/* ===== ARTHROSE.CSS ===== */
@import url('https://fonts.googleapis.com/css2?family=Fraunces:ital,opsz,wght@0,9..144,400;0,9..144,600;0,9..144,700;1,9..144,400&family=Mulish:wght@300;400;500;600&family=Space+Mono:wght@400;700&display=swap');

:root {
  --sand:       #faf7f2;
  --warm:       #f5ede0;
  --terra:      #c2410c;
  --terra-med:  #ea580c;
  --terra-pale: #fff7ed;
  --terra-glow: rgba(194,65,12,.07);
  --bone:       #92400e;
  --brown:      #78350f;
  --ochre:      #d97706;
  --text-dark:  #1c0a00;
  --text-body:  #3d1c00;
  --text-mid:   #8a6040;
  --text-light: #c4a882;
  --border:     #e8d5c0;
  --border-t:   rgba(194,65,12,.18);
  --safe:       #059669;
  --blue:       #1d4ed8;
  --font-h:     'Fraunces', serif;
  --font-b:     'Mulish', sans-serif;
  --font-m:     'Space Mono', monospace;
}

*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{font-family:var(--font-b);background:var(--sand);color:var(--text-body);line-height:1.78;overflow-x:hidden}
body::before{content:'';position:fixed;inset:0;background-image:radial-gradient(circle,rgba(194,65,12,.025) 1px,transparent 1px);background-size:22px 22px;pointer-events:none;z-index:0}
::-webkit-scrollbar{width:4px}
::-webkit-scrollbar-track{background:var(--sand)}
::-webkit-scrollbar-thumb{background:var(--terra);border-radius:2px}

#progress-bar{position:fixed;top:0;left:0;height:3px;background:linear-gradient(90deg,var(--brown),var(--terra),var(--ochre));width:0%;z-index:200;transition:width .1s}

nav{position:fixed;top:0;left:0;right:0;z-index:100;height:62px;display:flex;align-items:center;justify-content:space-between;padding:0 3rem;background:rgba(250,247,242,.95);backdrop-filter:blur(20px);border-bottom:1px solid var(--border)}
.nav-logo{display:flex;align-items:center;gap:.8rem;text-decoration:none}
.nav-icon{font-size:1.3rem}
.nav-name{font-family:var(--font-h);font-size:1rem;font-style:italic;color:var(--text-dark)}
.nav-links{display:flex;gap:2rem;list-style:none}
.nav-links a{font-family:var(--font-m);font-size:.7rem;color:var(--text-light);text-decoration:none;letter-spacing:.06em;transition:color .2s}
.nav-links a:hover{color:var(--terra)}
.nav-tag{font-family:var(--font-m);font-size:.67rem;color:var(--terra);background:var(--terra-pale);border:1px solid var(--border-t);padding:.28rem .8rem;border-radius:100px}

.hero{position:relative;z-index:1;min-height:100vh;display:grid;grid-template-columns:1fr 1fr;align-items:center;gap:4rem;padding:8rem 3rem 4rem;overflow:hidden}
.hero-bg{position:absolute;right:0;top:0;bottom:0;width:46%;background:linear-gradient(135deg,var(--warm),#ede0cc);z-index:-1;border-radius:60% 0 0 60%}
.hero-tag{font-family:var(--font-m);font-size:.68rem;color:var(--terra);letter-spacing:.2em;text-transform:uppercase;margin-bottom:1.2rem;display:flex;align-items:center;gap:.7rem}
.hero-tag::before{content:'';width:20px;height:1px;background:var(--terra)}
.hero h1{font-family:var(--font-h);font-size:clamp(3rem,6.5vw,6rem);font-style:italic;line-height:1;color:var(--text-dark);margin-bottom:1.2rem}
.hero h1 .sub{display:block;font-size:.38em;font-style:normal;color:var(--terra);letter-spacing:.04em;font-family:var(--font-b);font-weight:600;margin-top:.3rem}
.hero-desc{font-size:.95rem;color:var(--text-mid);max-width:460px;line-height:1.88;margin-bottom:2.5rem;font-weight:300}
.hero-stats{display:flex;gap:2.5rem;flex-wrap:wrap}
.hs{display:flex;flex-direction:column}
.hs-n{font-family:var(--font-h);font-size:2.2rem;font-style:italic;color:var(--terra);line-height:1}
.hs-l{font-family:var(--font-m);font-size:.63rem;color:var(--text-light);letter-spacing:.1em;text-transform:uppercase;margin-top:.3rem}
.joint-visual{display:flex;align-items:center;justify-content:center;position:relative;z-index:1}

.band{background:var(--brown);padding:3.5rem 3rem;z-index:1;position:relative}
.band-inner{max-width:1160px;margin:0 auto;display:grid;grid-template-columns:repeat(4,1fr);gap:2rem;text-align:center}
.bn{font-family:var(--font-h);font-size:2.8rem;font-style:italic;color:rgba(255,255,255,.85);line-height:1}
.bl{font-family:var(--font-m);font-size:.65rem;color:rgba(255,255,255,.4);letter-spacing:.1em;margin-top:.4rem}

.sec{position:relative;z-index:1;max-width:1160px;margin:0 auto;padding:5rem 3rem}
.shead{display:flex;align-items:baseline;gap:1rem;margin-bottom:3rem;padding-bottom:.8rem;border-bottom:1px solid var(--border)}
.snum{font-family:var(--font-m);font-size:.68rem;color:var(--terra);letter-spacing:.18em;flex-shrink:0}
.stitle{font-family:var(--font-h);font-size:clamp(1.5rem,2.8vw,2.3rem);font-style:italic;color:var(--text-dark)}

.grade-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:1rem}
.grade-card{background:white;border:1px solid var(--border);border-radius:8px;padding:1.8rem;text-align:center;transition:transform .25s,box-shadow .25s}
.grade-card:hover{transform:translateY(-2px);box-shadow:0 6px 20px var(--terra-glow)}
.gk-num{font-family:var(--font-h);font-size:2.5rem;font-style:italic;line-height:1;margin-bottom:.5rem}
.gk-label{font-family:var(--font-m);font-size:.65rem;letter-spacing:.12em;text-transform:uppercase;margin-bottom:.6rem;color:var(--terra)}
.gk-desc{font-size:.82rem;color:var(--text-mid);line-height:1.65}

.table-wrap{overflow-x:auto;border:1px solid var(--border);border-radius:6px}
table{width:100%;border-collapse:collapse;font-size:.87rem}
thead{background:var(--terra-pale)}
th{font-family:var(--font-m);font-size:.65rem;letter-spacing:.12em;text-transform:uppercase;color:var(--brown);padding:.9rem 1.2rem;text-align:left;border-bottom:1px solid var(--border)}
td{padding:.9rem 1.2rem;border-bottom:1px solid rgba(194,65,12,.06);color:var(--text-body);vertical-align:top}
tr:hover td{background:var(--terra-glow)}
tr:last-child td{border-bottom:none}
.tag{font-family:var(--font-m);font-size:.62rem;padding:.18rem .55rem;border-radius:3px;text-transform:uppercase;letter-spacing:.06em}
.tag-t{background:var(--terra-pale);color:var(--brown);border:1px solid var(--border-t)}
.tag-g{background:#d1fae5;color:#065f46;border:1px solid #a7f3d0}
.tag-b{background:#dbeafe;color:#1e40af;border:1px solid #bfdbfe}

.alert-t{background:var(--terra-pale);border:1px solid var(--border-t);border-left:3px solid var(--terra);padding:1.2rem 1.5rem;font-size:.87rem;color:var(--text-body);line-height:1.75;margin-top:1rem}

.fi{opacity:0;transform:translateY(16px);transition:opacity .6s,transform .6s}
.fi.visible{opacity:1;transform:translateY(0)}

footer{background:var(--text-dark);color:rgba(255,255,255,.3);padding:2.5rem 3rem;display:flex;justify-content:space-between;flex-wrap:wrap;gap:1rem;z-index:1;position:relative}
.ft{font-family:var(--font-m);font-size:.7rem}

@media(max-width:900px){
  .hero{grid-template-columns:1fr;padding:7rem 1.2rem 3rem}
  .hero-bg,.joint-visual{display:none}
  .band-inner{grid-template-columns:repeat(2,1fr)}
  nav{padding:0 1.2rem}.nav-links{display:none}
  .sec{padding:3rem 1.2rem}
  footer{padding:2rem 1.2rem}
}