body {
  font-family: Georgia, serif;
  background-color: #fff;       /* white background */
  color: #222;                  /* dark text */
  margin: 0;
  padding: 1em;
}

/* HEADER */
header {
  text-align: center;
  margin-bottom: 1em;
  padding-bottom: 0.5em;
  background-color: #fff;
  /* no border bottom */
}

h1 {
  font-family: monospace;
  font-size: 2em;
  margin: 0;
  color: #0b2e66;               /* dark blue */
  letter-spacing: 0.1em;
  display: inline-block;
  /* Removed border-bottom */
  padding-bottom: 0;
}

/* NAVIGATION */
.nav-buttons {
  display: flex;
  justify-content: center;
  gap: 1em;
  background-color: #f7f8fa;    /* light grey */
  padding: 1em 0;
  border-top: 1px solid #ccc;
  border-bottom: 1px solid #ccc;
  box-shadow: inset 0 1px 2px rgba(255, 255, 255, 0.6);
}

.nav-button {
  font-family: monospace;
  font-size: 1em;
  padding: 0.6em 1.2em;
  color: #0b2e66;              /* dark blue text */
  text-decoration: none;
  background: linear-gradient(to bottom, #e8ebf1, #cfd6e6);  /* light grey/blue gradient */
  border: 1px solid #8b9acb;   /* muted blue-grey border */
  border-radius: 6px;
  box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.1);
  transition: all 0.2s ease;
}

.nav-button:hover {
  background: linear-gradient(to bottom, #c7cee1, #a0accf);
  box-shadow: 2px 2px 4px rgba(0, 0, 0, 0.15);
  color: #fff;                 /* text changes to white on hover */
  border-color: #4b5d9f;       /* darker blue border on hover */
}

.nav-button.active {
  background: #4b5d9f;         /* dark blue */
  font-weight: bold;
  cursor: default;
  border-color: #354a7b;
  color: #fff;                 /* white text for active */
}

/* MAIN CONTENT */
main {
  max-width: 700px;
  margin: 0 auto;
}