/* ─── TOKENS ─────────────────────────────────────── */
    :root {
      --ink:        #0d0f14;
      --ink-2:      #3a3d47;
      --ink-3:      #72757f;
      --paper:      #f7f6f2;
      --paper-2:    #eeecea;
      --accent:     #1a56e8;
      --accent-2:   #0e3ab5;
      --accent-warm:#d4520c;
      --good:       #2d9c4a;
      --sat:        #7cb93e;
      --mod:        #e8b820;
      --poor:       #e05a0c;
      --vpoor:      #c02020;
      --line:       rgba(13,15,20,.1);
      --line-2:     rgba(13,15,20,.06);
      --r:          12px;
      --r-lg:       20px;
      --shadow:     0 2px 12px rgba(0,0,0,.07), 0 1px 3px rgba(0,0,0,.05);
      --shadow-lg:  0 8px 40px rgba(0,0,0,.10), 0 2px 8px rgba(0,0,0,.07);
    }

    /* ─── RESET ──────────────────────────────────────── */
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    html { scroll-behavior: smooth; }
    body {
      font-family: 'DM Sans', sans-serif;
      font-size: 16px;
      line-height: 1.65;
      color: var(--ink);
      background: var(--paper);
      overflow-x: hidden;
    }
    img { max-width: 100%; display: block; }
    a { color: var(--accent); text-decoration: none; }
    a:hover { text-decoration: underline; }

    /* ─── TYPOGRAPHY ─────────────────────────────────── */
    .serif { font-family: 'DM Serif Display', Georgia, serif; }
    h1, h2, h3 { font-family: 'DM Serif Display', Georgia, serif; line-height: 1.2; }
    h2 { font-size: clamp(1.6rem, 3vw, 2.2rem); }
    h3 { font-size: 1.15rem; font-weight: 400; }
    .kicker {
      font-size: .72rem;
      letter-spacing: .14em;
      text-transform: uppercase;
      font-weight: 600;
      color: var(--accent);
    }

    /* ─── LAYOUT ─────────────────────────────────────── */
    .container { max-width: 960px; margin: 0 auto; padding: 0 24px; }
    .container-wide { max-width: 1120px; margin: 0 auto; padding: 0 24px; }
    section { padding: 72px 0; }

    /* ─── NAV ────────────────────────────────────────── */
    nav {
      position: sticky; top: 0; z-index: 100;
      background: rgba(247,246,242,.9);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--line);
    }
    .nav-inner {
      display: flex; align-items: center; justify-content: space-between;
      max-width: 960px; margin: 0 auto; padding: 0 24px; height: 52px;
    }
    .nav-brand { font-weight: 600; font-size: .95rem; color: var(--ink); letter-spacing: -.01em; }
    .nav-links { display: flex; gap: 28px; }
    .nav-links a { font-size: .85rem; color: var(--ink-2); font-weight: 500; }
    .nav-links a:hover { color: var(--accent); text-decoration: none; }

    /* ─── HERO ───────────────────────────────────────── */
    .hero {
      padding: 80px 0 60px;
      background: linear-gradient(175deg, #0d1a3a 0%, #162555 55%, #1a3070 100%);
      color: #fff;
      position: relative;
      overflow: hidden;
    }
    .hero::before {
      content: '';
      position: absolute; inset: 0;
      background: radial-gradient(ellipse 80% 60% at 50% -10%, rgba(80,130,255,.18), transparent);
      pointer-events: none;
    }
    /* subtle grid overlay */
    .hero::after {
      content: '';
      position: absolute; inset: 0;
      background-image: linear-gradient(rgba(255,255,255,.03) 1px, transparent 1px),
                        linear-gradient(90deg, rgba(255,255,255,.03) 1px, transparent 1px);
      background-size: 48px 48px;
      pointer-events: none;
    }
    .hero-content { position: relative; z-index: 1; text-align: center; }
    .hero-venue {
      display: inline-block;
      background: rgba(255,255,255,.1);
      border: 1px solid rgba(255,255,255,.18);
      border-radius: 50px;
      padding: 4px 16px;
      font-size: .78rem;
      letter-spacing: .08em;
      font-weight: 500;
      color: rgba(255,255,255,.85);
      margin-bottom: 24px;
    }
    .hero h1 {
      font-size: clamp(2rem, 5vw, 3.2rem);
      color: #fff;
      max-width: 800px;
      margin: 0 auto 10px;
      font-style: italic;
    }
    .hero-tagline {
      font-size: 1.05rem;
      color: rgba(255,255,255,.65);
      margin-bottom: 32px;
      font-weight: 300;
      letter-spacing: .01em;
    }
    .author-row {
      display: flex; flex-wrap: wrap; justify-content: center;
      gap: 6px 24px; margin-bottom: 8px;
    }
    .author-row a {
      color: rgba(255,255,255,.9);
      font-size: 1.05rem;
      font-weight: 500;
      border-bottom: 1px solid rgba(255,255,255,.25);
      padding-bottom: 1px;
    }
    .author-row a:hover { color: #fff; text-decoration: none; border-color: #fff; }
    .affiliation {
      font-size: .98rem;
      color: rgba(255,255,255,.5);
      margin-bottom: 36px;
      font-style: italic;
    }
    .cta-row {
      display: flex; flex-wrap: wrap; gap: 12px;
      justify-content: center;
    }
    .btn {
      display: inline-flex; align-items: center; gap: 7px;
      padding: 9px 22px;
      border-radius: 50px;
      font-size: .88rem;
      font-weight: 500;
      cursor: pointer;
      transition: all .18s;
      text-decoration: none;
    }
    .btn-primary {
      background: var(--accent);
      color: #fff;
      border: 1px solid var(--accent);
    }
    .btn-primary:hover { background: var(--accent-2); border-color: var(--accent-2); text-decoration: none; }
    .btn-outline {
      background: rgba(255,255,255,.08);
      color: rgba(255,255,255,.9);
      border: 1px solid rgba(255,255,255,.25);
    }
    .btn-outline:hover { background: rgba(255,255,255,.16); text-decoration: none; }
    .btn-ghost {
      background: rgba(255,255,255,.05);
      color: rgba(255,255,255,.55);
      border: 1px solid rgba(255,255,255,.12);
      cursor: default;
    }
    .btn svg { width: 16px; height: 16px; }

    /* ─── STATS BAR ──────────────────────────────────── */
    .stats-bar {
      background: var(--ink);
      color: #fff;
      padding: 0;
    }
    .stats-inner {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      max-width: 960px; margin: 0 auto;
    }
    .stat-cell {
      padding: 28px 24px;
      border-right: 1px solid rgba(255,255,255,.08);
      text-align: center;
    }
    .stat-cell:last-child { border-right: none; }
    .stat-num {
      font-family: 'DM Serif Display', serif;
      font-size: 2rem;
      color: #fff;
      display: block;
      line-height: 1;
      margin-bottom: 4px;
    }
    .stat-num span { font-size: 1.1rem; color: rgba(255,255,255,.5); }
    .stat-label { font-size: .78rem; color: rgba(255,255,255,.45); letter-spacing: .05em; text-transform: uppercase; }

    /* ─── ABSTRACT ───────────────────────────────────── */
    #abstract { background: var(--paper); }
    .abstract-card {
      background: #fff;
      border: 1px solid var(--line);
      border-radius: var(--r-lg);
      padding: 48px 52px;
      box-shadow: var(--shadow);
      position: relative;
    }
    .abstract-card::before {
      content: '"';
      font-family: 'DM Serif Display', serif;
      font-size: 9rem;
      color: var(--accent);
      opacity: .07;
      position: absolute; top: -10px; left: 24px;
      line-height: 1;
      pointer-events: none;
    }
    .abstract-text {
      font-size: 1.02rem;
      line-height: 1.78;
      color: var(--ink-2);
      max-width: 760px;
    }

    /* ─── SECTION HEADING ────────────────────────────── */
    .section-header { margin-bottom: 40px; }
    .section-header .kicker { margin-bottom: 6px; display: block; }

    .section-header-tight {
      margin-top: 40px;
      margin-bottom: 16px;
    }

    .section-title-sm {
      font-size: 1.3rem;
    }

    .section-lead {
      max-width: 820px;
      color: var(--ink-2);
      font-size: 1.02rem;
      line-height: 1.78;
      margin-top: 12px;
    }

    .paper-grid {
      display: grid;
      gap: 20px;
      margin-top: 10px;
    }

    .paper-grid-2 {
      grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .paper-card {
      background: #fff;
      border: 1px solid var(--line);
      border-radius: var(--r-lg);
      padding: 26px 28px;
      box-shadow: var(--shadow);
    }

    .paper-card h3 {
      font-family: 'DM Sans', sans-serif;
      font-size: .82rem;
      text-transform: uppercase;
      letter-spacing: .09em;
      color: var(--ink-3);
      font-weight: 600;
      margin-bottom: 12px;
    }

    .paper-card p {
      color: var(--ink-2);
      font-size: .98rem;
      line-height: 1.8;
      margin-bottom: 14px;
    }

    .paper-card p:last-child { margin-bottom: 0; }

    .paper-bullets {
      list-style: none;
      display: grid;
      gap: 10px;
      margin: 0;
      padding: 0;
    }

    .paper-bullets li {
      position: relative;
      padding-left: 18px;
      color: var(--ink-2);
      line-height: 1.7;
      font-size: .97rem;
    }

    .paper-bullets li::before {
      content: '';
      position: absolute;
      left: 0;
      top: .7em;
      width: 7px;
      height: 7px;
      border-radius: 50%;
      background: var(--accent);
    }

    .figure-pair {
      display: grid;
      grid-template-columns: repeat(2, minmax(0, 1fr));
      gap: 18px;
      align-items: start;
    }

    /* ─── DATASET ────────────────────────────────────── */
    #dataset { background: var(--paper-2); }
    .dataset-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 20px;
      margin-bottom: 32px;
    }
    .info-card {
      background: #fff;
      border: 1px solid var(--line);
      border-radius: var(--r);
      padding: 28px 28px 24px;
      box-shadow: var(--shadow);
    }
    .info-card h3 {
      font-size: .78rem;
      text-transform: uppercase;
      letter-spacing: .1em;
      color: var(--ink-3);
      margin-bottom: 12px;
      font-family: 'DM Sans', sans-serif;
      font-weight: 600;
    }
    .info-card ul { list-style: none; }
    .info-card ul li {
      font-size: .9rem;
      color: var(--ink-2);
      padding: 5px 0;
      border-bottom: 1px solid var(--line-2);
      display: flex; justify-content: space-between; gap: 12px;
    }
    .info-card ul li:last-child { border-bottom: none; }
    .info-card ul li strong { color: var(--ink); font-weight: 600; white-space: nowrap; }
    /* AQI band bar */
    .aqi-bands {
      display: flex; border-radius: 8px; overflow: hidden; height: 36px;
      margin-top: 16px; border: 1px solid var(--line);
    }
    .band {
      display: flex; align-items: center; justify-content: center;
      font-size: .72rem; font-weight: 600; color: #fff;
      flex-shrink: 0;
    }
    .band-good  { background: var(--good);  flex: 36; }
    .band-sat   { background: var(--sat);   flex: 31; }
    .band-mod   { background: var(--mod);   color: #333; flex: 16; }
    .band-poor  { background: var(--poor);  flex: 11; }
    .band-vpoor { background: var(--vpoor); flex: 6;  }
    .band-labels {
      display: flex;
      font-size: .7rem;
      color: var(--ink-3);
      margin-top: 6px;
    }
    .band-labels span { flex: 1; text-align: center; }
    /* seasonal bars */
    .season-row { margin-top: 8px; }
    .season-item { margin-bottom: 10px; }
    .season-item .s-head {
      display: flex; justify-content: space-between;
      font-size: .85rem; margin-bottom: 4px; color: var(--ink-2);
    }
    .s-head strong { color: var(--ink); }
    .s-bar-bg { background: var(--paper-2); border-radius: 4px; height: 8px; overflow: hidden; }
    .s-bar-fill { height: 100%; border-radius: 4px; }

    /* panorama image */
    .pano-wrap {
      border-radius: var(--r);
      overflow: hidden;
      border: 1px solid var(--line);
      box-shadow: var(--shadow-lg);
      position: relative;
      margin-top: 8px;
    }
    .pano-wrap img { width: 100%; object-fit: cover; display: block; }
    .pano-label {
      position: absolute; bottom: 0; left: 0; right: 0;
      background: linear-gradient(transparent, rgba(0,0,0,.6));
      color: rgba(255,255,255,.8);
      font-size: .78rem;
      padding: 20px 16px 10px;
    }

    /* ─── ARCHITECTURE ───────────────────────────────── */
    #architecture { background: var(--paper); }
    .arch-steps {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 16px;
      margin-bottom: 36px;
    }
    .step-card {
      background: #fff;
      border: 1px solid var(--line);
      border-radius: var(--r);
      padding: 24px 22px;
      box-shadow: var(--shadow);
      position: relative;
    }
    .step-num {
      width: 32px; height: 32px;
      background: var(--accent);
      color: #fff;
      border-radius: 50%;
      display: flex; align-items: center; justify-content: center;
      font-size: .8rem;
      font-weight: 700;
      margin-bottom: 14px;
    }
    .step-card h3 {
      font-family: 'DM Sans', sans-serif;
      font-size: .95rem;
      font-weight: 600;
      margin-bottom: 8px;
      color: var(--ink);
    }
    .step-card p { font-size: .87rem; color: var(--ink-2); line-height: 1.55; }
    .tag-row { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 12px; }
    .tag {
      background: var(--paper-2);
      border: 1px solid var(--line);
      border-radius: 4px;
      font-size: .72rem;
      font-weight: 500;
      color: var(--ink-2);
      padding: 2px 9px;
    }
    .tag-blue { background: #e8effe; color: var(--accent); border-color: #c5d4fc; }
    .arch-img-wrap {
      background: #fff;
      border: 1px solid var(--line);
      border-radius: var(--r-lg);
      overflow: hidden;
      box-shadow: var(--shadow-lg);
      padding: 24px;
    }
    .arch-img-wrap img { border-radius: 8px; }
    .arch-img-wrap figcaption {
      text-align: center;
      font-size: .8rem;
      color: var(--ink-3);
      margin-top: 12px;
    }

    /* ─── RESULTS ────────────────────────────────────── */
    #results { background: var(--paper-2); }
    .results-layout {
      display: grid;
      grid-template-columns: 1.2fr 1fr;
      gap: 24px;
      align-items: start;
    }
    .table-wrap {
      background: #fff;
      border: 1px solid var(--line);
      border-radius: var(--r);
      overflow: hidden;
      box-shadow: var(--shadow);
    }
    .table-wrap table {
      width: 100%;
      border-collapse: collapse;
      font-size: .88rem;
    }
    .table-wrap thead th {
      background: var(--ink);
      color: #fff;
      font-weight: 500;
      font-size: .78rem;
      letter-spacing: .05em;
      text-transform: uppercase;
      padding: 12px 16px;
      text-align: left;
    }
    .table-wrap thead th:not(:first-child) { text-align: right; }
    .table-wrap tbody tr { border-bottom: 1px solid var(--line-2); }
    .table-wrap tbody tr:last-child { border-bottom: none; }
    .table-wrap tbody td {
      padding: 11px 16px;
      color: var(--ink-2);
    }
    .table-wrap tbody td:not(:first-child) { text-align: right; font-variant-numeric: tabular-nums; }
    .table-wrap tbody tr.highlight-row {
      background: #f0f5ff;
    }
    .table-wrap tbody tr.highlight-row td {
      color: var(--ink);
      font-weight: 600;
    }
    .metric-cards {
      display: grid;
      grid-template-columns: repeat(2, minmax(0, 1fr));
      gap: 12px;
      align-self: start;
    }
    .metric-card {
      background: #fff;
      border: 1px solid var(--line);
      border-radius: var(--r);
      padding: 14px 16px;
      box-shadow: var(--shadow);
    }
    .metric-card .m-label { font-size: .68rem; text-transform: uppercase; letter-spacing: .09em; color: var(--ink-3); font-weight: 600; margin-bottom: 5px; }
    .metric-card .m-val {
      font-family: 'DM Serif Display', serif;
      font-size: 1.85rem;
      color: var(--ink);
      line-height: 1;
      margin-bottom: 4px;
    }
    .metric-card .m-delta {
      font-size: .74rem;
      color: var(--good);
      font-weight: 600;
    }
    .metric-card .m-note { font-size: .72rem; color: var(--ink-3); margin-top: 2px; }

    /* ─── ABLATION ───────────────────────────────────── */
    #ablation { background: var(--paper); }
    .ablation-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
    .abl-group h3 {
      font-family: 'DM Sans', sans-serif;
      font-size: .8rem;
      text-transform: uppercase;
      letter-spacing: .09em;
      color: var(--ink-3);
      font-weight: 600;
      margin-bottom: 12px;
    }
    .abl-row {
      display: flex; align-items: center; gap: 12px;
      padding: 9px 0;
      border-bottom: 1px solid var(--line-2);
      font-size: .87rem;
    }
    .abl-row:last-child { border-bottom: none; }
    .abl-name { flex: 1; color: var(--ink-2); }
    .abl-acc { width: 56px; text-align: right; font-weight: 600; color: var(--ink); font-variant-numeric: tabular-nums; }
    .abl-delta { width: 52px; text-align: right; font-size: .78rem; color: var(--poor); font-variant-numeric: tabular-nums; font-weight: 500; }
    .abl-row.best .abl-acc { color: var(--accent); }
    .abl-row.best .abl-delta { color: var(--good); }
    .bar-mini-wrap { width: 72px; }
    .bar-mini-bg { background: var(--paper-2); border-radius: 3px; height: 6px; overflow: hidden; }
    .bar-mini-fill { height: 100%; border-radius: 3px; background: var(--accent); opacity: .7; }
    .bar-mini-fill.best-bar { opacity: 1; }

    /* ─── SETUP ──────────────────────────────────────── */
    #setup { background: var(--paper-2); }
    .setup-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; align-items: start; }
    .setup-img-wrap {
      border-radius: var(--r);
      overflow: hidden;
      border: 1px solid var(--line);
      box-shadow: var(--shadow-lg);
    }
    .setup-img-wrap img { width: 100%; display: block; }
    .setup-img-wrap figcaption { font-size: .78rem; color: var(--ink-3); padding: 10px 14px; text-align: center; background: #fff; }

    /* gradcam */
    .gradcam-wrap {
      border-radius: var(--r);
      overflow: hidden;
      border: 1px solid var(--line);
      box-shadow: var(--shadow-lg);
    }
    .gradcam-wrap img { width: 100%; display: block; }
    .gradcam-wrap figcaption {
      background: #fff; padding: 10px 14px;
      font-size: .78rem; color: var(--ink-3); text-align: center;
    }

    /* ─── CONTRIBUTIONS ──────────────────────────────── */
    #contributions { background: var(--paper); }
    .contrib-list { display: flex; flex-direction: column; gap: 14px; }
    .contrib-item {
      background: #fff;
      border: 1px solid var(--line);
      border-left: 3px solid var(--accent);
      border-radius: 0 var(--r) var(--r) 0;
      padding: 18px 22px;
      box-shadow: var(--shadow);
      display: flex; gap: 18px; align-items: flex-start;
    }
    .contrib-num {
      font-family: 'DM Serif Display', serif;
      font-size: 1.5rem;
      color: var(--accent);
      opacity: .4;
      flex-shrink: 0;
      line-height: 1;
      min-width: 28px;
    }
    .contrib-body h3 {
      font-family: 'DM Sans', sans-serif;
      font-weight: 600;
      font-size: .95rem;
      margin-bottom: 5px;
    }
    .contrib-body p { font-size: .87rem; color: var(--ink-2); line-height: 1.55; }

    /* ─── COMPARISON TABLE (datasets) ───────────────── */
    .dataset-compare-wrap {
      background: #fff;
      border: 1px solid var(--line);
      border-radius: var(--r);
      overflow: hidden;
      box-shadow: var(--shadow);
      margin-top: 32px;
    }
    .dataset-compare-wrap table { width: 100%; border-collapse: collapse; font-size: .87rem; }
    .dataset-compare-wrap thead th {
      background: var(--paper-2);
      color: var(--ink-2);
      font-size: .75rem;
      letter-spacing: .07em;
      text-transform: uppercase;
      font-weight: 600;
      padding: 11px 16px;
      border-bottom: 1px solid var(--line);
      text-align: left;
    }
    .dataset-compare-wrap thead th:not(:first-child) { text-align: center; }
    .dataset-compare-wrap tbody tr { border-bottom: 1px solid var(--line-2); }
    .dataset-compare-wrap tbody td { padding: 10px 16px; color: var(--ink-2); }
    .dataset-compare-wrap tbody td:not(:first-child) { text-align: center; }
    .dataset-compare-wrap tbody tr.ours td { background: #f0f5ff; font-weight: 600; color: var(--ink); }
    .check { color: var(--good); font-size: 1rem; }
    .cross { color: var(--ink-3); }
    .dataset-caption { font-size: .78rem; color: var(--ink-3); padding: 10px 16px; border-top: 1px solid var(--line-2); }

    .contrib-list.compact .contrib-item {
      padding: 16px 20px;
    }

    .contrib-list.compact .contrib-body p {
      font-size: .92rem;
      line-height: 1.65;
    }

    .result-summary {
      max-width: 860px;
      margin-top: 12px;
      color: var(--ink-2);
      font-size: 1.01rem;
      line-height: 1.75;
    }

    .section-stack-tight {
      padding-top: 0;
      padding-bottom: 48px;
    }

    .section-stack-more {
      padding-top: 0;
      padding-bottom: 56px;
      background: var(--paper);
    }

    .figure-small {
      max-width: 560px;
      margin: 24px auto 0;
    }

    .footer-brand {
      margin-bottom: 6px;
    }

    .footer-brand strong {
      color: rgba(255,255,255,.75);
    }

    .footer-credit {
      margin-top: 12px;
      font-size: .75rem;
    }

    #reading-progress {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 4px;
      background: rgba(13, 15, 20, 0.06);
      z-index: 120;
    }

    #reading-progress-bar {
      width: 0%;
      height: 100%;
      background: linear-gradient(90deg, var(--accent), var(--accent-2));
      transition: width 120ms linear;
    }

    .back-to-top {
      position: fixed;
      right: 20px;
      bottom: 22px;
      width: 46px;
      height: 46px;
      border: 0;
      border-radius: 50%;
      background: var(--ink);
      color: #fff;
      box-shadow: var(--shadow-lg);
      display: flex;
      align-items: center;
      justify-content: center;
      cursor: pointer;
      z-index: 120;
      opacity: 0;
      transform: translateY(12px);
      pointer-events: none;
      transition: opacity 160ms ease, transform 160ms ease, background 160ms ease;
    }

    .back-to-top:hover {
      background: var(--accent);
    }

    .back-to-top.show {
      opacity: 1;
      transform: translateY(0);
      pointer-events: auto;
    }

    .back-to-top:focus-visible {
      outline: 2px solid rgba(26, 86, 232, 0.35);
      outline-offset: 2px;
    }

    /* ─── FOOTER ─────────────────────────────────────── */
    footer {
      background: var(--ink);
      color: rgba(255,255,255,.5);
      padding: 36px 0;
      text-align: center;
      font-size: .82rem;
    }
    footer a { color: rgba(255,255,255,.7); }

    /* ─── RESPONSIVE ─────────────────────────────────── */
    @media (max-width: 720px) {
      .stats-inner { grid-template-columns: 1fr 1fr; }
      .stat-cell { border-right: none; border-bottom: 1px solid rgba(255,255,255,.08); }
      .stat-cell:nth-child(odd) { border-right: 1px solid rgba(255,255,255,.08); }
      .dataset-grid { grid-template-columns: 1fr; }
      .arch-steps { grid-template-columns: 1fr; }
      .results-layout { grid-template-columns: 1fr; }
      .metric-cards { grid-template-columns: 1fr; }
      .paper-grid-2 { grid-template-columns: 1fr; }
      .figure-pair { grid-template-columns: 1fr; }
      .ablation-grid { grid-template-columns: 1fr; }
      .setup-grid { grid-template-columns: 1fr; }
      .abstract-card { padding: 28px 24px; }
      nav { display: none; }
    }
    @media (max-width: 520px) {
      .stats-inner { grid-template-columns: 1fr 1fr; }
      .cta-row { flex-direction: column; align-items: center; }
      .back-to-top {
        right: 14px;
        bottom: 14px;
        width: 42px;
        height: 42px;
      }
    }