:root{--navy: #13213f;--red: #ce1124;--bg: #f3f6fc;--ink: #13213f;--muted: #6b7590;--line: rgba(13, 33, 63, .1);--card: #ffffff}*{box-sizing:border-box}html,body,#root{height:100%;margin:0}body{font-family:Hanken Grotesk,system-ui,-apple-system,sans-serif;background:var(--bg);color:var(--ink);-webkit-font-smoothing:antialiased}button{font-family:inherit;cursor:pointer}.muted{color:var(--muted)}.small{font-size:12.5px}.pad{padding:14px 16px}.center{height:100%;display:flex;align-items:center;justify-content:center;padding:24px}.brand{font-weight:800;font-size:22px;letter-spacing:.01em}.brand.small{font-size:18px}.brand span{color:var(--red)}.brand-sub{font-size:11px;letter-spacing:.18em;text-transform:uppercase;color:var(--muted);margin:4px 0 22px}.tag{font-size:10px;letter-spacing:.14em;text-transform:uppercase;background:var(--navy);color:#fff;padding:2px 7px;border-radius:5px;vertical-align:middle}.login-card{width:340px;max-width:100%;background:var(--card);border:1px solid var(--line);border-radius:18px;padding:30px 28px;box-shadow:0 30px 70px -40px #0d213f73;display:flex;flex-direction:column}.login-card label{display:flex;flex-direction:column;gap:6px;font-size:13px;font-weight:600;color:#3e4768;margin-bottom:14px}.login-card input{padding:11px 12px;border:1px solid var(--line);border-radius:10px;font-size:15px;outline:none}.login-card input:focus{border-color:var(--red)}.login-card button[type=submit]{background:var(--red);color:#fff;font-weight:700;font-size:15px;border:none;padding:12px;border-radius:999px;margin-top:4px}.login-card button[disabled]{opacity:.6}.login-card .muted{margin-top:14px;text-align:center}.error{color:#b91c1c;background:#fef2f2;border:1px solid #fecaca;padding:9px 11px;border-radius:9px;font-size:13.5px;margin-bottom:12px}.shell{height:100%;display:flex;flex-direction:column}.topbar{height:58px;flex:none;background:var(--card);border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;padding:0 20px}.topbar-right{display:flex;align-items:center;gap:14px}.ghost{background:transparent;border:1px solid var(--line);color:var(--ink);padding:7px 14px;border-radius:999px;font-weight:600;font-size:13.5px}.cols{flex:1;display:flex;min-height:0}.sidebar{width:320px;flex:none;background:var(--card);border-right:1px solid var(--line);display:flex;flex-direction:column;min-height:0}.sidebar-head{padding:14px 16px;font-weight:700;font-size:14px;border-bottom:1px solid var(--line);display:flex;align-items:center;gap:8px}.count{background:var(--bg);color:var(--muted);font-size:12px;padding:1px 8px;border-radius:999px}.student-list{list-style:none;margin:0;padding:0;overflow-y:auto}.student-list li{display:flex;align-items:center;gap:12px;padding:11px 16px;border-bottom:1px solid var(--line);cursor:pointer}.student-list li:hover{background:#f8faff}.student-list li.active{background:#eef3ff}.avatar{width:40px;height:40px;border-radius:50%;flex:none;background:#e7edf8;color:var(--red);font-weight:700;display:grid;place-items:center}.student-meta{min-width:0}.student-name{font-weight:600;font-size:14.5px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.student-sub{font-size:12.5px}.thread-pane{flex:1;min-height:0;display:flex;flex-direction:column}.live-dot{width:8px;height:8px;border-radius:50%;background:#22c55e;flex:none;box-shadow:0 0 0 3px #22c55e2e}.detail-shell{height:100%;display:flex;flex-direction:column;min-height:0}.detail-head{flex:none;display:flex;align-items:center;justify-content:space-between;padding:14px 20px;border-bottom:1px solid var(--line);background:var(--card)}.detail-name{font-weight:700;font-size:15.5px}.detail-body{flex:1;min-height:0;display:flex;flex-direction:column}.tabs{display:flex;gap:6px;background:var(--bg);padding:3px;border-radius:999px}.tab{border:none;background:transparent;color:var(--muted);font-weight:600;font-size:13px;padding:7px 16px;border-radius:999px}.tab.active{background:var(--navy);color:#fff}.thread-scroll{flex:1;min-height:0;overflow-y:auto;padding:20px;display:flex;flex-direction:column;gap:10px;background:var(--bg)}.bubble-row{display:flex}.bubble-row.left{justify-content:flex-start}.bubble-row.right{justify-content:flex-end}.bubble-row.center{justify-content:center}.bubble{max-width:62%;padding:10px 14px;border-radius:14px;font-size:14px;line-height:1.45;box-shadow:0 6px 18px -14px #0d213f80}.bubble-left{background:#fff;color:var(--ink);border-bottom-left-radius:4px}.bubble-right{background:var(--red);color:#fff;border-bottom-right-radius:4px}.bubble-tag{font-size:10.5px;font-weight:700;letter-spacing:.04em;text-transform:uppercase;opacity:.65;margin-bottom:3px}.bubble-right .bubble-tag{opacity:.85}.bubble-text{white-space:pre-wrap;word-break:break-word}.bubble-ts{font-size:10.5px;opacity:.6;margin-top:5px;text-align:right}.tips-card{max-width:78%;background:#fff7ec;border:1px solid #f2d9ad;border-radius:14px;padding:12px 16px;font-size:13.5px}.tips-head{font-weight:700;margin-bottom:8px}.tips-grid{display:grid;grid-template-columns:1fr 1fr;gap:6px 16px;margin-bottom:6px}.tips-grid .muted{font-size:12px;margin-right:4px}.tips-notes{font-style:italic;color:var(--muted);margin-top:4px}.cost-tab{flex:1;min-height:0;overflow-y:auto;padding:20px}.stat-tiles{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin-bottom:20px}.stat-tile{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:14px 16px}.stat-value{font-size:20px;font-weight:800;color:var(--navy)}.stat-label{font-size:12px;color:var(--muted);margin-top:4px}.chart-wrap{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:14px 8px;margin-bottom:14px}.cost-note{padding:0 4px}