/* ===========================
   Reset & Base
=========================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: #1a1a1a;
  background-color: #ffffff;
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ===========================
   Header & Nav
=========================== */
header {
  background-color: #ffffff;
  border-bottom: 1px solid #e5e5e5;
  padding: 0 2rem;
  position: sticky;
  top: 0;
  z-index: 100;
}

nav {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.site-name {
  font-weight: 700;
  font-size: 1.1rem;
  color: #1a1a1a;
}

nav ul {
  list-style: none;
  display: flex;
  gap: 2rem;
}

nav ul a {
  text-decoration: none;
  color: #555;
  font-size: 0.95rem;
  transition: color 0.2s;
}

nav ul a:hover {
  color: #0066ff;
}

/* ===========================
   Main & Hero
=========================== */
main {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 4rem 2rem;
}

.hero {
  max-width: 640px;
  text-align: center;
}

.hero h1 {
  font-size: 3rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 1rem;
  color: #0a0a0a;
}

.hero p {
  font-size: 1.15rem;
  color: #555;
  margin-bottom: 2rem;
}

/* ===========================
   Button
=========================== */
.btn {
  display: inline-block;
  padding: 0.75rem 1.75rem;
  background-color: #0066ff;
  color: #ffffff;
  text-decoration: none;
  border-radius: 6px;
  font-size: 0.95rem;
  font-weight: 600;
  transition: background-color 0.2s, transform 0.1s;
}

.btn:hover {
  background-color: #0052cc;
  transform: translateY(-1px);
}

/* ===========================
   Footer
=========================== */
footer {
  text-align: center;
  padding: 1.5rem 2rem;
  font-size: 0.85rem;
  color: #999;
  border-top: 1px solid #e5e5e5;
}