/* ============================================================
   Design Tokens
   ============================================================ */
:root {
  --color-primary:        #3B6FF7;
  --color-primary-light:  #EBF0FF;
  --color-bg:             #F0F2F7;
  --color-surface:        #FFFFFF;
  --color-text:           #111827;
  --color-text-secondary: #6B7280;
  --color-border:         #E8EAF0;
  --color-sidebar-bg:     #FFFFFF;
  --color-sidebar-hover:  #F5F7FF;
  --color-sidebar-active: #EBF0FF;
  --color-sidebar-text:   #374151;

  --sidebar-w: 200px;
  --sidebar-collapsed-w: 52px;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --shadow-card: 0 1px 3px rgba(0,0,0,.06), 0 1px 2px rgba(0,0,0,.04);
  --shadow-card-hover: 0 4px 16px rgba(59,111,247,.10);
  --shadow-float: 0 2px 10px rgba(0,0,0,.10);

  --ease: cubic-bezier(0.4, 0, 0.2, 1);
  --dur: 0.18s;
  --font: "Inter","Noto Sans SC",system-ui,-apple-system,sans-serif;
}

[data-theme="dark"] {
  --color-bg:             #101218;
  --color-surface:        #1A1C26;
  --color-text:           #E5E7EB;
  --color-text-secondary: #9CA3AF;
  --color-border:         #272935;
  --color-sidebar-bg:     #1A1C26;
  --color-sidebar-hover:  #22243A;
  --color-sidebar-active: #21274A;
  --color-sidebar-text:   #D1D5DB;
  --shadow-card: 0 1px 3px rgba(0,0,0,.3);
  --shadow-card-hover: 0 4px 16px rgba(59,111,247,.18);
}

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

html {
  font-family: var(--font);
  font-size: 14px;
  color: var(--color-text);
  background: var(--color-bg);
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
}

body {
  min-height: 100dvh;
  display: flex;
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease);
}

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

/* ============================================================
   Sidebar
   ============================================================ */
.sidebar {
  width: var(--sidebar-w);
  flex-shrink: 0;
  position: sticky;
  top: 0;
  height: 100dvh;
  overflow-y: auto;
  overflow-x: hidden;
  background: var(--color-sidebar-bg);
  border-right: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease);
  z-index: 200;
  scrollbar-width: none;
}
.sidebar::-webkit-scrollbar { display: none; }

.sidebar-logo {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  padding: 14px 12px;
  border-bottom: 1px solid var(--color-border);
  flex-shrink: 0;
}

/* 收起按钮 - 居中展示 */
.sidebar-collapse-btn {
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-secondary);
  border-radius: var(--radius-sm);
  transition: background var(--dur) var(--ease), transform var(--dur) var(--ease);
  flex-shrink: 0;
}
.sidebar-collapse-btn:hover { background: var(--color-sidebar-hover); color: var(--color-text); }
.sidebar-collapse-btn svg { width: 14px; height: 14px; }

/* 折叠态 */
.sidebar.collapsed {
  width: var(--sidebar-collapsed-w);
}
.sidebar.collapsed .sidebar-collapse-btn {
  transform: rotate(180deg);
}
.sidebar.collapsed .sidebar-item {
  border-left-color: transparent !important;
}
.sidebar.collapsed .sidebar-item.active {
  border-left-color: transparent !important;
}

.sidebar-nav {
  flex: 1;
  padding: 12px 8px;
  overflow-y: auto;
  scrollbar-width: none;
}
.sidebar-nav::-webkit-scrollbar { display: none; }

/* 分组标签 */
.sidebar-section-label {
  padding: 12px 12px 4px;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
  opacity: 0.6;
  user-select: none;
}
.sidebar-section-label:first-child { padding-top: 4px; }

.sidebar-item {
  display: flex;
  align-items: center;
  gap: 10px;
  /* 8+2+6=16px → 20px icon 右辶=36px → 在 52px 折叠态中居中 (center=26px) */
  padding: 8px 8px 8px 6px;
  font-size: 1.025rem;
  font-weight: 500;
  color: var(--color-sidebar-text);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease), border-color var(--dur) var(--ease);
  white-space: nowrap;
  overflow: hidden;
  user-select: none;
  margin-bottom: 2px;
  border-left: 2px solid transparent;
}
.sidebar-item:hover {
  background: var(--color-sidebar-hover);
  color: var(--color-text);
}
.sidebar-item.active {
  background: var(--color-sidebar-active);
  color: var(--color-primary);
  font-weight: 600;
  border-left-color: var(--color-primary);
}

/* 分类图标 - 单色 */
.sidebar-item-icon {
  width: 20px;
  height: 20px;
  border-radius: 4px;
  object-fit: contain;
  flex-shrink: 0;
  opacity: 0.65;
  filter: brightness(0);
}
[data-theme="dark"] .sidebar-item-icon {
  filter: brightness(0) invert(1);
  opacity: 0.7;
}

.sidebar-item-letter {
  width: 20px;
  height: 20px;
  border-radius: 4px;
  background: var(--color-primary-light);
  color: var(--color-primary);
  font-size: 0.7rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  line-height: 1;
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease);
}
.sidebar-item.active .sidebar-item-letter {
  background: var(--color-primary);
  color: #fff;
}
.sidebar-item-name {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  flex: 1;
}

/* ============================================================
   Page Main
   ============================================================ */
.page-main {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
}

/* ============================================================
   Mobile Topbar
   ============================================================ */
.mobile-topbar {
  display: none;
  align-items: center;
  gap: 10px;
  padding: 12px 16px;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 150;
}

.hamburger {
  display: flex;
  flex-direction: column;
  gap: 5px;
  padding: 4px;
}
.hamburger span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
}

.mobile-title {
  font-weight: 700;
  font-size: 1rem;
  color: var(--color-primary);
}

/* ============================================================
   Search Section
   ============================================================ */
.search-section {
  padding: 32px 48px 20px;
  display: flex;
  justify-content: center;
  position: relative;
  z-index: 10;
}

.search-bar {
  display: flex;
  align-items: center;
  width: 100%;
  max-width: 640px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: visible;
  box-shadow: var(--shadow-card);
  transition: box-shadow var(--dur) var(--ease), border-color var(--dur) var(--ease);
  position: relative;
}
.search-bar:focus-within {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(59,111,247,.10), var(--shadow-card);
}

/* 搜索引擎 */
.engine-picker { position: relative; flex-shrink: 0; }

.engine-current {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 0 14px;
  height: 46px;
  font-size: 0.857rem;
  font-weight: 500;
  color: var(--color-text);
  white-space: nowrap;
  border-radius: var(--radius-lg) 0 0 var(--radius-lg);
  transition: background var(--dur) var(--ease);
}
.engine-current:hover { background: var(--color-bg); }
.engine-current svg { width: 13px; height: 13px; color: var(--color-text-secondary); }

.engine-dropdown {
  display: none;
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  min-width: 100px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: 0 8px 24px rgba(0,0,0,.10);
  z-index: 300;
  overflow: hidden;
}
.engine-dropdown.open { display: block; }

.engine-option {
  padding: 9px 16px;
  font-size: 0.857rem;
  color: var(--color-text);
  cursor: pointer;
  transition: background var(--dur) var(--ease);
}
.engine-option:hover { background: var(--color-bg); }
.engine-option.active { color: var(--color-primary); font-weight: 600; }

.search-divider {
  width: 1px;
  height: 18px;
  background: var(--color-border);
  flex-shrink: 0;
}

.search-input {
  flex: 1;
  min-width: 0;
  height: 46px;
  padding: 0 14px;
  border: none;
  outline: none;
  background: transparent;
  font-family: var(--font);
  font-size: 0.929rem;
  color: var(--color-text);
}
.search-input::placeholder { color: var(--color-text-secondary); }
.search-input::-webkit-search-cancel-button { display: none; }

.search-go {
  flex-shrink: 0;
  width: 46px;
  height: 46px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-secondary);
  border-radius: 0 var(--radius-lg) var(--radius-lg) 0;
  transition: color var(--dur) var(--ease), background var(--dur) var(--ease);
}
.search-go:hover { color: var(--color-primary); background: var(--color-bg); }
.search-go svg { width: 17px; height: 17px; }

/* ============================================================
   Content Area
   ============================================================ */
.content-area {
  flex: 1;
  padding: 0 48px 48px;
  min-width: 0;
}

/* ============================================================
   Page Mode（分页滑动）
   ============================================================ */
/* 给 body 固定高度，使 content-area 能获得正确的受约束高度 */
body.page-mode-active {
  height: 100dvh;
  overflow: hidden;
}
body.page-mode-active .site-footer {
  display: none;
}

.content-area.page-mode {
  padding: 0;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.page-track-wrap {
  flex: 1;
  overflow: hidden;
  position: relative;
  user-select: none;
}

.page-track {
  display: flex;
  height: 100%;
  transition: transform 0.42s cubic-bezier(0.4, 0, 0.2, 1);
  will-change: transform;
}

.page-slide {
  flex-shrink: 0;
  height: 100%;
  overflow-y: auto;
  overflow-x: hidden;
  padding: 0 48px 24px;
  scrollbar-width: thin;
  scrollbar-color: var(--color-border) transparent;
}
.page-slide::-webkit-scrollbar { width: 4px; }
.page-slide::-webkit-scrollbar-track { background: transparent; }
.page-slide::-webkit-scrollbar-thumb { background: var(--color-border); border-radius: 2px; }

/* Dots 指示器 */
.page-dots {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 8px 0 14px;
  flex-shrink: 0;
}
.page-dot {
  height: 6px;
  width: 6px;
  border-radius: 3px;
  background: var(--color-border);
  border: none;
  cursor: pointer;
  padding: 0;
  transition: width 0.28s var(--ease), background 0.28s var(--ease);
}
.page-dot:hover { background: var(--color-text-secondary); }
.page-dot.active {
  width: 20px;
  background: var(--color-primary);
}

/* ============================================================
   Link Group
   ============================================================ */
.link-group {
  margin-bottom: 36px;
  scroll-margin-top: 80px;
}

.group-header {
  display: flex;
  align-items: center;
  gap: 8px;
  padding-bottom: 12px;
  margin-bottom: 14px;
  border-bottom: 1px solid var(--color-border);
}

.group-title {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--color-text-secondary);
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

.group-count {
  font-size: 0.75rem;
  color: var(--color-text-secondary);
  background: var(--color-bg);
  padding: 1px 7px;
  border-radius: 20px;
  border: 1px solid var(--color-border);
}

/* ============================================================
   Cards Grid
   ============================================================ */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(230px, 1fr));
  gap: 8px;
}

/* ============================================================
   Link Card
   ============================================================ */
.link-card {
  display: flex;
  align-items: center;
  gap: 11px;
  padding: 11px 14px;
  background: var(--color-surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
  cursor: pointer;
  transition: box-shadow var(--dur) var(--ease), transform var(--dur) var(--ease);
  min-width: 0;
  overflow: hidden;
}
.link-card:hover {
  box-shadow: var(--shadow-card-hover);
  transform: translateY(-1px);
}

.card-icon-wrap {
  flex-shrink: 0;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.card-icon {
  width: 22px;
  height: 22px;
  object-fit: contain;
}

.card-icon-text {
  font-size: 0.857rem;
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1;
  text-transform: uppercase;
}

.card-body {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.card-title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  line-height: 1.45;
}

.card-desc {
  font-size: 0.72rem;
  color: var(--color-text-secondary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  line-height: 1.45;
}

/* ============================================================
   States
   ============================================================ */
.hidden { display: none !important; }

.loading-state {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 80px 0;
  color: var(--color-text-secondary);
  font-size: 0.929rem;
  justify-content: center;
}

.loading-spinner {
  width: 20px;
  height: 20px;
  border: 2px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

.empty-hint {
  padding: 24px 0;
  text-align: center;
  color: var(--color-text-secondary);
  font-size: 0.929rem;
}

/* ============================================================
   Floating Tools
   ============================================================ */
.floating-tools {
  position: fixed;
  right: 18px;
  bottom: 24px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  z-index: 500;
}

.float-btn {
  width: 34px;
  height: 34px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text-secondary);
  box-shadow: var(--shadow-float);
  transition: color var(--dur) var(--ease),
              border-color var(--dur) var(--ease),
              box-shadow var(--dur) var(--ease);
  cursor: pointer;
}
.float-btn:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
  box-shadow: 0 2px 10px rgba(59,111,247,.15);
}
.float-btn svg { width: 15px; height: 15px; }

[data-theme="light"] .icon-sun  { display: none; }
[data-theme="dark"]  .icon-moon { display: none; }

/* 链接打开方式切换 */
[data-linktarget="blank"] .icon-tab-self { display: none; }
[data-linktarget="self"]  .icon-tab-new  { display: none; }
[data-linktarget="self"]  #linkTargetBtn {
  color: var(--color-primary);
  border-color: var(--color-primary);
}

#backTop { opacity: 0; pointer-events: none; transition: opacity var(--dur) var(--ease); }
#backTop.visible { opacity: 1; pointer-events: auto; }

/* ============================================================
   Footer
   ============================================================ */
.site-footer {
  padding: 18px 48px;
  text-align: center;
  color: var(--color-text-secondary);
  font-size: 0.786rem;
  border-top: 1px solid var(--color-border);
}
.footer-link { color: var(--color-primary); }
.footer-link:hover { text-decoration: underline; }

/* ============================================================
   Overlay (mobile)
   ============================================================ */
.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.4);
  z-index: 190;
}

/* ============================================================
   Responsive
   ============================================================ */
@media (max-width: 768px) {
  body { flex-direction: column; }

  .sidebar {
    position: fixed;
    top: 0;
    left: 0;
    height: 100dvh;
    transform: translateX(-100%);
    transition: transform 0.25s var(--ease);
  }
  .sidebar.open { transform: translateX(0); }
  .sidebar-overlay.open { display: block; }
  .sidebar-collapse-btn { display: none; }
  .page-main { width: 100%; }
  .mobile-topbar { display: flex; }
  .search-section { padding: 16px 16px 12px; }
  .content-area { padding: 0 16px 32px; }
  .page-slide { padding: 0 16px 24px; }
  .floating-tools { right: 10px; }
  .site-footer { padding: 16px; }
}

@media (max-width: 480px) {
  .cards-grid { grid-template-columns: 1fr 1fr; }
}