/* Base Styles & Dark Mode */
:root {
  --primary: #3b82f6; --secondary: #60a5fa; --accent: #ef4444;
  --bg-light: #f3f4f6; --bg-dark: #111827;
  --text-light: #1f2937; --text-dark: #f9fafb;
  --card-light: #ffffff; --card-dark: #1f2937;
  --border-light: #d1d5db; --border-dark: #4b5563;
}

body {
  background: var(--bg-light);
  color: var(--text-light);
  font-family: 'Segoe UI', sans-serif;
  transition: background 0.3s, color 0.3s;
}

body.dark-mode {
  background: var(--bg-dark);
  color: var(--text-dark);
}

.dark-mode .card {
  background: var(--card-dark) !important;
}

.dark-mode input, .dark-mode select {
  background: var(--card-dark);
  color: var(--text-dark);
  border-color: var(--border-dark);
}

.calculator {
  background: var(--card-light);
  padding: 2rem;
  border-radius: 12px;
  box-shadow: 0 6px 15px rgba(0,0,0,0.1);
  max-width: 450px;
  margin: auto;
}

.input-field {
  width: 100%;
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px solid var(--border-light);
  transition: border-color 0.2s;
}

.input-field:focus {
  outline: none;
  border-color: var(--primary);
}

.result-box {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px;
  background: var(--bg-light);
  border-radius: 8px;
}

.dark-mode .result-box {
  background: #2d3748;
}

.result-value {
  font-weight: 700;
  font-size: 1.125rem;
}

.result-profit {
  color: #22c55e;
}

.result-loss {
  color: #ef4444;
}

.faq-item {
  border-bottom: 1px solid var(--border-light);
  padding-bottom: 1rem;
}

.faq-item:last-child {
  border-bottom: none;
}

.faq-item h4 {
  user-select: none;
}

.faq-item h4:hover svg {
  transform: translateY(2px);
}