:root{
  --bg:#f5f7fb; --card:#ffffff; --text:#1e2433; --muted:#6b7385;
  --brand:#E11B22; --brand-dark:#B3141A; --ok:#12b76a; --danger:#e5484d;
  --border:#e6e9f0; --radius:14px; --shadow:0 2px 10px rgba(20,30,60,.06);
}
*{box-sizing:border-box}
body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  background:var(--bg);color:var(--text);line-height:1.5}
a{color:var(--brand);text-decoration:none}
button{font:inherit;cursor:pointer}
.btn{background:var(--brand);color:#fff;border:0;border-radius:10px;padding:10px 16px;font-weight:600;transition:.15s}
.btn:hover{background:var(--brand-dark)}
.btn.ghost{background:#eef2fb;color:var(--brand)}
.btn.ghost:hover{background:#e2e9fa}
.btn.sm{padding:6px 12px;font-size:.85rem;border-radius:8px}
.btn.danger{background:var(--danger)}
.btn.ok{background:var(--ok)}
input,select,textarea{font:inherit;width:100%;padding:10px 12px;border:1px solid var(--border);
  border-radius:10px;background:#fff;color:var(--text)}
textarea{min-height:120px;resize:vertical}
label{display:block;font-weight:600;font-size:.85rem;margin:12px 0 4px;color:var(--muted)}

/* Topbar */
.topbar{background:var(--card);border-bottom:1px solid var(--border);padding:0 24px;height:60px;
  display:flex;align-items:center;justify-content:space-between;position:sticky;top:0;z-index:10}
.brand{font-weight:800;font-size:1.15rem;display:flex;align-items:center;gap:8px}
.brand .dot{width:12px;height:12px;border-radius:4px;background:var(--brand);display:inline-block}
.topbar .right{display:flex;align-items:center;gap:14px;color:var(--muted);font-size:.9rem}

.wrap{max-width:1080px;margin:0 auto;padding:24px}
.card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);
  box-shadow:var(--shadow);padding:20px;margin-bottom:18px}
.card h2{margin:0 0 4px}
.muted{color:var(--muted)}
.row{display:flex;gap:12px;flex-wrap:wrap;align-items:center}
.grid{display:grid;gap:16px;grid-template-columns:repeat(auto-fill,minmax(260px,1fr))}

/* Tabs */
.tabs{display:flex;gap:6px;margin-bottom:18px;flex-wrap:wrap}
.tabs button{background:transparent;border:1px solid var(--border);border-radius:10px;padding:8px 16px;
  color:var(--muted);font-weight:600}
.tabs button.active{background:var(--brand);color:#fff;border-color:var(--brand)}

/* Table */
table{width:100%;border-collapse:collapse}
th,td{text-align:left;padding:10px 12px;border-bottom:1px solid var(--border);font-size:.92rem}
th{color:var(--muted);font-weight:600;font-size:.8rem;text-transform:uppercase;letter-spacing:.03em}

/* Progress bar */
.bar{height:8px;background:#eef1f7;border-radius:6px;overflow:hidden}
.bar > i{display:block;height:100%;background:var(--ok);border-radius:6px}

/* Login */
.login-page{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:20px}
.login-box{background:var(--card);border:1px solid var(--border);border-radius:18px;box-shadow:var(--shadow);
  padding:34px;width:100%;max-width:380px}
.login-box .brand{justify-content:center;margin-bottom:6px;font-size:1.4rem}

/* Course cards */
.course-card{cursor:pointer;transition:.15s}
.course-card:hover{transform:translateY(-2px);box-shadow:0 8px 22px rgba(20,30,60,.10)}
.pill{display:inline-block;background:#eef2fb;color:var(--brand);border-radius:999px;padding:2px 10px;font-size:.78rem;font-weight:600}

/* Lesson layout */
.lesson-wrap{display:grid;grid-template-columns:280px 1fr;gap:20px}
.lesson-list{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:10px;height:fit-content}
.lesson-list .item{padding:10px 12px;border-radius:10px;cursor:pointer;display:flex;gap:8px;align-items:center;font-size:.92rem}
.lesson-list .item:hover{background:#f2f5fc}
.lesson-list .item.active{background:#eaf0ff;color:var(--brand);font-weight:600}
.check{width:18px;height:18px;border-radius:50%;border:2px solid var(--border);flex:0 0 auto;display:inline-block}
.check.done{background:var(--ok);border-color:var(--ok);position:relative}
.check.done::after{content:"";position:absolute;left:5px;top:2px;width:4px;height:8px;border:solid #fff;border-width:0 2px 2px 0;transform:rotate(45deg)}
.lesson-content{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:26px;min-height:320px}
.lesson-content iframe,.lesson-content video{width:100%;border:0;border-radius:12px;aspect-ratio:16/9}
.lesson-content .prose{max-width:70ch}

.toast{position:fixed;bottom:20px;left:50%;transform:translateX(-50%);background:#1e2433;color:#fff;
  padding:12px 20px;border-radius:10px;font-size:.9rem;opacity:0;transition:.25s;z-index:50}
.toast.show{opacity:1}
.hidden{display:none!important}
.creds{background:#f7faf7;border:1px solid #d6ead9;border-radius:10px;padding:12px;max-height:260px;overflow:auto;font-size:.85rem}
.creds code{background:#eef2fb;padding:1px 5px;border-radius:4px}
@media(max-width:760px){.lesson-wrap{grid-template-columns:1fr}}