/* ==========================================================================
   RESET & VARIABLES
   ========================================================================== */
:root {
  /* Colors */
  --color-white: #ffffff;
  --color-black: #111111;
  --color-gray-light: #f5f5f7;
  --color-gray-dark: #666666;
  --color-blue: #31ADFF;
  /* Main accent color */
  --color-blue-hover: #1d95e0;

  /* Typography */
  --font-main: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;

  /* Borders & Shadows */
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;
  --radius-pill: 9999px;

  --shadow-sm: 0 4px 6px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.1);

  /* Glassmorphism */
  --glass-bg: rgba(255, 255, 255, 0.7);
  --glass-border: rgba(255, 255, 255, 0.3);
  --glass-blur: blur(20px);
}

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

body {
  font-family: var(--font-main);
  background-color: var(--color-gray-light);
  color: var(--color-black);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  text-decoration: none;
  color: inherit;
  transition: all 0.3s ease;
}

ul {
  list-style: none;
}

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

/* ==========================================================================
   UTILITY CLASSES
   ========================================================================== */

.container {
  width: 100%;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Card Concept */
.card {
  background-color: var(--color-white);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-md);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

.radius-round {
  border-radius: var(--radius-xl);
}

.overflow-hidden {
  overflow: hidden;
}

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

/* Typography Utilities */
.h1 {
  font-size: clamp(2.5rem, 5vw, 4.5rem);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.02em;
  margin-bottom: 24px;
}

.h2 {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.01em;
  margin-bottom: 20px;
}

.h3 {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 16px;
}

.text-muted {
  color: var(--color-gray-dark);
}

.text-blue {
  color: var(--color-blue);
}

/* Glassmorphism Utilities */
.glass {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-border);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  border-radius: var(--radius-pill);
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  border: none;
  transition: all 0.3s ease;
}

.btn-primary {
  background-color: var(--color-blue);
  color: var(--color-white);
}

.btn-primary:hover {
  background-color: var(--color-blue-hover);
  transform: scale(1.02);
}

.btn-secondary {
  background-color: var(--color-black);
  color: var(--color-white);
}

.btn-secondary:hover {
  background-color: #333;
  transform: scale(1.02);
}

.btn-outline {
  background-color: transparent;
  border: 1px solid var(--color-black);
  color: var(--color-black);
}

.btn-outline:hover {
  background-color: var(--color-black);
  color: var(--color-white);
}

/* Margin/Padding Utilities */
.mt-1 {
  margin-top: 8px;
}

.mt-2 {
  margin-top: 16px;
}

.mt-3 {
  margin-top: 24px;
}

.mt-4 {
  margin-top: 32px;
}

.mt-5 {
  margin-top: 48px;
}

.mt-6 {
  margin-top: 64px;
}

.mt-8 {
  margin-top: 96px;
}

.mb-1 {
  margin-bottom: 8px;
}

.mb-2 {
  margin-bottom: 16px;
}

.mb-3 {
  margin-bottom: 24px;
}

.mb-4 {
  margin-bottom: 32px;
}

.mb-5 {
  margin-bottom: 48px;
}

.mb-6 {
  margin-bottom: 64px;
}

.mb-8 {
  margin-bottom: 96px;
}

.section-padding {
  padding: 96px 0;
}

/* ==========================================================================
   LAYOUT COMPONENTS
   ========================================================================== */

/* Header */
.header {
  position: fixed;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
  width: calc(100% - 48px);
  max-width: 1240px;
  z-index: 1000;
  border-radius: var(--radius-pill);
  padding: 12px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: all 0.3s ease;
}

.header.scrolled {
  box-shadow: var(--shadow-md);
}

.logo {
  font-weight: 700;
  font-size: 1.25rem;
  display: flex;
  align-items: center;
  gap: 8px;
}

.logo-accent {
  color: var(--color-blue);
}

.nav-links {
  display: flex;
  gap: 32px;
  align-items: center;
}

.nav-link {
  font-weight: 500;
  font-size: 0.95rem;
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--color-blue);
  transition: width 0.3s ease;
}

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

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  font-size: 1.5rem;
}

/* Footer */
.footer {
  background-color: var(--color-black);
  color: var(--color-white);
  padding: 64px 0 32px;
  border-top-left-radius: var(--radius-xl);
  border-top-right-radius: var(--radius-xl);
  margin-top: 64px;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 48px;
  margin-bottom: 48px;
}

.footer-col h4 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 24px;
}

.footer-links li {
  margin-bottom: 12px;
}

.footer-links a {
  color: #a3a3a3;
}

.footer-links a:hover {
  color: var(--color-white);
}

.footer-bottom {
  text-align: center;
  padding-top: 32px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  color: #a3a3a3;
  font-size: 0.875rem;
}

/* ==========================================================================
   RESPONSIVE DESIGN
   ========================================================================== */

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: calc(100% + 16px);
    left: 0;
    width: 100%;
    flex-direction: column;
    background-color: var(--color-white);
    padding: 24px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    gap: 16px;
    text-align: center;
  }

  .nav-links.active {
    display: flex;
  }

  .mobile-menu-btn {
    display: block;
  }

  .header {
    top: 12px;
    width: calc(100% - 24px);
  }

  .section-padding {
    padding: 64px 0;
  }
}