:root{
    --froid:#0d6e78;        /* teal profond, accent rafraîchissement */
    --froid-clair:#e6f1f2;
    --chaud:#d97534;        /* ambre, accent chauffage (réversible) */
    --chaud-clair:#fbeee3;
    --ink:#15232b;          /* texte principal, cool near-black */
    --muted:#5f7079;        /* texte secondaire */
    --line:#dce5e7;
    --bg:#eef3f4;
    --card:#ffffff;
    --radius:16px;
  }
  *{box-sizing:border-box;margin:0;padding:0}
  body{
    font-family:'Instrument Sans',system-ui,sans-serif;
    background:linear-gradient(180deg,#eef3f4 0%,#e5edee 100%);
    background-attachment:fixed;
    color:var(--ink);
    line-height:1.5;
    -webkit-font-smoothing:antialiased;
    padding:24px 16px 64px;
  }
  .wrap{max-width:680px;margin:0 auto}
  header{margin:8px 0 28px}
  .eyebrow{
    font-size:13px;font-weight:600;letter-spacing:.08em;text-transform:uppercase;
    color:var(--froid);margin-bottom:10px;
  }
  h1{
    font-family:'Fraunces',Georgia,serif;
    font-weight:500;font-size:clamp(28px,6vw,40px);
    line-height:1.1;letter-spacing:-.01em;margin-bottom:12px;
  }
  .lede{color:var(--muted);font-size:16px;max-width:52ch}

  .card{
    background:var(--card);border:1px solid var(--line);border-radius:var(--radius);
    padding:24px;margin-bottom:20px;
  }

  /* Résultat — la signature */
  .result{
    background:linear-gradient(160deg,#0f7e88 0%,#0a565e 100%);
    color:#fff;border:none;overflow:hidden;position:relative;
    box-shadow:0 18px 40px -20px rgba(11,91,99,.65);
  }
  .result::before{
    content:"";position:absolute;top:-40%;right:-10%;width:280px;height:280px;
    background:radial-gradient(circle,rgba(255,255,255,.12) 0%,transparent 70%);pointer-events:none;
  }
  .result .label{font-size:13px;font-weight:600;letter-spacing:.06em;text-transform:uppercase;opacity:.8}
  .figure{display:flex;align-items:baseline;gap:10px;margin:6px 0 2px}
  .figure .kw{font-family:'Fraunces',serif;font-weight:600;font-size:clamp(48px,13vw,72px);line-height:1}
  .figure .unit{font-family:'Fraunces',serif;font-size:24px;opacity:.85}
  .btu{font-size:15px;opacity:.85}
  .badge{
    display:inline-flex;align-items:center;gap:8px;margin-top:18px;
    background:rgba(255,255,255,.14);border:1px solid rgba(255,255,255,.25);
    padding:8px 14px;border-radius:999px;font-weight:600;font-size:15px;
  }
  .badge small{font-weight:400;opacity:.8}
  /* bandeau chaud, visible seulement en réversible */
  .heat{
    margin-top:16px;padding-top:16px;border-top:1px solid rgba(255,255,255,.18);
    display:none;align-items:baseline;gap:8px;
  }
  .heat.on{display:flex}
  .heat .dot{width:9px;height:9px;border-radius:50%;background:var(--chaud);align-self:center}
  .heat .v{font-family:'Fraunces',serif;font-weight:600;font-size:22px;color:#ffd9bf}
  .heat .t{font-size:14px;opacity:.85}
  .result-note{
    margin-top:14px;font-size:13.5px;line-height:1.45;
    background:rgba(255,255,255,.12);border:1px solid rgba(255,255,255,.22);
    border-radius:10px;padding:11px 13px;color:#eaf6f7;
  }
  .result-note[hidden]{display:none}
  /* jauge modèle conseillé (signature) */
  .meter{margin-top:20px}
  .meter-head{display:flex;justify-content:space-between;align-items:baseline;gap:10px;margin-bottom:11px}
  .meter-label{font-size:12px;font-weight:600;letter-spacing:.05em;text-transform:uppercase;opacity:.8}
  .meter-val{font-family:'Fraunces',serif;font-weight:600;font-size:20px;white-space:nowrap}
  .meter-track{position:relative;height:6px;border-radius:999px;background:rgba(255,255,255,.18);margin:0 7px}
  .meter-fill{position:absolute;left:0;top:0;height:100%;border-radius:999px;
    background:linear-gradient(90deg,rgba(255,255,255,.4),#fff);transition:width .4s cubic-bezier(.4,0,.2,1)}
  .meter-knob{position:absolute;top:50%;width:16px;height:16px;border-radius:50%;background:#fff;
    transform:translate(-50%,-50%);box-shadow:0 2px 8px rgba(0,0,0,.4);transition:left .4s cubic-bezier(.4,0,.2,1)}
  .meter-scale{display:flex;justify-content:space-between;margin:10px 0 0;font-size:11px;opacity:.7}
  .meter-type{margin-top:8px;font-size:13px;opacity:.85;text-transform:capitalize}

  /* Formulaire */
  h2{font-family:'Fraunces',serif;font-weight:500;font-size:20px;margin-bottom:18px}
  .field{margin-bottom:18px}
  .field:last-child{margin-bottom:0}
  label{display:block;font-weight:600;font-size:15px;margin-bottom:7px}
  .hint{font-weight:400;color:var(--muted);font-size:13px}
  /* aide « ? » */
  .label-row{display:flex;align-items:center;gap:7px;margin-bottom:7px}
  .label-row label{margin-bottom:0}
  .help-btn{
    flex:0 0 auto;width:19px;height:19px;border-radius:50%;
    border:1px solid var(--line);background:#fff;color:var(--muted);
    font-family:inherit;font-size:12px;font-weight:700;line-height:1;cursor:pointer;
    display:inline-flex;align-items:center;justify-content:center;padding:0;transition:.12s;
  }
  .help-btn:hover{border-color:var(--froid);color:var(--froid)}
  .help-btn:focus-visible{outline:2px solid var(--froid);outline-offset:1px}
  .help-btn[aria-expanded="true"]{background:var(--froid);border-color:var(--froid);color:#fff}
  .help-text{
    font-size:13.5px;color:#3c5560;background:var(--froid-clair);
    border-radius:9px;padding:10px 12px;margin-bottom:9px;
  }
  .help-text[hidden]{display:none}
  .row{display:flex;gap:12px}
  .row .field{flex:1}
  input[type="number"],select{
    width:100%;font-family:inherit;font-size:16px;color:var(--ink);
    padding:11px 13px;border:1px solid var(--line);border-radius:10px;background:#fff;
    transition:border-color .12s,box-shadow .12s;
  }
  input[type="number"]:hover,select:hover{border-color:#aac3c5}
  input:focus,select:focus{outline:2px solid var(--froid);outline-offset:1px;border-color:var(--froid)}
  /* segmented (orientation, usage) */
  .seg{display:flex;gap:8px;flex-wrap:wrap}
  .seg input{position:absolute;opacity:0;width:0;height:0}
  .seg label{
    flex:1;min-width:fit-content;text-align:center;cursor:pointer;margin:0;font-weight:500;font-size:14px;
    padding:10px 12px;border:1px solid var(--line);border-radius:10px;background:#fff;transition:.12s;
  }
  .seg input:checked + label{background:var(--froid-clair);border-color:var(--froid);color:var(--froid)}
  .seg input:focus-visible + label{outline:2px solid var(--froid);outline-offset:1px}
  .seg.usage input:checked + label[for="usage-rev"]{background:var(--chaud-clair);border-color:var(--chaud);color:var(--chaud)}

  .disclaimer{
    background:var(--chaud-clair);border:1px solid #f0d9c6;border-radius:12px;
    padding:16px 18px;font-size:14px;color:#7a4a26;
  }
  .disclaimer strong{color:#5e3415}
  .cta{
    display:inline-block;margin-top:12px;background:var(--chaud);color:#fff;text-decoration:none;
    font-weight:600;font-size:15px;padding:11px 20px;border-radius:10px;
  }
  .sources{font-size:13px;color:var(--muted);margin-top:8px}
  .sources summary{cursor:pointer;font-weight:600;color:var(--ink)}
  .sources ul{margin:10px 0 0 18px}
  .sources li{margin-bottom:5px}
  /* contenu éditorial */
  .content{margin-top:6px}
  .content .answer-box{
    background:linear-gradient(180deg,#e8f3f4 0%,#fbfdfd 100%);
    border:1px solid #b7d6d9;border-left:5px solid var(--froid);
    border-radius:12px;padding:18px 22px;margin-bottom:26px;font-size:16px;color:#274049;
    box-shadow:0 12px 30px -14px rgba(13,110,120,.45);
  }
  .content .answer-box .ab-eyebrow{display:block;font-size:12px;font-weight:700;letter-spacing:.07em;
    text-transform:uppercase;color:var(--froid);margin-bottom:7px}
  .content .answer-box strong{color:var(--froid)}
  .content h2{font-family:'Fraunces',serif;font-weight:500;font-size:23px;line-height:1.15;margin:32px 0 12px;letter-spacing:-.01em}
  .content h3{font-size:16px;font-weight:600;margin:20px 0 6px}
  .content p{margin-bottom:14px;color:#33454d}
  .content ul{margin:0 0 14px 20px;color:#33454d}
  .content li{margin-bottom:7px}
  .content table{width:100%;border-collapse:collapse;margin:8px 0 20px;font-size:15px}
  .content th,.content td{text-align:left;padding:10px 12px;border-bottom:1px solid var(--line)}
  .content th{font-weight:600;background:#f3f8f8}
  /* duo sous / sur-dimensionnement */
  .duo{display:flex;gap:14px;margin:8px 0;flex-wrap:wrap}
  .duo-card{flex:1;min-width:220px;border:1px solid var(--line);border-radius:12px;padding:16px 18px;background:#fff}
  .duo-card .tag{display:inline-block;font-size:11px;font-weight:700;letter-spacing:.05em;text-transform:uppercase;padding:3px 9px;border-radius:999px;margin-bottom:9px}
  .duo-card h4{font-size:15px;font-weight:600;margin-bottom:6px}
  .duo-card.under .tag{background:var(--froid-clair);color:var(--froid)}
  .duo-card.over .tag{background:var(--chaud-clair);color:var(--chaud)}
  .duo-card p{font-size:14px;color:#33454d;margin:0}
  .balance{font-size:15px;color:var(--ink);font-weight:500;margin-top:4px}

  /* étapes numérotées */
  .steps{display:flex;flex-direction:column;gap:14px;margin:6px 0 4px}
  .step{display:flex;gap:14px;align-items:flex-start;border:1px solid var(--line);border-radius:12px;padding:16px 18px;background:#fff}
  .step-num{flex:0 0 auto;width:30px;height:30px;border-radius:50%;background:var(--froid);color:#fff;
    font-family:'Fraunces',serif;font-weight:600;font-size:16px;display:flex;align-items:center;justify-content:center;margin-top:1px}
  .step-body{flex:1;min-width:0}
  .step-body h3{margin:3px 0 7px;font-size:16px}
  .step-body p{margin-bottom:8px}
  .step-body p:last-child,.step-body table:last-child{margin-bottom:0}

  /* formule en évidence */
  .formula{background:#0e767f;color:#fff;border-radius:10px;padding:12px 16px;margin:10px 0;
    font-family:'Fraunces',serif;font-size:16px;text-align:center;line-height:1.4}

  /* FAQ accordéon */
  .faq-item{border:1px solid var(--line);border-radius:10px;margin-bottom:10px;background:#fff}
  .faq-item summary{cursor:pointer;list-style:none;padding:14px 16px;font-weight:600;font-size:15px;color:var(--ink);
    display:flex;justify-content:space-between;align-items:center;gap:12px}
  .faq-item summary::-webkit-details-marker{display:none}
  .faq-item summary::after{content:"+";font-size:22px;line-height:1;color:var(--froid);flex:0 0 auto;font-weight:400}
  .faq-item[open] summary::after{content:"\2212"}
  .faq-item summary:focus-visible{outline:2px solid var(--froid);outline-offset:-2px;border-radius:10px}
  .faq-item .a{padding:0 16px 15px;color:#3c5560;font-size:15px;line-height:1.55}
  @media (prefers-reduced-motion:reduce){*{transition:none!important}}


/* ====== page de référence « par m² » ====== */
.crumb{font-size:13px;color:var(--muted);margin-bottom:18px}
.crumb a{color:var(--froid);text-decoration:none}
.crumb a:hover{text-decoration:underline}
.table-scroll{overflow-x:auto;border:1px solid var(--line);border-radius:var(--radius);background:var(--card);margin:6px 0 10px}
.table-scroll table{width:100%;border-collapse:collapse;font-size:15px;min-width:430px}
.table-scroll thead th{background:#0f7e88;color:#fff;font-weight:600;font-size:14px;padding:12px 10px;text-align:center}
.table-scroll thead th:first-child{text-align:left}
.table-scroll tbody th{text-align:left;font-weight:600;padding:11px 12px;border-bottom:1px solid var(--line);white-space:nowrap}
.table-scroll tbody td{text-align:center;padding:9px 10px;border-bottom:1px solid var(--line);border-left:1px solid var(--line)}
.table-scroll tbody tr:nth-child(even){background:#f6fafa}
.cell-kw{font-weight:600;color:var(--ink);display:block}
.cell-btu{font-size:12px;color:var(--muted);display:block}
.content .table-note{font-size:13px;color:var(--muted);margin-bottom:22px}
.tool-cta{background:var(--froid-clair);border:1px solid #cfe3e5;border-radius:var(--radius);padding:20px 22px;margin:24px 0}
.tool-cta h3{font-family:'Fraunces',serif;font-weight:500;font-size:18px;margin-bottom:6px}
.tool-cta p{font-size:15px;margin-bottom:14px;color:#33454d}
.tool-cta a{display:inline-block;background:var(--froid);color:#fff;text-decoration:none;font-weight:600;font-size:15px;padding:11px 20px;border-radius:10px}
.related{margin-top:30px;padding-top:18px;border-top:1px solid var(--line);font-size:15px}
.related a{color:var(--froid);text-decoration:none;font-weight:600}
.related a:hover{text-decoration:underline}