:root{--ink:#14213d;--muted:#5c677d;--bg:#f6f7fb;--card:#fff;--line:#dde1ea;--acc:#1f6feb;--ok:#1a7f37;--okbg:#e6f6ea;--warn:#b35900;--warnbg:#fff3e0;--bad:#b42318;--badbg:#fdecea;--esp:#8250df;--mat:#1f6feb}
*{box-sizing:border-box}html{-webkit-text-size-adjust:100%}
body{margin:0;font-family:system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;background:var(--bg);color:var(--ink);font-size:17px;line-height:1.5}
a{color:var(--acc)}header{background:var(--ink);color:#fff;padding:10px 16px;display:flex;justify-content:space-between;align-items:center;position:sticky;top:0;z-index:5}
header a{color:#fff;text-decoration:none}header .brand{font-weight:800;letter-spacing:.3px}header .who{font-size:14px;opacity:.85}
main{max-width:760px;margin:0 auto;padding:16px}
.card{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:16px;margin:0 0 14px}
h1{font-size:24px;margin:4px 0 12px}h2{font-size:20px;margin:0 0 10px}h3{font-size:17px;margin:14px 0 6px}
.btn{display:inline-block;border:0;border-radius:12px;padding:12px 18px;font-size:17px;font-weight:700;background:var(--acc);color:#fff;cursor:pointer;text-decoration:none;text-align:center}
.btn.block{display:block;width:100%;margin:8px 0}.btn.sec{background:#e8eefc;color:var(--acc)}.btn.ghost{background:transparent;color:var(--muted);border:1px solid var(--line)}
.btn.small{padding:8px 12px;font-size:15px}.row{display:flex;gap:8px;flex-wrap:wrap}.row>*{flex:1}
.muted{color:var(--muted);font-size:15px}.pill{display:inline-block;border-radius:999px;padding:2px 10px;font-size:13px;font-weight:700;background:#eef1f6;color:var(--muted)}
.bar{height:10px;border-radius:6px;background:#e7eaf1;overflow:hidden}.bar>i{display:block;height:100%;background:var(--acc)}
.topic{margin:10px 0}.topic .lbl{display:flex;justify-content:space-between;font-size:15px}
.txt{background:#fbfaf6;border-left:5px solid var(--esp);border-radius:8px;padding:12px 14px;font-family:Georgia,"Times New Roman",serif;font-size:17px;line-height:1.6;margin:0 0 12px}
.gl{font-size:14px;color:var(--muted);font-family:system-ui,sans-serif;margin-top:6px}
.stem{margin:0 0 12px}.fig img{display:block;max-width:100%;height:auto;margin:6px auto 12px}
table.dt{border-collapse:collapse;margin:6px 0 12px;font-size:15px}table.dt th,table.dt td{border-bottom:1px solid var(--line);padding:5px 10px;text-align:left}table.dt th{border-bottom:2px solid var(--ink)}
.opts{display:flex;flex-direction:column;gap:8px}
.opt{display:flex;gap:10px;align-items:flex-start;width:100%;text-align:left;background:#fff;border:2px solid var(--line);border-radius:12px;padding:12px 14px;font-size:17px;color:var(--ink);cursor:pointer}
.opt b.l{min-width:22px}.opt:hover{border-color:var(--acc)}.opt[disabled]{cursor:default;opacity:.55}.opt.picked{border-color:var(--acc);background:#eef4ff;opacity:1}
.opt.right{border-color:var(--ok);background:var(--okbg);opacity:1}.opt.wrong{border-color:var(--bad);background:var(--badbg);opacity:1}
.fb{border-radius:12px;padding:12px 14px;margin:14px 0}.fb.ok{background:var(--okbg);border:1px solid #9bd3a8}.fb.warn{background:var(--warnbg);border:1px solid #f0c48a}.fb.bad{background:var(--badbg);border:1px solid #f1a9a2}
.sol{background:#f4f6fb;border-radius:10px;padding:10px 12px;font-size:16px}
.top{display:flex;justify-content:space-between;align-items:center;gap:8px;margin-bottom:10px;font-size:14px;color:var(--muted)}
.timer{font-variant-numeric:tabular-nums;font-weight:700;color:var(--ink)}
.frac{display:inline-flex;flex-direction:column;vertical-align:middle;text-align:center;font-size:.9em;line-height:1.1;margin:0 .1em}.frac>span:first-child{border-bottom:1px solid currentColor;padding:0 .2em}.frac>span:last-child{padding:0 .2em}
.grid{display:grid;grid-template-columns:repeat(10,1fr);gap:4px}.grid button{padding:6px 0;border:1px solid var(--line);border-radius:6px;background:#fff;font-size:13px;cursor:pointer}.grid button.done{background:#dbe7ff}.grid button.cur{outline:2px solid var(--acc)}
.code{display:inline-block;font-size:12px;font-weight:800;color:#fff;background:var(--muted);border-radius:4px;padding:0 5px;margin-right:4px}
table.k{width:100%;border-collapse:collapse;font-size:15px}table.k td,table.k th{border-bottom:1px solid var(--line);padding:6px 4px;text-align:left;vertical-align:top}
input[type=text],input[type=password],input[type=tel],select{width:100%;font-size:18px;padding:12px;border:1px solid var(--line);border-radius:10px;margin:4px 0 12px;background:#fff}
label{font-weight:600}.err{color:var(--bad);font-weight:600}
details summary{cursor:pointer;font-weight:700;color:var(--acc)}
@media (max-width:420px){body{font-size:16px}.grid{grid-template-columns:repeat(8,1fr)}}

.ok-msg{background:#e8f5ec;border:1px solid #bfe0c9;border-radius:8px;padding:10px;margin:0 0 10px}
.enlace{font-size:.72rem;word-break:break-all;margin-top:4px}
.btn.small{width:auto;padding:4px 10px;font-size:.8rem}