:root {
  --ink: #18282f;
  --muted: #63747a;
  --surface: #ffffff;
  --canvas: #f4f7f5;
  --line: #d7e0dc;
  --teal: #06727a;
  --teal-deep: #064d57;
  --coral: #c85a49;
  --gold: #be8a31;
  --navy: #14262d;
  --shadow: 0 16px 36px rgba(24, 40, 47, 0.09);
}

* { box-sizing: border-box; }
html { background: var(--canvas); scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--canvas);
  font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  line-height: 1.55;
}
a { color: inherit; text-decoration: none; }
button, input { font: inherit; }
button { cursor: pointer; }
.site-header { background: var(--navy); color: #f8fbf9; border-bottom: 1px solid rgba(255,255,255,.14); }
.header-inner, .page-shell { width: min(1180px, calc(100% - 40px)); margin: 0 auto; }
.header-inner { min-height: 76px; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.brand { display: flex; align-items: center; gap: 12px; min-width: 0; }
.brand-symbol { width: 34px; height: 34px; border: 1px solid rgba(255,255,255,.6); display: grid; place-items: center; color: #f4c573; font-family: Georgia, serif; font-size: 20px; }
.brand-name { margin: 0; font-size: 15px; font-weight: 650; white-space: nowrap; }
.brand-subtitle { margin: 1px 0 0; color: #a9bcbe; font-size: 12px; }
.nav { display: flex; align-self: stretch; align-items: stretch; gap: 4px; }
.nav a { display: grid; place-items: center; min-width: 88px; padding: 0 14px; color: #c7d4d2; border-bottom: 2px solid transparent; font-size: 14px; }
.nav a:hover, .nav a[aria-current="page"] { color: #fff; border-bottom-color: #e7a46d; }
.page-hero { background: var(--navy); color: #fff; padding: 45px 0 50px; }
.hero-layout { display: grid; grid-template-columns: minmax(0, 1fr) auto; align-items: end; gap: 30px; }
.eyebrow { margin: 0 0 8px; color: #e7b66d; font-size: 13px; }
h1, h2, p { margin-top: 0; }
h1 { max-width: 760px; margin-bottom: 10px; font-size: clamp(30px, 4vw, 48px); line-height: 1.15; font-weight: 720; }
.hero-copy { max-width: 660px; margin-bottom: 0; color: #bed0cd; font-size: 16px; }
.hero-count { min-width: 122px; padding: 19px 20px 15px; border-left: 1px solid #637f7e; }
.hero-count b { display: block; font-size: 30px; line-height: 1; font-weight: 650; }
.hero-count span { display: block; margin-top: 5px; color: #b8cecb; font-size: 12px; }
.toolbar { display: flex; align-items: center; justify-content: space-between; gap: 20px; padding: 28px 0 22px; border-bottom: 1px solid var(--line); }
.filters { display: flex; flex-wrap: wrap; gap: 8px; }
.filter-chip { min-height: 34px; padding: 0 13px; border: 1px solid var(--line); background: transparent; color: #4c6267; border-radius: 5px; font-size: 13px; }
.filter-chip:hover, .filter-chip.is-active { background: var(--teal); border-color: var(--teal); color: #fff; }
.search-box { position: relative; width: min(100%, 290px); }
.search-box i { position: absolute; top: 50%; left: 12px; width: 16px; height: 16px; transform: translateY(-50%); color: #62787d; }
.search-box input { width: 100%; height: 38px; padding: 0 12px 0 37px; border: 1px solid var(--line); border-radius: 5px; outline: none; background: #fff; color: var(--ink); font-size: 13px; }
.search-box input:focus { border-color: var(--teal); box-shadow: 0 0 0 3px rgba(6,114,122,.12); }
.paper-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 22px; padding: 25px 0 58px; }
.paper-card { display: grid; grid-template-columns: 178px minmax(0, 1fr); min-height: 340px; overflow: hidden; background: var(--surface); border: 1px solid var(--line); border-radius: 7px; box-shadow: 0 2px 0 rgba(24,40,47,.025); transition: transform .18s ease, box-shadow .18s ease; }
.paper-card:hover { transform: translateY(-3px); box-shadow: var(--shadow); }
.paper-cover { position: relative; display: block; min-height: 100%; overflow: hidden; background: #e1e8e5; }
.paper-cover img { width: 100%; height: 100%; object-fit: cover; object-position: top center; transition: transform .25s ease; }
.paper-card:hover .paper-cover img { transform: scale(1.03); }
.cover-action { position: absolute; right: 10px; bottom: 10px; display: grid; width: 30px; height: 30px; place-items: center; background: rgba(20,38,45,.88); color: #fff; border-radius: 4px; }
.cover-action i { width: 16px; height: 16px; }
.paper-body { display: flex; min-width: 0; flex-direction: column; padding: 20px 20px 16px; }
.item-meta, .software-topline { display: flex; justify-content: space-between; gap: 10px; color: var(--teal); font-size: 12px; }
.item-meta span:last-child, .software-topline span:last-child { color: #7c8d91; }
.paper-body h2, .software-card h2 { margin: 8px 0 4px; font-size: 19px; line-height: 1.35; font-weight: 700; }
.original-title { min-height: 39px; margin-bottom: 11px; color: #7a8b8e; font-family: Georgia, "Times New Roman", serif; font-size: 12px; line-height: 1.55; }
.summary { margin-bottom: 13px; color: #43575c; font-size: 13px; }
.takeaway { display: grid; grid-template-columns: 30px 1fr; gap: 8px; margin-top: auto; padding-top: 10px; border-top: 1px solid #e3e9e5; color: #596c6f; font-size: 12px; }
.takeaway span { color: var(--coral); font-weight: 700; }
.takeaway p { margin: 0; }
.card-bottom { display: flex; align-items: flex-end; justify-content: space-between; gap: 12px; margin-top: 13px; }
.tag-list { display: flex; flex-wrap: wrap; gap: 5px; }
.tag-list span { padding: 3px 6px; background: #eaf2ef; color: #496366; border-radius: 3px; font-size: 11px; }
.text-link { display: inline-flex; align-items: center; gap: 4px; flex: 0 0 auto; color: var(--teal); font-size: 12px; font-weight: 650; }
.text-link i { width: 14px; height: 14px; }
.empty-state { padding: 60px 0; color: var(--muted); text-align: center; }
.software-main { padding: 28px 0 60px; }
.software-context { display: grid; grid-template-columns: 1.15fr .85fr; gap: 22px; margin-bottom: 23px; }
.context-note, .context-equation { padding: 21px; border: 1px solid var(--line); background: #fff; border-radius: 7px; }
.context-note h2 { margin-bottom: 6px; font-size: 15px; }
.context-note p { margin-bottom: 0; color: #53676b; font-size: 13px; }
.context-equation { display: flex; align-items: center; justify-content: space-between; gap: 15px; color: #586b6e; }
.context-equation code { color: var(--teal-deep); font-family: Georgia, serif; font-size: 25px; }
.context-equation span { max-width: 210px; font-size: 12px; }
.software-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 22px; }
.software-card { position: relative; min-height: 375px; padding: 26px; overflow: hidden; background: #fff; border: 1px solid var(--line); border-radius: 7px; box-shadow: 0 2px 0 rgba(24,40,47,.025); }
.software-card::after { position: absolute; right: -45px; bottom: -58px; width: 196px; height: 196px; border: 1px solid var(--accent); border-radius: 50%; content: ""; opacity: .1; }
.software-card.teal { --accent: var(--teal-deep); color: var(--teal-deep); }
.software-card.coral { --accent: #a74637; color: #a74637; }
.software-mark { display: grid; width: 62px; height: 62px; place-items: center; margin-bottom: 24px; color: #fff; background: var(--accent); border-radius: 5px; font-family: Georgia, serif; font-size: 19px; font-weight: 700; }
.software-topline { color: var(--accent); }
.software-description { max-width: 510px; margin: 13px 0; color: #42575c; font-size: 14px; }
.software-detail { max-width: 480px; margin-bottom: 19px; color: #738287; font-size: 12px; }
.download-row { position: relative; z-index: 1; display: flex; flex-wrap: wrap; gap: 9px; margin-top: auto; }
.download-link { display: inline-flex; align-items: center; min-height: 37px; gap: 7px; padding: 0 12px; color: var(--accent); border: 1px solid var(--accent); border-radius: 4px; font-size: 13px; font-weight: 650; }
.download-link.primary { color: #fff; background: var(--accent); }
.download-link i { width: 15px; height: 15px; }
.footer { border-top: 1px solid var(--line); color: #728285; background: #edf2ef; }
.footer-inner { display: flex; align-items: center; justify-content: space-between; min-height: 68px; gap: 18px; font-size: 12px; }
.footer-status { color: var(--teal); }
@media (max-width: 820px) {
  .header-inner, .page-shell { width: min(100% - 28px, 1180px); }
  .header-inner { min-height: 68px; }
  .brand-subtitle { display: none; }
  .nav a { min-width: 68px; padding: 0 9px; }
  .hero-layout, .software-context { grid-template-columns: 1fr; }
  .hero-count { padding: 0; border-left: 0; }
  .toolbar { align-items: stretch; flex-direction: column; }
  .search-box { width: 100%; }
  .paper-grid, .software-grid { grid-template-columns: 1fr; }
  .paper-card { grid-template-columns: 132px minmax(0, 1fr); }
  .footer-inner { align-items: flex-start; flex-direction: column; justify-content: center; padding: 13px 0; }
}
@media (max-width: 480px) {
  .brand-name { font-size: 13px; }
  .brand-symbol { width: 29px; height: 29px; }
  .nav a { min-width: 58px; font-size: 13px; }
  .page-hero { padding: 34px 0 38px; }
  h1 { font-size: 30px; }
  .paper-card { grid-template-columns: 108px minmax(0, 1fr); min-height: 312px; }
  .paper-body { padding: 16px 13px 13px; }
  .paper-body h2 { font-size: 16px; }
  .original-title { min-height: 0; max-height: 38px; overflow: hidden; }
  .summary { font-size: 12px; }
  .card-bottom { align-items: flex-start; flex-direction: column; }
  .software-card { padding: 21px; }
}