:root {
  --primary: #6750a4;
  --on-primary: #ffffff;
  --secondary: #1f1f1f;
  --on-secondary: #ffffff;
  --surface: #ffffff;
  --background: #f4f4f9;
  --text: #1f1f1f;
  --text-secondary: #49454f;
  --hover: #e8def8;
  --shadow: rgba(0, 0, 0, 0.1);
  --success: #388e3c;
  --warning: #fbc02d;
  --danger: #d32f2f;
  --radius: 16px;
  --radius-lg: 32px;
  --transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
  background: var(--background);
  font-family: "Roboto", Arial, sans-serif;
  color: var(--text);
  line-height: 1.6;
}

.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 16px;
}

a {
  text-decoration: none;
  transition: color var(--transition);
}
a:focus {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

/* Header */
header {
  background: var(--surface);
  box-shadow: 0 1px 3px var(--shadow);
  position: sticky;
  top: 0;
  z-index: 10;
  min-height: 64px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: box-shadow var(--transition);
}

.logo {
  font-size: 1.5em;
  font-weight: 500;
  color: var(--primary);
  display: flex;
  align-items: center;
}

.logo i {
  margin-right: 8px;
}

nav {
  display: flex;
  align-items: center;
  transition: all var(--transition);
}

nav a {
  padding: 0 16px;
  color: var(--text-secondary);
  font-weight: 500;
  display: flex;
  align-items: center;
  transition: background var(--transition), color var(--transition);
  border-radius: 999px;
}

nav a i {
  margin-right: 8px;
}

nav a:hover,
nav a:focus {
  background: var(--hover);
  color: var(--primary);
}

.menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 24px;
  color: var(--primary);
  cursor: pointer;
  transition: color var(--transition);
}
.menu-toggle:focus {
  outline: 2px solid var(--primary);
}

/* General Section Styles */
section {
  padding: 64px 0;
  text-align: center;
}

h2 {
  font-size: 2em;
  font-weight: 700;
  margin-bottom: 32px;
  display: flex;
  justify-content: center;
  align-items: center;
}

h2 i {
  margin-right: 12px;
}

.card-grid,
.card-list {
  max-width: 800px;
  margin: 0 auto;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.card-list .card {
  margin-bottom: 16px;
}

.card {
  background: var(--surface);
  padding: 24px;
  border-radius: var(--radius);
  box-shadow: 0 2px 4px var(--shadow);
  transition: box-shadow var(--transition), transform var(--transition);
  text-align: left;
}

.card:hover,
.card:focus-within {
  box-shadow: 0 4px 16px var(--shadow);
  transform: translateY(-2px) scale(1.01);
}

.card i {
  font-size: 2em;
  color: var(--primary);
  margin-bottom: 16px;
  display: block;
}

.card h3 {
  font-size: 1.25em;
  font-weight: 500;
  color: var(--primary);
  margin-bottom: 8px;
}

/* Hero */
.hero {
  background: var(--hover);
  border-radius: 0 0 var(--radius-lg) var(--radius-lg);
  transition: background var(--transition);
}

.hero h1 {
  font-size: 2.5em;
  font-weight: 700;
  margin-bottom: 16px;
}

.hero p {
  font-size: 1.25em;
  margin-bottom: 24px;
}

.button-group {
  display: inline-flex;
  gap: 12px;
  margin-bottom: 24px;
}

.btn {
  padding: 12px 24px;
  font-size: 1.1em;
  font-weight: 500;
  border: none;
  border-radius: 999px;
  cursor: pointer;
  display: flex;
  align-items: center;
  box-shadow: 0 2px 4px var(--shadow);
  transition: box-shadow var(--transition), transform var(--transition),
    background var(--transition), color var(--transition);
}

.btn i {
  margin-right: 8px;
}

.btn:hover,
.btn:focus {
  box-shadow: 0 4px 12px var(--shadow);
  transform: translateY(-2px) scale(1.03);
  outline: none;
}

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

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

.btn-secondary:hover {
  background: #333333;
}

.hero-video {
  max-width: 100%;
  margin-top: 32px;
  border-radius: var(--radius);
  box-shadow: 0 4px 12px var(--shadow);
}

/* About */
.about .button-group {
  justify-content: center;
}

/* Footer */
footer {
  padding: 32px 0;
  font-size: 0.9em;
  color: var(--text-secondary);
}

footer a {
  color: var(--primary);
  font-weight: 500;
}

footer i {
  margin-right: 8px;
  vertical-align: middle;
}

/* Back to Top */
.back-to-top {
  display: none;
  position: fixed;
  bottom: 16px;
  right: 16px;
  background: var(--primary);
  color: var(--on-primary);
  border: none;
  border-radius: 999px;
  width: 48px;
  height: 48px;
  font-size: 24px;
  cursor: pointer;
  box-shadow: 0 2px 4px var(--shadow);
  transition: opacity var(--transition), box-shadow var(--transition);
}

.back-to-top:hover,
.back-to-top:focus {
  opacity: 0.9;
  box-shadow: 0 4px 12px var(--shadow);
  outline: none;
}

/* Responsive */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 2em;
  }

  .hero p {
    font-size: 1em;
  }

  .btn {
    padding: 10px 20px;
    font-size: 1em;
  }

  .button-group {
    flex-direction: column;
    align-items: center;
  }

  .menu-toggle {
    display: block;
  }

  nav {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    width: 100%;
    background: var(--surface);
    flex-direction: column;
    box-shadow: 0 4px 12px var(--shadow);
    border-radius: 0 0 var(--radius) var(--radius);
    transition: all var(--transition);
    z-index: 20;
  }

  nav.active {
    display: flex;
    animation: navFadeIn 0.3s;
  }

  nav a {
    padding: 16px;
    width: 100%;
    justify-content: center;
    border-radius: 0;
  }
}

@keyframes navFadeIn {
  from {
    opacity: 0;
    transform: translateY(-16px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}