/**
 * 组件：按钮、卡片、标签、搜索、空状态等
 */

/* ========== 按钮 ========== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  min-height: var(--tap-min);
  padding: 0.6rem 1.2rem;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1;
  text-decoration: none;
  transition:
    background var(--duration-fast) var(--ease-out),
    color var(--duration-fast) var(--ease-out),
    border-color var(--duration-fast) var(--ease-out),
    box-shadow var(--duration-fast) var(--ease-out),
    transform var(--duration-fast) var(--ease-out);
  white-space: nowrap;
  -webkit-tap-highlight-color: transparent;
}

.btn:active {
  transform: translateY(1px);
}

.btn--primary {
  background: var(--color-primary);
  color: #fff;
  box-shadow: 0 1px 2px rgba(47, 107, 79, 0.18);
}

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

.btn--secondary {
  background: var(--color-surface);
  color: var(--color-text);
  border-color: var(--color-border);
  box-shadow: var(--shadow-sm);
}

.btn--secondary:hover {
  border-color: var(--color-border-strong);
  color: var(--color-primary);
  background: var(--color-surface-elevated);
}

.btn--ghost {
  background: transparent;
  color: var(--color-text-muted);
}

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

.btn--icon {
  width: var(--tap-min);
  min-height: var(--tap-min);
  padding: 0;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-text-muted);
}

.btn--icon:hover {
  color: var(--color-primary);
  border-color: var(--color-border-strong);
}

.btn__icon {
  width: 1.15rem;
  height: 1.15rem;
  flex-shrink: 0;
}

/* ========== 徽章 ========== */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.3em;
  padding: 0.22em 0.6em;
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  font-weight: 600;
  line-height: 1.3;
  letter-spacing: 0.02em;
  white-space: nowrap;
}

.badge--demo {
  background: var(--color-demo-bg);
  color: var(--color-demo);
}

.badge--category {
  background: var(--color-primary-soft);
  color: var(--color-primary);
}

.badge--soft {
  background: var(--color-bg);
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
}

/* ========== 标签芯片 ========== */
.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  list-style: none;
  margin: 0;
  padding: 0;
}

.tag {
  display: inline-flex;
  align-items: center;
  min-height: 1.85rem;
  padding: 0.3em 0.75em;
  border-radius: var(--radius-full);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
  font-size: var(--text-xs);
  font-weight: 500;
  text-decoration: none;
  transition:
    border-color var(--duration-fast) var(--ease-out),
    color var(--duration-fast) var(--ease-out),
    background var(--duration-fast) var(--ease-out);
  -webkit-tap-highlight-color: transparent;
}

.tag:hover,
.tag.is-active {
  border-color: color-mix(in srgb, var(--color-primary) 40%, var(--color-border));
  color: var(--color-primary);
  background: var(--color-primary-soft);
}

/* 标签云尺寸 */
.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  align-items: center;
}

.tag-cloud .tag {
  font-size: var(--text-sm);
  min-height: 2.25rem;
  padding: 0.45em 0.95em;
}

.tag-cloud .tag--lg {
  font-size: var(--text-base);
}

.tag-cloud .tag--sm {
  font-size: var(--text-xs);
}

/* ========== 文章卡片 ========== */
.article-card {
  display: flex;
  flex-direction: column;
  height: 100%;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition:
    transform var(--duration) var(--ease-out),
    box-shadow var(--duration) var(--ease-out),
    border-color var(--duration) var(--ease-out);
}

@media (hover: hover) and (pointer: fine) {
  .article-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    border-color: color-mix(in srgb, var(--color-primary) 22%, var(--color-border));
  }

  .article-card:hover .article-card__cover img {
    transform: scale(1.025);
  }
}

.article-card__cover {
  position: relative;
  aspect-ratio: 16 / 10;
  overflow: hidden;
  background: var(--color-hero-from);
}

.article-card__cover img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--duration-slow) var(--ease-out);
}

.article-card__badges {
  position: absolute;
  top: var(--space-3);
  left: var(--space-3);
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.article-card__body {
  display: flex;
  flex-direction: column;
  flex: 1;
  padding: var(--space-5);
  gap: var(--space-3);
}

.article-card__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2) var(--space-3);
  color: var(--color-text-faint);
  font-size: var(--text-xs);
}

.article-card__title {
  margin: 0;
  font-size: var(--text-lg);
  line-height: var(--leading-snug);
  letter-spacing: -0.015em;
}

.article-card__title a {
  color: var(--color-text);
  text-decoration: none;
}

.article-card__title a:hover {
  color: var(--color-primary);
}

.article-card__summary {
  margin: 0;
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  line-height: var(--leading-relaxed);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
  flex: 1;
}

.article-card__footer {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  margin-top: auto;
  padding-top: var(--space-2);
}

/* ========== 分类卡片 ========== */
.category-card {
  display: block;
  padding: var(--space-6);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  text-decoration: none;
  color: inherit;
  box-shadow: var(--shadow-sm);
  transition:
    transform var(--duration) var(--ease-out),
    border-color var(--duration) var(--ease-out),
    box-shadow var(--duration) var(--ease-out);
  -webkit-tap-highlight-color: transparent;
}

@media (hover: hover) and (pointer: fine) {
  .category-card:hover {
    transform: translateY(-2px);
    border-color: color-mix(in srgb, var(--color-primary) 28%, var(--color-border));
    box-shadow: var(--shadow-md);
    color: inherit;
  }
}

.category-card:active {
  transform: scale(0.995);
}

.category-card__name {
  margin: 0 0 var(--space-2);
  font-size: var(--text-xl);
  color: var(--color-text);
  letter-spacing: -0.02em;
}

.category-card__desc {
  margin: 0 0 var(--space-4);
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  line-height: var(--leading-relaxed);
}

.category-card__count {
  color: var(--color-primary);
  font-size: var(--text-sm);
  font-weight: 600;
}

/* ========== 面包屑 ========== */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2);
  list-style: none;
  margin: 0 0 var(--space-6);
  padding: 0;
  font-size: var(--text-sm);
  color: var(--color-text-faint);
}

.breadcrumb > li {
  margin: 0;
}

.breadcrumb a {
  color: var(--color-text-muted);
  text-decoration: none;
}

.breadcrumb a:hover {
  color: var(--color-primary);
}

.breadcrumb__sep {
  opacity: 0.45;
  user-select: none;
}

.breadcrumb [aria-current="page"] {
  color: var(--color-text);
  font-weight: 500;
}

/* ========== 搜索 ========== */
.search-box {
  position: relative;
  width: 100%;
  max-width: 40rem;
}

.search-box__input {
  width: 100%;
  min-height: 3.25rem;
  padding: 0.75rem 2.75rem 0.75rem 2.85rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  color: var(--color-text);
  box-shadow: var(--shadow-sm);
  transition:
    border-color var(--duration-fast) var(--ease-out),
    box-shadow var(--duration-fast) var(--ease-out);
  -webkit-appearance: none;
  appearance: none;
}

.search-box__input::placeholder {
  color: var(--color-text-faint);
}

.search-box__input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: var(--shadow-focus);
}

.search-box__icon {
  position: absolute;
  left: 1rem;
  top: 50%;
  transform: translateY(-50%);
  width: 1.15rem;
  height: 1.15rem;
  color: var(--color-text-faint);
  pointer-events: none;
}

.search-box__clear {
  position: absolute;
  right: 0.55rem;
  top: 50%;
  transform: translateY(-50%);
  display: none;
  place-items: center;
  width: 2.25rem;
  height: 2.25rem;
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
}

.search-box__clear.is-visible {
  display: grid;
}

.search-box__clear:hover {
  background: var(--color-primary-soft);
  color: var(--color-primary);
}

.search-meta {
  margin: var(--space-4) 0 var(--space-6);
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

.mark-hit {
  background: var(--color-accent-soft);
  color: inherit;
  border-radius: 3px;
  padding: 0 0.12em;
}

/* ========== 空状态 / 错误 ========== */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: var(--space-4);
  padding: var(--space-14, var(--space-12)) var(--space-6);
  border: 1px dashed var(--color-border);
  border-radius: var(--radius-lg);
  background: color-mix(in srgb, var(--color-surface) 65%, transparent);
}

.empty-state__icon {
  width: 2.75rem;
  height: 2.75rem;
  color: var(--color-text-faint);
  opacity: 0.85;
}

.empty-state__title {
  margin: 0;
  font-size: var(--text-xl);
}

.empty-state__desc {
  margin: 0;
  max-width: 28rem;
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  line-height: var(--leading-relaxed);
}

/* ========== Loading 骨架 ========== */
.skeleton-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 17.5rem), 1fr));
  gap: var(--space-6);
}

.skeleton-card {
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  overflow: hidden;
  background: var(--color-surface);
}

.skeleton-card__cover {
  aspect-ratio: 16 / 10;
  background: linear-gradient(
    90deg,
    var(--color-border) 0%,
    color-mix(in srgb, var(--color-border) 40%, var(--color-surface)) 50%,
    var(--color-border) 100%
  );
  background-size: 200% 100%;
  animation: shimmer 1.4s ease-in-out infinite;
}

.skeleton-card__body {
  padding: var(--space-5);
  display: grid;
  gap: var(--space-3);
}

.skeleton-line {
  height: 0.85rem;
  border-radius: 4px;
  background: linear-gradient(
    90deg,
    var(--color-border) 0%,
    color-mix(in srgb, var(--color-border) 40%, var(--color-surface)) 50%,
    var(--color-border) 100%
  );
  background-size: 200% 100%;
  animation: shimmer 1.4s ease-in-out infinite;
}

.skeleton-line--title {
  height: 1.15rem;
  width: 75%;
}

.skeleton-line--short {
  width: 40%;
}

@keyframes shimmer {
  0% {
    background-position: 100% 0;
  }
  100% {
    background-position: -100% 0;
  }
}

/* ========== 返回顶部 ========== */
.back-to-top {
  position: fixed;
  right: max(var(--space-5), env(safe-area-inset-right, 0px));
  bottom: max(var(--space-5), env(safe-area-inset-bottom, 0px));
  z-index: var(--z-top);
  display: grid;
  place-items: center;
  width: var(--tap-min);
  height: var(--tap-min);
  border-radius: var(--radius-full);
  background: color-mix(in srgb, var(--color-surface) 92%, transparent);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-md);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition:
    opacity var(--duration) var(--ease-out),
    visibility var(--duration) var(--ease-out),
    transform var(--duration) var(--ease-out),
    border-color var(--duration-fast) var(--ease-out),
    color var(--duration-fast) var(--ease-out);
  -webkit-tap-highlight-color: transparent;
}

.back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  color: var(--color-primary);
  border-color: color-mix(in srgb, var(--color-primary) 35%, var(--color-border));
}

.back-to-top svg {
  width: 1.2rem;
  height: 1.2rem;
}

/* ========== 筛选条 ========== */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  margin-bottom: var(--space-8);
}

.filter-bar__info {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

.filter-bar__info strong {
  color: var(--color-text);
  font-weight: 600;
}

/* ========== 分页 ========== */
.pagination {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: var(--space-2);
  margin-top: var(--space-10);
}

.pagination__btn {
  min-width: var(--tap-min);
  height: var(--tap-min);
  padding: 0 var(--space-3);
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  font-weight: 500;
  transition:
    border-color var(--duration-fast) var(--ease-out),
    color var(--duration-fast) var(--ease-out),
    background var(--duration-fast) var(--ease-out);
}

.pagination__btn:hover:not(:disabled) {
  border-color: var(--color-border-strong);
  color: var(--color-primary);
}

.pagination__btn.is-active {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #fff;
}

.pagination__btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

/* ========== 上下篇导航 ========== */
.article-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4);
  margin-top: var(--space-12);
  padding-top: var(--space-8);
  border-top: 1px solid var(--color-border);
}

.article-nav__link {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding: var(--space-5);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  text-decoration: none;
  color: inherit;
  transition:
    border-color var(--duration-fast) var(--ease-out),
    box-shadow var(--duration-fast) var(--ease-out),
    background var(--duration-fast) var(--ease-out);
  -webkit-tap-highlight-color: transparent;
}

.article-nav__link:hover {
  border-color: color-mix(in srgb, var(--color-primary) 32%, var(--color-border));
  box-shadow: var(--shadow-sm);
  color: inherit;
}

.article-nav__link--next {
  text-align: right;
  align-items: flex-end;
}

.article-nav__label {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  font-weight: 500;
  text-transform: none;
}

.article-nav__title {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text);
  line-height: var(--leading-snug);
}

.article-nav__link:hover .article-nav__title {
  color: var(--color-primary);
}

.article-nav__placeholder {
  opacity: 0.4;
  pointer-events: none;
}

@media (max-width: 560px) {
  .article-nav {
    grid-template-columns: 1fr;
    gap: var(--space-3);
  }

  .article-nav__link--next {
    text-align: left;
    align-items: flex-start;
  }

  .article-nav__link {
    padding: var(--space-4);
  }
}

/* ========== 提示条 ========== */
.notice {
  display: flex;
  gap: var(--space-3);
  align-items: flex-start;
  padding: var(--space-4) var(--space-5);
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: var(--leading-relaxed);
}

.notice--accent {
  background: var(--color-accent-soft);
  border-color: color-mix(in srgb, var(--color-accent) 32%, transparent);
}

.notice--primary {
  background: var(--color-primary-soft);
  border-color: color-mix(in srgb, var(--color-primary) 22%, transparent);
}

.notice strong {
  color: var(--color-text);
}

/* ========== 主题切换图标 ========== */
.theme-toggle .icon-sun,
.theme-toggle .icon-moon {
  width: 1.15rem;
  height: 1.15rem;
}

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

[data-theme="dark"] .theme-toggle .icon-moon {
  display: block;
}

:root:not([data-theme="dark"]) .theme-toggle .icon-sun {
  display: block;
}

:root:not([data-theme="dark"]) .theme-toggle .icon-moon {
  display: none;
}

/* 移动端组件微调 */
@media (max-width: 640px) {
  .article-card__body {
    padding: var(--space-4);
    gap: var(--space-2);
  }

  .article-card__title {
    font-size: var(--text-base);
  }

  .article-card__summary {
    -webkit-line-clamp: 2;
    font-size: 0.8125rem;
  }

  .category-card {
    padding: var(--space-5);
  }

  .empty-state {
    padding: var(--space-10) var(--space-4);
  }

  .filter-bar {
    margin-bottom: var(--space-6);
    gap: var(--space-3);
  }

  .search-box__input {
    min-height: 3rem;
    font-size: 1rem; /* 防止 iOS 聚焦时页面缩放 */
  }

  .breadcrumb {
    margin-bottom: var(--space-5);
    font-size: var(--text-xs);
  }

  .back-to-top {
    right: max(var(--space-4), env(safe-area-inset-right, 0px));
    bottom: max(var(--space-4), env(safe-area-inset-bottom, 0px));
  }
}