:root{
    --bg:#f4f6fb; --card:#ffffff; --soft:#f0f3f9; --line:#e3e8f0;
    --txt:#1e293b; --mut:#64748b;
    --accent:#2563eb; --accent2:#7c3aed;
    --green:#16a34a; --yellow:#d97706; --orange:#ea580c; --red:#dc2626; --purple:#7c3aed;
    --radius:16px; --shadow:0 1px 3px rgba(15,23,42,.06),0 8px 24px rgba(15,23,42,.04);
  }
  *{box-sizing:border-box;margin:0;padding:0}
  html{scroll-behavior:smooth}
  body{
    font-family:'Segoe UI',system-ui,-apple-system,sans-serif;
    background:var(--bg);color:var(--txt);line-height:1.6;
    background-image:radial-gradient(circle at 12% 0%,rgba(124,58,237,.07),transparent 38%),radial-gradient(circle at 88% 6%,rgba(37,99,235,.07),transparent 38%);
    background-attachment:fixed;
  }
  code{background:var(--soft);padding:1px 6px;border-radius:5px;font-size:.92em;color:var(--accent2)}

  /* ===== TOP BAR ===== */
  #topbar{position:fixed;top:0;left:0;right:0;z-index:100;background:rgba(255,255,255,.8);backdrop-filter:blur(12px);border-bottom:1px solid var(--line)}
  #topbar .inner{max-width:920px;margin:0 auto;padding:11px 20px;display:flex;align-items:center;gap:14px}
  #topbar .logo{font-weight:800;font-size:15px;white-space:nowrap}
  #topbar .logo span{color:var(--accent)}
  .progwrap{flex:1;height:9px;background:var(--soft);border-radius:99px;overflow:hidden}
  .progbar{height:100%;width:0;background:linear-gradient(90deg,var(--accent),var(--accent2));border-radius:99px;transition:width .4s ease}
  #progpct{font-size:13px;color:var(--mut);font-weight:600;font-variant-numeric:tabular-nums;min-width:38px;text-align:right}
  #saveDot{font-size:11px;color:var(--mut);white-space:nowrap;display:flex;align-items:center;gap:5px}
  #saveDot b{width:8px;height:8px;border-radius:99px;background:#cbd5e1;display:inline-block;transition:.3s}
  #saveDot.ok b{background:var(--green)}
  #saveDot.busy b{background:var(--yellow)}

  /* ===== HERO ===== */
  .hero{max-width:760px;margin:0 auto;padding:118px 20px 30px;text-align:center}
  .hero .badge{display:inline-block;background:#fff;border:1px solid var(--line);color:var(--accent);padding:6px 14px;border-radius:99px;font-size:12.5px;font-weight:700;letter-spacing:.3px;margin-bottom:22px;box-shadow:var(--shadow)}
  .hero h1{font-size:clamp(30px,5.5vw,46px);line-height:1.08;letter-spacing:-1px;margin-bottom:14px;color:#0f172a}
  .hero h1 em{font-style:normal;background:linear-gradient(120deg,var(--accent),var(--accent2));-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent}
  .hero p.sub{font-size:17px;color:var(--mut);max-width:560px;margin:0 auto 26px}
  .name-gate{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:22px;max-width:440px;margin:0 auto}
  .name-gate label{display:block;text-align:left;font-size:13px;font-weight:700;color:var(--mut);margin-bottom:8px}
  .name-gate .row{display:flex;gap:10px}
  .name-gate input{flex:1;background:var(--soft);border:1px solid var(--line);color:var(--txt);padding:13px 16px;border-radius:11px;font-size:15px}
  .name-gate input:focus{outline:none;border-color:var(--accent);background:#fff}
  .name-gate button{background:linear-gradient(120deg,var(--accent),var(--accent2));color:#fff;border:none;padding:0 22px;border-radius:11px;font-size:15px;font-weight:700;cursor:pointer;white-space:nowrap}
  .who{display:none;align-items:center;justify-content:center;gap:10px;background:var(--card);border:1px solid var(--line);border-radius:99px;box-shadow:var(--shadow);padding:8px 8px 8px 18px;max-width:fit-content;margin:0 auto}
  .who b{color:var(--accent)} .who button{background:var(--soft);border:1px solid var(--line);color:var(--mut);padding:6px 12px;border-radius:99px;font-size:12px;cursor:pointer}

  /* ===== MAIN ===== */
  main{max-width:920px;margin:0 auto;padding:14px 20px 20px;filter:blur(0);transition:.4s}
  main.locked{filter:blur(6px);pointer-events:none;opacity:.55}

  .callout{border-radius:var(--radius);padding:16px 20px;margin:22px 0;border-left:4px solid;display:flex;gap:13px;align-items:flex-start;font-size:14.5px;background:var(--card);box-shadow:var(--shadow)}
  .callout .ico{font-size:22px;line-height:1}
  .callout.warn{border-color:var(--yellow);background:#fffbeb}
  .callout.danger{border-color:var(--red);background:#fef2f2}
  .callout.tip{border-color:var(--accent);background:#eff6ff}

  /* ===== LEVEL ACCORDION ===== */
  .level{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);margin:16px 0;overflow:hidden;box-shadow:var(--shadow)}
  .level-head{padding:18px 22px;display:flex;align-items:center;gap:15px;cursor:pointer;user-select:none}
  .level-head:hover{background:var(--soft)}
  .level-dot{width:42px;height:42px;border-radius:12px;display:grid;place-items:center;font-size:19px;flex-shrink:0;font-weight:800}
  .level-meta{flex:1;min-width:0}
  .level-meta h2{font-size:18px;letter-spacing:-.3px}
  .level-meta p{font-size:13px;color:var(--mut)}
  .level-count{font-size:12px;color:var(--mut);background:var(--soft);padding:4px 11px;border-radius:99px;white-space:nowrap;font-weight:600}
  .chev{transition:.3s;color:var(--mut);font-size:12px}
  .level.open .chev{transform:rotate(180deg)}
  .level-body{max-height:0;overflow:hidden;transition:max-height .5s ease}
  .level.open .level-body{max-height:none}
  .level-inner{padding:2px 22px 22px}

  .l0 .level-dot{background:#eff6ff;color:var(--accent)}
  .l1 .level-dot{background:#f0fdf4;color:var(--green)}
  .l2 .level-dot{background:#fffbeb;color:var(--yellow)}
  .l3 .level-dot{background:#fff7ed;color:var(--orange)}
  .l4 .level-dot{background:#fef2f2;color:var(--red)}
  .l5 .level-dot{background:#faf5ff;color:var(--purple)}

  /* ===== EXERCISE ===== */
  .ex{border-top:1px solid var(--line);padding:20px 0}
  .ex:first-child{border-top:none}
  .ex-head{display:flex;align-items:flex-start;gap:12px;margin-bottom:12px}
  .ex-check{appearance:none;width:24px;height:24px;border:2px solid var(--line);border-radius:7px;cursor:pointer;flex-shrink:0;margin-top:1px;position:relative;transition:.2s;background:#fff}
  .ex-check:checked{background:var(--green);border-color:var(--green)}
  .ex-check:checked::after{content:'✓';position:absolute;color:#fff;font-size:15px;font-weight:700;top:-2px;left:4px}
  .ex-title{font-size:16px;font-weight:700}
  .ex-title small{display:block;color:var(--mut);font-weight:500;font-size:13px;margin-top:1px}

  .prompt-box{background:#0f172a;border-radius:11px;padding:11px 13px;margin:9px 0;display:flex;align-items:center;gap:12px;font-family:'SF Mono',ui-monospace,monospace;font-size:13.5px;color:#bae0ff}
  .prompt-box .ptxt{flex:1}
  .prompt-box .ptag{color:#64748b;font-family:system-ui;font-size:10.5px;font-weight:700;text-transform:uppercase;letter-spacing:.5px;white-space:nowrap}
  .copy{background:rgba(255,255,255,.08);border:1px solid rgba(255,255,255,.15);color:#cbd5e1;padding:6px 11px;border-radius:7px;cursor:pointer;font-size:12px;font-weight:600;transition:.2s;white-space:nowrap}
  .copy:hover{background:rgba(255,255,255,.16);color:#fff}
  .copy.done{color:#4ade80;border-color:#4ade80}

  .q{font-size:14.5px;margin:14px 0 8px}
  .q b{color:var(--accent)}
  textarea{width:100%;background:#fff;border:1px solid var(--line);color:var(--txt);border-radius:11px;padding:12px 14px;font-size:14px;font-family:inherit;resize:vertical;min-height:72px;transition:.2s}
  textarea:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 3px rgba(37,99,235,.1)}

  /* screenshot dropzone — display:block fixes the layout */
  .drop{position:relative;display:block;width:100%;border:2px dashed var(--line);border-radius:12px;padding:22px;text-align:center;color:var(--mut);cursor:pointer;transition:.2s;margin:10px 0;background:var(--soft);font-size:13.5px}
  .drop:hover{border-color:var(--accent);color:var(--accent);background:#eff6ff}
  .drop .ico{font-size:24px;display:block;margin-bottom:6px}
  .drop img{display:block;max-width:100%;border-radius:9px;margin:8px auto 0;box-shadow:var(--shadow)}
  .drop input{display:none}
  .drop:focus{outline:none}
  .drop.active{border-color:var(--accent);background:#eff6ff;box-shadow:0 0 0 3px rgba(37,99,235,.15)}
  .drop.drag{border-color:var(--accent);background:#dbeafe;border-style:solid}
  .drop.filled{border-style:solid;border-color:var(--green);background:#f0fdf4}
  .drop.filled .ico{color:var(--green)}
  .drop .del{display:none;position:absolute;top:8px;right:8px;width:28px;height:28px;border-radius:50%;background:rgba(15,23,42,.72);color:#fff;border:none;cursor:pointer;font-size:17px;line-height:1;z-index:2;transition:.2s}
  .drop.filled .del{display:grid;place-items:center}
  .drop .del:hover{background:var(--red);transform:scale(1.08)}
  .dhint{font-size:11.5px;color:var(--mut);margin-top:7px}
  .dhint kbd{background:#fff;border:1px solid var(--line);border-bottom-width:2px;border-radius:5px;padding:0 5px;font-family:inherit;font-size:11px;color:var(--txt)}
  .dhint .browse{color:var(--accent);cursor:pointer;text-decoration:underline;font-weight:600}
  .drop.active .dhint{color:var(--accent);font-weight:600}
  .drop.filled .dhint{display:none}
  #toast{position:fixed;bottom:24px;left:50%;transform:translateX(-50%) translateY(20px);background:#0f172a;color:#fff;padding:11px 20px;border-radius:11px;font-size:13.5px;box-shadow:0 8px 24px rgba(0,0,0,.25);opacity:0;pointer-events:none;transition:.3s;z-index:200}
  #toast.show{opacity:1;transform:translateX(-50%) translateY(0)}

  .vocab{width:100%;border-collapse:collapse;margin:12px 0;font-size:14px}
  .vocab td{border:1px solid var(--line);padding:0}
  .vocab td.term{background:var(--soft);padding:12px;width:34%;font-family:monospace;color:var(--purple);vertical-align:middle;font-size:13px}
  .vocab td input{width:100%;background:#fff;border:none;color:var(--txt);padding:12px;font-size:14px}
  .vocab td input:focus{outline:none;background:#fafcff}

  .checklist{list-style:none;margin:12px 0}
  .checklist li{display:flex;align-items:center;gap:12px;padding:12px 14px;background:#fff;border:1px solid var(--line);border-radius:11px;margin-bottom:8px;font-size:14.5px}
  .checklist input{appearance:none;width:22px;height:22px;border:2px solid var(--line);border-radius:6px;cursor:pointer;flex-shrink:0;position:relative;transition:.2s;background:#fff}
  .checklist input:checked{background:var(--purple);border-color:var(--purple)}
  .checklist input:checked::after{content:'✓';position:absolute;color:#fff;font-size:13px;top:-2px;left:4px}
  .checklist input:checked + span{color:var(--mut);text-decoration:line-through}

  .acquis{background:#f0fdf4;border:1px solid #bbf7d0;border-radius:11px;padding:12px 16px;margin-top:18px;font-size:14px}
  .acquis b{color:var(--green)}

  .two-col{display:grid;grid-template-columns:1fr 1fr;gap:12px}
  @media(max-width:600px){.two-col{grid-template-columns:1fr}.name-gate .row{flex-direction:column}}

  footer{text-align:center;padding:36px 20px 64px;color:var(--mut);font-size:13px}
  .btn-print{background:#fff;color:var(--accent);border:1px solid var(--line);padding:13px 26px;border-radius:12px;font-size:14.5px;font-weight:700;cursor:pointer;transition:.2s;box-shadow:var(--shadow)}
  .btn-print:hover{border-color:var(--accent)}

  /* navigation entre cahiers */
  .nav-btns{display:flex;justify-content:space-between;align-items:stretch;gap:12px;max-width:920px;margin:0 auto 28px;flex-wrap:wrap}
  .nav-btn{display:inline-flex;flex-direction:column;justify-content:center;text-align:left;background:var(--card);border:1px solid var(--line);color:var(--txt);padding:14px 22px;border-radius:14px;font-size:15px;font-weight:700;cursor:pointer;text-decoration:none;box-shadow:var(--shadow);transition:.2s;min-width:230px}
  .nav-btn:hover{border-color:var(--accent);transform:translateY(-2px)}
  .nav-btn small{font-size:11.5px;font-weight:600;color:var(--mut);text-transform:uppercase;letter-spacing:.4px;margin-bottom:2px}
  .nav-btn.next{margin-left:auto;text-align:right;background:linear-gradient(120deg,var(--accent),var(--accent2));color:#fff;border:none}
  .nav-btn.next small{color:rgba(255,255,255,.8)}
  .nav-btn.next:hover{opacity:.93}
  @media(max-width:600px){.nav-btn{flex:1;min-width:0}}

  @media print{#topbar,footer,.nav-btns{display:none}main{filter:none!important;opacity:1!important}.level-body{max-height:none!important}.level,.ex{break-inside:avoid}body{background:#fff}}