:root{--brand: #7C5CC4;--brand-dark: #5E3FA8;--brand-soft: #F1ECFA;--ink: #2A2340;--muted: #6E6787;--line: #E4DDF2;--bg: #FAF8FE;--ok: #2E9D5B;--ok-soft: #E6F6EC;--err: #D64545;--err-soft: #FDECEC;--radius: 14px;--han: "LXGW WenKai TC", "Noto Serif SC", serif}*{box-sizing:border-box}html,body{margin:0;padding:0}body{font-family:system-ui,-apple-system,Segoe UI,Roboto,Helvetica Neue,Arial,sans-serif;font-size:17px;line-height:1.5;color:var(--ink);background:var(--bg)}.app{min-height:100vh;display:flex;flex-direction:column}.topbar{background:var(--brand);color:#fff;padding:12px 16px;display:flex;align-items:center;justify-content:space-between;gap:12px}.topbar .brand{font-weight:700;font-size:18px}.topbar .sub{font-size:14px;opacity:.85}.topbar button{background:#ffffff29;color:#fff;border:0}.container{width:100%;max-width:960px;margin:0 auto;padding:16px;flex:1}.card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:18px;margin-bottom:16px}.card h2{margin:0 0 12px;font-size:20px}.card h3{margin:0 0 8px;font-size:18px}.center-box{max-width:420px;margin:40px auto}label{display:block;font-weight:600;margin:12px 0 6px;font-size:16px}input,textarea,select{width:100%;font:inherit;padding:11px 12px;border:1px solid var(--line);border-radius:10px;background:#fff;color:var(--ink)}input:focus,textarea:focus,select:focus{outline:2px solid var(--brand);border-color:var(--brand)}input.code{text-transform:uppercase;letter-spacing:2px;font-size:20px;text-align:center}textarea{min-height:70px;resize:vertical}button{font:inherit;font-weight:600;border:0;border-radius:10px;padding:10px 16px;cursor:pointer;background:var(--brand-soft);color:var(--brand-dark)}button.primary{background:var(--brand);color:#fff}button.primary:hover{background:var(--brand-dark)}button.danger{background:var(--err-soft);color:var(--err)}button.small{padding:6px 10px;font-size:14px}button:disabled{opacity:.55;cursor:default}.btn-full{width:100%;margin-top:16px;padding:13px}.row{display:flex;gap:10px;align-items:center;flex-wrap:wrap}.row>.grow{flex:1;min-width:160px}.spacer{flex:1}.msg{padding:10px 12px;border-radius:10px;margin-top:12px;font-size:15px}.msg.err{background:var(--err-soft);color:var(--err)}.msg.ok{background:var(--ok-soft);color:var(--ok)}.muted{color:var(--muted);font-size:15px}.tabs{display:flex;gap:6px;margin-bottom:16px;flex-wrap:wrap}.tabs button{background:#fff;border:1px solid var(--line);color:var(--muted)}.tabs button.active{background:var(--brand);color:#fff;border-color:var(--brand)}table{width:100%;border-collapse:collapse;font-size:15px}th,td{text-align:left;padding:9px 8px;border-bottom:1px solid var(--line);vertical-align:top}th{color:var(--muted);font-weight:600;font-size:14px}.table-wrap{overflow-x:auto}.pill{display:inline-block;padding:2px 9px;border-radius:999px;background:var(--brand-soft);color:var(--brand-dark);font-size:13px;font-weight:600;margin:1px 3px 1px 0}.mono{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;letter-spacing:.5px}.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:10px}.lesson{background:#fff;border:1px solid var(--line);border-radius:12px;padding:14px;text-align:left;color:var(--ink);font-weight:500}.lesson .num{font-size:13px;color:var(--muted)}.lesson .han{font-family:var(--han);font-size:26px;color:var(--brand-dark)}.lesson.soon{opacity:.6}.level-tabs{display:flex;gap:8px;overflow-x:auto;padding-bottom:4px;margin-bottom:14px}.level-tabs button{white-space:nowrap}.level-tabs button.active{background:var(--brand);color:#fff}.new-student{background:var(--brand-soft);border-radius:10px;padding:10px;margin-top:8px}.new-student input,.new-student select{padding:8px 10px}.footer{text-align:center;color:var(--muted);font-size:13px;padding:16px}