/* Extensión de la identidad de Ruta: operar y leer, con una acción principal. */
.study-nav { display: grid; grid-template-columns: 1fr 1fr; gap: 4px; padding: 0 16px 16px; border-bottom: 1px solid #293b4b; }
.study-nav a { color: #a6bacb; padding: 10px 8px; text-decoration: none; font-size: 13px; border-radius: 6px; }
.study-nav a:hover, .study-nav a:focus-visible { color: #5eead4; background: #17232e; }
.study-nav a[aria-current="page"] { color: #5eead4; background: #17232e; }
.study-page > h2:focus { outline: none; }
.study-page { max-width: 1060px; margin: auto; padding: 24px 0 50px; }
.study-page > h2 { font-size: clamp(25px, 4vw, 36px); line-height: 1.2; margin: 0 0 16px; }
.study-intro { max-width: 70ch; color: #a6bacb; margin: 0 0 30px; line-height: 1.65; }
.study-lead { padding: 26px 0; border-top: 1px solid #293b4b; border-bottom: 1px solid #293b4b; margin-bottom: 20px; }
.study-lead h3 { font-size: 24px; margin: 0 0 10px; }
.study-lead p { margin: 0 0 18px; }
.study-row { display: flex; align-items: center; justify-content: space-between; gap: 24px; padding: 22px 0; border-bottom: 1px solid #293b4b; }
.study-row h3 { font-size: 17px; margin: 0 0 6px; }
.study-row p { color: #a6bacb; margin: 0; line-height: 1.6; max-width: 70ch; overflow-wrap: anywhere; }
.study-row .btn { flex-shrink: 0; }
.study-page > section > h3 { margin-top: 32px; }
.study-tools { display: flex; gap: 12px; flex-wrap: wrap; margin: 20px 0; }
.study-page input:not([type=checkbox]), .study-page textarea, .study-page select, .login-panel input { border: 1px solid #3b5265; background: #0a0e13; color: #e7eef5; padding: 12px; border-radius: 6px; font: inherit; max-width: 100%; box-sizing: border-box; }
.study-tools input { flex: 1; min-width: 180px; }
.study-page label, .notebook-form { display: grid; gap: 10px; margin: 16px 0; }
.notebook-form { max-width: 780px; }
.study-page textarea { width: 100%; min-height: 200px; resize: vertical; }
.study-page pre { white-space: pre-wrap; overflow-wrap: anywhere; padding: 18px; background: #111922; max-width: 100%; overflow: auto; }
.solution-explanation { padding: 0 22px 18px; font-size: 14px; }
.solution-explanation summary { cursor: pointer; color: #a6bacb; padding: 12px 0; }
.solution-explanation p { line-height: 1.7; }
.login-panel { max-width: 430px; margin: 8vh auto; display: grid; gap: 20px; }
.login-panel label { display: grid; gap: 10px; }
#saveStatus { font-size: 12px; color: #a6bacb; line-height: 1.6; padding-top: 8px; }
@media(max-width:600px) { .study-row { align-items: flex-start; flex-direction: column; gap: 14px; } .study-page { padding-top: 12px; } .study-page input, .study-page textarea, .study-page select, .login-panel input { font-size:16px; } }

@media(max-width:600px) { .topbar #btnCheat { display:none; } .topbar-actions { flex-wrap:nowrap; } }