:root{--bg: #0b0f1a;--bg2: #10162a;--bg3: #161e38;--panel: #121a30;--panel2: #1a2340;--border: #232d4d;--border2: #2e3a61;--text: #e6ebf7;--text2: #9aa6c6;--text3: #6b7699;--accent: #6366f1;--accent2: #22d3ee;--green: #34d399;--red: #f87171;--amber: #fbbf24;--blue: #60a5fa;--purple: #a78bfa;--radius: 14px;--radius-sm: 9px;--shadow: 0 10px 30px rgba(0, 0, 0, .35);--font: "Segoe UI", system-ui, -apple-system, Roboto, "Helvetica Neue", Arial, sans-serif}*{box-sizing:border-box;margin:0;padding:0}html,body,#root{height:100%}body{font-family:var(--font);background:radial-gradient(1200px 600px at 80% -10%,rgba(99,102,241,.14),transparent 60%),radial-gradient(900px 500px at 0% 110%,rgba(34,211,238,.08),transparent 60%),var(--bg);color:var(--text);line-height:1.55;-webkit-font-smoothing:antialiased}a{color:var(--accent2);text-decoration:none}a:hover{text-decoration:underline}button{font-family:inherit;cursor:pointer}::-webkit-scrollbar{width:10px;height:10px}::-webkit-scrollbar-track{background:transparent}::-webkit-scrollbar-thumb{background:var(--border2);border-radius:6px}.app{min-height:100vh;display:flex}.sidebar{width:252px;flex-shrink:0;background:var(--bg2);border-right:1px solid var(--border);display:flex;flex-direction:column;position:sticky;top:0;height:100vh;z-index:20}.sidebar .brand{display:flex;align-items:center;gap:10px;padding:20px 18px;font-weight:800;font-size:20px;letter-spacing:.3px}.sidebar .brand img,.sidebar .brand svg{width:34px;height:34px}.sidebar .brand span b{background:linear-gradient(90deg,var(--accent),var(--accent2));-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent}.sidebar nav{flex:1;overflow-y:auto;padding:8px 10px 16px}.sidebar nav .group-label{font-size:11px;text-transform:uppercase;letter-spacing:1px;color:var(--text3);padding:14px 12px 6px}.nav-item{display:flex;align-items:center;gap:11px;padding:10px 12px;border-radius:10px;color:var(--text2);font-size:14px;margin-bottom:2px;transition:all .15s;cursor:pointer;border:none;background:none;width:100%;text-align:left}.nav-item:hover{background:var(--bg3);color:var(--text)}.nav-item.active{background:linear-gradient(90deg,#6366f140,#22d3ee1f);color:var(--text);font-weight:600}.nav-item .ic{width:20px;text-align:center;font-size:16px}.sidebar .side-foot{padding:14px;border-top:1px solid var(--border);font-size:12px;color:var(--text3)}.main{flex:1;min-width:0;display:flex;flex-direction:column}.topbar{display:flex;align-items:center;gap:16px;padding:14px 26px;background:#0b0f1abf;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:15}.topbar h1{font-size:19px;font-weight:700}.topbar .spacer{flex:1}.user-chip{display:flex;align-items:center;gap:10px}.avatar{width:34px;height:34px;border-radius:50%;background:linear-gradient(135deg,var(--accent),var(--accent2));display:flex;align-items:center;justify-content:center;font-weight:700;color:#fff;font-size:14px}.content{padding:24px 26px 60px;flex:1;max-width:1240px;width:100%;margin:0 auto}.grid{display:grid;gap:16px}.grid-2{grid-template-columns:repeat(auto-fit,minmax(300px,1fr))}.grid-3{grid-template-columns:repeat(auto-fill,minmax(260px,1fr))}.grid-4{grid-template-columns:repeat(auto-fill,minmax(210px,1fr))}.card{background:var(--panel);border:1px solid var(--border);border-radius:var(--radius);padding:18px}.card.hover{transition:all .2s}.card.hover:hover{border-color:var(--accent);transform:translateY(-2px);box-shadow:var(--shadow)}.stat{display:flex;flex-direction:column;gap:6px}.stat .label{font-size:12px;color:var(--text2);text-transform:uppercase;letter-spacing:.6px}.stat .value{font-size:26px;font-weight:800}.stat .sub{font-size:12px;color:var(--text3)}.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:10px 18px;border-radius:10px;border:1px solid transparent;font-size:14px;font-weight:600;transition:all .15s;background:var(--bg3);color:var(--text)}.btn:hover{filter:brightness(1.15)}.btn-primary{background:linear-gradient(90deg,var(--accent),#4f46e5);color:#fff}.btn-accent{background:linear-gradient(90deg,#0891b2,var(--accent2));color:#fff}.btn-green{background:var(--green);color:#04241a}.btn-danger{background:#f8717126;color:var(--red);border-color:#f871714d}.btn-ghost{background:transparent;border-color:var(--border2);color:var(--text2)}.btn-sm{padding:6px 12px;font-size:13px;border-radius:8px}.btn:disabled{opacity:.55;cursor:not-allowed}.input,.select,textarea.input{width:100%;padding:10px 13px;border-radius:10px;border:1px solid var(--border2);background:var(--bg2);color:var(--text);font-size:14px;font-family:inherit;outline:none;transition:border .15s}.input:focus,.select:focus,textarea.input:focus{border-color:var(--accent)}.input::placeholder{color:var(--text3)}label.field{display:flex;flex-direction:column;gap:6px;font-size:13px;color:var(--text2);margin-bottom:14px}.field-row{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:12px}.badge{display:inline-flex;align-items:center;gap:5px;padding:3px 10px;border-radius:999px;font-size:12px;font-weight:600}.badge.green{background:#34d39926;color:var(--green)}.badge.red{background:#f8717126;color:var(--red)}.badge.amber{background:#fbbf2426;color:var(--amber)}.badge.blue{background:#60a5fa26;color:var(--blue)}.badge.purple{background:#a78bfa26;color:var(--purple)}.badge.gray{background:var(--bg3);color:var(--text2)}.chip{display:inline-block;padding:3px 9px;border-radius:7px;background:var(--bg3);border:1px solid var(--border);font-size:12px;color:var(--text2)}.muted{color:var(--text2)}.small{font-size:13px}.tiny{font-size:12px;color:var(--text3)}.row{display:flex;align-items:center;gap:10px;flex-wrap:wrap}.spread{display:flex;align-items:center;justify-content:space-between;gap:10px;flex-wrap:wrap}.col{display:flex;flex-direction:column;gap:10px}.mt{margin-top:18px}.mb{margin-bottom:14px}.muted-bg{background:var(--bg2)}.progress{height:8px;background:var(--bg3);border-radius:999px;overflow:hidden}.progress>div{height:100%;background:linear-gradient(90deg,var(--accent),var(--accent2));border-radius:999px;transition:width .4s}.progress.green>div{background:var(--green)}.progress.red>div{background:var(--red)}.progress.amber>div{background:var(--amber)}.divider{border:none;border-top:1px solid var(--border);margin:14px 0}table.tbl{width:100%;border-collapse:collapse;font-size:13.5px}table.tbl th{text-align:left;padding:10px 12px;color:var(--text3);font-size:12px;text-transform:uppercase;letter-spacing:.6px;border-bottom:1px solid var(--border)}table.tbl td{padding:11px 12px;border-bottom:1px solid var(--border)}table.tbl tr:hover td{background:#6366f10d}.auth-wrap{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:20px}.auth-card{width:100%;max-width:430px;background:var(--panel);border:1px solid var(--border);border-radius:18px;padding:34px;box-shadow:var(--shadow)}.auth-card h1{font-size:26px;margin-bottom:4px}.auth-tabs{display:flex;gap:8px;margin-bottom:20px}.auth-tabs button{flex:1;padding:9px;border-radius:9px;border:1px solid var(--border2);background:transparent;color:var(--text2);font-weight:600}.auth-tabs button.on{background:linear-gradient(90deg,var(--accent),#4f46e5);color:#fff;border-color:transparent}.qcard{background:var(--panel);border:1px solid var(--border);border-radius:var(--radius);padding:20px}.qcard .qtext{font-size:15.5px;line-height:1.7;white-space:pre-wrap}.option{display:flex;align-items:flex-start;gap:12px;padding:12px 14px;margin-top:10px;border:1px solid var(--border2);border-radius:10px;cursor:pointer;transition:all .12s;font-size:14.5px;background:var(--bg2)}.option:hover{border-color:var(--accent)}.option .key{width:26px;height:26px;border-radius:8px;background:var(--bg3);display:flex;align-items:center;justify-content:center;font-weight:700;font-size:13px;flex-shrink:0}.option.selected{border-color:var(--accent);background:#6366f124}.option.correct{border-color:var(--green);background:#34d3991f}.option.wrong{border-color:var(--red);background:#f871711f}.timer-panel{background:var(--panel);border:1px solid var(--border);border-radius:var(--radius);padding:14px 16px}.timer{font-size:28px;font-weight:800;font-variant-numeric:tabular-nums}.timer.warn{color:var(--red);animation:pulse 1s infinite}@keyframes pulse{0%,to{opacity:1}50%{opacity:.55}}.metric{background:var(--bg2);border:1px solid var(--border);border-radius:10px;padding:10px 12px}.metric .m-label{font-size:11px;color:var(--text3);text-transform:uppercase;letter-spacing:.5px}.metric .m-value{font-size:17px;font-weight:700;margin-top:2px}.palette{display:grid;grid-template-columns:repeat(auto-fill,minmax(38px,1fr));gap:6px}.palette .qdot{height:38px;border-radius:9px;border:1px solid var(--border2);background:var(--bg2);color:var(--text2);font-size:13px;font-weight:600;display:flex;align-items:center;justify-content:center;cursor:pointer}.palette .qdot.current{border-color:var(--accent);box-shadow:0 0 0 2px #6366f159}.palette .qdot.answered{background:#34d3992e;border-color:var(--green);color:var(--green)}.palette .qdot.wrong{background:#f8717138;border-color:var(--red);color:var(--red)}.palette .qdot.review{background:#fbbf2433;border-color:var(--amber);color:var(--amber)}.modal-overlay{position:fixed;top:0;right:0;bottom:0;left:0;background:#05080fb8;-webkit-backdrop-filter:blur(4px);backdrop-filter:blur(4px);display:flex;align-items:center;justify-content:center;z-index:100;padding:20px}.modal{background:var(--panel);border:1px solid var(--border2);border-radius:16px;width:100%;max-width:620px;max-height:88vh;overflow-y:auto;padding:24px;box-shadow:var(--shadow)}.solution{background:linear-gradient(135deg,#6366f11f,#22d3ee14);border:1px solid rgba(99,102,241,.35);border-radius:var(--radius);padding:18px}.ai-bubble{background:var(--bg2);border:1px solid var(--border);border-radius:14px;padding:14px;white-space:pre-wrap;font-size:14px}.ai-bubble:before{content:"✦ AI Tutor";display:block;font-size:11px;color:var(--accent2);font-weight:700;letter-spacing:1px;margin-bottom:8px}.hero{text-align:center;padding:40px 0 28px}.hero h1{font-size:clamp(28px,5vw,46px);font-weight:800;line-height:1.15}.hero h1 span{background:linear-gradient(90deg,var(--accent),var(--accent2));-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent}.hero p{color:var(--text2);max-width:640px;margin:14px auto 22px;font-size:16px}.pill{display:inline-flex;gap:6px;flex-wrap:wrap;justify-content:center}.empty{text-align:center;padding:50px 20px;color:var(--text3)}.spin{display:inline-block;width:18px;height:18px;border:2px solid var(--border2);border-top-color:var(--accent);border-radius:50%;animation:rot .8s linear infinite}@keyframes rot{to{transform:rotate(360deg)}}.toast-wrap{position:fixed;bottom:22px;right:22px;display:flex;flex-direction:column;gap:10px;z-index:200}.toast{background:var(--panel2);border:1px solid var(--border2);border-left:4px solid var(--accent);border-radius:10px;padding:13px 18px;box-shadow:var(--shadow);font-size:14px;max-width:360px;animation:slidein .25s}.toast.ok{border-left-color:var(--green)}.toast.err{border-left-color:var(--red)}@keyframes slidein{0%{transform:translate(30px);opacity:0}to{transform:none;opacity:1}}.skeleton{background:linear-gradient(90deg,var(--bg3),var(--panel2),var(--bg3));background-size:200% 100%;animation:shimmer 1.4s infinite;border-radius:10px}@keyframes shimmer{to{background-position:-200% 0}}@media (max-width: 860px){.sidebar{position:fixed;left:-260px;transition:left .25s;box-shadow:var(--shadow)}.sidebar.open{left:0}.main{margin-left:0}.content{padding:16px}.topbar{padding:12px 16px}.burger{display:flex!important}}.burger{display:none;background:none;border:none;color:var(--text);font-size:22px}.mobile-backdrop{position:fixed;top:0;right:0;bottom:0;left:0;background:#00000080;z-index:19}
