:root{--bg: #fafafa;--surface: #ffffff;--text: #1a1a1a;--muted: #6b6b6b;--border: #e5e5e5;--accent: #1a1a1a;--accent-contrast: #ffffff;--danger: #b42318;--success: #067647;--warning: #b54708;--radius: 6px;--font: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);font:15px/1.5 var(--font)}a{color:var(--text)}h1{font-size:1.5rem;font-weight:600;margin:0 0 1rem}h2{font-size:1.15rem;font-weight:600;margin:0 0 .5rem}.container{max-width:1080px;margin:0 auto;padding:0 1rem}.app{min-height:100vh;display:flex;flex-direction:column}.main{flex:1;width:100%;padding-top:2rem;padding-bottom:3rem}.header{background:var(--surface);border-bottom:1px solid var(--border)}.header__inner{display:flex;align-items:center;gap:2rem;height:56px}.brand{font-weight:700;letter-spacing:-.01em}.nav{display:flex;gap:1.25rem;flex:1}.nav a{text-decoration:none;color:var(--muted);padding:.25rem 0;border-bottom:2px solid transparent}.nav a.active{color:var(--text);border-bottom-color:var(--text)}.header__user{display:flex;align-items:center;gap:.75rem;margin-left:auto;font-size:.9rem}.footer{border-top:1px solid var(--border);font-size:.8rem;color:var(--muted)}.footer__inner{display:flex;justify-content:space-between;align-items:center;height:48px}.btn{display:inline-flex;align-items:center;justify-content:center;height:36px;padding:0 1rem;border:1px solid var(--accent);border-radius:var(--radius);background:var(--accent);color:var(--accent-contrast);font:inherit;font-size:.9rem;cursor:pointer}.btn:hover:not(:disabled){opacity:.85}.btn:disabled{opacity:.35;cursor:not-allowed}.btn--ghost{background:transparent;color:var(--text);border-color:var(--border)}.btn--link{background:none;border:none;height:auto;padding:0;color:var(--muted);text-decoration:underline}.btn--small{height:30px;padding:0 .75rem;font-size:.85rem}.btn--block{width:100%}.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:1.5rem}.auth{max-width:400px;margin:0 auto;display:grid;gap:1rem}.form{display:grid;gap:.5rem}.form label{display:grid;gap:.3rem;font-size:.875rem;color:var(--muted)}.form .btn{margin-top:.75rem}input[type=text],input[type=password],input[type=email],input[type=search],select{height:38px;padding:0 .75rem;border:1px solid var(--border);border-radius:var(--radius);background:var(--surface);color:var(--text);font:inherit}input:focus,select:focus,button:focus-visible{outline:2px solid var(--accent);outline-offset:1px}.checkbox{display:flex!important;align-items:center;gap:.5rem;grid-template-columns:none}.field-error{color:var(--danger);font-size:.8rem;margin-top:-.2rem}.form-error{color:var(--danger);font-size:.875rem;margin:.5rem 0}.muted{color:var(--muted);font-size:.875rem}.center{text-align:center}.demo summary{cursor:pointer;font-size:.875rem;color:var(--muted)}.demo table{margin-top:.75rem}.page-head{display:flex;justify-content:space-between;align-items:baseline;gap:1rem;flex-wrap:wrap}.filters{display:flex;gap:.75rem;flex-wrap:wrap;align-items:center;margin-bottom:1.25rem}.filters input[type=search]{flex:1;min-width:220px}.radios{display:flex;gap:1rem;border:none;margin:0;padding:0;font-size:.875rem}.radios label{display:flex;align-items:center;gap:.3rem;cursor:pointer}.table{width:100%;border-collapse:collapse;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);font-size:.9rem}.table th,.table td{text-align:left;padding:.65rem .75rem;border-bottom:1px solid var(--border);vertical-align:middle}.table th{font-weight:500;color:var(--muted);font-size:.8rem;text-transform:uppercase;letter-spacing:.03em}.table tbody tr:last-child td{border-bottom:none}.table tbody tr:hover{background:#f5f5f5}.table--compact th,.table--compact td{padding:.35rem .5rem;font-size:.8rem}.sort-btn{background:none;border:none;padding:0;font:inherit;color:inherit;text-transform:inherit;letter-spacing:inherit;cursor:pointer;display:inline-flex;gap:.3rem}.sort-icon{font-size:.65rem;min-width:.65rem}.actions{display:flex;gap:.5rem;align-items:center;white-space:nowrap}.actions a{font-size:.85rem}.pagination{display:flex;justify-content:center;align-items:center;gap:1rem;margin-top:1.25rem;font-size:.875rem}.loading,.empty{padding:3rem 0;text-align:center;color:var(--muted)}.back-link{display:inline-block;margin-bottom:1rem;font-size:.875rem;color:var(--muted);text-decoration:none}.book-detail{max-width:560px}.book-detail__title{margin-bottom:.25rem}.book-detail__author{color:var(--muted);margin:0 0 1.25rem}.book-detail__meta{display:grid;grid-template-columns:120px 1fr;gap:.4rem 1rem;margin:0 0 1.25rem;font-size:.9rem}.book-detail__meta dt{color:var(--muted)}.book-detail__meta dd{margin:0}.book-detail__status{font-size:.875rem}.book-detail__status.is-available{color:var(--success)}.book-detail__status.is-unavailable{color:var(--danger)}.segmented{display:inline-flex;border:1px solid var(--border);border-radius:var(--radius);overflow:hidden;margin-bottom:1.25rem}.segmented button{background:var(--surface);border:none;border-right:1px solid var(--border);padding:.45rem 1rem;font:inherit;font-size:.875rem;color:var(--muted);cursor:pointer}.segmented button:last-child{border-right:none}.segmented button.is-active{background:var(--accent);color:var(--accent-contrast)}.badge{display:inline-block;padding:.1rem .5rem;border-radius:999px;font-size:.75rem;border:1px solid currentColor}.badge--activo{color:var(--success)}.badge--vencido{color:var(--danger)}.badge--devuelto{color:var(--muted)}.modal-backdrop{position:fixed;inset:0;background:#0000004d;display:grid;place-items:center;padding:1rem;z-index:10}.modal{background:var(--surface);border-radius:var(--radius);padding:1.5rem;width:100%;max-width:400px;display:grid;gap:.5rem}.modal label{font-size:.875rem;color:var(--muted)}.modal__book{margin:0 0 .5rem;font-weight:500}.modal__actions{display:flex;justify-content:flex-end;gap:.5rem;margin-top:.75rem}.toast{position:fixed;bottom:1.5rem;right:1.5rem;padding:.75rem 1rem;border-radius:var(--radius);background:var(--accent);color:var(--accent-contrast);font-size:.875rem;z-index:20}.toast--error{background:var(--danger)}.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}@media(max-width:720px){.header__inner{gap:1rem;height:auto;padding:.75rem 1rem;flex-wrap:wrap}.table{display:block;overflow-x:auto}}