:root {
  --bg: #0f1115;
  --fg: #e7e9ee;
  --card: #161a22;
  --brand: #8b5cf6;
  --accent: #22d3ee;
  --top-gradient-dark: linear-gradient(120deg, #1a1f2e, #12202f, #1d1633);
  --top-gradient-light: linear-gradient(120deg, #e0e7ff, #f0f9ff, #fafafa);
}
:root.light {
  --bg: #f6f7fb;
  --fg: #0d0f14;
  --card: #ffffff;
}
body { background: var(--bg); color: var(--fg); font-family: Arial, sans-serif; margin: 0; }
.top-frame {
  height: 400px;
  display: grid;
  place-items: center;
  background: var(--top-gradient-dark);
  background-size: 200% 200%;
  animation: gradientShift 18s ease infinite;
}
:root.light .top-frame { background: var(--top-gradient-light); }
@keyframes gradientShift {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}
.bottom-frame { padding: 20px; text-align: center; transition: background 0.3s; }
.tab { margin: 0 5px; padding: 8px 16px; border: none; border-radius: 10px; background: var(--card); color: var(--fg); cursor: pointer; }
.tab.active { border: 2px solid var(--brand); }
.card { background: var(--card); padding: 20px; border-radius: 16px; margin-top: 15px; color: var(--fg); }
.btn { background: linear-gradient(90deg, var(--brand), var(--accent)); color: #fff; border: none; padding: 8px 14px; border-radius: 10px; cursor: pointer; }
.btn.ghost { background: transparent; border: 1px solid var(--fg); }
.icon-btn { border: none; background: rgba(255,255,255,0.1); color: #fff; border-radius: 10px; width: 40px; height: 40px; cursor: pointer; }
.modal-overlay { display: none; position: fixed; inset: 0; background: rgba(0,0,0,0.6); justify-content: center; align-items: center; z-index: 10; }
.modal-overlay.open { display: flex; }
.modal-card { background: var(--card); color: var(--fg); border-radius: 14px; padding: 20px; width: 320px; transition: background 0.3s, color 0.3s; }