:root{
      --red:#9b0202;
      --text:#111;
      --muted:#444;
      --border:#e6e6e6;
      --bg:#ffffff;
      --card-bg:#ffffff;
      --hover:#f3f4f6;
      --container:1200px;
      --gutter:32px;
      --radius:12px;
      --tcn-header-h:175px;
    }

    h2 {
  color: #9b0202;
}

.tcn-note {
  background: #f7f7f7;
  border-left: 4px solid #9b0202;
  padding: 18px 20px;
  margin: 30px 0;
  font-size: 0.95rem;
  line-height: 1.6;
}

.tcn-note h4 {
  margin-top: 0;
  font-size: 0.9rem;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  color: #9b0202;
}

    * , *::before , *::after { box-sizing: border-box; }
    html { -webkit-text-size-adjust: 100%; }
    body{margin:0;
      padding-top:var(--tcn-header-h);
      font-family:system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
      line-height:1.6;
      color:var(--text);
      background:var(--bg);
  font-size: 16px;
}

    img{ max-width:100%; height:auto; display:block; }
    a{ color:inherit; text-decoration:none; }
    a:hover{ text-decoration:underline; }

    .container{
      width:min(var(--container), 100% - var(--gutter));
      margin-inline:auto;
    }

    .skip-link{
      position:absolute;
      left:-9999px;
      top:8px;
      padding:10px 12px;
      background:#000;
      color:#fff;
      z-index:999;
      border-radius:8px;
    }
    .skip-link:focus{ left:8px; }

    .site-header{
      background:#fff;
      border-bottom:1px solid var(--border);
    }

    .tcn-masthead{ height:var(--tcn-header-h); }


.tcn-article-image {
   display: block;
  width: 75%;
  max-width: 900px;
  height: auto;
  margin: 24px auto;
}

.figcaption {
  text-align: center;
  margin: 24px auto;
}


  :root{
      --red:#9b0202;
      --text:#111;
      --muted:#444;
      --border:#e6e6e6;
      --bg:#ffffff;
      --card-bg:#ffffff;
      --hover:#f3f4f6;
      --container:1200px;
      --gutter:32px;
      --radius:12px;
      --tcn-header-h:175px;
    }

    h2 {
  color: #9b0202;
}

.tcn-note {
  background: #f7f7f7;
  border-left: 4px solid #9b0202;
  padding: 18px 20px;
  margin: 30px 0;
  font-size: 0.95rem;
  line-height: 1.6;
}

.tcn-note h4 {
  margin-top: 0;
  font-size: 0.9rem;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  color: #9b0202;
}

    * , *::before , *::after { box-sizing: border-box; }
    html { -webkit-text-size-adjust: 100%; }
    body{margin:0;
      padding-top:var(--tcn-header-h);
      font-family:system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
      line-height:1.6;
      color:var(--text);
      background:var(--bg);
  font-size: 16px;
}

    img{ max-width:100%; height:auto; display:block; }
    a{ color:inherit; text-decoration:none; }
    a:hover{ text-decoration:underline; }

    .container{
      width:min(var(--container), 100% - var(--gutter));
      margin-inline:auto;
    }

    .skip-link{
      position:absolute;
      left:-9999px;
      top:8px;
      padding:10px 12px;
      background:#000;
      color:#fff;
      z-index:999;
      border-radius:8px;
    }
    .skip-link:focus{ left:8px; }

    .site-header{
      background:#fff;
      border-bottom:1px solid var(--border);
    }

    .tcn-masthead{ height:var(--tcn-header-h); }

    main{ padding:38px 0 40px; }

     .page{ padding: 28px 0 44px; }

    .article-wrap{
      max-width: 760px;
      margin: 0 auto;
    }

    .kicker{
      margin: 0 0 8px;
      font-size: 12px;
      letter-spacing: 0.6px;
      text-transform: uppercase;
      color: #555;
    }

    .article-title{
      margin:0 0 10px;
      font-size: 34px;
      line-height: 1.15;
      letter-spacing: -0.2px;
    }

    .article-meta{
      margin: 0 0 18px;
      color: var(--muted);
      font-size: 14px;
    }

    .lead{
      margin: 0 0 18px;
      color: #222;
      font-size: 17px;
    }

    .article-body p{
      margin: 0 0 18px;
      font-size: 16px;
    }

    .article-body h2{
      margin: 28px 0 12px;
      font-size: 22px;
      line-height: 1.25;
    }

    .article-body h3{
      margin: 22px 0 10px;
      font-size: 18px;
      line-height: 1.25;
    }

    .callout{
      border-left: 4px solid var(--red);
      padding: 10px 14px;
      background: #fafafa;
      margin: 18px 0;
      border-radius: 10px;
    }

    .embed{
      max-width: 900px;
      margin: 26px auto;
      border: 1px solid var(--border);
      border-radius: var(--radius);
      overflow: hidden;
      background: #fff;
    }
    .embed iframe{
      width:100%;
      height:500px;
      border:0;
      display:block;
    }
    .embed-caption{
      margin:0;
      padding:10px 12px;
      border-top:1px solid var(--border);
      font-size: 13px;
      color: var(--muted);
      text-align: center;
    }

    .hero-band{
      background:var(--red);
      color:#fff;
      padding:22px 0;
      margin-top: 34px;
    }
    .hero-row{
      display:flex;
      align-items:baseline;
      justify-content:space-between;
      gap:16px;
      flex-wrap:wrap;
    }
    .hero-title{
      margin:0;
      font-size:22px;
      color: #ffffff;
      line-height:1.2;
    }

    .cards-grid{
      display:grid;
      grid-template-columns: repeat(4, 1fr);
      gap:22px;
      margin-top: 18px;
    }

    .card{
      border:1px solid var(--border);
      border-radius:var(--radius);
      overflow:hidden;
      background:var(--card-bg);
    }

    .card-link{
      display:block;
      height:100%;
    }
    .card-link:focus-visible{
      outline:3px solid #000;
      outline-offset:2px;
      border-radius:var(--radius);
    }

    .card-media{
      margin:0;
      background:#f3f4f6;
      aspect-ratio:16/9;
      overflow:hidden;
    }
    .card-media img{
      width:100%;
      height:100%;
      object-fit:cover;
    }

    .card-body{
      padding:14px 14px 16px;
    }

    .card-title{
      margin:0 0 8px;
      font-size:16px;
      line-height:1.25;
    }

    .card-excerpt{
      margin:0;
      color:#333;
      font-size:14px;
    }

    .site-footer{
      border-top:1px solid var(--border);
      padding:18px 0;
      background:#fff;
      margin-top: 34px;
    }
    .footer-inner{
      display:flex;
      align-items:center;
      justify-content:space-between;
      gap:16px;
      flex-wrap:wrap;
    }
    .footer-small{
      margin:0;
      color:var(--muted);
      font-size:14px;
    }
    .footer-nav{
      display:flex;
      gap:14px;
      flex-wrap:wrap;
    }
    .footer-nav a:hover{ text-decoration: underline; }

    @media (max-width: 980px){
      .cards-grid{ grid-template-columns: repeat(2, 1fr); }
      .article-title{ font-size: 30px; }
    }
    @media (max-width: 640px){
      .cards-grid{ grid-template-columns: 1fr; }
      .article-title{ font-size: 26px; }
      .embed iframe{ height: 320px; }
    }
  

    .article-body{ line-height: 1.65; }

    /* Series module */
    .series-module{
      margin: 18px 0 22px;
      padding: 14px 16px;
      border: 1px solid var(--border);
      border-radius: 12px;
      background: #fbfbfb;
      font-size: 14px;
      color: var(--muted);
    }
    .series-module strong{ color: var(--text); }
    .series-module a{
      color: var(--red);
      text-decoration: none;
      font-weight: 600;
    }
    .series-module a:hover{ text-decoration: underline; }

    /* Pull quotes */
    .pullquote{
      border-left: 5px solid var(--red);
      padding: 14px 16px;
      background: #fff7f7;
      margin: 24px 0;
      border-radius: 14px;
      font-size: 19px;
      line-height: 1.45;
      color: #1a1a1a;
    }
    .pullquote:before{
      
      font-size: 44px;
      line-height: 0.9;
      color: var(--red);
      display: block;
      margin-bottom: 6px;
    }

    .section-divider{
      border: 0;
      border-top: 1px solid var(--border);
      margin: 28px 0;
    }

    .author-box{
      padding: 14px 16px;
      border: 1px solid var(--border);
      border-radius: 12px;
      background: #fbfbfb;
      font-size: 14px;
      color: var(--muted);
    }
    .author-box strong{ color: var(--text); }


    /* Contents (TOC) */
    .toc{
      margin: 18px 0 26px;
      padding: 14px 16px;
      border: 1px solid var(--border);
      border-radius: 12px;
      background: #FAF9F6;
    }
    .toc-title{
      font-weight: 700;
      margin: 0 0 10px;
      color: var(--text);
      letter-spacing: 0.2px;
    }
    .toc ul{
      list-style: none;
      padding: 0;
      margin: 0;
      font-size: small;
      display: grid;
      grid-template-columns: 1fr;
      gap: 4px;
    }
    @media(min-width: 820px){
      .toc ul{ grid-template-columns: 1fr 1fr; }
    }
    .toc a{
      text-decoration: none;
      color: var(--muted);
    }
    .toc a:hover{
      color: var(--text);
      text-decoration: underline;
      text-underline-offset: 3px;
    }

    /* Series pills */
    .series-nav{
      margin-top: 10px;
      display: flex;
      flex-wrap: wrap;
      gap: 8px;
    }
    .series-pill{
      display: inline-block;
      padding: 6px 10px;
      border-radius: 999px;
      border: 1px solid var(--border);
      font-size: 13px;
      line-height: 1;
      color: var(--muted);
      text-decoration: none;
      background: #ffffff;
    }
    .series-pill.active{
      border-color: var(--red);
      color: var(--red);
      font-weight: 700;
      background: #fff7f7;
    }

    /* Audio version (Web Speech API) */
    .tcn-audio-tools{
      display:flex;
      align-items:center;
      gap:10px;
      flex-wrap:wrap;
      padding:12px 14px;
      border:1px solid var(--border);
      border-radius:12px;
      background:#fbfbfb;
      margin: 12px 0 14px;
    }
    .tcn-audio-tools button{
      appearance:none;
      border:1px solid var(--border);
      background:#ffffff;
      color:var(--text);
      padding:8px 12px;
      border-radius:10px;
      font-size:14px;
      cursor:pointer;
    }
    .tcn-audio-tools button:hover{ background: var(--hover); }
    .tcn-audio-tools button:disabled{
      opacity:0.55;
      cursor:not-allowed;
    }
    
    .tcn-audio-tools select{
      appearance:none;
      border:1px solid var(--border);
      background:#ffffff;
      color:var(--text);
      padding:7px 10px;
      border-radius:10px;
      font-size:14px;
      cursor:pointer;
      max-width: 240px;
    }
    .tcn-audio-tools select:hover{ background: var(--hover); }
.tcn-audio-tools .tcn-audio-label{
      display:flex;
      align-items:center;
      gap:8px;
      font-size:13px;
      color:var(--muted);
    }
    .tcn-audio-tools input[type="range"]{ width:140px; }
    .tcn-audio-tools .tcn-audio-status{
      font-size:13px;
      color:var(--muted);
      margin-left:auto;
      white-space:nowrap;
    }


    /* Supplement snapshot callout */
    .callout--snapshot{ padding: 14px 16px; }
    .callout-title{
      margin: 0 0 10px;
      font-size: 12px;
      letter-spacing: 0.6px;
      text-transform: uppercase;
      color: var(--red);
    }
    .callout-subtitle{ margin: 10px 0 6px; font-size: 14px; }
    .callout-dl{
      margin:0;
      display:grid;
      gap: 8px;
    }
    .callout-dl > div{
      display:grid;
      grid-template-columns: 150px 1fr;
      gap: 10px;
    }
    .callout-dl dt{ font-weight: 700; color: #333; }
    .callout-dl dd{ margin:0; color:#222; }
    .callout-list{ margin: 0; padding-left: 18px; }


    main{ padding:28px 0 40px; }

    .article-wrap{
      max-width: 760px;
      margin: 0 auto;
    }

    .kicker{
      margin: 0 0 8px;
      font-size: 12px;
      letter-spacing: 0.6px;
      text-transform: uppercase;
      color: #555;
    }

    .article-title{
      margin:0 0 10px;
      font-size: 34px;
      line-height: 1.15;
      letter-spacing: -0.2px;
    }

    .article-meta{
      margin: 0 0 18px;
      color: var(--muted);
      font-size: 14px;
    }

    .lead{
      margin: 0 0 18px;
      color: #222;
      font-size: 17px;
    }

    .article-body p{
      margin: 0 0 18px;
      font-size: 16px;
    }

    .article-body h2{
      margin: 28px 0 12px;
      font-size: 22px;
      line-height: 1.25;
    }

    .article-body h3{
      margin: 22px 0 10px;
      font-size: 18px;
      line-height: 1.25;
    }

    .callout{
      border-left: 4px solid var(--red);
      padding: 10px 14px;
      background: #fafafa;
      margin: 18px 0;
      border-radius: 10px;
    }

    .embed{
      max-width: 900px;
      margin: 26px auto;
      border: 1px solid var(--border);
      border-radius: var(--radius);
      overflow: hidden;
      background: #fff;
    }
    .embed iframe{
      width:100%;
      height:500px;
      border:0;
      display:block;
    }
    .embed-caption{
      margin:0;
      padding:10px 12px;
      border-top:1px solid var(--border);
      font-size: 13px;
      color: var(--muted);
      text-align: center;
    }

    .hero-band{
      background:var(--red);
      color:#fff;
      padding:22px 0;
      margin-top: 34px;
    }
    .hero-row{
      display:flex;
      align-items:baseline;
      justify-content:space-between;
      gap:16px;
      flex-wrap:wrap;
    }
    .hero-title{
      margin:0;
      font-size:22px;
      color: #ffffff;
      line-height:1.2;
    }

    .cards-grid{
      display:grid;
      grid-template-columns: repeat(4, 1fr);
      gap:22px;
      margin-top: 18px;
    }

    .card{
      border:1px solid var(--border);
      border-radius:var(--radius);
      overflow:hidden;
      background:var(--card-bg);
    }

    .card-link{
      display:block;
      height:100%;
    }
    .card-link:focus-visible{
      outline:3px solid #000;
      outline-offset:2px;
      border-radius:var(--radius);
    }

    .card-media{
      margin:0;
      background:#f3f4f6;
      aspect-ratio:16/9;
      overflow:hidden;
    }
    .card-media img{
      width:100%;
      height:100%;
      object-fit:cover;
    }

    .card-body{
      padding:14px 14px 16px;
    }

    .card-title{
      margin:0 0 8px;
      font-size:16px;
      line-height:1.25;
    }

    .card-excerpt{
      margin:0;
      color:#333;
      font-size:14px;
    }

    .site-footer{
      border-top:1px solid var(--border);
      padding:18px 0;
      background:#fff;
      margin-top: 34px;
    }
    .footer-inner{
      display:flex;
      align-items:center;
      justify-content:space-between;
      gap:16px;
      flex-wrap:wrap;
    }
    .footer-small{
      margin:0;
      color:var(--muted);
      font-size:14px;
    }
    .footer-nav{
      display:flex;
      gap:14px;
      flex-wrap:wrap;
    }
    .footer-nav a:hover{ text-decoration: underline; }

    @media (max-width: 980px){
      .cards-grid{ grid-template-columns: repeat(2, 1fr); }
      .article-title{ font-size: 30px; }
    }
    @media (max-width: 640px){
      .cards-grid{ grid-template-columns: 1fr; }
      .article-title{ font-size: 26px; }
      .embed iframe{ height: 320px; }
    }
  

    .article-body{ line-height: 1.65; }

    /* Series module */
    .series-module{
      margin: 18px 0 22px;
      padding: 14px 16px;
      border: 1px solid var(--border);
      border-radius: 12px;
      background: #fbfbfb;
      font-size: 14px;
      color: var(--muted);
    }
    .series-module strong{ color: var(--text); }
    .series-module a{
      color: var(--red);
      text-decoration: none;
      font-weight: 600;
    }
    .series-module a:hover{ text-decoration: underline; }

    /* Pull quotes */
    .pullquote{
      border-left: 5px solid var(--red);
      padding: 14px 16px;
      background: #fff7f7;
      margin: 24px 0;
      border-radius: 14px;
      font-size: 19px;
      line-height: 1.45;
      color: #1a1a1a;
    }
    .pullquote:before{
      
      font-size: 44px;
      line-height: 0.9;
      color: var(--red);
      display: block;
      margin-bottom: 6px;
    }

    .section-divider{
      border: 0;
      border-top: 1px solid var(--border);
      margin: 28px 0;
    }

    .author-box{
      padding: 14px 16px;
      border: 1px solid var(--border);
      border-radius: 12px;
      background: #fbfbfb;
      font-size: 14px;
      color: var(--muted);
    }
    .author-box strong{ color: var(--text); }


    /* Contents (TOC) */
    .toc{
      margin: 18px 0 26px;
      padding: 14px 16px;
      border: 1px solid var(--border);
      border-radius: 12px;
      background: #FAF9F6;
    }
    .toc-title{
      font-weight: 700;
      margin: 0 0 10px;
      color: var(--text);
      letter-spacing: 0.2px;
    }
    .toc ul{
      list-style: none;
      padding: 0;
      margin: 0;
      font-size: small;
      display: grid;
      grid-template-columns: 1fr;
      gap: 4px;
    }
    @media(min-width: 820px){
      .toc ul{ grid-template-columns: 1fr 1fr; }
    }
    .toc a{
      text-decoration: none;
      color: var(--muted);
    }
    .toc a:hover{
      color: var(--text);
      text-decoration: underline;
      text-underline-offset: 3px;
    }

    /* Series pills */
    .series-nav{
      margin-top: 10px;
      display: flex;
      flex-wrap: wrap;
      gap: 8px;
    }
    .series-pill{
      display: inline-block;
      padding: 6px 10px;
      border-radius: 999px;
      border: 1px solid var(--border);
      font-size: 13px;
      line-height: 1;
      color: var(--muted);
      text-decoration: none;
      background: #ffffff;
    }
    .series-pill.active{
      border-color: var(--red);
      color: var(--red);
      font-weight: 700;
      background: #fff7f7;
    }

    /* Audio version (Web Speech API) */
    .tcn-audio-tools{
      display:flex;
      align-items:center;
      gap:10px;
      flex-wrap:wrap;
      padding:12px 14px;
      border:1px solid var(--border);
      border-radius:12px;
      background:#fbfbfb;
      margin: 12px 0 14px;
    }
    .tcn-audio-tools button{
      appearance:none;
      border:1px solid var(--border);
      background:#ffffff;
      color:var(--text);
      padding:8px 12px;
      border-radius:10px;
      font-size:14px;
      cursor:pointer;
    }
    .tcn-audio-tools button:hover{ background: var(--hover); }
    .tcn-audio-tools button:disabled{
      opacity:0.55;
      cursor:not-allowed;
    }
    
    .tcn-audio-tools select{
      appearance:none;
      border:1px solid var(--border);
      background:#ffffff;
      color:var(--text);
      padding:7px 10px;
      border-radius:10px;
      font-size:14px;
      cursor:pointer;
      max-width: 240px;
    }
    .tcn-audio-tools select:hover{ background: var(--hover); }
.tcn-audio-tools .tcn-audio-label{
      display:flex;
      align-items:center;
      gap:8px;
      font-size:13px;
      color:var(--muted);
    }
    .tcn-audio-tools input[type="range"]{ width:140px; }
    .tcn-audio-tools .tcn-audio-status{
      font-size:13px;
      color:var(--muted);
      margin-left:auto;
      white-space:nowrap;
    }


    /* Supplement snapshot callout */
    .callout--snapshot{ padding: 14px 16px; }
    .callout-title{
      margin: 0 0 10px;
      font-size: 12px;
      letter-spacing: 0.6px;
      text-transform: uppercase;
      color: var(--red);
    }
    .callout-subtitle{ margin: 10px 0 6px; font-size: 14px; }
    .callout-dl{
      margin:0;
      display:grid;
      gap: 8px;
    }
    .callout-dl > div{
      display:grid;
      grid-template-columns: 150px 1fr;
      gap: 10px;
    }
    .callout-dl dt{ font-weight: 700; color: #333; }
    .callout-dl dd{ margin:0; color:#222; }
    .callout-list{ margin: 0; padding-left: 18px; }


    /* Comparison box: hip vs knee */
    .compare-box{
      border:1px solid var(--border);
      border-radius: 14px;
      background: #fbfbfb;
      padding: 14px 16px;
      margin: 22px 0;
    }
    .compare-title{
      margin:0 0 10px;
      font-size: 12px;
      letter-spacing: 0.6px;
      text-transform: uppercase;
      color: var(--red);
      font-weight: 700;
    }
    .compare-grid{
      display:grid;
      grid-template-columns: 1fr;
      gap: 12px;
    }
    @media(min-width: 760px){
      .compare-grid{ grid-template-columns: 1fr 1fr; }
    }
    .compare-card{
      border: 1px solid var(--border);
      border-radius: 12px;
      background:#ffffff;
      padding: 12px 12px;
    }
    .compare-card h4{
      margin:0 0 8px;
      font-size: 14px;
      color: var(--text);
    }
    .compare-card ul{
      margin:0;
      padding-left: 18px;
      color:#222;
      font-size: 14px;
    }
    .compare-foot{
      margin: 10px 0 0;
      color: var(--muted);
      font-size: 13px;
    }