:root{
  --orange:#F68920; --teal:#21BDBE; --teal-700:#198E8F; --yellow:#FCBC17;
  --ink:#1f2a30; --gray-700:#4b5a62; --muted:#7c8a92; --line:#e6ecee;
  --bg:#f4f7f8; --card:#ffffff; --success:#1a9d63; --danger:#d64545;
  --sb:188px;
}
*{box-sizing:border-box}
html,body{margin:0;padding:0}
body{font-family:'Prompt',system-ui,sans-serif;color:var(--ink);background:var(--bg);font-size:15px}
button{font-family:inherit}
.hidden{display:none!important}
a{color:inherit}

/* ---------- Login ---------- */
.login-wrap{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:24px;
  background:linear-gradient(135deg,#eaf7f7,#fef6e8)}
.login-card{background:var(--card);border-radius:18px;box-shadow:0 12px 40px rgba(25,142,143,.12);
  padding:34px 30px;width:100%;max-width:380px;text-align:center}
.login-card .logo{display:flex;gap:4px;justify-content:center;margin-bottom:6px}
.login-card h1{font-size:20px;margin:8px 0 2px}
.login-card p.sub{color:var(--muted);font-size:13px;margin:0 0 22px}
.field{text-align:left;margin-bottom:14px}
.field label{display:block;font-size:13px;color:var(--gray-700);margin-bottom:5px}
.field input{width:100%;padding:11px 13px;border:1px solid var(--line);border-radius:10px;font-size:15px;font-family:inherit}
.field input:focus{outline:none;border-color:var(--teal)}
.login-err{color:var(--danger);font-size:13px;margin:-4px 0 12px;min-height:16px}

/* ---------- Buttons ---------- */
.btn{border:none;border-radius:10px;padding:11px 18px;font-size:14px;font-weight:600;cursor:pointer;text-decoration:none;display:inline-block}
.btn-primary{background:var(--orange);color:#fff;width:100%}
.btn-teal{background:var(--teal);color:#fff}
.btn-ghost{background:#eef3f4;color:var(--gray-700)}
.btn:disabled{opacity:.6;cursor:default}

/* ---------- App shell ---------- */
.shell{display:flex;min-height:100vh}
.sidebar{width:var(--sb);background:var(--teal-700);color:#fff;flex-shrink:0;padding:18px 0;position:sticky;top:0;height:100vh}
.sidebar .brand{padding:0 18px 16px;font-weight:700;font-size:15px;display:flex;gap:6px;align-items:center;border-bottom:1px solid rgba(255,255,255,.15)}
.sidebar nav{margin-top:10px}
.sidebar nav a{display:block;padding:11px 20px;color:#dff5f5;font-size:14px;cursor:pointer;border-left:3px solid transparent}
.sidebar nav a.active,.sidebar nav a:hover{background:rgba(255,255,255,.12);border-left-color:var(--yellow);color:#fff}
.main{flex:1;display:flex;flex-direction:column;min-width:0}
.topbar{background:#fff;border-bottom:1px solid var(--line);padding:12px 24px;display:flex;align-items:center;justify-content:space-between}
.topbar .logo{display:flex;gap:3px;align-items:center}
.topbar .who{font-size:13px;color:var(--gray-700)}
.topbar .who b{color:var(--ink)}
.content{padding:26px 30px;max-width:900px;width:100%;margin:0 auto}

/* ---------- Cards ---------- */
.eyebrow{color:var(--teal-700);font-weight:700;font-size:12px;letter-spacing:.04em;text-transform:uppercase}
.card{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:20px 22px;margin-bottom:16px}
.muted{color:var(--muted);font-size:13px}
h1{font-size:22px;margin:4px 0 12px}
h2{font-size:17px;margin:0 0 12px}
.grid{display:grid;grid-template-columns:1fr 1fr;gap:14px}
@media(max-width:640px){.grid{grid-template-columns:1fr}.sidebar{display:none}}
.tile{background:#fff;border:1px solid var(--line);border-radius:14px;padding:16px 18px;cursor:pointer;transition:.15s}
.tile:hover{border-color:var(--teal);box-shadow:0 6px 18px rgba(33,189,190,.10)}
.tile .k{font-size:12px;color:var(--teal-700);font-weight:700}
.tile .t{font-weight:600;margin:4px 0}
.tile .m{font-size:12px;color:var(--muted)}
.section-title{font-weight:700;color:var(--gray-700);margin:18px 0 8px;font-size:14px}

/* ---------- Lesson ---------- */
.vwrap{position:relative;padding-top:56.25%;background:#0d1b1e;border-radius:12px;overflow:hidden;margin:12px 0}
.vwrap iframe{position:absolute;inset:0;width:100%;height:100%;border:0}
.lessontext{background:#fff;border:1px solid var(--line);border-radius:12px;padding:16px 18px;margin:12px 0;line-height:1.7}
.lcheck{background:#f0faf9;border:1px solid #d3f0f0;border-radius:12px;padding:16px 18px;margin:14px 0}

/* ---------- Options ---------- */
.opt{display:flex;gap:10px;align-items:center;padding:11px 14px;border:1px solid var(--line);border-radius:10px;margin:8px 0;cursor:pointer;background:#fff}
.opt:hover{border-color:var(--teal)}
.opt.sel{border-color:var(--teal);background:#edf9f9}
.opt.ok{border-color:var(--success);background:#e9f7ef}
.opt.bad{border-color:var(--danger);background:#fbeaea}
.opt .dot{width:16px;height:16px;border-radius:50%;border:2px solid #c4d2d6;flex-shrink:0}
.opt.sel .dot{border-color:var(--teal);background:var(--teal)}
.q{background:#fff;border:1px solid var(--line);border-radius:14px;padding:20px 22px;margin-bottom:14px}

/* ---------- Tags / status ---------- */
.tag{display:inline-block;padding:4px 12px;border-radius:999px;font-size:13px;font-weight:600;margin:6px 0}
.tag.pass{background:#e9f7ef;color:var(--success)}
.tag.fail{background:#fbeaea;color:var(--danger)}
.st{display:inline-block;padding:2px 9px;border-radius:999px;font-size:12px;font-weight:600}
.st.ok{background:#e9f7ef;color:var(--success)}
.timer{font-weight:700;color:var(--teal-700);background:#edf9f9;border:1px solid #d3f0f0;border-radius:999px;padding:5px 14px}
.timer.warn{color:var(--danger)}
.rowbtns{display:flex;justify-content:space-between;gap:10px}