:root { --green:#0b3d2e; --green2:#14532d; --gold:#d4a537; --bg:#f4f6f4; --blue:#0b5394; }
* { box-sizing:border-box; }
body { font-family:-apple-system,'Segoe UI',Roboto,sans-serif; margin:0; background:var(--bg); color:#1a1a1a; line-height:1.6; }
header { background:var(--green); color:#fff; padding:26px 20px 22px; }
header .inner { max-width:820px; margin:0 auto; }
header .k { letter-spacing:3px; font-size:11px; color:var(--gold); }
header h1 { margin:6px 0 4px; font-size:24px; }
header p { margin:2px 0; color:#d9e5de; font-size:14px; }
header a { color:var(--gold); text-decoration:none; }
main { max-width:820px; margin:0 auto; padding:18px 14px 70px; }
h2 { color:var(--green); border-bottom:3px solid var(--green); padding-bottom:6px; margin:30px 0 12px; font-size:20px; }
h3 { color:var(--green2); margin:20px 0 8px; font-size:16.5px; }
.badge { display:inline-block; background:var(--gold); color:#1a1a1a; font-size:11.5px; font-weight:700; padding:2px 9px; border-radius:4px; margin-left:6px; vertical-align:middle; }
.obj { background:#eef4f0; border-left:4px solid var(--green); padding:10px 14px; border-radius:6px; font-size:14.5px; margin:14px 0; }
.warn { background:#fdf1f1; border-left:4px solid #b02a2a; padding:10px 14px; border-radius:6px; font-size:14px; margin:14px 0; }
.quote { background:#fdf6e3; border-left:4px solid var(--gold); padding:10px 14px; border-radius:6px; font-style:italic; font-size:14.5px; margin:12px 0; }
.quote .src { display:block; font-style:normal; font-size:12px; color:#777; margin-top:4px; }
.video-box { margin:14px 0; }
.video-box iframe { width:100%; aspect-ratio:16/9; border:0; border-radius:10px; background:#000; }
.video-box video { width:100%; max-height:430px; border-radius:10px; background:#000; }
.video-box .cap { font-size:13px; color:#555; margin-top:4px; }
.qcard { background:#fff; border:1px solid #cfd9d2; border-radius:12px; padding:14px 16px; margin:14px 0; box-shadow:0 1px 4px rgba(0,0,0,.05); }
.qcard .qnum { color:var(--gold); font-weight:800; font-size:12px; letter-spacing:1px; }
.qcard p.q { font-weight:600; margin:6px 0 8px; }
textarea { width:100%; min-height:88px; border:1.5px solid #b9c8bf; border-radius:8px; padding:9px 11px; font:inherit; font-size:14px; resize:vertical; background:#fbfdfb; }
textarea:focus { outline:2px solid var(--green); }
.btn { display:inline-block; background:var(--green); color:#fff; font-weight:700; padding:9px 16px; border-radius:8px; border:0; cursor:pointer; font-size:14px; margin:8px 6px 0 0; }
.btn.gold { background:var(--gold); color:#1a1a1a; }
.btn.ghost { background:#e6ede8; color:var(--green); }
.btn:disabled { opacity:.45; cursor:default; }
.reveal { display:none; background:#eef4f0; border:1.5px dashed var(--green); border-radius:8px; padding:11px 13px; margin-top:10px; font-size:14.5px; }
.reveal.open { display:block; }
.selfgrade { display:none; margin-top:8px; font-size:13.5px; }
.selfgrade.open { display:block; }
.selfgrade button { border:1.5px solid #b9c8bf; background:#fff; border-radius:7px; padding:5px 11px; margin-right:6px; cursor:pointer; font-size:13px; }
.selfgrade button.sel { background:var(--green); color:#fff; border-color:var(--green); }
.mcq label { display:block; background:#fff; border:1.5px solid #cfd9d2; border-radius:8px; padding:9px 12px; margin:7px 0; cursor:pointer; font-size:14.5px; }
.mcq label.correct { border-color:#1a7a2e; background:#eaf6ec; }
.mcq label.wrong { border-color:#b02a2a; background:#fdf1f1; }
.mcq .exp { display:none; font-size:13.5px; color:#333; background:#eef4f0; border-radius:7px; padding:8px 11px; margin-top:6px; }
.mcq .exp.open { display:block; }
.recap { background:var(--green); color:#fff; border-radius:12px; padding:14px 18px; margin:18px 0; font-size:14.5px; }
.recap b { color:var(--gold); }
.lesson-list a { display:block; background:#fff; border:1px solid #cfd9d2; border-radius:10px; padding:12px 15px; margin:9px 0; text-decoration:none; color:#1a1a1a; }
.lesson-list a:hover { border-color:var(--green); }
.lesson-list .locked { opacity:.5; pointer-events:none; }
.lesson-list .st { float:right; font-size:12.5px; font-weight:700; }
.st.done { color:#1a7a2e; } .st.todo { color:var(--gold); } .st.lock { color:#999; }
.progressbar { background:#e2e9e4; border-radius:9px; height:14px; overflow:hidden; margin:8px 0 4px; }
.progressbar div { background:linear-gradient(90deg,var(--green),var(--gold)); height:100%; width:0; transition:width .5s; }
.next { text-align:center; margin:26px 0 8px; }
footer { text-align:center; color:#888; font-size:12px; padding:20px; }
.small { font-size:12.5px; color:#666; }
.status-msg { font-size:13.5px; margin-top:8px; color:var(--green2); font-weight:600; }