/* ===== Study Quest — playful game UI (hoc tu IELTS Quest) ===== */
*{box-sizing:border-box;margin:0;padding:0}
:root{
  --bg1:#8ec5fc; --bg2:#e0c3fc;
  --card:#fff; --ink:#2d3142; --ink-soft:#6b7280;
  --primary:#58cc02; --primary-dark:#46a302;
  --blue:#1cb0f6; --blue-dark:#1899d6;
  --purple:#8549ba; --pink:#ff5fa2;
  --gold:#ffc800; --orange:#ff9600; --red:#ff4b4b;
  --radius:22px; --shadow:0 8px 24px rgba(45,49,66,.12);
}
html{font-size:16px}
body{font-family:'Baloo 2','Segoe UI',system-ui,sans-serif;color:var(--ink);
  background:linear-gradient(135deg,var(--bg1),var(--bg2)) fixed;min-height:100vh}
#app{max-width:880px;margin:0 auto;padding:16px 16px 96px}
button{font-family:inherit;cursor:pointer;border:none}
input,textarea,select{font-family:inherit;font-size:1rem}

/* loading */
.loading-screen{text-align:center;padding-top:30vh;font-size:1.2rem;color:#fff}
.mascot-bounce{font-size:5rem;animation:bounce 1s infinite alternate ease-in-out}
@keyframes bounce{from{transform:translateY(0)}to{transform:translateY(-22px)}}

/* chunky 3D buttons */
.btn{display:inline-block;padding:13px 26px;border-radius:16px;font-weight:800;font-size:1.05rem;color:#fff;
  text-align:center;background:var(--primary);box-shadow:0 5px 0 var(--primary-dark);
  transition:transform .08s,box-shadow .08s;user-select:none}
.btn:active{transform:translateY(4px);box-shadow:0 1px 0 var(--primary-dark)}
.btn:disabled{opacity:.45;cursor:not-allowed}
.btn.blue{background:var(--blue);box-shadow:0 5px 0 var(--blue-dark)}
.btn.blue:active{box-shadow:0 1px 0 var(--blue-dark)}
.btn.gold{background:var(--gold);color:#7a5b00;box-shadow:0 5px 0 #d9a800}
.btn.gold:active{box-shadow:0 1px 0 #d9a800}
.btn.ghost{background:#fff;color:var(--ink);box-shadow:0 5px 0 #d8d8e0;border:2px solid #e5e7eb}
.btn.ghost:active{box-shadow:0 1px 0 #d8d8e0}
.btn.small{padding:8px 16px;font-size:.92rem;border-radius:12px}
.btn.full{display:block;width:100%}

/* cards */
.card{background:var(--card);border-radius:var(--radius);box-shadow:var(--shadow);padding:20px;margin-bottom:16px}
.card h2{font-size:1.25rem;margin-bottom:12px;display:flex;align-items:center;gap:8px}
.card h3{font-size:1.05rem;margin:14px 0 8px}
.section-title{color:#fff;font-weight:800;font-size:1.3rem;text-shadow:0 2px 0 rgba(0,0,0,.12);margin:4px 0 12px}
.muted{color:var(--ink-soft);font-size:.9rem}
.center{text-align:center}
.mt{margin-top:14px}
.back{display:inline-block;font-weight:800;color:#fff;background:rgba(255,255,255,.25);
  border-radius:12px;padding:7px 14px;margin-bottom:12px;cursor:pointer}

/* login */
.login-wrap{max-width:420px;margin:6vh auto 0;text-align:center}
.login-logo{font-size:4.2rem;animation:bounce 1.4s infinite alternate ease-in-out}
.login-title{font-size:2.2rem;font-weight:800;color:#fff;text-shadow:0 3px 0 rgba(0,0,0,.15);margin:4px 0 2px}
.login-sub{color:#fff;opacity:.92;margin-bottom:20px;font-weight:600}
.login-card{text-align:left}
.field{margin-bottom:14px}
.field label{font-weight:700;display:block;margin-bottom:5px}
.field input{width:100%;padding:12px 14px;border-radius:14px;border:2px solid #e5e7eb;outline:none;background:#fafafa;transition:border-color .15s}
.field input:focus{border-color:var(--blue);background:#fff}
.login-hint{font-size:.85rem;color:var(--ink-soft);margin-top:12px;text-align:center}
.err{color:var(--red);font-weight:700;min-height:18px;margin-top:6px;text-align:center}

/* top bar (profile) */
.topbar{display:flex;align-items:center;gap:10px;flex-wrap:wrap;background:var(--card);
  border-radius:var(--radius);box-shadow:var(--shadow);padding:12px 18px;margin-bottom:16px}
.topbar .avatar{font-size:2.2rem}
.topbar .who{flex:1;min-width:130px}
.topbar .who .name{font-weight:800;font-size:1.05rem;line-height:1.1}
.topbar .who .lvl{font-size:.82rem;color:var(--ink-soft);font-weight:600}
.stat-chip{display:flex;align-items:center;gap:5px;font-weight:800;background:#f3f4f6;padding:7px 13px;border-radius:999px;font-size:.95rem}
.stat-chip.fire{color:var(--orange)} .stat-chip.coin{color:#b8860b} .stat-chip.xp{color:var(--purple)}
.xpbar-wrap{width:100%;margin-top:8px}
.xpbar{height:14px;background:#e5e7eb;border-radius:999px;overflow:hidden}
.xpbar>div{height:100%;background:linear-gradient(90deg,var(--purple),var(--pink));border-radius:999px;transition:width .6s ease}
.xpbar-label{font-size:.78rem;color:var(--ink-soft);font-weight:600;margin-top:3px;text-align:right}

/* bottom nav */
.navbar{position:fixed;bottom:0;left:0;right:0;z-index:50;background:#fff;box-shadow:0 -4px 18px rgba(0,0,0,.1);
  display:flex;justify-content:center;gap:4px;padding:6px 8px calc(6px + env(safe-area-inset-bottom))}
.navbar button{background:none;flex:1;max-width:150px;padding:7px 4px;border-radius:14px;font-weight:700;font-size:.78rem;
  color:var(--ink-soft);display:flex;flex-direction:column;align-items:center;gap:1px}
.navbar button .ico{font-size:1.5rem}
.navbar button.active{background:#eef7ff;color:var(--blue)}

/* CTA big */
.cta{display:block;width:100%;margin-bottom:16px;background:var(--primary);color:#fff;font-size:1.3rem;font-weight:800;
  padding:18px;border-radius:var(--radius);box-shadow:0 6px 0 var(--primary-dark);transition:transform .08s,box-shadow .08s}
.cta:active{transform:translateY(5px);box-shadow:0 1px 0 var(--primary-dark)}

/* quests */
.quest{display:flex;align-items:center;gap:12px;padding:10px 0;border-bottom:1px dashed #e5e7eb}
.quest:last-of-type{border-bottom:none}
.quest .qicon{font-size:1.7rem}
.quest .qbody{flex:1}
.quest .qlabel{font-weight:700;font-size:.95rem}
.quest .qbar{height:10px;background:#e5e7eb;border-radius:999px;margin-top:4px;overflow:hidden}
.quest .qbar>div{height:100%;background:var(--gold);border-radius:999px;transition:width .5s}
.quest .qbar>div.full{background:var(--primary)}
.quest .qdone{color:var(--primary);font-size:1.4rem}
.quest-bonus{text-align:center;font-weight:800;color:var(--primary);padding-top:12px}

/* skill/course/unit tiles */
.skill-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(120px,1fr));gap:12px}
.skill-tile{background:var(--card);border-radius:var(--radius);box-shadow:var(--shadow);padding:16px 10px;text-align:center;
  cursor:pointer;transition:transform .12s;border:3px solid transparent}
.skill-tile:hover{transform:translateY(-4px) scale(1.02)}
.skill-tile.done{border-color:var(--primary)}
.skill-tile .ico{font-size:2.2rem;width:54px;height:54px;line-height:54px;margin:0 auto;border-radius:50%;
  background:linear-gradient(135deg,var(--blue),var(--purple));color:#fff;font-weight:800;font-size:1.4rem}
.skill-tile.done .ico{background:linear-gradient(135deg,#4ade80,var(--primary))}
.skill-tile .nm{font-weight:800;margin-top:8px;font-size:.85rem}
.skill-tile .sub{font-size:.72rem;color:var(--ink-soft);font-weight:600}

.unit-row{display:flex;align-items:center;gap:14px;background:var(--card);border-radius:var(--radius);box-shadow:var(--shadow);
  padding:16px 18px;margin-bottom:12px;cursor:pointer;transition:transform .12s}
.unit-row:hover{transform:translateX(4px)}
.unit-row .uico{font-size:2.4rem}
.unit-row .ubody{flex:1}
.unit-row .utitle{font-weight:800}
.unit-row .usub{font-size:.82rem;color:var(--ink-soft);font-weight:600;margin-top:4px}
.unit-row .ubar{height:9px;background:#e5e7eb;border-radius:999px;margin-top:6px;overflow:hidden}
.unit-row .ubar>div{height:100%;border-radius:999px}
.badge-done{background:#e8f9e0;color:var(--primary-dark);font-size:.75rem;font-weight:800;padding:3px 10px;border-radius:999px}

/* theory tile + page */
.theory-tile{display:flex;align-items:center;gap:8px;background:#f5f3ff;border:2px solid #ddd6fe;border-radius:16px;
  padding:12px 14px;margin:6px 0 12px;cursor:pointer;font-weight:700;transition:transform .1s}
.theory-tile:hover{transform:translateY(-2px)}
.theory-tile .tgo{margin-left:auto;color:var(--purple);font-size:1.4rem}
.lesson-box{background:#f5f3ff;border:2px solid #ddd6fe;border-radius:16px;padding:8px 16px;margin-bottom:14px}
.theory-p{font-size:1rem;line-height:1.7;margin:10px 0}
.example{background:#eef2ff;border:2px solid #c7d2fe;border-radius:14px;padding:12px 15px;margin:10px 0}
.ex-de{margin-bottom:6px} .ex-giai{color:var(--primary-dark)}

/* quiz player */
.q-card{background:var(--card);border-radius:var(--radius);box-shadow:var(--shadow);padding:24px 22px}
.q-num{font-size:.85rem;font-weight:800;color:var(--blue);text-transform:uppercase}
.q-text{font-size:1.25rem;font-weight:700;margin:8px 0 18px;line-height:1.5}
.opt{display:flex;align-items:center;gap:10px;width:100%;text-align:left;background:#fafafa;border:2px solid #e5e7eb;
  border-radius:16px;padding:13px 16px;font-size:1.05rem;font-weight:700;margin-bottom:10px;transition:all .12s;cursor:pointer}
.opt:hover{border-color:var(--blue);background:#f0f9ff}
.opt.sel{border-color:var(--blue);background:#e0f2fe;box-shadow:0 3px 0 var(--blue-dark)}
.opt input{display:none}
.gap-input{width:100%;padding:14px 16px;border-radius:16px;border:2px solid #e5e7eb;font-size:1.1rem;font-weight:700;outline:none}
.gap-input:focus{border-color:var(--blue)}
.q-actions{display:flex;gap:10px;margin-top:18px;flex-wrap:wrap}
.pal{display:flex;flex-wrap:wrap;gap:6px;margin-top:10px}
.key{background:#f2f5f9;color:var(--blue);border:2px solid #e5e7eb;border-radius:12px;padding:7px 13px;font-size:1.05rem;font-weight:800}
.key:hover{background:#e3ebf4}
.tf{display:flex;gap:10px;margin-top:6px}
.tf-btn{flex:1;background:#fafafa;border:2px solid #e5e7eb;color:var(--ink);border-radius:16px;padding:14px;font-size:1.1rem;font-weight:800}
.tf-btn.sel{border-color:var(--blue);background:#e0f2fe}
.steps{display:flex;flex-direction:column;gap:8px;margin-top:6px}
.step-item{display:flex;justify-content:space-between;align-items:center;border:2px solid #e5e7eb;border-radius:14px;padding:11px 14px;background:#fafafa}
.step-text{flex:1} .step-btns{display:flex;gap:4px}
.mini{background:#eef1f5;color:var(--blue);border-radius:10px;padding:5px 11px;font-size:1rem;font-weight:800}
.mini:disabled{opacity:.4}
.hint{background:#fffbeb;border:2px solid #fde68a;border-radius:14px;padding:10px 14px;margin:8px 0;font-size:.98rem}
.sol{background:#f0fdf4;border:2px solid #bbf7d0;border-radius:14px;padding:10px 14px;margin:8px 0;font-size:.98rem}
.feedback{margin-top:14px;font-weight:800;font-size:1.05rem}
.feedback.good{color:var(--primary-dark)} .feedback.bad{color:var(--red)}

/* parent report */
.stats{display:flex;gap:12px;flex-wrap:wrap;margin:6px 0}
.stat{background:#f3f4f6;border-radius:16px;padding:12px 18px;text-align:center;min-width:90px}
.stat b{display:block;font-size:1.5rem;color:var(--purple)}
.stat span{font-size:.78rem;color:var(--ink-soft);font-weight:700}
.mastery-bar{height:12px;border-radius:999px;background:#e5e7eb;overflow:hidden;margin-top:4px}
.mastery-fill{height:100%;border-radius:999px}
.fill-xanh{background:var(--primary)} .fill-vang{background:var(--gold)} .fill-do{background:var(--red)}

/* toast / confetti / overlay */
#toast-area{position:fixed;top:14px;left:50%;transform:translateX(-50%);z-index:200;display:flex;flex-direction:column;gap:8px;align-items:center}
.toast{background:var(--ink);color:#fff;padding:12px 22px;border-radius:999px;font-weight:700;box-shadow:0 8px 24px rgba(0,0,0,.25);
  animation:toastIn .3s ease;max-width:90vw;text-align:center}
.toast.success{background:var(--primary)} .toast.error{background:var(--red)}
.toast.badge{background:linear-gradient(135deg,var(--gold),var(--orange));color:#5b4300;font-size:1.05rem}
@keyframes toastIn{from{opacity:0;transform:translateY(-16px)}to{opacity:1;transform:translateY(0)}}
#confetti{position:fixed;inset:0;pointer-events:none;z-index:150}
.overlay{position:fixed;inset:0;background:rgba(0,0,0,.55);z-index:180;display:flex;align-items:center;justify-content:center;padding:20px}
.overlay .panel{background:#fff;border-radius:26px;padding:34px 28px;text-align:center;max-width:380px;animation:popIn .35s cubic-bezier(.18,.89,.32,1.28)}
@keyframes popIn{from{transform:scale(.6);opacity:0}to{transform:scale(1);opacity:1}}
.overlay .panel .pico{font-size:4.5rem}
.overlay .panel h2{margin:8px 0;justify-content:center}

@media (max-width:560px){ html{font-size:15px} .q-text{font-size:1.1rem} .topbar{padding:10px 14px} }

/* ===== hinh ve & hoi dap ===== */
.figure{background:#fff;border:2px solid #e5e7eb;border-radius:16px;padding:12px;margin:12px 0;text-align:center}
.figure svg{max-width:100%;height:auto}
.fig-cap{font-size:.82rem;color:var(--ink-soft);font-weight:600;margin-top:6px}
.qa{border:2px solid #e5e7eb;border-radius:14px;margin:8px 0;overflow:hidden;background:#fafafa}
.qa-q{padding:11px 14px;font-weight:700;cursor:pointer;display:flex;align-items:center;gap:8px}
.qa-q .qa-tg{margin-left:auto;color:var(--blue);transition:transform .2s}
.qa.open .qa-q .qa-tg{transform:rotate(180deg)}
.qa-a{display:none;padding:0 14px 12px;color:var(--ink-soft);line-height:1.6}
.qa.open .qa-a{display:block}