:root{--ink:#183347;--muted:#66788b;--teal:#087b7d;--bg:#f4f7fa;--line:#dde5eb}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.6 system-ui,sans-serif}a{color:var(--teal)}.top{display:flex;align-items:center;flex-wrap:wrap;gap:24px;padding:20px 5%;background:white;border-bottom:1px solid var(--line)}.brand{font-size:24px;font-weight:800;text-decoration:none;color:var(--ink)}.tag{font-size:13px;color:var(--muted)}nav{margin-left:auto;display:flex;align-items:center;flex-wrap:wrap;gap:18px}nav a{text-decoration:none;font-weight:600}nav form{margin:0}.shell{max-width:1200px;margin:42px auto;padding:0 24px}h1{font-size:clamp(30px,4vw,46px);line-height:1.2;letter-spacing:-1.5px;margin:12px 0 20px}h2{font-size:23px;line-height:1.3}.eyebrow{color:var(--teal);letter-spacing:2px;font-size:12px;font-weight:800}.lead{font-size:19px;color:var(--muted);max-width:700px}.muted,small{color:var(--muted)}small{display:block;margin:8px 0}.card{background:white;border:1px solid var(--line);border-radius:18px;padding:26px;margin-bottom:22px;box-shadow:0 6px 22px #18334705}.login-grid{display:grid;grid-template-columns:1.2fr 1fr;gap:64px;margin-top:60px}.login-grid>.card{max-width:480px}.note,.success,.error{border-radius:12px;padding:18px;margin:22px 0}.note,.success{background:#e4f3f0;color:#215c58}.error{background:#fff0ee;color:#96392f}.page-head{display:flex;align-items:center;justify-content:space-between;gap:20px}.exercise-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px}.exercise{margin:0}.row{display:flex;flex-wrap:wrap;gap:12px;justify-content:space-between;font-size:13px}.badge{background:#edf4fa;border-radius:30px;padding:3px 10px}.actions{display:flex;flex-wrap:wrap;align-items:center;gap:10px}.actions form{margin:0}label{display:block;font-weight:600;margin:16px 0}input,textarea,select{display:block;width:100%;margin-top:6px;padding:12px;background:#fbfcfe;border:1px solid #bdcbd7;border-radius:9px;font:inherit;color:var(--ink)}textarea{font:14px/1.5 ui-monospace,monospace;resize:vertical}button,.button{display:inline-block;padding:11px 18px;background:var(--teal);border:1px solid transparent;border-radius:9px;color:white;font:600 14px/1.5 system-ui,sans-serif;cursor:pointer;text-decoration:none}.secondary{background:#edf4f7;color:var(--ink);border-color:#d7e1e8}.danger{background:#fff2f0;color:#973c34}.subtle{background:transparent;color:var(--muted)}button:hover,.button:hover{filter:brightness(.94)}:focus-visible{outline:3px solid #39b8ae;outline-offset:3px}hr{border:0;border-top:1px solid var(--line);margin:26px 0}.editor-grid{display:grid;grid-template-columns:minmax(0,2fr) minmax(0,1fr);gap:26px}pre{font-size:12px;white-space:pre-wrap;overflow-wrap:anywhere}code{font-size:13px}.preview{width:100%;min-height:520px;border:1px solid var(--line);border-radius:16px;background:white;margin-bottom:24px}.inline{display:flex;align-items:end;gap:16px}.inline label{flex:1;margin:0}.table-wrap{overflow:auto;border:1px solid var(--line);border-radius:14px;background:white}table{border-collapse:collapse;width:100%;text-align:left}td,th{padding:16px;border-bottom:1px solid var(--line)}footer{text-align:center;padding:40px 24px;font-size:13px;color:var(--muted)}.empty{text-align:center;padding:50px}@media(max-width:760px){.top{gap:10px}.tag{display:none}nav{margin:0;width:100%;gap:12px;font-size:13px}.shell{padding:0 16px;margin-top:28px}.login-grid,.editor-grid,.exercise-grid{grid-template-columns:1fr;gap:20px}.login-grid{margin-top:0}.login-grid>.card{max-width:none}.page-head,.inline{align-items:start;flex-direction:column}.inline label{width:100%}.card{padding:20px}}