/* The BIRD tool layout — one system for the interactive tools.
 *
 * Every tool page that adopts it has the same shape:
 *
 *   .bt-wrap
 *     .bt-head      eyebrow · serif title with one red italic word · thesis
 *     .bt-grid      two columns, inputs on the left (sticky), results right
 *       .bt-panel   h2 · .bt-sub · .bt-field (label + .bt-val, input, .bt-note) · .bt-divider
 *       results     .bt-headline (navy, red top line) · .bt-stats > .bt-stat
 *                   .bt-card (charts, tables) · .bt-takeaway
 *     .bt-more      "Go deeper" links
 *     .bt-foot      BIRD · nlebird.com
 *
 * Chart colours come from js/bird-charts.js, so every chart reads the same.
 * Tokens match styles.css: navy #16265C, red #C8202E, paper #F4EFE6.
 * (Nirav, 16 Oct 2026) */

.bt-page{
  --bt-navy:#16265C; --bt-navy-deep:#0E1A40; --bt-red:#C8202E; --bt-red-deep:#A81A25;
  --bt-paper:#F4EFE6; --bt-cream:#EDE5D6; --bt-card:#fff; --bt-line:#E3DAC9;
  --bt-ink:#1b1c22; --bt-muted:#6b5f52;
  --bt-serif:'Fraunces',Georgia,serif; --bt-sans:'DM Sans',system-ui,-apple-system,sans-serif;
  margin:0; background:var(--bt-paper); color:var(--bt-ink); font-family:var(--bt-sans); line-height:1.5;
}
.bt-page *,.bt-page *::before,.bt-page *::after{box-sizing:border-box}
.bt-wrap{max-width:1120px;margin:0 auto;padding:44px 24px 72px}

/* the opening */
.bt-head{margin:0 0 36px;max-width:760px}
.bt-eye{display:flex;align-items:center;gap:10px;font:700 11.5px var(--bt-sans);letter-spacing:.18em;text-transform:uppercase;color:var(--bt-red);margin:0 0 14px}
.bt-eye::before{content:"";width:28px;height:2px;background:var(--bt-red);flex:none}
.bt-head h1{font-family:var(--bt-serif);font-weight:600;font-size:clamp(32px,4.6vw,50px);line-height:1.06;letter-spacing:-.01em;color:var(--bt-navy);margin:0 0 16px}
.bt-head h1 em{font-style:italic;color:var(--bt-red)}
.bt-thesis{font-size:17px;color:var(--bt-muted);margin:0;max-width:660px}
.bt-thesis strong{color:var(--bt-ink);font-weight:700}

/* two columns */
.bt-grid{display:grid;grid-template-columns:320px minmax(0,1fr);gap:28px;align-items:start}
.bt-grid > *{min-width:0}   /* a wide table scrolls inside its card, never the page */

/* inputs */
.bt-panel{background:var(--bt-card);border:1px solid var(--bt-line);border-top:4px solid var(--bt-navy);border-radius:14px;padding:24px 24px 26px;position:sticky;top:20px}
.bt-panel h2{font-family:var(--bt-serif);font-size:19px;font-weight:600;color:var(--bt-navy);margin:0 0 4px}
.bt-sub{font-size:12.5px;color:var(--bt-muted);margin:0 0 20px}
.bt-field{margin:0 0 18px}
.bt-field label{display:flex;justify-content:space-between;align-items:baseline;gap:10px;font-size:13px;font-weight:700;color:var(--bt-ink);margin:0 0 6px}
.bt-val{font-weight:700;color:var(--bt-red);font-size:13.5px;white-space:nowrap}
.bt-note{font-size:11.5px;color:var(--bt-muted);margin-top:5px;font-style:italic}
.bt-divider{height:1px;background:var(--bt-line);margin:22px 0}
.bt-page input[type=range]{width:100%;-webkit-appearance:none;appearance:none;height:5px;border-radius:4px;background:var(--bt-cream);outline:none;margin:4px 0}
.bt-page input[type=range]::-webkit-slider-thumb{-webkit-appearance:none;width:18px;height:18px;border-radius:50%;background:var(--bt-red);border:3px solid #fff;box-shadow:0 0 0 1px var(--bt-red);cursor:pointer}
.bt-page input[type=range]::-moz-range-thumb{width:18px;height:18px;border-radius:50%;background:var(--bt-red);border:3px solid #fff;box-shadow:0 0 0 1px var(--bt-red);cursor:pointer}
.bt-page input[type=range]:focus-visible{outline:2px solid var(--bt-navy);outline-offset:4px}

/* results */
.bt-headline{background:linear-gradient(160deg,var(--bt-navy) 0%,var(--bt-navy-deep) 100%);border-top:4px solid var(--bt-red);border-radius:16px;padding:28px 30px;color:#fff;margin:0 0 22px}
.bt-tag{font-size:11.5px;font-weight:700;letter-spacing:.14em;text-transform:uppercase;color:#FF9AA2;margin:0 0 10px}
.bt-big{font-family:var(--bt-serif);font-size:clamp(26px,3.6vw,40px);font-weight:600;line-height:1.15;margin:0 0 8px}
.bt-big .bt-num,.bt-big em{color:#FFD0D4;font-style:normal}
.bt-small{font-size:14.5px;color:rgba(255,255,255,.86);max-width:580px;margin:0}

.bt-stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:14px;margin:0 0 22px}
.bt-stat{background:var(--bt-card);border:1px solid var(--bt-line);border-radius:12px;padding:16px 18px}
.bt-k{font-size:11px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--bt-muted)}
.bt-v{font-family:var(--bt-serif);font-size:24px;font-weight:600;margin-top:4px;color:var(--bt-navy)}
.bt-v.bt-red{color:var(--bt-red)}

.bt-card{background:var(--bt-card);border:1px solid var(--bt-line);border-radius:14px;padding:22px 24px 14px;margin:0 0 22px;overflow-x:auto}
.bt-card h3{font-family:var(--bt-serif);font-size:18px;font-weight:600;color:var(--bt-navy);margin:0 0 3px}
.bt-desc{font-size:13px;color:var(--bt-muted);margin:0 0 16px}
.bt-card canvas{max-height:320px}
.bt-legend{display:flex;gap:18px;flex-wrap:wrap;margin-top:14px;padding-top:14px;border-top:1px solid var(--bt-line)}
.bt-legend span{display:inline-flex;align-items:center;gap:7px;font-size:12.5px;color:var(--bt-muted)}
.bt-legend i{width:11px;height:11px;border-radius:3px;display:inline-block}

.bt-card table{width:100%;border-collapse:collapse;font-size:13px}
.bt-card th{text-align:right;font-weight:700;font-size:11px;letter-spacing:.05em;text-transform:uppercase;color:var(--bt-muted);padding:8px 10px;border-bottom:2px solid var(--bt-line);white-space:nowrap}
.bt-card td{text-align:right;padding:9px 10px;border-bottom:1px solid var(--bt-line);white-space:nowrap}
.bt-card th:first-child,.bt-card td:first-child{text-align:left}
.bt-card tr:last-child td{border-bottom:none}

.bt-btn{display:inline-flex;align-items:center;gap:8px;background:var(--bt-navy);color:#fff;border:0;border-radius:999px;padding:11px 20px;font:700 14px var(--bt-sans);cursor:pointer;margin:0 0 22px}
.bt-btn:hover{background:var(--bt-red)}
.bt-btn:focus-visible{outline:2px solid var(--bt-red);outline-offset:3px}

.bt-takeaway{background:var(--bt-cream);border-left:4px solid var(--bt-red);border-radius:0 12px 12px 0;padding:22px 26px;margin:0 0 22px}
.bt-takeaway p{font-size:15px;line-height:1.65;margin:0 0 12px}
.bt-takeaway p:last-child{margin:0}
.bt-takeaway strong{color:var(--bt-navy)}
.bt-sign{font-family:var(--bt-serif);font-style:italic;font-size:17px;color:var(--bt-red)}

.bt-more{margin-top:30px;font-size:13.5px;color:var(--bt-muted)}
.bt-more a{color:var(--bt-red);font-weight:700;text-decoration:none}
.bt-more a:hover{text-decoration:underline}
.bt-more .bt-sep{color:#C8B79E;margin:0 6px}
.bt-foot{margin-top:36px;padding-top:18px;border-top:1px solid var(--bt-line);font-size:12px;letter-spacing:.12em;text-transform:uppercase;color:var(--bt-muted)}

@media(max-width:860px){.bt-grid{grid-template-columns:minmax(0,1fr)}.bt-panel{position:static}}
@media(max-width:560px){.bt-wrap{padding:28px 16px 56px}.bt-headline{padding:22px 20px}.bt-card{padding:18px 16px 10px}}