/* Reset & Base Setup */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Calibri', 'Poppins', sans-serif;
}

.hidden {
  display: none;
}

body {
  letter-spacing: 0.5px;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
  transition: background-color 0.4s ease, color 0.4s ease;
  animation: backgroundPulse 5s linear infinite;
}

/* Container & Card Styling */
.container {
  width: 100%;
  max-width: 400px;
  padding: 20px;
}

.tip-card {
  border-radius: 15px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
  padding: 30px;
  transition: all 0.3s ease;
}

/* Header */
.card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}

.card-header h1 {
  font-size: 24px;
}

/* Input Fields & Select */
.input-group {
  margin-bottom: 15px;
}

.input-group label {
  font-weight: 600;
  margin-bottom: 5px;
  display: block;
}

.input-group input,
.input-group select {
  width: 100%;
  padding: 12px;
  border-radius: 8px;
  border: 1px solid;
  font-size: 16px;
}

/* Button Group */
.button-group {
  display: flex;
  gap: 10px;
  margin-top: 15px;
}

.btn {
  flex: 1;
  padding: 15px;
  border: none;
  color: #ffffff;
  border-radius: 8px;
  font-size: 16px;
  cursor: pointer;
  transition: background-color 0.3s;
}

.calculate-btn:hover,
.reset-btn:hover,
.recalculate-btn:hover {
  filter: brightness(0.9);
}

/* Results */
.results {
  margin-top: 20px;
}

.result-item {
  display: flex;
  justify-content: space-between;
  margin-bottom: 8px;
  font-size: 18px;
}

/* Checkbox */
.checkbox-group {
  margin-top: 15px;
}

/* Inline Label with Checkbox */
.inline-label {
  display: flex;
  align-items: flex-start;
  gap: 6px;
  padding: 10px 0;
  font-size: 16px;
}

.inline-label input[type="checkbox"] {
  width: 18px;
  height: 18px;
  margin-top: 6px;
  accent-color: inherit;
}

/* Confirmation */
.confirmation-message {
  margin-top: 12px;
  padding: 8px 12px;
  border-radius: 4px;
  font-weight: 500;
  animation: fadeIn 0.6s ease-out;
}

.calculate-btn { 
  background-color: #4caf50; 
}

.reset-btn { 
  background-color: #f44336; 
}

.recalculate-btn { 
  background-color: #C83F12; 
}

/* Animations */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-5px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes backgroundPulse {
  0%   { background-color: #0b0f1a; }   
  25%  { background-color: #0b1b47; } 
  50%  { background-color: #142d68; } 
  75%  { background-color: #1d3a73; }
  100% { background-color: #0b0f1a; }
}