:root {
  --bg: #0a0e17;
  --bg-alt: #10182a;
  --card: #131c30;
  --border: #1f2b45;
  --primary: #5b8cff;
  --primary-glow: #5b8cffaa;
  --accent: #00e5c7;
  --warn: #ffb454;
  --danger: #ff5c72;
  --success: #3ddc84;
  --text: #e7ecf7;
  --text-dim: #8b96ad;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: 'Segoe UI', system-ui, Arial, sans-serif;
  background:
    radial-gradient(circle at 20% 0%, #16224a55 0%, transparent 45%),
    radial-gradient(circle at 85% 15%, #0f3d3855 0%, transparent 40%),
    var(--bg);
  color: var(--text);
  min-height: 100vh;
}

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

.container { max-width: 1080px; margin: 0 auto; padding: 0 20px; }

/* ---------------- NAVBAR ---------------- */
nav.topbar {
  background: rgba(16, 24, 42, 0.9);
  border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 50;
  backdrop-filter: blur(6px);
}
nav.topbar .inner {
  max-width: 1080px; margin: 0 auto; padding: 12px 20px;
  display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 10px;
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 1.15em; color: var(--text); }
.brand small { display:block; font-weight: 400; font-size: 0.6em; color: var(--text-dim); }
.navlinks { display: flex; gap: 18px; align-items: center; flex-wrap: wrap; }
.navlinks a { color: var(--text-dim); font-weight: 500; font-size: 0.95em; }
.navlinks a:hover { color: var(--accent); text-decoration:none; }
.navlinks a.active { color: var(--primary); }
.btn {
  display: inline-block; padding: 8px 18px; border-radius: 8px; border: none;
  background: linear-gradient(135deg, var(--primary), #7c5cff);
  color: white; font-weight: 600; cursor: pointer; font-size: 0.95em;
}
.btn:hover { filter: brightness(1.1); text-decoration:none; }
.btn.secondary { background: transparent; border: 1px solid var(--border); color: var(--text); }
.btn.danger { background: linear-gradient(135deg, #ff5c72, #ff8a5c); }
.btn.small { padding: 5px 12px; font-size: 0.85em; }

/* ---------------- HERO ---------------- */
.hero {
  padding: 70px 20px 60px;
  text-align: center;
  border-bottom: 1px solid var(--border);
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(91,140,255,0.06) 1px, transparent 1px),
    linear-gradient(90deg, rgba(91,140,255,0.06) 1px, transparent 1px);
  background-size: 34px 34px;
  mask-image: radial-gradient(ellipse at center, black 30%, transparent 75%);
}
.hero .inner { position: relative; z-index: 2; }
.hero h1 {
  font-size: 2.6em; margin: 16px 0 6px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero .tagline { color: var(--text-dim); font-size: 1.1em; max-width: 620px; margin: 0 auto 10px; }
.hero .host { color: var(--warn); font-size: 0.95em; margin-bottom: 26px; }
.hero .cta { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; margin-top: 20px; }
.status-pill {
  display: inline-block; padding: 6px 16px; border-radius: 999px; font-size: 0.85em; font-weight: 600;
  margin-bottom: 18px;
}
.status-pill.running { background: #16382b; color: var(--success); border: 1px solid #1f5c3f; }
.status-pill.not_started { background: #3a3115; color: var(--warn); border: 1px solid #5c4a1f; }
.status-pill.ended { background: #3a1c22; color: var(--danger); border: 1px solid #5c2530; }

/* ---------------- CARDS / SECTIONS ---------------- */
main { padding: 40px 0 80px; }
.section-title { color: var(--accent); font-size: 1.3em; margin: 34px 0 14px; border-bottom: 1px solid var(--border); padding-bottom: 8px; }
.card {
  background: var(--card); border: 1px solid var(--border); border-radius: 12px;
  padding: 22px 24px; margin-bottom: 16px;
}
.grid { display: grid; gap: 16px; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); }
.chal-card {
  background: var(--card); border: 1px solid var(--border); border-radius: 12px;
  padding: 18px 20px; transition: border-color .15s;
}
.chal-card:hover { border-color: var(--primary); }
.chal-card.solved { border-color: var(--success); }
.chal-card h3 { margin: 4px 0; font-size: 1.05em; }
.chal-card .pts { color: var(--warn); font-weight: 700; float: right; }
.chal-card .cat-tag {
  font-size: 0.72em; text-transform: uppercase; letter-spacing: 0.05em;
  color: var(--text-dim); background: var(--bg-alt); padding: 3px 8px; border-radius: 4px;
}
.solved-badge { color: var(--success); font-weight: 700; font-size: 0.85em; }

/* ---------------- FORMS ---------------- */
form.stacked { display: flex; flex-direction: column; gap: 14px; max-width: 420px; }
form.stacked.wide { max-width: 640px; }
label { font-size: 0.9em; color: var(--text-dim); margin-bottom: 4px; display: block; }
input[type=text], input[type=email], input[type=password], input[type=number],
input[type=datetime-local], textarea, select {
  width: 100%; padding: 10px 12px; border-radius: 8px; border: 1px solid var(--border);
  background: var(--bg-alt); color: var(--text); font-size: 0.95em;
}
textarea { min-height: 90px; font-family: inherit; }
input:focus, textarea:focus, select:focus { outline: none; border-color: var(--primary); }
.checkbox-row { display: flex; align-items: center; gap: 8px; }
.checkbox-row input { width: auto; }

/* ---------------- FLASH MESSAGES ---------------- */
.flash { padding: 12px 16px; border-radius: 8px; margin-bottom: 14px; font-size: 0.92em; }
.flash.success { background: #14301f; color: var(--success); border: 1px solid #1f5c3f; }
.flash.error { background: #341419; color: var(--danger); border: 1px solid #5c2530; }

/* ---------------- TABLES ---------------- */
table { width: 100%; border-collapse: collapse; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--border); font-size: 0.92em; }
th { color: var(--text-dim); text-transform: uppercase; font-size: 0.75em; letter-spacing: 0.04em; }
tr.me { background: rgba(91,140,255,0.08); }
.rank-1 { color: #ffd479; font-weight: 800; }
.rank-2 { color: #d9d9d9; font-weight: 700; }
.rank-3 { color: #d99356; font-weight: 700; }

/* ---------------- MISC ---------------- */
code, pre { background: var(--bg-alt); color: var(--accent); padding: 2px 6px; border-radius: 4px; font-size: 0.9em; }
pre { padding: 14px; overflow-x: auto; }
.dim { color: var(--text-dim); }
.footer {
  text-align: center; color: var(--text-dim); padding: 30px 20px; border-top: 1px solid var(--border);
  font-size: 0.85em;
}
.footer .powered { color: var(--primary); font-weight: 600; }
.stat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 14px; }
.stat-box { background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 18px; text-align: center; }
.stat-box .num { font-size: 1.8em; font-weight: 800; color: var(--accent); }
.stat-box .label { color: var(--text-dim); font-size: 0.85em; margin-top: 4px; }
.badge { display:inline-block; padding: 2px 8px; border-radius: 999px; font-size: 0.75em; font-weight:600;}
.badge.admin { background:#3a2e15; color:var(--warn); }
.badge.banned { background:#3a1c22; color:var(--danger); }
.frozen-banner {
  background: #16223a; border: 1px solid var(--primary); color: var(--accent);
  padding: 10px 16px; border-radius: 8px; margin-bottom: 18px; text-align:center; font-size: 0.9em;
}
.admin-tabs { display:flex; gap:8px; flex-wrap:wrap; margin-bottom: 24px; }
.admin-tabs a {
  padding: 8px 14px; border-radius: 8px; background: var(--card); border: 1px solid var(--border);
  color: var(--text-dim); font-size: 0.9em;
}
.admin-tabs a.active { color: var(--accent); border-color: var(--accent); }