:root {
  --bg: #0b0f19;
  --panel: #121826;
  --panel2: rgba(18, 24, 38, 0.72);
  --text: #e5e7eb;
  --muted: #9aa5b1;
  --primary: #2dd4bf;
  --primary2: #60a5fa;
  --danger: #ef4444;
  --success: #22c55e;
  --border: #1f2937;
  --radius: 16px;
  --shadow: 0 24px 80px rgba(0, 0, 0, 0.55);
}
* { box-sizing: border-box }
body {
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, Noto Sans, sans-serif;
  background:
    radial-gradient(900px 480px at 12% 10%, rgba(96, 165, 250, 0.18), transparent 60%),
    radial-gradient(820px 520px at 86% 22%, rgba(45, 212, 191, 0.14), transparent 62%),
    radial-gradient(720px 520px at 50% 110%, rgba(168, 85, 247, 0.12), transparent 55%),
    linear-gradient(180deg, #070a12 0%, #0b0f19 45%, #0f172a 100%);
  color: var(--text);
  min-height: 100vh;
}
.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 18px;
  border-bottom: 1px solid var(--border);
  background: rgba(9, 12, 20, 0.5);
  position: sticky;
  top: 0;
  backdrop-filter: blur(8px);
}
.brand {
  font-weight: 900;
  letter-spacing: 0.6px;
  font-size: 14px;
  padding: 10px 12px;
  border-radius: 999px;
  border: 1px solid rgba(255,255,255,0.08);
  background: radial-gradient(circle at 20% 20%, rgba(45,212,191,0.18), transparent 60%), rgba(255,255,255,0.03);
  color: var(--text);
  text-decoration: none;
}
.brand:hover { border-color: rgba(255,255,255,0.14); background: radial-gradient(circle at 20% 20%, rgba(45,212,191,0.22), transparent 60%), rgba(255,255,255,0.05) }
.nav {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: flex-end;
}
.nav a {
  color: var(--text);
  text-decoration: none;
  padding: 10px 12px;
  border-radius: 999px;
  border: 1px solid rgba(255,255,255,0.06);
  background: rgba(255,255,255,0.03);
  transition: transform 120ms ease-out, background 120ms ease-out, border-color 120ms ease-out;
  font-size: 13px;
}
.nav a:hover {
  background: rgba(255,255,255,0.06);
  border-color: rgba(255,255,255,0.12);
  transform: translateY(-1px);
}
.container {
  max-width: 1100px;
  margin: 28px auto;
  padding: 0 16px;
}
.muted { color: var(--muted) }
.grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px }
.grid-2 { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px }
@media (max-width: 820px) { .grid, .grid-2 { grid-template-columns: 1fr } }
.card-head { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 8px }
.hero {
  border-radius: var(--radius);
  border: 1px solid rgba(255,255,255,0.10);
  background:
    radial-gradient(circle at 18% 28%, rgba(96,165,250,0.18), transparent 58%),
    radial-gradient(circle at 74% 22%, rgba(45,212,191,0.16), transparent 54%),
    linear-gradient(180deg, rgba(18,24,38,0.72), rgba(15,23,42,0.82));
  box-shadow: var(--shadow);
  padding: 26px 22px;
  overflow: hidden;
  position: relative;
}
.hero::after {
  content: "";
  position: absolute;
  inset: -120px;
  background:
    radial-gradient(circle at 20% 30%, rgba(45,212,191,0.18), transparent 60%),
    radial-gradient(circle at 70% 70%, rgba(96,165,250,0.16), transparent 60%);
  animation: floatGlow 3.2s ease-in-out infinite;
  pointer-events: none;
}
.hero > * { position: relative; z-index: 1 }
.hero-title {
  font-size: 34px;
  letter-spacing: -0.6px;
  margin: 0 0 8px;
  font-weight: 950;
}
.hero-subtitle { margin: 0 0 18px; color: var(--muted); line-height: 1.6 }
.cta { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 14px }
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 14px;
  border-radius: 12px;
  border: 1px solid rgba(45,212,191,0.35);
  background: linear-gradient(90deg, rgba(45,212,191,0.9), rgba(96,165,250,0.9));
  color: #071015;
  font-weight: 900;
  text-decoration: none;
}
.btn-primary:hover { filter: brightness(1.05) }
.btn-ghost {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 14px;
  border-radius: 12px;
  border: 1px solid rgba(255,255,255,0.10);
  background: rgba(255,255,255,0.04);
  color: var(--text);
  font-weight: 800;
  text-decoration: none;
}
.btn-ghost:hover { background: rgba(255,255,255,0.07) }
.stat-row { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 14px }
.stat {
  padding: 10px 12px;
  border-radius: 14px;
  border: 1px solid rgba(255,255,255,0.08);
  background: rgba(255,255,255,0.03);
  min-width: 160px;
}
.stat .k { font-size: 12px; color: var(--muted) }
.stat .v { font-size: 18px; font-weight: 900; margin-top: 2px }
.badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 34px;
  padding: 4px 10px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: rgba(45, 212, 191, 0.12);
  color: var(--text);
  font-weight: 700;
}
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.55);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  z-index: 9999;
  animation: fadeIn 180ms ease-out;
}
.modal-backdrop.hide { opacity: 0; transition: opacity 180ms ease-out }
.modal {
  width: min(520px, 100%);
  background: linear-gradient(180deg, rgba(18, 24, 38, 0.98), rgba(15, 23, 42, 0.98));
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 18px 14px;
  box-shadow: var(--shadow);
  transform: translateY(6px) scale(0.98);
  animation: popIn 220ms cubic-bezier(0.2, 1.0, 0.2, 1.0) forwards;
}
.modal-title {
  font-size: 18px;
  font-weight: 800;
  margin-bottom: 8px;
}
.modal-body { color: var(--muted); line-height: 1.6 }
.modal-actions { display: flex; justify-content: flex-end; margin-top: 14px }
@keyframes fadeIn { from { opacity: 0 } to { opacity: 1 } }
@keyframes popIn { to { transform: translateY(0) scale(1) } }

.class-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: 12px 0 14px;
}
@media (max-width: 820px) { .class-grid { grid-template-columns: 1fr } }
.class-card {
  display: grid;
  grid-template-columns: 64px 1fr;
  gap: 12px;
  align-items: center;
  padding: 12px;
  border-radius: 14px;
  border: 1px solid var(--border);
  background: rgba(255,255,255,0.04);
  cursor: pointer;
  position: relative;
  overflow: hidden;
}
.class-card input { position: absolute; opacity: 0; pointer-events: none }
.class-card:has(input:checked) {
  border-color: rgba(45, 212, 191, 0.75);
  box-shadow: 0 0 0 3px rgba(45, 212, 191, 0.12);
}
.class-card:has(input:checked)::after {
  content: "";
  position: absolute;
  inset: -80px;
  background: radial-gradient(circle at 30% 30%, rgba(45,212,191,0.18), transparent 55%),
              radial-gradient(circle at 70% 70%, rgba(96,165,250,0.14), transparent 55%);
  animation: floatGlow 2.6s ease-in-out infinite;
}
.class-icon { width: 56px; height: 56px; display: grid; place-items: center; z-index: 1 }
.class-meta { z-index: 1 }
.class-name { font-weight: 800; margin-bottom: 2px }
.class-desc { color: var(--muted); font-size: 13px }
@keyframes floatGlow { 0%,100%{ transform: translate(0,0) } 50%{ transform: translate(10px,-8px) } }
.link { color: var(--primary); text-decoration: none }
.link:hover { text-decoration: underline }
.btn {
  display: inline-block;
  padding: 8px 12px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: rgba(255,255,255,0.06);
  color: var(--text);
  text-decoration: none;
}
.btn:hover { background: rgba(255,255,255,0.10) }
.content { line-height: 1.6 }
.table {
  width: 100%;
  border-collapse: collapse;
  background: rgba(18,24,38,0.72);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.table tbody tr:hover { background: rgba(255,255,255,0.03) }
.table th, .table td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--border);
}
.table thead th { background: rgba(255,255,255,0.06); text-align: left }
.list { list-style: none; padding: 0 }
.list li { padding: 12px 12px; background: rgba(18,24,38,0.72); border: 1px solid var(--border); border-radius: 14px; margin-bottom: 10px }
.form { max-width: 520px; background: rgba(18,24,38,0.72); padding: 20px; border-radius: var(--radius); border: 1px solid var(--border) }
.form label { display: block; margin-bottom: 12px }
.form input, .form select {
  width: 100%; padding: 10px 12px; border-radius: 10px; border: 1px solid var(--border);
  background: #0f172a; color: var(--text);
}
.form textarea {
  width: 100%;
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: #0f172a;
  color: var(--text);
  resize: vertical;
}
.form button {
  background: var(--primary); color: #0b0f19; font-weight: 700; border: none; padding: 10px 14px; border-radius: 10px;
}
.form button:disabled, .form-inline button:disabled { opacity: 0.55; cursor: not-allowed }
.form-inline { display: flex; gap: 10px; align-items: end; background: var(--panel); padding: 16px; border: 1px solid var(--border); border-radius: 12px; margin: 10px 0 }
.form-inline input { width: auto; min-width: 220px }
.form-inline { background: rgba(18,24,38,0.72); border-radius: var(--radius) }
.card { background: rgba(18,24,38,0.72); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px; margin: 16px 0 }
.error { color: #fca5a5; background: rgba(239,68,68,0.12); padding: 8px 10px; border: 1px solid #7f1d1d; border-radius: 8px }
.ok { color: #bbf7d0; background: rgba(34,197,94,0.12); padding: 8px 10px; border: 1px solid #14532d; border-radius: 8px }
.danger { background: var(--danger); color: white }
.success { background: var(--success); color: white }
.footer { text-align: center; color: var(--muted); padding: 34px 24px }
.tabs { margin: 12px 0 16px }