/* ============================================
   shared/theme.css — LessonWorkspace 全局主题
   学术出版风 · 温暖米白纸感 + 赤陶橙点缀
   Apple Design 启发：弹簧动效 · 毛玻璃 · 暗色模式
   ============================================ */

/* ─── 字体导入 ─── */
@import url('https://fonts.googleapis.com/css2?family=Noto+Serif+SC:wght@400;600;700;900&family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500&family=Newsreader:ital,wght@0,400;0,600;1,400&display=swap');

/* ─── Design Tokens ─── */
:root {
  /* 色板 */
  --paper:        #F7F4EE;
  --paper-light:  #FBFAF7;
  --ink:          #1A1A2E;
  --ink-80:       #3A3A4A;
  --ink-60:       #5A5A6A;
  --ink-40:       #8A8A9A;
  --ink-20:       #BABAC6;
  --accent:       #CC785C;
  --accent-light: #E8C4B0;
  --accent-deep:  #A85D42;
  --accent-dim:   rgba(204, 120, 92, 0.12);
  --border:       #E8E4DC;
  --border-light: #F0ECE4;
  --success:      #5A9E6F;
  --code-bg:      #F0EDE6;

  /* 字体栈 */
  --font-serif:   'Noto Serif SC', 'Newsreader', Georgia, 'Times New Roman', serif;
  --font-sans:    'Inter', -apple-system, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-mono:    'JetBrains Mono', 'SF Mono', 'Fira Code', monospace;
  --font-decorative: 'Newsreader', Georgia, serif;

  /* 字号系统 */
  --text-xs:   0.75rem;
  --text-sm:   0.875rem;
  --text-base: 1rem;
  --text-lg:   1.125rem;
  --text-xl:   1.25rem;
  --text-2xl:  1.5rem;
  --text-3xl:  1.875rem;
  --text-4xl:  2.25rem;
  --text-5xl:  3rem;
  --text-6xl:  3.75rem;

  /* 间距系统 */
  --space-1:  0.25rem;
  --space-2:  0.5rem;
  --space-3:  0.75rem;
  --space-4:  1rem;
  --space-5:  1.25rem;
  --space-6:  1.5rem;
  --space-7:  1.75rem;
  --space-8:  2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-14: 3.5rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;

  /* 圆角 */
  --radius-sm:  4px;
  --radius-md:  8px;
  --radius-lg:  12px;
  --radius-xl:  16px;

  /* 阴影 */
  --shadow-sm:  0 1px 2px rgba(26, 26, 46, 0.04);
  --shadow-md:  0 4px 12px rgba(26, 26, 46, 0.06);
  --shadow-lg:  0 8px 30px rgba(26, 26, 46, 0.08);
  --shadow-xl:  0 20px 60px rgba(26, 26, 46, 0.10);

  /* 阅读宽度 */
  --reading-width: 720px;
  --content-width: 1100px;
}

/* ─── Reset ─── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-sans);
  background: var(--paper);
  color: var(--ink);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ─── Typography ─── */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-serif);
  font-weight: 700;
  line-height: 1.3;
  color: var(--ink);
}
h1 { font-size: var(--text-4xl); margin-bottom: var(--space-6); }
h2 { font-size: var(--text-3xl); margin-bottom: var(--space-4); margin-top: var(--space-8); }
h3 { font-size: var(--text-2xl); margin-bottom: var(--space-3); margin-top: var(--space-6); }
h4 { font-size: var(--text-xl); margin-bottom: var(--space-2); margin-top: var(--space-4); }

p { margin-bottom: var(--space-4); }
a { color: var(--accent-deep); text-decoration: none; transition: color .15s; }
a:hover { color: var(--accent); text-decoration: underline; }

code, pre {
  font-family: var(--font-mono);
  font-size: .9em;
}
code {
  background: var(--code-bg);
  padding: .15em .4em;
  border-radius: var(--radius-sm);
}
pre {
  background: var(--code-bg);
  padding: var(--space-4);
  border-radius: var(--radius-md);
  overflow-x: auto;
  line-height: 1.5;
  margin-bottom: var(--space-4);
}

::selection {
  background: var(--accent-dim);
  color: var(--ink);
}

/* ─── Utility Classes ─── */
.reading-width { max-width: var(--reading-width); margin-left: auto; margin-right: auto; }
.content-width { max-width: var(--content-width); margin-left: auto; margin-right: auto; }

.tag {
  display: inline-block;
  padding: .15em .6em;
  border-radius: var(--radius-sm);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: .04em;
  text-transform: uppercase;
  font-family: var(--font-sans);
}
.tag-accent { background: var(--accent-dim); color: var(--accent-deep); }
.tag-green { background: rgba(90, 158, 111, 0.12); color: var(--success); }
.tag-blue { background: rgba(66, 133, 244, 0.12); color: #1a5fb4; }

/* ─── Cards ─── */
.card {
  background: var(--paper-light);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  transition: transform 0.35s cubic-bezier(0.34, 1.56, 0.64, 1),
              box-shadow 0.35s cubic-bezier(0.34, 1.56, 0.64, 1),
              border-color 0.25s ease;
}
.card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-3px);
  border-color: var(--accent-light);
}
.card:active {
  transform: translateY(-1px) scale(0.98);
}

/* ─── Buttons ─── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: .5rem 1.2rem;
  border-radius: var(--radius-md);
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: transform 0.2s cubic-bezier(0.34, 1.56, 0.64, 1),
              background 0.2s ease,
              border-color 0.2s ease;
  text-decoration: none;
  -webkit-tap-highlight-color: transparent;
}
.btn:active {
  transform: scale(0.95);
}
.btn-accent {
  background: var(--accent);
  color: white;
}
.btn-accent:hover {
  background: var(--accent-deep);
  color: white;
  text-decoration: none;
}
.btn-outline {
  background: transparent;
  color: var(--ink-60);
  border: 1px solid var(--border);
}
.btn-outline:hover {
  border-color: var(--accent);
  color: var(--accent-deep);
  text-decoration: none;
}

/* ─── Dividers ─── */
hr {
  border: none;
  height: 1px;
  background: var(--border);
  margin: var(--space-8) 0;
}

.section-divider {
  width: 60px;
  height: 3px;
  background: var(--accent);
  border-radius: 2px;
  margin: var(--space-4) 0 var(--space-6);
}

/* ─── Highlight / Blockquote ─── */
blockquote {
  border-left: 3px solid var(--accent);
  padding: var(--space-4) var(--space-6);
  margin: var(--space-6) 0;
  background: var(--accent-dim);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  font-family: var(--font-serif);
  font-style: italic;
  color: var(--ink-80);
}

.highlight-box {
  background: var(--accent-dim);
  border-left: 4px solid var(--accent);
  padding: var(--space-4) var(--space-6);
  margin: var(--space-4) 0;
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  font-size: .95rem;
}

/* ─── Tables ─── */
table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--space-4) 0;
  font-size: var(--text-sm);
}
th, td {
  border: 1px solid var(--border);
  padding: .5rem .75rem;
  text-align: left;
}
th {
  background: var(--paper);
  font-family: var(--font-serif);
  font-weight: 700;
  color: var(--ink-80);
}
tr:nth-child(even) { background: var(--paper-light); }

/* ─── Lists ─── */
ul, ol { margin-bottom: var(--space-4); padding-left: 1.5rem; }
li { margin-bottom: var(--space-2); }

/* ─── Header / Navbar ─── */
.site-header {
  background: var(--paper-light);
  border-bottom: 1px solid var(--border);
  padding: var(--space-4) var(--space-8);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
}
.site-header .inner {
  max-width: var(--content-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.site-header .logo {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: var(--text-lg);
  color: var(--ink);
  text-decoration: none;
}
.site-header .logo span { color: var(--accent); }
.site-header .logo:hover { text-decoration: none; color: var(--ink); }
.site-header nav a {
  margin-left: var(--space-6);
  font-size: var(--text-sm);
  color: var(--ink-60);
  font-weight: 500;
}
.site-header nav a:hover { color: var(--accent-deep); }

/* ─── Footer ─── */
.site-footer {
  border-top: 1px solid var(--border);
  padding: var(--space-8) var(--space-6);
  text-align: center;
  font-size: var(--text-sm);
  color: var(--ink-40);
  margin-top: var(--space-16);
}

/* ─── Grid ─── */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-6); }
.grid-3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: var(--space-6); }

/* ─── Responsive ─── */
@media (max-width: 768px) {
  .grid-2, .grid-3 { grid-template-columns: 1fr; }
  .site-header .inner { flex-direction: column; gap: var(--space-3); }
  .site-header nav a { margin: 0 var(--space-3); }
  h1 { font-size: var(--text-3xl); }
  h2 { font-size: var(--text-2xl); }
}

/* ─── Print ─── */
@media print {
  .site-header, .site-footer { display: none; }
  body { background: white; color: black; }
  .card { box-shadow: none; border: 1px solid #ccc; }
}

/* ════════════════════════════════════════════════════
   Apple Design 增强
   ════════════════════════════════════════════════════ */

/* ─── 1. 暗色模式 ─── */
@media (prefers-color-scheme: dark) {
  :root {
    --paper:        #1A1A2E;
    --paper-light:  #22223A;
    --ink:          #EDEDEE;
    --ink-80:       #C8C8D0;
    --ink-60:       #A0A0B0;
    --ink-40:       #707080;
    --ink-20:       #505060;
    --accent:       #E8A88C;
    --accent-light: #C88A72;
    --accent-deep:  #F0C8B8;
    --accent-dim:   rgba(232, 168, 140, 0.15);
    --border:       #3A3A4A;
    --border-light: #2A2A3A;
    --success:      #7AB893;
    --code-bg:      #2A2A3A;
    --shadow-sm:  0 1px 2px rgba(0, 0, 0, 0.2);
    --shadow-md:  0 4px 12px rgba(0, 0, 0, 0.3);
    --shadow-lg:  0 8px 30px rgba(0, 0, 0, 0.35);
    --shadow-xl:  0 20px 60px rgba(0, 0, 0, 0.40);
  }
  .site-header {
    background: rgba(34, 34, 58, 0.85);
  }
  .card, .group-shell, .collection-card, .collection-block,
  .stat, .hero-panel, .hero-feature-box {
    background: rgba(34, 34, 58, 0.6);
  }
  .hero-meta span, .group-meta span, .collection-meta span {
    background: rgba(34, 34, 58, 0.7);
    border-color: var(--border);
  }
  .workspace-topbar {
    background: rgba(232, 168, 140, 0.10);
    border-bottom-color: var(--border);
  }
  ::selection {
    background: rgba(232, 168, 140, 0.25);
    color: #EDEDEE;
  }
  blockquote {
    background: rgba(232, 168, 140, 0.08);
    border-left-color: var(--accent);
  }
  code {
    background: var(--code-bg);
    color: var(--ink-80);
  }
  pre {
    background: var(--code-bg);
  }
  .lesson-card {
    background: rgba(34, 34, 58, 0.6);
    border-color: var(--border);
  }
  .lesson-card:hover {
    background: rgba(34, 34, 58, 0.8);
  }
  .topic-card {
    background: rgba(34, 34, 58, 0.6);
  }
  .project-card {
    background: rgba(34, 34, 58, 0.6);
  }
  .btn-primary, .btn-accent {
    color: var(--paper);
  }
  .btn-primary:hover, .btn-accent:hover {
    color: var(--paper);
  }
  .tag-blue {
    color: #7AB893;
  }
  .project-card .btn-ghost {
    border-color: var(--border);
    color: var(--ink-60);
  }
  .ss-vocab-section,
  .ss-daily-goal,
  .ss-prefs,
  .ref-card {
    background: rgba(34, 34, 58, 0.5);
  }
  .achievement-card {
    background: rgba(34, 34, 58, 0.6);
  }
  img {
    opacity: 0.85;
    transition: opacity 0.3s ease;
  }
  img:hover {
    opacity: 1;
  }
}

/* ─── 2. Reduced motion（动效降级） ─── */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.05s !important;
    scroll-behavior: auto !important;
  }
  .card:hover,
  .lesson-card:hover,
  .project-card:hover,
  .topic-card:hover {
    transform: none !important;
  }
}

/* ─── 3. 入口动画 ─── */
@keyframes fade-up {
  from { opacity: 0; transform: translateY(20px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes fade-in {
  from { opacity: 0; }
  to   { opacity: 1; }
}
@keyframes scale-in {
  from { opacity: 0; transform: scale(0.93); }
  to   { opacity: 1; transform: scale(1); }
}
@keyframes slide-up {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* —— 单元素入口 —— */
.animate-in {
  animation: fade-up 0.5s cubic-bezier(0.22, 1, 0.36, 1) both;
}
.animate-in-fast {
  animation: fade-up 0.35s cubic-bezier(0.22, 1, 0.36, 1) both;
}

/* —— 交错入场（给网格容器用） —— */
.animate-stagger > * {
  animation: fade-up 0.5s cubic-bezier(0.22, 1, 0.36, 1) both;
}
.animate-stagger > *:nth-child(1)  { animation-delay: 0.0s; }
.animate-stagger > *:nth-child(2)  { animation-delay: 0.06s; }
.animate-stagger > *:nth-child(3)  { animation-delay: 0.12s; }
.animate-stagger > *:nth-child(4)  { animation-delay: 0.18s; }
.animate-stagger > *:nth-child(5)  { animation-delay: 0.24s; }
.animate-stagger > *:nth-child(6)  { animation-delay: 0.30s; }
.animate-stagger > *:nth-child(7)  { animation-delay: 0.36s; }
.animate-stagger > *:nth-child(8)  { animation-delay: 0.42s; }
.animate-stagger > *:nth-child(9)  { animation-delay: 0.48s; }
.animate-stagger > *:nth-child(10) { animation-delay: 0.54s; }
.animate-stagger > *:nth-child(11) { animation-delay: 0.60s; }
.animate-stagger > *:nth-child(12) { animation-delay: 0.66s; }

/* —— Hero 内容默认入场 —— */
.hero .inner {
  animation: fade-in 0.4s ease both;
}
.hero-copy .badge {
  animation: slide-up 0.4s cubic-bezier(0.22, 1, 0.36, 1) both;
  animation-delay: 0.1s;
}
.hero-copy h1 {
  animation: fade-up 0.5s cubic-bezier(0.22, 1, 0.36, 1) both;
  animation-delay: 0.15s;
}
.hero-copy .subtitle {
  animation: fade-up 0.5s cubic-bezier(0.22, 1, 0.36, 1) both;
  animation-delay: 0.2s;
}
.hero-meta {
  animation: fade-up 0.5s cubic-bezier(0.22, 1, 0.36, 1) both;
  animation-delay: 0.25s;
}
.hero-panel,
.hero-feature-box {
  animation: fade-up 0.5s cubic-bezier(0.22, 1, 0.36, 1) both;
  animation-delay: 0.3s;
}

/* ─── 4. 毛玻璃 · 浮层效果 ─── */
.glass {
  background: rgba(255, 255, 255, 0.55);
  backdrop-filter: blur(16px) saturate(160%);
  -webkit-backdrop-filter: blur(16px) saturate(160%);
  border: 1px solid rgba(255, 255, 255, 0.3);
}
.glass-heavy {
  background: rgba(255, 255, 255, 0.72);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border: 1px solid rgba(255, 255, 255, 0.4);
}
@media (prefers-color-scheme: dark) {
  .glass {
    background: rgba(34, 34, 58, 0.55);
    border-color: rgba(255, 255, 255, 0.08);
  }
  .glass-heavy {
    background: rgba(34, 34, 58, 0.72);
    border-color: rgba(255, 255, 255, 0.12);
  }
}

/* ─── 5. 弹簧 hover 工具类（避免全局冲突，按需使用） ─── */
.spring-hover {
  transition: transform 0.35s cubic-bezier(0.34, 1.56, 0.64, 1),
              box-shadow 0.35s cubic-bezier(0.34, 1.56, 0.64, 1),
              border-color 0.25s ease !important;
}
.spring-hover:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
}
.spring-hover:active {
  transform: translateY(-1px) scale(0.98);
}

/* ─── 6. Stagger 辅助（对内联 style 的 grid 也可以用） ─── */
@media (max-width: 768px) {
  .animate-stagger > * {
    animation-delay: 0s !important;
  }
  .hero-copy .badge,
  .hero-copy h1,
  .hero-copy .subtitle,
  .hero-meta,
  .hero-panel,
  .hero-feature-box {
    animation-delay: 0s !important;
  }
}