/* Tipografía del sistema: sin descargas de fuentes ni peticiones a terceros. */
:root{--nav:#172735;--nav-2:#233848;--ink:#223240;--muted:#647483;--line:#e3e9e8;--paper:#f8faf9;--white:#fff;--accent:#d96340;--accent-light:#fff1eb;--teal:#1e8075;--teal-light:#e9f6f2;--blue-light:#e9f1fa;--yellow:#fbf0dc;--shadow:0 8px 26px rgba(34,50,64,.052);font-synthesis:none}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;font-family:system-ui,-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;background:var(--paper);color:var(--ink);font-size:15px;line-height:1.65}button,input,textarea,select{font:inherit}button{cursor:pointer}a{color:var(--teal)}a:hover{text-decoration-color:var(--accent)}.site-shell{min-height:100vh;display:flex}.sidebar{position:fixed;inset:0 auto 0 0;width:266px;overflow-y:auto;background:var(--nav);color:#dce7e8;z-index:20;padding:30px 17px 21px;display:flex;flex-direction:column;scrollbar-color:#576879 transparent;scrollbar-width:thin}.brand{padding:2px 8px 32px}.brand-link{display:flex;gap:12px;align-items:center;color:#fff;text-decoration:none}.brand-link:hover{text-decoration:none}.brand-mark{display:grid;place-items:center;width:41px;height:41px;border-radius:12px;background:#ed946f;color:#172735;font-family:Georgia,serif;font-weight:800;font-size:27px;line-height:1}.brand-mark span{color:#fff}.brand strong{display:block;font-family:system-ui,sans-serif;letter-spacing:.04em;font-size:19px}.brand small{display:block;font-size:9px;letter-spacing:.12em;font-weight:700;opacity:.7}.sidebar-heading{font-size:10px;color:#91a4ab;letter-spacing:.125em;font-weight:800;padding:0 16px;margin:6px 0 11px}.unit-heading,.next-heading{margin-top:25px}.side-nav{display:flex;flex-direction:column;gap:3px}.nav-link{display:flex;align-items:center;gap:11px;color:#c0d1d5;border-radius:10px;padding:10px 12px;text-decoration:none;font-size:12.8px;font-weight:600;line-height:1.25;min-height:41px;transition:background .15s,color .15s}.nav-link:hover{color:#fff;background:#293f4e;text-decoration:none}.nav-link.active{color:#fff;background:#344a57}.nav-link.active::before{content:"";width:3px;height:22px;background:#ffa980;border-radius:5px;position:absolute;margin-left:-12px}.nav-icon{width:19px;flex-shrink:0;text-align:center;color:#a3b8ba;font-weight:800;font-size:16px}.nav-link.active .nav-icon{color:#ffc39c}.nav-tail{margin-left:auto;color:#a2b8b7}.nav-check{margin-left:auto;font-size:12px;color:#9be7cc}.sidebar-progress{margin-top:auto;margin-bottom:21px;padding:20px 12px 0}.progress-label{display:flex;justify-content:space-between;align-items:center;font-size:12px}.progress-label strong{color:#bce3d6}.progress-track{height:6px;background:#344b55;border-radius:8px;margin:13px 0 12px;overflow:hidden}.progress-fill{height:100%;width:0;background:#7ac3ab;border-radius:8px;transition:width .35s}.sidebar-progress small{display:block;font-size:10.5px;line-height:1.5;color:#8fa3ab}.sidebar-foot{border-top:1px solid #344553;padding:17px 10px 0;color:#96a8b0;font-size:10.7px;line-height:1.8}.main-column{margin-left:266px;min-width:0;width:calc(100% - 266px);display:flex;flex-direction:column}.topbar{height:75px;background:rgba(255,255,255,.92);border-bottom:1px solid var(--line);display:flex;justify-content:space-between;align-items:center;padding:0 clamp(26px,5.5vw,90px);position:sticky;top:0;z-index:10;backdrop-filter:blur(12px)}.topbar-trail{font-size:12.5px;color:#87949b;font-weight:600}.topbar-trail span:last-child{color:#364e59}.trail-separator{margin:0 14px;color:#b3bdc0}.topbar-tools{display:flex;align-items:center;gap:18px}.level-pill{display:flex;align-items:center;gap:8px;border:1px solid #d5e9e4;border-radius:50px;padding:5px 12px;color:var(--teal);background:#f2f9f6;font-size:11px;font-weight:800;letter-spacing:.03em}.level-dot{width:6px;height:6px;background:#3c9a87;border-radius:50%}.text-tool{background:transparent;border:0;color:#71818b;font-size:12px;font-weight:700;padding:5px}.text-tool:hover{color:var(--teal)}.mobile-menu,.close-menu{display:none}.icon-button{border:0;background:none;color:inherit}.main-footer{padding:22px clamp(26px,5.5vw,90px);border-top:1px solid var(--line);display:flex;justify-content:space-between;gap:14px;flex-wrap:wrap;font-size:11px;color:#87949d}main{width:100%;max-width:1350px;margin:0 auto;flex:1;padding:45px clamp(26px,5.5vw,90px) 85px;outline:none}.eyebrow{display:inline-block;color:var(--accent);text-transform:uppercase;font-size:11px;letter-spacing:.17em;font-weight:800;margin-bottom:13px}.page-title{font-family:system-ui,-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;font-size:clamp(34px,3.7vw,50px);letter-spacing:-.055em;line-height:1.17;font-weight:800;color:#213547;margin:0 0 17px}.lead{font-size:16px;line-height:1.85;color:#5e707d;max-width:740px;margin:0 0 28px}.hero{border-radius:21px;position:relative;overflow:hidden;background:#1b3542;color:#fff;padding:48px 50px;margin-bottom:28px;min-height:285px;display:flex;align-items:center}.hero-content{position:relative;z-index:2;max-width:650px}.hero .eyebrow{color:#f3b08e}.hero h1{font-family:system-ui,sans-serif;font-size:clamp(35px,4.7vw,59px);letter-spacing:-.055em;line-height:1.12;margin:0 0 18px}.hero p{color:#d0dfdc;max-width:520px;font-size:15.5px;margin:0 0 26px}.hero::before{content:"";position:absolute;right:-145px;top:-180px;height:480px;width:480px;border:78px solid #35595e;opacity:.75;border-radius:50%}.hero::after{content:"";position:absolute;right:130px;bottom:-165px;height:330px;width:330px;border:53px solid #41665c;opacity:.38;border-radius:50%}.hero .hero-symbol{position:absolute;right:48px;top:22px;z-index:1;font-family:Georgia,serif;font-size:190px;line-height:1;color:#f3bd91;opacity:.9;transform:rotate(-12deg)}.hero-subtitle{display:inline-flex;background:rgba(255,255,255,.12);border:1px solid rgba(255,255,255,.13);border-radius:22px;padding:5px 13px;font-size:11px;font-weight:700;color:#e6f6ef}.button{display:inline-flex;justify-content:center;align-items:center;gap:9px;background:var(--teal);border:1px solid var(--teal);color:#fff;border-radius:10px;padding:11px 17px;font-weight:800;font-size:12.7px;line-height:1.4;text-decoration:none;transition:transform .1s,background .2s}.button:hover{background:#12695e;text-decoration:none;color:white}.button:active{transform:translateY(1px)}.button-light{background:#fff;border-color:#fff;color:#19333e}.button-light:hover{background:#e9f5ef;border-color:#e9f5ef;color:#19333e}.button-outline{background:white;color:var(--teal);border:1px solid #cbded9}.button-outline:hover{background:#e9f6f2;color:#155e56}.button-small{padding:8px 12px;font-size:11px;border-radius:8px}.button-danger{color:#a34d36;border-color:#f2d2ca;background:#fff}.button-danger:hover{background:#fff0eb;color:#a34d36}.section-heading{display:flex;align-items:flex-end;justify-content:space-between;gap:14px;margin:40px 0 19px}.section-heading h2,.content-heading{font-family:system-ui,sans-serif;font-size:24px;letter-spacing:-.045em;line-height:1.3;color:#22394b;margin:0}.section-heading p{color:#87969d;font-size:12px;margin:0}.card-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:17px}.tile{border:1px solid var(--line);background:var(--white);border-radius:15px;padding:23px;text-decoration:none;display:block;color:inherit;box-shadow:var(--shadow);transition:transform .15s,border-color .15s}.tile:hover{transform:translateY(-2px);border-color:#a5cfc4;text-decoration:none}.tile-icon{display:grid;place-items:center;background:var(--teal-light);height:37px;width:37px;border-radius:10px;color:var(--teal);font-size:19px;margin-bottom:17px}.tile.warm .tile-icon{background:var(--accent-light);color:var(--accent)}.tile.blue .tile-icon{background:var(--blue-light);color:#547da4}.tile.gold .tile-icon{background:#fff6e2;color:#b4873b}.tile h3{font-family:system-ui,sans-serif;font-size:16.5px;letter-spacing:-.025em;margin:0 0 7px}.tile p{font-size:12.8px;color:#7a8992;line-height:1.65;margin:0}.tile-footer{display:flex;justify-content:space-between;align-items:center;color:var(--teal);font-weight:800;font-size:11.5px;margin-top:20px}.module-index{color:#9faab0;font-size:10px;font-weight:800;letter-spacing:.08em}.intro-stats{display:grid;grid-template-columns:repeat(3,1fr);gap:13px;margin:26px 0 0}.mini-stat{background:#fff;border:1px solid var(--line);border-radius:13px;padding:17px 20px}.mini-stat strong{font-family:system-ui,sans-serif;color:#253d47;font-size:27px;letter-spacing:-.06em;display:block;line-height:1.25}.mini-stat small{font-size:11px;color:#7e8d94}.notice{background:var(--teal-light);border:1px solid #d0e9de;border-radius:12px;padding:18px 20px;color:#335d59;margin:25px 0;font-size:13px}.notice.warm{background:#fff7e9;border-color:#f2e4c5;color:#6b5b3e}.notice strong{color:#214a43}.chapter-header{padding-bottom:28px;border-bottom:1px solid var(--line);margin-bottom:29px}.chapter-header .page-title{max-width:850px}.chapter-header .lead{margin:0}.chapter-meta{margin:19px 0 0;display:flex;flex-wrap:wrap;gap:8px}.meta-chip{display:inline-flex;align-items:center;gap:7px;background:white;border:1px solid var(--line);border-radius:22px;padding:5px 10px;font-size:11px;color:#75838b;font-weight:700}.lesson-block{margin:30px 0 33px}.lesson-block h2{font-family:system-ui,sans-serif;font-size:23px;letter-spacing:-.045em;margin:0 0 15px}.lesson-block h3{font-family:system-ui,sans-serif;font-size:17px;letter-spacing:-.025em;margin:21px 0 12px}.lesson-block p{color:#526573;margin:12px 0;font-size:14px}.rule-card{background:#fff;border:1px solid var(--line);border-radius:14px;padding:23px 25px;margin:17px 0;box-shadow:var(--shadow)}.rule-card h3{margin:0 0 12px!important}.rule-card p{margin:9px 0}.rule-card ul,.rule-card ol{padding-left:22px;margin:12px 0}.rule-card li{margin:6px 0;font-size:13.5px;color:#435866}.example{background:#f4f8f7;border-left:3px solid #6da99a;border-radius:0 7px 7px 0;padding:12px 16px;margin:14px 0;font-size:13.4px;color:#2b4b4b}.example b{color:#176f62}.example .translation{display:block;font-size:12px;color:#7b8c90;margin-top:3px}.note-badge{display:inline-block;background:#fae8df;border-radius:5px;padding:1px 7px;color:#a55436;font-size:10px;font-weight:800;text-transform:uppercase;letter-spacing:.055em;margin:2px 8px 0 0}.rule-split{display:grid;grid-template-columns:1fr 1fr;gap:15px}.compare-card{padding:18px 19px;border:1px solid var(--line);border-radius:12px;background:#fff}.compare-card h4{font-size:13px;color:#196d63;margin:0 0 8px}.compare-card.danger h4{color:#bf6949}.compare-card p{font-size:13.3px;line-height:1.6;margin:0 0 8px}.compare-card small{font-size:11px;color:#8b98a0}.content-table{border-collapse:collapse;width:100%;background:#fff;border:1px solid var(--line);border-radius:12px;overflow:hidden;font-size:13px}.content-table th{text-align:left;background:#ecf4f2;color:#2f645b;font-size:11.5px;font-weight:800}.content-table th,.content-table td{padding:12px 14px;border-bottom:1px solid #e9efed;vertical-align:top}.content-table tr:last-child td{border-bottom:0}.content-table td:first-child{font-weight:700;color:#2b4856}.table-scroll{overflow-x:auto;border-radius:12px;border:1px solid var(--line)}.table-scroll .content-table{border:0}.vocab-categories{display:flex;flex-wrap:wrap;gap:8px;margin:20px 0}.filter-chip{border:1px solid #d5e3e1;background:#fff;color:#627783;border-radius:24px;padding:8px 13px;font-size:11.6px;font-weight:800}.filter-chip[aria-pressed="true"]{background:#236c65;border-color:#236c65;color:#fff}.vocab-search{background:white;border:1px solid var(--line);padding:11px 14px;border-radius:10px;width:min(100%,390px);outline:none}.vocab-search:focus,input:focus,textarea:focus,select:focus{border-color:#45998a!important;outline:3px solid rgba(69,153,138,.16)}.vocab-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;margin:15px 0 30px}.vocab-card{border:1px solid var(--line);background:white;border-radius:12px;padding:16px 18px}.vocab-card strong{font-size:13.5px;color:#224b4c}.vocab-card p{font-size:12.5px;margin:6px 0 5px;color:#5e737c}.vocab-card em{font-size:11.7px;color:#a3694d;font-style:normal}.vocab-empty{font-size:13px;color:#7b8790;margin:20px 0}.reading-text{max-width:790px;background:#fff;border:1px solid var(--line);border-radius:16px;padding:33px 40px;box-shadow:var(--shadow);margin:22px 0}.reading-text h2{font-family:Georgia,serif;font-size:27px;letter-spacing:-.025em;margin:0 0 19px}.reading-text p{font-family:Georgia,'Times New Roman',serif;color:#3a4a54;font-size:16px;line-height:1.95;margin:0 0 18px}.reading-text p:last-child{margin:0}.reading-text .reading-credit{font-family:system-ui,sans-serif;font-size:11px;color:#8c9aa1;font-style:italic;margin-top:21px}.exercise-panel{background:#fff;border:1px solid #dde7e3;border-radius:17px;padding:25px;margin:31px 0;box-shadow:var(--shadow)}.exercise-head{display:flex;align-items:flex-start;justify-content:space-between;gap:12px;margin-bottom:8px}.exercise-panel .exercise-kicker{color:#c56a46;font-size:10px;font-weight:800;letter-spacing:.13em;text-transform:uppercase;margin-bottom:8px}.exercise-panel h2{font-family:system-ui,sans-serif;font-size:22px;letter-spacing:-.04em;margin:0}.exercise-note{font-size:12.4px;color:#788891;margin:9px 0 21px}.score-label{background:#e8f5ef;color:#1a7163;border-radius:30px;padding:6px 11px;font-weight:800;font-size:11px;white-space:nowrap}.question{padding:19px 0 20px;border-top:1px solid #edf0f0}.question-top{display:flex;align-items:flex-start;gap:13px}.question-num{display:grid;place-items:center;background:#f1f5f4;border-radius:8px;color:#768892;width:29px;height:29px;font-weight:800;font-size:11px;flex-shrink:0}.question-body{flex:1;min-width:0}.question-prompt{font-weight:700;font-size:13.5px;color:#2a404e;line-height:1.6;margin-bottom:12px}.question-hint{color:#80939b;font-size:11px;margin:0 0 10px}.options{display:flex;flex-wrap:wrap;gap:8px}.option{display:flex;align-items:center;gap:8px;background:#f8faf9;border:1px solid #e2eae7;border-radius:9px;padding:9px 13px;font-size:12.8px;cursor:pointer;line-height:1.5}.option:hover{border-color:#9bc9b9}.option:has(input:checked){background:#e7f5f0;border-color:#61a99a;color:#1b6f64}.option input{accent-color:#278778;cursor:pointer}.answer-input,.reflection-box{width:100%;max-width:560px;border:1px solid #d4e1dd;border-radius:9px;background:#fff;padding:10px 13px;color:#243e4a;outline:none;font-size:13px}.answer-input::placeholder{color:#aebabb}.feedback{margin-top:11px;background:#f1f9f4;border-radius:8px;padding:10px 13px;font-size:12px;color:#316458;line-height:1.65}.feedback.wrong{background:#fff4ed;color:#8f563b}.feedback strong{display:block;font-size:11.5px;margin-bottom:1px}.question.correct .question-num{background:#dff5e9;color:#1c805a}.question.incorrect .question-num{background:#fff0e8;color:#b3613e}.exercise-actions{border-top:1px solid #edf0f0;padding-top:18px;margin-top:3px;display:flex;gap:10px;align-items:center;flex-wrap:wrap}.exercise-summary{font-size:12px;color:#496a64;font-weight:700;margin-left:auto}.exercise-summary.low{color:#b76c43}.activity-tag{padding:4px 9px;border-radius:7px;background:#eaf4f3;color:#29796a;font-size:10px;font-weight:800}.reflection-panel{margin:23px 0;border-radius:15px;background:#fff;border:1px solid var(--line);padding:25px}.reflection-panel h2{font-family:system-ui,sans-serif;font-size:21px;letter-spacing:-.04em;margin:0 0 8px}.reflection-panel p{color:#637682;font-size:13px;margin:7px 0}.reflection-box{max-width:none;min-height:155px;resize:vertical;margin-top:11px}.reflection-actions{display:flex;align-items:center;gap:12px;flex-wrap:wrap;margin-top:13px}.save-status{font-size:11px;color:#6b8f84}.reflection-checklist{display:flex;flex-wrap:wrap;gap:10px;margin-top:15px}.reflection-checklist label{font-size:11.5px;color:#556772;display:flex;align-items:center;gap:5px}.reflection-checklist input{accent-color:#26786f}.intonation-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:13px}.intonation-card{border:1px solid var(--line);border-radius:13px;background:#fff;padding:18px}.intonation-card h3{font-size:14px;margin:0 0 8px}.intonation-card .intonation-shape{font-family:Georgia,serif;color:#d76545;font-size:32px;letter-spacing:.03em;line-height:1.4}.intonation-card p{font-size:12.5px;margin:7px 0;color:#586d76}.intonation-card small{font-size:11px;color:#8b989d}.route-next{display:flex;align-items:center;justify-content:space-between;gap:15px;background:#e9f4f0;border-radius:12px;padding:20px 24px;margin-top:32px;text-decoration:none}.route-next:hover{background:#dceee7;text-decoration:none}.route-next span{font-size:10px;color:#487b72;text-transform:uppercase;letter-spacing:.1em;font-weight:800}.route-next strong{display:block;font-family:system-ui,sans-serif;font-size:17px;letter-spacing:-.035em;color:#214c45}.route-next .arrow{font-size:28px;color:#47897a}.lesson-list{display:grid;gap:10px}.lesson-row{background:white;border:1px solid var(--line);border-radius:11px;padding:15px 19px;display:flex;align-items:center;gap:13px;text-decoration:none;color:#274050}.lesson-row:hover{border-color:#a1cdbd;text-decoration:none}.lesson-row .list-index{background:#edf3f0;border-radius:9px;width:34px;height:34px;display:grid;place-items:center;flex-shrink:0;font-weight:800;font-size:11px;color:#59857b}.lesson-row strong{font-weight:700;font-size:13px}.lesson-row small{display:block;color:#88979e;font-size:11px;margin-top:2px}.lesson-row .list-tail{margin-left:auto;color:#5e9787}.not-ready{border:1px dashed #bdcec8;border-radius:16px;padding:35px;background:#fff;max-width:820px}.not-ready h2{font-family:system-ui,sans-serif;font-size:22px;margin:7px 0}.not-ready p{color:#657580;font-size:13px}.sr-only{position:absolute!important;clip:rect(0,0,0,0);width:1px;height:1px;overflow:hidden;white-space:nowrap}.skip-link{position:absolute;top:-60px;left:20px;padding:9px 15px;z-index:30;background:#fff}.skip-link:focus{top:10px}.tag-soft{background:#f7efeb;color:#b5694a;font-size:10px;padding:4px 8px;border-radius:20px;font-weight:800}.small-divider{height:1px;background:var(--line);margin:28px 0}.rubric{list-style:none;padding:0!important}.rubric li{border-bottom:1px solid var(--line);padding:9px 0 9px 25px;position:relative}.rubric li:before{content:'✓';position:absolute;left:0;color:var(--teal);font-weight:800}.source-note{color:#8b969b;font-size:11px;line-height:1.65;margin-top:15px}
@media(max-width:1120px){.sidebar{width:245px}.main-column{margin-left:245px;width:calc(100% - 245px)}main{padding:36px 40px 70px}.topbar{padding:0 40px}.hero{padding:39px}.hero .hero-symbol{right:20px;opacity:.45}.main-footer{padding:18px 40px}}
@media(max-width:900px){.sidebar{transform:translateX(-100%);transition:transform .2s ease;box-shadow:none}.sidebar.open{transform:translateX(0);box-shadow:10px 0 40px #0e222944}.main-column{margin-left:0;width:100%}.mobile-menu,.close-menu{display:inline-block}.close-menu{position:absolute;right:15px;top:28px;color:#cbdcdb}.mobile-scrim:not([hidden]){display:block;position:fixed;inset:0;background:#10263170;z-index:19}.topbar{height:65px;justify-content:flex-start;gap:18px}.topbar-tools{margin-left:auto}.hero .hero-symbol{right:30px}}
@media(max-width:620px){main{padding:25px 18px 58px}.topbar{padding:0 17px}.topbar .text-tool span{display:none}.hero{padding:32px 24px;min-height:270px}.hero .hero-symbol{display:none}.hero h1{font-size:37px}.card-grid,.rule-split,.vocab-grid,.intonation-grid{grid-template-columns:1fr}.intro-stats{grid-template-columns:repeat(3,1fr);gap:6px}.mini-stat{padding:12px}.mini-stat strong{font-size:20px}.mini-stat small{font-size:9px}.page-title{font-size:34px}.lead{font-size:14px}.rule-card,.exercise-panel,.reflection-panel{padding:19px}.question-top{gap:9px}.reading-text{padding:25px 20px}.reading-text p{font-size:15px}.section-heading{align-items:start}.main-footer{padding:18px}.exercise-summary{margin-left:0;width:100%}.level-pill{padding:4px 9px}}
@media print{.sidebar,.topbar,.main-footer,.mobile-scrim,.exercise-actions,.route-next,.reflection-actions,.vocab-categories,.vocab-search,.button{display:none!important}.main-column{margin:0;width:100%}main{max-width:none;padding:0 8px}.chapter-header{page-break-after:avoid}.rule-card,.exercise-panel,.reading-text,.compare-card{break-inside:avoid;box-shadow:none}.hero{color:#000;background:#fff;border:1px solid #888}.hero p,.hero .eyebrow{color:#444}body{background:white}.exercise-panel{page-break-inside:avoid}}