*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

    :root {
      --green:      #58cc02;
      --green-d:    #46a302;
      --green-bg:   #d7ffb8;
      --yellow:     #f5a623;
      --yellow-d:   #d48800;
      --red:        #ff4b4b;
      --red-d:      #cc0000;
      --red-bg:     #ffdfe0;
      --blue:       #1cb0f6;
      --blue-d:     #0090d9;
      --purple:     #ce82ff;
      --purple-d:   #a855f7;
      --white:      #ffffff;
      --bg:         #f0f4f8;
      --bg2:        #ffffff;
      --bg3:        #f8fafc;
      --border:     #e5e7eb;
      --border2:    #d1d5db;
      --text:       #1a1a2e;
      --text-dim:   #6b7280;
      --text-mid:   #4b5563;
      --locked:     #e5e7eb;
      --locked-d:   #d1d5db;
      --locked-txt: #9ca3af;
      --font:       'Nunito', sans-serif;
    }

    body {
      font-family: var(--font);
      background: var(--bg);
      color: var(--text);
      min-height: 100vh;
      display: flex;
      flex-direction: column;
    }

    /* ── NAVBAR (sin cambios) ── */
    .navbar {
      display: flex; align-items: center; justify-content: space-between;
      background: var(--white); padding: 0 32px; height: 68px;
      border-bottom: 2px solid var(--border);
      position: relative; top: 0; z-index: 200;
    }
    .navbar-logo { display: flex; align-items: center; gap: 10px; text-decoration: none; }
    .logo-img { width: 40px; height: 40px; object-fit: contain; }
    .logo-text { font-size: 1.4rem; font-weight: 900; color: var(--text); }

    .navbar-links {
      display: flex; list-style: none; gap: 8px;
      position: absolute; left: 50%; transform: translateX(-50%);
    }
    .navbar-links a {
      display: inline-flex; align-items: center; gap: 6px;
      padding: 8px 14px; border-radius: 24px; text-decoration: none;
      font-size: 0.9rem; font-weight: 700; color: var(--text-mid);
      transition: background .2s, color .2s; white-space: nowrap; line-height: 1;
    }
    .navbar-links a:hover { background: var(--bg); color: var(--text); }
    .navbar-links a.active { background: #dbeafe; color: var(--blue); }

    .navbar-auth { display: flex; align-items: center; gap: 12px; }
    .btn-entrar { font-weight: 700; color: var(--text-mid); text-decoration: none; padding: 8px 14px; font-family: var(--font); }
    .btn-registrarse {
      font-weight: 800; color: var(--white); background: var(--yellow);
      text-decoration: none; padding: 10px 22px; border-radius: 12px;
      box-shadow: 0 4px 0 var(--yellow-d); font-family: var(--font);
    }
    .btn-registrarse:hover { transform: translateY(-1px); }
    .nav-menu {
      position: fixed; top: 68px; left: -100%; width: 100%;
      height: calc(100vh - 68px); background-color: var(--white);
      transition: left 0.4s cubic-bezier(0.4, 0, 0.2, 1); z-index: 150;
    }
    .nav-menu.active { left: 0; }

    /* ── LEVEL TABS ── */
    .level-tabs-wrapper {
      background: var(--white);
      border-bottom: 2px solid var(--border);
      display: flex; justify-content: center;
      width: 100%;
      box-shadow: 0 2px 8px rgba(0,0,0,0.04);
    }
    .level-tab {
      display: flex; align-items: center; gap: 8px;
      padding: 14px 28px;
      font-family: var(--font); font-size: 0.88rem; font-weight: 800;
      color: var(--text-mid); background: none; border: none;
      border-bottom: 3px solid transparent;
      cursor: pointer; white-space: nowrap; letter-spacing: 0.5px; text-transform: uppercase;
      transition: color .2s, border-color .2s;
    }
    .level-tab:hover { color: var(--text); }
    .level-tab.active { color: var(--green); border-bottom-color: var(--green); }
    .tab-badge {
      background: var(--bg); border: 1px solid var(--border); border-radius: 20px;
      font-size: 0.7rem; font-weight: 800; padding: 2px 8px; color: var(--text-mid);
    }
    .level-tab.active .tab-badge { background: var(--green); color: var(--white); border-color: var(--green); }

    /* ── STATS BAR ── */
    .path-stats-bar {
      display: flex; justify-content: center; gap: 28px;
      background: var(--bg2); padding: 10px 16px; border-bottom: 2px solid var(--border);
    }
    .path-stat {
      display: flex; align-items: center; gap: 6px;
      font-weight: 900; font-size: 0.95rem; color: var(--text);
    }
    .path-stat-icon { font-size: 1.1rem; }
    .path-stat-sub { color: var(--text-dim); font-weight: 700; font-size: 0.85rem; }

    /* ── PATH ── */
    .path-main {
      flex: 1; display: flex; flex-direction: column; align-items: center;
      padding: 36px 20px 100px; width: 100%;
    }
    .level-panel { display: none; flex-direction: column; align-items: center; width: 100%; max-width: 440px; }
    .level-panel.active { display: flex; }

    /* ── UNIT HEADER ── */
    .unit-header {
      width: 100%; border-radius: 18px;
      padding: 18px 22px; margin-bottom: 6px;
      display: flex; align-items: center; justify-content: space-between;
      position: relative; overflow: hidden;
      box-shadow: 0 4px 14px rgba(0,0,0,0.08);
    }
    .unit-header-left { display: flex; flex-direction: column; gap: 2px; }
    .unit-label {
      font-size: 0.72rem; font-weight: 800;
      text-transform: uppercase; letter-spacing: 1.2px;
      color: rgba(255,255,255,0.8);
    }
    .unit-title { font-size: 1.1rem; font-weight: 900; color: #fff; }
    .unit-header-btn {
      background: rgba(255,255,255,0.2); border: 2px solid rgba(255,255,255,0.45);
      color: #fff; font-family: var(--font); font-weight: 800;
      font-size: 0.78rem; padding: 9px 16px; border-radius: 10px;
      cursor: pointer; transition: background .15s, transform .15s; letter-spacing: 0.3px;
    }
    .unit-header-btn:hover { background: rgba(255,255,255,0.32); transform: translateY(-1px); }

    /* ── PATH TRACK (recorrido tipo serpiente) ── */
    .path-track {
      display: flex; flex-direction: column; align-items: center;
      width: 100%; margin-bottom: 36px; padding: 28px 0 14px;
      position: relative;
    }
    .node-slot {
      display: flex; justify-content: center;
      width: 100%; margin-bottom: 4px; position: relative;
    }
    .node-connector {
      width: 6px; height: 26px; border-radius: 6px;
      background: var(--border2); margin: 0 auto 4px;
      position: relative; z-index: 1;
    }
    .node-connector.done { background: var(--green); }

    /* posiciones tipo zig-zag para el "camino" */
    .node-slot[data-pos="0"] .lesson-node { transform: translateX(0); }
    .node-slot[data-pos="1"] .lesson-node { transform: translateX(56px); }
    .node-slot[data-pos="2"] .lesson-node { transform: translateX(78px); }
    .node-slot[data-pos="3"] .lesson-node { transform: translateX(56px); }
    .node-slot[data-pos="4"] .lesson-node { transform: translateX(0); }
    .node-slot[data-pos="5"] .lesson-node { transform: translateX(-56px); }
    .node-slot[data-pos="6"] .lesson-node { transform: translateX(-78px); }
    .node-slot[data-pos="7"] .lesson-node { transform: translateX(-56px); }

    /* ── LESSON NODE ── */
    .lesson-node {
      position: relative; width: 84px; height: 84px;
      border-radius: 50%; border: none; cursor: pointer;
      display: flex; flex-direction: column; align-items: center; justify-content: center;
      font-family: var(--font); font-weight: 900;
      transition: transform 0.25s cubic-bezier(.34,1.56,.64,1), box-shadow 0.15s;
      outline: none; flex-shrink: 0;
    }
    .node-theme-label {
      position: absolute; top: calc(100% + 6px); left: 50%; transform: translateX(-50%);
      font-size: 0.72rem; font-weight: 800; color: var(--text-mid);
      white-space: nowrap; pointer-events: none;
    }

    .node-empezar {
      position: absolute; top: -40px; left: 50%; transform: translateX(-50%);
      background: var(--text); color: var(--white); border: none;
      font-family: var(--font); font-weight: 900; font-size: 0.76rem;
      padding: 6px 14px; border-radius: 10px; cursor: pointer;
      white-space: nowrap; letter-spacing: 0.3px; pointer-events: none;
      box-shadow: 0 2px 8px rgba(0,0,0,0.18);
      animation: floatLabel 1.6s ease-in-out infinite;
    }
    @keyframes floatLabel { 0%,100%{ transform:translateX(-50%) translateY(0);} 50%{ transform:translateX(-50%) translateY(-4px);} }
    .node-empezar::after {
      content: ''; position: absolute;
      top: 100%; left: 50%; transform: translateX(-50%);
      border: 6px solid transparent; border-top-color: var(--text);
    }

    .lesson-node.state-done {
      background: var(--green); box-shadow: 0 5px 0 var(--green-d);
      color: var(--white); pointer-events: auto;
    }
    .lesson-node.state-done:hover { transform: translateY(-4px) translateX(var(--tx, 0)); }
    .lesson-node.state-done:active { transform: translateY(2px); box-shadow: 0 2px 0 var(--green-d); }

    .lesson-node.state-current {
      background: var(--yellow); box-shadow: 0 5px 0 var(--yellow-d);
      color: var(--white); pointer-events: auto;
      animation: pulseNode 2.4s ease-in-out infinite;
    }
    @keyframes pulseNode {
      0%,100%{ box-shadow: 0 5px 0 var(--yellow-d), 0 0 0 0 rgba(245,166,35,0.4); }
      50%    { box-shadow: 0 5px 0 var(--yellow-d), 0 0 0 14px rgba(245,166,35,0); }
    }
    .lesson-node.state-current:hover { transform: translateY(-4px); animation: none; }
    .lesson-node.state-current:active { transform: translateY(2px); }

    .lesson-node.state-locked {
      background: var(--locked); box-shadow: 0 5px 0 var(--locked-d);
      color: var(--locked-txt); pointer-events: none; cursor: default;
    }

    .node-icon { font-size: 1.9rem; line-height: 1; }
    .node-crown {
      position: absolute; top: -10px; right: -4px;
      font-size: 1.05rem; pointer-events: none;
    }

    .node-tooltip {
      position: absolute; bottom: calc(100% + 16px); left: 50%;
      transform: translateX(-50%);
      background: var(--text); color: var(--white); border: 2px solid transparent;
      font-size: 0.75rem; font-weight: 700;
      padding: 6px 12px; border-radius: 8px;
      white-space: nowrap; pointer-events: none;
      opacity: 0; transition: opacity .15s; z-index: 10;
      box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    }
    .node-tooltip::after {
      content: ''; position: absolute;
      top: 100%; left: 50%; transform: translateX(-50%);
      border: 5px solid transparent; border-top-color: var(--text);
    }
    .lesson-node:not(.state-locked):hover .node-tooltip { opacity: 1; }

    /* ── HOVER-TO-TRANSLATE ── */
    .word-hint {
      position: relative; display: inline-block;
      border-bottom: 2px dashed var(--blue); cursor: help;
      color: var(--blue); font-weight: 800;
    }
    .word-hint::after {
      content: attr(data-translate); position: absolute;
      bottom: calc(100% + 10px); left: 50%;
      transform: translateX(-50%) scale(0.85);
      background: #1a1a2e; color: #ffffff;
      font-size: 0.78rem; font-weight: 700; font-family: var(--font);
      padding: 5px 12px; border-radius: 8px; white-space: nowrap;
      pointer-events: none; opacity: 0;
      transition: opacity 0.15s ease, transform 0.15s ease;
      z-index: 100; box-shadow: 0 4px 16px rgba(0,0,0,0.18);
    }
    .word-hint::before {
      content: ''; position: absolute;
      bottom: calc(100% + 4px); left: 50%;
      transform: translateX(-50%) scale(0.85);
      border: 6px solid transparent; border-top-color: #1a1a2e;
      pointer-events: none; opacity: 0;
      transition: opacity 0.15s ease, transform 0.15s ease; z-index: 100;
    }
    .word-hint:hover::after, .word-hint:hover::before { opacity: 1; transform: translateX(-50%) scale(1); }

    /* ═══ GUÍA MODAL ═══ */
    .guide-modal-backdrop {
      position: fixed; inset: 0; background: rgba(0,0,0,0.4);
      z-index: 700; display: flex; align-items: center; justify-content: center;
      padding: 20px; opacity: 0; pointer-events: none; transition: opacity .25s;
    }
    .guide-modal-backdrop.open { opacity: 1; pointer-events: auto; }
    .guide-card {
      background: var(--white); border-radius: 24px; max-width: 480px; width: 100%;
      max-height: 82vh; overflow-y: auto; padding: 28px 26px; position: relative;
      transform: scale(0.92); transition: transform .3s cubic-bezier(.34,1.56,.64,1);
      box-shadow: 0 24px 60px rgba(0,0,0,0.2);
    }
    .guide-modal-backdrop.open .guide-card { transform: scale(1); }
    .guide-close {
      position: absolute; top: 16px; right: 16px; background: var(--bg);
      border: none; border-radius: 50%; width: 34px; height: 34px;
      font-size: 1.1rem; cursor: pointer; color: var(--text-mid);
    }
    .guide-tabs { display: flex; gap: 8px; margin-bottom: 18px; }
    .guide-tab-btn {
      background: var(--bg3); border: 2px solid var(--border); border-radius: 12px;
      padding: 8px 16px; font-family: var(--font); font-weight: 800; font-size: 0.85rem;
      color: var(--text-mid); cursor: pointer;
    }
    .guide-tab-btn.active { background: var(--blue); border-color: var(--blue); color: var(--white); }
    .guide-topic-title { font-size: 1.4rem; font-weight: 900; margin-bottom: 4px; }
    .guide-summary { color: var(--text-mid); font-weight: 600; margin-bottom: 18px; line-height: 1.5; }
    .guide-section-title {
      font-size: 0.78rem; font-weight: 900; text-transform: uppercase; letter-spacing: 0.6px;
      color: var(--blue-d); margin: 16px 0 8px;
    }
    .guide-list { list-style: none; display: flex; flex-direction: column; gap: 8px; }
    .guide-list li {
      background: var(--bg3); border: 1px solid var(--border); border-radius: 10px;
      padding: 10px 14px; font-weight: 700; font-size: 0.9rem; line-height: 1.4;
    }
    .guide-list.examples li { color: var(--green-d); background: var(--green-bg); border-color: transparent; }
    .guide-list.mistakes li { color: var(--red-d); background: var(--red-bg); border-color: transparent; }
    .guide-list.tips li { color: var(--yellow-d); background: #fff6e0; border-color: transparent; }

    /* ═══ LESSON MODAL ═══ */
    .lesson-modal-backdrop {
      position: fixed; inset: 0; background: var(--bg);
      z-index: 600; display: flex; flex-direction: column;
      opacity: 0; pointer-events: none; transition: opacity .2s;
    }
    .lesson-modal-backdrop.open { opacity: 1; pointer-events: auto; }

    .lesson-topbar {
      display: flex; align-items: center; gap: 16px;
      padding: 16px 20px; border-bottom: 2px solid var(--border);
      background: var(--white);
    }
    .lesson-close-btn {
      background: none; border: none; cursor: pointer;
      color: var(--text-mid); font-size: 1.4rem; padding: 4px;
      line-height: 1; transition: color .15s;
    }
    .lesson-close-btn:hover { color: var(--text); }
    .lesson-progress-wrap { flex: 1; display: flex; flex-direction: column; gap: 4px; }
    .lesson-progress-bar {
      height: 16px; background: var(--border); border-radius: 99px;
      overflow: hidden; position: relative;
    }
    .lesson-progress-fill {
      height: 100%; background: var(--blue); border-radius: 99px; width: 0%;
      transition: width 0.4s cubic-bezier(.34,1.56,.64,1);
    }
    .lesson-progress-label { font-size: 0.7rem; font-weight: 800; color: var(--text-dim); align-self: flex-end; }
    .lesson-hearts { display: flex; gap: 3px; font-size: 1.15rem; white-space: nowrap; }
    .heart { transition: transform .2s; }
    .heart.lost { filter: grayscale(1) opacity(0.35); animation: heartLose .4s ease; }
    @keyframes heartLose { 0%{ transform:scale(1.4); } 100%{ transform:scale(1); } }

    .lesson-body {
      flex: 1; display: flex; flex-direction: column;
      padding: 32px 24px 140px; max-width: 620px;
      margin: 0 auto; width: 100%; overflow-y: auto;
    }

    .lesson-instruction {
      font-size: 1.5rem; font-weight: 900; color: var(--text);
      margin-bottom: 26px; line-height: 1.3;
    }

    .lesson-character-row { display: flex; align-items: flex-start; gap: 14px; margin-bottom: 24px; }
    .lesson-char-avatar { font-size: 3.5rem; line-height: 1; flex-shrink: 0; animation: chickBob 2s ease-in-out infinite; }
    @keyframes chickBob { 0%,100%{ transform:translateY(0); } 50%{ transform:translateY(-6px); } }
    .lesson-speech-bubble {
      background: var(--white); border: 2px solid var(--border);
      border-radius: 16px; border-bottom-left-radius: 4px;
      padding: 14px 18px; position: relative;
      display: flex; align-items: center; gap: 12px;
      cursor: pointer; transition: border-color .15s, box-shadow .15s;
      flex: 1; box-shadow: 0 2px 8px rgba(0,0,0,0.06);
    }
    .lesson-speech-bubble:hover { border-color: var(--blue); box-shadow: 0 4px 16px rgba(28,176,246,0.12); }
    .lesson-speech-bubble::before {
      content: ''; position: absolute; top: 18px; left: -12px;
      border: 6px solid transparent; border-right-color: var(--border);
    }
    .audio-btn-inner {
      width: 38px; height: 38px; border-radius: 50%;
      background: var(--blue); display: flex; align-items: center; justify-content: center;
      flex-shrink: 0; transition: background .15s; box-shadow: 0 3px 0 var(--blue-d);
    }
    .audio-btn-inner svg { width: 18px; height: 18px; fill: white; }
    .lesson-speech-bubble:hover .audio-btn-inner { background: var(--blue-d); }
    .phrase-text { font-size: 1.1rem; font-weight: 700; color: var(--text); line-height: 1.6; }

    .phrase-hint-label {
      font-size: 0.78rem; font-weight: 700; color: var(--text-dim);
      margin-top: -14px; margin-bottom: 20px; padding-left: 6px;
      display: flex; align-items: center; gap: 5px;
    }
    .phrase-hint-label span { color: var(--blue); }
    .phrase-hint-label.hidden-el { display: none; }

    /* ── EJERCICIO: ORDENAR PALABRAS ── */
    .lesson-answer-zone {
      min-height: 56px; border-bottom: 2px solid var(--border2);
      border-top: 2px solid var(--border2);
      padding: 12px 4px; display: flex; flex-wrap: wrap; gap: 8px;
      align-items: flex-start; margin-bottom: 24px; align-content: flex-start;
    }
    .answer-word {
      background: var(--white); border: 2px solid var(--border2);
      border-bottom: 4px solid var(--border);
      color: var(--text); padding: 8px 16px; border-radius: 10px;
      font-family: var(--font); font-size: 0.95rem; font-weight: 700;
      cursor: grab; transition: transform .12s, border-color .15s, box-shadow .1s;
      user-select: none; box-shadow: 0 2px 4px rgba(0,0,0,0.06);
    }
    .answer-word:hover { transform: translateY(-2px); border-color: var(--blue); box-shadow: 0 4px 8px rgba(28,176,246,0.12); }
    .answer-word:active { transform: translateY(2px); border-bottom-width: 2px; cursor: grabbing; }
    .answer-word.dragging { opacity: 0.35; }

    .lesson-wordbank { display: flex; flex-wrap: wrap; gap: 8px; padding-bottom: 16px; align-items: flex-start; }
    .bank-word {
      background: var(--white); border: 2px solid var(--border2);
      border-bottom: 4px solid var(--border);
      color: var(--text); padding: 8px 16px; border-radius: 10px;
      font-family: var(--font); font-size: 0.95rem; font-weight: 700;
      cursor: pointer; transition: transform .1s, opacity .15s, border-color .15s, box-shadow .1s;
      user-select: none; box-shadow: 0 2px 4px rgba(0,0,0,0.06);
    }
    .bank-word:hover { transform: translateY(-2px); box-shadow: 0 4px 8px rgba(0,0,0,0.1); }
    .bank-word:active { transform: translateY(2px); border-bottom-width: 2px; }
    .bank-word.used { opacity: 0.2; pointer-events: none; }
    .drag-hint { font-size: 0.75rem; color: var(--text-dim); font-weight: 700; margin: -14px 0 16px; }

    /* ── EJERCICIO: OPCIÓN MÚLTIPLE ── */
    .choice-list { display: flex; flex-direction: column; gap: 12px; }
    .choice-option {
      background: var(--white); border: 2px solid var(--border2);
      border-bottom: 4px solid var(--border);
      border-radius: 14px; padding: 16px 20px; text-align: left;
      font-family: var(--font); font-size: 1.02rem; font-weight: 700; color: var(--text);
      cursor: pointer; transition: transform .12s, border-color .15s, background .15s;
    }
    .choice-option:hover { border-color: var(--blue); transform: translateY(-2px); }
    .choice-option.selected { border-color: var(--blue); background: #e6f7ff; }
    .choice-option:active { transform: translateY(2px); }

    /* ── EJERCICIO: VERDADERO/FALSO ── */
    .boolean-statement {
      background: var(--bg3); border: 2px solid var(--border); border-radius: 16px;
      padding: 24px; font-size: 1.15rem; font-weight: 800; text-align: center;
      margin-bottom: 22px; line-height: 1.4;
    }
    .boolean-buttons { display: flex; gap: 14px; }
    .boolean-btn {
      flex: 1; padding: 18px; border-radius: 14px; border: 2px solid var(--border2);
      border-bottom: 4px solid var(--border);
      background: var(--white); font-family: var(--font); font-weight: 900; font-size: 1.05rem;
      color: var(--text); cursor: pointer; transition: transform .12s, border-color .15s, background .15s;
    }
    .boolean-btn:hover { transform: translateY(-2px); }
    .boolean-btn.selected.true-opt { border-color: var(--green); background: var(--green-bg); color: var(--green-d); }
    .boolean-btn.selected.false-opt { border-color: var(--red); background: var(--red-bg); color: var(--red-d); }

    /* ── EJERCICIO: COMPLETAR ESPACIO ── */
    .blank-sentence {
      font-size: 1.25rem; font-weight: 800; line-height: 1.8; margin-bottom: 26px;
    }
    .blank-slot {
      display: inline-flex; align-items: center; justify-content: center;
      min-width: 90px; height: 38px; padding: 0 10px;
      border-bottom: 3px solid var(--blue); border-radius: 6px;
      background: #e6f7ff; color: var(--blue-d); font-weight: 900;
      margin: 0 4px; vertical-align: middle; cursor: pointer;
    }
    .blank-slot.filled { background: var(--white); border-bottom-color: var(--text); color: var(--text); }
    .blank-options { display: flex; flex-wrap: wrap; gap: 10px; }

    /* ── BOTONES INFERIORES ── */
    .lesson-bottom {
      position: fixed; bottom: 0; left: 0; right: 0;
      background: var(--white); border-top: 2px solid var(--border);
      padding: 16px 24px; z-index: 50;
    }
    .lesson-bottom-inner {
      max-width: 600px; margin: 0 auto;
      display: flex; align-items: center; justify-content: space-between; gap: 16px;
    }
    .btn-skip {
      background: none; border: 2px solid var(--border2);
      color: var(--text-mid); font-family: var(--font); font-weight: 800;
      font-size: 0.95rem; padding: 14px 28px; border-radius: 14px;
      cursor: pointer; transition: border-color .15s, color .15s;
    }
    .btn-skip:hover { border-color: var(--text-mid); color: var(--text); }
    .btn-check {
      flex: 1; background: var(--border); color: var(--locked-txt);
      border: none; font-family: var(--font); font-weight: 900;
      font-size: 1rem; padding: 16px 32px; border-radius: 14px;
      cursor: not-allowed;
      transition: background .2s, color .2s, box-shadow .15s, transform .15s;
      letter-spacing: 0.4px; text-transform: uppercase;
    }
    .btn-check.ready { background: var(--green); color: var(--white); box-shadow: 0 5px 0 var(--green-d); cursor: pointer; }
    .btn-check.ready:hover { transform: translateY(-2px); box-shadow: 0 7px 0 var(--green-d); }
    .btn-check.ready:active { transform: translateY(3px); box-shadow: 0 2px 0 var(--green-d); }
    .btn-check.wrong { background: var(--red); color: var(--white); box-shadow: 0 5px 0 var(--red-d); cursor: pointer; }
    .btn-check.wrong:hover { transform: translateY(-2px); }
    .btn-check.correct-continue { background: var(--green); color: var(--white); box-shadow: 0 5px 0 var(--green-d); cursor: pointer; }
    .btn-check.correct-continue:hover { transform: translateY(-2px); }

    /* ── FEEDBACK BANNER ── */
    .lesson-feedback {
      position: fixed; bottom: 0; left: 0; right: 0;
      padding: 18px 24px 100px; z-index: 45; display: none;
    }
    .lesson-feedback.correct { background: var(--green-bg); border-top: 2px solid var(--green); display: block; }
    .lesson-feedback.wrong   { background: var(--red-bg);   border-top: 2px solid var(--red);   display: block; }
    .feedback-inner { max-width: 600px; margin: 0 auto; display: flex; align-items: center; gap: 14px; }
    .feedback-icon { font-size: 2rem; animation: feedbackPop .35s cubic-bezier(.34,1.56,.64,1); }
    @keyframes feedbackPop { 0%{ transform:scale(0);} 100%{ transform:scale(1);} }
    .feedback-title { font-size: 1.1rem; font-weight: 900; margin-bottom: 4px; }
    .feedback-title.correct { color: var(--green-d); }
    .feedback-title.wrong { color: var(--red-d); }
    .feedback-answer { font-size: 0.9rem; font-weight: 700; color: var(--text-mid); }

    /* ── TOAST ── */
    .toast {
      position: fixed; bottom: 100px; left: 50%;
      transform: translateX(-50%) translateY(24px);
      background: var(--text); color: var(--white);
      padding: 13px 28px; border-radius: 14px; border: 2px solid rgba(255,255,255,0.1);
      font-size: 0.92rem; font-weight: 700;
      box-shadow: 0 8px 24px rgba(0,0,0,0.15);
      opacity: 0; pointer-events: none;
      transition: opacity .25s, transform .25s; z-index: 999;
      white-space: nowrap;
    }
    .toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }
    .toast.success { background: var(--green-d); }

    /* ── XP FLOAT ── */
    @keyframes xpPop {
      0%  { opacity:0; transform:translate(-50%,-50%) scale(0.6); }
      30% { opacity:1; transform:translate(-50%,-60%) scale(1.1); }
      70% { opacity:1; transform:translate(-50%,-75%) scale(1); }
      100%{ opacity:0; transform:translate(-50%,-95%) scale(0.9); }
    }
    .xp-float {
      position:fixed; left:50%; top:50%; transform:translate(-50%,-50%);
      background:var(--green); color:var(--white);
      font-family:var(--font); font-weight:900; font-size:1.1rem;
      padding:10px 26px; border-radius:14px; pointer-events:none; z-index:9999;
      box-shadow:0 4px 0 var(--green-d);
      animation:xpPop 0.95s ease forwards;
    }

    /* ── COMPLETION MODAL ── */
    .completion-modal {
      position: fixed; inset: 0; background: rgba(0,0,0,0.35);
      z-index: 800; display: flex; align-items: center; justify-content: center;
      padding: 20px; opacity: 0; pointer-events: none; transition: opacity .3s;
    }
    .completion-modal.open { opacity: 1; pointer-events: auto; }
    .completion-card {
      background: var(--white); border: 2px solid var(--border);
      border-radius: 28px; padding: 40px 32px; max-width: 400px; width: 100%;
      text-align: center; transform: scale(0.9);
      transition: transform .35s cubic-bezier(.34,1.56,.64,1);
      box-shadow: 0 20px 60px rgba(0,0,0,0.12);
    }
    .completion-modal.open .completion-card { transform: scale(1); }
    .completion-chick { font-size: 5rem; margin-bottom: 16px; animation: chickBob 2s ease-in-out infinite; }
    .completion-title { font-size: 1.8rem; font-weight: 900; color: var(--yellow); margin-bottom: 8px; }
    .completion-sub { font-size: 1rem; font-weight: 700; color: var(--text-mid); margin-bottom: 26px; line-height: 1.5; }
    .completion-stats { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-bottom: 28px; }
    .stat-box {
      background: var(--bg3); border: 2px solid var(--border);
      border-radius: 14px; padding: 12px 10px; text-align: center;
    }
    .stat-value { font-size: 1.25rem; font-weight: 900; color: var(--yellow); }
    .stat-label { font-size: 0.68rem; font-weight: 800; color: var(--text-mid); text-transform: uppercase; letter-spacing: 0.6px; margin-top: 2px; }
    .completion-btn {
      width: 100%; background: var(--yellow); color: var(--white);
      border: none; font-family: var(--font); font-weight: 900; font-size: 1rem;
      padding: 16px; border-radius: 14px; box-shadow: 0 5px 0 var(--yellow-d);
      cursor: pointer; text-transform: uppercase; letter-spacing: 0.5px;
      transition: transform .15s, box-shadow .15s;
    }
    .completion-btn:hover { transform: translateY(-2px); box-shadow: 0 7px 0 var(--yellow-d); }

    /* ── LOSE MODAL ── */
    .lose-modal {
      position: fixed; inset: 0; background: rgba(0,0,0,0.4);
      z-index: 810; display: flex; align-items: center; justify-content: center;
      padding: 20px; opacity: 0; pointer-events: none; transition: opacity .3s;
    }
    .lose-modal.open { opacity: 1; pointer-events: auto; }
    .lose-card {
      background: var(--white); border-radius: 28px; padding: 40px 32px;
      max-width: 380px; width: 100%; text-align: center;
      transform: scale(0.9); transition: transform .35s cubic-bezier(.34,1.56,.64,1);
      box-shadow: 0 20px 60px rgba(0,0,0,0.15);
    }
    .lose-modal.open .lose-card { transform: scale(1); }
    .lose-chick { font-size: 4.5rem; margin-bottom: 14px; }
    .lose-title { font-size: 1.6rem; font-weight: 900; color: var(--red-d); margin-bottom: 10px; }
    .lose-sub { font-size: 0.95rem; font-weight: 600; color: var(--text-mid); margin-bottom: 24px; line-height: 1.5; }
    .lose-btn {
      width: 100%; background: var(--red); color: var(--white); border: none;
      font-family: var(--font); font-weight: 900; font-size: 1rem;
      padding: 15px; border-radius: 14px; box-shadow: 0 5px 0 var(--red-d);
      cursor: pointer; margin-bottom: 12px; transition: transform .15s;
    }
    .lose-btn:hover { transform: translateY(-2px); }
    .lose-btn-secondary {
      width: 100%; background: none; border: none; color: var(--text-dim);
      font-family: var(--font); font-weight: 700; font-size: 0.9rem; padding: 8px;
      cursor: pointer; text-decoration: underline;
    }

    /* ── FOOTER (sin cambios) ── */
    .footer {
      display: flex; flex-direction: column; align-items: center; justify-content: center;
      background: var(--white); padding: 40px 20px; text-align: center;
      border-top: 2px solid var(--border); gap: 12px;
    }
    .footer-logo { width: 48px; height: 48px; object-fit: contain; }
    .footer-title { font-weight: 900; font-size: 1.5rem; color: var(--text); }
    .footer-tagline { color: #9ca3af; font-weight: 600; font-size: 1.05rem; max-width: 400px; line-height: 1.5; }
    .footer-copy { font-size: 0.95rem; color: var(--blue); font-weight: 800; margin-top: 4px; }

    @media (max-width: 600px) {
      .navbar-links { display: none; }
      .level-tab { padding: 12px 16px; font-size: 0.8rem; }
      .tab-badge { display: none; }
      .lesson-instruction { font-size: 1.2rem; }
      .lesson-char-avatar { font-size: 2.8rem; }
      .completion-stats { grid-template-columns: 1fr 1fr; }
      .node-slot[data-pos="0"] .lesson-node,
      .node-slot[data-pos="4"] .lesson-node { transform: translateX(0); }
      .node-slot[data-pos="1"] .lesson-node,
      .node-slot[data-pos="3"] .lesson-node { transform: translateX(42px); }
      .node-slot[data-pos="2"] .lesson-node { transform: translateX(58px); }
      .node-slot[data-pos="5"] .lesson-node,
      .node-slot[data-pos="7"] .lesson-node { transform: translateX(-42px); }
      .node-slot[data-pos="6"] .lesson-node { transform: translateX(-58px); }
    }

    /* Menú Móvil y Ajustes de Pantalla Pequeña */
    @media (max-width: 768px) {
      .navbar-links, .navbar-auth { display: none; }
      .hamburger {
        display: flex; flex-direction: column; justify-content: space-between;
        width: 28px; height: 20px; background: none; border: none; cursor: pointer;
      }
      .hamburger span { display: block; width: 100%; height: 3px; background-color: var(--text); border-radius: 4px; }
      .nav-menu {
        position: fixed; top: 68px; left: -100%; width: 100%; height: calc(100vh - 68px);
        background-color: var(--white); display: flex; flex-direction: column;
        padding: 32px 24px; transition: left 0.3s ease; z-index: 150; overflow-y: auto;
      }
      .nav-menu.active { left: 0; }
      .nav-menu .navbar-links, .nav-menu .navbar-auth { display: flex; }
      .nav-menu .navbar-links { flex-direction: column; gap: 12px; position: static; transform: none; width: 100%; }
      .nav-menu .navbar-links a { font-size: 1.1rem; padding: 14px 20px; }
      .nav-menu .navbar-links a.active { background: #dbeafe; color: var(--blue); }
      .nav-menu .navbar-auth { flex-direction: column; margin-top: 40px; border-top: 1px solid var(--border); padding-top: 24px; gap: 16px; width: 100%; }
      .nav-menu .btn-entrar { text-align: center; width: 100%; font-size: 1.1rem; }
      .nav-menu .btn-registrarse { text-align: center; width: 100%; padding: 14px 22px; border-radius: 16px; font-size: 1.1rem; }
      .level-tab { padding: 12px 16px; font-size: 0.8rem; }
      .tab-badge { display: none; }
      .lesson-instruction { font-size: 1.2rem; }
      .lesson-char-avatar { font-size: 2.8rem; }
    }

    @media (min-width: 769px) {
      .hamburger { display: none; }
      .nav-menu { display: contents; }
    }