:root { --bg:#0f172a; --card:#111827; --ink:#e5e7eb; --muted:#9ca3af; --accent:#22c55e; --danger:#ef4444; }
*{box-sizing:border-box} html,body{margin:0;padding:0}
body{font-family:system-ui,-apple-system,Segoe UI,Roboto,Ubuntu,sans-serif;background:var(--bg);color:var(--ink);line-height:1.5}
.app-header,.app-footer{display:flex;justify-content:space-between;align-items:center;padding:12px 16px;background:#0b1224;position:sticky;top:0;z-index:10}
h1{font-size:1.25rem;margin:0} h2{margin:0 0 .75rem 0}
main{max-width:900px;margin:16px auto;padding:0 16px}
.view{display:block} .view[hidden]{display:none}
.card{background:var(--card);border:1px solid #1f2937;border-radius:14px;padding:16px;box-shadow:0 6px 20px rgba(0,0,0,.25)}
.card-list{display:grid;gap:12px}
.card .meta{color:var(--muted);font-size:.9rem}
.btn{appearance:none;border:1px solid #2a3446;background:#151b2c;color:var(--ink);padding:10px 14px;border-radius:10px;cursor:pointer}
.btn.primary{background:var(--accent);border-color:var(--accent);color:#05210f;font-weight:600}
.btn.ghost{background:transparent;border-color:#2a3446}
.btn[disabled]{opacity:.5;cursor:not-allowed}
nav .btn{margin-left:8px}
.quiz-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:12px}
.badge{display:inline-block;background:#172554;border:1px solid #1e3a8a;color:#c7d2fe;padding:.15rem .5rem;border-radius:999px;font-size:.75rem}
.choice{display:block;margin:.5rem 0;padding:.5rem .75rem;border:1px solid #334155;border-radius:8px;cursor:pointer}
.choice input{margin-right:.5rem}
.feedback{margin-top:.5rem;font-size:.9rem}
.correct{color:var(--accent)} .incorrect{color:var(--danger)}
.actions,.quiz-actions{display:flex;gap:8px;margin-top:12px}
input[type="text"]{width:100%;padding:.6rem .75rem;border-radius:8px;border:1px solid #334155;background:#0b1224;color:var(--ink)}
small, .muted{color:var(--muted)}