/* Minimal styles for initial calculator layout */
body {
  font-family: Arial, sans-serif;
  background: #f3f4f6;
  color: #111827;
  margin: 0;
  padding: 20px;
}
.container {
  max-width: 900px;
  margin: 0 auto;
  display: flex;
  gap: 20px;
}
.header-row { display:flex; justify-content:space-between; align-items:center; }
.user-bar { font-size:14px; }
.user-bar button { margin-left:8px; }
#calculator-root {
  flex: 1 1 600px;
  background: #fff;
  padding: 16px;
  border-radius: 8px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.08);
}
.display {
  height: 60px;
  background: #0f172a;
  color: #fff;
  font-size: 28px;
  display: flex;
  align-items: center;
  justify-content: flex-end;
  padding: 8px 12px;
  border-radius: 6px;
}
#history-panel {
  width: 260px;
  background: #fff;
  padding: 12px;
  border-radius: 8px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.06);
}

/* Calculator styling */
.calculator {
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.pad {
  display: grid;
  grid-template-columns: repeat(4, 72px);
  gap: 8px;
}
.btn {
  height: 52px;
  border-radius: 6px;
  border: none;
  background: #e5e7eb;
  font-size: 18px;
  cursor: pointer;
}
.btn:hover { filter: brightness(0.98); }
.btn-op { background: #f59e0b; color: #fff; }
.btn-eq { background: #10b981; color: #fff; grid-row: span 1; }
.btn-ac { background: #ef4444; color: #fff; }
.btn.zero { grid-column: span 1; width: 100%; }

.history-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
#history-list { list-style: none; padding: 0; margin-top: 8px; }
#history-list li { padding: 6px 4px; border-bottom: 1px solid #f1f5f9; font-size: 14px; }