:root {
  color-scheme: light;
  --bg: #f5f7f8;
  --panel: #ffffff;
  --panel-2: #f8fafb;
  --ink: #17212b;
  --muted: #667085;
  --faint: #8a94a3;
  --line: #e2e7ec;
  --line-strong: #cbd3db;
  --signal: #176b59;
  --signal-hover: #105545;
  --signal-soft: #eaf4f0;
  --thu: #72277f;
  --pku: #b02f3e;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

* { box-sizing: border-box; }
html { background: var(--bg); scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--bg); font-family: var(--sans); -webkit-font-smoothing: antialiased; }
a { color: inherit; }
button, input { font: inherit; }
button { color: inherit; }
.skip-link { position: fixed; z-index: 100; top: 8px; left: 8px; padding: 10px 14px; color: #fff; background: var(--signal); border-radius: 6px; transform: translateY(-160%); }
.skip-link:focus { transform: none; }

.compare-bar { position: sticky; z-index: 30; top: 0; height: 64px; display: grid; grid-template-columns: 200px 1fr auto; align-items: stretch; background: rgba(255,255,255,.96); border-bottom: 1px solid var(--line); backdrop-filter: blur(12px); }
.compare-brand { display: flex; align-items: center; gap: 11px; padding: 0 22px; text-decoration: none; }
.compare-brand > span { position: relative; display: block; width: 29px; height: 15px; }
.compare-brand i { position: absolute; top: 3px; width: 9px; height: 9px; border-radius: 50%; }
.compare-brand i:first-child { left: 1px; background: var(--thu); }
.compare-brand i:nth-child(2) { right: 1px; background: var(--pku); }
.compare-brand b { position: absolute; left: 8px; top: 7px; width: 13px; height: 1px; background: var(--line-strong); transform: rotate(-16deg); }
.compare-brand strong { font-size: 21px; font-weight: 750; letter-spacing: -.03em; }
.compare-bar-path { display: flex; align-items: center; padding: 0 16px; color: var(--muted); font-size: 13px; }
.compare-bar nav { display: flex; align-items: stretch; padding-right: 10px; }
.compare-bar nav a { position: relative; display: grid; place-items: center; min-width: 64px; padding: 0 13px; color: var(--muted); text-decoration: none; font-size: 14px; }
.compare-bar nav a:hover, .compare-bar nav a:focus-visible { color: var(--ink); background: var(--panel-2); outline: 0; }
.compare-bar nav a[aria-current] { color: var(--signal); font-weight: 650; }
.compare-bar nav a[aria-current]::after { content: ""; position: absolute; right: 13px; bottom: 0; left: 13px; height: 2px; background: var(--signal); }

main { width: min(1180px, calc(100% - 40px)); margin: 0 auto; padding: 30px 0 64px; }
.compare-hero { display: grid; grid-template-columns: minmax(0, 1fr) minmax(300px, 440px); gap: 44px; align-items: end; padding: 10px 2px 28px; border-bottom: 1px solid var(--line); }
.compare-hero-index { display: none; }
.compare-hero-copy p, .compare-select header > span, .results-head span, .section-head > span, .compare-next > div > span { display: block; margin: 0 0 8px; color: var(--signal); font-size: 13px; font-weight: 650; }
.compare-hero h1 { margin: 0; font-size: clamp(30px, 3.2vw, 42px); font-weight: 700; line-height: 1.2; letter-spacing: -.025em; }
.compare-hero-note { color: var(--muted); font-size: 14px; line-height: 1.75; }
.compare-hero-note p { margin: 0; }
.compare-hero-note a { display: inline-block; margin-top: 12px; color: var(--signal); font-size: 13px; text-decoration: none; }
.compare-hero-note a:hover { text-decoration: underline; }

.compare-select { margin-top: 24px; padding: 24px; background: var(--panel); border: 1px solid var(--line); border-radius: 12px; box-shadow: 0 1px 2px rgba(16,24,40,.04); }
.compare-select > header { display: grid; grid-template-columns: minmax(0, .75fr) minmax(300px, 1fr); gap: 28px; align-items: end; margin-bottom: 20px; }
.compare-select header > span { grid-column: 1 / -1; margin-bottom: -18px; }
.compare-select h2, .results-head h2 { margin: 0; font-size: 24px; line-height: 1.3; letter-spacing: -.02em; }
.compare-select header > p { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.65; }
.compare-pickers { display: grid; grid-template-columns: minmax(0, 1fr) 52px minmax(0, 1fr); align-items: center; gap: 12px; }
.compare-picker { min-width: 0; overflow: visible; background: var(--panel); border: 1px solid var(--line-strong); border-radius: 10px; }
.picker-code { height: 42px; display: flex; align-items: center; justify-content: space-between; padding: 0 14px; color: var(--muted); background: var(--panel-2); border-bottom: 1px solid var(--line); border-radius: 10px 10px 0 0; font-size: 13px; }
.picker-code b { color: var(--signal); font-size: 12px; font-weight: 650; }
.picker-search { position: relative; padding: 16px; }
.picker-search label { display: block; margin-bottom: 8px; color: var(--ink); font-size: 13px; font-weight: 600; }
.picker-search input { width: 100%; height: 46px; padding: 0 13px; color: var(--ink); background: #fff; border: 1px solid var(--line-strong); border-radius: 7px; outline: 0; font-size: 15px; }
.picker-search input::placeholder { color: #98a2b3; }
.picker-search input:focus { border-color: var(--signal); box-shadow: 0 0 0 3px rgba(23,107,89,.12); }
.picker-drop { position: absolute; z-index: 20; top: 94px; right: 16px; left: 16px; max-height: 330px; overflow: auto; background: var(--panel); border: 1px solid var(--line); border-radius: 8px; box-shadow: 0 16px 40px rgba(16,24,40,.15); }
.picker-result { width: 100%; display: grid; grid-template-columns: auto minmax(0,1fr) auto; gap: 10px; align-items: center; min-height: 58px; padding: 9px 12px; color: var(--ink); background: #fff; border: 0; border-bottom: 1px solid var(--line); text-align: left; cursor: pointer; }
.picker-result:last-child { border-bottom: 0; }
.picker-result:hover, .picker-result[aria-selected="true"] { background: var(--signal-soft); }
.picker-result-name { min-width: 0; overflow: hidden; white-space: nowrap; text-overflow: ellipsis; font-size: 14px; font-weight: 600; }
.picker-result-name em { margin-left: 6px; color: var(--muted); font-size: 11px; font-style: normal; font-weight: 400; }
.picker-result-meta { color: var(--muted); font-size: 11px; line-height: 1.4; text-align: right; }
.picker-empty { padding: 18px; color: var(--muted); font-size: 13px; line-height: 1.6; }
.school { display: inline-grid; place-items: center; min-width: 50px; height: 24px; padding: 0 8px; border-radius: 999px; font-size: 11px; }
.school.thu { color: var(--thu); background: rgba(114,39,127,.08); }
.school.pku { color: var(--pku); background: rgba(176,47,62,.08); }
.school.none { color: var(--faint); background: #f1f3f5; }
.picker-selected { min-height: 128px; padding: 18px; }
.picked-main { display: grid; grid-template-columns: minmax(0,1fr) auto; gap: 12px; align-items: start; }
.picked-main h3 { margin: 12px 0 5px; overflow-wrap: anywhere; font-size: 23px; line-height: 1.2; letter-spacing: -.02em; }
.picked-main p { margin: 0; color: var(--muted); font-size: 12px; line-height: 1.55; }
.picked-change { padding: 7px 11px; color: var(--muted); background: #fff; border: 1px solid var(--line-strong); border-radius: 6px; cursor: pointer; font-size: 12px; }
.picked-change:hover { color: var(--signal); border-color: var(--signal); }
.compare-swap { width: 42px; height: 42px; display: grid; place-items: center; margin: auto; color: var(--signal); background: #fff; border: 1px solid var(--line-strong); border-radius: 50%; cursor: pointer; font-size: 18px; }
.compare-swap span { display: none; }
.compare-swap:hover:not(:disabled) { color: #fff; background: var(--signal); border-color: var(--signal); }
.compare-swap:disabled { color: var(--faint); background: var(--panel-2); cursor: default; }
.compare-status { min-height: 42px; display: flex; align-items: center; margin-top: 16px; padding: 10px 13px; color: var(--muted); background: var(--signal-soft); border-radius: 7px; font-size: 13px; line-height: 1.5; }
.compare-status::before { content: ""; width: 7px; height: 7px; flex: 0 0 auto; margin-right: 9px; background: var(--signal); border-radius: 50%; }
.compare-status.is-error { color: var(--pku); background: rgba(176,47,62,.07); }
.compare-status.is-error::before { background: var(--pku); }

.compare-results { margin-top: 24px; padding: 24px; background: var(--panel); border: 1px solid var(--line); border-radius: 12px; box-shadow: 0 1px 2px rgba(16,24,40,.04); }
.results-head { display: flex; align-items: end; justify-content: space-between; gap: 24px; padding-bottom: 20px; border-bottom: 1px solid var(--line); }
.results-actions { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 8px; }
.results-actions button, .compare-next a { min-height: 38px; padding: 0 13px; color: var(--ink); background: #fff; border: 1px solid var(--line-strong); border-radius: 6px; text-decoration: none; cursor: pointer; font-size: 13px; }
.results-actions button:first-child { color: #fff; background: var(--signal); border-color: var(--signal); }
.results-actions button:hover, .compare-next a:hover, .compare-next a:focus-visible { color: var(--signal); background: var(--signal-soft); border-color: var(--signal); outline: 0; }
.results-actions button:first-child:hover { color: #fff; background: var(--signal-hover); }
.compare-verdict { display: grid; grid-template-columns: 100px 1fr; gap: 20px; margin: 20px 0; padding: 18px; background: var(--signal-soft); border: 1px solid #cfe4dc; border-radius: 8px; }
.compare-verdict span { color: var(--signal); font-size: 13px; font-weight: 650; }
.compare-verdict p { margin: 0; font-size: 16px; line-height: 1.6; }
.compare-ledger { margin-top: 30px; }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 20px; margin-bottom: 14px; }
.section-head > span { margin: 0; }
.section-head h3, .compare-next h3 { margin: 0; font-size: 20px; letter-spacing: -.015em; }
.metric-head, .metric-row { display: grid; grid-template-columns: minmax(120px,1fr) 120px minmax(130px,.8fr) 120px minmax(120px,1fr); align-items: center; border-top: 1px solid var(--line); }
.metric-head { min-height: 60px; background: var(--panel-2); border: 1px solid var(--line); border-radius: 8px 8px 0 0; }
.metric-head a { padding: 0 12px; font-size: 16px; font-weight: 650; text-decoration: none; }
.metric-head a:last-child { text-align: right; }
.metric-head span { color: var(--faint); text-align: center; font-size: 12px; }
.metric-row { min-height: 58px; }
.metric-row > b { font-size: 19px; font-weight: 650; }
.metric-row > b:last-child { text-align: right; }
.metric-row > span { color: var(--muted); text-align: center; font-size: 12px; }
.metric-bar { height: 6px; overflow: hidden; background: #edf0f2; border-radius: 999px; }
.metric-bar i { display: block; height: 100%; background: var(--signal); border-radius: inherit; }
.metric-bar.right { transform: scaleX(-1); }
.scope-note { margin: 14px 0 0; color: var(--muted); font-size: 12px; line-height: 1.65; }
.evidence-grid { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 16px; margin-top: 28px; }
.evidence-card { min-width: 0; min-height: 230px; padding: 20px; background: #fff; border: 1px solid var(--line); border-radius: 9px; }
.evidence-path { grid-column: 1 / -1; min-height: 190px; }
.evidence-k { display: flex; justify-content: space-between; gap: 18px; color: var(--muted); font-size: 12px; }
.evidence-k span:first-child { color: var(--signal); font-weight: 650; }
.evidence-k span:last-child { text-align: right; }
.evidence-card h3 { margin: 20px 0 10px; font-size: 19px; }
.evidence-card > p { color: var(--muted); font-size: 13px; line-height: 1.7; }
.evidence-strong { color: var(--ink) !important; font-size: 16px !important; }
.common-list { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 8px; margin-top: 14px; }
.common-list a { min-width: 0; display: grid; grid-template-columns: minmax(0,1fr) auto; gap: 8px; padding: 10px; background: var(--panel-2); border: 1px solid var(--line); border-radius: 6px; text-decoration: none; }
.common-list a:hover { border-color: var(--signal); }
.common-list strong { overflow: hidden; white-space: nowrap; text-overflow: ellipsis; font-size: 13px; }
.common-list span { color: var(--muted); font-size: 11px; }
.path-line { display: flex; align-items: center; gap: 8px; overflow-x: auto; padding: 14px 0 6px; }
.path-line a { flex: 0 0 auto; min-width: 122px; padding: 12px; background: var(--panel-2); border: 1px solid var(--line); border-radius: 7px; text-decoration: none; }
.path-line a:hover { border-color: var(--signal); }
.path-line a strong { display: block; font-size: 13px; }
.path-line a small { display: block; margin-top: 5px; color: var(--muted); font-size: 11px; }
.path-edge { flex: 0 0 auto; color: var(--signal); font-size: 11px; white-space: nowrap; }
.compare-next { display: grid; grid-template-columns: 1fr auto; align-items: end; gap: 24px; margin-top: 30px; padding-top: 22px; border-top: 1px solid var(--line); }
.compare-next > div:last-child { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 8px; }
.compare-next a { display: inline-flex; align-items: center; }
.compare-foot { display: flex; align-items: flex-start; justify-content: space-between; gap: 30px; margin-top: 24px; padding: 22px 2px; color: var(--muted); border-top: 1px solid var(--line); font-size: 12px; line-height: 1.7; }
.compare-foot p { margin: 0; }
.compare-foot a:hover { color: var(--signal); }

/* Data-product density ---------------------------------------------- */
.compare-hero { grid-template-columns: minmax(0,1fr) auto; gap: 24px; padding: 4px 2px 18px; }
.compare-hero h1 { font-size: 32px; }
.compare-hero-copy p { margin: 5px 0 0; color: var(--muted); font-size: 13px; font-weight: 400; }
.compare-hero-note { max-width: 390px; font-size: 12px; }
.compare-select { margin-top: 18px; padding: 20px; }
.compare-select > header { grid-template-columns: minmax(180px,.55fr) minmax(280px,1fr); gap: 20px; margin-bottom: 14px; }
.compare-select h2, .results-head h2 { font-size: 20px; }
.picker-code { height: 38px; }
.picker-selected { min-height: 112px; padding: 15px; }
.compare-status { min-height: 38px; margin-top: 12px; }
.compare-results { margin-top: 18px; padding: 20px; }
.results-head { padding-bottom: 14px; }
.compare-verdict { margin: 14px 0; padding: 14px; }
.compare-ledger { margin-top: 22px; }
.evidence-grid { margin-top: 22px; }

@media (max-width: 800px) {
  .compare-bar { height: 58px; grid-template-columns: 138px 1fr; }
  .compare-brand { padding: 0 14px; }
  .compare-brand > span { transform: scale(.9); transform-origin: left center; }
  .compare-brand strong { font-size: 19px; }
  .compare-bar-path { display: none; }
  .compare-bar nav { justify-content: flex-end; padding-right: 4px; }
  .compare-bar nav a { min-width: 50px; padding: 0 9px; font-size: 13px; }
  .compare-bar nav a[aria-current]::after { right: 8px; left: 8px; }
  main { width: min(100% - 28px, 1180px); padding-top: 22px; }
  .compare-hero { grid-template-columns: 1fr; gap: 12px; padding-bottom: 20px; }
  .compare-hero h1 { font-size: 27px; }
  .compare-hero-note { font-size: 13px; }
  .compare-select { margin-top: 16px; padding: 16px; }
  .compare-select > header { grid-template-columns: 1fr; gap: 7px; margin-bottom: 16px; }
  .compare-select header > span { grid-column: auto; margin-bottom: 0; }
  .compare-select h2, .results-head h2 { font-size: 21px; }
  .compare-pickers { grid-template-columns: 1fr; gap: 10px; }
  .compare-swap { width: 40px; height: 40px; transform: rotate(90deg); }
  .picker-selected { min-height: 116px; }
  .compare-results { margin-top: 16px; padding: 16px; }
  .results-head { align-items: flex-start; flex-direction: column; }
  .results-actions { width: 100%; justify-content: flex-start; }
  .compare-verdict { grid-template-columns: 1fr; gap: 8px; }
  .metric-head, .metric-row { grid-template-columns: minmax(82px,1fr) 48px minmax(76px,.9fr) 48px minmax(82px,1fr); }
  .metric-head a { padding: 0 7px; font-size: 13px; }
  .metric-row > b { font-size: 15px; }
  .metric-row > span { font-size: 10px; }
  .evidence-grid { grid-template-columns: 1fr; }
  .evidence-path { grid-column: auto; }
  .common-list { grid-template-columns: 1fr; }
  .compare-next { grid-template-columns: 1fr; }
  .compare-next > div:last-child { justify-content: flex-start; }
  .compare-foot { flex-direction: column; gap: 8px; }
}

@media (max-width: 500px) {
  .compare-bar nav a:nth-child(3), .compare-bar nav a:nth-child(4) { display: none; }
  .compare-hero-copy p { margin-bottom: 5px; }
  .picker-search, .picker-selected { padding: 14px; }
  .picker-drop { top: 91px; right: 14px; left: 14px; }
  .picker-result { grid-template-columns: auto minmax(0,1fr); }
  .picker-result-meta { display: none; }
  .picked-main h3 { font-size: 21px; }
  .results-actions button { flex: 1; padding-inline: 8px; }
  .metric-head, .metric-row { grid-template-columns: minmax(70px,1fr) 28px minmax(64px,.9fr) 28px minmax(70px,1fr); }
  .metric-bar { height: 4px; }
  .evidence-k { align-items: flex-start; }
  .evidence-k span:last-child { max-width: 64%; overflow-wrap: anywhere; }
}

@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

/* Keep the completed selection as a compact context bar above results. */
.compare-select.is-ready { padding: 14px 16px; }
.compare-select.is-ready > header { grid-template-columns: auto 1fr; align-items: center; gap: 14px; margin-bottom: 10px; }
.compare-select.is-ready > header p { font-size: 12px; line-height: 1.4; }
.compare-select.is-ready h2 { font-size: 16px; }
.compare-select.is-ready .picker-code { height: 30px; padding-inline: 10px; font-size: 11px; }
.compare-select.is-ready .picker-selected { min-height: 68px; padding: 10px; }
.compare-select.is-ready .picked-main { align-items: center; }
.compare-select.is-ready .picked-main h3 { margin: 4px 0 0; font-size: 17px; }
.compare-select.is-ready .picked-main p { margin-top: 3px; }
.compare-select.is-ready .compare-status { min-height: 30px; margin-top: 9px; padding: 5px 9px; background: transparent; font-size: 11px; }
.compare-select.is-ready .compare-status::before { width: 5px; height: 5px; }

@media (max-width: 800px) {
  .compare-select.is-ready { padding: 12px; }
  .compare-select.is-ready > header { display: flex; margin-bottom: 9px; }
  .compare-select.is-ready > header p { margin-left: auto; }
  .compare-select.is-ready .compare-pickers { grid-template-columns: minmax(0,1fr) 34px minmax(0,1fr); gap: 6px; }
  .compare-select.is-ready .compare-swap { width: 32px; height: 32px; transform: none; font-size: 15px; }
  .compare-select.is-ready .picker-selected { min-height: 62px; padding: 8px; }
  .compare-select.is-ready .picked-main { display: block; }
  .compare-select.is-ready .picked-main .school,
  .compare-select.is-ready .picked-main p { display: none; }
  .compare-select.is-ready .picked-main h3 { margin: 0 0 5px; overflow: hidden; white-space: nowrap; text-overflow: ellipsis; font-size: 15px; }
  .compare-select.is-ready .picked-change { padding: 5px 7px; font-size: 10px; }
}

@media (max-width: 500px) {
  .compare-select.is-ready > header p { display: none; }
  .compare-select.is-ready .compare-status { margin-top: 5px; padding-bottom: 0; }
}