/* PasteDiff — Monospace editorial (ink on cream). Style ≠ recolor of sisters. */
:root {
  --bg: #f7f3ea;
  --paper: #fffcf5;
  --ink: #1a1a1a;
  --muted: #5c574e;
  --line: #d9d2c3;
  --hair: #cfc7b6;
  --accent: #1a1a1a;
  --add-bg: #e7f2e7;
  --add-ink: #1e5c2e;
  --del-bg: #f6e6e4;
  --del-ink: #8b2e24;
  --focus: #3a5a8c;
  --radius: 2px;
  --page-max: 72rem;
  --serif: Georgia, "Times New Roman", "Songti SC", "Noto Serif SC", serif;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  --text-base: 1rem;
  --text-sm: 0.875rem;
  --text-xs: 0.75rem;
  --safe-t: env(safe-area-inset-top, 0px);
  --safe-b: env(safe-area-inset-bottom, 0px);
}
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
html[lang^="zh"] body { line-height: 1.65; }
body {
  margin: 0;
  font-family: var(--sans);
  font-size: var(--text-base);
  line-height: 1.7;
  color: var(--ink);
  background: var(--bg);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}
body.editorial {
  background:
    linear-gradient(90deg, transparent 47px, rgba(26,26,26,0.04) 47px, rgba(26,26,26,0.04) 48px, transparent 48px),
    var(--bg);
  background-attachment: local;
}
a { color: var(--ink); }
a:hover { text-decoration: underline; }
.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 100;
  background: var(--ink); color: var(--paper); padding: 0.5rem 0.75rem;
}
.skip-link:focus { left: 0.5rem; top: 0.5rem; }
.wrap {
  max-width: var(--page-max);
  margin: 0 auto;
  padding: 0 1.25rem 2.5rem;
  padding-top: max(0.35rem, var(--safe-t));
  padding-bottom: max(2.5rem, var(--safe-b));
}

/* —— Masthead: print rule, editorial —— */
.mast {
  display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between;
  gap: 0.5rem 0.75rem;
  padding: 0.85rem 0 0.9rem;
  border-bottom: 2px solid var(--ink);
  margin-bottom: 1.1rem;
  position: relative;
}
.brand a {
  display: flex; align-items: center; gap: 0.55rem;
  text-decoration: none; color: inherit;
}
.brand-mark {
  display: block;
  width: 32px;
  height: 32px;
  flex: 0 0 auto;
  flex-shrink: 0;
  align-self: center;
  border-radius: 2px;
}
.brand-name {
  font-family: var(--serif);
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  white-space: nowrap;
}
.brand small {
  display: block;
  font-family: var(--mono);
  font-size: var(--text-xs);
  color: var(--muted);
  letter-spacing: 0.04em;
  margin-top: 0.1rem;
}
.top-actions {
  display: flex; flex-wrap: wrap; align-items: center; gap: 0.35rem 0.4rem;
  justify-content: flex-end;
}
.lang-switch { display: inline-flex; gap: 0.15rem; border: 1px solid var(--line); border-radius: var(--radius); }
.lang-btn[aria-pressed="true"] { background: var(--ink); color: var(--paper); }

.btn {
  display: inline-flex; align-items: center; justify-content: center;
  gap: 0.35rem; min-height: 44px; padding: 0.45rem 0.85rem;
  font-family: var(--mono); font-size: var(--text-sm);
  letter-spacing: 0.02em;
  border: 1px solid var(--ink); border-radius: var(--radius);
  background: var(--paper); color: var(--ink); cursor: pointer;
  text-decoration: none; white-space: nowrap;
}
.btn:hover { background: var(--bg); text-decoration: none; }
.btn:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }
.btn-primary { background: var(--ink); color: var(--paper); font-weight: 600; }
.btn-primary:hover { background: #333; color: var(--paper); }
.btn-secondary { background: var(--paper); }
.btn-ghost { border-color: transparent; background: transparent; }
.btn-ghost:hover { border-color: var(--line); background: var(--paper); }
.btn-sm { min-height: 36px; padding: 0.3rem 0.65rem; font-size: var(--text-xs); }

/* Header XOR — hard */
.nav-toggle,
.btn.nav-toggle { display: none; }
.nav-guides {
  display: flex; flex-wrap: wrap; align-items: center; gap: 0.15rem 0.55rem;
}
.nav-guides a {
  font-family: var(--mono); font-size: var(--text-sm);
  color: var(--muted); text-decoration: none; padding: 0.35rem 0.4rem;
  border-radius: var(--radius);
}
.nav-guides a:hover { color: var(--ink); background: rgba(26,26,26,0.05); }
@media (min-width: 900px) {
  .nav-toggle,
  .btn.nav-toggle { display: none !important; }
  .nav-guides { display: flex !important; position: static; }
}
@media (max-width: 899px) {
  .nav-toggle,
  .btn.nav-toggle { display: inline-flex !important; }
  .nav-guides {
    display: none; position: absolute; right: 0; top: calc(100% + 0.35rem);
    flex-direction: column; align-items: stretch; gap: 0;
    min-width: 12rem; padding: 0.35rem;
    background: var(--paper); border: 1px solid var(--ink);
    border-radius: var(--radius); z-index: 40;
    box-shadow: 0 8px 24px rgba(26,26,26,0.08);
  }
  .nav-guides.is-open { display: flex; }
  .nav-guides a { padding: 0.55rem 0.7rem; }
}
.top-converter-short { display: none; }
@media (max-width: 430px) {
  .top-converter-full { display: none; }
  .top-converter-short { display: inline; }
  .mast { flex-direction: column; align-items: stretch; }
  .top-actions { justify-content: space-between; }
}

/* —— Editorial title —— */
.kicker {
  font-family: var(--mono); font-size: var(--text-xs);
  letter-spacing: 0.14em; text-transform: uppercase; color: var(--muted);
  margin: 0 0 0.35rem;
}
h1 {
  font-family: var(--serif);
  font-size: clamp(1.85rem, 3.2vw, 2.65rem);
  font-weight: 700; letter-spacing: -0.02em; line-height: 1.15;
  margin: 0 0 0.45rem; color: var(--ink);
}
.lead {
  font-size: 1.05rem; color: var(--muted); max-width: 42rem;
  margin: 0 0 0.85rem;
}
.trust-line {
  display: flex; flex-wrap: wrap; gap: 0.45rem 0.85rem; align-items: center;
  font-family: var(--mono); font-size: var(--text-xs);
  color: var(--muted); margin: 0 0 1.15rem;
  padding-bottom: 0.85rem; border-bottom: 1px solid var(--hair);
}
.trust-line .chip {
  border: 1px solid var(--line); padding: 0.2rem 0.45rem; border-radius: var(--radius);
  background: var(--paper);
}
.session-chip { font-family: var(--mono); font-size: var(--text-xs); color: var(--muted); }

/* —— Sticky compare bar —— */
.compare-bar {
  position: sticky; top: 0; z-index: 30;
  display: flex; flex-wrap: wrap; align-items: center; gap: 0.45rem 0.65rem;
  padding: 0.55rem 0.65rem;
  background: rgba(247, 243, 234, 0.96);
  border: 1px solid var(--ink);
  border-radius: var(--radius);
  margin-bottom: 0.85rem;
  backdrop-filter: none; /* no glass */
}
.compare-bar .opts {
  display: flex; flex-wrap: wrap; align-items: center; gap: 0.45rem 0.85rem;
  margin-left: auto;
}
.compare-bar label {
  display: inline-flex; align-items: center; gap: 0.35rem;
  font-family: var(--mono); font-size: var(--text-sm); color: var(--muted);
  cursor: pointer; min-height: 44px;
}
.compare-bar input[type="checkbox"] { width: 1rem; height: 1rem; accent-color: var(--ink); }
.view-seg {
  display: inline-flex; border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden;
}
.view-seg button {
  border: 0; background: transparent; min-height: 36px; padding: 0.3rem 0.65rem;
  font-family: var(--mono); font-size: var(--text-xs); cursor: pointer; color: var(--muted);
}
.view-seg button[aria-pressed="true"] { background: var(--ink); color: var(--paper); }

/* —— Paste columns hero (UNIQUE layout) —— */
.paste-stage {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  border: 1px solid var(--ink);
  background: var(--paper);
  margin-bottom: 0.85rem;
}
.paste-col {
  display: flex; flex-direction: column; min-width: 0;
  border-right: 1px solid var(--ink);
}
.paste-col:last-child { border-right: 0; }
.paste-head {
  display: flex; align-items: baseline; justify-content: space-between;
  gap: 0.5rem; padding: 0.55rem 0.75rem;
  border-bottom: 1px solid var(--hair);
  background: var(--bg);
}
.paste-head h2 {
  margin: 0; font-family: var(--serif); font-size: 1.05rem; font-weight: 700;
}
.paste-head .meta {
  font-family: var(--mono); font-size: var(--text-xs); color: var(--muted);
}
.paste-col textarea {
  flex: 1; width: 100%; min-height: 22rem;
  border: 0; resize: vertical; padding: 0.85rem 0.9rem;
  font-family: var(--mono); font-size: 0.9rem; line-height: 1.55;
  color: var(--ink); background: var(--paper);
  tab-size: 2;
}
.paste-col textarea:focus { outline: none; box-shadow: inset 0 0 0 2px var(--focus); }
.paste-col textarea::placeholder { color: #9a9386; }
@media (max-width: 760px) {
  .paste-stage { grid-template-columns: 1fr; }
  .paste-col { border-right: 0; border-bottom: 1px solid var(--ink); }
  .paste-col:last-child { border-bottom: 0; }
  .paste-col textarea { min-height: 14rem; }
}

/* —— Diff ribbon —— */
.diff-ribbon {
  border: 1px solid var(--ink);
  background: var(--paper);
  margin-bottom: 1.25rem;
}
.diff-ribbon-head {
  display: flex; flex-wrap: wrap; align-items: center; gap: 0.45rem 1rem;
  padding: 0.55rem 0.75rem;
  border-bottom: 1px solid var(--hair);
  background: var(--bg);
}
.diff-ribbon-head h2 {
  margin: 0; font-family: var(--serif); font-size: 1.05rem;
}
.diff-stats {
  display: flex; flex-wrap: wrap; gap: 0.45rem 0.75rem;
  font-family: var(--mono); font-size: var(--text-sm);
}
.diff-stats .add { color: var(--add-ink); }
.diff-stats .del { color: var(--del-ink); }
.diff-stats .same { color: var(--muted); }
.diff-body {
  max-height: min(28rem, 55vh);
  overflow: auto;
  font-family: var(--mono); font-size: 0.85rem; line-height: 1.5;
}
.diff-body.empty {
  padding: 1.5rem 1rem; color: var(--muted); text-align: center;
  font-family: var(--serif); font-style: italic; font-size: 1rem;
}
.diff-line {
  display: grid; grid-template-columns: 3.2rem 1.4rem 1fr;
  gap: 0; padding: 0.05rem 0.5rem 0.05rem 0;
  white-space: pre-wrap; word-break: break-word;
  border-bottom: 1px solid rgba(217,210,195,0.45);
}
.diff-line .ln { color: #9a9386; text-align: right; padding-right: 0.45rem; user-select: none; }
.diff-line .mark { text-align: center; user-select: none; }
.diff-line.add { background: var(--add-bg); color: var(--add-ink); }
.diff-line.del { background: var(--del-bg); color: var(--del-ink); }
.diff-line.same { color: var(--ink); }
.diff-line .tok-ins { background: rgba(30,92,46,0.22); border-radius: 1px; }
.diff-line .tok-del { background: rgba(139,46,36,0.22); text-decoration: line-through; border-radius: 1px; }

/* Split view */
.split-diff {
  display: grid; grid-template-columns: 1fr 1fr; gap: 0;
}
.split-diff .pane {
  border-right: 1px solid var(--hair); max-height: min(28rem, 55vh); overflow: auto;
  font-family: var(--mono); font-size: 0.85rem; line-height: 1.5;
}
.split-diff .pane:last-child { border-right: 0; }
.split-diff .diff-line { grid-template-columns: 3.2rem 1fr; }
@media (max-width: 760px) {
  .split-diff { grid-template-columns: 1fr; }
  .split-diff .pane { border-right: 0; border-bottom: 1px solid var(--hair); max-height: 16rem; }
}

/* Proof + SEO */
.proof {
  border: 1px solid var(--line); padding: 0.65rem 0.85rem; margin: 1.25rem 0;
  background: var(--paper); border-radius: var(--radius);
}
.proof summary {
  font-family: var(--mono); font-size: var(--text-sm); cursor: pointer;
  min-height: 44px; display: flex; align-items: center;
}
.proof ol { margin: 0.45rem 0 0; padding-left: 1.25rem; color: var(--muted); }
.seo-block { margin: 1.75rem 0; }
.seo-block h2 {
  font-family: var(--serif); font-size: 1.45rem; margin: 0 0 0.65rem;
  padding-bottom: 0.35rem; border-bottom: 1px solid var(--hair);
}
.seo-copy p, .seo-copy li { font-size: var(--text-base); color: var(--muted); }
.seo-copy p { margin: 0 0 0.75rem; }
.guide-cards {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(14rem, 1fr)); gap: 0.55rem;
  margin-top: 0.85rem;
}
.guide-card {
  display: block; padding: 0.85rem 0.9rem; text-decoration: none; color: inherit;
  background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius);
}
.guide-card:hover { border-color: var(--ink); text-decoration: none; }
.guide-card strong {
  display: block; font-family: var(--serif); font-size: 1.05rem; margin-bottom: 0.25rem;
}
.guide-card span { font-size: var(--text-sm); color: var(--muted); }
.faq details {
  border-bottom: 1px solid var(--hair); padding: 0.35rem 0;
}
.faq summary {
  font-weight: 600; cursor: pointer; min-height: 44px;
  display: flex; align-items: center; font-family: var(--serif);
}
.faq details p { margin: 0.35rem 0 0.65rem; color: var(--muted); font-size: var(--text-base); }

/* —— Footer 3-col (hard) —— */
.site-footer {
  margin-top: 2.5rem; padding-top: 1.35rem; padding-bottom: 0.35rem;
  border-top: 2px solid var(--ink);
  font-size: var(--text-sm); color: var(--muted);
  width: 100%;
}
.site-footer a { color: var(--ink); text-decoration: none; }
.site-footer a:hover { text-decoration: underline; }
.footer-grid {
  display: grid; grid-template-columns: 1fr; gap: 1.25rem 1.5rem;
  width: 100%; align-items: start;
}
.footer-col { min-width: 0; }
.footer-col h4 {
  margin: 0 0 0.45rem; font-family: var(--serif); font-size: 1rem; color: var(--ink);
}
.footer-col ul {
  list-style: none; margin: 0; padding: 0;
  display: flex; flex-direction: column; gap: 0.35rem; align-items: flex-start;
}
.footer-copy { margin: 0 0 0.4rem; }
.footer-meta {
  display: flex; flex-wrap: wrap; justify-content: space-between; gap: 0.35rem;
  margin-top: 1.15rem; padding-top: 0.75rem; border-top: 1px solid var(--hair);
  font-family: var(--mono); font-size: var(--text-xs);
}
@media (min-width: 700px) {
  .footer-grid {
    grid-template-columns: minmax(12rem, 1.4fr) minmax(8rem, 0.9fr) minmax(9rem, 1.1fr);
    gap: 1.5rem 2rem;
  }
}

/* Legal / article pages */
.article { max-width: 42rem; padding: 0.5rem 0 1.5rem; }
.article h1 { font-size: 2rem; }
.article h2 {
  font-family: var(--serif); font-size: 1.2rem; margin: 1.5rem 0 0.55rem;
  border-bottom: 1px solid var(--hair); padding-bottom: 0.25rem;
}
.article p, .article li { color: var(--muted); }
.hidden { display: none !important; }
.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0); border: 0;
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition: none !important; scroll-behavior: auto !important; }
}

/* UX-OPT-2026-10-20 */
.limit-note {
  margin: 0.35rem 0 0;
  font-size: 0.8125rem;
  line-height: 1.35;
  color: var(--muted, #64748b);
  max-width: 36rem;
}
.limit-note strong { color: var(--ink, #0f172a); font-weight: 600; }
.ux-banner {
  display: none;
  margin: 0.75rem 0;
  padding: 0.65rem 0.9rem;
  border-radius: 10px;
  font-size: 0.875rem;
  line-height: 1.4;
  border: 1px solid transparent;
}
.ux-banner.is-on { display: block; }
.ux-banner.is-ok {
  background: color-mix(in srgb, #10b981 12%, transparent);
  border-color: color-mix(in srgb, #10b981 35%, transparent);
  color: var(--ink, #065f46);
}
.ux-banner.is-err {
  background: color-mix(in srgb, #ef4444 10%, transparent);
  border-color: color-mix(in srgb, #ef4444 30%, transparent);
  color: var(--ink, #991b1b);
}
.ux-banner .ux-banner-actions { display: flex; flex-wrap: wrap; gap: 0.4rem; margin-top: 0.45rem; }
.drop-sample-prominent,
.dropzone .drop-sample,
.drop-actions .drop-ghost,
.dropzone .sample-link,
.drop-strip .drop-ghost {
  font-weight: 600 !important;
  text-decoration: underline;
  text-underline-offset: 3px;
}
body {
  padding-bottom: max(1.5rem, env(safe-area-inset-bottom));
}
@media (max-width: 480px) {
  body { padding-bottom: max(var(--sc-fb-pad, 72px), env(safe-area-inset-bottom)); }
  .batch-bar, #batchBar, .action-bar {
    padding-right: 4.25rem; /* leave room for feedback FAB */
  }
  .tool-stage, .paste-stage, .desk, .crt-bench, .studio, main {
    overflow-x: clip;
  }
}