/* ============================================
   AI清源 — 全局样式
   ============================================ */

/* --- Reset & Base --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  -moz-text-size-adjust: none;
  -webkit-text-size-adjust: none;
  text-size-adjust: none;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  scroll-behavior: smooth;
  hanging-punctuation: first last;
}

/* --- Design Tokens --- */
:root {
  /* Type Scale */
  --text-xs:   clamp(0.75rem,  0.7rem  + 0.25vw, 0.875rem);
  --text-sm:   clamp(0.875rem, 0.8rem  + 0.35vw, 1rem);
  --text-base: clamp(1rem,     0.95rem + 0.25vw, 1.125rem);
  --text-lg:   clamp(1.125rem, 1rem    + 0.75vw, 1.5rem);
  --text-xl:   clamp(1.5rem,   1.2rem  + 1.25vw, 2.25rem);

  /* Spacing (4px base) */
  --space-1:  0.25rem;
  --space-2:  0.5rem;
  --space-3:  0.75rem;
  --space-4:  1rem;
  --space-5:  1.25rem;
  --space-6:  1.5rem;
  --space-8:  2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;

  /* Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.16, 1, 0.3, 1);
  --transition-base: 250ms cubic-bezier(0.16, 1, 0.3, 1);

  /* Content widths */
  --content-wide: 1200px;

  /* Font */
  --font-body: 'Inter', -apple-system, 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

/* --- Light Mode (default) --- */
:root, [data-theme="light"] {
  --color-bg: #F5F0E8;
  --color-surface: #FFFFFF;
  --color-surface-hover: #FAF8F5;
  --color-border: #E5E0D8;
  --color-border-light: #EDEAE5;
  --color-divider: #E8E4DD;

  --color-text: #2C2A25;
  --color-text-secondary: #6B6860;
  --color-text-muted: #9B9890;

  --color-primary: #1A7A7E;
  --color-primary-hover: #15686C;
  --color-primary-active: #10555A;
  --color-primary-light: #E6F3F3;

  --color-tag-bg: #F0EDE6;
  --color-tag-text: #5A5750;
  --color-tag-active-bg: #1A7A7E;
  --color-tag-active-text: #FFFFFF;

  --shadow-sm: 0 1px 3px rgba(60, 50, 30, 0.06);
  --shadow-md: 0 4px 12px rgba(60, 50, 30, 0.08);
  --shadow-lg: 0 8px 24px rgba(60, 50, 30, 0.1);
  --shadow-card: 0 1px 3px rgba(60, 50, 30, 0.05), 0 1px 2px rgba(60, 50, 30, 0.04);
  --shadow-card-hover: 0 8px 24px rgba(60, 50, 30, 0.1), 0 2px 6px rgba(60, 50, 30, 0.06);

  --color-toast-bg: #2C2A25;
  --color-toast-text: #F5F0E8;

  color-scheme: light;
}

/* --- Dark Mode --- */
[data-theme="dark"] {
  --color-bg: #1A1915;
  --color-surface: #242320;
  --color-surface-hover: #2A2926;
  --color-border: #3A3835;
  --color-border-light: #302E2B;
  --color-divider: #333130;

  --color-text: #E0DED8;
  --color-text-secondary: #A8A6A0;
  --color-text-muted: #706E68;

  --color-primary: #4FABB0;
  --color-primary-hover: #3D969B;
  --color-primary-active: #2B8186;
  --color-primary-light: #1E2E2F;

  --color-tag-bg: #2A2926;
  --color-tag-text: #A8A6A0;
  --color-tag-active-bg: #4FABB0;
  --color-tag-active-text: #1A1915;

  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.35);
  --shadow-card: 0 1px 3px rgba(0, 0, 0, 0.15), 0 1px 2px rgba(0, 0, 0, 0.1);
  --shadow-card-hover: 0 8px 24px rgba(0, 0, 0, 0.3), 0 2px 6px rgba(0, 0, 0, 0.2);

  --color-toast-bg: #E0DED8;
  --color-toast-text: #1A1915;

  color-scheme: dark;
}

/* --- Body --- */
body {
  min-height: 100dvh;
  line-height: 1.6;
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-text);
  background-color: var(--color-bg);
  transition: background-color var(--transition-base), color var(--transition-base);
}

/* --- Interactive Transitions --- */
a, button, [role="button"], input, textarea, select {
  transition: color var(--transition-fast),
              background var(--transition-fast),
              border-color var(--transition-fast),
              box-shadow var(--transition-fast),
              transform var(--transition-fast);
}

button { cursor: pointer; background: none; border: none; font: inherit; color: inherit; }
a { text-decoration: none; color: inherit; }

img, svg { display: block; max-width: 100%; }

:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

::selection {
  background: rgba(26, 122, 126, 0.2);
  color: var(--color-text);
}

/* --- Screen Reader Only --- */
.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border-width: 0;
}

/* ============================================
   Header / Navigation
   ============================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border-light);
  box-shadow: var(--shadow-sm);
  transition: background var(--transition-base), border-color var(--transition-base);
}

.header-inner {
  max-width: var(--content-wide);
  margin: 0 auto;
  padding: var(--space-3) var(--space-6);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
}

.logo svg {
  width: 32px;
  height: 32px;
}

.logo-text {
  font-size: var(--text-lg);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--color-text);
}

.main-nav {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.nav-link {
  padding: var(--space-2) var(--space-4);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  border-radius: var(--radius-md);
  white-space: nowrap;
}

.nav-link:hover {
  color: var(--color-text);
  background: var(--color-tag-bg);
}

.nav-link.active {
  color: var(--color-primary);
  background: var(--color-primary-light);
  font-weight: 600;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
}

.theme-toggle {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  color: var(--color-text-secondary);
}

.theme-toggle:hover {
  background: var(--color-tag-bg);
  color: var(--color-text);
}

.theme-toggle svg {
  width: 20px;
  height: 20px;
}

/* Mobile menu button */
.mobile-menu-btn {
  display: none;
  width: 36px;
  height: 36px;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  color: var(--color-text-secondary);
}

.mobile-menu-btn:hover {
  background: var(--color-tag-bg);
  color: var(--color-text);
}

.mobile-menu-btn svg {
  width: 22px;
  height: 22px;
}

/* ============================================
   Main Content
   ============================================ */
.main-content {
  max-width: var(--content-wide);
  margin: 0 auto;
  padding: var(--space-8) var(--space-6);
  min-height: calc(100dvh - 200px);
}

/* --- Page Title Section --- */
.page-header {
  margin-bottom: var(--space-8);
}

.page-title {
  font-size: var(--text-xl);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-2);
  color: var(--color-text);
}

.page-description {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  max-width: 60ch;
}

/* --- Search --- */
.search-section {
  margin-bottom: var(--space-6);
}

.search-box {
  position: relative;
  max-width: 480px;
}

.search-icon {
  position: absolute;
  left: var(--space-4);
  top: 50%;
  transform: translateY(-50%);
  color: var(--color-text-muted);
  pointer-events: none;
  width: 18px;
  height: 18px;
}

.search-input {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  padding-left: calc(var(--space-4) + 18px + var(--space-2));
  padding-right: calc(var(--space-4) + 28px);
  font-size: var(--text-sm);
  color: var(--color-text);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  outline: none;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.search-input::placeholder {
  color: var(--color-text-muted);
}

.search-input:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(26, 122, 126, 0.12);
}

.search-input::-webkit-search-cancel-button {
  -webkit-appearance: none;
  display: none;
}

.search-clear {
  position: absolute;
  right: var(--space-3);
  top: 50%;
  transform: translateY(-50%);
  width: 24px;
  height: 24px;
  display: none;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-full);
  color: var(--color-text-muted);
  font-size: 14px;
  line-height: 1;
}

.search-clear:hover {
  background: var(--color-tag-bg);
  color: var(--color-text);
}

.search-clear.visible {
  display: flex;
}

/* --- Category Filter --- */
.filter-section {
  margin-bottom: var(--space-6);
}

.filter-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.filter-tag {
  padding: var(--space-1) var(--space-4);
  font-size: var(--text-xs);
  font-weight: 500;
  color: var(--color-tag-text);
  background: var(--color-tag-bg);
  border-radius: var(--radius-full);
  white-space: nowrap;
  line-height: 1.6;
}

.filter-tag:hover {
  background: var(--color-border);
  color: var(--color-text);
}

.filter-tag.active {
  background: var(--color-tag-active-bg);
  color: var(--color-tag-active-text);
}

/* --- Card Grid --- */
.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-5);
  margin-bottom: var(--space-8);
}

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-card);
  transition: box-shadow var(--transition-base), transform var(--transition-base), border-color var(--transition-fast);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.card:hover {
  box-shadow: var(--shadow-card-hover);
  transform: translateY(-2px);
  border-color: var(--color-border);
}

.card-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
}

.card-category {
  display: inline-flex;
  padding: var(--space-1) var(--space-3);
  font-size: var(--text-xs);
  font-weight: 500;
  color: var(--color-primary);
  background: var(--color-primary-light);
  border-radius: var(--radius-full);
  white-space: nowrap;
  line-height: 1.4;
}

.card-date {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  flex-shrink: 0;
}

.card-title {
  font-size: var(--text-base);
  font-weight: 600;
  color: var(--color-text);
  line-height: 1.4;
  letter-spacing: -0.01em;
}

.card-description {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: 1.6;
  flex: 1;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  margin-top: auto;
  padding-top: var(--space-3);
  border-top: 1px solid var(--color-border-light);
}

.card-meta {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.card-meta svg {
  width: 14px;
  height: 14px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  font-size: var(--text-xs);
  font-weight: 500;
  border-radius: var(--radius-md);
  white-space: nowrap;
  line-height: 1.4;
}

.btn-primary {
  background: var(--color-primary);
  color: #FFFFFF;
}

.btn-primary:hover {
  background: var(--color-primary-hover);
}

.btn-primary:active {
  background: var(--color-primary-active);
}

.btn-outline {
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
  background: transparent;
}

.btn-outline:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: var(--color-primary-light);
}

.btn svg {
  width: 14px;
  height: 14px;
}

/* --- Pagination --- */
.pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-4) 0;
}

.pagination-info {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-right: var(--space-4);
}

.page-btn {
  min-width: 36px;
  height: 36px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0 var(--space-2);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
}

.page-btn:hover:not(:disabled) {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: var(--color-primary-light);
}

.page-btn.active {
  background: var(--color-primary);
  color: #FFFFFF;
  border-color: var(--color-primary);
}

.page-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.page-btn svg {
  width: 16px;
  height: 16px;
}

/* --- Empty State --- */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: var(--space-16) var(--space-8);
  color: var(--color-text-muted);
}

.empty-state-icon {
  width: 56px;
  height: 56px;
  margin-bottom: var(--space-4);
  color: var(--color-text-muted);
  opacity: 0.5;
}

.empty-state-icon svg {
  width: 100%;
  height: 100%;
}

.empty-state h3 {
  font-size: var(--text-lg);
  font-weight: 600;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-2);
}

.empty-state p {
  font-size: var(--text-sm);
  max-width: 36ch;
}

/* ============================================
   Detail Page
   ============================================ */
.detail-header {
  margin-bottom: var(--space-8);
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-6);
  padding: var(--space-2) 0;
}

.back-link:hover {
  color: var(--color-primary);
}

.back-link svg {
  width: 16px;
  height: 16px;
}

.detail-meta {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
  flex-wrap: wrap;
}

.detail-title {
  font-size: var(--text-xl);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--color-text);
  margin-bottom: var(--space-3);
}

.detail-date {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

/* Content area */
.detail-content {
  background: var(--color-surface);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
  box-shadow: var(--shadow-sm);
}

.content-actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-6);
  padding-bottom: var(--space-4);
  border-bottom: 1px solid var(--color-border-light);
}

.btn-copy, .btn-download {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-5);
  font-size: var(--text-sm);
  font-weight: 500;
  border-radius: var(--radius-md);
}

.btn-copy {
  background: var(--color-primary);
  color: #FFFFFF;
}

.btn-copy:hover {
  background: var(--color-primary-hover);
}

.btn-download {
  background: var(--color-primary);
  color: #FFFFFF;
}

.btn-download:hover {
  background: var(--color-primary-hover);
}

.btn-copy svg, .btn-download svg {
  width: 16px;
  height: 16px;
}

.content-body {
  font-size: var(--text-sm);
  line-height: 1.8;
  color: var(--color-text);
}

.content-body pre {
  background: var(--color-bg);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
  padding: var(--space-4);
  overflow-x: auto;
  font-family: 'JetBrains Mono', 'Fira Code', 'SF Mono', Consolas, monospace;
  font-size: var(--text-xs);
  line-height: 1.7;
  margin: var(--space-4) 0;
}

.content-body code {
  font-family: 'JetBrains Mono', 'Fira Code', 'SF Mono', Consolas, monospace;
  font-size: 0.9em;
  background: var(--color-tag-bg);
  padding: 0.15em 0.4em;
  border-radius: var(--radius-sm);
}

.content-body pre code {
  background: none;
  padding: 0;
  border-radius: 0;
}

.content-body h1, .content-body h2, .content-body h3, .content-body h4 {
  margin-top: var(--space-6);
  margin-bottom: var(--space-3);
  font-weight: 600;
  color: var(--color-text);
}

.content-body h1 { font-size: var(--text-lg); }
.content-body h2 { font-size: calc(var(--text-base) * 1.1); }
.content-body h3 { font-size: var(--text-base); }

.content-body p {
  margin-bottom: var(--space-3);
}

.content-body ul, .content-body ol {
  margin: var(--space-3) 0;
  padding-left: var(--space-6);
}

.content-body li {
  margin-bottom: var(--space-1);
}

.content-body table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--space-4) 0;
  font-size: var(--text-xs);
}

.content-body th, .content-body td {
  padding: var(--space-2) var(--space-3);
  border: 1px solid var(--color-border-light);
  text-align: left;
}

.content-body th {
  background: var(--color-tag-bg);
  font-weight: 600;
}

.content-body strong {
  font-weight: 600;
  color: var(--color-text);
}

.content-body hr {
  border: none;
  border-top: 1px solid var(--color-border-light);
  margin: var(--space-6) 0;
}

/* Resource detail specifics */
.resource-info {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  margin-bottom: var(--space-4);
  padding: var(--space-4);
  background: var(--color-primary-light);
  border-radius: var(--radius-md);
}

.resource-info-item {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
}

.resource-info-item svg {
  width: 16px;
  height: 16px;
  color: var(--color-primary);
}

/* ============================================
   Toast
   ============================================ */
.toast {
  position: fixed;
  bottom: var(--space-8);
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  padding: var(--space-3) var(--space-6);
  background: var(--color-toast-bg);
  color: var(--color-toast-text);
  font-size: var(--text-sm);
  font-weight: 500;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease, transform 0.3s ease;
  z-index: 1000;
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ============================================
   Footer
   ============================================ */
.site-footer {
  border-top: 1px solid var(--color-border-light);
  padding: var(--space-8) var(--space-6);
  text-align: center;
  transition: border-color var(--transition-base);
}

.footer-inner {
  max-width: var(--content-wide);
  margin: 0 auto;
}

.footer-text {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

.footer-text a {
  color: var(--color-primary);
}

.footer-text a:hover {
  text-decoration: underline;
}

.footer-icp {
  margin-top: var(--space-2);
}

/* ============================================
   Responsive Design
   ============================================ */

/* Tablet */
@media (max-width: 900px) {
  .card-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .main-content {
    padding: var(--space-6) var(--space-4);
  }
}

/* Mobile */
@media (max-width: 640px) {
  .header-inner {
    padding: var(--space-3) var(--space-4);
  }

  .main-nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border-light);
    box-shadow: var(--shadow-md);
    flex-direction: column;
    padding: var(--space-2) var(--space-4);
    gap: 0;
  }

  .main-nav.open {
    display: flex;
  }

  .nav-link {
    padding: var(--space-3) var(--space-4);
    width: 100%;
    text-align: left;
    border-radius: var(--radius-md);
  }

  .mobile-menu-btn {
    display: flex;
  }

  .card-grid {
    grid-template-columns: 1fr;
    gap: var(--space-4);
  }

  .main-content {
    padding: var(--space-5) var(--space-4);
  }

  .page-title {
    font-size: var(--text-lg);
  }

  .search-box {
    max-width: 100%;
  }

  .filter-tags {
    flex-wrap: nowrap;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    padding-bottom: var(--space-1);
  }

  .filter-tags::-webkit-scrollbar {
    display: none;
  }

  .pagination {
    flex-wrap: wrap;
    gap: var(--space-1);
  }

  .pagination-info {
    width: 100%;
    text-align: center;
    margin-right: 0;
    margin-bottom: var(--space-2);
  }

  .detail-content {
    padding: var(--space-5);
  }

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

  .detail-title {
    font-size: var(--text-lg);
  }

  .resource-info {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-3);
  }
}

/* ============================================
   Skeleton Loading
   ============================================ */
.skeleton-card {
  pointer-events: none;
}

.skeleton-line {
  height: 14px;
  border-radius: 4px;
  background: var(--border);
  margin-bottom: var(--space-3);
  animation: skeleton-pulse 1.5s ease-in-out infinite;
}

.skeleton-short { width: 30%; }
.skeleton-title { width: 70%; height: 20px; margin-bottom: var(--space-4); }
.skeleton-full { width: 100%; }
.skeleton-medium { width: 60%; }

@keyframes skeleton-pulse {
  0%, 100% { opacity: 0.4; }
  50% { opacity: 0.8; }
}

/* ============================================
   Reduced Motion
   ============================================ */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}