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

:root {
  /* Colors - Apple Style */
  --primary: #0071E3; /* Apple Blue */
  --primary-hover: #0077ED;
  --primary-light: #E8F0FE;
  
  --bg-color: #FFFFFF;
  --bg-secondary: #F5F5F7; /* Apple subtle gray background */
  
  --text-main: #1D1D1F; /* Apple black */
  --text-muted: #86868B; /* Apple gray text */
  
  --border-color: #D2D2D7;
  
  --card-bg: #FFFFFF;
  --card-shadow: 0 4px 24px rgba(0, 0, 0, 0.04);
  --card-shadow-hover: 0 10px 40px rgba(0, 0, 0, 0.08);
  
  /* Typography - Inter (Apple-like but cross-platform) */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  
  /* Spacing & Layout */
  --container-width: 1280px;
  --section-padding: 100px 24px;
  
  /* Transitions */
  --transition-fast: 0.2s cubic-bezier(0.25, 0.1, 0.25, 1);
  --transition-normal: 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  --transition-slow: 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

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

html {
  scroll-behavior: smooth;
  font-family: var(--font-sans);
  color: var(--text-main);
  background-color: var(--bg-color);
  line-height: 1.47059;
  font-weight: 400;
  letter-spacing: -0.022em;
  -webkit-font-smoothing: antialiased;
}

body {
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

main {
  flex-grow: 1;
}

a {
  text-decoration: none;
  color: inherit;
  transition: color var(--transition-fast);
}

img, svg {
  max-width: 100%;
  height: auto;
  display: block;
}

ul {
  list-style: none;
}

h1, h2, h3, h4, h5, h6 {
  line-height: 1.07143;
  font-weight: 600;
  color: var(--text-main);
  letter-spacing: -0.005em;
}

h1 {
  font-size: clamp(3rem, 6vw, 5.5rem);
  font-weight: 700;
  letter-spacing: -0.015em;
}

h2 {
  font-size: clamp(2.5rem, 5vw, 4rem);
  font-weight: 600;
  letter-spacing: -0.005em;
}

p {
  color: var(--text-muted);
  font-size: 1.17647rem; /* ~20px */
  font-weight: 400;
  letter-spacing: 0.011em;
  max-width: 680px;
}

/* Layout Utilities */
.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: var(--section-padding);
}

.section-light {
  background-color: var(--bg-secondary);
}

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

.flex-center {
  display: flex;
  align-items: center;
  justify-content: center;
}

.gradient-text {
  background: linear-gradient(90deg, #0071E3, #34C759, #FF9500, #FF3B30);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

/* Micro-animations */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}

.animate-fade-in {
  animation: fadeIn var(--transition-slow) forwards;
  opacity: 0;
}

.delay-100 { animation-delay: 150ms; }
.delay-200 { animation-delay: 300ms; }
.delay-300 { animation-delay: 450ms; }
.delay-400 { animation-delay: 600ms; }
.delay-500 { animation-delay: 750ms; }

/* Responsive padding — giảm section padding trên màn hình nhỏ hơn */
@media (max-width: 1280px) {
  :root {
    --section-padding: 80px 24px;
  }
}

@media (max-width: 768px) {
  :root {
    --section-padding: 60px 20px;
  }
}