@import url('https://fonts.googleapis.com/css2?family=DM+Sans:wght@400;500;600;700&family=Noto+Sans+JP:wght@400;500;600;700;800&display=swap');
.field select{width:100%;border:1px solid #dce8de;border-radius:10px;padding:13px;background:#fff;color:#243d30;font:inherit;font-weight:400}
:root{font-family:'DM Sans','Noto Sans JP',-apple-system,BlinkMacSystemFont,sans-serif;color:#263d31;background:#f6f8f5;font-size:14px}*{box-sizing:border-box}body{margin:0}button,input,textarea{font:inherit}button{cursor:pointer}button:focus-visible,input:focus-visible,textarea:focus-visible{outline:3px solid #9bcdb1;outline-offset:2px}button:disabled{opacity:.55;cursor:wait}.shell{max-width:1440px;margin:auto;min-height:100vh;display:grid;grid-template-columns:225px 1fr}.side{background:#fff;border-right:1px solid #e5ece6;padding:28px 16px;display:flex;flex-direction:column;gap:10px}.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:#234233;font-weight:800;font-size:16px;margin:0 4px 38px}.brand img{width:38px}.brand small{display:block;font-size:9px;letter-spacing:.08em;color:#9aaba0;margin-top:3px}.nav-label,.eyebrow{color:#8ca093;font-size:10px;letter-spacing:.14em;font-weight:800}.side button{border:0;border-radius:10px;background:transparent;padding:13px;text-align:left;color:#72877a;font-weight:700}.side button.active{background:#eaf4ed;color:#286a50}.side .identity{margin-top:auto;border-top:1px solid #edf1ed;padding:20px 6px 0;font-size:12px;line-height:1.7}.side .identity span{display:block;color:#9aa99f;font-size:11px}.main{min-width:0}.top{height:72px;background:#fff;border-bottom:1px solid #e8eee8;padding:0 6%;display:flex;justify-content:space-between;align-items:center;color:#86988b;font-size:12px}.content{padding:40px 6% 80px;max-width:1250px;margin:auto}.head{display:flex;align-items:flex-end;justify-content:space-between;gap:16px;margin-bottom:25px}.head h1{font-size:26px;margin:8px 0}.head p,.muted{color:#829388;line-height:1.7}.head p{margin:0;font-size:13px}.hero{padding:26px 30px;border-radius:18px;background:#e5f1e7;display:flex;justify-content:space-between;gap:20px;align-items:center}.hero h2{font-size:21px;line-height:1.5;margin:7px 0}.hero p{font-size:12px;color:#6e8976;line-height:1.8;margin:0}.hero-mark{font-size:85px;color:#c4dfcb;line-height:1}.section-title{margin:30px 0 14px;display:flex;justify-content:space-between;align-items:center}.section-title h2{font-size:16px;margin:0}.card{background:#fff;border:1px solid #e9efea;border-radius:16px;padding:22px;box-shadow:0 4px 20px #29453306}.grid{display:grid;grid-template-columns:1fr 1fr;gap:16px}.stats{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin:18px 0}.stat{background:white;border:1px solid #ebf0eb;border-radius:14px;padding:19px}.stat small{color:#8c9e92;font-size:11px}.stat strong{display:block;font-size:27px;margin-top:10px}.btn{border:0;border-radius:10px;background:#286b51;color:white;padding:13px 18px;font-weight:700;min-height:44px}.btn:hover{background:#1e5740}.btn.light{background:#edf5ef;color:#326b4e}.btn.outline{background:#fff;color:#326b4e;border:1px solid #dce9de}.btn.small{font-size:12px;padding:8px 12px;min-height:36px}.btn.danger{background:#fbefea;color:#ad6d50}.field{display:grid;gap:8px;margin:15px 0;color:#536c5b;font-weight:700;font-size:12px}.field input,.field textarea,.field select{width:100%;border:1px solid #dce8de;border-radius:10px;padding:13px;background:#fff;color:#243d30;font-weight:400}.field textarea{min-height:105px;resize:vertical;line-height:1.7}.field small{font-weight:400;color:#98a99d}.drop{border:1.5px dashed #bad3bf;background:#f8fcf8;border-radius:14px;padding:30px 18px;text-align:center;line-height:1.9;color:#63826d;display:block}.drop strong{display:block;color:#355d45}.drop-icon{font-size:28px}.notice{border-radius:12px;padding:15px 17px;background:#fff8e7;color:#876f40;line-height:1.7;font-size:12px}.empty{text-align:center;padding:40px 15px;color:#9aac9f;line-height:1.8}.empty strong{display:block;color:#5e7666}.row{display:flex;align-items:center;gap:13px;padding:15px 0;border-bottom:1px solid #edf1ed}.row:last-child{border-bottom:0}.row .avatar{flex:none;width:38px;height:38px;display:grid;place-items:center;border-radius:50%;background:#eaf4eb;color:#4c8560;font-weight:700}.row .grow{flex:1;min-width:0}.row strong{display:block}.row small{display:block;margin-top:5px;color:#97a79c}.badge{display:inline-block;border-radius:20px;padding:6px 10px;background:#eaf4ec;color:#588b68;font-size:10px;font-weight:700}.badge.pending{background:#fff5df;color:#a17a3e}.stack{display:grid;gap:16px}.preview{max-width:100%;display:block;border-radius:10px;background:#f1f4f1}.math{line-height:1.9;overflow-wrap:anywhere;white-space:pre-wrap}.math .katex-display{overflow-x:auto;overflow-y:hidden}.image-wrap{position:relative;display:inline-block;max-width:100%;line-height:0}.image-wrap img{max-width:100%;max-height:560px;display:block;border-radius:10px}.highlight{position:absolute;border:3px solid #df7853;border-radius:4px;background:#f58f6533;pointer-events:none}.feedback{background:#eef7ef;border-radius:13px;padding:18px;color:#365f45;line-height:1.8}.chat{max-height:280px;overflow:auto;display:grid;gap:10px;margin:12px 0}.bubble{padding:11px 14px;border-radius:12px;background:#f2f5f1;white-space:pre-wrap;line-height:1.6}.bubble.teacher{background:#e9f3eb;margin-left:15%}.bubble.assistant{margin-right:10%}.login{min-height:100vh;display:grid;place-items:center;padding:24px;background:radial-gradient(circle at 80% 10%,#dceee0,#f8faf7 45%)}.login-card{background:white;border:1px solid #e7eee8;border-radius:22px;max-width:470px;width:100%;padding:38px;box-shadow:0 16px 45px #234c3010}.login-card .brand{margin-bottom:34px}.login h1{font-size:26px;line-height:1.5}.login p{line-height:1.8;color:#83968a}.login .notice{margin-top:24px}.tools{display:flex;gap:8px;flex-wrap:wrap}.back{border:0;background:transparent;padding:0;color:#558568;font-weight:700;margin-bottom:18px}#toast{position:fixed;bottom:25px;left:50%;transform:translate(-50%,15px);padding:12px 18px;background:#274d39;color:white;border-radius:9px;opacity:0;transition:.2s;pointer-events:none;z-index:20;max-width:90%;font-size:12px}#toast.show{opacity:1;transform:translate(-50%,0)}.hidden{display:none!important}@media(max-width:760px){.shell{display:block}.side{position:sticky;top:0;z-index:5;display:flex;flex-direction:row;align-items:center;padding:10px 4%;gap:6px;border-right:0;border-bottom:1px solid #e5ece6;overflow:auto}.side .brand{margin:0 auto 0 0;white-space:nowrap;font-size:13px}.brand img{width:32px}.brand small,.side .nav-label,.side .identity{display:none}.side button{padding:10px;white-space:nowrap;font-size:11px}.top{height:42px;padding:0 5%}.content{padding:26px 5% 70px}.head h1{font-size:22px}.head{align-items:start}.head .btn{font-size:11px;padding:10px}.hero{padding:20px}.hero h2{font-size:17px}.hero-mark{font-size:45px}.grid{grid-template-columns:1fr}.stats{gap:8px}.stat{padding:14px}.stat strong{font-size:23px}.card{padding:18px}.login-card{padding:28px}.row .badge{display:none}}