 20px;
  border: 1px solid rgba(200, 159, 109, 0.2);
}

/* ==================== Footer ==================== */
.footer {
  text-align: center;
  padding: var(--space-xl) var(--space-md) var(--space-lg);
  border-top: 1px solid var(--color-line);
  margin-top: var(--space-xl);
}
.footer-stats {
  display: flex;
  gap: 48px;
  justify-content: center;
  margin-bottom: var(--space-md);
}
.footer-stat {
  text-align: center;
}
.footer-stat .icon { font-size: 24px; margin-bottom: 6px; }
.footer-stat .num {
  font-size: 22px;
  font-weight: 700;
  color: var(--color-primary);
}
.footer-stat .label { font-size: 13px; color: var(--color-text-muted); }
.like-btn {
  background: var(--color-card);
  border: 2px solid var(--color-wood-light);
  border-radius: 30px;
  padding: 10px 24px;
  font-size: 14px;
  color: var(--color-primary);
  cursor: pointer;
  transition: all 0.3s;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.like-btn:hover {
  border-color: var(--color-beech);
  background: var(--color-hover-bg);
}
.like-btn.liked {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}
.footer-wechat {
  font-size: 13px;
  color: var(--color-text-muted);
  margin-top: var(--space-md);
}
.footer-copy {
  font-size: 12px;
  color: var(--color-text-muted);
  margin-top: var(--space-lg);
  padding-top: var(--space-md);
  border-top: 1px solid var(--color-line);
}

/* ==================== 科普馆·书架 ==================== */
.science-hero {
  padding: 120px var(--space-md) var(--space-lg);
  text-align: center;
}
.science-hero h1 {
  font-family: var(--font-serif);
  font-size: clamp(32px, 5vw, 44px);
  color: var(--color-primary);
  font-weight: 800;
  margin-bottom: var(--space-sm);
  letter-spacing: 2px;
}
.science-hero p {
  font-size: 16px;
  color: var(--color-text-muted);
  max-width: 480px;
  margin: 0 auto;
}

/* 搜索 + 分类 */
.shelf-controls {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--space-md) var(--space-lg);
}
.search-box {
  position: relative;
  max-width: 400px;
  margin: 0 auto var(--space-md);
}
.search-box input {
  width: 100%;
  padding: 12px 20px 12px 44px;
  border: 1px solid var(--color-line);
  border-radius: 30px;
  font-size: 14px;
  background: var(--color-card);
  color: var(--color-text);
  outline: none;
  transition: border-color 0.3s;
  font-family: var(--font-sans);
}
.search-box input:focus { border-color: var(--color-beech); }
.search-box input::placeholder { color: var(--color-text-muted); }
.search-box .search-icon {
  position: absolute;
  left: 16px; top: 50%;
  transform: translateY(-50%);
  font-size: 16px;
  color: var(--color-text-muted);
}
.category-tabs {
  display: flex;
  gap: var(--space-xs);
  justify-content: center;
  flex-wrap: wrap;
}
.cat-tab {
  padding: 8px 18px;
  border-radius: 20px;
  font-size: 14px;
  color: var(--color-text);
  background: var(--color-card);
  border: 1px solid var(--color-line);
  cursor: pointer;
  transition: all 0.25s;
  font-family: var(--font-sans);
  font-weight: 500;
}
.cat-tab:hover {
  border-color: var(--color-wood-light);
  color: var(--color-hover);
}
.cat-tab.active {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

/* 书架主体 */
.bookshelf {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--space-md) var(--space-2xl);
}
.shelf-row {
  margin-bottom: var(--space-lg);
}
.shelf-category {
  font-size: 15px;
  color: var(--color-beech-dark);
  font-weight: 700;
  margin-bottom: var(--space-md);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}
.shelf-category::before {
  content: '';
  width: 4px; height: 20px;
  background: var(--color-beech);
  border-radius: 2px;
}
.shelf-books {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: var(--space-md);
  align-items: end;
  padding-bottom: var(--space-sm);
  position: relative;
}
.shelf-books::after {
  content: '';
  position: absolute;
  left: 0; right: 0; bottom: 0;
  height: 6px;
  background: linear-gradient(180deg, var(--color-wood-light), var(--color-wood-mid));
  border-radius: 3px;
  box-shadow: 0 2px 6px rgba(63, 49, 38, 0.1);
}

/* 单本书 */
.book {
  background: var(--color-card);
  border-radius: 6px 6px 2px 2px;
  padding: var(--space-md) var(--space-sm);
  text-align: center;
  cursor: pointer;
  transition: all 0.35s ease;
  position: relative;
  border: 1px solid var(--color-line);
  min-height: 200px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  overflow: hidden;
}
.book::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 5px;
  background: linear-gradient(90deg, var(--color-beech), var(--color-beech-dark));
}
.book::after {
  content: '';
  position: absolute;
  right: -3px; top: 5px; bottom: 0;
  width: 3px;
  background: linear-gradient(90deg, rgba(63,49,38,0.08), transparent);
  border-radius: 0 2px 2px 0;
}
.book:hover {
  transform: translateY(-10px);
  box-shadow: var(--shadow-book);
  border-color: var(--color-wood-light);
}
.book-tag {
  font-size: 11px;
  color: var(--color-beech-dark);
  background: rgba(200, 159, 109, 0.1);
  padding: 2px 8px;
  border-radius: 10px;
  align-self: center;
  margin-bottom: var(--space-xs);
}
.book-title {
  font-size: 17px;
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1.4;
  margin-bottom: 4px;
}
.book-subtitle {
  font-size: 12px;
  color: var(--color-text-muted);
  line-height: 1.5;
  margin-bottom: var(--space-sm);
}
.book-scale {
  font-size: 12px;
  color: var(--color-beech-dark);
  font-weight: 500;
  margin-top: auto;
  padding-top: var(--space-xs);
}
.book-spine-icon {
  font-size: 28px;
  margin: var(--space-xs) 0;
}

/* 空状态 */
.empty-shelf {
  text-align: center;
  padding: var(--space-2xl) var(--space-md);
  color: var(--color-text-muted);
  font-size: 15px;
}

/* ==================== 动画 ==================== */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}
.fade-in:nth-child(2) { transition-delay: 0.1s; }
.fade-in:nth-child(3) { transition-delay: 0.2s; }
.fade-in:nth-child(4) { transition-delay: 0.3s; }
.fade-in:nth-child(5) { transition-delay: 0.4s; }
.fade-in:nth-child(6) { transition-delay: 0.5s; }

/* ==================== 响应式 ==================== */
@media (max-width: 1024px) {
  .featured-books { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 100%; left: 0; right: 0;
    flex-direction: column;
    background: rgba(247, 241, 232, 0.97);
    backdrop-filter: blur(12px);
    padding: var(--space-md);
    gap: var(--space-sm);
    box-shadow: 0 4px 12px rgba(63, 49, 38, 0.08);
  }
  .nav-links.open { display: flex; }
  .nav-toggle { display: flex; }

  .hero { min-height: 80vh; padding-top: 100px; }
  .hero-stats { gap: 24px; }
  .hero-stat .num { font-size: 22px; }

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

  .featured-books { grid-template-columns: 1fr 1fr; }

  .footer-stats { gap: 32px; }

  .shelf-books { grid-template-columns: 1fr 1fr; }

  .section { padding: var(--space-lg) var(--space-sm); }

  .update-item { flex-wrap: wrap; }
}

@media (max-width: 480px) {
  .featured-books { grid-template-columns: 1fr; }
  .shelf-books { grid-template-columns: 1fr; }
  .hero h1 { font-size: 30px; }
  .hero-buttons { flex-direction: column; align-items: stretch; }
  .btn-primary, .btn-secondary { text-align: center; }
}