:root{color:#1f2933;background:#f5efe4;font-family:Noto Sans SC,PingFang SC,system-ui,sans-serif}*{box-sizing:border-box}body{min-width:320px;margin:0}button,input,textarea,select{font:inherit}button{color:#3f3427;cursor:pointer;background:#efe3d0;border:0;border-radius:14px;padding:10px 16px;transition:transform .15s,background .15s}button:hover:not(:disabled){background:#e8d7bd;transform:translateY(-1px)}button:disabled{opacity:.5;cursor:not-allowed}button.primary{color:#fff;background:#1f5f3a;box-shadow:0 10px 24px #1f5f3a38}button.active{color:#fff;background:#26211a}input,textarea,select{color:#1f2933;background:#fffaf2;border:1px solid #d8c7aa;border-radius:12px;width:100%;padding:11px 12px}textarea{resize:vertical;min-height:86px}label{color:#544533;gap:8px;font-weight:700;display:grid}main{max-width:1360px;margin:0 auto;padding:28px}.hero{background:linear-gradient(135deg,#fff8ed,#ead7b8);border-radius:32px;grid-template-columns:1fr auto;align-items:end;gap:24px;padding:34px;display:grid;box-shadow:0 24px 80px #53401f1f}.hero h1{letter-spacing:-.06em;margin:4px 0 8px;font-size:clamp(34px,6vw,72px)}.hero p{color:#705f48;max-width:760px;margin:0;line-height:1.8}.hero nav{background:#ffffff8c;border-radius:18px;gap:10px;padding:8px;display:flex}.eyebrow{color:#1f5f3a;text-transform:uppercase;letter-spacing:.12em;margin:0;font-size:12px;font-weight:900}.panel{background:#fffcf6e6;border-radius:30px;margin-top:24px;padding:26px;box-shadow:0 16px 50px #432f1517}.panel-head{justify-content:space-between;align-items:center;gap:20px;margin-bottom:20px;display:flex}.panel-head h2{letter-spacing:-.04em;margin:4px 0 0;font-size:32px}.student-row{align-items:center;gap:10px;display:flex}.student-row input{width:160px}.practice-grid,.editor-grid{grid-template-columns:minmax(360px,680px) 1fr;align-items:start;gap:24px;display:grid}.editor-grid{grid-template-columns:430px minmax(360px,680px)}.board{aspect-ratio:1;background:#c99645;border-radius:22px;width:min(100%,680px);padding:18px;display:grid;box-shadow:inset 0 0 0 10px #b57e31,0 18px 46px #4025052e}.point{appearance:none;background:0 0;border-radius:0;width:100%;min-width:0;height:100%;min-height:0;padding:0;line-height:0;transition:background .12s;display:block;position:relative;overflow:visible}.point:before,.point:after{content:"";pointer-events:none;background:#2c1b079e;position:absolute}.point:before{height:1px;top:50%;left:0;right:0}.point:after{width:1px;top:0;bottom:0;left:50%}.board .point:hover:not(:disabled){background:#ffffff1f;transform:none}.star{z-index:1;background:#3a260d;border-radius:50%;width:7px;height:7px;position:absolute;top:calc(50% - 3.5px);left:calc(50% - 3.5px)}.stone{z-index:2;border-radius:999px;place-items:center;width:88%;height:88%;font-size:clamp(8px,1.25vw,15px);font-weight:800;display:grid;position:absolute;top:6%;left:6%}.stone.black{color:#fff;background:radial-gradient(circle at 35% 25%,#5b5b5b,#080808 62%);box-shadow:0 4px 8px #0006}.stone.white{color:#202020;background:radial-gradient(circle at 35% 25%,#fff,#d9d4ca 72%);box-shadow:0 4px 8px #0000003d}.practice-side,.form-card{background:#fff8ed;border:1px solid #ead9be;border-radius:24px;padding:22px}.practice-side h3{margin:16px 0 6px;font-size:28px}.practice-side p{color:#75644d;line-height:1.7}.pill{color:#1f5f3a;background:#e6f0e9;border-radius:999px;padding:6px 12px;font-weight:800;display:inline-flex}.next-color{background:#efe3d0;border-radius:14px;padding:12px 14px;font-weight:900}.steps{min-height:110px;padding-left:20px;line-height:1.9}.actions,.mode-row,.answer-tabs,.color-picker{flex-wrap:wrap;gap:10px;display:flex}.color-tools{gap:10px;display:grid}.color-picker{background:#fbefd9;border-radius:16px;align-items:center;padding:10px}.color-picker span{color:#544533;font-weight:900}.result{border-radius:16px;margin-top:14px;padding:14px;font-weight:900}.result.ok{color:#1f6f43;background:#e6f4ea}.result.bad{color:#a33b1f;background:#fee8e0}.video{background:#000;border-radius:18px;width:100%;margin-top:14px}.wide{width:100%;margin-top:12px}.empty{color:#75644d;text-align:center;background:#fff8ed;border-radius:22px;padding:40px}.form-card{gap:16px;display:grid}.hint{color:#75644d;margin:0;line-height:1.6}.problem-list{margin-top:22px}.problem-list h3{margin:0 0 12px}.problem-item{background:#fff8ed;border:1px solid #ead9be;border-radius:16px;justify-content:space-between;gap:16px;margin-bottom:10px;padding:14px 16px;display:flex}.problem-item span{color:#75644d}@media (width<=900px){main{padding:14px}.hero,.practice-grid,.editor-grid{grid-template-columns:1fr}.hero nav,.panel-head,.student-row{flex-direction:column;align-items:stretch}.panel{padding:16px}}