:root {
  --primary: #1a5f7a;
  --primary-light: #2d8bad;
  --secondary: #c82121;
  --bg: #f8fafc;
  --text: #1e293b;
  --text-muted: #64748b;
  --white: #ffffff;
  --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --border: #e2e8f0;
  --max-width: 1000px;
}

* {
  box-sizing: border-box;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6;
  color: var(--text);
  background-color: var(--bg);
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* Header & Nav */
header {
  background-color: var(--white);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 1px 2px 0 rgb(0 0 0 / 0.05);
}

nav {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
  height: 70px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

nav ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  gap: 24px;
}

nav a {
  text-decoration: none;
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.95rem;
  transition: color 0.2s;
}

nav a:hover, nav a[aria-current="page"] {
  color: var(--primary);
}

/* Main Content */
main {
  flex: 1;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 40px 20px;
  width: 100%;
}

h1, h2, h3 {
  color: var(--text);
  line-height: 1.2;
}

h1 { font-size: 2.5rem; margin-bottom: 1.5rem; }
h2 { font-size: 1.8rem; margin-top: 2rem; margin-bottom: 1rem; border-left: 4px solid var(--primary); padding-left: 15px; }

article {
  background: var(--white);
  padding: 40px;
  border-radius: 12px;
  box-shadow: var(--shadow);
}

/* Hero Section */
#hero {
  text-align: center;
  padding: 60px 0;
  max-width: 800px;
  margin: 0 auto;
}

#hero img {
  border-radius: 24px;
  box-shadow: var(--shadow);
  margin-bottom: 24px;
}

#hero p {
  font-size: 1.25rem;
  color: var(--text-muted);
  margin-bottom: 32px;
}

.play-store-badge {
  display: inline-block;
  transition: transform 0.2s;
}

.play-store-badge:hover {
  transform: scale(1.05);
}

/* Utility Items */
.utility-item h4 {
  color: var(--primary);
  margin-bottom: 8px;
  font-size: 1.1rem;
}

.utility-item p {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin: 0;
}

/* Lists & Tables */
ul, ol {
  padding-left: 1.5rem;
}

li {
  margin-bottom: 0.5rem;
}

/* Footer */
footer {
  background-color: var(--white);
  border-top: 1px solid var(--border);
  padding: 40px 20px;
  margin-top: 60px;
}

footer nav {
  height: auto;
  flex-direction: column;
  gap: 20px;
}

footer ul {
  justify-content: center;
  flex-wrap: wrap;
}

footer p {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-top: 24px;
}

/* Accessibility */
a:focus-visible {
  outline: 3px solid var(--primary-light);
  outline-offset: 2px;
  border-radius: 4px;
}

/* Responsive */
@media (max-width: 640px) {
  h1 { font-size: 2rem; }
  nav { height: auto; padding: 15px 20px; }
  nav ul { gap: 15px; flex-wrap: wrap; justify-content: center; }
  article { padding: 20px; }
}