body {
  margin: 0;
  padding: 0;
  font-family: sans-serif;
  background-size: cover;
  background-repeat: no-repeat;
  background-position: center;
}

.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px;
  background: rgba(255, 255, 255, 0.8);
}

.logo {
  height: 50px;
}

.auth a {
  font-size: 16px;
  color: #333;
  text-decoration: none;
  padding: 8px 12px;
  border: 1px solid #666;
  border-radius: 6px;
  background: #eee;
}

.icon-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  padding: 20px;
  justify-items: center;
}

.icon-box {
  position: relative;
  cursor: pointer;
  transition: transform 0.2s ease;
}

.icon-box:hover {
  transform: scale(1.2);
}

.icon {
  width: 80px;
  height: 80px;
}

.label {
  display: none;
  position: absolute;
  top: 90px;
  background: rgba(0, 0, 0, 0.7);
  color: #fff;
  padding: 4px 8px;
  border-radius: 4px;
  white-space: nowrap;
  font-size: 14px;
}

.nav-bar {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  display: flex;
  justify-content: space-around;
  background: rgba(255, 255, 255, 0.95);
  padding: 10px 0;
  border-top: 1px solid #ccc;
}

.nav-bar a {
  text-decoration: none;
  color: #000;
  font-size: 16px;
}

/* RWD 修正：手機上 logo 與登入排版 */
@media (max-width: 768px) {
  .header {
    flex-direction: column;
    align-items: flex-start;
  }

  .auth {
    align-self: flex-end;
    margin-top: 8px;
  }

  .auth a {
    font-size: 14px;
    padding: 4px 8px;
    word-break: keep-all;
  }

  .logo {
    height: 40px;
  }
}