:root{
  --bg:#0b1020;
  --panel:#111833;
  --panel2:#0f1630;
  --text:#e9ecff;
  --muted:#aab2e3;
  --accent:#7aa2ff;
  --danger:#ff6b6b;
  --ok:#37d67a;
  --border:rgba(255,255,255,.12);
  --shadow: 0 10px 30px rgba(0,0,0,.35);
  --radius:14px;
  --mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
  --sans: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Noto Sans, Arial, "Apple Color Emoji", "Segoe UI Emoji";
}

*{box-sizing:border-box}
html,body{min-height:100%}
body{
  margin:0;
  font-family:var(--sans);
  background:
    radial-gradient(900px 450px at 20% 10%, rgba(122,162,255,.25), transparent 55%),
    radial-gradient(800px 400px at 90% 40%, rgba(55,214,122,.18), transparent 55%),
    radial-gradient(600px 300px at 40% 90%, rgba(255,107,107,.16), transparent 55%),
    var(--bg);
  background-attachment: fixed;
  color:var(--text);
}

a{color:inherit}
.wrap{max-width:1100px;margin:0 auto;padding:22px}
.topbar{
  display:flex;align-items:center;justify-content:space-between;gap:12px;
  padding:14px 16px;border:1px solid var(--border);border-radius:var(--radius);
  background:rgba(17,24,51,.8);backdrop-filter: blur(10px);
  box-shadow: var(--shadow);
}
.brand{display:flex;align-items:center;gap:10px}
.logo{
  width:34px;height:34px;border-radius:10px;
  object-fit:contain;
  background: rgba(15,22,48,.5);
  flex-shrink:0;
}
.brand h1{font-size:15px;margin:0;letter-spacing:.2px}
.pill{
  display:inline-flex;align-items:center;gap:8px;
  padding:7px 10px;border:1px solid var(--border);border-radius:999px;
  background:rgba(15,22,48,.9);
  color:var(--muted);
  font-size:12px;
}
.pill-info{font-size:15px;padding:9px 12px;color:var(--text)}
.pill-info .mono{font-size:15px}
.pill-auth{white-space:nowrap;flex-shrink:0;max-width:100%;overflow:hidden;text-overflow:ellipsis}
.mono{font-family:var(--mono)}
.actions{display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.btn{
  border:1px solid var(--border);
  background:rgba(15,22,48,.95);
  color:var(--text);
  padding:9px 12px;border-radius:12px;
  cursor:pointer;
  transition: transform .05s ease, background .2s ease, border-color .2s ease;
}
.btn:hover{background:rgba(17,24,51,.95);border-color: rgba(255,255,255,.18)}
.btn:active{transform: translateY(1px)}
.btn.primary{border-color: rgba(122,162,255,.5);background: rgba(122,162,255,.16)}
.btn.danger{border-color: rgba(255,107,107,.6);background: rgba(255,107,107,.12)}
.btn.ok{border-color: rgba(55,214,122,.6);background: rgba(55,214,122,.12)}
.btn.small{padding:7px 10px;border-radius:10px;font-size:12px}

.grid{display:grid;grid-template-columns: 1.4fr 1fr;gap:16px;margin-top:16px}
@media (max-width: 980px){.grid{grid-template-columns: 1fr}}

.card{
  border:1px solid var(--border);
  background: rgba(17,24,51,.72);
  border-radius: var(--radius);
  padding:16px;
  box-shadow: var(--shadow);
}
.card h2{margin:0 0 10px;font-size:14px;color:var(--muted);font-weight:600}
.card .hint{margin:8px 0 0;color:var(--muted);font-size:12px;line-height:1.45}

.list{display:flex;flex-direction:column;gap:10px}
.row{
  display:flex;justify-content:space-between;align-items:flex-start;gap:12px;
  padding:12px;border:1px solid var(--border);border-radius:12px;background: rgba(15,22,48,.75);
}
.row .title{font-weight:650}
.row .meta{color:var(--muted);font-size:12px;margin-top:4px;line-height:1.4}
.row .right{display:flex;align-items:center;gap:8px;flex-wrap:wrap;justify-content:flex-end}

.badge{
  font-size:12px;
  padding:4px 8px;border-radius:999px;border:1px solid var(--border);
  color:var(--muted);
  background: rgba(255,255,255,.04);
}
.badge.ok{border-color: rgba(55,214,122,.55);color: rgba(55,214,122,.95);background: rgba(55,214,122,.08)}
.badge.warn{border-color: rgba(255,200,87,.55);color: rgba(255,200,87,.95);background: rgba(255,200,87,.08)}
.badge.danger{border-color: rgba(255,107,107,.55);color: rgba(255,107,107,.95);background: rgba(255,107,107,.08)}

.field{display:flex;flex-direction:column;gap:6px;margin-top:10px}
.field label{font-size:12px;color:var(--muted)}
.field input, .field select{
  width:100%;
  padding:10px 12px;
  border-radius:12px;
  border:1px solid var(--border);
  background: rgba(15,22,48,.85);
  color: var(--text);
  outline:none;
}
.field input:focus, .field select:focus{border-color: rgba(122,162,255,.55)}

.split{display:grid;grid-template-columns: 1fr 1fr;gap:10px}
@media (max-width: 520px){.split{grid-template-columns:1fr}}

.notice{
  margin-top:12px;
  padding:12px;
  border-radius:12px;
  border:1px solid var(--border);
  background: rgba(15,22,48,.7);
  color: var(--muted);
  font-size: 12px;
  line-height:1.45;
}
.notice strong{color: var(--text)}

.skeleton{opacity:.85}
.empty{color:var(--muted);font-size:13px;padding:10px 0}

.section-divider{
  border:0;
  height:1px;
  background:var(--border);
  margin:16px 0;
}

.challenge-btn{
  border-color:rgba(255,200,87,.55);
  background:linear-gradient(135deg,rgba(255,200,87,.18),rgba(255,107,107,.14));
  color:#ffe066;
  font-weight:700;
  letter-spacing:.3px;
}
.challenge-btn:hover{background:linear-gradient(135deg,rgba(255,200,87,.28),rgba(255,107,107,.22))}
.challenge-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:8px}
.challenge-timer{font-size:22px;font-weight:bold;color:#ff6b6b;font-family:var(--mono)}
.challenge-nav-row{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-bottom:10px;flex-wrap:wrap}
.challenge-nav-row .challenge-progress{text-align:center;color:var(--muted);font-size:13px;margin:0;flex:1;min-width:60px}
.challenge-progress{text-align:center;color:var(--muted);font-size:13px;margin-bottom:10px}
.challenge-problem-wrapper{position:relative;display:inline-block;width:100%;padding-bottom:300px;background:#fff}
.challenge-problem-img{width:100%;max-width:100%;height:auto;display:block;background:#fff}
#challengeDrawCanvas{position:absolute;top:0;left:0;pointer-events:none;touch-action:none}
.challenge-float-btn{position:fixed;right:14px;width:48px;height:48px;border-radius:14px;background:transparent;border:1px solid transparent;display:flex;align-items:center;justify-content:center;cursor:pointer;z-index:10000;transition:all .2s;outline:none}
.challenge-float-btn:hover{background:transparent;box-shadow:none;opacity:.9}
.challenge-float-btn.active{background:transparent;border-color:transparent}
.challenge-float-btn .challenge-float-icon{font-size:20px;opacity:.65}
.challenge-float-btn.active .challenge-float-icon{opacity:1}
.challenge-float-btn-clear{bottom:120px}
#challengeToggleDraw{bottom:184px}
body.challenge-draw-noscroll{overflow:hidden !important;touch-action:none !important}
.challenge-input{
  width:100%;
  padding:10px 12px;
  border-radius:12px;
  border:1px solid var(--border);
  background:rgba(15,22,48,.85);
  color:var(--text);
  outline:none;
  margin-top:6px;
  font-size:14px;
}
.challenge-input:focus{border-color:rgba(122,162,255,.55)}
.challenge-input::placeholder{color:var(--muted);opacity:.6}
.challenge-detail{margin-top:8px;padding:8px;background:rgba(15,22,48,.5);border-radius:8px}
#challengeProblemImg,
.challenge-img-preview img{
  background:#fff;
  padding:10px;
}