/* ===== CSS 变量 ===== */
:root {
  --color-accent:     #2563EB;
  --color-accent-h:   #1d4ed8;
  --color-bg:         #ffffff;
  --color-text:       #1f2937;
  --color-text-muted: #6b7280;
  --color-border:     #e5e7eb;
  --color-card-bg:    #f9fafb;
  --font-system:      -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --radius:           8px;
  --shadow-sm:        0 1px 3px rgba(0,0,0,.08);
  --shadow-md:        0 4px 12px rgba(0,0,0,.10);
}

/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; }
body { margin: 0; font-family: var(--font-system); color: var(--color-text); background: var(--color-bg); line-height: 1.6; }
a { color: var(--color-accent); text-decoration: none; }
a:hover { color: var(--color-accent-h); }
img { max-width: 100%; height: auto; display: block; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0,0,0,0); }

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 8px 18px;
  border-radius: var(--radius);
  font-size: .9rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: background .15s, transform .1s;
}
.btn:active { transform: scale(.98); }
.btn--primary  { background: var(--color-accent); color: #fff; }
.btn--primary:hover { background: var(--color-accent-h); color: #fff; }
.btn--secondary { background: transparent; color: var(--color-accent); border: 1.5px solid var(--color-accent); }
.btn--secondary:hover { background: var(--color-accent); color: #fff; }
.btn--lg { padding: 12px 28px; font-size: 1rem; }

/* ===== Site Header ===== */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: #fff;
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
}
.site-header__inner {
  display: flex;
  align-items: center;
  height: 60px;
  gap: 24px;
}
.site-header__logo {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-text);
  white-space: nowrap;
}
.site-header__logo:hover { color: var(--color-accent); }

/* Nav */
.site-nav { margin-left: auto; }
.site-nav__list { display: flex; list-style: none; margin: 0; padding: 0; gap: 4px; }
.site-nav__link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 6px 14px;
  border-radius: var(--radius);
  font-size: .95rem;
  color: var(--color-text);
  background: none;
  border: none;
  cursor: pointer;
  font-family: inherit;
  font-weight: 500;
  transition: background .15s, color .15s;
}
.site-nav__link:hover { background: var(--color-card-bg); color: var(--color-accent); }
.site-nav__arrow { font-size: .7em; transition: transform .2s; }

/* Dropdown */
.site-nav__item--has-dropdown { position: relative; }
.site-nav__dropdown {
  display: none;
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-md);
  min-width: 160px;
  list-style: none;
  padding: 6px 0;
  margin: 0;
  z-index: 200;
}
.site-nav__item--has-dropdown:hover .site-nav__dropdown { display: block; }
.site-nav__item--has-dropdown:hover .site-nav__arrow { transform: rotate(180deg); }
.site-nav__dropdown li a {
  display: block;
  padding: 8px 16px;
  color: var(--color-text);
  font-size: .9rem;
}
.site-nav__dropdown li a:hover { background: var(--color-card-bg); color: var(--color-accent); }

/* Hamburger */
.site-header__hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
  margin-left: auto;
}
.site-header__hamburger span {
  display: block; width: 24px; height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: .3s;
}

/* ===== Cat Overlay (Mobile) ===== */
.cat-overlay {
  display: none;
  position: fixed; inset: 0; z-index: 500;
  background: rgba(0,0,0,.5);
}
.cat-overlay.is-open { display: flex; align-items: flex-start; }
.cat-overlay__inner {
  background: #fff;
  width: 100%; max-height: 90vh;
  overflow-y: auto;
  padding: 24px;
  margin-top: auto;
  border-radius: var(--radius) var(--radius) 0 0;
}
.cat-overlay__close {
  float: right;
  background: none; border: none; font-size: 1.4rem; cursor: pointer;
}
.cat-overlay__title { font-size: 1.2rem; margin: 0 0 16px; }
.cat-overlay__list { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.cat-overlay__list li a {
  display: block; padding: 12px; border: 1px solid var(--color-border);
  border-radius: var(--radius); color: var(--color-text); font-size: .95rem;
}
.cat-overlay__list li a:hover { background: var(--color-card-bg); border-color: var(--color-accent); color: var(--color-accent); }

/* ===== Site Search ===== */
.site-search__form {
  display: flex;
  max-width: 600px;
  margin: 0 auto;
  border: 2px solid var(--color-border);
  border-radius: 50px;
  overflow: hidden;
  background: #fff;
  transition: border-color .2s;
}
.site-search__form:focus-within { border-color: var(--color-accent); }
.site-search__input {
  flex: 1;
  border: none; outline: none;
  padding: 14px 20px;
  font-size: 1rem;
  font-family: inherit;
  background: transparent;
}
.site-search__btn {
  border-radius: 0 50px 50px 0;
  padding: 14px 28px;
}

/* ===== Section ===== */
.section-title {
  font-size: 1.4rem;
  margin: 0 0 20px;
  color: var(--color-text);
}
.empty-tip {
  color: var(--color-text-muted);
  text-align: center;
  padding: 40px 0;
  font-size: .95rem;
}

/* ===== Front Page ===== */
.front-hero {
  background: linear-gradient(135deg, #eff6ff 0%, #fff 100%);
  padding: 80px 0 60px;
  text-align: center;
}
.front-hero__title { font-size: 2.2rem; margin: 0 0 12px; color: var(--color-text); }
.front-hero__sub { color: var(--color-text-muted); font-size: 1.05rem; margin: 0 0 32px; }

.front-categories { padding: 56px 0; }
.cat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 16px;
}
.cat-card {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 20px;
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  color: var(--color-text);
  transition: box-shadow .2s, border-color .2s;
}
.cat-card:hover { border-color: var(--color-accent); box-shadow: var(--shadow-md); color: var(--color-text); }
.cat-card__icon { font-size: 2rem; }
.cat-card__name { font-weight: 600; font-size: 1rem; }
.cat-card__desc { font-size: .82rem; color: var(--color-text-muted); }
.cat-card__count { font-size: .8rem; color: var(--color-text-muted); margin-top: auto; }

.front-featured { padding: 56px 0; background: var(--color-card-bg); }
.front-blog { padding: 56px 0; }

/* ===== Tool Grid & Card ===== */
.tool-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  margin-top: 24px;
}
.tool-card {
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: box-shadow .2s, border-color .2s;
}
.tool-card:hover { box-shadow: var(--shadow-md); border-color: var(--color-accent); }

.tool-card__thumb { height: 100px; overflow: hidden; }
.tool-card__thumb-img { width: 100%; height: 100%; object-fit: cover; }
.tool-card__thumb--placeholder {
  display: flex; align-items: center; justify-content: center;
  height: 100px;
  background: linear-gradient(135deg, var(--color-accent) 0%, #60a5fa 100%);
  font-size: 2.5rem;
  color: #fff;
  font-weight: 700;
}

.tool-card__body { padding: 16px; display: flex; flex-direction: column; flex: 1; gap: 8px; }
.tool-card__title { margin: 0; font-size: .95rem; font-weight: 600; }
.tool-card__title a { color: var(--color-text); }
.tool-card__title a:hover { color: var(--color-accent); }
.tool-card__excerpt { margin: 0; font-size: .82rem; color: var(--color-text-muted); flex: 1; }

.tool-card__meta { display: flex; flex-wrap: wrap; gap: 6px; }
.tool-card__pricing, .tool-card__cat {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 50px;
  font-size: .75rem;
  font-weight: 600;
}
.tool-card__pricing--free     { background: #d1fae5; color: #065f46; }
.tool-card__pricing--freemium { background: #fef3c7; color: #92400e; }
.tool-card__pricing--paid     { background: #fee2e2; color: #991b1b; }
.tool-card__cat { background: #e0e7ff; color: #3730a3; }

.tool-card__actions { display: flex; gap: 8px; margin-top: auto; }
.tool-card__actions .btn { flex: 1; justify-content: center; font-size: .82rem; padding: 6px 10px; }

/* ===== Filters ===== */
.tool-filters { margin-bottom: 24px; }
.tool-filters__form {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: flex-end;
  padding: 16px;
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}
.tool-filters__label { display: block; font-size: .8rem; color: var(--color-text-muted); margin-bottom: 4px; }
.tool-filters__select, .tool-filters__input {
  height: 38px;
  padding: 0 12px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-size: .9rem;
  font-family: inherit;
  background: #fff;
  outline: none;
}
.tool-filters__select:focus, .tool-filters__input:focus { border-color: var(--color-accent); }
.tool-filters__group--search .tool-filters__input { min-width: 200px; }

/* ===== Pagination ===== */
.pagination-wrap { margin: 32px 0; }
.pagination__list { display: flex; flex-wrap: wrap; gap: 8px; list-style: none; padding: 0; margin: 0; justify-content: center; }
.pagination__item a, .pagination__item span {
  display: inline-flex; align-items: center; justify-content: center;
  width: 36px; height: 36px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-size: .9rem;
  color: var(--color-text);
  transition: .15s;
}
.pagination__item .current {
  background: var(--color-accent);
  color: #fff;
  border-color: var(--color-accent);
}
.pagination__item a:hover { border-color: var(--color-accent); color: var(--color-accent); }
.pagination__item .dots { border: none; }

/* ===== Tool Archive ===== */
.tools-archive { padding: 40px 0; }
.tools-archive .page-title { margin: 0 0 24px; font-size: 1.8rem; }

/* ===== Tool Detail ===== */
.single-tool { padding: 40px 0 60px; }
.tool-detail { max-width: 860px; }
.tool-detail__header { display: flex; gap: 24px; align-items: flex-start; margin-bottom: 32px; }
.tool-detail__thumb img { width: 120px; height: 120px; object-fit: cover; border-radius: var(--radius); border: 1px solid var(--color-border); }
.tool-detail__header-body { flex: 1; }
.tool-detail__title { font-size: 1.8rem; margin: 0 0 12px; }
.tool-detail__terms { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 16px; }

.tag {
  display: inline-block; padding: 3px 10px;
  border-radius: 50px; font-size: .8rem; font-weight: 600;
}
.tag--cat               { background: #e0e7ff; color: #3730a3; }
.tag--pricing.tag--free     { background: #d1fae5; color: #065f46; }
.tag--pricing.tag--freemium { background: #fef3c7; color: #92400e; }
.tag--pricing.tag--paid     { background: #fee2e2; color: #991b1b; }

.tool-detail__excerpt { font-size: 1.05rem; color: var(--color-text-muted); margin-bottom: 24px; line-height: 1.8; }
.tool-detail__content { margin-bottom: 24px; line-height: 1.8; }

.tool-detail__access-note {
  padding: 12px 16px;
  background: #eff6ff;
  border-left: 3px solid var(--color-accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  font-size: .9rem;
  margin-bottom: 24px;
}

.tool-detail__score {
  display: flex; align-items: center; gap: 10px;
  margin-bottom: 24px; font-size: .95rem;
}
.tool-detail__score-label { color: var(--color-text-muted); }
.tool-stars { font-size: 1.3rem; color: #f59e0b; letter-spacing: 2px; }
.tool-detail__score-num { color: var(--color-text-muted); font-size: .85rem; }

.tool-detail__alts { margin-bottom: 32px; }
.tool-detail__alts h3 { font-size: 1.05rem; margin-bottom: 12px; }
.tool-alts { list-style: none; padding: 0; margin: 0; display: flex; flex-wrap: wrap; gap: 10px; }
.tool-alts li a {
  display: inline-block; padding: 6px 14px;
  border: 1px solid var(--color-border); border-radius: var(--radius);
  font-size: .9rem; color: var(--color-text);
}
.tool-alts li a:hover { border-color: var(--color-accent); color: var(--color-accent); }

.tool-detail__comments { margin-top: 48px; padding-top: 32px; border-top: 1px solid var(--color-border); }

/* ===== Blog Grid ===== */
.blog-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.blog-card { padding: 20px; border: 1px solid var(--color-border); border-radius: var(--radius); }
.blog-card__title { font-size: 1rem; margin: 0 0 8px; }
.blog-card__date { font-size: .8rem; color: var(--color-text-muted); display: block; margin-bottom: 8px; }
.blog-card__excerpt { font-size: .88rem; color: var(--color-text-muted); margin: 0; }

/* ===== Footer ===== */
.site-footer { padding: 24px 0; border-top: 1px solid var(--color-border); margin-top: 60px; }
.site-footer__copy { margin: 0; font-size: .85rem; color: var(--color-text-muted); text-align: center; }

/* ===== Responsive ===== */
@media (max-width: 1024px) {
  .tool-grid { grid-template-columns: repeat(3, 1fr); }
}

@media (max-width: 768px) {
  .site-nav { display: none; }
  .site-nav.is-open { display: block; position: absolute; top: 60px; left: 0; right: 0; background: #fff; border-bottom: 1px solid var(--color-border); padding: 16px; }
  .site-nav__list { flex-direction: column; }
  .site-nav__dropdown { position: static; box-shadow: none; border: none; display: block !important; padding-left: 16px; }
  .site-header__hamburger { display: flex; }
  .tool-grid { grid-template-columns: repeat(2, 1fr); }
  .blog-grid { grid-template-columns: 1fr; }
  .cat-grid { grid-template-columns: repeat(2, 1fr); }
  .tool-detail__header { flex-direction: column; }
  .front-hero__title { font-size: 1.6rem; }
}

@media (max-width: 480px) {
  .tool-grid { grid-template-columns: 1fr; }
  .cat-grid { grid-template-columns: 1fr; }
  .tool-filters__form { flex-direction: column; }
  .tool-filters__group--search .tool-filters__input { width: 100%; }
}