:root{--bg:#f6f7f9;--card:#fff;--text:#17202a;--muted:#68707b;--line:#e3e7eb;--primary:#1f5eff;--ok:#18794e;--warn:#9a6700;--danger:#b42318}*{box-sizing:border-box}body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,Arial,sans-serif;background:var(--bg);color:var(--text)}a{color:inherit;text-decoration:none}.wrap{width:min(1160px,calc(100% - 28px));margin:auto}.topbar{background:#fff;border-bottom:1px solid var(--line);position:sticky;top:0;z-index:10}.topbar-inner{min-height:62px;display:flex;align-items:center;justify-content:space-between;gap:20px}.brand{font-weight:800}.topbar nav{display:flex;gap:16px;font-size:14px}main.wrap{padding:28px 0 60px}.hero,.card{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:28px}.hero{text-align:center;padding:64px 28px}.narrow{max-width:470px;margin:40px auto}.card h1,.card h2,.hero h1{margin-top:0}label{display:block;font-weight:650;margin:14px 0}input,select{width:100%;margin-top:7px;border:1px solid #cfd5dc;border-radius:10px;padding:11px 12px;font:inherit;background:#fff}.btn{display:inline-flex;align-items:center;justify-content:center;border:1px solid #cfd5dc;border-radius:10px;padding:10px 15px;background:#fff;cursor:pointer;font-weight:700;font:inherit}.btn.primary{background:var(--primary);border-color:var(--primary);color:#fff}.btn.small{padding:7px 10px;font-size:13px}.wide{width:100%}.actions{display:flex;gap:10px;flex-wrap:wrap}.flash{padding:12px 14px;border-radius:10px;margin-bottom:16px}.flash.ok{background:#eaf7f0;color:var(--ok)}.flash.error{background:#fff0ef;color:var(--danger)}.student-head,.section-title,.toolbar{display:flex;align-items:center;justify-content:space-between;gap:18px;margin-bottom:20px}.student-head h1,.section-title h1{margin:0}.student-head p,.section-title p{margin:5px 0 0;color:var(--muted)}.badge{display:inline-block;border-radius:999px;padding:5px 9px;font-size:12px;font-weight:800;white-space:nowrap}.badge.ok{background:#eaf7f0;color:var(--ok)}.badge.warn{background:#fff5d8;color:var(--warn)}.activity-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}.activity-card{background:#fff;border:1px solid var(--line);border-radius:14px;padding:18px}.activity-top{display:flex;justify-content:space-between;gap:8px}.activity-card h3{margin:0}.activity-card p{color:var(--muted);font-size:14px}.activity-form{border-top:1px solid var(--line);margin-top:14px;padding-top:8px}.activity-form label{font-weight:500;font-size:14px}.activity-form input[type=radio]{width:auto;margin-right:8px}.hidden{display:none!important}.muted{color:var(--muted)}.stats{display:flex;gap:8px;flex-wrap:wrap}.stats span{background:#fff;border:1px solid var(--line);padding:8px 10px;border-radius:10px;font-size:13px}.toolbar{background:#fff;border:1px solid var(--line);border-radius:12px;padding:10px}.toolbar form{display:flex;gap:8px;align-items:center}.toolbar select,.toolbar input{margin:0;width:auto}.table-wrap{overflow:auto;background:#fff;border:1px solid var(--line);border-radius:14px}table{width:100%;border-collapse:collapse;min-width:720px}th,td{text-align:left;padding:12px 14px;border-bottom:1px solid var(--line);font-size:14px}th{background:#fafbfc;font-size:12px;text-transform:uppercase;letter-spacing:.04em;color:var(--muted)}tr.enrolled{background:#fbfffc}.mono{font-family:ui-monospace,SFMono-Regular,Menlo,monospace}.linkbtn{border:0;background:none;color:var(--primary);cursor:pointer;padding:0}.two-col{display:grid;grid-template-columns:1fr 1.4fr;gap:18px}.row{display:grid;grid-template-columns:1fr 1fr;gap:12px}.list-item{display:flex;justify-content:space-between;gap:12px;align-items:center;padding:13px 0;border-bottom:1px solid var(--line)}.list-item small{display:block;color:var(--muted);margin-top:4px}
@media(max-width:900px){.activity-grid{grid-template-columns:repeat(2,1fr)}.two-col{grid-template-columns:1fr}.topbar nav{gap:9px;font-size:12px}}
@media(max-width:620px){.wrap{width:min(100% - 20px,1160px)}main.wrap{padding-top:18px}.topbar-inner{align-items:flex-start;padding:12px 0;flex-direction:column}.topbar nav{width:100%;overflow:auto;padding-bottom:2px}.hero{padding:40px 18px}.card{padding:20px}.activity-grid{grid-template-columns:1fr 1fr;gap:9px}.activity-card{padding:13px}.activity-card h3{font-size:16px}.student-head,.section-title{align-items:flex-start;flex-direction:column}.toolbar{align-items:stretch;flex-direction:column}.toolbar form{width:100%}.toolbar select,.toolbar input{width:100%}.row{grid-template-columns:1fr}.stats{width:100%}.stats span{flex:1}.btn{min-height:42px}.activity-form .actions{flex-direction:column}.activity-form .actions .btn{width:100%}}
@media(max-width:390px){.activity-grid{grid-template-columns:1fr}}