:root{
  --teal:#0e7c86; --teal-dark:#0a5f66; --teal-light:#e0f2f4;
  --bg:#f4f7fb; --card:#ffffff; --ink:#1c2733; --muted:#5b6b7c;
  --gold:#f5c542; --green:#22a06b; --red:#e05252;
  --radius:16px;
}
*{box-sizing:border-box; -webkit-tap-highlight-color:transparent;}
html,body{margin:0;padding:0;}
body{
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Arial,sans-serif;
  background:var(--bg); color:var(--ink);
  min-height:100vh; padding-bottom:86px;
}
#app{max-width:640px;margin:0 auto;padding:14px 14px 20px;}

/* ---------- boot / login ---------- */
.boot{text-align:center;padding:70px 20px;color:var(--muted);}
.boot-logo{font-size:3.2rem;}
.boot-title{font-size:1.5rem;font-weight:800;color:var(--ink);margin-top:8px;}
.boot-sub{margin-top:6px;font-size:.9rem;}
.login-card{background:var(--card);border-radius:20px;padding:26px 22px;margin-top:26px;
  box-shadow:0 10px 30px rgba(14,124,134,.12);}
.login-card h1{margin:0 0 4px;font-size:1.35rem;}
.login-card p{color:var(--muted);font-size:.92rem;line-height:1.55;}
.btn{display:block;width:100%;border:none;border-radius:999px;padding:14px;font:inherit;
  font-weight:700;font-size:1rem;cursor:pointer;margin-top:10px;}
.btn-primary{background:var(--teal);color:#fff;}
.btn-primary:active{background:var(--teal-dark);}
.btn-ghost{background:var(--teal-light);color:var(--teal-dark);}
.btn-warn{background:#fff7e6;color:#7a5b00;border:2px solid var(--gold);}
.input{width:100%;font:inherit;padding:13px 14px;border:2px solid #dbe7ee;border-radius:12px;margin-top:8px;}
.input:focus{outline:none;border-color:var(--teal);}
.hr{display:flex;align-items:center;gap:10px;color:var(--muted);font-size:.8rem;margin:16px 0 6px;}
.hr::before,.hr::after{content:"";flex:1;height:1px;background:#dbe7ee;}
.err{background:#fdecec;color:#a02c2c;border-radius:10px;padding:10px 12px;font-size:.85rem;margin-top:10px;display:none;}
.linklike{background:none;border:none;color:var(--teal);font:inherit;font-size:.88rem;cursor:pointer;padding:6px 0;}

/* ---------- header / cards ---------- */
.topbar{display:flex;align-items:center;justify-content:space-between;margin:4px 2px 12px;}
.topbar h2{margin:0;font-size:1.2rem;}
.streak{background:#fff;border-radius:999px;padding:7px 14px;font-weight:800;font-size:.9rem;
  box-shadow:0 2px 8px rgba(0,0,0,.06);}
.xpbar{background:var(--card);border-radius:var(--radius);padding:12px 14px;margin-bottom:12px;
  box-shadow:0 2px 10px rgba(0,0,0,.05);}
.xpbar .row{display:flex;justify-content:space-between;font-size:.82rem;color:var(--muted);margin-bottom:6px;}
.xpbar .row b{color:var(--ink);}
.track{height:8px;background:#e8eef3;border-radius:99px;overflow:hidden;}
.track > div{height:100%;background:linear-gradient(90deg,var(--teal),#19b3c0);border-radius:99px;transition:width .3s;}
.grid{display:grid;grid-template-columns:1fr 1fr;gap:10px;}
.disc{background:var(--card);border-radius:var(--radius);padding:16px 14px;box-shadow:0 2px 10px rgba(0,0,0,.05);
  cursor:pointer;border:2px solid transparent;text-align:left;font:inherit;}
.disc:active{border-color:var(--teal);}
.disc .emoji{font-size:1.7rem;}
.disc h3{margin:8px 0 2px;font-size:.98rem;}
.disc small{color:var(--muted);font-size:.78rem;}
.disc .pbar{margin-top:10px;}
.chapter{margin:14px 2px 6px;font-size:.82rem;font-weight:800;color:var(--muted);text-transform:uppercase;letter-spacing:.5px;}
.topic{background:var(--card);border-radius:12px;padding:13px 14px;margin-bottom:8px;display:flex;
  align-items:center;justify-content:space-between;gap:10px;cursor:pointer;box-shadow:0 1px 6px rgba(0,0,0,.04);
  border:none;width:100%;font:inherit;text-align:left;}
.topic .t{font-weight:600;font-size:.93rem;}
.topic .c{font-size:.75rem;color:var(--muted);margin-top:2px;}
.topic .pct{font-size:.78rem;font-weight:800;color:var(--teal);white-space:nowrap;}
.back{background:none;border:none;color:var(--teal);font:inherit;font-weight:700;cursor:pointer;padding:8px 0;font-size:.95rem;}

/* ---------- flip cards ---------- */
.progress-line{font-size:.82rem;color:var(--muted);margin:2px 2px 10px;display:flex;justify-content:space-between;}
.fcard{background:var(--card);border-radius:20px;min-height:300px;display:flex;flex-direction:column;
  justify-content:center;align-items:center;text-align:center;padding:28px 22px;cursor:pointer;
  box-shadow:0 8px 24px rgba(14,124,134,.12);user-select:none;}
.fcard .q{font-size:1.12rem;font-weight:700;line-height:1.5;}
.fcard .a{font-size:1.02rem;line-height:1.6;white-space:pre-line;}
.fcard .hint{margin-top:14px;font-size:.75rem;color:var(--muted);}
.fcard.flipped{background:#f0fafb;border:2px solid var(--teal-light);}
.fcard-nav{display:flex;gap:10px;margin-top:14px;}
.fcard-nav .btn{margin-top:0;}
.star-row{display:flex;justify-content:center;gap:10px;margin-top:10px;}
.iconbtn{background:var(--card);border:2px solid #dbe7ee;border-radius:999px;width:52px;height:52px;
  font-size:1.3rem;cursor:pointer;}
.iconbtn.on{border-color:var(--gold);background:#fff7e6;}
.demo-note{background:#fff7e6;border:2px solid var(--gold);border-radius:12px;padding:12px 14px;
  font-size:.85rem;color:#7a5b00;margin-bottom:12px;line-height:1.5;}

/* ---------- lock / paywall ---------- */
.lock{background:var(--card);border-radius:20px;padding:30px 22px;text-align:center;
  box-shadow:0 10px 30px rgba(14,124,134,.12);margin-top:20px;}
.lock .big{font-size:3rem;}
.lock h2{margin:10px 0 6px;}
.lock p{color:var(--muted);font-size:.92rem;line-height:1.6;}
.code-row{display:flex;gap:8px;margin-top:12px;}
.code-row .input{margin-top:0;font-family:monospace;text-transform:uppercase;}

/* ---------- MCQ ---------- */
.mcq-setup{background:var(--card);border-radius:var(--radius);padding:18px;box-shadow:0 2px 10px rgba(0,0,0,.05);}
.opt{display:block;width:100%;text-align:left;background:var(--card);border:2px solid #dbe7ee;
  border-radius:12px;padding:14px;font:inherit;font-size:.95rem;margin-bottom:10px;cursor:pointer;line-height:1.45;}
.opt.correct{border-color:var(--green);background:#e9f9f1;}
.opt.wrong{border-color:var(--red);background:#fdecec;}
.opt:disabled{cursor:default;opacity:.95;}
.opt .letter{display:inline-block;width:26px;height:26px;border-radius:50%;background:var(--teal-light);
  color:var(--teal-dark);font-weight:800;font-size:.8rem;text-align:center;line-height:26px;margin-right:10px;}
.mcq-q{background:var(--card);border-radius:var(--radius);padding:20px 18px;margin-bottom:14px;
  font-size:1.05rem;font-weight:700;line-height:1.55;box-shadow:0 2px 10px rgba(0,0,0,.05);}
.mcq-explain{background:#eef6ff;border-radius:12px;padding:12px 14px;font-size:.88rem;margin:12px 0;line-height:1.55;}
.result{background:var(--card);border-radius:20px;padding:28px 22px;text-align:center;
  box-shadow:0 10px 30px rgba(14,124,134,.12);margin-top:16px;}
.result .score{font-size:2.6rem;font-weight:800;color:var(--teal);}
.quizpick{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:12px;}

/* ---------- leaderboard ---------- */
.tabs{display:flex;gap:8px;margin-bottom:12px;}
.tabs button{flex:1;border:none;border-radius:999px;padding:10px;font:inherit;font-weight:700;
  background:var(--teal-light);color:var(--teal-dark);cursor:pointer;font-size:.88rem;}
.tabs button.on{background:var(--teal);color:#fff;}
.lb-row{display:flex;align-items:center;gap:12px;background:var(--card);border-radius:12px;
  padding:11px 14px;margin-bottom:8px;box-shadow:0 1px 6px rgba(0,0,0,.04);}
.lb-row.me{border:2px solid var(--teal);}
.lb-rank{font-weight:800;width:30px;text-align:center;font-size:1rem;}
.lb-name{flex:1;font-weight:600;font-size:.92rem;}
.lb-xp{font-weight:800;color:var(--teal);font-size:.9rem;white-space:nowrap;}
.avatar{width:34px;height:34px;border-radius:50%;background:var(--teal-light);display:flex;
  align-items:center;justify-content:center;font-weight:800;color:var(--teal-dark);overflow:hidden;flex:none;}
.avatar img{width:100%;height:100%;object-fit:cover;}

/* ---------- plan ---------- */
.week{background:var(--card);border-radius:var(--radius);padding:16px;margin-bottom:10px;
  box-shadow:0 2px 10px rgba(0,0,0,.05);}
.week-head{display:flex;justify-content:space-between;align-items:center;cursor:pointer;
  background:none;border:none;width:100%;font:inherit;text-align:left;padding:0;}
.week-head h3{margin:0;font-size:.98rem;}
.week-head small{color:var(--muted);}
.phase{display:inline-block;font-size:.7rem;font-weight:800;background:var(--teal-light);
  color:var(--teal-dark);border-radius:99px;padding:3px 10px;margin-bottom:8px;}
.task{display:flex;gap:10px;align-items:flex-start;padding:9px 0;border-top:1px solid #eef2f6;
  font-size:.9rem;line-height:1.5;cursor:pointer;}
.task input{width:20px;height:20px;margin-top:2px;accent-color:var(--teal);flex:none;}
.task.done span{text-decoration:line-through;color:var(--muted);}

/* ---------- profile ---------- */
.kv{background:var(--card);border-radius:var(--radius);padding:16px;margin-bottom:10px;
  box-shadow:0 2px 10px rgba(0,0,0,.05);font-size:.92rem;}
.kv .r{display:flex;justify-content:space-between;padding:7px 0;border-bottom:1px solid #eef2f6;}
.kv .r:last-child{border-bottom:none;}
.kv .k{color:var(--muted);}
.kv .v{font-weight:700;}
.badge{display:inline-block;background:linear-gradient(135deg,#f5c542,#e8a91c);color:#5c430a;
  font-weight:800;font-size:.75rem;border-radius:99px;padding:4px 12px;}

/* ---------- tabbar / toast ---------- */
.tabbar{position:fixed;bottom:0;left:0;right:0;background:#fff;border-top:1px solid #e3eaF0;
  display:flex;z-index:50;padding:6px 4px calc(8px + env(safe-area-inset-bottom));}
.tabbar button{flex:1;background:none;border:none;font-size:1.35rem;cursor:pointer;color:#9fb0bd;
  display:flex;flex-direction:column;align-items:center;gap:2px;font:inherit;}
.tabbar button span{font-size:.62rem;font-weight:700;}
.tabbar button.on{color:var(--teal);}
.toast{position:fixed;bottom:96px;left:50%;transform:translateX(-50%);background:#1c2733;color:#fff;
  padding:12px 20px;border-radius:999px;font-size:.88rem;z-index:99;box-shadow:0 6px 20px rgba(0,0,0,.25);
  max-width:90vw;text-align:center;}
.empty{text-align:center;color:var(--muted);padding:40px 20px;font-size:.92rem;line-height:1.6;}
.small{font-size:.8rem;color:var(--muted);line-height:1.55;}
.mt{margin-top:14px;}