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

/* Body */
body {
  font-family: "Inter", Arial, sans-serif;
  line-height: 1.7;
  background: #ffffff;
  color: #111111;
  -webkit-font-smoothing: antialiased;
}

/* Header */
header {
  background: linear-gradient(135deg, #111111, #333333);
  color: #ffffff;
  padding: 1.2rem 2rem;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  border-bottom: 3px solid #111111;
}

header h1 {
  font-size: 1.8rem;
  letter-spacing: -0.5px;
  margin: 0;
  justify-self: start;
}

/* Navigation */
nav {
  display: flex;
  gap: 1.5rem;
  justify-self: center;
}

nav a {
  color: #ffffff;
  text-decoration: none;
  font-weight: 500;
  position: relative;
  transition: color 0.3s ease;
}

nav a::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0%;
  height: 2px;
  background: #ffffff;
  transition: width 0.3s ease;
}

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

/* Layout */
main {
  max-width: 1000px;
  margin: 3rem auto;
  padding: 0 1.5rem;
}

/* Hero */
.hero {
  text-align: center;
  margin-bottom: 3rem;
}

.hero h2 {
  font-size: 2.5rem;
  font-weight: 700;
  color: #111111;
}

.hero p {
  font-size: 1.2rem;
  margin-top: 0.8rem;
  color: #444444;
}

/* Sections & Cards */
.intro, .app, section {
  background: #ffffff;
  padding: 2rem;
  margin-bottom: 2rem;
  border-radius: 16px;
  box-shadow: 0 6px 20px rgba(0,0,0,0.08);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.intro:hover, .app:hover, section:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 28px rgba(0,0,0,0.12);
}

/* Lists */
ul {
  list-style-type: disc;
  padding-left: 1.5rem;
}

.app-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1rem;
}

.app-logo {
  width: 64px;
  height: 64px;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

/* Footer */
footer {
  text-align: center;
  padding: 1.5rem;
  background: #111111;
  color: #ffffff;
  margin-top: 3rem;
  font-size: 0.9rem;
  letter-spacing: 0.5px;
}