/* Three primary work areas; course pages use one compact selector. */
body .main-nav,body:is(.cm-open,.studio-open,.advanced-open) .main-nav{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));align-items:stretch;gap:12px;overflow:visible}
body .main-nav a,body:is(.cm-open,.studio-open,.advanced-open) .main-nav a{text-align:center;white-space:normal;font-size:14px;min-height:48px;display:flex;align-items:center;justify-content:center;padding:14px 6px;line-height:1.3}
.notebook-navigation{max-width:1240px;margin:0 auto;padding:18px 36px 0;display:flex;align-items:center;gap:12px}
.notebook-navigation[hidden]{display:none}
.notebook-navigation a{font-size:13px;text-decoration:none;min-height:44px;display:flex;align-items:center;margin-right:auto}
.notebook-navigation a:hover{text-decoration:underline}
.notebook-navigation label{color:var(--muted);font-size:12px}
.notebook-navigation select{max-width:100%;min-width:190px;padding:10px 34px 10px 12px;background:var(--card);color:var(--green);border:1px solid var(--line);border-radius:10px;font-size:14px}
.notebook-home{max-width:1000px;margin:0 auto}
.notebook-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px;margin-top:30px}
.notebook-card{display:flex;flex-direction:column;align-items:flex-start;min-width:0;padding:25px;border:1px solid var(--line);border-radius:var(--radius);background:var(--card);color:var(--ink);text-decoration:none;transition:border-color .15s,background .15s}
.notebook-card:hover{border-color:var(--green);background:#f1f5eb}
.notebook-card .eyebrow{font-size:10px;margin-bottom:14px}
.notebook-card h2{font-size:20px;line-height:1.3}
.notebook-card p{font-size:14px;color:var(--muted);margin:12px 0 22px}
.notebook-card-open{margin-top:auto;font-size:13px;font-weight:650;color:var(--green)}
.notebook-tool-note{margin:25px 0 0;padding:18px 20px;background:var(--light);border-radius:12px;color:var(--muted);font-size:13px}
.notebook-tool-note strong{color:var(--green)}
@media(max-width:900px){.notebook-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:680px){
 body .main-nav,body:is(.cm-open,.studio-open,.advanced-open) .main-nav{gap:6px}
 body .main-nav a,body:is(.cm-open,.studio-open,.advanced-open) .main-nav a{font-size:12px;padding:13px 2px}
 .notebook-navigation{padding:12px 18px 0;gap:8px;flex-wrap:wrap}
 .notebook-navigation a{width:100%;min-height:36px}
 .notebook-navigation label{flex:0 0 auto}
 .notebook-navigation select{flex:1;min-width:0}
 .notebook-grid{gap:12px;margin-top:24px}
 .notebook-card{padding:20px}
 .notebook-card h2{font-size:18px}
}
@media(max-width:460px){.notebook-grid{grid-template-columns:1fr}}
body.studio-focus .main-nav,body.studio-focus .notebook-navigation{display:none}