/* Math Battle styles (all art is CSS / pixel SVG). Phone portrait first; big tap targets (>= 52px). */
.bt-shell{max-width:820px;padding-bottom:84px}   /* room for the floating music button */
.bt-card{background:#fff;border:1px solid var(--line);border-radius:22px;padding:22px;box-shadow:var(--shadow)}
.bt-card.center{text-align:center}
.bt-pix{display:block;image-rendering:pixelated}
.bt-h2{font-size:1.1rem;margin:18px 0 8px}
/* menu */
.bt-menu{text-align:center}
.bt-menu h1{font-size:2.2rem;margin:6px 0}
.bt-hero-row{display:flex;align-items:flex-end;justify-content:center;gap:10px;margin-bottom:6px}
.bt-me svg{display:block}
.bt-me-buddy{margin-left:-8px}
.bt-vs{font-weight:900;font-size:1.4rem;color:var(--coral);align-self:center;padding:0 6px}
.bt-grades{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin:0 auto;max-width:560px}
.bt-grade{border:3px solid var(--line);background:#fff;border-radius:16px;padding:12px 6px;min-height:68px;font:inherit;color:var(--ink);cursor:pointer;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:2px;-webkit-tap-highlight-color:transparent}
.bt-grade b{font-size:1.15rem}.bt-grade small{font-size:.74rem;font-weight:700;color:var(--ink-soft);line-height:1.2}
.bt-grade[aria-pressed="true"]{border-color:var(--brand);background:var(--brand-soft);box-shadow:0 0 0 3px rgba(79,70,229,.18)}
.bt-how{list-style:none;padding:0;margin:18px auto;max-width:520px;text-align:left}
.bt-how li{padding:5px 0}
.bt-start{font-size:1.3rem;padding:16px 44px;min-height:60px}
/* fight */
.bt-fight{padding:14px}
.bt-top{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:10px}
.bt-chip{background:var(--brand-soft);color:var(--brand-dark);border-radius:999px;padding:4px 14px;font-weight:800;font-size:.9rem}
.bt-streak{background:#ffedd5;color:#9a3412}
.is-boss .bt-chip:first-child{background:#ffe4e6;color:#9f1239}
.bt-arena{position:relative;height:310px;border-radius:18px;overflow:hidden;background:linear-gradient(#7cc8ff 0,#cdeeff 56%,#8bd86f 56%,#5db74c 100%);border:3px solid #2b2140;isolation:isolate}
.is-boss .bt-arena{background:linear-gradient(#ffb4a0 0,#ffe3c2 56%,#9bd86f 56%,#63b650 100%)}
.bt-arena:after{content:"";position:absolute;left:0;right:0;top:56%;height:6px;background:rgba(0,0,0,.08)}
.bt-cloud{position:absolute;background:#fff;border-radius:999px;opacity:.9;height:16px;z-index:0}
.bt-cloud:before{content:"";position:absolute;left:14px;top:-10px;width:30px;height:20px;background:#fff;border-radius:999px}
.bt-cloud.c1{width:70px;top:46%;left:38%;animation:btDrift 26s linear infinite}.bt-cloud.c2{width:50px;top:36%;left:70%;animation:btDrift 34s linear infinite reverse}
@keyframes btDrift{0%{transform:translateX(-30px)}50%{transform:translateX(30px)}100%{transform:translateX(-30px)}}
.bt-plate{position:absolute;top:8px;width:46%;max-width:250px;background:rgba(255,255,255,.92);border:2px solid #2b2140;border-radius:12px;padding:5px 9px;z-index:5;font-weight:800;font-size:.88rem}
.bt-plate-me{left:8px}.bt-plate-mon{right:8px}
.bt-pname{white-space:nowrap;overflow:hidden;text-overflow:ellipsis;line-height:1.25}.bt-pname small{font-weight:700;color:var(--ink-soft);font-size:.72rem}
.bt-hp{position:relative;height:17px;background:#ddd;border-radius:999px;overflow:hidden;border:2px solid #2b2140;margin-top:3px}
.bt-hp>i{display:block;height:100%;background:linear-gradient(#6ee787,#22b14c);transition:width .45s ease}
.bt-hp.low>i{background:linear-gradient(#ffb199,#f43f5e)}
.bt-hp-mon>i{background:linear-gradient(#ffd27a,#ff8a3d)}
.bt-hp>span{position:absolute;inset:0;display:grid;place-items:center;font-size:.68rem;font-weight:900;color:#1b1535;text-shadow:0 0 3px #fff,0 0 3px #fff}
.bt-charge{display:flex;align-items:center;gap:4px;margin-top:4px;font-size:.7rem}
.bt-charge i{width:14px;height:14px;transform:rotate(45deg);background:#d9d2ee;border:2px solid #2b2140;display:block}
.bt-charge i.on{background:#ffd83a;box-shadow:0 0 8px #ffb300}
.bt-charge em{font-style:normal;margin-left:8px;color:var(--ink-soft);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.bt-hero,.bt-buddy,.bt-mon{position:absolute;bottom:13%;z-index:3;transition:transform .15s}
.bt-hero{left:12%}
.bt-buddy{left:2%;bottom:12%;z-index:4}
.bt-buddy .bd-svg,.bt-buddy svg{display:block;image-rendering:pixelated;animation:btBob 1.6s ease-in-out infinite}
.bt-mon{right:9%}
.bt-mon .bt-pix{animation:btBob 2.2s ease-in-out infinite}
@keyframes btBob{0%,100%{transform:translateY(0)}50%{transform:translateY(-5px)}}
.bt-in{animation:btIn .6s cubic-bezier(.2,1.5,.4,1) both}@keyframes btIn{0%{transform:translateX(70px) scale(.5);opacity:0}100%{transform:none;opacity:1}}
.bt-hero.lunge{animation:btLunge .6s ease}@keyframes btLunge{0%{transform:translateX(0)}35%{transform:translateX(min(34vw,230px))}100%{transform:translateX(0)}}
.bt-mon.lunge-l{animation:btLungeL .6s ease}@keyframes btLungeL{0%{transform:translateX(0)}35%{transform:translateX(max(-34vw,-230px))}100%{transform:translateX(0)}}
.bt-buddy.dash{animation:btDash .9s ease}@keyframes btDash{0%{transform:translate(0,0)}40%{transform:translate(min(48vw,340px),-40px) scale(1.4)}60%{transform:translate(min(48vw,340px),-20px) scale(1.4)}100%{transform:translate(0,0)}}
.bt-mon.hurt,.bt-hero.hurt{animation:btHurt .55s ease}@keyframes btHurt{0%,100%{transform:translateX(0);filter:none}15%{transform:translateX(-10px);filter:brightness(2.4)}35%{transform:translateX(9px)}55%{transform:translateX(-6px);filter:brightness(1.8)}75%{transform:translateX(3px)}}
.bt-mon.poof{animation:btPoof .9s ease forwards}@keyframes btPoof{0%{transform:scale(1);opacity:1}40%{transform:scale(1.15) rotate(4deg)}100%{transform:scale(.2) translateY(-60px);opacity:0}}
.bt-proj{position:absolute;left:24%;bottom:30%;z-index:6;font-size:2rem;filter:drop-shadow(0 0 6px #ffd83a);animation:btProj .5s ease-in forwards}
.bt-proj.sp{font-size:2.6rem;bottom:34%;filter:drop-shadow(0 0 10px #ff6adf)}
@keyframes btProj{0%{left:24%;transform:rotate(0) scale(.6)}100%{left:72%;transform:rotate(540deg) scale(1.2)}}
.bt-float{position:absolute;z-index:8;font-weight:900;font-size:1.6rem;color:#fff;text-shadow:-2px -2px 0 #2b2140,2px -2px 0 #2b2140,-2px 2px 0 #2b2140,2px 2px 0 #2b2140;transform:translateX(-50%);animation:btFloat 1.2s ease-out forwards;pointer-events:none}
.bt-float.dmg{color:#ff6b6b}.bt-float.big{font-size:2.3rem;color:#ffd83a}.bt-float.heal{color:#6ee787}
@keyframes btFloat{0%{opacity:0;margin-top:10px}15%{opacity:1}100%{opacity:0;margin-top:-56px}}
.bt-spark{position:absolute;width:10px;height:10px;background:#ffd83a;z-index:7;transform:rotate(45deg);animation:btSpark 1.1s ease-out forwards;box-shadow:0 0 6px #fff;pointer-events:none}
@keyframes btSpark{0%{opacity:1;transform:translate(0,0) rotate(45deg)}100%{opacity:0;transform:translate(var(--dx),var(--dy)) rotate(225deg) scale(.3)}}
.bt-say{position:absolute;left:50%;top:44%;transform:translate(-50%,-50%) scale(.6);z-index:9;background:#fff;border:3px solid #2b2140;border-radius:14px;padding:6px 14px;font-weight:900;font-size:1rem;opacity:0;transition:opacity .2s,transform .2s;max-width:86%;text-align:center;pointer-events:none}
.bt-say.on{opacity:1;transform:translate(-50%,-50%) scale(1)}
/* panel */
.bt-panel{padding:16px 4px 4px}
.bt-qtopic{font-size:.78rem;font-weight:800;letter-spacing:.06em;text-transform:uppercase;color:var(--teal)}
.bt-qprompt{font-size:1.3rem;font-weight:700;margin:4px 0 14px;line-height:1.4}
.bt-opts{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-bottom:12px}
.bt-opt{display:flex;align-items:center;gap:10px;text-align:left;border:3px solid var(--line);background:#fff;border-radius:16px;padding:10px 12px;min-height:60px;font:inherit;font-size:1.1rem;font-weight:800;color:var(--ink);cursor:pointer;width:100%;-webkit-tap-highlight-color:transparent}
.bt-opt .letter{width:32px;height:32px;border-radius:50%;background:var(--brand-soft);color:var(--brand-dark);display:grid;place-items:center;font-weight:900;flex:none}
.bt-opt:hover:not([disabled]){border-color:var(--brand);background:var(--brand-soft)}
.bt-opt:active:not([disabled]){transform:scale(.98)}
.bt-opt.right{border-color:var(--green);background:var(--green-soft)}.bt-opt.wrong{border-color:var(--red);background:var(--red-soft)}.bt-opt[disabled]{cursor:default}
.bt-answer{display:flex;gap:10px;margin-bottom:8px}
.bt-answer input{flex:1;min-width:0;font:inherit;font-size:1.4rem;font-weight:800;padding:12px 14px;border:3px solid var(--line);border-radius:14px;color:var(--ink);min-height:58px}
.bt-answer input:focus{border-color:var(--brand);outline:none}.bt-answer input.right{border-color:var(--green);background:var(--green-soft)}.bt-answer input.wrong{border-color:var(--red);background:var(--red-soft)}
.bt-answer .btn{min-height:58px;font-size:1.15rem;white-space:nowrap}
.bt-fb{border-radius:14px;padding:10px 14px;margin:8px 0}
.bt-fb.good{background:var(--green-soft);border:2px solid #86efac}.bt-fb.bad{background:var(--red-soft);border:2px solid #fca5a5}
.bt-fb strong{display:inline-block}
#bt-next,.bt-big{width:100%;min-height:56px;font-size:1.15rem;margin-top:4px}
.bt-win{text-align:center;padding:6px 0}.bt-win h2{margin:6px 0 8px}.bt-heal{margin:6px 0 12px;font-weight:700}
.bt-end-art{display:flex;align-items:flex-end;justify-content:center;gap:10px;margin-bottom:6px}
.bt-end h1{font-size:1.9rem;margin:6px 0}
@media (max-width:560px){
  .bt-card{padding:16px 12px}.bt-fight{padding:10px}
  .bt-arena{height:262px}
  .bt-plate{font-size:.8rem;padding:4px 7px;width:47%}.bt-charge em{display:none}
  .bt-hero svg{width:76px;height:auto}.bt-mon .bt-pix{width:96px;height:auto}.is-boss .bt-mon .bt-pix{width:128px}.bt-buddy svg{width:42px;height:auto}
  .bt-hero{left:11%}.bt-mon{right:6%}
  .bt-opts{grid-template-columns:1fr}.bt-qprompt{font-size:1.2rem}
  .bt-grades{grid-template-columns:repeat(2,1fr)}
  .bt-answer{flex-direction:column}
  .bt-menu h1{font-size:1.8rem}
}
@media (prefers-reduced-motion:reduce){.bt-mon .bt-pix,.bt-buddy svg,.bt-cloud,.bt-in,.bt-hero.lunge,.bt-mon.lunge-l,.bt-buddy.dash,.bt-proj,.bt-spark{animation:none!important}.bt-hp>i{transition:none}.bt-proj{display:none}}