:root{
  --bg:#f5f7f4; --surface:#fff; --surface-2:#eef3ee; --text:#202622; --muted:#68736b;
  --line:#dce4dd; --green:#2f6b4f; --green-2:#3f8060; --green-soft:#e6f0e8;
  --red:#b94a48; --red-soft:#fbeaea; --orange:#c77922; --orange-soft:#fff2df;
  --shadow:0 10px 30px rgba(31,49,38,.07); --radius:18px;
}
*{box-sizing:border-box} html{scroll-behavior:smooth} body{margin:0;background:var(--bg);color:var(--text);font-family:Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",sans-serif;line-height:1.5}
a{color:inherit;text-decoration:none} button,input{font:inherit}
.topbar{height:72px;background:rgba(255,255,255,.94);backdrop-filter:blur(8px);border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;padding:0 max(24px,calc((100% - 1180px)/2));position:sticky;top:0;z-index:10}
.topbar.compact{position:static}
.brand{display:flex;align-items:center;gap:10px}.brand-mark{font-size:25px}.brand strong{display:block;letter-spacing:.06em;font-size:15px}.brand small{display:block;color:var(--muted);font-size:11px;margin-top:-2px}
.topnav{display:flex;gap:22px;font-size:14px;color:var(--muted)}.topnav a:hover,.text-link:hover{color:var(--green)}
.container{max-width:1180px;margin:0 auto;padding:34px 24px 70px}
.hero{display:flex;justify-content:space-between;align-items:center;min-height:230px;padding:35px 42px;background:linear-gradient(135deg,#e9f2ea,#f8faf7);border:1px solid var(--line);border-radius:28px;box-shadow:var(--shadow);overflow:hidden}
.eyebrow{font-size:11px;font-weight:800;letter-spacing:.12em;color:var(--green);text-transform:uppercase}.hero h1{font-size:clamp(32px,5vw,56px);line-height:1.05;margin:10px 0 14px;letter-spacing:-.04em}.hero h1 span{color:var(--green)}.hero p{color:var(--muted);max-width:650px;margin:0;font-size:16px}.hero-leaf{font-size:100px;opacity:.75;transform:rotate(-8deg)}
.stats-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin:22px 0}.stat-card,.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}.stat-card{padding:20px}.stat-card .value{font-size:28px;font-weight:800}.stat-card .label{font-size:12px;color:var(--muted);margin-top:3px}
.action-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}.action-card{display:flex;align-items:center;gap:14px;background:var(--surface);border:1px solid var(--line);border-radius:16px;padding:18px;transition:.18s;box-shadow:0 5px 18px rgba(31,49,38,.04)}.action-card:hover{transform:translateY(-2px);box-shadow:var(--shadow)}.action-card.primary{border-color:#b9d1c0;background:var(--green-soft)}.action-icon{width:42px;height:42px;border-radius:12px;display:grid;place-items:center;background:#f0f3f0;font-weight:800}.primary .action-icon{background:#d1e4d5;color:var(--green)}.action-card strong{display:block;font-size:14px}.action-card small{display:block;color:var(--muted);font-size:12px;margin-top:2px}
.section{margin-top:38px}.section-heading{display:flex;justify-content:space-between;align-items:end;margin-bottom:14px}.section h2{margin:4px 0 0;font-size:24px}.topic-table{overflow:hidden;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}.topic-row{display:grid;grid-template-columns:1fr 150px 150px;align-items:center;padding:17px 20px;border-bottom:1px solid var(--line)}.topic-row:last-child{border-bottom:0}.topic-row.head{font-size:11px;text-transform:uppercase;letter-spacing:.08em;color:var(--muted);background:#fafcfa}.topic-name{font-weight:700}.topic-meta{font-size:13px;color:var(--muted)}.accuracy{font-weight:800}.accuracy.good{color:var(--green)}.accuracy.low{color:var(--red)}
footer{text-align:center;color:#89938c;font-size:12px;padding:20px 20px 40px}
.test-container{max-width:900px}.test-head{display:flex;justify-content:space-between;align-items:center;margin-bottom:22px}.timer{font-variant-numeric:tabular-nums;font-weight:800;font-size:18px}.question-number{color:var(--muted);font-weight:700}.config-title{margin:0 0 6px;font-size:32px}.config-subtitle{color:var(--muted);margin:0 0 25px}.config-section{margin:24px 0}.config-section h3{font-size:13px;text-transform:uppercase;letter-spacing:.09em;margin:0 0 10px}.choice-grid{display:flex;flex-wrap:wrap;gap:10px}.choice{position:relative}.choice input{position:absolute;opacity:0}.choice label{display:flex;align-items:center;justify-content:center;min-width:92px;padding:12px 17px;border:1px solid var(--line);background:var(--surface);border-radius:12px;cursor:pointer;font-weight:700;font-size:14px}.choice input:checked+label{border-color:var(--green);background:var(--green-soft);color:var(--green)}.custom-time{display:flex;align-items:center;gap:18px}.stepper{display:flex;align-items:center;border:1px solid var(--line);border-radius:13px;background:#fff;overflow:hidden}.stepper button{border:0;background:#f4f6f4;width:45px;height:45px;cursor:pointer;font-size:20px}.stepper strong{min-width:82px;text-align:center}.topic-tree{background:var(--surface);border:1px solid var(--line);border-radius:16px;overflow:hidden}.tree-toolbar{display:flex;justify-content:space-between;align-items:center;padding:14px 16px;border-bottom:1px solid var(--line);background:#fafcfa}.tree-toolbar label{font-weight:800;font-size:14px}.tree-row{padding:13px 16px;border-bottom:1px solid #edf1ed}.tree-row:last-child{border-bottom:0}.tree-parent{display:flex;align-items:center;gap:9px;font-weight:800}.tree-parent .toggle{margin-left:auto;border:0;background:none;cursor:pointer;color:var(--muted)}.subtree{margin:9px 0 0 29px;display:grid;gap:7px}.subtree label{display:flex;gap:9px;align-items:center;color:#4e5951;font-size:14px}.checkbox{accent-color:var(--green)}.partial{position:relative}.partial::after{content:"";position:absolute;left:3px;top:8px;width:8px;height:2px;background:var(--green);border-radius:2px}
.btn-row{display:flex;justify-content:flex-end;gap:10px;margin-top:25px}.btn{border:1px solid var(--line);background:#fff;border-radius:12px;padding:12px 18px;font-weight:800;cursor:pointer}.btn:hover{filter:brightness(.98)}.btn.primary{background:var(--text);color:#fff;border-color:var(--text)}.btn.green{background:var(--green);color:#fff;border-color:var(--green)}.btn.danger{color:var(--red);border-color:#e8c9c8;background:#fff}.btn:disabled{opacity:.45;cursor:not-allowed}
.confirm-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:10px}.confirm-item{padding:15px;background:var(--surface-2);border-radius:13px}.confirm-item small{display:block;color:var(--muted);font-size:11px;text-transform:uppercase;letter-spacing:.07em}.confirm-item strong{display:block;margin-top:3px}
.question-card{background:var(--surface);border:1px solid var(--line);border-radius:22px;box-shadow:var(--shadow);padding:30px}.question-card.review{border:2px solid #e0a14c}.review-badge{display:inline-flex;align-items:center;gap:5px;background:var(--orange-soft);color:var(--orange);padding:6px 10px;border-radius:999px;font-size:11px;font-weight:900;margin-bottom:14px}.question-text{font-size:23px;line-height:1.35;margin:0 0 25px;letter-spacing:-.01em}.answers{display:grid;gap:10px}.answer{display:flex;gap:13px;align-items:flex-start;width:100%;padding:16px;border:1px solid var(--line);background:#fff;border-radius:14px;text-align:left;cursor:pointer}.answer:hover{border-color:#b7c9bc;background:#fafcf9}.answer.selected{border:2px solid var(--green);background:var(--green-soft);padding:15px}.answer-key{width:29px;height:29px;display:grid;place-items:center;border-radius:8px;background:#f0f2f0;font-weight:900;font-size:12px;flex:none}.selected .answer-key{background:#cfe3d3;color:var(--green)}.answer-text{font-size:15px}.test-actions{display:flex;justify-content:space-between;gap:10px;margin-top:16px}.test-actions .right{display:flex;gap:10px}.empty{padding:35px;text-align:center;color:var(--muted)}
.results-hero{text-align:center;padding:30px 0}.score-ring{width:150px;height:150px;border-radius:50%;margin:15px auto;display:grid;place-items:center;background:conic-gradient(var(--green) var(--score),#e6ece7 0);position:relative}.score-ring::after{content:"";position:absolute;inset:10px;background:var(--bg);border-radius:50%}.score-ring strong{position:relative;z-index:1;font-size:29px}.result-stats{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin:20px 0}.result-stat{padding:16px;text-align:center;background:var(--surface);border:1px solid var(--line);border-radius:14px}.result-stat strong{font-size:25px;display:block}.result-stat small{color:var(--muted)}.correct{color:var(--green)}.wrong{color:var(--red)}.blank{color:#7e8881}
.review-toolbar{display:flex;gap:7px;flex-wrap:wrap;margin:20px 0}.filter-btn{border:1px solid var(--line);background:#fff;border-radius:999px;padding:8px 14px;cursor:pointer;font-size:12px;font-weight:800}.filter-btn.active{background:var(--text);color:#fff;border-color:var(--text)}.review-item{background:var(--surface);border:1px solid var(--line);border-radius:18px;margin:12px 0;padding:20px}.review-item .q{font-weight:800;margin-bottom:13px}.review-option{padding:9px 11px;border-radius:9px;font-size:13px;margin:5px 0;background:#f7f8f7}.review-option.chosen{outline:2px solid #a9c3ae}.review-option.correct-answer{background:var(--green-soft)}.review-option.chosen.wrong-answer{background:var(--red-soft)}.explanation{margin-top:12px;padding:13px;background:#f6f8f6;border-left:3px solid var(--green);color:#566159;font-size:13px}
.stats-overview{display:grid;grid-template-columns:repeat(6,1fr);gap:10px;margin:22px 0}.stats-table{overflow:hidden;background:#fff;border:1px solid var(--line);border-radius:18px}.stats-line{display:grid;grid-template-columns:1fr repeat(3,120px);padding:14px 18px;border-bottom:1px solid var(--line)}.stats-line:last-child{border:0}.stats-line.head{font-size:11px;text-transform:uppercase;letter-spacing:.08em;color:var(--muted);background:#fafcfa}
.toast{position:fixed;bottom:20px;right:20px;background:var(--text);color:#fff;padding:12px 16px;border-radius:12px;box-shadow:var(--shadow);z-index:20}

.finish-test{color:var(--red);border-color:#e8c9c8;background:#fff}
.finish-test:hover{background:var(--red-soft)}
.modal-backdrop{position:fixed;inset:0;background:rgba(20,28,22,.45);display:grid;place-items:center;padding:20px;z-index:1000}
.modal-card{width:min(520px,100%);background:#fff;border-radius:22px;box-shadow:0 20px 60px rgba(0,0,0,.2);padding:28px}
.modal-card h2{margin:6px 0 10px;font-size:25px}
.modal-card p{color:var(--muted);line-height:1.55;margin:0}
.modal-actions{display:flex;justify-content:flex-end;gap:10px;margin-top:24px;flex-wrap:wrap}

/* V1.2 — immediate answer feedback */
.answer.correct-answer{border-color:#3b8f57;background:#edf8ef}
.answer.wrong{border-color:#c64b4b;background:#fff0f0}
.answer.correct{border-color:#3b8f57;background:#edf8ef}
.answer.wrong .answer-key{background:#f4d1d1;color:#a52e2e}
.answer.correct .answer-key{background:#cfe8d5;color:#246c3b}
.answer:disabled{cursor:default;opacity:1}
.answer:disabled:hover{border-color:var(--line);background:#fff}
.answer.correct-answer:disabled:hover,.answer.correct:disabled:hover{border-color:#3b8f57;background:#edf8ef}
.answer.wrong:disabled:hover{border-color:#c64b4b;background:#fff0f0}
.answer-feedback{margin-top:32px;border-radius:14px;padding:15px 17px;border:1px solid}
.feedback-correct{background:#edf8ef;border-color:#b9ddc2;color:#245d35}
.feedback-wrong{background:#fff0f0;border-color:#e5b7b7;color:#7e2727}
.feedback-title{font-weight:900;letter-spacing:.02em}
.answer-feedback p{margin:6px 0 0;font-size:14px}
.explanation-panel{margin-top:16px;border:1px solid var(--line);border-radius:14px;background:#fafcf9;overflow:hidden}
.explanation-panel summary{cursor:pointer;padding:13px 16px;font-weight:800;color:#315b3d;list-style:none}
.explanation-panel summary::-webkit-details-marker{display:none}
.explanation-body{padding:0 16px 16px;font-size:14px;line-height:1.55;color:#3e4941}
.explanation-body p{margin:8px 0}
.explanation-body .reference{padding-top:10px;border-top:1px solid var(--line);color:#52625a}

/* V1.5 — referencias sin explicación */
.reference-only{margin-top:16px;padding:13px 16px;border:1px solid var(--line);border-radius:14px;background:#fafcf9;color:#52625a;font-size:14px;line-height:1.55}


/* V1.6 · Estadísticas */
.stats-topic-table .stats-line { grid-template-columns: 2.2fr .7fr 1fr .8fr .6fr; }
.stats-help { margin-bottom: 40px; }
.stats-help .btn { margin-top: 12px; }
.stats-empty-state { min-height: 180px; }
@media (max-width: 760px) {
  .stats-topic-table { overflow-x: auto; }
  .stats-topic-table .stats-line { min-width: 650px; }
}