:root{--ink:#182b41;--muted:#596b7e;--line:#dce4ed;--nav:#122338;--blue:#315cdb;--teal:#146d61;--bg:#f3f6fa;--white:#fff;--radius:14px;font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:var(--ink);font-size:16px;line-height:1.55}*{box-sizing:border-box}body{margin:0;background:var(--bg)}a{color:var(--blue);text-decoration:none}a:hover{text-decoration:underline}button,input,select,textarea{font:inherit}button,a,input,select,textarea{touch-action:manipulation}button{cursor:pointer}button:disabled{cursor:wait;opacity:.6}a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible{outline:3px solid #327af4;outline-offset:3px}.skip{position:fixed;top:-100px;left:20px;z-index:50;background:white;padding:12px}.skip:focus{top:10px}.sidebar{position:fixed;inset:0 auto 0 0;width:242px;background:var(--nav);color:#dae4ee;padding:32px 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a{flex-shrink:0}.page-heading{flex-wrap:wrap}h1{font-size:30px}footer{padding:20px;flex-direction:column}.card{padding:20px}.resources{grid-template-columns:1fr}}@media(max-width:450px){.stats{grid-template-columns:1fr}.stat{display:flex}.stat strong{margin-top:0}.stat>div{display:flex;align-items:center;justify-content:space-between;width:100%}.stat-icon{display:none}.tool-grid,.all-tools,.calc-grid{grid-template-columns:1fr}.header-actions{gap:8px}.breadcrumb{font-size:12px}.record{flex-direction:column}.formula{font-size:23px}}@media print{.sidebar,.topbar,footer,.actions,.source,.lesson-menu,.notice{display:none}.shell{margin:0}main{padding:0}.card{border:0;padding:0}.lesson-layout{display:block}body{background:white}.print-only{display:block}h1{font-size:26px}}
[hidden]{display:none!important}
.brand-sub,.sidebar-foot .small,.intro .eyebrow{font-size:12px}.brand-sub{letter-spacing:1px}.record-actions button{font-size:14px}

/* Private study image gallery */
.sidebar{overflow-y:auto}.sidebar-foot{flex-shrink:0}.image-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px;margin:22px 0}.image-card{border:1px solid var(--line);border-radius:12px;overflow:hidden;min-width:0}.image-preview{display:grid;place-items:center;width:100%;height:200px;background:#edf2f8;border:0;color:var(--muted);padding:10px}.image-preview img{max-width:100%;max-height:180px;object-fit:contain}.image-details{padding:18px}.image-details h3,.image-details p{overflow-wrap:anywhere}.image-details p{white-space:pre-wrap;color:var(--muted);font-size:14px}.image-details .actions{margin-top:14px}.image-details .button{font-size:13px;padding:7px 10px}.image-full{display:block;max-width:100%;height:auto;margin:16px auto}.image-placeholder{font-size:14px}#gallery-status{color:var(--muted);font-size:14px}#image-upload-status{margin-top:15px;overflow-wrap:anywhere}@media(max-width:1150px){.image-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}@media(max-width:600px){.image-grid{grid-template-columns:1fr}.image-preview{height:240px}.image-preview img{max-height:220px}}