.foundation-main{max-width:960px;margin:auto;padding:16px 18px 40px}.foundation-start{text-align:center;background:#f0f5e6;border:2px solid #d3e1c5;border-radius:28px;padding:26px;max-width:780px;margin:10px auto 30px}.foundation-start h1{font-size:clamp(1.65rem,4vw,2.5rem);line-height:1.2;margin:16px 0}.foundation-start p{line-height:1.6;max-width:600px;margin:12px auto}.foundation-hero{height:170px;display:flex;gap:15px;align-items:center;justify-content:center}.foundation-hero svg{height:160px;width:160px}.foundation-main button,.foundation-main .primary{font:inherit;color:inherit;cursor:pointer;border:2px solid #c8d9c7;border-radius:15px;background:#fffdf4;padding:10px 16px;min-height:44px;box-shadow:0 3px 0 #b8cbb52b;font-weight:650}.foundation-main .primary{display:inline-flex;align-items:center;justify-content:center;background:#578775;border:2px solid #497360;color:white;border-radius:16px;padding:12px 20px;text-decoration:none;font-weight:750;box-shadow:0 4px 0 #385f50}.foundation-main button:disabled{opacity:.5;cursor:default}.f-toolbar{display:flex;align-items:center;gap:8px}.f-toolbar strong{margin-right:auto;font-size:.95rem}.foundation-main .f-toolbar button{font-size:.8rem;padding:7px 10px;min-height:38px}.f-progress{display:flex;gap:14px;align-items:center;margin:12px 0;font-size:.85rem}.f-progress progress{appearance:none;border:0;border-radius:9px;overflow:hidden;background:#dce6d4;height:8px;flex:1}.f-progress progress::-webkit-progress-bar{background:#dce6d4}.f-progress progress::-webkit-progress-value{background:#84ad8c}.f-progress progress::-moz-progress-bar{background:#84ad8c}.f-question-row{display:flex;gap:12px;align-items:center;min-height:74px}.f-question-row h2{font-size:clamp(1.12rem,2.4vw,1.45rem);line-height:1.35;flex:1;margin:10px 0}.f-question-row button{min-width:44px}.foundation-scene{background:radial-gradient(ellipse at 20% 0,#fff6d8,transparent 75%),#e4efe0;border:2px solid #cbdeca;border-radius:27px;padding:25px 22px;min-height:270px;box-shadow:0 12px 24px #5574510c}.foundation-scene.shapes{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px;align-items:center}.foundation-main .shape-choice{padding:12px;background:#fffcf1;border-radius:24px;border:2px solid #bfd5c2;box-shadow:0 6px 0 #adc3ab;min-height:180px}.shape-choice svg{width:100%;height:170px;filter:drop-shadow(0 6px 1px #6c7f5a20)}.shape-choice:hover{transform:translateY(-3px)}.foundation-scene.length{display:flex;flex-direction:column;justify-content:center;gap:22px;padding:26px}.foundation-main .ribbon-choice{width:100%;display:flex;align-items:center;padding:18px 12px;min-height:78px;border:2px solid #ffffff90;border-radius:18px;background:#fffdf061;box-shadow:none}.ribbon{height:35px;display:block;min-width:30px;clip-path:polygon(0 0,100% 0,calc(100% - 14px) 50%,100% 100%,0 100%);border-left:5px solid #537f6d;background:linear-gradient(#a5d3c2,#79ac9b 45%,#9ac9b7);filter:drop-shadow(0 4px 0 #45654920)}.ribbon.rose{border-left-color:#a97a83;background:linear-gradient(#e8b5ba,#d397a1 45%,#e0a8b1)}.foundation-scene.measure{text-align:center}.ruler-board{max-width:760px;margin:auto}.measure-svg{display:block;width:100%;max-height:300px}.ruler-laid{animation:lay-ruler .4s ease-out}.f-answers{display:flex;justify-content:center;gap:14px;margin:17px 0 10px;flex-wrap:wrap}.foundation-main .number-choice{font-size:1.55rem;min-width:100px;min-height:66px;background:#fff8df;border-color:#d5bd8d;box-shadow:0 5px 0 #bfa67a}.f-feedback{min-height:48px;line-height:1.45;text-align:center;font-size:1rem;margin:8px 0;padding:8px;color:#637461}.f-feedback.good{color:#3f7956;font-weight:750}.f-actions{display:flex;gap:12px;justify-content:center}.f-hint{font-size:.84rem;line-height:1.45;color:#6d7d69;text-align:center;margin:12px auto;max-width:620px}.help-mark{outline:4px solid #e7b35e!important;outline-offset:4px;border-radius:18px}.group-boxes{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));max-width:650px;gap:18px;margin:auto}.group-box{position:relative;text-align:center}.foundation-main .group-bowl,.group-bowl{background:linear-gradient(145deg,#fffbea,#f3e1b6);border:3px solid #d9bf88;box-shadow:0 7px 0 #c7b17f;border-radius:24px;min-height:120px;display:flex;gap:5px;align-items:center;justify-content:center;flex-wrap:wrap;width:100%;padding:14px 10px}.group-bowl img{width:53px;height:53px;object-fit:contain;animation:group-pop .2s}.bowl-plus{font-size:36px;color:#a7b594}.foundation-main .group-undo{min-height:34px;font-size:23px;line-height:1;padding:3px 16px;margin-top:11px;border-radius:12px}.group-equation{text-align:center;font-size:1.35rem;font-weight:800;margin:25px 0 0;color:#547c65}.foundation-scene.tutorial.shapes{grid-template-columns:repeat(4,minmax(0,1fr));gap:12px}.tutorial-shape{text-align:center;background:#fffdf1;border-radius:22px;padding:12px}.tutorial-shape svg{width:100%;max-height:145px}.tutorial-shape span{display:block;font-weight:750}.foundation-result{text-align:center;background:#edf4e4;border:2px solid #d2e2c8;border-radius:25px;padding:30px}.foundation-result h2{font-size:1.7rem}.foundation-result details{text-align:left;margin-top:22px}.foundation-result .result-actions{display:flex;justify-content:center;gap:14px;flex-wrap:wrap}.foundation-thumb{height:240px;background:linear-gradient(135deg,#e1efe4,#fff1d5);display:flex;align-items:center;justify-content:center;gap:12px;padding:18px;overflow:hidden}.foundation-thumb svg{width:100%;max-height:200px}.foundation-thumb .thumb-groups{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px;width:100%}.thumb-group{border:2px solid #d4bc8d;border-radius:17px;box-shadow:0 4px 0 #bea46e33;background:#fff9e8;padding:12px 5px;display:flex;flex-wrap:wrap;justify-content:center;gap:2px}.thumb-group img{width:45px;height:45px;object-fit:contain}.geometry-hub .counting-short-grid{margin:22px 0 30px}.geometry-hub .parent-note{max-width:850px;margin:30px auto}.foundation-start .thumb-groups{display:flex;gap:18px}.foundation-start .thumb-group{width:150px}.foundation-start .thumb-group img{width:57px;height:57px}@keyframes lay-ruler{from{transform:translate(32px,30px);opacity:.3}to{transform:translate(0);opacity:1}}@keyframes group-pop{from{transform:scale(.6);opacity:.4}to{transform:scale(1);opacity:1}}@media(max-width:600px){.foundation-main{padding:10px 12px 30px}.foundation-start{padding:20px 16px}.foundation-hero{height:150px}.foundation-scene{padding:20px 14px;min-height:235px;border-radius:23px}.foundation-scene.shapes{gap:10px;padding:22px 10px}.foundation-main .shape-choice{min-height:133px;padding:4px;border-radius:18px}.shape-choice svg{height:125px}.f-toolbar strong{font-size:.84rem}.foundation-main .f-toolbar button{padding:6px 9px;font-size:.76rem}.f-question-row{min-height:72px}.f-question-row h2{font-size:1.08rem}.foundation-main .number-choice{min-width:80px;min-height:59px;font-size:1.35rem}.f-answers{gap:12px}.foundation-scene.length{padding:22px 14px;gap:15px}.foundation-main .ribbon-choice{padding:14px 8px}.ribbon{height:31px}.group-boxes{gap:14px}.foundation-main .group-bowl,.group-bowl{min-height:105px;padding:10px 6px;border-radius:19px;gap:2px}.group-bowl img{width:38px;height:38px}.group-equation{font-size:1.05rem}.foundation-scene.tutorial.shapes{grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}.tutorial-shape{padding:7px}.tutorial-shape svg{height:95px}.foundation-scene.measure{min-height:210px}.foundation-thumb{height:100%;min-height:260px;flex-direction:column;padding:12px}.foundation-thumb .thumb-groups{grid-template-columns:1fr;width:90px;gap:12px}.thumb-group{padding:8px 5px}.thumb-group img{width:30px;height:30px}.foundation-start .thumb-group{width:110px}.foundation-start .thumb-group img{width:43px;height:43px}.f-hint{font-size:.79rem}}@media(prefers-reduced-motion:reduce){*,*:before,*:after{animation:none!important;transition:none!important}}
@media(max-width:600px){.group-box{padding-top:4px}.foundation-main .group-undo{position:absolute;top:-1px;right:-4px;width:32px;min-height:30px;height:30px;padding:0;margin:0;z-index:2}.foundation-main .group-bowl{min-height:112px;padding:16px 7px 10px}.group-bowl img{width:34px;height:34px}.foundation-scene.multiply{padding:18px 14px}.foundation-scene.multiply .group-boxes{gap:13px}}
.geometry-hub .short-copy p{font-weight:400}.foundation-start .thumb-groups{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));width:100%;max-width:460px;gap:12px}.foundation-start .thumb-group{width:auto;min-width:0}.foundation-hero>svg{width:250px;height:165px}@media(max-width:600px){.foundation-start .thumb-groups{gap:8px}.foundation-start .thumb-group img{width:34px;height:34px}}
.foundation-scene.multiply{min-height:0}.foundation-main .group-bowl:disabled{opacity:1}.foundation-main .f-actions .primary{min-width:135px}
@media(max-width:600px){.group-bowl img{width:48px;height:48px}}