:root{font-family:system-ui,-apple-system,"PingFang SC","Microsoft YaHei",sans-serif;color:#25204c;background:#f6f1ff}*{box-sizing:border-box}body{margin:0;min-height:100dvh;background:radial-gradient(circle at 15% 10%,#ffe1ec 0,transparent 34%),radial-gradient(circle at 90% 35%,#d8e5ff 0,transparent 35%),#f6f1ff}.app{width:min(100%,480px);min-height:100dvh;margin:auto;padding:max(22px,env(safe-area-inset-top)) 18px max(22px,env(safe-area-inset-bottom));display:flex;flex-direction:column;gap:18px}header,.brand,.cardtop,.controls{display:flex;align-items:center;justify-content:space-between}.brand{justify-content:flex-start;gap:12px}.spark{display:grid;place-items:center;width:48px;height:48px;border-radius:15px;background:#ffce47;color:#6e37db;font-size:35px;box-shadow:0 5px 0 #d9a838}h1{font-size:23px;margin:0}header p{margin:4px 0 0;font-size:12px;color:#716c8b}.round{border:0;border-radius:50%;width:44px;height:44px;background:#fff;color:#6449e8;font-size:24px;box-shadow:0 4px 12px #5a3ba71c}.dashboard{display:grid;grid-template-columns:repeat(3,1fr);gap:10px}.dashboard div{display:flex;flex-direction:column;align-items:center;background:#fff;border-radius:17px;padding:13px 4px;box-shadow:0 5px 15px #51348d12}.dashboard strong{font-size:25px;color:#6449e8}.dashboard span{font-size:12px;color:#716c8b}.card{background:#fff;border:3px solid #2e255d;border-radius:25px;padding:19px;box-shadow:0 8px 0 #2e255d}.cardtop{gap:8px;font-size:12px;color:#716c8b}.pill{border-radius:99px;background:#eee9ff;color:#6449e8;padding:7px 10px;font-weight:700}.equation{min-height:140px;display:flex;align-items:center;justify-content:center;gap:8px;font-size:clamp(30px,9vw,48px);font-weight:850;white-space:nowrap}.answer{display:grid;place-items:center;min-width:1.8em;height:1.3em;padding:0 .12em;border-bottom:5px solid #fb76aa;color:#6449e8}.feedback{height:42px;margin:0 0 12px;text-align:center;font-size:14px;font-weight:700;color:#665f7d}.feedback.correct{color:#13956b}.feedback.wrong{color:#db4474}.numberpad{display:grid;grid-template-columns:repeat(3,1fr);gap:9px}.numberpad button{height:53px;border:2px solid #2e255d;border-radius:14px;background:#fff8e4;color:#25204c;font-size:24px;font-weight:800;box-shadow:0 3px 0 #2e255d;touch-action:manipulation}.numberpad button:active,.submit:active,.controls button:active{transform:translateY(3px);box-shadow:none}.numberpad button[data-key="clear"],.numberpad button[data-key="back"]{font-size:17px;background:#fce6f0}.submit{width:100%;height:55px;margin-top:12px;border:2px solid #2e255d;border-radius:14px;background:#ffcf44;color:#282051;font-size:19px;font-weight:850;box-shadow:0 4px 0 #2e255d;touch-action:manipulation}.controls{gap:12px}.controls label{font-size:13px;font-weight:700}.controls select,.controls button{border:2px solid #ddd3fa;border-radius:10px;background:#fff;color:#3c336c;padding:9px;font:inherit;font-weight:700}.controls button{white-space:nowrap}footer{margin-top:auto;text-align:center;color:#928ba5;font-size:11px}@media(max-height:740px){.app{gap:10px}.card{padding:14px}.equation{min-height:104px}.numberpad button{height:46px}.feedback{height:36px;margin-bottom:6px}}@media(max-width:340px){.app{padding-inline:10px}.equation{gap:4px;font-size:30px}.card{padding:12px}}