/* Professional BMI Calculator - Dark Theme */

/* CSS Variables */
:root {
  --primary-bg: #0a0a0a;
  --secondary-bg: #1a1a1a;
  --tertiary-bg: #2a2a2a;
  --accent-color: #00d4aa;
  --accent-hover: #00f5d4;
  --text-primary: #ffffff;
  --text-secondary: #cccccc;
  --text-muted: #888888;
  --border-color: #333333;
  --border-hover: #444444;
  --success-color: #00d4aa;
  --warning-color: #ffa500;
  --error-color: #ff4757;
  --shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
  --shadow-hover: 0 12px 40px rgba(0, 0, 0, 0.4);
  --border-radius: 12px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Reset and Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: linear-gradient(135deg, var(--primary-bg) 0%, #0f0f0f 50%, var(--primary-bg) 100%);
  background-attachment: fixed;
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 20px;
  line-height: 1.6;
}

.container {
  width: 100%;
  max-width: 800px;
  padding: 0 20px;
}

.calculator {
  background: var(--secondary-bg);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  border: 1px solid var(--border-color);
}

/* Header */
.header {
  background: linear-gradient(135deg, var(--tertiary-bg), var(--secondary-bg));
  padding: 40px 30px;
  text-align: center;
  border-bottom: 1px solid var(--border-color);
}

.header h1 {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 10px;
  background: linear-gradient(135deg, var(--accent-color), var(--accent-hover));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.header p {
  color: var(--text-secondary);
  font-size: 1.1rem;
  font-weight: 400;
}

/* Form Section */
.form-section {
  padding: 30px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.input-group {
  display: flex;
  flex-direction: column;
}

.input-group label {
  font-size: 0.9rem;
  font-weight: 500;
  margin-bottom: 8px;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.input-group input,
.input-group select {
  padding: 16px 20px;
  background: var(--tertiary-bg);
  border: 2px solid var(--border-color);
  border-radius: var(--border-radius);
  color: var(--text-primary);
  font-size: 1rem;
  font-family: inherit;
  transition: var(--transition);
  outline: none;
}

.input-group input:focus,
.input-group select:focus {
  border-color: var(--accent-color);
  box-shadow: 0 0 0 3px rgba(0, 212, 170, 0.1);
  background: var(--secondary-bg);
}

.input-group input::placeholder {
  color: var(--text-muted);
}

/* Calculate Button */
.calculate-btn {
  grid-column: 1 / -1;
  padding: 18px 30px;
  background: linear-gradient(135deg, var(--accent-color), var(--accent-hover));
  border: none;
  border-radius: var(--border-radius);
  color: var(--primary-bg);
  font-size: 1.1rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  text-transform: uppercase;
  letter-spacing: 1px;
  position: relative;
  overflow: hidden;
}

.calculate-btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
  transition: left 0.5s;
}

.calculate-btn:hover::before {
  left: 100%;
}

.calculate-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-hover);
}

.calculate-btn:active {
  transform: translateY(0);
}

/* Results Section */
.results-section {
  padding: 30px;
  background: var(--tertiary-bg);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 30px;
  align-items: center;
}

.result-card {
  background: var(--secondary-bg);
  border-radius: var(--border-radius);
  padding: 25px;
  text-align: center;
  border: 1px solid var(--border-color);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.1);
}

.result-header h3 {
  color: var(--accent-color);
  font-size: 1.2rem;
  margin-bottom: 15px;
  font-weight: 600;
}

.bmi-value {
  font-size: 3rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text-primary);
}

.bmi-category {
  font-size: 1.1rem;
  font-weight: 500;
  padding: 8px 16px;
  border-radius: 20px;
  display: inline-block;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* BMI Categories */
.bmi-category.underweight {
  background: rgba(255, 165, 0, 0.1);
  color: var(--warning-color);
  border: 1px solid var(--warning-color);
}

.bmi-category.normal {
  background: rgba(0, 212, 170, 0.1);
  color: var(--success-color);
  border: 1px solid var(--success-color);
}

.bmi-category.overweight {
  background: rgba(255, 165, 0, 0.1);
  color: var(--warning-color);
  border: 1px solid var(--warning-color);
}

.bmi-category.obese {
  background: rgba(255, 71, 87, 0.1);
  color: var(--error-color);
  border: 1px solid var(--error-color);
}

/* Gauge Container */
.gauge-container {
  display: flex;
  justify-content: center;
  align-items: center;
}

/* History Section */
.history-section {
  padding: 30px;
}

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

.history-header h3 {
  color: var(--accent-color);
  font-size: 1.3rem;
  font-weight: 600;
}

.clear-btn {
  padding: 8px 16px;
  background: var(--error-color);
  border: none;
  border-radius: var(--border-radius);
  color: white;
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.clear-btn:hover {
  background: #ff3742;
  transform: translateY(-1px);
}

.history-list {
  max-height: 300px;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--border-color) var(--tertiary-bg);
}

.history-list::-webkit-scrollbar {
  width: 6px;
}

.history-list::-webkit-scrollbar-track {
  background: var(--tertiary-bg);
  border-radius: 3px;
}

.history-list::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 3px;
}

.history-list::-webkit-scrollbar-thumb:hover {
  background: var(--border-hover);
}

.history-item {
  background: var(--secondary-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: 15px 20px;
  margin-bottom: 10px;
  transition: var(--transition);
  cursor: pointer;
  font-size: 0.9rem;
}

.history-item:hover {
  background: var(--tertiary-bg);
  border-color: var(--border-hover);
  transform: translateX(5px);
}

.history-item:last-child {
  margin-bottom: 0;
}

/* Responsive Design */
@media (max-width: 768px) {
  .form-section {
    grid-template-columns: 1fr;
  }

  .results-section {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .header h1 {
    font-size: 2rem;
  }

  .bmi-value {
    font-size: 2.5rem;
  }

  .history-header {
    flex-direction: column;
    gap: 15px;
    align-items: stretch;
  }

  .clear-btn {
    align-self: flex-end;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 10px;
  }

  .calculator {
    border-radius: 8px;
  }

  .header,
  .form-section,
  .results-section,
  .history-section {
    padding: 20px;
  }

  .header h1 {
    font-size: 1.8rem;
  }

  .bmi-value {
    font-size: 2rem;
  }
}

/* Loading Animation */
@keyframes pulse {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.5;
  }
}

.loading {
  animation: pulse 1.5s ease-in-out infinite;
}

/* Success Animation */
@keyframes success {
  0% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.05);
  }
  100% {
    transform: scale(1);
  }
}

.result-card.success {
  animation: success 0.6s ease-out;
}