:root{
  --bg:#0b1222;--panel:#0f172a;--muted:#94a3b8;--text:#e5e7eb;
  --accent:#4f46e5;--accent-2:#6366f1;--border:#1f2937;
  --bad:#ef4444;--ok:#10b981;
  --card-grad: linear-gradient(180deg,rgba(255,255,255,.06),rgba(255,255,255,.03));
  --shadow: 0 10px 30px rgba(0,0,0,.25);
  --radius:16px;
}
*{box-sizing:border-box} html,body{height:100%}
body{margin:0;font-family:Inter,system-ui,-apple-system,Segoe UI,Roboto,Ubuntu,Cantarell,Noto Sans,sans-serif;background:radial-gradient(1200px 800px at 70% -10%,#1e293b 0,#0b1222 45%,#000 100%);color:var(--text)}
.wrap{max-width:1100px;margin:32px auto;padding:0 18px}
h1{margin:0 0 8px;font-weight:800} p{color:var(--muted);margin:0 0 16px}
.card{background:var(--card-grad);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow)}
.section{padding:16px} .hint{color:var(--muted);font-size:12px;margin-top:-6px;padding:0 18px 12px}

/* Topbar */
.topbar{display:none;align-items:center;justify-content:space-between;gap:12px;background:var(--card-grad);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);padding:12px 16px;margin-bottom:16px}
.me{color:var(--muted);font-size:14px}
.btn-ghost{padding:10px 12px;border-radius:10px;border:1px solid var(--border);background:#0b1020;color:#e5e7eb;cursor:pointer;text-decoration:none;display:inline-block}
.btn-ghost:hover{outline:2px solid var(--accent)}
.btn-ghost.primary{border-color:#4338ca;box-shadow:inset 0 0 0 1px #4338ca}

/* Form */
form{display:grid;gap:12px;padding:18px} label{font-size:14px;color:var(--muted)}
input,button{width:100%;padding:12px 14px;border-radius:12px;border:1px solid var(--border);background:#0b1020;color:#e5e7eb}
input:focus{outline:2px solid var(--accent);border-color:var(--accent)} .row{display:grid;grid-template-columns:1fr;gap:12px}
@media (min-width:640px){.row{grid-template-columns:1fr 1fr}}
.btn{cursor:pointer;background:linear-gradient(90deg,#4338ca,var(--accent),var(--accent-2));border:none;font-weight:700;text-decoration:none;text-align:center;display:inline-block}
.btn:disabled{opacity:.6;cursor:not-allowed}
.status{padding:12px 18px;border-top:1px solid var(--border);font-size:14px} .ok{color:var(--ok)} .bad{color:var(--bad)}

/* Viewer */
.viewer-wrap{display:none;gap:16px;margin-top:16px}
@media (min-width:900px){.viewer-wrap{grid-template-columns: 320px 1fr}}
.side{background:var(--card-grad);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);padding:12px}
.side h3{margin:4px 8px 10px;font-size:14px;color:var(--muted);font-weight:700}
.search{width:100%;padding:10px 12px;border-radius:10px;border:1px solid var(--border);background:#0b1020;color:#e5e7eb;margin:0 6px 10px}
.list{max-height:520px;overflow:auto;padding:4px}
.item{padding:10px 12px;border-radius:12px;border:1px solid var(--border);background:#0b1020;cursor:pointer;margin:8px;transition:background .15s,transform .05s}
.item:hover{background:#121733} .item.active{outline:2px solid var(--accent);background:#151c3a}
.i-title{font-weight:800;font-size:14px}
.i-sub{font-size:12px;color:var(--muted);margin-top:4px;display:flex;justify-content:space-between;gap:8px}
.badge{background:rgba(34,197,94,.15);border:1px solid rgba(34,197,94,.25);color:#34d399;border-radius:999px;padding:2px 8px;font-size:11px;font-weight:800}
.main{background:var(--card-grad);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);padding:16px}
.main .head{display:flex;justify-content:space-between;align-items:center;gap:12px;flex-wrap:wrap}
.main .title{font-weight:800;font-size:18px} .main .meta{color:var(--muted);font-size:12px}
.cards{margin-top:12px;display:grid;gap:12px} @media (min-width:720px){.cards{grid-template-columns: 1fr 1fr}}
.card-grade{background:#0b1020;border:1px solid var(--border);border-radius:14px;padding:14px}
.cg-top{display:flex;align-items:center;justify-content:space-between;margin-bottom:8px}
.cg-chip{font-size:11px;font-weight:800;padding:6px 10px;border-radius:999px;color:#fff;background:linear-gradient(135deg,#06b6d4,#0ea5e9)}
.cg-chip.quiz{background:linear-gradient(135deg,#22c55e,#16a34a)} .score{font-size:24px;font-weight:900}
.excellent{color:#16a34a} .good{color:#0ea5e9} .avg{color:#f59e0b} .poor{color:#ef4444}
.cg-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:10px}
.kv{border:1px dashed var(--border);border-radius:10px;padding:10px}
.k{font-size:11px;color:var(--muted);text-transform:uppercase;letter-spacing:.3px} .v{font-size:14px;font-weight:600}
.note{margin-top:10px;padding-top:10px;border-top:1px dashed var(--border);font-size:13px}

/* Flash (center notify) */
.flash-backdrop{position:fixed; inset:0; display:none; align-items:center; justify-content:center;background:rgba(0,0,0,.45); z-index:99999}
.flash{width:min(560px,92vw); background:linear-gradient(180deg,rgba(15,23,42,.95),rgba(15,23,42,.98));border:1px solid rgba(255,255,255,.1);border-radius:24px;box-shadow:0 20px 60px rgba(0,0,0,.4);padding:32px;text-align:center;transform:scale(.95);opacity:0;transition:transform .2s,opacity .2s}
.flash.show{transform:scale(1);opacity:1}
.flash h3{margin:0 0 8px;font-size:24px;font-weight:800}
.flash p{font-size:16px;margin:0;color:var(--muted)}
.flash.info h3{color:#0ea5e9} .flash.success h3{color:#10b981} .flash.error h3{color:#ef4444} .flash.warning h3{color:#f59e0b}

/* Toast nổi (P/s) */
.toast-wrap{position:fixed;top:20px;right:20px;z-index:9999;display:flex;flex-direction:column;gap:10px;max-width:360px}
.toast{display:flex;align-items:center;gap:12px;background:var(--card-grad);border:1px solid var(--border);border-radius:14px;box-shadow:0 10px 30px rgba(0,0,0,.3);padding:14px 16px;animation:toastIn .3s ease-out}
@keyframes toastIn{from{transform:translateX(100%);opacity:0} to{transform:translateX(0);opacity:1}}
.toast .icon{font-size:18px;flex-shrink:0}
.toast .content{flex:1;font-size:14px;line-height:1.4}
.toast .close{background:none;border:none;color:var(--muted);font-size:20px;cursor:pointer;padding:0;width:24px;height:24px;display:flex;align-items:center;justify-content:center;border-radius:6px}
.toast .close:hover{background:rgba(255,255,255,.1);color:#fff}

/* Auto-card */
.auto-card{margin:24px 18px;padding:20px;background:rgba(30,41,59,.4);border:1px solid rgba(255,255,255,.1);border-radius:16px}
.auto-card h3{margin:0 0 10px;font-size:18px;font-weight:800}
.pill{display:inline-block;background:rgba(34,197,94,.15);border:1px solid rgba(34,197,94,.25);color:#34d399;border-radius:999px;padding:6px 12px;font-size:12px;font-weight:800;margin-bottom:16px}
.steps{padding-left:20px;margin:16px 0} .steps li{margin:8px 0;font-size:14px}
.actions{margin-top:16px;text-align:center}

/* Community */
.community{margin:20px 18px;padding:20px;background:rgba(79,70,229,.1);border:1px solid rgba(79,70,229,.3);border-radius:16px;text-align:center}
.community h3{margin:0 0 8px;font-size:18px;font-weight:800}
.community p{margin:0 0 16px;font-size:14px}