/* Yolkil - Structured Research Layout Design System */

:root {
  --primary-color: #2C3E50;
  --secondary-color: #ECF0F1;
  --accent-orange: #F39C12;
  --accent-green: #27AE60;
  --neutral-silver: #BDC3C7;
  --neutral-platinum: #D0D3D4;
  --dark-teal: #34495E;
  --base-spacing: 8px;
  --max-container-width: 1280px;
  --text-container-width: 960px;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Roboto', 'Open Sans', sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: #2C3E50;
  background-color: #fff;
}

/* Typography System */
h1 {
  font-family: 'Lora', 'Merriweather Sans', serif;
  font-size: 3.5rem;
  font-weight: 500;
  line-height: 1.2;
  color: var(--primary-color);
  margin-bottom: calc(var(--base-spacing) * 6);
  text-balance: balance;
}

h2 {
  font-family: 'Lora', 'Merriweather Sans', serif;
  font-size: 2.25rem;
  font-weight: 500;
  line-height: 1.3;
  color: var(--primary-color);
  margin-bottom: calc(var(--base-spacing) * 4);
  text-balance: balance;
}

h3 {
  font-family: 'Lora', 'Merriweather Sans', serif;
  font-size: 1.5rem;
  font-weight: 500;
  line-height: 1.4;
  color: var(--primary-color);
  margin-bottom: calc(var(--base-spacing) * 3);
  text-balance: balance;
}

p {
  margin-bottom: calc(var(--base-spacing) * 3);
  line-height: 1.6;
  color: #34495E;
}

a {
  color: var(--accent-orange);
  text-decoration: none;
  transition: all 0.3s ease;
}

a:hover {
  text-decoration: underline;
  color: var(--dark-teal);
}

/* Header & Navigation */
header {
  background-color: var(--primary-color);
  color: white;
  padding: calc(var(--base-spacing) * 2) calc(var(--base-spacing) * 3);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.header-container {
  max-width: var(--max-container-width);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: 600;
  color: white;
  letter-spacing: 1px;
}

nav ul {
  list-style: none;
  display: flex;
  gap: calc(var(--base-spacing) * 4);
  flex-wrap: wrap;
}

nav a {
  color: white;
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s ease;
}

nav a:hover,
nav a.active {
  color: var(--accent-orange);
  text-decoration: underline;
}

/* Main Container */
.container {
  max-width: var(--text-container-width);
  margin: 0 auto;
  padding: 0 calc(var(--base-spacing) * 3);
}

.container-full {
  max-width: 100%;
}

/* Spacing System */
.section {
  padding: calc(var(--base-spacing) * 10) 0;
  border-bottom: 1px solid var(--neutral-platinum);
}

.section:last-child {
  border-bottom: none;
}

.section-hero {
  padding: calc(var(--base-spacing) * 15) 0;
  background: linear-gradient(rgba(44, 62, 80, 0.7), rgba(44, 62, 80, 0.7)), 
              url('/images/hero-nutrition.jpg');
  background-size: cover;
  background-position: center;
  color: white;
  text-align: center;
  position: relative;
}

.section-hero h1 {
  color: white;
  font-size: 4rem;
  margin-bottom: calc(var(--base-spacing) * 4);
}

.section-hero p {
  color: #ECF0F1;
  font-size: 1.2rem;
  max-width: 800px;
  margin: 0 auto calc(var(--base-spacing) * 4);
}

/* Research Panel Layout */
.research-panel {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: calc(var(--base-spacing) * 6);
  align-items: center;
  margin-bottom: calc(var(--base-spacing) * 12);
}

.research-panel.reverse {
  direction: rtl;
}

.research-panel.reverse > * {
  direction: ltr;
}

.research-panel-text {
  padding: calc(var(--base-spacing) * 4);
}

.research-panel-image {
  position: relative;
  overflow: hidden;
  border-radius: 4px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
}

.research-panel-image img {
  width: 100%;
  height: auto;
  display: block;
}

/* Cards Grid */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: calc(var(--base-spacing) * 6);
  margin-bottom: calc(var(--base-spacing) * 8);
}

.card {
  background: var(--secondary-color);
  border: 1px solid var(--neutral-platinum);
  padding: calc(var(--base-spacing) * 4);
  border-radius: 4px;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.08);
  transition: all 0.3s ease;
}

.card:hover {
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.12);
  transform: translateY(-2px);
}

.card h3 {
  margin-bottom: calc(var(--base-spacing) * 2);
}

.card p {
  font-size: 0.9rem;
  line-height: 1.5;
}

/* Accent Box */
.accent-box {
  background-color: #E8F4F8;
  border-left: 4px solid var(--accent-green);
  padding: calc(var(--base-spacing) * 4);
  margin: calc(var(--base-spacing) * 6) 0;
  border-radius: 2px;
}

.accent-box.warning {
  background-color: #FEF5E7;
  border-left-color: var(--accent-orange);
}

.accent-box h4 {
  color: var(--primary-color);
  margin-bottom: calc(var(--base-spacing) * 2);
  font-weight: 600;
}

/* Lists */
ul, ol {
  margin-left: calc(var(--base-spacing) * 4);
  margin-bottom: calc(var(--base-spacing) * 4);
  line-height: 1.8;
}

li {
  margin-bottom: calc(var(--base-spacing) * 2);
}

/* Buttons */
.btn {
  display: inline-block;
  padding: calc(var(--base-spacing) * 2.5) calc(var(--base-spacing) * 6);
  background-color: transparent;
  border: 2px solid var(--accent-orange);
  color: var(--accent-orange);
  text-decoration: none;
  font-weight: 600;
  border-radius: 2px;
  transition: all 0.3s ease;
  cursor: pointer;
  font-family: 'Roboto', 'Open Sans', sans-serif;
  font-size: 1rem;
}

.btn:hover {
  background-color: var(--accent-orange);
  color: white;
  box-shadow: 0 4px 12px rgba(243, 156, 18, 0.3);
}

.btn:active {
  opacity: 0.95;
}

.btn-secondary {
  border-color: var(--accent-green);
  color: var(--accent-green);
}

.btn-secondary:hover {
  background-color: var(--accent-green);
  color: white;
  box-shadow: 0 4px 12px rgba(39, 174, 96, 0.3);
}

/* Footer */
footer {
  background-color: var(--primary-color);
  color: white;
  padding: calc(var(--base-spacing) * 10) calc(var(--base-spacing) * 3);
  margin-top: calc(var(--base-spacing) * 15);
}

.footer-container {
  max-width: var(--max-container-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: calc(var(--base-spacing) * 6);
  margin-bottom: calc(var(--base-spacing) * 6);
}

.footer-section h4 {
  color: white;
  margin-bottom: calc(var(--base-spacing) * 3);
  font-size: 1rem;
  font-weight: 600;
}

.footer-section ul {
  list-style: none;
  margin: 0;
}

.footer-section a {
  color: #ECF0F1;
  text-decoration: none;
}

.footer-section a:hover {
  color: var(--accent-orange);
}

.footer-bottom {
  max-width: var(--max-container-width);
  margin: 0 auto;
  padding-top: calc(var(--base-spacing) * 6);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  text-align: center;
  font-size: 0.9rem;
  color: #BDC3C7;
}

/* Forms */
.form-group {
  margin-bottom: calc(var(--base-spacing) * 4);
}

.form-group label {
  display: block;
  margin-bottom: calc(var(--base-spacing) * 1.5);
  font-weight: 600;
  color: var(--primary-color);
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: calc(var(--base-spacing) * 2.5);
  border: 1px solid var(--neutral-platinum);
  border-radius: 4px;
  font-family: inherit;
  font-size: 1rem;
  transition: all 0.3s ease;
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--accent-orange);
  box-shadow: 0 0 0 3px rgba(243, 156, 18, 0.1);
}

/* Responsive Design */
@media (max-width: 768px) {
  h1 {
    font-size: 2.5rem;
  }

  h2 {
    font-size: 1.75rem;
  }

  h3 {
    font-size: 1.25rem;
  }

  .research-panel {
    grid-template-columns: 1fr;
    gap: calc(var(--base-spacing) * 4);
  }

  nav ul {
    gap: calc(var(--base-spacing) * 2);
  }

  .section-hero h1 {
    font-size: 2.5rem;
  }

  .cards-grid {
    grid-template-columns: 1fr;
  }

  .footer-container {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  h1 {
    font-size: 2rem;
  }

  h2 {
    font-size: 1.5rem;
  }

  .header-container {
    flex-wrap: wrap;
  }

  nav ul {
    width: 100%;
    justify-content: flex-start;
  }

  .btn {
    padding: calc(var(--base-spacing) * 2) calc(var(--base-spacing) * 4);
    font-size: 0.9rem;
  }
}

/* Utility Classes */
.text-center {
  text-align: center;
}

.text-muted {
  color: var(--neutral-silver);
}

.mt-4 {
  margin-top: calc(var(--base-spacing) * 4);
}

.mb-4 {
  margin-bottom: calc(var(--base-spacing) * 4);
}

.py-6 {
  padding-top: calc(var(--base-spacing) * 6);
  padding-bottom: calc(var(--base-spacing) * 6);
}

.hidden {
  display: none;
}

/* Accessibility */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}