:root{
  --green:#0b6b3d; --green-d:#08442a; --green-l:#e6f2eb; --gold:#f2b316; --gold-l:#fff6dc;
  --ink:#1c2a23; --muted:#5f6f67; --line:#d9e3dd; --bg:#f3f6f4; --card:#fff;
  --good:#1f7a4c; --bad:#b0413e; --warn:#9b5d18; --radius:14px;
  --shadow:0 2px 10px rgba(8,68,42,.06);
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;font-family:"Segoe UI",system-ui,-apple-system,Arial,sans-serif;color:var(--ink);background:var(--bg);line-height:1.55}
a{color:var(--green)}
button,input,select,textarea{font:inherit}
button{cursor:pointer}
:focus-visible{outline:3px solid #6fb08b;outline-offset:2px}

/* Top bar */
.topbar{background:var(--green-d);color:#fff}
.topbar-in{max-width:1100px;margin:auto;padding:10px 16px;display:flex;align-items:center;gap:14px;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:10px;color:#fff;text-decoration:none;font-weight:700;letter-spacing:.01em}
.brand img{width:30px;height:30px}
.brand small{display:block;font-weight:500;opacity:.75;font-size:.75rem;letter-spacing:.06em;text-transform:uppercase}
.topbar .spacer{flex:1}
.topbar .who{font-size:.85rem;opacity:.85;overflow-wrap:anywhere}
.topbar a.btn-ghost{color:#fff;border:1px solid rgba(255,255,255,.35);padding:6px 12px;border-radius:999px;text-decoration:none;font-size:.85rem}
.topbar a.btn-ghost:hover{background:rgba(255,255,255,.1)}
.preview-banner{background:var(--gold);color:#3b2a00;text-align:center;font-size:.85rem;padding:6px 12px;font-weight:600}
.preview-banner a{color:#3b2a00}

/* Layout */
.wrap{max-width:1100px;margin:auto;padding:22px 16px 60px}
.narrow{max-width:820px}
.hero{background:linear-gradient(135deg,var(--green-d),var(--green));color:#fff;padding:34px 16px 30px;position:relative;overflow:hidden}
.hero::after{content:"";position:absolute;right:-60px;top:-60px;width:240px;height:240px;border-radius:50%;background:rgba(242,179,22,.18)}
.hero-in{max-width:1100px;margin:auto;position:relative;z-index:1}
.kicker{font-size:.78rem;letter-spacing:.12em;text-transform:uppercase;font-weight:700;opacity:.85}
.hero h1{margin:.25rem 0 .35rem;font-size:clamp(1.8rem,4.6vw,2.8rem);line-height:1.15}
.hero p{max-width:760px;margin:.3rem 0 0;opacity:.95}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:22px;box-shadow:var(--shadow)}
.card + .card{margin-top:18px}
h2{color:var(--green-d);line-height:1.25}
.label{display:inline-block;font-size:.72rem;text-transform:uppercase;letter-spacing:.09em;font-weight:700;color:var(--muted)}

/* Article */
.article{font-size:1.04rem}
.article h2{margin-top:.2rem}
.article p{margin:.9rem 0}
.reminder{margin-top:18px;background:var(--gold-l);border-left:5px solid var(--gold);padding:14px 16px;border-radius:8px}
.section-title{display:flex;align-items:center;gap:10px;margin:30px 0 12px}
.section-title .num{width:30px;height:30px;border-radius:50%;background:var(--green);color:#fff;display:grid;place-items:center;font-weight:700;font-size:.9rem;flex:none}
.section-title h2{margin:0;font-size:1.35rem}

/* Buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;border:0;border-radius:10px;background:var(--green);color:#fff;padding:11px 18px;font-weight:700;text-decoration:none}
.btn:hover{background:var(--green-d)}
.btn.secondary{background:#fff;color:var(--green-d);border:1px solid var(--line)}
.btn.secondary:hover{background:var(--green-l)}
.btn.small{padding:7px 12px;font-size:.85rem;border-radius:8px}
.btn:disabled{opacity:.55;cursor:not-allowed}

/* Forms */
.field{display:block;margin:0 0 14px}
.field span{display:block;font-weight:600;margin-bottom:6px;font-size:.92rem}
.input{width:100%;padding:12px 13px;border:1px solid #c5d3ca;border-radius:10px;background:#fff;color:var(--ink)}
.input:focus{border-color:var(--green);outline:none;box-shadow:0 0 0 3px rgba(11,107,61,.15)}
.error{color:var(--bad);font-weight:600;min-height:1.3em;margin:6px 0 0}

/* Done banner */
.done{display:none;margin-top:18px;background:#e7f3eb;border:1px solid #b9d9c5;border-radius:var(--radius);padding:20px}
.done.show{display:block}
.done h2{margin:.2rem 0 .4rem}

/* Learning point / answer key */
#key-slot:empty{display:none}
#key-slot{margin-top:26px}
.keybox{background:#fff;border:2px solid var(--gold);border-radius:var(--radius);padding:20px}
.keybox h2{margin-top:.2rem}
.keybox table{width:100%;border-collapse:collapse;font-size:.94rem}
.keybox th,.keybox td{text-align:left;vertical-align:top;border-bottom:1px solid var(--line);padding:8px}

.status-pill{display:inline-block;padding:3px 10px;border-radius:999px;font-size:.78rem;font-weight:700}
.st-none{background:#eef1ef;color:var(--muted)}
.st-view{background:#e8f0fb;color:#2d5b8c}
.st-start{background:var(--gold-l);color:#7a5200}
.st-done{background:var(--green-l);color:var(--good)}

footer.site{text-align:center;color:var(--muted);font-size:.8rem;padding:20px 16px 30px}

@media(max-width:640px){
  .card{padding:17px}
  .topbar .who{display:none}
}