:root {
  --purple: #7c3aed;
  --azure: #0ea5e9;
  --bg: #020617;
  --card: #0f172a;
  --text: #f8fafc;
}

* {
  box-sizing: border-box;
  font-family: system-ui, sans-serif;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  text-align: center;
  
}
/* NAVBAR */
.navbar {
  position: fixed;
  top: 0;
  width: 100%;
  background: white;
  padding: 1rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  box-shadow: 0 4px 20px rgba(0,0,0,.08);
  z-index: 10000;
}

.logo {
  font-weight: 900;
  font-size: 1.4rem;
  color: var(--purple);
}

.menu-btn {
  font-size: 1.6rem;
  background: none;
  border: none;
  cursor: pointer;
}

.menu {
  position: fixed;
  top: 70px;
  right: 20px;
  background: white;
  border-radius: 14px;
  box-shadow: 0 20px 40px rgba(0,0,0,.15);
  min-width: 200px;
  display: flex;
  flex-direction: column;
  z-index: 9999;
}

.menu.hidden {
  display: none;
}

.menu a {
  padding: 1rem;
  font-weight: 600;
  color: var(--purple);
}

.menu a:hover {
  background: #eef2ff;
}

.hidden {
  display: none;
}

.topbar {
  padding: 1rem;
  background: linear-gradient(135deg, var(--purple), var(--azure));
}

.back {
  color: white;
  text-decoration: none;
  font-weight: bold;
}

.board {
  display: grid;
  grid-template-columns: repeat(3, 100px);
  gap: 12px;
  justify-content: center;
  margin: 10rem auto;
  
}

.cell {
  width: 100px;
  height: 100px;
  font-size: 2.5rem;
  font-weight: bold;
  border-radius: 12px;
  border: none;
  cursor: pointer;
  background: var(--card);
  color: var(--text);
}

.cell:focus {
  outline: 3px solid var(--azure);
}

.btn {
  padding: 0.6rem 1.4rem;
  border-radius: 999px;
  border: none;
  cursor: pointer;
  font-weight: bold;
  background: linear-gradient(135deg, var(--purple), var(--azure));
  color: white;

}