.guru-calculator {
  --guru-primary: #10b981;
  --guru-primary-hover: #059669;
  --guru-text: #1e293b;
  --guru-text-muted: #64748b;
  --guru-bg: #ffffff;
  --guru-border: #e2e8f0;
  --guru-radius: 8px;

  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  color: var(--guru-text);
  background: var(--guru-bg);
  border: 1px solid var(--guru-border);
  border-radius: var(--guru-radius);
  padding: 24px;
  max-width: 400px;
  box-sizing: border-box;
}

.guru-calculator *,
.guru-calculator *::before,
.guru-calculator *::after {
  box-sizing: border-box;
}

.guru-calculator__title {
  font-size: 18px;
  font-weight: 600;
  margin: 0 0 20px 0;
  text-align: center;
}

.guru-calculator__field {
  margin-bottom: 20px;
}

.guru-calculator__label {
  display: block;
  font-size: 14px;
  font-weight: 500;
  color: var(--guru-text-muted);
  margin-bottom: 8px;
}

.guru-calculator__input-group {
  display: flex;
  align-items: center;
  gap: 8px;
}

.guru-calculator__btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border: 1px solid var(--guru-border);
  border-radius: var(--guru-radius);
  background: var(--guru-bg);
  cursor: pointer;
  font-size: 18px;
  color: var(--guru-text);
  transition: background 0.15s;
  flex-shrink: 0;
  user-select: none;
  -webkit-user-select: none;
}

.guru-calculator__btn:hover {
  background: #f1f5f9;
}

.guru-calculator__btn:active {
  background: #e2e8f0;
}

.guru-calculator__value {
  flex: 1;
  text-align: center;
  font-size: 24px;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  border: 1px solid var(--guru-border);
  border-radius: var(--guru-radius);
  padding: 6px 8px;
  background: transparent;
  color: var(--guru-text);
  width: 100%;
  min-width: 0;
  -moz-appearance: textfield;
}

.guru-calculator__value::-webkit-outer-spin-button,
.guru-calculator__value::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.guru-calculator__value:focus {
  outline: 2px solid var(--guru-primary);
  outline-offset: -1px;
  border-color: transparent;
}

.guru-calculator__unit {
  font-size: 14px;
  color: var(--guru-text-muted);
  flex-shrink: 0;
}

.guru-calculator__savings {
  background: #f0fdf4;
  border: 1px solid #bbf7d0;
  border-radius: var(--guru-radius);
  padding: 16px;
  text-align: center;
  margin-bottom: 20px;
}

.guru-calculator__savings--zero {
  background: #f8fafc;
  border-color: var(--guru-border);
}

.guru-calculator__savings-amount {
  font-size: 28px;
  font-weight: 700;
  color: var(--guru-primary);
  font-variant-numeric: tabular-nums;
}

.guru-calculator__savings--zero .guru-calculator__savings-amount {
  color: var(--guru-text-muted);
}

.guru-calculator__savings-label {
  font-size: 13px;
  color: var(--guru-text-muted);
  margin-top: 4px;
}

.guru-calculator__cta {
  display: block;
  width: 100%;
  padding: 12px 24px;
  background: var(--guru-primary);
  color: #ffffff;
  border: none;
  border-radius: var(--guru-radius);
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  text-align: center;
  text-decoration: none;
  transition: background 0.15s;
}

.guru-calculator__cta:hover {
  background: var(--guru-primary-hover);
}