:root{--bg:#0b1026;--card:#141b3d;--card2:#1b2450;--line:#26306a;--tx:#e8ecff;--mut:#9aa6d8;
--cy:#00d4f0;--pk:#ff3d9a;--vi:#7c4dff;--am:#ffb300;--ok:#2ecc71;--bad:#ff5c6c;--warn:#ffb300}
*{box-sizing:border-box}
html,body{margin:0;background:var(--bg);color:var(--tx);font:15px/1.5 system-ui,-apple-system,"Segoe UI",Roboto,sans-serif}
a{color:var(--cy);text-decoration:none}
.wrap{max-width:1100px;margin:0 auto;padding:12px 14px 70px}
header.top{position:sticky;top:0;z-index:10;background:rgba(11,16,38,.92);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
header.top .in{max-width:1100px;margin:0 auto;display:flex;align-items:center;gap:12px;padding:10px 14px}
.brand{font-weight:800;font-size:18px;letter-spacing:.5px;color:#fff;white-space:nowrap}
.brand b{background:linear-gradient(90deg,var(--cy),var(--vi),var(--pk));-webkit-background-clip:text;background-clip:text;color:transparent}
nav{display:flex;gap:4px;margin-left:auto;flex-wrap:wrap}
nav a{color:var(--mut);padding:6px 10px;border-radius:8px;font-size:14px}
nav a.on,nav a:hover{color:#fff;background:var(--card2)}
.card{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:14px;margin:12px 0}
h1{font-size:22px;margin:8px 0 4px}h2{font-size:17px;margin:4px 0 10px}h3{font-size:15px;margin:12px 0 6px;color:var(--mut)}
.mut{color:var(--mut)}.sm{font-size:13px}
.grid{display:grid;gap:10px}.g2{grid-template-columns:repeat(2,1fr)}.g3{grid-template-columns:repeat(3,1fr)}.g4{grid-template-columns:repeat(4,1fr)}
@media(max-width:700px){.g4{grid-template-columns:repeat(2,1fr)}.g3{grid-template-columns:repeat(3,1fr)}}
.kpi{background:var(--card2);border-radius:12px;padding:10px;text-align:center}
.kpi .v{font-size:26px;font-weight:800}.kpi .l{font-size:12px;color:var(--mut)}
.fire{color:var(--am)}
.btn{display:inline-block;border:0;border-radius:10px;padding:9px 16px;font-weight:700;font-size:14px;cursor:pointer;color:#fff;background:var(--card2);border:1px solid var(--line)}
.btn.pri{background:linear-gradient(90deg,var(--vi),var(--pk));border:0}
.btn.cy{background:var(--cy);color:#04121a;border:0}
.btn.sm{padding:5px 10px;font-size:12px}
.btn:disabled{opacity:.5}
input,select,textarea{width:100%;background:#0e1533;color:var(--tx);border:1px solid var(--line);border-radius:10px;padding:10px;font:inherit}
textarea{font-family:ui-monospace,Consolas,monospace;font-size:13px}
label{display:block;font-size:13px;color:var(--mut);margin:10px 0 4px}
.flash{padding:10px 14px;border-radius:10px;margin:10px 0;font-weight:600}
.flash.ok{background:#12391f;color:#7cf0a5}.flash.err{background:#3d1220;color:#ff9aa8}
table{width:100%;border-collapse:collapse;font-size:14px}
th,td{padding:8px 6px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}
th{color:var(--mut);font-weight:600;font-size:12px;text-transform:uppercase}
.tbl{overflow-x:auto}
.tag{display:inline-block;font-size:11px;padding:2px 8px;border-radius:20px;background:var(--card2);color:var(--mut);white-space:nowrap}
.tag.Easy{color:#7cf0a5}.tag.Medium{color:var(--am)}.tag.Hard{color:var(--bad)}
.v-AC{color:var(--ok);font-weight:700}.v-WA,.v-RE,.v-CE,.v-IE{color:var(--bad);font-weight:700}.v-TLE{color:var(--warn);font-weight:700}
.prow{display:flex;align-items:center;gap:10px;padding:10px;border-radius:10px;color:var(--tx);border:1px solid transparent}
a.prow:hover{background:var(--card2);border-color:var(--line)}
.dot{width:22px;height:22px;border-radius:50%;display:grid;place-items:center;font-size:12px;flex:none;border:2px solid var(--line)}
.dot.done{background:var(--ok);border-color:var(--ok);color:#04121a;font-weight:900}
.dot.try{border-color:var(--warn)}
.prow .t{flex:1}
.potd{background:linear-gradient(135deg,#2a1b5e,#4a1640);border:1px solid #5a3a9a}
.week{display:flex;gap:6px;justify-content:center;margin-top:8px}
.week span{width:30px;height:30px;border-radius:8px;background:var(--card2);display:grid;place-items:center;font-size:11px;color:var(--mut)}
.week span.on{background:var(--am);color:#1a1200;font-weight:800}
.week span.td{outline:2px solid var(--cy)}
.bar{height:8px;background:var(--card2);border-radius:10px;overflow:hidden}.bar i{display:block;height:100%;background:linear-gradient(90deg,var(--cy),var(--pk))}
.battle{display:grid;grid-template-columns:1fr auto 1fr;gap:8px;align-items:center;text-align:center}
.battle .vs{font-weight:900;color:var(--am)}
.sec1{color:var(--cy)}.sec2{color:var(--pk)}
/* problem page */
.pp{display:grid;grid-template-columns:1fr 1fr;gap:14px}
@media(max-width:900px){.pp{grid-template-columns:1fr}}
.stmt{white-space:pre-wrap}
pre.io{background:#0e1533;border:1px solid var(--line);border-radius:10px;padding:10px;margin:4px 0 10px;white-space:pre-wrap;font-size:13px;overflow-x:auto}
.CodeMirror{height:340px;border-radius:10px;border:1px solid var(--line);font-size:14px}
.keys{display:flex;flex-wrap:wrap;gap:5px;margin:8px 0}
.keys button{flex:1 0 34px;min-width:34px;padding:8px 0;border-radius:8px;border:1px solid var(--line);background:var(--card2);color:#fff;font:600 15px ui-monospace,monospace}
.res{margin-top:10px}
.tc{display:inline-flex;align-items:center;justify-content:center;width:34px;height:34px;margin:3px;border-radius:8px;font-size:12px;font-weight:800}
.tc.AC{background:#12391f;color:#7cf0a5}.tc.WA,.tc.RE{background:#3d1220;color:#ff9aa8}.tc.TLE{background:#3d2e0a;color:var(--am)}
.banner{padding:12px;border-radius:12px;font-weight:800;font-size:17px;text-align:center}
.banner.AC{background:#12391f;color:#7cf0a5}.banner.bad{background:#3d1220;color:#ff9aa8}.banner.TLE{background:#3d2e0a;color:var(--am)}
.spin{display:inline-block;width:16px;height:16px;border:3px solid #fff4;border-top-color:#fff;border-radius:50%;animation:s 1s linear infinite;vertical-align:-3px}
@keyframes s{to{transform:rotate(360deg)}}
.login{max-width:380px;margin:8vh auto}
.logo{font-size:64px;font-weight:900;text-align:center;background:linear-gradient(90deg,var(--cy),var(--vi),var(--pk));-webkit-background-clip:text;background-clip:text;color:transparent;font-family:ui-monospace,monospace}
.me{background:var(--card2)}
.rk{font-weight:800;width:40px}
.r1{color:#ffd54f}.r2{color:#cfd8dc}.r3{color:#ffab91}
.row{display:flex;gap:8px;align-items:center;flex-wrap:wrap}
.right{margin-left:auto}
.testrow{border:1px solid var(--line);border-radius:10px;padding:10px;margin:8px 0}
.testrow .g2 textarea{min-height:80px}
@media(max-width:520px){header.top .in{gap:6px;padding:8px 10px}.brand .bt{display:none}nav{gap:0}nav a{padding:6px 7px;font-size:13px}}
.steps{display:flex;gap:6px;margin-top:10px}.steps span{flex:1;text-align:center;padding:6px;border-radius:8px;background:var(--card2);color:var(--mut);font-size:12px;font-weight:700}
.steps span.on{background:linear-gradient(90deg,var(--vi),var(--pk));color:#fff}
.learn{border-color:#2f5a9a;background:#101d42}
.mcq{border:1px solid var(--line);border-radius:12px;padding:12px;margin:10px 0}
.mcq.bad{border-color:var(--bad);background:#2a0f1a}
.qtext{margin-bottom:6px;white-space:pre-wrap}
.opt{display:flex;gap:10px;align-items:flex-start;padding:9px 10px;margin:4px 0;border-radius:10px;background:#0e1533;color:var(--tx);font-size:14px;cursor:pointer}
.opt input{width:auto;margin-top:3px}
.opt span{font-family:ui-monospace,Consolas,monospace;font-size:13px;white-space:pre-wrap}
.badges{display:flex;flex-wrap:wrap;gap:6px}
.badge{display:inline-flex;align-items:center;gap:6px;padding:6px 10px;border-radius:20px;background:var(--card2);font-size:12px;font-weight:700}
.badge.off{opacity:.35;filter:grayscale(1)}
.hof li{margin:4px 0}.hof ol{margin:4px 0;padding-left:22px}
details summary{cursor:pointer}
.lock{opacity:.6}
@media(max-width:700px){.hof .g3{grid-template-columns:1fr}.hof h3 br{display:none}}
.steps span.ok{background:#12391f;color:#7cf0a5}
.today{background:linear-gradient(135deg,#132a5e,#1b2450);border-color:#2f5a9a}
.foot{margin:30px 0 0;padding:16px 0 4px;border-top:1px solid var(--line);text-align:center;color:var(--mut);font-size:12px;line-height:1.7}
.foot b{color:var(--tx)}
.danger{border-color:#6b2333}