.lesson-body{line-height:1.8}.lesson-body .math{display:inline-block;font-size:1.15em;vertical-align:middle}.breadcrumb{color:#777}.admin-wrap{max-width:1200px;margin:2rem auto;padding:0 1.25rem}.admin-nav{display:flex;gap:1rem;flex-wrap:wrap;margin:1.2rem 0}.admin-nav a{border-bottom:0}.admin-table{width:100%}.admin-actions{display:flex;gap:.5rem;flex-wrap:wrap}.admin-actions form{margin:0}.editor{min-height:360px;border:1px solid #bbb;padding:1rem;background:#fff;border-radius:.35rem;overflow:auto}.editor:focus{outline:2px solid #f56a6a}.editor-toolbar{display:flex;gap:.3rem;flex-wrap:wrap;margin:.5rem 0}.editor-toolbar button{padding:0 .8rem;height:2.5rem;line-height:2.5rem}.flash{background:#f5f6f7;padding:1rem;border-left:3px solid #f56a6a}.field-grid{display:grid;grid-template-columns:1fr 1fr;gap:1rem}@media(max-width:700px){.field-grid{grid-template-columns:1fr}} 
.lesson-body .math-block{display:block;text-align:center;margin:1.25rem 0;font-size:1.2em}

/* Nested accordion: hide all levels unless their own opener is active. */
#menu li > .opener + ul { display: none; }
#menu li > .opener.active + ul { display: block; }