/* ===== CSS Design System - Protein Calculator ===== */

/* Import Google Font */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap');

/* ===== CSS Variables ===== */
:root {
  /* Colors */
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-card: rgba(30, 41, 59, 0.8);
  --bg-card-hover: rgba(30, 41, 59, 0.95);
  
  --accent-primary: #10b981;
  --accent-secondary: #06b6d4;
  --accent-gradient: linear-gradient(135deg, #10b981 0%, #06b6d4 100%);
  
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  
  --border-color: rgba(148, 163, 184, 0.1);
  --shadow-color: rgba(0, 0, 0, 0.3);
  
  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  
  /* Border Radius */
  --radius-sm: 0.5rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;
  --radius-full: 9999px;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 300ms ease;
  --transition-slow: 500ms ease;
}

/* ===== Reset & Base ===== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
}

/* Background Pattern */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: 
    radial-gradient(ellipse at 20% 20%, rgba(16, 185, 129, 0.15) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 80%, rgba(6, 182, 212, 0.15) 0%, transparent 50%),
    radial-gradient(ellipse at 50% 50%, rgba(16, 185, 129, 0.05) 0%, transparent 70%);
  pointer-events: none;
  z-index: -1;
}

a {
  color: inherit;
  text-decoration: none;
}

ul, ol {
  list-style: none;
}

img {
  max-width: 100%;
  height: auto;
}

button {
  cursor: pointer;
  font-family: inherit;
  border: none;
  background: none;
}

input, select, textarea {
  font-family: inherit;
  font-size: inherit;
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  color: var(--text-primary);
}

h1 { font-size: clamp(2rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.5rem, 4vw, 2.5rem); }
h3 { font-size: clamp(1.25rem, 3vw, 1.75rem); }

.gradient-text {
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ===== Layout ===== */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.section {
  padding: var(--spacing-3xl) 0;
}

/* ===== Navigation ===== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: var(--spacing-md) 0;
  background: rgba(15, 23, 42, 0.8);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-color);
  transition: var(--transition-normal);
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: 1.5rem;
  font-weight: 800;
}

.logo-icon {
  font-size: 2rem;
}

.nav-links {
  display: flex;
  gap: var(--spacing-xl);
}

.nav-link {
  position: relative;
  padding: var(--spacing-sm) 0;
  color: var(--text-secondary);
  font-weight: 500;
  transition: var(--transition-fast);
}

.nav-link:hover,
.nav-link.active {
  color: var(--text-primary);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent-gradient);
  transition: var(--transition-normal);
}

.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}

.mobile-menu-btn {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: var(--spacing-sm);
}

.mobile-menu-btn span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  transition: var(--transition-fast);
}

/* ===== Hero Section ===== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: 80px;
}

.hero-content {
  text-align: center;
  max-width: 800px;
  margin: 0 auto;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-lg);
}

.hero-badge-icon {
  color: var(--accent-primary);
}

.hero h1 {
  margin-bottom: var(--spacing-lg);
}

.hero-description {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-2xl);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.hero-buttons {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-xl);
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 1rem;
  transition: var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.btn-primary {
  background: var(--accent-gradient);
  color: var(--bg-primary);
  box-shadow: 0 4px 20px rgba(16, 185, 129, 0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 30px rgba(16, 185, 129, 0.4);
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  backdrop-filter: blur(10px);
}

.btn-secondary:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent-primary);
}

.btn-lg {
  padding: var(--spacing-lg) var(--spacing-2xl);
  font-size: 1.125rem;
}

/* ===== Cards ===== */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  backdrop-filter: blur(20px);
  transition: var(--transition-normal);
}

.card:hover {
  background: var(--bg-card-hover);
  border-color: rgba(16, 185, 129, 0.3);
  transform: translateY(-4px);
  box-shadow: 0 20px 40px var(--shadow-color);
}

/* Feature Cards */
.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-xl);
  margin-top: var(--spacing-2xl);
}

.feature-card {
  text-align: center;
}

.feature-icon {
  width: 80px;
  height: 80px;
  margin: 0 auto var(--spacing-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
  background: var(--accent-gradient);
  border-radius: var(--radius-lg);
  box-shadow: 0 10px 30px rgba(16, 185, 129, 0.2);
}

.feature-card h3 {
  margin-bottom: var(--spacing-sm);
}

.feature-card p {
  color: var(--text-secondary);
}

/* ===== Food Cards Grid ===== */
.food-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--spacing-lg);
}

.food-card {
  position: relative;
  overflow: hidden;
}

.food-emoji {
  font-size: 4rem;
  margin-bottom: var(--spacing-md);
  display: block;
}

.food-name {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
}

.food-category {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-sm);
  background: rgba(16, 185, 129, 0.1);
  color: var(--accent-primary);
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 500;
  margin-bottom: var(--spacing-md);
}

.food-stats {
  display: flex;
  justify-content: space-between;
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--border-color);
}

.food-stat {
  text-align: center;
}

.food-stat-value {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent-primary);
}

.food-stat-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* ===== Search & Filter ===== */
.search-section {
  margin-bottom: var(--spacing-2xl);
}

.search-container {
  display: flex;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

.search-input-wrapper {
  flex: 1;
  min-width: 250px;
  position: relative;
}

.search-icon {
  position: absolute;
  left: var(--spacing-md);
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  font-size: 1.25rem;
}

.search-input {
  width: 100%;
  padding: var(--spacing-md) var(--spacing-md) var(--spacing-md) 3rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  transition: var(--transition-fast);
}

.search-input:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.1);
}

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

.filter-buttons {
  display: flex;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

.filter-btn {
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
  transition: var(--transition-fast);
}

.filter-btn:hover,
.filter-btn.active {
  background: var(--accent-primary);
  border-color: var(--accent-primary);
  color: var(--bg-primary);
}

/* ===== Calculator Form ===== */
.calculator-container {
  max-width: 700px;
  margin: 0 auto;
}

.calculator-form {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.form-label {
  font-weight: 500;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.form-label-icon {
  color: var(--accent-primary);
}

.form-input,
.form-select {
  padding: var(--spacing-md);
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 1rem;
  transition: var(--transition-fast);
}

.form-input:focus,
.form-select:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.1);
}

.form-row {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--spacing-md);
}

/* Radio Group */
.radio-group {
  display: flex;
  gap: var(--spacing-md);
}

.radio-label {
  flex: 1;
  position: relative;
  cursor: pointer;
}

.radio-label input {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
}

.radio-box {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md);
  background: var(--bg-secondary);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  transition: var(--transition-fast);
}

.radio-label input:checked + .radio-box {
  border-color: var(--accent-primary);
  background: rgba(16, 185, 129, 0.1);
}

.radio-icon {
  font-size: 1.5rem;
}

/* ===== Results Section ===== */
.result-section {
  margin-top: var(--spacing-2xl);
  display: none;
}

.result-section.show {
  display: block;
  animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.result-card {
  text-align: center;
  background: linear-gradient(135deg, rgba(16, 185, 129, 0.1) 0%, rgba(6, 182, 212, 0.1) 100%);
  border: 1px solid rgba(16, 185, 129, 0.3);
}

.result-value {
  font-size: 4rem;
  font-weight: 800;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--spacing-sm);
}

.result-unit {
  font-size: 1.5rem;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-lg);
}

.result-details {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-md);
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--border-color);
}

.result-detail {
  text-align: center;
}

.result-detail-value {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--accent-secondary);
}

.result-detail-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
}

/* ===== Page Header ===== */
.page-header {
  padding-top: 120px;
  padding-bottom: var(--spacing-2xl);
  text-align: center;
}

.page-header h1 {
  margin-bottom: var(--spacing-md);
}

.page-header p {
  color: var(--text-secondary);
  font-size: 1.125rem;
  max-width: 600px;
  margin: 0 auto;
}

/* ===== Footer ===== */
.footer {
  padding: var(--spacing-2xl) 0;
  border-top: 1px solid var(--border-color);
  text-align: center;
  color: var(--text-muted);
}

.footer-text {
  font-size: 0.875rem;
}

.footer-heart {
  color: #ef4444;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--bg-primary);
    padding: var(--spacing-lg);
    gap: var(--spacing-md);
    border-bottom: 1px solid var(--border-color);
  }
  
  .nav-links.active {
    display: flex;
  }
  
  .mobile-menu-btn {
    display: flex;
  }
  
  .form-row {
    grid-template-columns: 1fr;
  }
  
  .radio-group {
    flex-direction: column;
  }
  
  .result-details {
    grid-template-columns: 1fr;
  }
  
  .hero-buttons {
    flex-direction: column;
    align-items: center;
  }
  
  .btn-lg {
    width: 100%;
    max-width: 300px;
  }
}

/* ===== Utility Classes ===== */
.text-center { text-align: center; }
.text-left { text-align: left; }
.mt-1 { margin-top: var(--spacing-md); }
.mt-2 { margin-top: var(--spacing-xl); }
.mb-1 { margin-top: var(--spacing-md); }
.mb-2 { margin-top: var(--spacing-xl); }

/* ===== Scrollbar ===== */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
  background: var(--text-muted);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-secondary);
}