:root{color:#1f2933;background:#f7f7f2;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;font-synthesis:none;text-rendering:optimizeLegibility;-webkit-font-smoothing:antialiased}*{box-sizing:border-box}body{margin:0;min-width:320px;min-height:100vh;background:#f7f7f2}button{font:inherit}.app-shell{width:min(100%,900px);min-height:100vh;margin:0 auto;padding:12px clamp(12px,4vw,28px) 28px}.topbar{display:grid;grid-template-columns:48px 1fr 48px;align-items:center;gap:8px;min-height:58px}.topbar h1{margin:0;font-size:clamp(20px,5vw,30px);font-weight:720;text-align:center}.icon-button,.text-button,.primary-button,.secondary-button,.table-tile,.pad-button,.stats-row{min-width:44px;min-height:44px;border:1px solid #cfd7d2;background:#fff;color:#1f2933;border-radius:8px;cursor:pointer}.icon-button{display:inline-flex;align-items:center;justify-content:center}.text-button{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:10px 12px}.home-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:12px;margin-top:18px}.table-tile{display:flex;min-height:118px;flex-direction:column;align-items:flex-start;justify-content:center;gap:10px;padding:18px;text-align:left}.table-name{font-size:34px;font-weight:760}.practice-head{display:flex;justify-content:space-between;gap:10px;margin:14px 0}.task-surface{display:flex;min-height:180px;flex-direction:column;justify-content:center;gap:8px;padding:24px;border-top:1px solid #d9ded9;border-bottom:1px solid #d9ded9;background:#fffffb}.expression{line-height:1.15;font-weight:760}.answer-line{font-size:clamp(30px,9vw,46px);font-weight:720}.answer-panel,.hint-panel,.finish-panel{margin-top:18px}.answer-box{display:flex;min-height:64px;align-items:center;justify-content:center;margin-bottom:12px;border:1px solid #cfd7d2;border-radius:8px;background:#fff;font-size:36px;font-weight:720}.number-pad{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px}.pad-button{min-height:58px;font-size:26px;font-weight:700}.submit-pad{background:#214e5f;color:#fff}.primary-button,.secondary-button{display:inline-flex;align-items:center;justify-content:center;padding:13px 18px;font-weight:720}.primary-button{border-color:#214e5f;background:#214e5f;color:#fff}.secondary-button{background:#fff}.wide{width:100%;margin-top:12px}.strategy{display:grid;gap:8px;margin:12px 0}.strategy h3{margin:0 0 4px;font-size:18px}.strategy-step{padding:11px 12px;border:1px solid #d9ded9;border-radius:8px;background:#fff;font-size:20px;font-weight:650}.overlay{position:fixed;inset:0;display:flex;align-items:end;justify-content:center;padding:16px;background:#1f29332e}.feedback-panel{width:min(100%,520px);padding:20px;border-radius:8px;background:#fffffb;box-shadow:0 12px 32px #1f293329}.feedback-panel h2,.finish-panel h2{margin:0 0 8px}.feedback-panel p{margin:0;font-size:28px;font-weight:720}.actions-row{display:flex;flex-wrap:wrap;gap:10px}.summary-strip{display:flex;flex-wrap:wrap;gap:8px;margin:12px 0 16px}.summary-strip span{padding:8px 10px;border:1px solid #d9ded9;border-radius:8px;background:#fff}.stats-list,.fact-table{display:grid;gap:10px;margin-top:16px}.stats-row{display:grid;gap:6px;padding:14px;text-align:left}.stats-row span:first-child{font-size:22px;font-weight:720}.fact-table{grid-template-columns:repeat(auto-fit,minmax(230px,1fr))}.fact-card{padding:14px;border:1px solid #d9ded9;border-radius:8px;background:#fff}.fact-card h2{margin:0 0 10px}.fact-card dl{display:grid;gap:6px;margin:0}.fact-card dl div{display:flex;justify-content:space-between;gap:12px}.fact-card dt{color:#52606d}.fact-card dd{margin:0;font-weight:700}@media(max-width:520px){.app-shell{padding-inline:10px}.home-grid{grid-template-columns:1fr}.table-tile{min-height:96px}.practice-head{align-items:stretch;flex-direction:column}.task-surface{min-height:160px;padding:18px}.number-pad{gap:8px}.pad-button{min-height:62px}.overlay{align-items:stretch;padding:10px}.feedback-panel{align-self:end}}